[PATCH v6 0/4] Add VRF support for VXLAN underlay

[PATCH v6 0/4] Add VRF support for VXLAN underlay

[Alexis Bauvin]

v5 -> v6:
- remove automatic rebinding patch following Roopa Prabhu's advice

v4 -> v5:
- move test script to its own patch (6/6)
- add schematic for test script
- apply David Ahern comments to the test script

v3 -> v4:
- rename vxlan_is_in_l3mdev_chain to netdev_is_upper master
- move it to net/core/dev.c
- make it return bool instead of int
- check if remote_ifindex is zero before resolving the l3mdev
- add testing script

v2 -> v3:
- fix build when CONFIG_NET_IPV6 is off
- fix build "unused l3mdev_master_upper_ifindex_by_index" build error with some
  configs

v1 -> v2:
- move vxlan_get_l3mdev from vxlan driver to l3mdev driver as
  l3mdev_master_upper_ifindex_by_index
- vxlan: rename variables named l3mdev_ifindex to ifindex

v0 -> v1:
- fix typos

We are trying to isolate the VXLAN traffic from different VMs with VRF as shown
in the schemas below:

+-------------------------+   +----------------------------+
| +----------+            |   |     +------------+         |
| |          |            |   |     |            |         |
| | tap-red  |            |   |     |  tap-blue  |         |
| |          |            |   |     |            |         |
| +----+-----+            |   |     +-----+------+         |
|      |                  |   |           |                |
|      |                  |   |           |                |
| +----+---+              |   |      +----+----+           |
| |        |              |   |      |         |           |
| | br-red |              |   |      | br-blue |           |
| |        |              |   |      |         |           |
| +----+---+              |   |      +----+----+           |
|      |                  |   |           |                |
|      |                  |   |           |                |
|      |                  |   |           |                |
| +----+--------+         |   |     +--------------+       |
| |             |         |   |     |              |       |
| |  vxlan-red  |         |   |     |  vxlan-blue  |       |
| |             |         |   |     |              |       |
| +------+------+         |   |     +-------+------+       |
|        |                |   |             |              |
|        |           VRF  |   |             |          VRF |
|        |           red  |   |             |         blue |
+-------------------------+   +----------------------------+
         |                                  |
         |                                  |
 +---------------------------------------------------------+
 |       |                                  |              |
 |       |                                  |              |
 |       |         +--------------+         |              |
 |       |         |              |         |              |
 |       +---------+  eth0.2030   +---------+              |
 |                 |  10.0.0.1/24 |                        |
 |                 +-----+--------+                    VRF |
 |                       |                            green|
 +---------------------------------------------------------+
                         |
                         |
                    +----+---+
                    |        |
                    |  eth0  |
                    |        |
                    +--------+


iproute2 commands to reproduce the setup:

ip link add green type vrf table 1
ip link set green up
ip link add eth0.2030 link eth0 type vlan id 2030
ip link set eth0.2030 master green
ip addr add 10.0.0.1/24 dev eth0.2030
ip link set eth0.2030 up

ip link add blue type vrf table 2
ip link set blue up
ip link add br-blue type bridge
ip link set br-blue master blue
ip link set br-blue up
ip link add vxlan-blue type vxlan id 2 local 10.0.0.1 dev eth0.2030 \
 port 4789
ip link set vxlan-blue master br-blue
ip link set vxlan-blue up
ip link set tap-blue master br-blue
ip link set tap-blue up

ip link add red type vrf table 3
ip link set red up
ip link add br-red type bridge
ip link set br-red master red
ip link set br-red up
ip link add vxlan-red type vxlan id 3 local 10.0.0.1 dev eth0.2030 \
 port 4789
ip link set vxlan-red master br-red
ip link set vxlan-red up
ip link set tap-red master br-red
ip link set tap-red up

We faced some issue in the datapath, here are the details:

* Egress traffic:
The vxlan packets are sent directly to the default VRF because it's where the
socket is bound, therefore the traffic has a default route via eth0. the
workarount is to force this traffic to VRF green with ip rules.

