[PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[Daniel Borkmann]

Allow the user to configure needed_{head,tail}room for both netkit
devices. The idea is similar to 163e529200af ("veth: implement
ndo_set_rx_headroom") with the difference that the two parameters
can be specified upon device creation. By default the current behavior
stays as is which is needed_{head,tail}room is 0.

In case of Cilium, for example, the netkit devices are not enslaved
into a bridge or openvswitch device (rather, BPF-based redirection
is used out of tcx), and as such these parameters are not propagated
into the Pod's netns via peer device.

Given Cilium can run in vxlan/geneve tunneling mode (needed_headroom)
and/or be used in combination with WireGuard (needed_{head,tail}room),
allow the Cilium CNI plugin to specify these two upon netkit device
creation.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
---
 drivers/net/netkit.c               | 66 +++++++++++++++++++-----------
 include/uapi/linux/if_link.h       |  2 +
 tools/include/uapi/linux/if_link.h |  2 +
 3 files changed, 47 insertions(+), 23 deletions(-)

diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index c1d881dc6409..fb290dcfbc96 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -338,6 +338,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
 	enum netkit_scrub scrub_peer = NETKIT_SCRUB_DEFAULT;
 	enum netkit_mode mode = NETKIT_L3;
 	unsigned char ifname_assign_type;
+	u16 headroom = 0, tailroom = 0;
 	struct ifinfomsg *ifmp = NULL;
 	struct net_device *peer;
 	char ifname[IFNAMSIZ];
@@ -371,6 +372,10 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
 			if (err < 0)
 				return err;
 		}
+		if (data[IFLA_NETKIT_HEADROOM])
+			headroom = nla_get_u16(data[IFLA_NETKIT_HEADROOM]);
+		if (data[IFLA_NETKIT_TAILROOM])
+			tailroom = nla_get_u16(data[IFLA_NETKIT_TAILROOM]);
 	}
 
 	if (ifmp && tbp[IFLA_IFNAME]) {
@@ -390,6 +395,14 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
 		return PTR_ERR(peer);
 
 	netif_inherit_tso_max(peer, dev);
+	if (headroom) {
+		peer->needed_headroom = headroom;
+		dev->needed_headroom = headroom;
+	}
+	if (tailroom) {
+		peer->needed_tailroom = tailroom;
+		dev->needed_tailroom = tailroom;
+	}
 
 	if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS]))
 		eth_hw_addr_random(peer);
@@ -401,6 +414,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
 	nk->policy = policy_peer;
 	nk->scrub = scrub_peer;
 	nk->mode = mode;
+	nk->headroom = headroom;
 	bpf_mprog_bundle_init(&nk->bundle);
 
 	err = register_netdevice(peer);
@@ -426,6 +440,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
 	nk->policy = policy_prim;
 	nk->scrub = scrub_prim;
 	nk->mode = mode;
+	nk->headroom = headroom;
 	bpf_mprog_bundle_init(&nk->bundle);
 
 	err = register_netdevice(dev);
@@ -850,7 +865,18 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
 	struct net_device *peer = rtnl_dereference(nk->peer);
 	enum netkit_action policy;
 	struct nlattr *attr;
-	int err;
+	int err, i;
+	struct {
+		u32 attr;
+		char *name;
+	} fixed_params[] = {
+		{ IFLA_NETKIT_MODE,       "operating mode" },
+		{ IFLA_NETKIT_SCRUB,      "scrubbing" },
+		{ IFLA_NETKIT_PEER_SCRUB, "peer scrubbing" },
+		{ IFLA_NETKIT_PEER_INFO,  "peer info" },
+		{ IFLA_NETKIT_HEADROOM,   "headroom" },
+		{ IFLA_NETKIT_TAILROOM,   "tailroom" },
+	};
 
 	if (!nk->primary) {
 		NL_SET_ERR_MSG(extack,
@@ -858,28 +884,14 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
 		return -EACCES;
 	}
 
