[PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Petr Machata]

Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. In practice
that means that MC routing configuration needs to be kept in sync with the
VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC
routing code instead.

To that end, this patchset adds support to route locally generated
multicast packets.

However, an installation that uses a VXLAN underlay netdevice for which it
also has matching MC routes, would get a different routing with this patch.
Previously, the MC packets would be delivered directly to the underlay
port, whereas now they would be MC-routed. In order to avoid this change in
behavior, introduce an IPCB/IP6CB flag. Unless the flag is set, the new
MC-routing code is skipped.

All this is keyed to a new VXLAN attribute, IFLA_VXLAN_MC_ROUTE. Only when
it is set does any of the above engage.

In addition to that, and as is the case today with MC forwarding,
IPV4_DEVCONF_MC_FORWARDING must be enabled for the netdevice that acts as a
source of MC traffic (i.e. the VXLAN PHYS_DEV), so an MC daemon must be
attached to the netdevice.

When a VXLAN netdevice with a MC remote is brought up, the physical
netdevice joins the indicated MC group. This is important for local
delivery of MC packets, so it is still necessary to configure a physical
netdevice -- the parameter cannot go away. The netdevice would however
typically not be a front panel port, but a dummy. An MC daemon would then
sit on top of that netdevice as well as any front panel ports that it needs
to service, and have routes set up between the two.

A way to configure the VXLAN netdevice to take advantage of the new MC
routing would be:

 # ip link add name d up type dummy
 # ip link add name vx10 up type vxlan id 1000 dstport 4789 \
	local 192.0.2.1 group 225.0.0.1 ttl 16 dev d mrcoute
 # ip link set dev vx10 master br # plus vlans etc.

With the following MC routes:

 (192.0.2.1, 225.0.0.1) iif=d oil=swp1,swp2 # TX route
 (*, 225.0.0.1) iif=swp1 oil=d,swp2         # RX route
 (*, 225.0.0.1) iif=swp2 oil=d,swp1         # RX route

The RX path has not changed, with the exception of an extra MC hop. Packets
are delivered to the front panel port and MC-forwarded to the VXLAN
physical port, here "d". Since the port has joined the multicast group, the
packets are locally delivered, and end up being processed by the VXLAN
netdevice.

This patchset is based on earlier patches from Nikolay Aleksandrov and
Roopa Prabhu, though it underwent significant changes. Roopa broadly
presented the topic on LPC 2019 [0].

Patchset progression:

- Patches #1 to #4 add ip_mr_output()
- Patches #5 to #9 add ip6_mr_output()
- Patch #10 adds the VXLAN bits to enable MR engagement
- Patches #11 to #13 prepare selftest libraries
- Patch #14 includes a new test suite

[0] https://www.youtube.com/watch?v=xlReECfi-uo

Petr Machata (14):
  net: ipv4: Add a flags argument to iptunnel_xmit(),
    udp_tunnel_xmit_skb()
  net: ipv4: ipmr: ipmr_queue_xmit(): Drop local variable `dev'
  net: ipv4: ipmr: Split ipmr_queue_xmit() in two
  net: ipv4: Add ip_mr_output()
  net: ipv6: Make udp_tunnel6_xmit_skb() void
  net: ipv6: Add a flags argument to ip6tunnel_xmit(),
    udp_tunnel6_xmit_skb()
  net: ipv6: ip6mr: Fix in/out netdev to pass to the FORWARD chain
  net: ipv6: ip6mr: Extract a helper out of ip6mr_forward2()
  net: ipv6: Add ip6_mr_output()
  vxlan: Support MC routing in the underlay
  selftests: forwarding: lib: Move smcrouted helpers here
  selftests: net: lib: Add ip_link_has_flag()
  selftests: forwarding: adf_mcd_start(): Allow configuring custom
    interfaces
  selftests: forwarding: Add a test for verifying VXLAN MC underlay

 drivers/net/amt.c                             |   9 +-
 drivers/net/bareudp.c                         |   7 +-
 drivers/net/geneve.c                          |   7 +-
 drivers/net/gtp.c                             |  12 +-
 drivers/net/ovpn/udp.c                        |   4 +-
 drivers/net/vxlan/vxlan_core.c                |  23 +-
 drivers/net/wireguard/socket.c                |   4 +-
 include/linux/ipv6.h                          |   1 +
 include/linux/mroute6.h                       |   7 +
 include/net/ip.h                              |   2 +
 include/net/ip6_tunnel.h                      |   3 +-
 include/net/ip_tunnels.h                      |   2 +-
 include/net/udp_tunnel.h                      |  17 +-
 include/net/vxlan.h                           |   5 +-
 include/uapi/linux/if_link.h                  |   1 +
 net/ipv4/ip_tunnel.c                          |   4 +-
 net/ipv4/ip_tunnel_core.c                     |   4 +-
 net/ipv4/ipmr.c                               | 169 +++-
 net/ipv4/route.c                              |   2 +-
 net/ipv4/udp_tunnel_core.c                    |   5 +-
 net/ipv6/ip6_tunnel.c                         |   2 +-
 net/ipv6/ip6_udp_tunnel.c                     |  18 +-
 net/ipv6/ip6mr.c                              | 137 +++-
 net/ipv6/route.c                              |   1 +
 net/ipv6/sit.c                                |   2 +-
 net/sctp/ipv6.c                               |   7 +-
 net/sctp/protocol.c                           |   3 +-
 net/tipc/udp_media.c                          |  12 +-
 .../testing/selftests/net/forwarding/Makefile |   1 +
 tools/testing/selftests/net/forwarding/lib.sh |  43 +
 .../net/forwarding/router_multicast.sh        |  31 +-
 .../net/forwarding/vxlan_bridge_1q_mc_ul.sh   | 757 ++++++++++++++++++
 tools/testing/selftests/net/lib.sh            |  12 +-
 33 files changed, 1199 insertions(+), 115 deletions(-)
 create mode 100755 tools/testing/selftests/net/forwarding/vxlan_bridge_1q_mc_ul.sh

-- 
2.49.0

[PATCH net-next 01/14] net: ipv4: Add a flags argument to iptunnel_xmit(), udp_tunnel_xmit_skb()

[Petr Machata]

iptunnel_xmit() erases the contents of the SKB control block. In order to
be able to set particular IPCB flags on the SKB, add a corresponding
parameter, and propagate it to udp_tunnel_xmit_skb() as well.

In one of the following patches, VXLAN driver will use this facility to
mark packets as subject to IP multicast routing.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---

Notes:
CC: Pablo Neira Ayuso <pablo@netfilter.org>
CC: osmocom-net-gprs@lists.osmocom.org
CC: Andrew Lunn <andrew+netdev@lunn.ch>
CC: Taehee Yoo <ap420073@gmail.com>
CC: Antonio Quartulli <antonio@openvpn.net>
CC: "Jason A. Donenfeld" <Jason@zx2c4.com>
CC: wireguard@lists.zx2c4.com
CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
CC: linux-sctp@vger.kernel.org
CC: Jon Maloy <jmaloy@redhat.com>
CC: tipc-discussion@lists.sourceforge.net

 drivers/net/amt.c              |  9 ++++++---
 drivers/net/bareudp.c          |  4 ++--
 drivers/net/geneve.c           |  4 ++--
 drivers/net/gtp.c              | 10 ++++++----
 drivers/net/ovpn/udp.c         |  2 +-
 drivers/net/vxlan/vxlan_core.c |  2 +-
 drivers/net/wireguard/socket.c |  2 +-
 include/net/ip_tunnels.h       |  2 +-
 include/net/udp_tunnel.h       |  2 +-
 net/ipv4/ip_tunnel.c           |  4 ++--
 net/ipv4/ip_tunnel_core.c      |  4 +++-
 net/ipv4/udp_tunnel_core.c     |  5 +++--
 net/ipv6/sit.c                 |  2 +-
 net/sctp/protocol.c            |  3 ++-
 net/tipc/udp_media.c           |  2 +-
 15 files changed, 33 insertions(+), 24 deletions(-)

diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index 734a0b3242a9..d0f719531499 100644
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c
@@ -1046,7 +1046,8 @@ static bool amt_send_membership_update(struct amt_dev *amt,
 			    amt->gw_port,
 			    amt->relay_port,
 			    false,
-			    false);
+			    false,
+			    0);
 	amt_update_gw_status(amt, AMT_STATUS_SENT_UPDATE, true);
 	return false;
 }
@@ -1103,7 +1104,8 @@ static void amt_send_multicast_data(struct amt_dev *amt,
 			    amt->relay_port,
 			    tunnel->source_port,
 			    false,
-			    false);
+			    false,
+			    0);
 }
 
 static bool amt_send_membership_query(struct amt_dev *amt,
@@ -1161,7 +1163,8 @@ static bool amt_send_membership_query(struct amt_dev *amt,
 			    amt->relay_port,
 			    tunnel->source_port,
 			    false,
-			    false);
+			    false,
+			    0);
 	amt_update_relay_status(tunnel, AMT_STATUS_SENT_QUERY, true);
 	return false;
 }
diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index a9dffdcac805..5e613080d3f8 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -362,8 +362,8 @@ static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	udp_tunnel_xmit_skb(rt, sock->sk, skb, saddr, info->key.u.ipv4.dst,
 			    tos, ttl, df, sport, bareudp->port,
 			    !net_eq(bareudp->net, dev_net(bareudp->dev)),
-			    !test_bit(IP_TUNNEL_CSUM_BIT,
-				      info->key.tun_flags));
+			    !test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags),
+			    0);
 	return 0;
 
 free_dst:
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index ffc15a432689..c668e8b00ed2 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -921,8 +921,8 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	udp_tunnel_xmit_skb(rt, gs4->sock->sk, skb, saddr, info->key.u.ipv4.dst,
 			    tos, ttl, df, sport, geneve->cfg.info.key.tp_dst,
 			    !net_eq(geneve->net, dev_net(geneve->dev)),
-			    !test_bit(IP_TUNNEL_CSUM_BIT,
-				      info->key.tun_flags));
+			    !test_bit(IP_TUNNEL_CSUM_BIT, info->key.tun_flags),
+			    0);
 	return 0;
 }
 
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index d4dec741c7f4..14584793fe4e 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -446,7 +446,8 @@ static int gtp0_send_echo_resp_ip(struct gtp_dev *gtp, struct sk_buff *skb)
 			    htons(GTP0_PORT), htons(GTP0_PORT),
 			    !net_eq(sock_net(gtp->sk1u),
 				    dev_net(gtp->dev)),
-			    false);
+			    false,
+			    0);
 
 	return 0;
 }
@@ -704,7 +705,8 @@ static int gtp1u_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
 			    htons(GTP1U_PORT), htons(GTP1U_PORT),
 			    !net_eq(sock_net(gtp->sk1u),
 				    dev_net(gtp->dev)),
-			    false);
+			    false,
+			    0);
 	return 0;
 }
 
@@ -1304,7 +1306,7 @@ static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 				    pktinfo.gtph_port, pktinfo.gtph_port,
 				    !net_eq(sock_net(pktinfo.pctx->sk),
 					    dev_net(dev)),
-				    false);
+				    false, 0);
 		break;
 	case AF_INET6:
 #if IS_ENABLED(CONFIG_IPV6)
@@ -2405,7 +2407,7 @@ static int gtp_genl_send_echo_req(struct sk_buff *skb, struct genl_info *info)
 			    port, port,
 			    !net_eq(sock_net(sk),
 				    dev_net(gtp->dev)),
-			    false);
+			    false, 0);
 	return 0;
 }
 
diff --git a/drivers/net/ovpn/udp.c b/drivers/net/ovpn/udp.c
index bff00946eae2..d866e6bfda70 100644
--- a/drivers/net/ovpn/udp.c
+++ b/drivers/net/ovpn/udp.c
@@ -199,7 +199,7 @@ static int ovpn_udp4_output(struct ovpn_peer *peer, struct ovpn_bind *bind,
 transmit:
 	udp_tunnel_xmit_skb(rt, sk, skb, fl.saddr, fl.daddr, 0,
 			    ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport,
-			    fl.fl4_dport, false, sk->sk_no_check_tx);
+			    fl.fl4_dport, false, sk->sk_no_check_tx, 0);
 	ret = 0;
 err:
 	local_bh_enable();
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index a56d7239b127..d7a5d8873a1b 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2522,7 +2522,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
 		udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, saddr,
 				    pkey->u.ipv4.dst, tos, ttl, df,
-				    src_port, dst_port, xnet, !udp_sum);
+				    src_port, dst_port, xnet, !udp_sum, 0);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index 0414d7a6ce74..88e685667bc0 100644
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c
@@ -84,7 +84,7 @@ static int send4(struct wg_device *wg, struct sk_buff *skb,
 	skb->ignore_df = 1;
 	udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds,
 			    ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport,
-			    fl.fl4_dport, false, false);
+			    fl.fl4_dport, false, false, 0);
 	goto out;
 
 err:
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 0c3d571a04a1..8cf1380f3656 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -603,7 +603,7 @@ static inline int iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 
 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 		   __be32 src, __be32 dst, u8 proto,
-		   u8 tos, u8 ttl, __be16 df, bool xnet);
+		   u8 tos, u8 ttl, __be16 df, bool xnet, u16 ipcb_flags);
 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 					     gfp_t flags);
 int skb_tunnel_check_pmtu(struct sk_buff *skb, struct dst_entry *encap_dst,
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 2df3b8344eb5..28102c8fd8a8 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -150,7 +150,7 @@ static inline void udp_tunnel_drop_rx_info(struct net_device *dev)
 void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
 			 __be16 df, __be16 src_port, __be16 dst_port,
-			 bool xnet, bool nocheck);
+			 bool xnet, bool nocheck, u16 ipcb_flags);
 
 int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 			 struct sk_buff *skb,
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 678b8f96e3e9..aaeb5d16f0c9 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -668,7 +668,7 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 	ip_tunnel_adj_headroom(dev, headroom);
 
 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, proto, tos, ttl,
-		      df, !net_eq(tunnel->net, dev_net(dev)));
+		      df, !net_eq(tunnel->net, dev_net(dev)), 0);
 	return;
 tx_error:
 	DEV_STATS_INC(dev, tx_errors);
@@ -857,7 +857,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 	ip_tunnel_adj_headroom(dev, max_headroom);
 
 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
-		      df, !net_eq(tunnel->net, dev_net(dev)));
+		      df, !net_eq(tunnel->net, dev_net(dev)), 0);
 	return;
 
 #if IS_ENABLED(CONFIG_IPV6)
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index f65d2f727381..cc9915543637 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -49,7 +49,8 @@ EXPORT_SYMBOL(ip6tun_encaps);
 
 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 		   __be32 src, __be32 dst, __u8 proto,
-		   __u8 tos, __u8 ttl, __be16 df, bool xnet)
+		   __u8 tos, __u8 ttl, __be16 df, bool xnet,
+		   u16 ipcb_flags)
 {
 	int pkt_len = skb->len - skb_inner_network_offset(skb);
 	struct net *net = dev_net(rt->dst.dev);
@@ -62,6 +63,7 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 	skb_clear_hash_if_not_l4(skb);
 	skb_dst_set(skb, &rt->dst);
 	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+	IPCB(skb)->flags = ipcb_flags;
 
 	/* Push down and install the IP header. */
 	skb_push(skb, sizeof(struct iphdr));
diff --git a/net/ipv4/udp_tunnel_core.c b/net/ipv4/udp_tunnel_core.c
index 2326548997d3..9efd62505916 100644
--- a/net/ipv4/udp_tunnel_core.c
+++ b/net/ipv4/udp_tunnel_core.c
@@ -169,7 +169,7 @@ EXPORT_SYMBOL_GPL(udp_tunnel_notify_del_rx_port);
 void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
 			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
 			 __be16 df, __be16 src_port, __be16 dst_port,
-			 bool xnet, bool nocheck)
+			 bool xnet, bool nocheck, u16 ipcb_flags)
 {
 	struct udphdr *uh;
 
@@ -185,7 +185,8 @@ void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb
 
 	udp_set_csum(nocheck, skb, src, dst, skb->len);
 
-	iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet);
+	iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet,
+		      ipcb_flags);
 }
 EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
 