* Ingress traffic:
When receiving the traffic on eth0.2030 the vxlan socket is unreachable from
VRF green. The workaround is to enable *udp_l3mdev_accept* sysctl, but
this breaks isolation between overlay and underlay: packets sent from
blue or red by e.g. a guest VM will be accepted by the socket, allowing
injection of VXLAN packets from the overlay.

This patch serie fixes the issues describe above by allowing VXLAN socket to be
bound to a specific VRF device therefore looking up in the correct table.

Alexis Bauvin (4):
  udp_tunnel: add config option to bind to a device
  l3mdev: add function to retreive upper master
  vxlan: add support for underlay in non-default VRF
  test/net: Add script for VXLAN underlay in a VRF

 drivers/net/vxlan.c                           |  32 +++--
 include/net/l3mdev.h                          |  22 +++
 include/net/udp_tunnel.h                      |   1 +
 net/ipv4/udp_tunnel.c                         |  10 ++
 net/ipv6/ip6_udp_tunnel.c                     |   9 ++
 net/l3mdev/l3mdev.c                           |  18 +++
 tools/testing/selftests/net/Makefile          |   1 +
 .../selftests/net/test_vxlan_under_vrf.sh     | 129 ++++++++++++++++++
 8 files changed, 214 insertions(+), 8 deletions(-)
 create mode 100755 tools/testing/selftests/net/test_vxlan_under_vrf.sh

-- 

[PATCH v6 1/4] udp_tunnel: add config option to bind to a device

[Alexis Bauvin]

UDP tunnel sockets are always opened unbound to a specific device. This
patch allow the socket to be bound on a custom device, which
incidentally makes UDP tunnels VRF-aware if binding to an l3mdev.

Signed-off-by: Alexis Bauvin <abauvin@scaleway.com>
Reviewed-by: Amine Kherbouche <akherbouche@scaleway.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: Amine Kherbouche <akherbouche@scaleway.com>
---
 include/net/udp_tunnel.h  |  1 +
 net/ipv4/udp_tunnel.c     | 10 ++++++++++
 net/ipv6/ip6_udp_tunnel.c |  9 +++++++++
 3 files changed, 20 insertions(+)

diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index fe680ab6b15a..9f7970d010f9 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -30,6 +30,7 @@ struct udp_port_cfg {
 
 	__be16			local_udp_port;
 	__be16			peer_udp_port;
+	int			bind_ifindex;
 	unsigned int		use_udp_checksums:1,
 				use_udp6_tx_checksums:1,
 				use_udp6_rx_checksums:1,
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 6539ff15e9a3..dc68e15a4f72 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -20,6 +20,16 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
 	if (err < 0)
 		goto error;
 
+	if (cfg->bind_ifindex) {
+		struct net_device *dev;
+
+		dev = __dev_get_by_index(net, cfg->bind_ifindex);
+		err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
+					dev->name, strlen(dev->name) + 1);
+		if (err < 0)
+			goto error;
+	}
+
 	udp_addr.sin_family = AF_INET;
 	udp_addr.sin_addr = cfg->local_ip;
 	udp_addr.sin_port = cfg->local_udp_port;
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index b283f293ee4a..fc3811ef8787 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -31,6 +31,15 @@ int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 		if (err < 0)
 			goto error;
 	}
+	if (cfg->bind_ifindex) {
+		struct net_device *dev;
+
+		dev = __dev_get_by_index(net, cfg->bind_ifindex);
+		err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
+					dev->name, strlen(dev->name) + 1);
+		if (err < 0)
+			goto error;
+	}
 
 	udp6_addr.sin6_family = AF_INET6;
 	memcpy(&udp6_addr.sin6_addr, &cfg->local_ip6,
-- 

[PATCH v6 2/4] l3mdev: add function to retreive upper master

[Alexis Bauvin]

Existing functions to retreive the l3mdev of a device did not walk the
master chain to find the upper master. This patch adds a function to
find the l3mdev, even indirect through e.g. a bridge:

+----------+
|          |
| vrf-blue |
|          |
+----+-----+
     |
     |
+----+-----+
|          |
| br-blue  |
|          |
+----+-----+
     |
     |
+----+-----+
|          |
|   eth0   |
|          |
+----------+

This will properly resolve the l3mdev of eth0 to vrf-blue.