-	if (data[IFLA_NETKIT_MODE]) {
-		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE],
-				    "netkit link operating mode cannot be changed after device creation");
-		return -EACCES;
-	}
-
-	if (data[IFLA_NETKIT_SCRUB]) {
-		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_SCRUB],
-				    "netkit scrubbing cannot be changed after device creation");
-		return -EACCES;
-	}
-
-	if (data[IFLA_NETKIT_PEER_SCRUB]) {
-		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_SCRUB],
-				    "netkit scrubbing cannot be changed after device creation");
-		return -EACCES;
-	}
-
-	if (data[IFLA_NETKIT_PEER_INFO]) {
-		NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO],
-				    "netkit peer info cannot be changed after device creation");
-		return -EINVAL;
+	for (i = 0; i < ARRAY_SIZE(fixed_params); i++) {
+		attr = data[fixed_params[i].attr];
+		if (attr) {
+			NL_SET_ERR_MSG_ATTR_FMT(extack, attr,
+						"netkit link %s cannot be changed after device creation",
+						fixed_params[i].name);
+			return -EACCES;
+		}
 	}
 
 	if (data[IFLA_NETKIT_POLICY]) {
@@ -914,6 +926,8 @@ static size_t netkit_get_size(const struct net_device *dev)
 	       nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_SCRUB */
 	       nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */
 	       nla_total_size(sizeof(u8))  + /* IFLA_NETKIT_PRIMARY */
+	       nla_total_size(sizeof(u16)) + /* IFLA_NETKIT_HEADROOM */
+	       nla_total_size(sizeof(u16)) + /* IFLA_NETKIT_TAILROOM */
 	       0;
 }
 
@@ -930,6 +944,10 @@ static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
 		return -EMSGSIZE;
 	if (nla_put_u32(skb, IFLA_NETKIT_SCRUB, nk->scrub))
 		return -EMSGSIZE;
+	if (nla_put_u16(skb, IFLA_NETKIT_HEADROOM, dev->needed_headroom))
+		return -EMSGSIZE;
+	if (nla_put_u16(skb, IFLA_NETKIT_TAILROOM, dev->needed_tailroom))
+		return -EMSGSIZE;
 
 	if (peer) {
 		nk = netkit_priv(peer);
@@ -947,6 +965,8 @@ static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
 	[IFLA_NETKIT_MODE]		= NLA_POLICY_MAX(NLA_U32, NETKIT_L3),
 	[IFLA_NETKIT_POLICY]		= { .type = NLA_U32 },
 	[IFLA_NETKIT_PEER_POLICY]	= { .type = NLA_U32 },
+	[IFLA_NETKIT_HEADROOM]		= { .type = NLA_U16 },
+	[IFLA_NETKIT_TAILROOM]		= { .type = NLA_U16 },
 	[IFLA_NETKIT_SCRUB]		= NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
 	[IFLA_NETKIT_PEER_SCRUB]	= NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
 	[IFLA_NETKIT_PRIMARY]		= { .type = NLA_REJECT,
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 2575e0cd9b48..2fa2c265dcba 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1315,6 +1315,8 @@ enum {
 	IFLA_NETKIT_MODE,
 	IFLA_NETKIT_SCRUB,
 	IFLA_NETKIT_PEER_SCRUB,
+	IFLA_NETKIT_HEADROOM,
+	IFLA_NETKIT_TAILROOM,
 	__IFLA_NETKIT_MAX,
 };
 #define IFLA_NETKIT_MAX	(__IFLA_NETKIT_MAX - 1)
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index 8516c1ccd57a..7e46ca4cd31b 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h
@@ -1315,6 +1315,8 @@ enum {
 	IFLA_NETKIT_MODE,
 	IFLA_NETKIT_SCRUB,
 	IFLA_NETKIT_PEER_SCRUB,
+	IFLA_NETKIT_HEADROOM,
+	IFLA_NETKIT_TAILROOM,
 	__IFLA_NETKIT_MAX,
 };
 #define IFLA_NETKIT_MAX	(__IFLA_NETKIT_MAX - 1)
-- 
2.43.0

[PATCH bpf-next 2/3] netkit: Add add netkit {head,tail}room to rt_link.yaml

[Daniel Borkmann]

Add netkit {head,tail}room attribute support to the rt_link.yaml spec file.