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index a72dbca9e8fc..12496ba1b7d4 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1035,7 +1035,7 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 	skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 
 	iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
-		      df, !net_eq(tunnel->net, dev_net(dev)));
+		      df, !net_eq(tunnel->net, dev_net(dev)), 0);
 	return NETDEV_TX_OK;
 
 tx_error_icmp:
diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 8c3b80c4d40b..bfbb73e359f5 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1103,7 +1103,8 @@ static inline int sctp_v4_xmit(struct sk_buff *skb, struct sctp_transport *t)
 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
 	udp_tunnel_xmit_skb(dst_rtable(dst), sk, skb, fl4->saddr,
 			    fl4->daddr, dscp, ip4_dst_hoplimit(dst), df,
-			    sctp_sk(sk)->udp_port, t->encap_port, false, false);
+			    sctp_sk(sk)->udp_port, t->encap_port, false, false,
+			    0);
 	return 0;
 }
 
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 108a4cc2e001..87e8c1e6d550 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -197,7 +197,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 		ttl = ip4_dst_hoplimit(&rt->dst);
 		udp_tunnel_xmit_skb(rt, ub->ubsock->sk, skb, src->ipv4.s_addr,
 				    dst->ipv4.s_addr, 0, ttl, 0, src->port,
-				    dst->port, false, true);
+				    dst->port, false, true, 0);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		if (!ndst) {
-- 
2.49.0

Re: [PATCH net-next 01/14] net: ipv4: Add a flags argument to iptunnel_xmit(), udp_tunnel_xmit_skb()

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> iptunnel_xmit() erases the contents of the SKB control block. In order to
> be able to set particular IPCB flags on the SKB, add a corresponding
> parameter, and propagate it to udp_tunnel_xmit_skb() as well.
> 
> In one of the following patches, VXLAN driver will use this facility to
> mark packets as subject to IP multicast routing.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
> CC: Pablo Neira Ayuso <pablo@netfilter.org>
> CC: osmocom-net-gprs@lists.osmocom.org
> CC: Andrew Lunn <andrew+netdev@lunn.ch>
> CC: Taehee Yoo <ap420073@gmail.com>
> CC: Antonio Quartulli <antonio@openvpn.net>
> CC: "Jason A. Donenfeld" <Jason@zx2c4.com>
> CC: wireguard@lists.zx2c4.com
> CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> CC: linux-sctp@vger.kernel.org
> CC: Jon Maloy <jmaloy@redhat.com>
> CC: tipc-discussion@lists.sourceforge.net
> 
>   drivers/net/amt.c              |  9 ++++++---
>   drivers/net/bareudp.c          |  4 ++--
>   drivers/net/geneve.c           |  4 ++--
>   drivers/net/gtp.c              | 10 ++++++----
>   drivers/net/ovpn/udp.c         |  2 +-
>   drivers/net/vxlan/vxlan_core.c |  2 +-
>   drivers/net/wireguard/socket.c |  2 +-
>   include/net/ip_tunnels.h       |  2 +-
>   include/net/udp_tunnel.h       |  2 +-
>   net/ipv4/ip_tunnel.c           |  4 ++--
>   net/ipv4/ip_tunnel_core.c      |  4 +++-
>   net/ipv4/udp_tunnel_core.c     |  5 +++--
>   net/ipv6/sit.c                 |  2 +-
>   net/sctp/protocol.c            |  3 ++-
>   net/tipc/udp_media.c           |  2 +-
>   15 files changed, 33 insertions(+), 24 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

Re: [PATCH net-next 01/14] net: ipv4: Add a flags argument to iptunnel_xmit(), udp_tunnel_xmit_skb()

[Antonio Quartulli]

On 09/06/2025 22:50, Petr Machata wrote:
> iptunnel_xmit() erases the contents of the SKB control block. In order to
> be able to set particular IPCB flags on the SKB, add a corresponding
> parameter, and propagate it to udp_tunnel_xmit_skb() as well.
> 
> In one of the following patches, VXLAN driver will use this facility to
> mark packets as subject to IP multicast routing.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
> CC: Pablo Neira Ayuso <pablo@netfilter.org>
> CC: osmocom-net-gprs@lists.osmocom.org
> CC: Andrew Lunn <andrew+netdev@lunn.ch>
> CC: Taehee Yoo <ap420073@gmail.com>
> CC: Antonio Quartulli <antonio@openvpn.net>
> CC: "Jason A. Donenfeld" <Jason@zx2c4.com>
> CC: wireguard@lists.zx2c4.com
> CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> CC: linux-sctp@vger.kernel.org
> CC: Jon Maloy <jmaloy@redhat.com>
> CC: tipc-discussion@lists.sourceforge.net

Acked-by: Antonio Quartulli <antonio@openvpn.net>


-- 
Antonio Quartulli
OpenVPN Inc.

[PATCH net-next 02/14] net: ipv4: ipmr: ipmr_queue_xmit(): Drop local variable `dev'

[Petr Machata]

The variable is used for caching of rt->dst.dev. The netdevice referenced
therein does not change during the scope of validity of that local. At the
same time, the local is only used twice, and each of these uses will end up
in a different function in the following patches, further eliminating any
use the local could have had.

Drop the local altogether and inline the uses.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/ipmr.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 2ff2f79c7351..1c5e6167cd76 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1859,7 +1859,6 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 	const struct iphdr *iph = ip_hdr(skb);
 	struct vif_device *vif = &mrt->vif_table[vifi];
 	struct net_device *vif_dev;
-	struct net_device *dev;
 	struct rtable *rt;
 	struct flowi4 fl4;
 	int    encap = 0;
@@ -1898,8 +1897,6 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 			goto out_free;
 	}
 
-	dev = rt->dst.dev;
-
 	if (skb->len+encap > dst_mtu(&rt->dst) && (ntohs(iph->frag_off) & IP_DF)) {
 		/* Do not fragment multicasts. Alas, IPv4 does not
 		 * allow to send ICMP, so that packets will disappear
@@ -1910,7 +1907,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		goto out_free;
 	}
 
-	encap += LL_RESERVED_SPACE(dev) + rt->dst.header_len;
+	encap += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
 
 	if (skb_cow(skb, encap)) {
 		ip_rt_put(rt);
@@ -1947,7 +1944,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 	 * result in receiving multiple packets.
 	 */
 	NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD,
-		net, NULL, skb, skb->dev, dev,
+		net, NULL, skb, skb->dev, rt->dst.dev,
 		ipmr_forward_finish);
 	return;
 
-- 
2.49.0

Re: [PATCH net-next 02/14] net: ipv4: ipmr: ipmr_queue_xmit(): Drop local variable `dev'

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> The variable is used for caching of rt->dst.dev. The netdevice referenced
> therein does not change during the scope of validity of that local. At the
> same time, the local is only used twice, and each of these uses will end up
> in a different function in the following patches, further eliminating any
> use the local could have had.
> 
> Drop the local altogether and inline the uses.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
>   net/ipv4/ipmr.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 03/14] net: ipv4: ipmr: Split ipmr_queue_xmit() in two

[Petr Machata]

Some of the work of ipmr_queue_xmit() is specific to IPMR forwarding, and
should not take place on the output path. In order to allow reuse of the
common parts, split the function into two: the ipmr_prepare_xmit() helper
that takes care of the common bits, and the ipmr_queue_fwd_xmit(), which
invokes the former and encapsulates the whole forwarding algorithm.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/ipmr.c | 45 +++++++++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 16 deletions(-)

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 1c5e6167cd76..7c1045d67ea8 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1853,8 +1853,8 @@ static bool ipmr_forward_offloaded(struct sk_buff *skb, struct mr_table *mrt,
 
 /* Processing handlers for ipmr_forward, under rcu_read_lock() */
 
-static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
-			    int in_vifi, struct sk_buff *skb, int vifi)
+static int ipmr_prepare_xmit(struct net *net, struct mr_table *mrt,
+			     struct sk_buff *skb, int vifi)
 {
 	const struct iphdr *iph = ip_hdr(skb);
 	struct vif_device *vif = &mrt->vif_table[vifi];
@@ -1865,7 +1865,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 
 	vif_dev = vif_dev_read(vif);
 	if (!vif_dev)
-		goto out_free;
+		return -1;
 
 	if (vif->flags & VIFF_REGISTER) {
 		WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
@@ -1873,12 +1873,9 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		DEV_STATS_ADD(vif_dev, tx_bytes, skb->len);
 		DEV_STATS_INC(vif_dev, tx_packets);
 		ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);
-		goto out_free;
+		return -1;
 	}
 
-	if (ipmr_forward_offloaded(skb, mrt, in_vifi, vifi))
-		goto out_free;
-
 	if (vif->flags & VIFF_TUNNEL) {
 		rt = ip_route_output_ports(net, &fl4, NULL,
 					   vif->remote, vif->local,
@@ -1886,7 +1883,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 					   IPPROTO_IPIP,
 					   iph->tos & INET_DSCP_MASK, vif->link);
 		if (IS_ERR(rt))
-			goto out_free;
+			return -1;
 		encap = sizeof(struct iphdr);
 	} else {
 		rt = ip_route_output_ports(net, &fl4, NULL, iph->daddr, 0,
@@ -1894,7 +1891,7 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 					   IPPROTO_IPIP,
 					   iph->tos & INET_DSCP_MASK, vif->link);
 		if (IS_ERR(rt))
-			goto out_free;
+			return -1;
 	}
 
 	if (skb->len+encap > dst_mtu(&rt->dst) && (ntohs(iph->frag_off) & IP_DF)) {
@@ -1904,14 +1901,14 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		 */
 		IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
 		ip_rt_put(rt);
-		goto out_free;
+		return -1;
 	}
 
 	encap += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
 
 	if (skb_cow(skb, encap)) {
 		ip_rt_put(rt);
-		goto out_free;
+		return -1;
 	}
 
 	WRITE_ONCE(vif->pkt_out, vif->pkt_out + 1);
@@ -1931,6 +1928,22 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt,
 		DEV_STATS_ADD(vif_dev, tx_bytes, skb->len);
 	}
 
+	return 0;
+}
+
+static void ipmr_queue_fwd_xmit(struct net *net, struct mr_table *mrt,
+				int in_vifi, struct sk_buff *skb, int vifi)
+{
+	struct rtable *rt;
+
+	if (ipmr_forward_offloaded(skb, mrt, in_vifi, vifi))
+		goto out_free;
+
+	if (ipmr_prepare_xmit(net, mrt, skb, vifi))
+		goto out_free;
+
+	rt = skb_rtable(skb);
+
 	IPCB(skb)->flags |= IPSKB_FORWARDED;
 
 	/* RFC1584 teaches, that DVMRP/PIM router must deliver packets locally
@@ -2062,8 +2075,8 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
 				if (skb2)
-					ipmr_queue_xmit(net, mrt, true_vifi,
-							skb2, psend);
+					ipmr_queue_fwd_xmit(net, mrt, true_vifi,
+							    skb2, psend);
 			}
 			psend = ct;
 		}
@@ -2074,10 +2087,10 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt,
 			struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
 			if (skb2)
-				ipmr_queue_xmit(net, mrt, true_vifi, skb2,
-						psend);
+				ipmr_queue_fwd_xmit(net, mrt, true_vifi, skb2,
+						    psend);
 		} else {
-			ipmr_queue_xmit(net, mrt, true_vifi, skb, psend);
+			ipmr_queue_fwd_xmit(net, mrt, true_vifi, skb, psend);
 			return;
 		}
 	}
-- 
2.49.0

Re: [PATCH net-next 03/14] net: ipv4: ipmr: Split ipmr_queue_xmit() in two

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Some of the work of ipmr_queue_xmit() is specific to IPMR forwarding, and
> should not take place on the output path. In order to allow reuse of the
> common parts, split the function into two: the ipmr_prepare_xmit() helper
> that takes care of the common bits, and the ipmr_queue_fwd_xmit(), which
> invokes the former and encapsulates the whole forwarding algorithm.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
>   net/ipv4/ipmr.c | 45 +++++++++++++++++++++++++++++----------------
>   1 file changed, 29 insertions(+), 16 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 04/14] net: ipv4: Add ip_mr_output()

[Petr Machata]

Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code today. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. Thus MC
routing configuration needs to be kept in sync with the VXLAN FDB and MDB.
Ideally, the VXLAN packets would be routed by the MC routing code instead.

To that end, this patch adds support to route locally generated multicast
packets. The newly-added routines do largely what ip_mr_input() and
ip_mr_forward() do: make an MR cache lookup to find where to send the
packets, and use ip_mc_output() to send each of them. When no cache entry
is found, the packet is punted to the daemon for resolution.

However, an installation that uses a VXLAN underlay netdevice for which it
also has matching MC routes, would get a different routing with this patch.
Previously, the MC packets would be delivered directly to the underlay
port, whereas now they would be MC-routed. In order to avoid this change in
behavior, introduce an IPCB flag. Only if the flag is set will
ip_mr_output() actually engage, otherwise it reverts to ip_mc_output().

This code is based on work by Roopa Prabhu and Nikolay Aleksandrov.

Signed-off-by: Roopa Prabhu <roopa@nvidia.com>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Benjamin Poirier <bpoirier@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 include/net/ip.h |   2 +
 net/ipv4/ipmr.c  | 117 +++++++++++++++++++++++++++++++++++++++++++++++
 net/ipv4/route.c |   2 +-
 3 files changed, 120 insertions(+), 1 deletion(-)

diff --git a/include/net/ip.h b/include/net/ip.h
index 47ed6d23853d..375304bb99f6 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -59,6 +59,7 @@ struct inet_skb_parm {
 #define IPSKB_L3SLAVE		BIT(7)
 #define IPSKB_NOPOLICY		BIT(8)
 #define IPSKB_MULTIPATH		BIT(9)
+#define IPSKB_MCROUTE		BIT(10)
 
 	u16			frag_max_size;
 };
@@ -167,6 +168,7 @@ void ip_list_rcv(struct list_head *head, struct packet_type *pt,
 int ip_local_deliver(struct sk_buff *skb);
 void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
 int ip_mr_input(struct sk_buff *skb);
+int ip_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 7c1045d67ea8..f5268a9211e1 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1965,6 +1965,19 @@ static void ipmr_queue_fwd_xmit(struct net *net, struct mr_table *mrt,
 	kfree_skb(skb);
 }
 
+static void ipmr_queue_output_xmit(struct net *net, struct mr_table *mrt,
+				   struct sk_buff *skb, int vifi)
+{
+	if (ipmr_prepare_xmit(net, mrt, skb, vifi))
+		goto out_free;
+
+	ip_mc_output(net, NULL, skb);
+	return;
+
+out_free:
+	kfree_skb(skb);
+}
+
 /* Called with mrt_lock or rcu_read_lock() */
 static int ipmr_find_vif(const struct mr_table *mrt, struct net_device *dev)
 {
@@ -2224,6 +2237,110 @@ int ip_mr_input(struct sk_buff *skb)
 	return 0;
 }
 
+static void ip_mr_output_finish(struct net *net, struct mr_table *mrt,
+				struct net_device *dev, struct sk_buff *skb,
+				struct mfc_cache *c)
+{
+	int psend = -1;
+	int ct;
+
+	atomic_long_inc(&c->_c.mfc_un.res.pkt);
+	atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
+	WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);
+
+	/* Forward the frame */
+	if (c->mfc_origin == htonl(INADDR_ANY) &&
+	    c->mfc_mcastgrp == htonl(INADDR_ANY)) {
+		if (ip_hdr(skb)->ttl >
+				c->_c.mfc_un.res.ttls[c->_c.mfc_parent]) {
+			/* It's an (*,*) entry and the packet is not coming from
+			 * the upstream: forward the packet to the upstream
+			 * only.
+			 */
+			psend = c->_c.mfc_parent;
+			goto last_xmit;
+		}
+		goto dont_xmit;
+	}
+
+	for (ct = c->_c.mfc_un.res.maxvif - 1;
+	     ct >= c->_c.mfc_un.res.minvif; ct--) {
+		if (ip_hdr(skb)->ttl > c->_c.mfc_un.res.ttls[ct]) {
+			if (psend != -1) {
+				struct sk_buff *skb2 = skb_clone(skb,
+								 GFP_ATOMIC);
+
+				if (skb2)
+					ipmr_queue_output_xmit(net, mrt,
+							       skb2, psend);
+			}
+			psend = ct;
+		}
+	}
+
+last_xmit:
+	if (psend != -1) {
+		ipmr_queue_output_xmit(net, mrt, skb, psend);
+		return;
+	}
+
+dont_xmit:
+	kfree_skb(skb);
+}
+
+/* Multicast packets for forwarding arrive here
+ * Called with rcu_read_lock();
+ */
+int ip_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct rtable *rt = skb_rtable(skb);
+	struct mfc_cache *cache;
+	struct net_device *dev;
+	struct mr_table *mrt;
+	int vif;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+	dev = rt->dst.dev;
+
+	if (IPCB(skb)->flags & IPSKB_FORWARDED)
+		goto mc_output;
+	if (!(IPCB(skb)->flags & IPSKB_MCROUTE))
+		goto mc_output;
+
+	skb->dev = dev;
+
+	mrt = ipmr_rt_fib_lookup(net, skb);
+	if (IS_ERR(mrt))
+		goto mc_output;
+
+	/* already under rcu_read_lock() */
+	cache = ipmr_cache_find(mrt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
+	if (!cache) {
+		vif = ipmr_find_vif(mrt, dev);
+		if (vif >= 0)
+			cache = ipmr_cache_find_any(mrt, ip_hdr(skb)->daddr,
+						    vif);
+	}
+
+	/* No usable cache entry */
+	if (!cache) {
+		vif = ipmr_find_vif(mrt, dev);
+		if (vif >= 0)
+			return ipmr_cache_unresolved(mrt, vif, skb, dev);
+		goto mc_output;
+	}
+
+	vif = cache->_c.mfc_parent;
+	if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev)
+		goto mc_output;
+
+	ip_mr_output_finish(net, mrt, dev, skb, cache);
+	return 0;
+
+mc_output:
+	return ip_mc_output(net, sk, skb);
+}
+
 #ifdef CONFIG_IP_PIMSM_V1
 /* Handle IGMP messages of PIMv1 */
 int pim_rcv_v1(struct sk_buff *skb)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index fccb05fb3a79..3ddf6bf40357 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2660,7 +2660,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 			if (IN_DEV_MFORWARD(in_dev) &&
 			    !ipv4_is_local_multicast(fl4->daddr)) {
 				rth->dst.input = ip_mr_input;
-				rth->dst.output = ip_mc_output;
+				rth->dst.output = ip_mr_output;
 			}
 		}
 #endif
-- 
2.49.0

[PATCH net-next 05/14] net: ipv6: Make udp_tunnel6_xmit_skb() void

[Petr Machata]

The function always returns zero, thus the return value does not carry any
signal. Just make it void.