Signed-off-by: Alexis Bauvin <abauvin@scaleway.com>
Reviewed-by: Amine Kherbouche <akherbouche@scaleway.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: Amine Kherbouche <akherbouche@scaleway.com>
---
 include/net/l3mdev.h | 22 ++++++++++++++++++++++
 net/l3mdev/l3mdev.c  | 18 ++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/net/l3mdev.h b/include/net/l3mdev.h
index 3832099289c5..78fa0ac4613c 100644
--- a/include/net/l3mdev.h
+++ b/include/net/l3mdev.h
@@ -101,6 +101,17 @@ struct net_device *l3mdev_master_dev_rcu(const struct net_device *_dev)
 	return master;
 }
 
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex);
+static inline
+int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
+{
+	rcu_read_lock();
+	ifindex = l3mdev_master_upper_ifindex_by_index_rcu(net, ifindex);
+	rcu_read_unlock();
+
+	return ifindex;
+}
+
 u32 l3mdev_fib_table_rcu(const struct net_device *dev);
 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex);
 static inline u32 l3mdev_fib_table(const struct net_device *dev)
@@ -207,6 +218,17 @@ static inline int l3mdev_master_ifindex_by_index(struct net *net, int ifindex)
 	return 0;
 }
 
+static inline
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
+{
+	return 0;
+}
+static inline
+int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
+{
+	return 0;
+}
+
 static inline
 struct net_device *l3mdev_master_dev_rcu(const struct net_device *dev)
 {
diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c
index 8da86ceca33d..309dee76724e 100644
--- a/net/l3mdev/l3mdev.c
+++ b/net/l3mdev/l3mdev.c
@@ -46,6 +46,24 @@ int l3mdev_master_ifindex_rcu(const struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
 
+/**
+ *	l3mdev_master_upper_ifindex_by_index - get index of upper l3 master
+ *					       device
+ *	@net: network namespace for device index lookup
+ *	@ifindex: targeted interface
+ */
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
+{
+	struct net_device *dev;
+
+	dev = dev_get_by_index_rcu(net, ifindex);
+	while (dev && !netif_is_l3_master(dev))
+		dev = netdev_master_upper_dev_get(dev);
+
+	return dev ? dev->ifindex : 0;
+}
+EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
+
 /**
  *	l3mdev_fib_table - get FIB table id associated with an L3
  *                             master interface
-- 

[PATCH v6 3/4] vxlan: add support for underlay in non-default VRF

[Alexis Bauvin]

Creating a VXLAN device with is underlay in the non-default VRF makes
egress route lookup fail or incorrect since it will resolve in the
default VRF, and ingress fail because the socket listens in the default
VRF.

This patch binds the underlying UDP tunnel socket to the l3mdev of the
lower device of the VXLAN device. This will listen in the proper VRF and
output traffic from said l3mdev, matching l3mdev routing rules and
looking up the correct routing table.

When the VXLAN device does not have a lower device, or the lower device
is in the default VRF, the socket will not be bound to any interface,
keeping the previous behaviour.

The underlay l3mdev is deduced from the VXLAN lower device
(IFLA_VXLAN_LINK).

+----------+                         +---------+
|          |                         |         |
| vrf-blue |                         | vrf-red |
|          |                         |         |
+----+-----+                         +----+----+
     |                                    |
     |                                    |
+----+-----+                         +----+----+
|          |                         |         |
| br-blue  |                         | br-red  |
|          |                         |         |
+----+-----+                         +---+-+---+
     |                                   | |
     |                             +-----+ +-----+
     |                             |             |
+----+-----+                +------+----+   +----+----+
|          |  lower device  |           |   |         |
|   eth0   | <- - - - - - - | vxlan-red |   | tap-red | (... more taps)
|          |                |           |   |         |
+----------+                +-----------+   +---------+

Signed-off-by: Alexis Bauvin <abauvin@scaleway.com>
Reviewed-by: Amine Kherbouche <akherbouche@scaleway.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: Amine Kherbouche <akherbouche@scaleway.com>
---
 drivers/net/vxlan.c | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 27bd586b94b0..8ba0a57ff958 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -212,7 +212,7 @@ static inline struct vxlan_rdst *first_remote_rtnl(struct vxlan_fdb *fdb)
  * and enabled unshareable flags.
  */
 static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
-					  __be16 port, u32 flags)
+					  __be16 port, u32 flags, int ifindex)
 {
 	struct vxlan_sock *vs;
 