Example:

  # ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/rt_link.yaml \
   --do getlink --json '{"ifname": "nk0"}' --output-json | jq
  [...]
  "linkinfo": {
    "kind": "netkit",
    "data": {
    }
  },
  [...]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
---
 Documentation/netlink/specs/rt_link.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/netlink/specs/rt_link.yaml b/Documentation/netlink/specs/rt_link.yaml
index 9ffa13b77dcf..dbeae6b1c548 100644
--- a/Documentation/netlink/specs/rt_link.yaml
+++ b/Documentation/netlink/specs/rt_link.yaml
@@ -2166,6 +2166,12 @@ attribute-sets:
         name: peer-scrub
         type: u32
         enum: netkit-scrub
+      -
+        name: headroom
+        type: u16
+      -
+        name: tailroom
+        type: u16
 
 sub-messages:
   -
-- 
2.43.0

Re: [PATCH bpf-next 2/3] netkit: Add add netkit {head,tail}room to rt_link.yaml

[Nikolay Aleksandrov]

On 12/19/24 19:39, Daniel Borkmann wrote:
> Add netkit {head,tail}room attribute support to the rt_link.yaml spec file.
> 
> Example:
> 
>   # ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/rt_link.yaml \
>    --do getlink --json '{"ifname": "nk0"}' --output-json | jq
>   [...]
>   "linkinfo": {
>     "kind": "netkit",
>     "data": {
>     }
>   },
>   [...]
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Nikolay Aleksandrov <razor@blackwall.org>
> ---
>  Documentation/netlink/specs/rt_link.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/netlink/specs/rt_link.yaml b/Documentation/netlink/specs/rt_link.yaml
> index 9ffa13b77dcf..dbeae6b1c548 100644
> --- a/Documentation/netlink/specs/rt_link.yaml
> +++ b/Documentation/netlink/specs/rt_link.yaml
> @@ -2166,6 +2166,12 @@ attribute-sets:
>          name: peer-scrub
>          type: u32
>          enum: netkit-scrub
> +      -
> +        name: headroom
> +        type: u16
> +      -
> +        name: tailroom
> +        type: u16
>  
>  sub-messages:
>    -

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

[PATCH bpf-next 3/3] selftests/bpf: Extend netkit tests to validate set {head,tail}room

[Daniel Borkmann]

Extend the netkit selftests to specify and validate the {head,tail}room
on the netdevice:

  # ./vmtest.sh -- ./test_progs -t netkit
  [...]
  ./test_progs -t netkit
  [    1.174147] bpf_testmod: loading out-of-tree module taints kernel.
  [    1.174585] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
  [    1.422307] tsc: Refined TSC clocksource calibration: 3407.983 MHz
  [    1.424511] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc3e5084, max_idle_ns: 440795359833 ns
  [    1.428092] clocksource: Switched to clocksource tsc
  #363     tc_netkit_basic:OK
  #364     tc_netkit_device:OK
  #365     tc_netkit_multi_links:OK
  #366     tc_netkit_multi_opts:OK
  #367     tc_netkit_neigh_links:OK
  #368     tc_netkit_pkt_type:OK
  #369     tc_netkit_scrub:OK
  Summary: 7/0 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
---
 .../selftests/bpf/prog_tests/tc_netkit.c      | 31 ++++++++++++-------
 .../selftests/bpf/progs/test_tc_link.c        | 15 +++++++++
 2 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/tc_netkit.c b/tools/testing/selftests/bpf/prog_tests/tc_netkit.c
index 151a4210028f..7e41dceec58d 100644
--- a/tools/testing/selftests/bpf/prog_tests/tc_netkit.c
+++ b/tools/testing/selftests/bpf/prog_tests/tc_netkit.c
@@ -14,6 +14,9 @@
 #include "netlink_helpers.h"
 #include "tc_helpers.h"
 