Most callers already ignore the return value. However:

- Refold arguments of the call from sctp_v6_xmit() so that they fit into
  the 80-column limit.

- tipc_udp_xmit() initializes err from the return value, but that should
  already be always zero at that point. So there's no practical change, but
  elision of the assignment prompts a couple more tweaks to clean up the
  function.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---

Notes:
CC:Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
CC:linux-sctp@vger.kernel.org
CC:Jon Maloy <jmaloy@redhat.com>
CC:tipc-discussion@lists.sourceforge.net

 include/net/udp_tunnel.h  | 14 +++++++-------
 net/ipv6/ip6_udp_tunnel.c | 15 +++++++--------
 net/sctp/ipv6.c           |  7 ++++---
 net/tipc/udp_media.c      | 10 +++++-----
 4 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 28102c8fd8a8..0b01f6ade20d 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -152,13 +152,13 @@ void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb
 			 __be16 df, __be16 src_port, __be16 dst_port,
 			 bool xnet, bool nocheck, u16 ipcb_flags);
 
-int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
-			 struct sk_buff *skb,
-			 struct net_device *dev,
-			 const struct in6_addr *saddr,
-			 const struct in6_addr *daddr,
-			 __u8 prio, __u8 ttl, __be32 label,
-			 __be16 src_port, __be16 dst_port, bool nocheck);
+void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			  struct sk_buff *skb,
+			  struct net_device *dev,
+			  const struct in6_addr *saddr,
+			  const struct in6_addr *daddr,
+			  __u8 prio, __u8 ttl, __be32 label,
+			  __be16 src_port, __be16 dst_port, bool nocheck);
 
 void udp_tunnel_sock_release(struct socket *sock);
 
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index c99053189ea8..21681718b7bb 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -74,13 +74,13 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 }
 EXPORT_SYMBOL_GPL(udp_sock_create6);
 
-int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
-			 struct sk_buff *skb,
-			 struct net_device *dev,
-			 const struct in6_addr *saddr,
-			 const struct in6_addr *daddr,
-			 __u8 prio, __u8 ttl, __be32 label,
-			 __be16 src_port, __be16 dst_port, bool nocheck)
+void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			  struct sk_buff *skb,
+			  struct net_device *dev,
+			  const struct in6_addr *saddr,
+			  const struct in6_addr *daddr,
+			  __u8 prio, __u8 ttl, __be32 label,
+			  __be16 src_port, __be16 dst_port, bool nocheck)
 {
 	struct udphdr *uh;
 	struct ipv6hdr *ip6h;
@@ -109,7 +109,6 @@ int udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 	ip6h->saddr	  = *saddr;
 
 	ip6tunnel_xmit(sk, skb, dev);
-	return 0;
 }
 EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);
 
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index a9ed2ccab1bd..d1ecf7454827 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -261,9 +261,10 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *t)
 	skb_set_inner_ipproto(skb, IPPROTO_SCTP);
 	label = ip6_make_flowlabel(sock_net(sk), skb, fl6->flowlabel, true, fl6);
 
-	return udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr,
-				    &fl6->daddr, tclass, ip6_dst_hoplimit(dst),
-				    label, sctp_sk(sk)->udp_port, t->encap_port, false);
+	udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr, &fl6->daddr,
+			     tclass, ip6_dst_hoplimit(dst), label,
+			     sctp_sk(sk)->udp_port, t->encap_port, false);
+	return 0;
 }
 
 /* Returns the dst cache entry for the given source and destination ip
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 87e8c1e6d550..414713fcd8c5 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -172,7 +172,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 			 struct udp_media_addr *dst, struct dst_cache *cache)
 {
 	struct dst_entry *ndst;
-	int ttl, err = 0;
+	int ttl, err;
 
 	local_bh_disable();
 	ndst = dst_cache_get(cache);
@@ -217,13 +217,13 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 			dst_cache_set_ip6(cache, ndst, &fl6.saddr);
 		}
 		ttl = ip6_dst_hoplimit(ndst);
-		err = udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
-					   &src->ipv6, &dst->ipv6, 0, ttl, 0,
-					   src->port, dst->port, false);
+		udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
+				     &src->ipv6, &dst->ipv6, 0, ttl, 0,
+				     src->port, dst->port, false);
 #endif
 	}
 	local_bh_enable();
-	return err;
+	return 0;
 
 tx_error:
 	local_bh_enable();
-- 
2.49.0

Re: [PATCH net-next 05/14] net: ipv6: Make udp_tunnel6_xmit_skb() void

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> The function always returns zero, thus the return value does not carry any
> signal. Just make it void.
> 
> Most callers already ignore the return value. However:
> 
> - Refold arguments of the call from sctp_v6_xmit() so that they fit into
>    the 80-column limit.
> 
> - tipc_udp_xmit() initializes err from the return value, but that should
>    already be always zero at that point. So there's no practical change, but
>    elision of the assignment prompts a couple more tweaks to clean up the
>    function.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
> CC:Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> CC:linux-sctp@vger.kernel.org
> CC:Jon Maloy <jmaloy@redhat.com>
> CC:tipc-discussion@lists.sourceforge.net
> 
>   include/net/udp_tunnel.h  | 14 +++++++-------
>   net/ipv6/ip6_udp_tunnel.c | 15 +++++++--------
>   net/sctp/ipv6.c           |  7 ++++---
>   net/tipc/udp_media.c      | 10 +++++-----
>   4 files changed, 23 insertions(+), 23 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 06/14] net: ipv6: Add a flags argument to ip6tunnel_xmit(), udp_tunnel6_xmit_skb()

[Petr Machata]

ip6tunnel_xmit() erases the contents of the SKB control block. In order to
be able to set particular IP6CB flags on the SKB, add a corresponding
parameter, and propagate it to udp_tunnel6_xmit_skb() as well.

In one of the following patches, VXLAN driver will use this facility to
mark packets as subject to IPv6 multicast routing.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---

Notes:
CC:Pablo Neira Ayuso <pablo@netfilter.org>
CC:osmocom-net-gprs@lists.osmocom.org
CC:Andrew Lunn <andrew+netdev@lunn.ch>
CC:Antonio Quartulli <antonio@openvpn.net>
CC:"Jason A. Donenfeld" <Jason@zx2c4.com>
CC:wireguard@lists.zx2c4.com
CC:Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
CC:linux-sctp@vger.kernel.org
CC:Jon Maloy <jmaloy@redhat.com>
CC:tipc-discussion@lists.sourceforge.net

 drivers/net/bareudp.c          | 3 ++-
 drivers/net/geneve.c           | 3 ++-
 drivers/net/gtp.c              | 2 +-
 drivers/net/ovpn/udp.c         | 2 +-
 drivers/net/vxlan/vxlan_core.c | 3 ++-
 drivers/net/wireguard/socket.c | 2 +-
 include/net/ip6_tunnel.h       | 3 ++-
 include/net/udp_tunnel.h       | 3 ++-
 net/ipv6/ip6_tunnel.c          | 2 +-
 net/ipv6/ip6_udp_tunnel.c      | 5 +++--
 net/sctp/ipv6.c                | 2 +-
 net/tipc/udp_media.c           | 2 +-
 12 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
index 5e613080d3f8..0df3208783ad 100644
--- a/drivers/net/bareudp.c
+++ b/drivers/net/bareudp.c
@@ -431,7 +431,8 @@ static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 			     &saddr, &daddr, prio, ttl,
 			     info->key.label, sport, bareudp->port,
 			     !test_bit(IP_TUNNEL_CSUM_BIT,
-				       info->key.tun_flags));
+				       info->key.tun_flags),
+			     0);
 	return 0;
 
 free_dst:
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index c668e8b00ed2..f6bd155aae7f 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1014,7 +1014,8 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 			     &saddr, &key->u.ipv6.dst, prio, ttl,
 			     info->key.label, sport, geneve->cfg.info.key.tp_dst,
 			     !test_bit(IP_TUNNEL_CSUM_BIT,
-				       info->key.tun_flags));
+				       info->key.tun_flags),
+			     0);
 	return 0;
 }
 #endif
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index 14584793fe4e..4b668ebaa0f7 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -1316,7 +1316,7 @@ static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 				     ip6_dst_hoplimit(&pktinfo.rt->dst),
 				     0,
 				     pktinfo.gtph_port, pktinfo.gtph_port,
-				     false);
+				     false, 0);
 #else
 		goto tx_err;
 #endif
diff --git a/drivers/net/ovpn/udp.c b/drivers/net/ovpn/udp.c
index d866e6bfda70..254cc94c4617 100644
--- a/drivers/net/ovpn/udp.c
+++ b/drivers/net/ovpn/udp.c
@@ -274,7 +274,7 @@ static int ovpn_udp6_output(struct ovpn_peer *peer, struct ovpn_bind *bind,
 	skb->ignore_df = 1;
 	udp_tunnel6_xmit_skb(dst, sk, skb, skb->dev, &fl.saddr, &fl.daddr, 0,
 			     ip6_dst_hoplimit(dst), 0, fl.fl6_sport,
-			     fl.fl6_dport, udp_get_no_check6_tx(sk));
+			     fl.fl6_dport, udp_get_no_check6_tx(sk), 0);
 	ret = 0;
 err:
 	local_bh_enable();
diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index d7a5d8873a1b..c4af6c652560 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2586,7 +2586,8 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
 		udp_tunnel6_xmit_skb(ndst, sock6->sock->sk, skb, dev,
 				     &saddr, &pkey->u.ipv6.dst, tos, ttl,
-				     pkey->label, src_port, dst_port, !udp_sum);
+				     pkey->label, src_port, dst_port, !udp_sum,
+				     0);
 #endif
 	}
 	vxlan_vnifilter_count(vxlan, vni, NULL, VXLAN_VNI_STATS_TX, pkt_len);
diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index 88e685667bc0..253488f8c00f 100644
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c
@@ -151,7 +151,7 @@ static int send6(struct wg_device *wg, struct sk_buff *skb,
 	skb->ignore_df = 1;
 	udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds,
 			     ip6_dst_hoplimit(dst), 0, fl.fl6_sport,
-			     fl.fl6_dport, false);
+			     fl.fl6_dport, false, 0);
 	goto out;
 
 err:
diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index 399592405c72..dd163495f353 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -152,11 +152,12 @@ int ip6_tnl_get_iflink(const struct net_device *dev);
 int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu);
 
 static inline void ip6tunnel_xmit(struct sock *sk, struct sk_buff *skb,
-				  struct net_device *dev)
+				  struct net_device *dev, u16 ip6cb_flags)
 {
 	int pkt_len, err;
 
 	memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
+	IP6CB(skb)->flags = ip6cb_flags;
 	pkt_len = skb->len - skb_inner_network_offset(skb);
 	err = ip6_local_out(dev_net(skb_dst(skb)->dev), sk, skb);
 
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 0b01f6ade20d..e3c70b579095 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -158,7 +158,8 @@ void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 			  const struct in6_addr *saddr,
 			  const struct in6_addr *daddr,
 			  __u8 prio, __u8 ttl, __be32 label,
-			  __be16 src_port, __be16 dst_port, bool nocheck);
+			  __be16 src_port, __be16 dst_port, bool nocheck,
+			  u16 ip6cb_flags);
 
 void udp_tunnel_sock_release(struct socket *sock);
 
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 894d3158a6f0..a885bb5c98ea 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1278,7 +1278,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
 	ipv6h->nexthdr = proto;
 	ipv6h->saddr = fl6->saddr;
 	ipv6h->daddr = fl6->daddr;
-	ip6tunnel_xmit(NULL, skb, dev);
+	ip6tunnel_xmit(NULL, skb, dev, 0);
 	return 0;
 tx_err_link_failure:
 	DEV_STATS_INC(dev, tx_carrier_errors);
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 21681718b7bb..8ebe17a6058a 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -80,7 +80,8 @@ void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 			  const struct in6_addr *saddr,
 			  const struct in6_addr *daddr,
 			  __u8 prio, __u8 ttl, __be32 label,
-			  __be16 src_port, __be16 dst_port, bool nocheck)
+			  __be16 src_port, __be16 dst_port, bool nocheck,
+			  u16 ip6cb_flags)
 {
 	struct udphdr *uh;
 	struct ipv6hdr *ip6h;
@@ -108,7 +109,7 @@ void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 	ip6h->daddr	  = *daddr;
 	ip6h->saddr	  = *saddr;
 
-	ip6tunnel_xmit(sk, skb, dev);
+	ip6tunnel_xmit(sk, skb, dev, ip6cb_flags);
 }
 EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);
 
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index d1ecf7454827..3336dcfb4515 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -263,7 +263,7 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *t)
 
 	udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr, &fl6->daddr,
 			     tclass, ip6_dst_hoplimit(dst), label,
-			     sctp_sk(sk)->udp_port, t->encap_port, false);
+			     sctp_sk(sk)->udp_port, t->encap_port, false, 0);
 	return 0;
 }
 
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 414713fcd8c5..a024fcc8c0cb 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -219,7 +219,7 @@ static int tipc_udp_xmit(struct net *net, struct sk_buff *skb,
 		ttl = ip6_dst_hoplimit(ndst);
 		udp_tunnel6_xmit_skb(ndst, ub->ubsock->sk, skb, NULL,
 				     &src->ipv6, &dst->ipv6, 0, ttl, 0,
-				     src->port, dst->port, false);
+				     src->port, dst->port, false, 0);
 #endif
 	}
 	local_bh_enable();
-- 
2.49.0

Re: [PATCH net-next 06/14] net: ipv6: Add a flags argument to ip6tunnel_xmit(), udp_tunnel6_xmit_skb()

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> ip6tunnel_xmit() erases the contents of the SKB control block. In order to
> be able to set particular IP6CB flags on the SKB, add a corresponding
> parameter, and propagate it to udp_tunnel6_xmit_skb() as well.
> 
> In one of the following patches, VXLAN driver will use this facility to
> mark packets as subject to IPv6 multicast routing.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
> CC:Pablo Neira Ayuso <pablo@netfilter.org>
> CC:osmocom-net-gprs@lists.osmocom.org
> CC:Andrew Lunn <andrew+netdev@lunn.ch>
> CC:Antonio Quartulli <antonio@openvpn.net>
> CC:"Jason A. Donenfeld" <Jason@zx2c4.com>
> CC:wireguard@lists.zx2c4.com
> CC:Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> CC:linux-sctp@vger.kernel.org
> CC:Jon Maloy <jmaloy@redhat.com>
> CC:tipc-discussion@lists.sourceforge.net
> 
>   drivers/net/bareudp.c          | 3 ++-
>   drivers/net/geneve.c           | 3 ++-
>   drivers/net/gtp.c              | 2 +-
>   drivers/net/ovpn/udp.c         | 2 +-
>   drivers/net/vxlan/vxlan_core.c | 3 ++-
>   drivers/net/wireguard/socket.c | 2 +-
>   include/net/ip6_tunnel.h       | 3 ++-
>   include/net/udp_tunnel.h       | 3 ++-
>   net/ipv6/ip6_tunnel.c          | 2 +-
>   net/ipv6/ip6_udp_tunnel.c      | 5 +++--
>   net/sctp/ipv6.c                | 2 +-
>   net/tipc/udp_media.c           | 2 +-
>   12 files changed, 19 insertions(+), 13 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 07/14] net: ipv6: ip6mr: Fix in/out netdev to pass to the FORWARD chain

[Petr Machata]

The netfilter hook is invoked with skb->dev for input netdevice, and
vif_dev for output netdevice. However at the point of invocation, skb->dev
is already set to vif_dev, and MR-forwarded packets are reported with
in=out:

 # ip6tables -A FORWARD -j LOG --log-prefix '[forw]'
 # cd tools/testing/selftests/net/forwarding
 # ./router_multicast.sh
 # dmesg | fgrep '[forw]'
 [ 1670.248245] [forw]IN=v5 OUT=v5 [...]