@@ -221,7 +221,8 @@ static struct vxlan_sock *vxlan_find_sock(struct net *net, sa_family_t family,
 	hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
 		if (inet_sk(vs->sock->sk)->inet_sport == port &&
 		    vxlan_get_sk_family(vs) == family &&
-		    vs->flags == flags)
+		    vs->flags == flags &&
+		    vs->sock->sk->sk_bound_dev_if == ifindex)
 			return vs;
 	}
 	return NULL;
@@ -261,7 +262,7 @@ static struct vxlan_dev *vxlan_find_vni(struct net *net, int ifindex,
 {
 	struct vxlan_sock *vs;
 
-	vs = vxlan_find_sock(net, family, port, flags);
+	vs = vxlan_find_sock(net, family, port, flags, ifindex);
 	if (!vs)
 		return NULL;
 
@@ -2172,6 +2173,9 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 		struct rtable *rt;
 		__be16 df = 0;
 
+		if (!ifindex)
+			ifindex = sock4->sock->sk->sk_bound_dev_if;
+
 		rt = vxlan_get_route(vxlan, dev, sock4, skb, ifindex, tos,
 				     dst->sin.sin_addr.s_addr,
 				     &local_ip.sin.sin_addr.s_addr,
@@ -2210,6 +2214,9 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	} else {
 		struct vxlan_sock *sock6 = rcu_dereference(vxlan->vn6_sock);
 
+		if (!ifindex)
+			ifindex = sock6->sock->sk->sk_bound_dev_if;
+
 		ndst = vxlan6_get_route(vxlan, dev, sock6, skb, ifindex, tos,
 					label, &dst->sin6.sin6_addr,
 					&local_ip.sin6.sin6_addr,
@@ -2813,7 +2820,7 @@ static const struct ethtool_ops vxlan_ethtool_ops = {
 };
 
 static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
-					__be16 port, u32 flags)
+					__be16 port, u32 flags, int ifindex)
 {
 	struct socket *sock;
 	struct udp_port_cfg udp_conf;
@@ -2831,6 +2838,7 @@ static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
 	}
 
 	udp_conf.local_udp_port = port;
+	udp_conf.bind_ifindex = ifindex;
 
 	/* Open UDP socket */
 	err = udp_sock_create(net, &udp_conf, &sock);
@@ -2842,7 +2850,8 @@ static struct socket *vxlan_create_sock(struct net *net, bool ipv6,
 
 /* Create new listen socket if needed */
 static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
-					      __be16 port, u32 flags)
+					      __be16 port, u32 flags,
+					      int ifindex)
 {
 	struct vxlan_net *vn = net_generic(net, vxlan_net_id);
 	struct vxlan_sock *vs;
@@ -2857,7 +2866,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
 	for (h = 0; h < VNI_HASH_SIZE; ++h)
 		INIT_HLIST_HEAD(&vs->vni_list[h]);
 
-	sock = vxlan_create_sock(net, ipv6, port, flags);
+	sock = vxlan_create_sock(net, ipv6, port, flags, ifindex);
 	if (IS_ERR(sock)) {
 		kfree(vs);
 		return ERR_CAST(sock);
@@ -2894,11 +2903,17 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
 	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
 	struct vxlan_sock *vs = NULL;
 	struct vxlan_dev_node *node;
+	int l3mdev_index = 0;
+
+	if (vxlan->cfg.remote_ifindex)
+		l3mdev_index = l3mdev_master_upper_ifindex_by_index(
+			vxlan->net, vxlan->cfg.remote_ifindex);
 
 	if (!vxlan->cfg.no_share) {
 		spin_lock(&vn->sock_lock);
 		vs = vxlan_find_sock(vxlan->net, ipv6 ? AF_INET6 : AF_INET,
-				     vxlan->cfg.dst_port, vxlan->cfg.flags);
+				     vxlan->cfg.dst_port, vxlan->cfg.flags,
+				     l3mdev_index);
 		if (vs && !refcount_inc_not_zero(&vs->refcnt)) {
 			spin_unlock(&vn->sock_lock);
 			return -EBUSY;
@@ -2907,7 +2922,8 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
 	}
 	if (!vs)
 		vs = vxlan_socket_create(vxlan->net, ipv6,
-					 vxlan->cfg.dst_port, vxlan->cfg.flags);
+					 vxlan->cfg.dst_port, vxlan->cfg.flags,
+					 l3mdev_index);
 	if (IS_ERR(vs))
 		return PTR_ERR(vs);
 #if IS_ENABLED(CONFIG_IPV6)
-- 