+#define NETKIT_HEADROOM	32
+#define NETKIT_TAILROOM	8
+
 #define MARK		42
 #define PRIO		0xeb9f
 #define ICMP_ECHO	8
@@ -35,7 +38,7 @@ struct iplink_req {
 };
 
 static int create_netkit(int mode, int policy, int peer_policy, int *ifindex,
-			 bool same_netns, int scrub, int peer_scrub)
+			 bool same_netns, int scrub, int peer_scrub, bool room)
 {
 	struct rtnl_handle rth = { .fd = -1 };
 	struct iplink_req req = {};
@@ -63,6 +66,10 @@ static int create_netkit(int mode, int policy, int peer_policy, int *ifindex,
 	addattr32(&req.n, sizeof(req), IFLA_NETKIT_SCRUB, scrub);
 	addattr32(&req.n, sizeof(req), IFLA_NETKIT_PEER_SCRUB, peer_scrub);
 	addattr32(&req.n, sizeof(req), IFLA_NETKIT_MODE, mode);
+	if (room) {
+		addattr16(&req.n, sizeof(req), IFLA_NETKIT_HEADROOM, NETKIT_HEADROOM);
+		addattr16(&req.n, sizeof(req), IFLA_NETKIT_TAILROOM, NETKIT_TAILROOM);
+	}
 	addattr_nest_end(&req.n, data);
 	addattr_nest_end(&req.n, linkinfo);
 
@@ -185,7 +192,7 @@ void serial_test_tc_netkit_basic(void)
 
 	err = create_netkit(NETKIT_L2, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, false, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -300,7 +307,7 @@ static void serial_test_tc_netkit_multi_links_target(int mode, int target)
 
 	err = create_netkit(mode, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, false, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -429,7 +436,7 @@ static void serial_test_tc_netkit_multi_opts_target(int mode, int target)
 
 	err = create_netkit(mode, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, false, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -544,7 +551,7 @@ void serial_test_tc_netkit_device(void)
 
 	err = create_netkit(NETKIT_L3, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, true, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -656,7 +663,7 @@ static void serial_test_tc_netkit_neigh_links_target(int mode, int target)
 
 	err = create_netkit(mode, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, false, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -734,7 +741,7 @@ static void serial_test_tc_netkit_pkt_type_mode(int mode)
 
 	err = create_netkit(mode, NETKIT_PASS, NETKIT_PASS,
 			    &ifindex, true, NETKIT_SCRUB_DEFAULT,
-			    NETKIT_SCRUB_DEFAULT);
+			    NETKIT_SCRUB_DEFAULT, false);
 	if (err)
 		return;
 
@@ -799,7 +806,7 @@ void serial_test_tc_netkit_pkt_type(void)
 	serial_test_tc_netkit_pkt_type_mode(NETKIT_L3);
 }
 
-static void serial_test_tc_netkit_scrub_type(int scrub)
+static void serial_test_tc_netkit_scrub_type(int scrub, bool room)
 {
 	LIBBPF_OPTS(bpf_netkit_opts, optl);
 	struct test_tc_link *skel;
@@ -807,7 +814,7 @@ static void serial_test_tc_netkit_scrub_type(int scrub)
 	int err, ifindex;
 
 	err = create_netkit(NETKIT_L2, NETKIT_PASS, NETKIT_PASS,
-			    &ifindex, false, scrub, scrub);
+			    &ifindex, false, scrub, scrub, room);
 	if (err)
 		return;
 
@@ -842,6 +849,8 @@ static void serial_test_tc_netkit_scrub_type(int scrub)
 	ASSERT_EQ(skel->bss->seen_tc8, true, "seen_tc8");
 	ASSERT_EQ(skel->bss->mark, scrub == NETKIT_SCRUB_NONE ? MARK : 0, "mark");
 	ASSERT_EQ(skel->bss->prio, scrub == NETKIT_SCRUB_NONE ? PRIO : 0, "prio");
+	ASSERT_EQ(skel->bss->headroom, room ? NETKIT_HEADROOM : 0, "headroom");
+	ASSERT_EQ(skel->bss->tailroom, room ? NETKIT_TAILROOM : 0, "tailroom");
 cleanup:
 	test_tc_link__destroy(skel);
 