For reference, IPv4 MR code shows in and out as appropriate.
Fix by caching skb->dev and using the updated value for output netdev.

Fixes: 7bc570c8b4f7 ("[IPV6] MROUTE: Support multicast forwarding.")
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---

Notes:
    This never worked correctly, hence going through net-next.
---
CC: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

 net/ipv6/ip6mr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 3276cde5ebd7..63c90dae6cbf 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2039,6 +2039,7 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
 			  struct sk_buff *skb, int vifi)
 {
 	struct vif_device *vif = &mrt->vif_table[vifi];
+	struct net_device *indev = skb->dev;
 	struct net_device *vif_dev;
 	struct ipv6hdr *ipv6h;
 	struct dst_entry *dst;
@@ -2101,7 +2102,7 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
 	IP6CB(skb)->flags |= IP6SKB_FORWARDED;
 
 	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD,
-		       net, NULL, skb, skb->dev, vif_dev,
+		       net, NULL, skb, indev, skb->dev,
 		       ip6mr_forward2_finish);
 
 out_free:
-- 
2.49.0

Re: [PATCH net-next 07/14] net: ipv6: ip6mr: Fix in/out netdev to pass to the FORWARD chain

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> The netfilter hook is invoked with skb->dev for input netdevice, and
> vif_dev for output netdevice. However at the point of invocation, skb->dev
> is already set to vif_dev, and MR-forwarded packets are reported with
> in=out:
> 
>   # ip6tables -A FORWARD -j LOG --log-prefix '[forw]'
>   # cd tools/testing/selftests/net/forwarding
>   # ./router_multicast.sh
>   # dmesg | fgrep '[forw]'
>   [ 1670.248245] [forw]IN=v5 OUT=v5 [...]
> 
> For reference, IPv4 MR code shows in and out as appropriate.
> Fix by caching skb->dev and using the updated value for output netdev.
> 
> Fixes: 7bc570c8b4f7 ("[IPV6] MROUTE: Support multicast forwarding.")
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
>      This never worked correctly, hence going through net-next.
> ---
> CC: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
> 
>   net/ipv6/ip6mr.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 08/14] net: ipv6: ip6mr: Extract a helper out of ip6mr_forward2()

[Petr Machata]

Some of the work of ip6mr_forward2() is specific to IPMR forwarding, and
should not take place on the output path. In order to allow reuse of the
common parts, extract out of the function a helper,
ip6mr_prepare_forward().

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv6/ip6mr.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 63c90dae6cbf..03bfc0b65175 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2035,11 +2035,10 @@ static inline int ip6mr_forward2_finish(struct net *net, struct sock *sk, struct
  *	Processing handlers for ip6mr_forward
  */
 
-static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
-			  struct sk_buff *skb, int vifi)
+static int ip6mr_prepare_xmit(struct net *net, struct mr_table *mrt,
+			      struct sk_buff *skb, int vifi)
 {
 	struct vif_device *vif = &mrt->vif_table[vifi];
-	struct net_device *indev = skb->dev;
 	struct net_device *vif_dev;
 	struct ipv6hdr *ipv6h;
 	struct dst_entry *dst;
@@ -2098,6 +2097,20 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
 
 	ipv6h = ipv6_hdr(skb);
 	ipv6h->hop_limit--;
+	return 0;
+
+out_free:
+	kfree_skb(skb);
+	return -1;
+}
+
+static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
+			  struct sk_buff *skb, int vifi)
+{
+	struct net_device *indev = skb->dev;
+
+	if (ip6mr_prepare_xmit(net, mrt, skb, vifi))
+		return 0;
 
 	IP6CB(skb)->flags |= IP6SKB_FORWARDED;
 
@@ -2105,9 +2118,6 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
 		       net, NULL, skb, indev, skb->dev,
 		       ip6mr_forward2_finish);
 
-out_free:
-	kfree_skb(skb);
-	return 0;
 }
 
 /* Called with rcu_read_lock() */
-- 
2.49.0

Re: [PATCH net-next 08/14] net: ipv6: ip6mr: Extract a helper out of ip6mr_forward2()

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Some of the work of ip6mr_forward2() is specific to IPMR forwarding, and
> should not take place on the output path. In order to allow reuse of the
> common parts, extract out of the function a helper,
> ip6mr_prepare_forward().
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
>   net/ipv6/ip6mr.c | 22 ++++++++++++++++------
>   1 file changed, 16 insertions(+), 6 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 09/14] net: ipv6: Add ip6_mr_output()

[Petr Machata]

Multicast routing is today handled in the input path. Locally generated MC
packets don't hit the IPMR code today. Thus if a VXLAN remote address is
multicast, the driver needs to set an OIF during route lookup. Thus MC
routing configuration needs to be kept in sync with the VXLAN FDB and MDB.
Ideally, the VXLAN packets would be routed by the MC routing code instead.

To that end, this patch adds support to route locally generated multicast
packets. The newly-added routines do largely what ip6_mr_input() and
ip6_mr_forward() do: make an MR cache lookup to find where to send the
packets, and use ip6_output() to send each of them. When no cache entry is
found, the packet is punted to the daemon for resolution.

Similarly to the IPv4 case in a previous patch, the new logic is contingent
on a newly-added IP6CB flag being set.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 include/linux/ipv6.h    |   1 +
 include/linux/mroute6.h |   7 +++
 net/ipv6/ip6mr.c        | 114 ++++++++++++++++++++++++++++++++++++++++
 net/ipv6/route.c        |   1 +
 4 files changed, 123 insertions(+)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 5aeeed22f35b..db0eb0d86b64 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -156,6 +156,7 @@ struct inet6_skb_parm {
 #define IP6SKB_SEG6	      256
 #define IP6SKB_FAKEJUMBO      512
 #define IP6SKB_MULTIPATH      1024
+#define IP6SKB_MCROUTE        2048
 };
 
 #if defined(CONFIG_NET_L3_MASTER_DEV)
diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h
index 63ef5191cc57..6526787de67e 100644
--- a/include/linux/mroute6.h
+++ b/include/linux/mroute6.h
@@ -31,6 +31,7 @@ extern int ip6_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t);
 extern int ip6_mr_input(struct sk_buff *skb);
 extern int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 extern int ip6_mr_init(void);
+extern int ip6_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb);
 extern void ip6_mr_cleanup(void);
 int ip6mr_ioctl(struct sock *sk, int cmd, void *arg);
 #else
@@ -58,6 +59,12 @@ static inline int ip6_mr_init(void)
 	return 0;
 }
 
+static inline int
+ip6_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	return 0;
+}
+
 static inline void ip6_mr_cleanup(void)
 {
 	return;
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 03bfc0b65175..fa1e3a16851f 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -2120,6 +2120,15 @@ static int ip6mr_forward2(struct net *net, struct mr_table *mrt,
 
 }
 
+static int ip6mr_output2(struct net *net, struct mr_table *mrt,
+			 struct sk_buff *skb, int vifi)
+{
+	if (ip6mr_prepare_xmit(net, mrt, skb, vifi))
+		return 0;
+
+	return ip6_output(net, NULL, skb);
+}
+
 /* Called with rcu_read_lock() */
 static int ip6mr_find_vif(struct mr_table *mrt, struct net_device *dev)
 {
@@ -2232,6 +2241,56 @@ static void ip6_mr_forward(struct net *net, struct mr_table *mrt,
 	kfree_skb(skb);
 }
 
+/* Called under rcu_read_lock() */
+static void ip6_mr_output_finish(struct net *net, struct mr_table *mrt,
+				 struct net_device *dev, struct sk_buff *skb,
+				 struct mfc6_cache *c)
+{
+	int psend = -1;
+	int ct;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	atomic_long_inc(&c->_c.mfc_un.res.pkt);
+	atomic_long_add(skb->len, &c->_c.mfc_un.res.bytes);
+	WRITE_ONCE(c->_c.mfc_un.res.lastuse, jiffies);
+
+	/* Forward the frame */
+	if (ipv6_addr_any(&c->mf6c_origin) &&
+	    ipv6_addr_any(&c->mf6c_mcastgrp)) {
+		if (ipv6_hdr(skb)->hop_limit >
+				c->_c.mfc_un.res.ttls[c->_c.mfc_parent]) {
+			/* It's an (*,*) entry and the packet is not coming from
+			 * the upstream: forward the packet to the upstream
+			 * only.
+			 */
+			psend = c->_c.mfc_parent;
+			goto last_forward;
+		}
+		goto dont_forward;
+	}
+	for (ct = c->_c.mfc_un.res.maxvif - 1;
+	     ct >= c->_c.mfc_un.res.minvif; ct--) {
+		if (ipv6_hdr(skb)->hop_limit > c->_c.mfc_un.res.ttls[ct]) {
+			if (psend != -1) {
+				struct sk_buff *skb2 =
+					skb_clone(skb, GFP_ATOMIC);
+
+				if (skb2)
+					ip6mr_output2(net, mrt, skb2, psend);
+			}
+			psend = ct;
+		}
+	}
+last_forward:
+	if (psend != -1) {
+		ip6mr_output2(net, mrt, skb, psend);
+		return;
+	}
+
+dont_forward:
+	kfree_skb(skb);
+}
 
 /*
  *	Multicast packets for forwarding arrive here
@@ -2299,6 +2358,61 @@ int ip6_mr_input(struct sk_buff *skb)
 	return 0;
 }
 
+int ip6_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct net_device *dev = skb_dst(skb)->dev;
+	struct flowi6 fl6 = (struct flowi6) {
+		.flowi6_iif = LOOPBACK_IFINDEX,
+		.flowi6_mark = skb->mark,
+	};
+	struct mfc6_cache *cache;
+	struct mr_table *mrt;
+	int err;
+	int vif;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	if (IP6CB(skb)->flags & IP6SKB_FORWARDED)
+		goto ip6_output;
+	if (!(IP6CB(skb)->flags & IP6SKB_MCROUTE))
+		goto ip6_output;
+
+	err = ip6mr_fib_lookup(net, &fl6, &mrt);
+	if (err < 0) {
+		kfree_skb(skb);
+		return err;
+	}
+
+	cache = ip6mr_cache_find(mrt,
+				 &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr);
+	if (!cache) {
+		vif = ip6mr_find_vif(mrt, dev);
+		if (vif >= 0)
+			cache = ip6mr_cache_find_any(mrt,
+						     &ipv6_hdr(skb)->daddr,
+						     vif);
+	}
+
+	/* No usable cache entry */
+	if (!cache) {
+		vif = ip6mr_find_vif(mrt, dev);
+		if (vif >= 0)
+			return ip6mr_cache_unresolved(mrt, vif, skb, dev);
+		goto ip6_output;
+	}
+
+	/* Wrong interface */
+	vif = cache->_c.mfc_parent;
+	if (rcu_access_pointer(mrt->vif_table[vif].dev) != dev)
+		goto ip6_output;
+
+	ip6_mr_output_finish(net, mrt, dev, skb, cache);
+	return 0;
+
+ip6_output:
+	return ip6_output(net, sk, skb);
+}
+
 int ip6mr_get_route(struct net *net, struct sk_buff *skb, struct rtmsg *rtm,
 		    u32 portid)
 {
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 0143262094b0..86f88fd8b385 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1145,6 +1145,7 @@ static void ip6_rt_init_dst(struct rt6_info *rt, const struct fib6_result *res)
 		rt->dst.input = ip6_input;
 	} else if (ipv6_addr_type(&f6i->fib6_dst.addr) & IPV6_ADDR_MULTICAST) {
 		rt->dst.input = ip6_mc_input;
+		rt->dst.output = ip6_mr_output;
 	} else {
 		rt->dst.input = ip6_forward;
 	}
-- 
2.49.0

Re: [PATCH net-next 09/14] net: ipv6: Add ip6_mr_output()

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Multicast routing is today handled in the input path. Locally generated MC
> packets don't hit the IPMR code today. Thus if a VXLAN remote address is
> multicast, the driver needs to set an OIF during route lookup. Thus MC
> routing configuration needs to be kept in sync with the VXLAN FDB and MDB.
> Ideally, the VXLAN packets would be routed by the MC routing code instead.
> 
> To that end, this patch adds support to route locally generated multicast
> packets. The newly-added routines do largely what ip6_mr_input() and
> ip6_mr_forward() do: make an MR cache lookup to find where to send the
> packets, and use ip6_output() to send each of them. When no cache entry is
> found, the packet is punted to the daemon for resolution.
> 
> Similarly to the IPv4 case in a previous patch, the new logic is contingent
> on a newly-added IP6CB flag being set.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
>   include/linux/ipv6.h    |   1 +
>   include/linux/mroute6.h |   7 +++
>   net/ipv6/ip6mr.c        | 114 ++++++++++++++++++++++++++++++++++++++++
>   net/ipv6/route.c        |   1 +
>   4 files changed, 123 insertions(+)
> 

Looks good to me,
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 10/14] vxlan: Support MC routing in the underlay

[Petr Machata]

Locally-generated MC packets have so far not been subject to MC routing.
Instead an MC-enabled installation would maintain the MC routing tables,
and separately from that the list of interfaces to send packets to as part
of the VXLAN FDB and MDB.

In a previous patch, a ip_mr_output() and ip6_mr_output() routines were
added for IPv4 and IPv6. All locally generated MC traffic is now passed
through these functions. For reasons of backward compatibility, an SKB
(IPCB / IP6CB) flag guards the actual MC routing.