[PATCH v6 4/4] test/net: Add script for VXLAN underlay in a VRF

[Alexis Bauvin]

This script tests the support of a VXLAN underlay in a non-default VRF.

It does so by simulating two hypervisors and two VMs, an extended L2
between the VMs with the hypervisors as VTEPs with the underlay in a
VRF, and finally by pinging the two VMs.

It also tests that moving the underlay from a VRF to another works when
down/up the VXLAN interface.

Signed-off-by: Alexis Bauvin <abauvin@scaleway.com>
Reviewed-by: Amine Kherbouche <akherbouche@scaleway.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: Amine Kherbouche <akherbouche@scaleway.com>
---
 tools/testing/selftests/net/Makefile          |   1 +
 .../selftests/net/test_vxlan_under_vrf.sh     | 129 ++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100755 tools/testing/selftests/net/test_vxlan_under_vrf.sh

diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 919aa2ac00af..d45295ca56ce 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -7,6 +7,7 @@ CFLAGS += -I../../../../usr/include/
 TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh rtnetlink.sh
 TEST_PROGS += fib_tests.sh fib-onlink-tests.sh pmtu.sh udpgso.sh
 TEST_PROGS += udpgso_bench.sh fib_rule_tests.sh msg_zerocopy.sh psock_snd.sh
+TEST_PROGS += test_vxlan_under_vrf.sh
 TEST_PROGS_EXTENDED := in_netns.sh
 TEST_GEN_FILES =  socket
 TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy
diff --git a/tools/testing/selftests/net/test_vxlan_under_vrf.sh b/tools/testing/selftests/net/test_vxlan_under_vrf.sh
new file mode 100755
index 000000000000..09f9ed92cbe4
--- /dev/null
+++ b/tools/testing/selftests/net/test_vxlan_under_vrf.sh
@@ -0,0 +1,129 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+# This test is for checking VXLAN underlay in a non-default VRF.
+#
+# It simulates two hypervisors running a VM each using four network namespaces:
+# two for the HVs, two for the VMs.
+# A small VXLAN tunnel is made between the two hypervisors to have the two vms
+# in the same virtual L2:
+#
+# +-------------------+                                    +-------------------+
+# |                   |                                    |                   |
+# |    vm-1 netns     |                                    |    vm-2 netns     |
+# |                   |                                    |                   |
+# |  +-------------+  |                                    |  +-------------+  |
+# |  |   veth-hv   |  |                                    |  |   veth-hv   |  |
+# |  | 10.0.0.1/24 |  |                                    |  | 10.0.0.2/24 |  |
+# |  +-------------+  |                                    |  +-------------+  |
+# |        .          |                                    |         .         |
+# +-------------------+                                    +-------------------+
+#          .                                                         .
+#          .                                                         .
+#          .                                                         .
+# +-----------------------------------+   +------------------------------------+
+# |        .                          |   |                          .         |
+# |  +----------+                     |   |                     +----------+   |
+# |  | veth-tap |                     |   |                     | veth-tap |   |
+# |  +----+-----+                     |   |                     +----+-----+   |
+# |       |                           |   |                          |         |
+# |    +--+--+      +--------------+  |   |  +--------------+     +--+--+      |
+# |    | br0 |      | vrf-underlay |  |   |  | vrf-underlay |     | br0 |      |
+# |    +--+--+      +-------+------+  |   |  +------+-------+     +--+--+      |
+# |       |                 |         |   |         |                |         |
+# |   +---+----+    +-------+-------+ |   | +-------+-------+    +---+----+    |
+# |   | vxlan0 |....|     veth0     |.|...|.|     veth0     |....| vxlan0 |    |
+# |   +--------+    | 172.16.0.1/24 | |   | | 172.16.0.2/24 |    +--------+    |
+# |                 +---------------+ |   | +---------------+                  |
+# |                                   |   |                                    |
+# |             hv-1 netns            |   |           hv-2 netns               |
+# |                                   |   |                                    |
+# +-----------------------------------+   +------------------------------------+
+#
+# This tests both the connectivity between vm-1 and vm-2, and that the underlay
+# can be moved in and out of the vrf by unsetting and setting veth0's master.
+
+set -e
+
+cleanup() {
+    ip link del veth-hv-1 2>/dev/null || true
+    ip link del veth-tap 2>/dev/null || true
+
+    for ns in hv-1 hv-2 vm-1 vm-2; do
+        ip netns del $ns || true
+    done
+}
+
+# Clean start
+cleanup &> /dev/null
+
+[[ $1 == "clean" ]] && exit 0
+
+trap cleanup EXIT
+
+# Setup "Hypervisors" simulated with netns
+ip link add veth-hv-1 type veth peer name veth-hv-2
+setup-hv-networking() {
+    hv=$1
+
+    ip netns add hv-$hv
+    ip link set veth-hv-$hv netns hv-$hv
+    ip -netns hv-$hv link set veth-hv-$hv name veth0
+
+    ip -netns hv-$hv link add vrf-underlay type vrf table 1
+    ip -netns hv-$hv link set vrf-underlay up
+    ip -netns hv-$hv addr add 172.16.0.$hv/24 dev veth0
+    ip -netns hv-$hv link set veth0 up
+
+    ip -netns hv-$hv link add br0 type bridge
+    ip -netns hv-$hv link set br0 up
+
+    ip -netns hv-$hv link add vxlan0 type vxlan id 10 local 172.16.0.$hv dev veth0 dstport 4789
+    ip -netns hv-$hv link set vxlan0 master br0
+    ip -netns hv-$hv link set vxlan0 up
+}
+setup-hv-networking 1
+setup-hv-networking 2
+
+# Check connectivity between HVs by pinging hv-2 from hv-1
+echo -n "Checking HV connectivity                                           "
+ip netns exec hv-1 ping -c 1 -W 1 172.16.0.2 &> /dev/null || (echo "[FAIL]"; false)
+echo "[ OK ]"
+
+# Setups a "VM" simulated by a netns an a veth pair
+setup-vm() {
+    id=$1
+
+    ip netns add vm-$id
+    ip link add veth-tap type veth peer name veth-hv
+
+    ip link set veth-tap netns hv-$id
+    ip -netns hv-$id link set veth-tap master br0
+    ip -netns hv-$id link set veth-tap up
+
+    ip link set veth-hv netns vm-$id
+    ip -netns vm-$id addr add 10.0.0.$id/24 dev veth-hv
+    ip -netns vm-$id link set veth-hv up
+}
+setup-vm 1
+setup-vm 2
+
+# Setup VTEP routes to make ARP work
+bridge -netns hv-1 fdb add 00:00:00:00:00:00 dev vxlan0 dst 172.16.0.2 self permanent
+bridge -netns hv-2 fdb add 00:00:00:00:00:00 dev vxlan0 dst 172.16.0.1 self permanent
+
+echo -n "Check VM connectivity through VXLAN (underlay in the default VRF)  "
+ip netns exec vm-1 ping -c 1 -W 1 10.0.0.2 &> /dev/null || (echo "[FAIL]"; false)
+echo "[ OK ]"
+
+# Move the underlay to a non-default VRF
+ip -netns hv-1 link set veth0 vrf vrf-underlay
+ip -netns hv-1 link set veth0 down
+ip -netns hv-1 link set veth0 up
+ip -netns hv-2 link set veth0 vrf vrf-underlay
+ip -netns hv-2 link set veth0 down
+ip -netns hv-2 link set veth0 up
+
+echo -n "Check VM connectivity through VXLAN (underlay in a VRF)            "
+ip netns exec vm-1 ping -c 1 -W 1 10.0.0.2 &> /dev/null || (echo "[FAIL]"; false)
+echo "[ OK ]"
-- 

Re: [PATCH v6 1/4] udp_tunnel: add config option to bind to a device

[Sabrina Dubroca]