This patch adds logic to set the flag, and the UAPI to enable the behavior.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---

Notes:
CC:Andrew Lunn <andrew+netdev@lunn.ch>
CC:Menglong Dong <menglong8.dong@gmail.com>

 drivers/net/vxlan/vxlan_core.c | 22 ++++++++++++++++++++--
 include/net/vxlan.h            |  5 ++++-
 include/uapi/linux/if_link.h   |  1 +
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index c4af6c652560..02eba9235406 100644
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -2451,6 +2451,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	rcu_read_lock();
 	if (addr_family == AF_INET) {
 		struct vxlan_sock *sock4 = rcu_dereference(vxlan->vn4_sock);
+		u16 ipcb_flags = 0;
 		struct rtable *rt;
 		__be16 df = 0;
 		__be32 saddr;
@@ -2467,6 +2468,9 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 			goto tx_error;
 		}
 
+		if (flags & VXLAN_F_MC_ROUTE)
+			ipcb_flags |= IPSKB_MCROUTE;
+
 		if (!info) {
 			/* Bypass encapsulation if the destination is local */
 			err = encap_bypass_if_local(skb, dev, vxlan, AF_INET,
@@ -2522,11 +2526,13 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 
 		udp_tunnel_xmit_skb(rt, sock4->sock->sk, skb, saddr,
 				    pkey->u.ipv4.dst, tos, ttl, df,
-				    src_port, dst_port, xnet, !udp_sum, 0);
+				    src_port, dst_port, xnet, !udp_sum,
+				    ipcb_flags);
 #if IS_ENABLED(CONFIG_IPV6)
 	} else {
 		struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
 		struct in6_addr saddr;
+		u16 ip6cb_flags = 0;
 
 		if (!ifindex)
 			ifindex = sock6->sock->sk->sk_bound_dev_if;
@@ -2542,6 +2548,9 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 			goto tx_error;
 		}
 
+		if (flags & VXLAN_F_MC_ROUTE)
+			ip6cb_flags |= IP6SKB_MCROUTE;
+
 		if (!info) {
 			u32 rt6i_flags = dst_rt6_info(ndst)->rt6i_flags;
 
@@ -2587,7 +2596,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		udp_tunnel6_xmit_skb(ndst, sock6->sock->sk, skb, dev,
 				     &saddr, &pkey->u.ipv6.dst, tos, ttl,
 				     pkey->label, src_port, dst_port, !udp_sum,
-				     0);
+				     ip6cb_flags);
 #endif
 	}
 	vxlan_vnifilter_count(vxlan, vni, NULL, VXLAN_VNI_STATS_TX, pkt_len);
@@ -3402,6 +3411,7 @@ static const struct nla_policy vxlan_policy[IFLA_VXLAN_MAX + 1] = {
 	[IFLA_VXLAN_LOCALBYPASS]	= NLA_POLICY_MAX(NLA_U8, 1),
 	[IFLA_VXLAN_LABEL_POLICY]       = NLA_POLICY_MAX(NLA_U32, VXLAN_LABEL_MAX),
 	[IFLA_VXLAN_RESERVED_BITS] = NLA_POLICY_EXACT_LEN(sizeof(struct vxlanhdr)),
+	[IFLA_VXLAN_MC_ROUTE]		= NLA_POLICY_MAX(NLA_U8, 1),
 };
 
 static int vxlan_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -4315,6 +4325,14 @@ static int vxlan_nl2conf(struct nlattr *tb[], struct nlattr *data[],
 			return err;
 	}
 
+	if (data[IFLA_VXLAN_MC_ROUTE]) {
+		err = vxlan_nl2flag(conf, data, IFLA_VXLAN_MC_ROUTE,
+				    VXLAN_F_MC_ROUTE, changelink,
+				    true, extack);
+		if (err)
+			return err;
+	}
+
 	if (tb[IFLA_MTU]) {
 		if (changelink) {
 			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_MTU],
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index e2f7ca045d3e..0ee50785f4f1 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -332,6 +332,7 @@ struct vxlan_dev {
 #define VXLAN_F_VNIFILTER               0x20000
 #define VXLAN_F_MDB			0x40000
 #define VXLAN_F_LOCALBYPASS		0x80000
+#define VXLAN_F_MC_ROUTE		0x100000
 
 /* Flags that are used in the receive path. These flags must match in
  * order for a socket to be shareable
@@ -353,7 +354,9 @@ struct vxlan_dev {
 					 VXLAN_F_UDP_ZERO_CSUM6_RX |	\
 					 VXLAN_F_COLLECT_METADATA  |	\
 					 VXLAN_F_VNIFILTER         |    \
-					 VXLAN_F_LOCALBYPASS)
+					 VXLAN_F_LOCALBYPASS       |	\
+					 VXLAN_F_MC_ROUTE          |	\
+					 0)
 
 struct net_device *vxlan_dev_create(struct net *net, const char *name,
 				    u8 name_assign_type, struct vxlan_config *conf);
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 3ad2d5d98034..873c285996fe 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1398,6 +1398,7 @@ enum {
 	IFLA_VXLAN_LOCALBYPASS,
 	IFLA_VXLAN_LABEL_POLICY, /* IPv6 flow label policy; ifla_vxlan_label_policy */
 	IFLA_VXLAN_RESERVED_BITS,
+	IFLA_VXLAN_MC_ROUTE,
 	__IFLA_VXLAN_MAX
 };
 #define IFLA_VXLAN_MAX	(__IFLA_VXLAN_MAX - 1)
-- 
2.49.0

Re: [PATCH net-next 10/14] vxlan: Support MC routing in the underlay

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Locally-generated MC packets have so far not been subject to MC routing.
> Instead an MC-enabled installation would maintain the MC routing tables,
> and separately from that the list of interfaces to send packets to as part
> of the VXLAN FDB and MDB.
> 
> In a previous patch, a ip_mr_output() and ip6_mr_output() routines were
> added for IPv4 and IPv6. All locally generated MC traffic is now passed
> through these functions. For reasons of backward compatibility, an SKB
> (IPCB / IP6CB) flag guards the actual MC routing.
> 
> This patch adds logic to set the flag, and the UAPI to enable the behavior.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
> 
> Notes:
> CC:Andrew Lunn <andrew+netdev@lunn.ch>
> CC:Menglong Dong <menglong8.dong@gmail.com>
> 
>   drivers/net/vxlan/vxlan_core.c | 22 ++++++++++++++++++++--
>   include/net/vxlan.h            |  5 ++++-
>   include/uapi/linux/if_link.h   |  1 +
>   3 files changed, 25 insertions(+), 3 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 11/14] selftests: forwarding: lib: Move smcrouted helpers here

[Petr Machata]

router_multicast.sh has several helpers for work with smcrouted. Extract
them to lib.sh so that other selftests can use them as well. Convert the
helpers to defer in the process, because that simplifies the interface
quite a bit. Therefore have router_multicast.sh invoke
defer_scopes_cleanup() in its cleanup() function.

Signed-off-by: Petr Machata <petrm@nvidia.com>
---

Notes:
CC: Shuah Khan <shuah@kernel.org>
CC: linux-kselftest@vger.kernel.org

 tools/testing/selftests/net/forwarding/lib.sh | 31 +++++++++++++++++++
 .../net/forwarding/router_multicast.sh        | 31 +++----------------
 2 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 508f3c700d71..88e63562f5c5 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -37,6 +37,7 @@ declare -A NETIFS=(
 : "${TEAMD:=teamd}"
 : "${MCD:=smcrouted}"
 : "${MC_CLI:=smcroutectl}"
+: "${MCD_TABLE_NAME:=selftests}"
 
 # Constants for netdevice bring-up:
 # Default time in seconds to wait for an interface to come up before giving up
@@ -1757,6 +1758,36 @@ mc_send()
 		msend -g $groups -I $if_name -c 1 > /dev/null 2>&1
 }
 
+adf_mcd_start()
+{
+	local i
+
+	check_command $MCD || return 1
+	check_command $MC_CLI || return 1
+
+	local table_name="$MCD_TABLE_NAME"
+	local smcroutedir="$(mktemp -d)"
+
+	defer rm -rf $smcroutedir
+
+	for ((i = 1; i <= $NUM_NETIFS; ++i)); do
+		echo "phyint ${NETIFS[p$i]} enable" >> \
+			$smcroutedir/$table_name.conf
+	done
+
+	$MCD -N -I $table_name -f $smcroutedir/$table_name.conf \
+		-P $smcroutedir/$table_name.pid
+	busywait "$BUSYWAIT_TIMEOUT" test -e $smcroutedir/$table_name.pid
+	defer kill_process $(cat $smcroutedir/$table_name.pid)
+}
+
+mc_cli()
+{
+	local table_name="$MCD_TABLE_NAME"
+
+        $MC_CLI -I $table_name "$@"
+}
+
 start_ip_monitor()
 {
 	local mtype=$1; shift
diff --git a/tools/testing/selftests/net/forwarding/router_multicast.sh b/tools/testing/selftests/net/forwarding/router_multicast.sh
index 5a58b1ec8aef..1e2378777b48 100755
--- a/tools/testing/selftests/net/forwarding/router_multicast.sh
+++ b/tools/testing/selftests/net/forwarding/router_multicast.sh
@@ -33,10 +33,6 @@ NUM_NETIFS=6
 source lib.sh
 source tc_common.sh
 
-require_command $MCD
-require_command $MC_CLI
-table_name=selftests
-
 h1_create()
 {
 	simple_if_init $h1 198.51.100.2/28 2001:db8:1::2/64
@@ -149,25 +145,6 @@ router_destroy()
 	ip link set dev $rp1 down
 }
 
-start_mcd()
-{
-	SMCROUTEDIR="$(mktemp -d)"
-
-	for ((i = 1; i <= $NUM_NETIFS; ++i)); do
-		echo "phyint ${NETIFS[p$i]} enable" >> \
-			$SMCROUTEDIR/$table_name.conf
-	done
-
-	$MCD -N -I $table_name -f $SMCROUTEDIR/$table_name.conf \
-		-P $SMCROUTEDIR/$table_name.pid
-}
-
-kill_mcd()
-{
-	pkill $MCD
-	rm -rf $SMCROUTEDIR
-}
-
 setup_prepare()
 {
 	h1=${NETIFS[p1]}
@@ -179,7 +156,7 @@ setup_prepare()
 	rp3=${NETIFS[p5]}
 	h3=${NETIFS[p6]}
 
-	start_mcd
+	adf_mcd_start || exit $EXIT_STATUS
 
 	vrf_prepare
 
@@ -206,7 +183,7 @@ cleanup()
 
 	vrf_cleanup
 
-	kill_mcd
+	defer_scopes_cleanup
 }
 
 create_mcast_sg()
@@ -216,7 +193,7 @@ create_mcast_sg()
 	local mcast=$1; shift
 	local dest_ifs=${@}
 
-	$MC_CLI -I $table_name add $if_name $s_addr $mcast $dest_ifs
+	mc_cli add $if_name $s_addr $mcast $dest_ifs
 }
 
 delete_mcast_sg()
@@ -226,7 +203,7 @@ delete_mcast_sg()
 	local mcast=$1; shift
 	local dest_ifs=${@}
 
-        $MC_CLI -I $table_name remove $if_name $s_addr $mcast $dest_ifs
+        mc_cli remove $if_name $s_addr $mcast $dest_ifs
 }
 
 mcast_v4()
-- 
2.49.0

Re: [PATCH net-next 11/14] selftests: forwarding: lib: Move smcrouted helpers here

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> router_multicast.sh has several helpers for work with smcrouted. Extract
> them to lib.sh so that other selftests can use them as well. Convert the
> helpers to defer in the process, because that simplifies the interface
> quite a bit. Therefore have router_multicast.sh invoke
> defer_scopes_cleanup() in its cleanup() function.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> ---
> 
> Notes:
> CC: Shuah Khan <shuah@kernel.org>
> CC: linux-kselftest@vger.kernel.org
> 
>   tools/testing/selftests/net/forwarding/lib.sh | 31 +++++++++++++++++++
>   .../net/forwarding/router_multicast.sh        | 31 +++----------------
>   2 files changed, 35 insertions(+), 27 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 12/14] selftests: net: lib: Add ip_link_has_flag()

[Petr Machata]

Add a helper to determine whether a given netdevice has a given flag.

Rewrite ip_link_is_up() in terms of the new helper.

Signed-off-by: Petr Machata <petrm@nvidia.com>
---

Notes:
CC: Shuah Khan <shuah@kernel.org>
CC: linux-kselftest@vger.kernel.org

 tools/testing/selftests/net/lib.sh | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
index 006fdadcc4b9..ff0dbe23e8e0 100644
--- a/tools/testing/selftests/net/lib.sh
+++ b/tools/testing/selftests/net/lib.sh
@@ -547,13 +547,19 @@ ip_link_set_addr()
 	defer ip link set dev "$name" address "$old_addr"
 }
 
-ip_link_is_up()
+ip_link_has_flag()
 {
 	local name=$1; shift
+	local flag=$1; shift
 
 	local state=$(ip -j link show "$name" |
-		      jq -r '(.[].flags[] | select(. == "UP")) // "DOWN"')
-	[[ $state == "UP" ]]
+		      jq --arg flag "$flag" 'any(.[].flags.[]; . == $flag)')
+	[[ $state == true ]]
+}
+
+ip_link_is_up()
+{
+	ip_link_has_flag "$1" UP
 }
 
 ip_link_set_up()
-- 
2.49.0

Re: [PATCH net-next 12/14] selftests: net: lib: Add ip_link_has_flag()

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Add a helper to determine whether a given netdevice has a given flag.
> 
> Rewrite ip_link_is_up() in terms of the new helper.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> ---
> 
> Notes:
> CC: Shuah Khan <shuah@kernel.org>
> CC: linux-kselftest@vger.kernel.org
> 
>   tools/testing/selftests/net/lib.sh | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 13/14] selftests: forwarding: adf_mcd_start(): Allow configuring custom interfaces

[Petr Machata]

Tests may wish to add other interfaces to listen on. Notably locally
generated traffic uses dummy interfaces. The multicast daemon needs to know
about these so that it allows forming rules that involve these interfaces,
and so that net.ipv4.conf.X.mc_forwarding is set for the interfaces.

To that end, allow passing in a list of interfaces to configure in addition
to all the physical ones.

Signed-off-by: Petr Machata <petrm@nvidia.com>
---

Notes:
CC: Shuah Khan <shuah@kernel.org>
CC: linux-kselftest@vger.kernel.org

 tools/testing/selftests/net/forwarding/lib.sh | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 88e63562f5c5..5f144d75167a 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -1760,6 +1760,8 @@ mc_send()
 
 adf_mcd_start()
 {
+	local ifs=("$@")
+	local if
 	local i
 
 	check_command $MCD || return 1
@@ -1775,6 +1777,16 @@ adf_mcd_start()
 			$smcroutedir/$table_name.conf
 	done
 
+	for if in ${ifs[@]}; do
+		if ! ip_link_has_flag "$if" MULTICAST; then
+			ip link set dev "$if" multicast on
+			defer ip link set dev "$if" multicast off
+		fi
+
+		echo "phyint $if enable" >> \
+			$smcroutedir/$table_name.conf
+	done
+
 	$MCD -N -I $table_name -f $smcroutedir/$table_name.conf \
 		-P $smcroutedir/$table_name.pid
 	busywait "$BUSYWAIT_TIMEOUT" test -e $smcroutedir/$table_name.pid
-- 
2.49.0

Re: [PATCH net-next 13/14] selftests: forwarding: adf_mcd_start(): Allow configuring custom interfaces

[Nikolay Aleksandrov]

On 6/9/25 23:50, Petr Machata wrote:
> Tests may wish to add other interfaces to listen on. Notably locally
> generated traffic uses dummy interfaces. The multicast daemon needs to know
> about these so that it allows forming rules that involve these interfaces,
> and so that net.ipv4.conf.X.mc_forwarding is set for the interfaces.
> 
> To that end, allow passing in a list of interfaces to configure in addition
> to all the physical ones.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> ---
> 
> Notes:
> CC: Shuah Khan <shuah@kernel.org>
> CC: linux-kselftest@vger.kernel.org
> 
>   tools/testing/selftests/net/forwarding/lib.sh | 12 ++++++++++++
>   1 file changed, 12 insertions(+)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next 14/14] selftests: forwarding: Add a test for verifying VXLAN MC underlay

[Petr Machata]

Add tests for MC-routing underlay VXLAN traffic.

Signed-off-by: Petr Machata <petrm@nvidia.com>
---

Notes:
CC: Shuah Khan <shuah@kernel.org>
CC: linux-kselftest@vger.kernel.org

 .../testing/selftests/net/forwarding/Makefile |   1 +
 .../net/forwarding/vxlan_bridge_1q_mc_ul.sh   | 757 ++++++++++++++++++
 2 files changed, 758 insertions(+)
 create mode 100755 tools/testing/selftests/net/forwarding/vxlan_bridge_1q_mc_ul.sh

diff --git a/tools/testing/selftests/net/forwarding/Makefile b/tools/testing/selftests/net/forwarding/Makefile
index 00bde7b6f39e..d7bb2e80e88c 100644
--- a/tools/testing/selftests/net/forwarding/Makefile
+++ b/tools/testing/selftests/net/forwarding/Makefile
@@ -102,6 +102,7 @@ TEST_PROGS = bridge_fdb_learning_limit.sh \
 	vxlan_bridge_1d_port_8472.sh \
 	vxlan_bridge_1d.sh \
 	vxlan_bridge_1q_ipv6.sh \
+	vxlan_bridge_1q_mc_ul.sh \
 	vxlan_bridge_1q_port_8472_ipv6.sh \
 	vxlan_bridge_1q_port_8472.sh \
 	vxlan_bridge_1q.sh \
diff --git a/tools/testing/selftests/net/forwarding/vxlan_bridge_1q_mc_ul.sh b/tools/testing/selftests/net/forwarding/vxlan_bridge_1q_mc_ul.sh
new file mode 100755
index 000000000000..e01e7ccf2c8d
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/vxlan_bridge_1q_mc_ul.sh
@@ -0,0 +1,757 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# +-----------------------------------------+
+# | + $h1.10             + $h1.20           |
+# | | 192.0.2.1/28       | 2001:db8:1::1/64 |
+# | \________   ________/                   |
+# |          \ /                            |
+# |           + $h1                H1 (vrf) |
+# +-----------|-----------------------------+
+#             |
+# +-----------|----------------------------------------------------------------+
+# | +---------|--------------------------------------+       SWITCH (main vrf) |
+# | |         + $swp1                   BR1 (802.1q) |                         |
+# | |            vid 10 20                           |                         |
+# | |                                                |                         |
+# | |  + vx10 (vxlan)         + vx20 (vxlan)         |      + lo10 (dummy)     |
+# | |    local 192.0.2.100      local 2001:db8:4::1  |        192.0.2.100/28   |
+# | |    group 233.252.0.1      group ff0e::1:2:3    |        2001:db8:4::1/64 |
+# | |    id 1000                id 2000              |                         |
+# | |    vid 10 pvid untagged   vid 20 pvid untagged |                         |
+# | +------------------------------------------------+                         |
+# |                                                                            |
+# |   + $swp2                                                        $swp3 +   |
+# |   | 192.0.2.33/28                                        192.0.2.65/28 |   |
+# |   | 2001:db8:2::1/64                                  2001:db8:3::1/64 |   |
+# |   |                                                                    |   |
+# +---|--------------------------------------------------------------------|---+
+#     |                                                                    |
+# +---|--------------------------------+  +--------------------------------|---+
+# |   |                      H2 (vrf)  |  | H3 (vrf)                       |   |
+# | +-|----------------------------+   |  |  +-----------------------------|-+ |
+# | | + $h2           BR2 (802.1d) |   |  |  | BR3 (802.1d)            $h3 + | |
+# | |                              |   |  |  |                               | |
+# | | + v1$h2 (veth)               |   |  |  |                v1$h3 (veth) + | |
+# | +-|----------------------------+   |  |  +-----------------------------|-+ |
+# |   |                                |  |                                |   |
+# +---|--------------------------------+  +--------------------------------|---+
+#     |                                                                    |
+# +---|--------------------------------+  +--------------------------------|---+
+# |   + v2$h2 (veth)       NS2 (netns) |  | NS3 (netns)       v2$h3 (veth) +   |
+# |     192.0.2.34/28                  |  |                  192.0.2.66/28     |
+# |     2001:db8:2::2/64               |  |               2001:db8:3::2/64     |
+# |                                    |  |                                    |
+# | +--------------------------------+ |  | +--------------------------------+ |
+# | |                  BR1 (802.1q)  | |  | |                   BR1 (802.1q) | |
+# | |  + vx10 (vxlan)                | |  | |  + vx10 (vxlan)                | |
+# | |    local 192.0.2.34            | |  | |    local 192.0.2.50            | |
+# | |    group 233.252.0.1 dev v2$h2 | |  | |    group 233.252.0.1 dev v2$h3 | |
+# | |    id 1000 dstport $VXPORT     | |  | |    id 1000 dstport $VXPORT     | |
+# | |    vid 10 pvid untagged        | |  | |    vid 10 pvid untagged        | |
+# | |                                | |  | |                                | |
+# | |  + vx20 (vxlan)                | |  | |  + vx20 (vxlan)                | |
+# | |    local 2001:db8:2::2         | |  | |    local 2001:db8:3::2         | |
+# | |    group ff0e::1:2:3 dev v2$h2 | |  | |    group ff0e::1:2:3 dev v2$h3 | |
+# | |    id 2000 dstport $VXPORT     | |  | |    id 2000 dstport $VXPORT     | |
+# | |    vid 20 pvid untagged        | |  | |    vid 20 pvid untagged        | |
+# | |                                | |  | |                                | |
+# | |  + w1 (veth)                   | |  | |  + w1 (veth)                   | |
+# | |  | vid 10 20                   | |  | |  | vid 10 20                   | |
+# | +--|-----------------------------+ |  | +--|-----------------------------+ |
+# |    |                               |  |    |                               |
+# | +--|-----------------------------+ |  | +--|-----------------------------+ |
+# | |  + w2 (veth)        VW2 (vrf)  | |  | |  + w2 (veth)        VW2 (vrf)  | |
+# | |  |\                            | |  | |  |\                            | |
+# | |  | + w2.10                     | |  | |  | + w2.10                     | |
+# | |  |   192.0.2.3/28              | |  | |  |   192.0.2.4/28              | |
+# | |  |                             | |  | |  |                             | |
+# | |  + w2.20                       | |  | |  + w2.20                       | |
+# | |    2001:db8:1::3/64            | |  | |    2001:db8:1::4/64            | |
+# | +--------------------------------+ |  | +--------------------------------+ |
+# +------------------------------------+  +------------------------------------+
+
+: "${VXPORT:=4789}"
+export VXPORT
+
+: "${GROUP4:=233.252.0.1}"
+export GROUP4
+
+: "${GROUP6:=ff0e::1:2:3}"
+export GROUP6
+
+: "${IPMR:=lo10}"
+
+ALL_TESTS="
+	ipv4_nomcroute
+	ipv4_mcroute
+	ipv4_mcroute_changelink
+	ipv4_mcroute_starg
+	ipv4_mcroute_noroute
+	ipv4_mcroute_fdb
+	ipv4_mcroute_fdb_oif0
+	ipv4_mcroute_fdb_oif0_sep
+
+	ipv6_nomcroute
+	ipv6_mcroute
+	ipv6_mcroute_changelink
+	ipv6_mcroute_starg
+	ipv6_mcroute_noroute
+	ipv6_mcroute_fdb
+	ipv6_mcroute_fdb_oif0
+
+	ipv4_nomcroute_rx
+	ipv4_mcroute_rx
+	ipv4_mcroute_starg_rx
+	ipv4_mcroute_fdb_oif0_sep_rx
+	ipv4_mcroute_fdb_sep_rx
+
+	ipv6_nomcroute_rx
+	ipv6_mcroute_rx
+	ipv6_mcroute_starg_rx
+	ipv6_mcroute_fdb_sep_rx
+"
+
+NUM_NETIFS=6
+source lib.sh
+
+h1_create()
+{
+	simple_if_init $h1
+	defer simple_if_fini $h1
+
+	ip_link_add $h1.10 master v$h1 link $h1 type vlan id 10
+	ip_link_set_up $h1.10
+	ip_addr_add $h1.10 192.0.2.1/28
+
+	ip_link_add $h1.20 master v$h1 link $h1 type vlan id 20
+	ip_link_set_up $h1.20
+	ip_addr_add $h1.20 2001:db8:1::1/64
+}
+
+install_capture()
+{
+	local dev=$1; shift
+
+	tc qdisc add dev $dev clsact
+	defer tc qdisc del dev $dev clsact
+
+	tc filter add dev $dev ingress proto ip pref 104 \
+	   flower skip_hw ip_proto udp dst_port $VXPORT \
+	   action pass
+	defer tc filter del dev $dev ingress proto ip pref 104
+
+	tc filter add dev $dev ingress proto ipv6 pref 106 \
+	   flower skip_hw ip_proto udp dst_port $VXPORT \
+	   action pass
+	defer tc filter del dev $dev ingress proto ipv6 pref 106
+}
+
+h2_create()
+{
+	# $h2
+	ip_link_set_up $h2
+
+	# H2
+	vrf_create v$h2
+	defer vrf_destroy v$h2
+
+	ip_link_set_up v$h2
+
+	# br2
+	ip_link_add br2 type bridge vlan_filtering 0 mcast_snooping 0
+	ip_link_set_master br2 v$h2
+	ip_link_set_up br2
+
+	# $h2
+	ip_link_set_master $h2 br2
+	install_capture $h2
+
+	# v1$h2
+	ip_link_set_up v1$h2
+	ip_link_set_master v1$h2 br2
+}
+
+h3_create()
+{
+	# $h3
+	ip_link_set_up $h3
+
+	# H3
+	vrf_create v$h3
+	defer vrf_destroy v$h3
+
+	ip_link_set_up v$h3
+
+	# br3
+	ip_link_add br3 type bridge vlan_filtering 0 mcast_snooping 0
+	ip_link_set_master br3 v$h3
+	ip_link_set_up br3
+
+	# $h3
+	ip_link_set_master $h3 br3
+	install_capture $h3
+
+	# v1$h3
+	ip_link_set_up v1$h3
+	ip_link_set_master v1$h3 br3
+}
+
+switch_create()
+{
+	# br1
+	ip_link_add br1 type bridge vlan_filtering 1 \
+			    vlan_default_pvid 0 mcast_snooping 0
+	ip_link_set_addr br1 $(mac_get $swp1)
+	ip_link_set_up br1
+
+	# A dummy to force the IPv6 OIF=0 test to install a suitable MC route on
+	# $IPMR to be deterministic. Also used for the IPv6 RX!=TX ping test.
+	ip_link_add "X$IPMR" up type dummy
+
+	# IPMR
+	ip_link_add "$IPMR" up type dummy
+	ip_addr_add "$IPMR" 192.0.2.100/28
+	ip_addr_add "$IPMR" 2001:db8:4::1/64
+
+	# $swp1
+	ip_link_set_up $swp1
+	ip_link_set_master $swp1 br1
+	bridge_vlan_add vid 10 dev $swp1
+	bridge_vlan_add vid 20 dev $swp1
+
+	# $swp2
+	ip_link_set_up $swp2
+	ip_addr_add $swp2 192.0.2.33/28
+	ip_addr_add $swp2 2001:db8:2::1/64
+
+	# $swp3
+	ip_link_set_up $swp3
+	ip_addr_add $swp3 192.0.2.65/28
+	ip_addr_add $swp3 2001:db8:3::1/64
+}
+
+vx_create()
+{
+	local name=$1; shift
+	local vid=$1; shift
+
+	ip_link_add "$name" up type vxlan dstport "$VXPORT" \
+		nolearning noudpcsum tos inherit ttl 16 \
+		"$@"
+	ip_link_set_master "$name" br1
+	bridge_vlan_add vid $vid dev "$name" pvid untagged
+}
+export -f vx_create
+
+vx_wait()
+{
+	# Wait for all the ARP, IGMP etc. noise to settle down so that the
+	# tunnel is clear for measurements.
+	sleep 10
+}
+
+vx10_create()
+{
+	vx_create vx10 10 id 1000 "$@"
+}
+export -f vx10_create
+
+vx20_create()
+{
+	vx_create vx20 20 id 2000 "$@"
+}
+export -f vx20_create
+
+vx10_create_wait()
+{
+	vx10_create "$@"
+	vx_wait
+}
+
+vx20_create_wait()
+{
+	vx20_create "$@"
+	vx_wait
+}
+
+ns_init_common()
+{
+	local ns=$1; shift
+	local if_in=$1; shift
+	local ipv4_in=$1; shift
+	local ipv6_in=$1; shift
+	local ipv4_host=$1; shift
+	local ipv6_host=$1; shift
+
+	# v2$h2 / v2$h3
+	ip_link_set_up $if_in
+	ip_addr_add $if_in $ipv4_in
+	ip_addr_add $if_in $ipv6_in
+
+	# br1
+	ip_link_add br1 type bridge vlan_filtering 1 \
+		    vlan_default_pvid 0 mcast_snooping 0
+	ip_link_set_up br1
+
+	# vx10, vx20
+	vx10_create local ${ipv4_in%/*} group $GROUP4 dev $if_in
+	vx20_create local ${ipv6_in%/*} group $GROUP6 dev $if_in
+
+	# w1
+	ip_link_add w1 type veth peer name w2
+	ip_link_set_master w1 br1
+	ip_link_set_up w1
+	bridge_vlan_add vid 10 dev w1
+	bridge_vlan_add vid 20 dev w1
+
+	# w2
+	simple_if_init w2
+	defer simple_if_fini w2
+
+	# w2.10
+	ip_link_add w2.10 master vw2 link w2 type vlan id 10
+	ip_link_set_up w2.10
+	ip_addr_add w2.10 $ipv4_host
+
+	# w2.20
+	ip_link_add w2.20 master vw2 link w2 type vlan id 20
+	ip_link_set_up w2.20
+	ip_addr_add w2.20 $ipv6_host
+}
+export -f ns_init_common
+
+ns2_create()
+{
+	# NS2
+	ip netns add ns2
+	defer ip netns del ns2
+
+	# v2$h2
+	ip link set dev v2$h2 netns ns2
+	defer ip -n ns2 link set dev v2$h2 netns 1
+
+	in_ns ns2 \
+	      ns_init_common ns2 v2$h2 \
+			     192.0.2.34/28 2001:db8:2::2/64 \
+			     192.0.2.3/28  2001:db8:1::3/64
+}
+
+ns3_create()
+{
+	# NS3
+	ip netns add ns3
+	defer ip netns del ns3
+
+	# v2$h3
+	ip link set dev v2$h3 netns ns3
+	defer ip -n ns3 link set dev v2$h3 netns 1
+
+	ip -n ns3 link set dev v2$h3 up
+
+	in_ns ns3 \
+	      ns_init_common ns3 v2$h3 \
+			     192.0.2.66/28 2001:db8:3::2/64 \
+			     192.0.2.4/28  2001:db8:1::4/64
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	swp1=${NETIFS[p2]}
+
+	swp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	swp3=${NETIFS[p5]}
+	h3=${NETIFS[p6]}
+
+	vrf_prepare
+	defer vrf_cleanup
+
+	forwarding_enable
+	defer forwarding_restore
+
+	ip_link_add v1$h2 type veth peer name v2$h2
+	ip_link_add v1$h3 type veth peer name v2$h3
+
+	h1_create
+	h2_create
+	h3_create
+	switch_create
+	ns2_create
+	ns3_create
+}
+
+adf_install_broken_sg()
+{
+	adf_mcd_start "$IPMR" || exit $EXIT_STATUS
+
+	mc_cli add $swp2 192.0.2.100 $GROUP4 $swp1 $swp3
+	defer mc_cli remove $swp2 192.0.2.100 $GROUP4 $swp1 $swp3
+
+	mc_cli add $swp2 2001:db8:4::1 $GROUP6 $swp1 $swp3
+	defer mc_cli remove $swp2 2001:db8:4::1 $GROUP6 $swp1 $swp3
+}
+
+adf_install_rx()
+{
+	mc_cli add $swp2 0.0.0.0 $GROUP4 "$IPMR"
+	defer mc_cli remove $swp2 0.0.0.0 $GROUP4 lo10
+
+	mc_cli add $swp3 0.0.0.0 $GROUP4 "$IPMR"
+	defer mc_cli remove $swp3 0.0.0.0 $GROUP4 lo10
+
+	mc_cli add $swp2 :: $GROUP6 "$IPMR"
+	defer mc_cli remove $swp2 :: $GROUP6 lo10
+
+	mc_cli add $swp3 :: $GROUP6 "$IPMR"
+	defer mc_cli remove $swp3 :: $GROUP6 lo10
+}
+
+adf_install_sg()
+{
+	adf_mcd_start "$IPMR" || exit $EXIT_STATUS
+
+	mc_cli add "$IPMR" 192.0.2.100 $GROUP4 $swp2 $swp3
+	defer mc_cli remove "$IPMR" 192.0.2.33 $GROUP4 $swp2 $swp3
+
+	mc_cli add "$IPMR" 2001:db8:4::1 $GROUP6 $swp2 $swp3
+	defer mc_cli remove "$IPMR" 2001:db8:4::1 $GROUP6 $swp2 $swp3
+
+	adf_install_rx
+}
+
+adf_install_sg_sep()
+{
+	adf_mcd_start lo || exit $EXIT_STATUS
+
+	mc_cli add lo 192.0.2.120 $GROUP4 $swp2 $swp3
+	defer mc_cli remove lo 192.0.2.120 $GROUP4 $swp2 $swp3
+
+	mc_cli add lo 2001:db8:5::1 $GROUP6 $swp2 $swp3
+	defer mc_cli remove lo 2001:db8:5::1 $GROUP6 $swp2 $swp3
+}
+
+adf_install_sg_sep_rx()
+{
+	local lo=$1; shift
+
+	adf_mcd_start "$IPMR" "$lo" || exit $EXIT_STATUS
+
+	mc_cli add "$lo" 192.0.2.120 $GROUP4 $swp2 $swp3
+	defer mc_cli remove "$lo" 192.0.2.120 $GROUP4 $swp2 $swp3
+
+	mc_cli add "$lo" 2001:db8:5::1 $GROUP6 $swp2 $swp3
+	defer mc_cli remove "$lo" 2001:db8:5::1 $GROUP6 $swp2 $swp3
+
+	adf_install_rx
+}
+
+adf_install_starg()
+{
+	adf_mcd_start "$IPMR" || exit $EXIT_STATUS
+
+	mc_cli add "$IPMR" 0.0.0.0 $GROUP4 $swp2 $swp3
+	defer mc_cli remove "$IPMR" 0.0.0.0 $GROUP4 $swp2 $swp3
+
+	mc_cli add "$IPMR" :: $GROUP6 $swp2 $swp3
+	defer mc_cli remove "$IPMR" :: $GROUP6 $swp2 $swp3
+
+	adf_install_rx
+}
+
+do_packets_v4()
+{
+	local mac=$(mac_get $h2)
+
+	$MZ $h1 -Q 10 -c 10 -d 100msec -p 64 -a own -b $mac \
+	    -A 192.0.2.1 -B 192.0.2.2 -t udp sp=1234,dp=2345 -q
+}
+
+do_packets_v6()
+{
+	local mac=$(mac_get $h2)
+
+	$MZ -6 $h1 -Q 20 -c 10 -d 100msec -p 64 -a own -b $mac \
+	    -A 2001:db8:1::1 -B 2001:db8:1::2 -t udp sp=1234,dp=2345 -q
+}
+
+do_test()
+{
+	local ipv=$1; shift
+	local expect_h2=$1; shift
+	local expect_h3=$1; shift
+	local what=$1; shift
+
+	local pref=$((100 + ipv))
+
+	RET=0
+
+	local t0_h2=$(tc_rule_stats_get $h2 $pref ingress)
+	local t0_h3=$(tc_rule_stats_get $h3 $pref ingress)
+
+	do_packets_v$ipv
+	sleep 1
+
+	local t1_h2=$(tc_rule_stats_get $h2 $pref ingress)
+	local t1_h3=$(tc_rule_stats_get $h3 $pref ingress)
+
+	local d_h2=$((t1_h2 - t0_h2))
+	local d_h3=$((t1_h3 - t0_h3))
+
+	((d_h2 == expect_h2))
+	check_err $? "Expected $expect_h2 packets on H2, got $d_h2"
+
+	((d_h3 == expect_h3))
+	check_err $? "Expected $expect_h3 packets on H3, got $d_h3"
+
+	log_test "VXLAN MC flood $what"
+}
+
+ipv4_do_test_rx()
+{
+	local h3_should_fail=$1; shift
+	local what=$1; shift
+
+	RET=0
+
+	ping_do $h1.10 192.0.2.3
+	check_err $? "H2 should respond"
+
+	ping_do $h1.10 192.0.2.4
+	check_err_fail $h3_should_fail $? "H3 responds"
+
+	log_test "VXLAN MC flood $what"
+}
+
+ipv6_do_test_rx()
+{
+	local h3_should_fail=$1; shift
+	local what=$1; shift
+
+	RET=0
+
+	ping6_do $h1.20 2001:db8:1::3
+	check_err $? "H2 should respond"
+
+	ping6_do $h1.20 2001:db8:1::4
+	check_err_fail $h3_should_fail $? "H3 responds"
+
+	log_test "VXLAN MC flood $what"
+}
+
+ipv4_nomcroute()
+{
+	# Install a misleading (S,G) rule to attempt to trick the system into
+	# pushing the packets elsewhere.
+	adf_install_broken_sg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$swp2"
+	do_test 4 10 0 "IPv4 nomcroute"
+}
+
+ipv6_nomcroute()
+{
+	# Like for IPv4, install a misleading (S,G).
+	adf_install_broken_sg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$swp2"
+	do_test 6 10 0 "IPv6 nomcroute"
+}
+
+ipv4_nomcroute_rx()
+{
+	vx10_create local 192.0.2.100 group $GROUP4 dev "$swp2"
+	ipv4_do_test_rx 1 "IPv4 nomcroute ping"
+}
+
+ipv6_nomcroute_rx()
+{
+	vx20_create local 2001:db8:4::1 group $GROUP6 dev "$swp2"
+	ipv6_do_test_rx 1 "IPv6 nomcroute ping"
+}
+
+ipv4_mcroute()
+{
+	adf_install_sg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	do_test 4 10 10 "IPv4 mcroute"
+}
+
+ipv6_mcroute()
+{
+	adf_install_sg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	do_test 6 10 10 "IPv6 mcroute"
+}
+
+ipv4_mcroute_rx()
+{
+	adf_install_sg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	ipv4_do_test_rx 0 "IPv4 mcroute ping"
+}
+
+ipv6_mcroute_rx()
+{
+	adf_install_sg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	ipv6_do_test_rx 0 "IPv6 mcroute ping"
+}
+
+ipv4_mcroute_changelink()
+{
+	adf_install_sg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR"
+	ip link set dev vx10 type vxlan mcroute
+	sleep 1
+	do_test 4 10 10 "IPv4 mcroute changelink"
+}
+
+ipv6_mcroute_changelink()
+{
+	adf_install_sg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	ip link set dev vx20 type vxlan mcroute
+	sleep 1
+	do_test 6 10 10 "IPv6 mcroute changelink"
+}
+
+ipv4_mcroute_starg()
+{
+	adf_install_starg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	do_test 4 10 10 "IPv4 mcroute (*,G)"
+}
+
+ipv6_mcroute_starg()
+{
+	adf_install_starg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	do_test 6 10 10 "IPv6 mcroute (*,G)"
+}
+
+ipv4_mcroute_starg_rx()
+{
+	adf_install_starg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	ipv4_do_test_rx 0 "IPv4 mcroute (*,G) ping"
+}
+
+ipv6_mcroute_starg_rx()
+{
+	adf_install_starg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	ipv6_do_test_rx 0 "IPv6 mcroute (*,G) ping"
+}
+
+ipv4_mcroute_noroute()
+{
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	do_test 4 0 0 "IPv4 mcroute, no route"
+}
+
+ipv6_mcroute_noroute()
+{
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	do_test 6 0 0 "IPv6 mcroute, no route"
+}
+
+ipv4_mcroute_fdb()
+{
+	adf_install_sg
+	vx10_create_wait local 192.0.2.100 dev "$IPMR" mcroute
+	bridge fdb add dev vx10 \
+		00:00:00:00:00:00 self static dst $GROUP4 via "$IPMR"
+	do_test 4 10 10 "IPv4 mcroute FDB"
+}
+
+ipv6_mcroute_fdb()
+{
+	adf_install_sg
+	vx20_create_wait local 2001:db8:4::1 dev "$IPMR" mcroute
+	bridge -6 fdb add dev vx20 \
+		00:00:00:00:00:00 self static dst $GROUP6 via "$IPMR"
+	do_test 6 10 10 "IPv6 mcroute FDB"
+}
+
+# Use FDB to configure VXLAN in a way where oif=0 for purposes of FIB lookup.
+ipv4_mcroute_fdb_oif0()
+{
+	adf_install_sg
+	vx10_create_wait local 192.0.2.100 group $GROUP4 dev "$IPMR" mcroute
+	bridge fdb del dev vx10 00:00:00:00:00:00
+	bridge fdb add dev vx10 00:00:00:00:00:00 self static dst $GROUP4
+	do_test 4 10 10 "IPv4 mcroute oif=0"
+}
+
+ipv6_mcroute_fdb_oif0()
+{
+	# The IPv6 tunnel lookup does not fall back to selection by source
+	# address. Instead it just does a FIB match, and that would find one of
+	# the several ff00::/8 multicast routes -- each device has one. In order
+	# to reliably force the $IPMR device, add a /128 route for the
+	# destination group address.
+	ip -6 route add table local multicast $GROUP6/128 dev "$IPMR"
+	defer ip -6 route del table local multicast $GROUP6/128 dev "$IPMR"
+
+	adf_install_sg
+	vx20_create_wait local 2001:db8:4::1 group $GROUP6 dev "$IPMR" mcroute
+	bridge -6 fdb del dev vx20 00:00:00:00:00:00
+	bridge -6 fdb add dev vx20 00:00:00:00:00:00 self static dst $GROUP6
+	do_test 6 10 10 "IPv6 mcroute oif=0"
+}
+
+# In oif=0 test as above, have FIB lookup resolve to loopback instead of IPMR.
+# This doesn't work with IPv6 -- a MC route on lo would be marked as RTF_REJECT.
+ipv4_mcroute_fdb_oif0_sep()
+{
+	adf_install_sg_sep
+
+	ip_addr_add lo 192.0.2.120/28
+	vx10_create_wait local 192.0.2.120 group $GROUP4 dev "$IPMR" mcroute
+	bridge fdb del dev vx10 00:00:00:00:00:00
+	bridge fdb add dev vx10 00:00:00:00:00:00 self static dst $GROUP4
+	do_test 4 10 10 "IPv4 mcroute TX!=RX oif=0"
+}
+
+ipv4_mcroute_fdb_oif0_sep_rx()
+{
+	adf_install_sg_sep_rx lo
+
+	ip_addr_add lo 192.0.2.120/28
+	vx10_create_wait local 192.0.2.120 group $GROUP4 dev "$IPMR" mcroute
+	bridge fdb del dev vx10 00:00:00:00:00:00
+	bridge fdb add dev vx10 00:00:00:00:00:00 self static dst $GROUP4
+	ipv4_do_test_rx 0 "IPv4 mcroute TX!=RX oif=0 ping"
+}
+
+ipv4_mcroute_fdb_sep_rx()
+{
+	adf_install_sg_sep_rx lo
+
+	ip_addr_add lo 192.0.2.120/28
+	vx10_create_wait local 192.0.2.120 group $GROUP4 dev "$IPMR" mcroute
+	bridge fdb del dev vx10 00:00:00:00:00:00
+	bridge fdb add dev vx10 00:00:00:00:00:00 self static dst $GROUP4 via lo
+	ipv4_do_test_rx 0 "IPv4 mcroute TX!=RX ping"
+}
+
+ipv6_mcroute_fdb_sep_rx()
+{
+	adf_install_sg_sep_rx "X$IPMR"
+
+	ip_addr_add "X$IPMR" 2001:db8:5::1/64
+	vx20_create_wait local 2001:db8:5::1 group $GROUP6 dev "$IPMR" mcroute
+	bridge -6 fdb del dev vx20 00:00:00:00:00:00
+	bridge -6 fdb add dev vx20 00:00:00:00:00:00 \
+			  self static dst $GROUP6 via "X$IPMR"
+	ipv6_do_test_rx 0 "IPv6 mcroute TX!=RX ping"
+}
+
+trap cleanup EXIT
+
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS
-- 
2.49.0