2018-11-27, 14:05:42 +0100, Alexis Bauvin wrote:
> diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
> index 6539ff15e9a3..dc68e15a4f72 100644
> --- a/net/ipv4/udp_tunnel.c
> +++ b/net/ipv4/udp_tunnel.c
> @@ -20,6 +20,16 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
>  	if (err < 0)
>  		goto error;
>  
> +	if (cfg->bind_ifindex) {
> +		struct net_device *dev;
> +
> +		dev = __dev_get_by_index(net, cfg->bind_ifindex);

Quoting from net/core/dev.c:

 *	[...]                                    The device has not
 *	had its reference counter increased so the caller must be careful
 *	about locking. The caller must hold either the RTNL semaphore
 *	or @dev_base_lock.
 */

which is the case for VXLAN (and GENEVE) during ndo_open, but I don't
think other UDP tunnels (FOU, L2TP) are holding RTNL when they call
udp_sock_create(). dev_get_by_index() + dev_put() should be safe.

Also, I don't think it's a problem with vxlan, but this could handle
the case where __dev_get_by_index returns NULL.

> +		err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
> +					dev->name, strlen(dev->name) + 1);
> +		if (err < 0)
> +			goto error;
> +	}
> +
>  	udp_addr.sin_family = AF_INET;
>  	udp_addr.sin_addr = cfg->local_ip;
>  	udp_addr.sin_port = cfg->local_udp_port;

-- 
Sabrina

Re: [PATCH v6 1/4] udp_tunnel: add config option to bind to a device

[David Miller]

From: Alexis Bauvin <abauvin@scaleway.com>
Date: Tue, 27 Nov 2018 14:05:42 +0100

> UDP tunnel sockets are always opened unbound to a specific device. This
> patch allow the socket to be bound on a custom device, which
> incidentally makes UDP tunnels VRF-aware if binding to an l3mdev.
> 
> Signed-off-by: Alexis Bauvin <abauvin@scaleway.com>
> Reviewed-by: Amine Kherbouche <akherbouche@scaleway.com>
> Reviewed-by: David Ahern <dsahern@gmail.com>
> Tested-by: Amine Kherbouche <akherbouche@scaleway.com>

Please address Sabrina's feedback and respin this series.

Thanks.

Re: [PATCH v6 1/4] udp_tunnel: add config option to bind to a device

[Alexis Bauvin]

Le 30 nov. 2018 à 15:31, Sabrina Dubroca <sd@queasysnail.net> a écrit :
> 2018-11-27, 14:05:42 +0100, Alexis Bauvin wrote:
>> diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
>> index 6539ff15e9a3..dc68e15a4f72 100644
>> --- a/net/ipv4/udp_tunnel.c
>> +++ b/net/ipv4/udp_tunnel.c
>> @@ -20,6 +20,16 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg *cfg,
>> 	if (err < 0)
>> 		goto error;
>> 
>> +	if (cfg->bind_ifindex) {
>> +		struct net_device *dev;
>> +
>> +		dev = __dev_get_by_index(net, cfg->bind_ifindex);
> 
> Quoting from net/core/dev.c:
> 
> *	[...]                                    The device has not
> *	had its reference counter increased so the caller must be careful
> *	about locking. The caller must hold either the RTNL semaphore
> *	or @dev_base_lock.
> */
> 
> which is the case for VXLAN (and GENEVE) during ndo_open, but I don't
> think other UDP tunnels (FOU, L2TP) are holding RTNL when they call
> udp_sock_create(). dev_get_by_index() + dev_put() should be safe.
> 
> Also, I don't think it's a problem with vxlan, but this could handle
> the case where __dev_get_by_index returns NULL.

First, sorry for the (late) response, thanks for the feedback!

That’s a real issue I did not take into account when writing the patch; still
too new to kernel dev.

Fixing and spinning up v7.

>> +		err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
>> +					dev->name, strlen(dev->name) + 1);
>> +		if (err < 0)
>> +			goto error;
>> +	}
>> +
>> 	udp_addr.sin_family = AF_INET;
>> 	udp_addr.sin_addr = cfg->local_ip;
>> 	udp_addr.sin_port = cfg->local_udp_port;
> 
> -- 
> Sabrina