Re: [PATCH net-next 14/14] selftests: forwarding: Add a test for verifying VXLAN MC underlay

[Jakub Kicinski]

On Mon, 9 Jun 2025 22:50:30 +0200 Petr Machata wrote:
> Add tests for MC-routing underlay VXLAN traffic.

nit: we started using shellcheck, may be worth addressing the
warning-level complaints?

Re: [PATCH net-next 14/14] selftests: forwarding: Add a test for verifying VXLAN MC underlay

[Petr Machata]

Jakub Kicinski <kuba@kernel.org> writes:

> On Mon, 9 Jun 2025 22:50:30 +0200 Petr Machata wrote:
>> Add tests for MC-routing underlay VXLAN traffic.
>
> nit: we started using shellcheck, may be worth addressing the
> warning-level complaints?

Sure. Sorry, I noticed and meant to do that, but it slipped my mind :-|

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Jakub Kicinski]

On Mon, 9 Jun 2025 22:50:16 +0200 Petr Machata wrote:
> Multicast routing is today handled in the input path. Locally generated MC
> packets don't hit the IPMR code. Thus if a VXLAN remote address is
> multicast, the driver needs to set an OIF during route lookup. In practice
> that means that MC routing configuration needs to be kept in sync with the
> VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC
> routing code instead.

I think this leads to kmemleaks:

unreferenced object 0xffff88800aabe740 (size 232):
comm "kworker/0:2", pid 471, jiffies 4295215616
hex dump (first 32 bytes):
00 40 df 08 80 88 ff ff 00 f7 5d 98 ff ff ff ff  .@........].....
a1 55 19 95 ff ff ff ff 00 00 00 00 00 00 00 00  .U..............
backtrace (crc b1fabddb):
kmem_cache_alloc_noprof (./include/linux/kmemleak.h:43 mm/slub.c:4152 mm/slub.c:4197 mm/slub.c:4204) 
dst_alloc (net/core/dst.c:89) 
ip6_rt_pcpu_alloc (net/ipv6/route.c:342 net/ipv6/route.c:1419) 
ip6_pol_route (net/ipv6/route.c:1468 net/ipv6/route.c:2305) 
fib6_rule_lookup (./include/net/ip6_fib.h:617 net/ipv6/ip6_fib.c:326) 
ip6_route_output_flags (net/ipv6/route.c:2699) 
ip6_dst_lookup_tail.constprop.0 (net/ipv6/ip6_output.c:1128) 
ip6_dst_lookup_flow (net/ipv6/ip6_output.c:1260) 
udp_tunnel6_dst_lookup (net/ipv6/ip6_udp_tunnel.c:165 net/ipv6/ip6_udp_tunnel.c:135) ip6_udp_tunnel 
vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2540 (discriminator 4)) vxlan 
vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2809) vxlan 
dev_hard_start_xmit (./include/linux/netdevice.h:5215 ./include/linux/netdevice.h:5224 net/core/dev.c:3830 net/core/dev.c:3846) 
__dev_queue_xmit (net/core/dev.h:356 net/core/dev.c:4714) 
ip6_finish_output2 (./include/net/neighbour.h:539 net/ipv6/ip6_output.c:141) 
ip6_finish_output.constprop.0 (net/ipv6/ip6_output.c:215 net/ipv6/ip6_output.c:226) 
mld_sendpack (net/ipv6/mcast.c:1872) 

hit by netdevsim udp_tunnel_nic.sh

Also, do you have a branch with the iproute2 patches we could pull 
in the CI?

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Petr Machata]

Jakub Kicinski <kuba@kernel.org> writes:

> On Mon, 9 Jun 2025 22:50:16 +0200 Petr Machata wrote:
>> Multicast routing is today handled in the input path. Locally generated MC
>> packets don't hit the IPMR code. Thus if a VXLAN remote address is
>> multicast, the driver needs to set an OIF during route lookup. In practice
>> that means that MC routing configuration needs to be kept in sync with the
>> VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC
>> routing code instead.
>
> I think this leads to kmemleaks:
> [...]
> hit by netdevsim udp_tunnel_nic.sh

Thanks, I'll take a look.

> Also, do you have a branch with the iproute2 patches we could pull 
> in the CI?

My bad, didn't think of it:
https://github.com/pmachata/iproute2/commits/vxlan_mc_ul/

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Petr Machata]

Petr Machata <petrm@nvidia.com> writes:

> Jakub Kicinski <kuba@kernel.org> writes:
>
>> On Mon, 9 Jun 2025 22:50:16 +0200 Petr Machata wrote:
>>> Multicast routing is today handled in the input path. Locally generated MC
>>> packets don't hit the IPMR code. Thus if a VXLAN remote address is
>>> multicast, the driver needs to set an OIF during route lookup. In practice
>>> that means that MC routing configuration needs to be kept in sync with the
>>> VXLAN FDB and MDB. Ideally, the VXLAN packets would be routed by the MC
>>> routing code instead.
>>
>> I think this leads to kmemleaks:
>> [...]
>> hit by netdevsim udp_tunnel_nic.sh
>
> Thanks, I'll take a look.

Hmm, I can't reproduce this :-| I'm using the following incantation to
build the kernel:

    vng --build --config tools/testing/selftests/net/forwarding/config \
                --config tools/testing/selftests/drivers/net/config \
                --config tools/testing/selftests/drivers/net/netdevsim/config \
                --config kernel/configs/debug.config

And run the test like so:

    vng -v --run . --user root --cpus 4 -- \
        make -C tools/testing/selftests TARGETS=drivers/net/netdevsim \
                TEST_PROGS=udp_tunnel_nic.sh TEST_GEN_PROGS="" run_tests

vng -v --run . --user root --cpus 4 -- \
        bash -c 'make -C tools/testing/selftests TARGETS=drivers/net/netdevsim \
                        TEST_PROGS=udp_tunnel_nic.sh TEST_GEN_PROGS="" run_tests; \
                 echo scan > /sys/kernel/debug/kmemleak; \
                 cat /sys/kernel/debug/kmemleak'

Anything I'm missing, or is this what the CI is doing, more or less?

Could it actually have been caused by another test? The howto page
mentions that the CI is running the tests one at a time, so I don't
suppose that's a possibility.

I'll try to run a more fuller suite tomorrow and star at the code a bit
to see if I might be missing an error branch or something.

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Jakub Kicinski]

On Wed, 11 Jun 2025 17:30:15 +0200 Petr Machata wrote:
> Could it actually have been caused by another test? The howto page
> mentions that the CI is running the tests one at a time, so I don't
> suppose that's a possibility.
> 
> I'll try to run a more fuller suite tomorrow and star at the code a bit
> to see if I might be missing an error branch or something.

We also hit a crash in ipv6 fcnal.sh, too. Looks like this is either a
kmemleak false positive or possibly related to the rtnl changes in ipv6.
Either way I it's not related to you changes, sorry about that! :(

[ 2900.792890] BUG: kernel NULL pointer dereference, address: 0000000000000108
[ 2900.792961] #PF: supervisor read access in kernel mode
[ 2900.793017] #PF: error_code(0x0000) - not-present page
[ 2900.793053] PGD 8fd6067 P4D 8fd6067 PUD 6402067 PMD 0 
[ 2900.793097] Oops: Oops: 0000 [#1] SMP NOPTI
[ 2900.793127] CPU: 0 UID: 0 PID: 15652 Comm: nettest Not tainted 6.15.0-virtme #1 PREEMPT(voluntary) 
[ 2900.793200] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 2900.793245] RIP: 0010:ip6_pol_route+0x286/0x4a0
[ 2900.793290] Code: 0c 24 0f 85 fb 01 00 00 09 ca 0f 88 2f 01 00 00 e8 cf 11 43 ff 83 cb 08 48 8d 7c 24 18 e8 32 7b ff ff 0f b7 cb ba ff ff ff ff <4c> 8b 80 08 01 00 00 48 89 c6 49 89 c7 49 8d b8 80 06 00 00 4c 89
[ 2900.793422] RSP: 0018:ffffc08a0932f480 EFLAGS: 00010246
[ 2900.793460] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
[ 2900.793521] RDX: 00000000ffffffff RSI: ffffc08a0932f740 RDI: ffff9adac8c8f1a8
[ 2900.793580] RBP: ffff9adac87458c0 R08: 0000000000000000 R09: 0000000000000000
[ 2900.793635] R10: 0000000000000000 R11: 0000000000000040 R12: ffff9adac82e362c
[ 2900.793692] R13: ffff9adac82e3600 R14: 0000000000000080 R15: 0000000000000000
[ 2900.793752] FS:  00007f3418913740(0000) GS:ffff9adb7373a000(0000) knlGS:0000000000000000
[ 2900.793816] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2900.793864] CR2: 0000000000000108 CR3: 0000000008007004 CR4: 0000000000772ef0
[ 2900.793920] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 2900.793977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 2900.794031] PKRU: 55555554
[ 2900.794050] Call Trace:
[ 2900.794070]  <TASK>
[ 2900.794090]  ? __pfx_ip6_pol_route_output+0x10/0x10
[ 2900.794131]  fib6_rule_action+0xe3/0x310
[ 2900.794166]  fib_rules_lookup+0x1b2/0x2b0
[ 2900.794200]  ? __pfx_ip6_pol_route_output+0x10/0x10
[ 2900.794241]  fib6_rule_lookup+0xa9/0x270
[ 2900.794271]  ? __pfx_ip6_pol_route_output+0x10/0x10
[ 2900.794310]  ip6_route_output_flags+0xab/0x180
[ 2900.794353]  ip6_dst_lookup_tail.constprop.0+0x282/0x340
[ 2900.794394]  ip6_dst_lookup_flow+0x46/0xc0
[ 2900.794422]  vrf_xmit+0x100/0x4a0
[ 2900.794459]  dev_hard_start_xmit+0x8d/0x1c0

https://netdev-3.bots.linux.dev/vmksft-net/results/160541/vm-crash-thr0-0

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Kuniyuki Iwashima]

From: Jakub Kicinski <kuba@kernel.org>
Date: Wed, 11 Jun 2025 13:23:20 -0700
> On Wed, 11 Jun 2025 17:30:15 +0200 Petr Machata wrote:
> > Could it actually have been caused by another test? The howto page
> > mentions that the CI is running the tests one at a time, so I don't
> > suppose that's a possibility.
> > 
> > I'll try to run a more fuller suite tomorrow and star at the code a bit
> > to see if I might be missing an error branch or something.
> 
> We also hit a crash in ipv6 fcnal.sh, too. Looks like this is either a
> kmemleak false positive or possibly related to the rtnl changes in ipv6.
> Either way I it's not related to you changes, sorry about that! :(
> 
> [ 2900.792890] BUG: kernel NULL pointer dereference, address: 0000000000000108
> [ 2900.792961] #PF: supervisor read access in kernel mode
> [ 2900.793017] #PF: error_code(0x0000) - not-present page
> [ 2900.793053] PGD 8fd6067 P4D 8fd6067 PUD 6402067 PMD 0 
> [ 2900.793097] Oops: Oops: 0000 [#1] SMP NOPTI
> [ 2900.793127] CPU: 0 UID: 0 PID: 15652 Comm: nettest Not tainted 6.15.0-virtme #1 PREEMPT(voluntary) 
> [ 2900.793200] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> [ 2900.793245] RIP: 0010:ip6_pol_route+0x286/0x4a0

fwiw, my local syzkaller had the same splat on 6a325aed130b,
where my IPv6 series hadn't landed, and syzbot had a similar
one on f1b785f4c787, where my RTNL work was on the prep stage,
so I think this is an old? bug :)

I'll see if the .syz repro in the report still works on the latest.

syzbot:
https://lore.kernel.org/netdev/67a21f26.050a0220.163cdc.0068.GAE@google.com/

syzkaller:
---8<---
BUG: unable to handle page fault for address: 00007f93e4d51a23
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 12cd4c067 P4D 125130067 PUD 0 
Oops: Oops: 0000 [#1] SMP
CPU: 1 UID: 0 PID: 2259 Comm: syz.2.555 Not tainted 6.15.0-rc1-00220-g6a325aed130b #2 PREEMPT(voluntary)  fb2957dd255dfc2983199dfa2ccdedc09370f316
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:rt_genid_ipv6 include/net/net_namespace.h:537 [inline]
RIP: 0010:rt6_is_valid net/ipv6/route.c:1435 [inline]
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1445 [inline]
RIP: 0010:ip6_pol_route+0x301/0x9d0 net/ipv6/route.c:2298
Code: a9 fe 4d 85 ff 4c 8b 74 24 10 74 3b 41 8b 9f 98 00 00 00 31 ff 89 de e8 3d 37 a9 fe 85 db 74 33 49 8b 07 48 8b 80 08 01 00 00 <8b> a8 24 0a 00 00 89 df 89 ee e8 f0 34 a9 fe 39 eb 75 20 e8 67 33
RSP: 0018:ffa0000000c3ba20 EFLAGS: 00010202
RAX: 00007f93e4d50fff RBX: 000000001ac62540 RCX: 0000000000000002
RDX: ff11000005e99700 RSI: 000000001ac62540 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffff0000 R11: 0000000000000002 R12: ffffffff829af127
R13: 0000000000000000 R14: ff110001053e2580 R15: ff1100012505f400
FS:  00007f190e8276c0(0000) GS:ff110001b79d2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93e4d51a23 CR3: 000000011d7b5004 CR4: 0000000000771ef0
DR0: 0000000080000001 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000600
PKRU: 80000000
Call Trace:
 <TASK>
 pol_lookup_func include/net/ip6_fib.h:616 [inline]
 fib6_rule_lookup+0xe8/0x2a0 net/ipv6/fib6_rules.c:120
 ip6_route_output_flags_noref net/ipv6/route.c:2673 [inline]
 ip6_route_output_flags+0x188/0x260 net/ipv6/route.c:2685
 ip6_route_output include/net/ip6_route.h:93 [inline]
 ip6_dst_lookup_tail+0x9a/0x7d0 net/ipv6/ip6_output.c:1128
 ip6_dst_lookup_flow+0x47/0xe0 net/ipv6/ip6_output.c:1259
 tcp_v6_connect+0x50c/0x8e0 net/ipv6/tcp_ipv6.c:277
 mptcp_connect+0x389/0x680 net/mptcp/protocol.c:3683
 __inet_stream_connect+0x11f/0x5c0 net/ipv4/af_inet.c:677
 inet_stream_connect+0x36/0x50 net/ipv4/af_inet.c:748
 __sys_connect_file net/socket.c:2038 [inline]
 __sys_connect+0x17b/0x220 net/socket.c:2057
 __do_sys_connect net/socket.c:2063 [inline]
 __se_sys_connect net/socket.c:2060 [inline]
 __x64_sys_connect+0x1c/0x20 net/socket.c:2060
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc8/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f19101bd169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f190e827038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f19103d5fa0 RCX: 00007f19101bd169
RDX: 000000000000001c RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f191023e730 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f19103d5fa0 R15: 00007f19104ffa28
 </TASK>
Modules linked in:
CR2: 00007f93e4d51a23
---[ end trace 0000000000000000 ]---
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:rt_genid_ipv6 include/net/net_namespace.h:537 [inline]
RIP: 0010:rt6_is_valid net/ipv6/route.c:1435 [inline]
RIP: 0010:rt6_get_pcpu_route net/ipv6/route.c:1445 [inline]
RIP: 0010:ip6_pol_route+0x301/0x9d0 net/ipv6/route.c:2298
Code: a9 fe 4d 85 ff 4c 8b 74 24 10 74 3b 41 8b 9f 98 00 00 00 31 ff 89 de e8 3d 37 a9 fe 85 db 74 33 49 8b 07 48 8b 80 08 01 00 00 <8b> a8 24 0a 00 00 89 df 89 ee e8 f0 34 a9 fe 39 eb 75 20 e8 67 33
RSP: 0018:ffa0000000c3ba20 EFLAGS: 00010202
RAX: 00007f93e4d50fff RBX: 000000001ac62540 RCX: 0000000000000002
RDX: ff11000005e99700 RSI: 000000001ac62540 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffff0000 R11: 0000000000000002 R12: ffffffff829af127
R13: 0000000000000000 R14: ff110001053e2580 R15: ff1100012505f400
FS:  00007f190e8276c0(0000) GS:ff110001b79d2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f93e4d51a23 CR3: 000000011d7b5004 CR4: 0000000000771ef0
DR0: 0000000080000001 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000600
PKRU: 80000000
----------------
Code disassembly (best guess):
   0:	a9 fe 4d 85 ff       	test   $0xff854dfe,%eax
   5:	4c 8b 74 24 10       	mov    0x10(%rsp),%r14
   a:	74 3b                	je     0x47
   c:	41 8b 9f 98 00 00 00 	mov    0x98(%r15),%ebx
  13:	31 ff                	xor    %edi,%edi
  15:	89 de                	mov    %ebx,%esi
  17:	e8 3d 37 a9 fe       	call   0xfea93759
  1c:	85 db                	test   %ebx,%ebx
  1e:	74 33                	je     0x53
  20:	49 8b 07             	mov    (%r15),%rax
  23:	48 8b 80 08 01 00 00 	mov    0x108(%rax),%rax
* 2a:	8b a8 24 0a 00 00    	mov    0xa24(%rax),%ebp <-- trapping instruction
  30:	89 df                	mov    %ebx,%edi
  32:	89 ee                	mov    %ebp,%esi
  34:	e8 f0 34 a9 fe       	call   0xfea93529
  39:	39 eb                	cmp    %ebp,%ebx
  3b:	75 20                	jne    0x5d
  3d:	e8                   	.byte 0xe8
  3e:	67                   	addr32
  3f:	33                   	.byte 0x33
---8<---

Re: [PATCH net-next 00/14] ipmr, ip6mr: Allow MC-routing locally-generated MC packets

[Petr Machata]

Jakub Kicinski <kuba@kernel.org> writes:

> On Wed, 11 Jun 2025 17:30:15 +0200 Petr Machata wrote:
>> Could it actually have been caused by another test? The howto page
>> mentions that the CI is running the tests one at a time, so I don't
>> suppose that's a possibility.
>> 
>> I'll try to run a more fuller suite tomorrow and star at the code a bit
>> to see if I might be missing an error branch or something.
>
> We also hit a crash in ipv6 fcnal.sh, too. Looks like this is either a
> kmemleak false positive or possibly related to the rtnl changes in ipv6.
> Either way I it's not related to you changes, sorry about that! :(

No problem.

> [ 2900.792890] BUG: kernel NULL pointer dereference, address: 0000000000000108
> [ 2900.792961] #PF: supervisor read access in kernel mode
> [ 2900.793017] #PF: error_code(0x0000) - not-present page
> [ 2900.793053] PGD 8fd6067 P4D 8fd6067 PUD 6402067 PMD 0 
> [ 2900.793097] Oops: Oops: 0000 [#1] SMP NOPTI
> [ 2900.793127] CPU: 0 UID: 0 PID: 15652 Comm: nettest Not tainted 6.15.0-virtme #1 PREEMPT(voluntary) 
> [ 2900.793200] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> [ 2900.793245] RIP: 0010:ip6_pol_route+0x286/0x4a0
> [ 2900.793290] Code: 0c 24 0f 85 fb 01 00 00 09 ca 0f 88 2f 01 00 00 e8 cf 11 43 ff 83 cb 08 48 8d 7c 24 18 e8 32 7b ff ff 0f b7 cb ba ff ff ff ff <4c> 8b 80 08 01 00 00 48 89 c6 49 89 c7 49 8d b8 80 06 00 00 4c 89
> [ 2900.793422] RSP: 0018:ffffc08a0932f480 EFLAGS: 00010246
> [ 2900.793460] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008
> [ 2900.793521] RDX: 00000000ffffffff RSI: ffffc08a0932f740 RDI: ffff9adac8c8f1a8
> [ 2900.793580] RBP: ffff9adac87458c0 R08: 0000000000000000 R09: 0000000000000000
> [ 2900.793635] R10: 0000000000000000 R11: 0000000000000040 R12: ffff9adac82e362c
> [ 2900.793692] R13: ffff9adac82e3600 R14: 0000000000000080 R15: 0000000000000000
> [ 2900.793752] FS:  00007f3418913740(0000) GS:ffff9adb7373a000(0000) knlGS:0000000000000000
> [ 2900.793816] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 2900.793864] CR2: 0000000000000108 CR3: 0000000008007004 CR4: 0000000000772ef0
> [ 2900.793920] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 2900.793977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 2900.794031] PKRU: 55555554
> [ 2900.794050] Call Trace:
> [ 2900.794070]  <TASK>
> [ 2900.794090]  ? __pfx_ip6_pol_route_output+0x10/0x10
> [ 2900.794131]  fib6_rule_action+0xe3/0x310
> [ 2900.794166]  fib_rules_lookup+0x1b2/0x2b0
> [ 2900.794200]  ? __pfx_ip6_pol_route_output+0x10/0x10
> [ 2900.794241]  fib6_rule_lookup+0xa9/0x270
> [ 2900.794271]  ? __pfx_ip6_pol_route_output+0x10/0x10
> [ 2900.794310]  ip6_route_output_flags+0xab/0x180
> [ 2900.794353]  ip6_dst_lookup_tail.constprop.0+0x282/0x340
> [ 2900.794394]  ip6_dst_lookup_flow+0x46/0xc0
> [ 2900.794422]  vrf_xmit+0x100/0x4a0
> [ 2900.794459]  dev_hard_start_xmit+0x8d/0x1c0
>
> https://netdev-3.bots.linux.dev/vmksft-net/results/160541/vm-crash-thr0-0

Didn't see this issue either FWIW.