@@ -852,6 +861,6 @@ static void serial_test_tc_netkit_scrub_type(int scrub)
 
 void serial_test_tc_netkit_scrub(void)
 {
-	serial_test_tc_netkit_scrub_type(NETKIT_SCRUB_DEFAULT);
-	serial_test_tc_netkit_scrub_type(NETKIT_SCRUB_NONE);
+	serial_test_tc_netkit_scrub_type(NETKIT_SCRUB_DEFAULT, false);
+	serial_test_tc_netkit_scrub_type(NETKIT_SCRUB_NONE, true);
 }
diff --git a/tools/testing/selftests/bpf/progs/test_tc_link.c b/tools/testing/selftests/bpf/progs/test_tc_link.c
index 10d825928499..630f12e51b07 100644
--- a/tools/testing/selftests/bpf/progs/test_tc_link.c
+++ b/tools/testing/selftests/bpf/progs/test_tc_link.c
@@ -8,6 +8,7 @@
 #include <linux/if_packet.h>
 #include <bpf/bpf_endian.h>
 #include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
 
 char LICENSE[] SEC("license") = "GPL";
 
@@ -27,6 +28,7 @@ bool seen_host;
 bool seen_mcast;
 
 int mark, prio;
+unsigned short headroom, tailroom;
 
 SEC("tc/ingress")
 int tc1(struct __sk_buff *skb)
@@ -104,11 +106,24 @@ int tc7(struct __sk_buff *skb)
 	return TCX_PASS;
 }
 
+struct sk_buff {
+	struct net_device *dev;
+};
+
+struct net_device {
+	unsigned short needed_headroom;
+	unsigned short needed_tailroom;
+};
+
 SEC("tc/egress")
 int tc8(struct __sk_buff *skb)
 {
+	struct net_device *dev = BPF_CORE_READ((struct sk_buff *)skb, dev);
+
 	seen_tc8 = true;
 	mark = skb->mark;
 	prio = skb->priority;
+	headroom = BPF_CORE_READ(dev, needed_headroom);
+	tailroom = BPF_CORE_READ(dev, needed_tailroom);
 	return TCX_PASS;
 }
-- 
2.43.0

Re: [PATCH bpf-next 3/3] selftests/bpf: Extend netkit tests to validate set {head,tail}room

[Nikolay Aleksandrov]

On 12/19/24 19:39, Daniel Borkmann wrote:
> Extend the netkit selftests to specify and validate the {head,tail}room
> on the netdevice:
> 
>   # ./vmtest.sh -- ./test_progs -t netkit
>   [...]
>   ./test_progs -t netkit
>   [    1.174147] bpf_testmod: loading out-of-tree module taints kernel.
>   [    1.174585] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
>   [    1.422307] tsc: Refined TSC clocksource calibration: 3407.983 MHz
>   [    1.424511] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc3e5084, max_idle_ns: 440795359833 ns
>   [    1.428092] clocksource: Switched to clocksource tsc
>   #363     tc_netkit_basic:OK
>   #364     tc_netkit_device:OK
>   #365     tc_netkit_multi_links:OK
>   #366     tc_netkit_multi_opts:OK
>   #367     tc_netkit_neigh_links:OK
>   #368     tc_netkit_pkt_type:OK
>   #369     tc_netkit_scrub:OK
>   Summary: 7/0 PASSED, 0 SKIPPED, 0 FAILED
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Nikolay Aleksandrov <razor@blackwall.org>
> ---
>  .../selftests/bpf/prog_tests/tc_netkit.c      | 31 ++++++++++++-------
>  .../selftests/bpf/progs/test_tc_link.c        | 15 +++++++++
>  2 files changed, 35 insertions(+), 11 deletions(-)
> 

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

Re: [PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[Jakub Kicinski]

On Thu, 19 Dec 2024 18:39:26 +0100 Daniel Borkmann wrote:
> +	if (headroom) {
> +		peer->needed_headroom = headroom;
> +		dev->needed_headroom = headroom;
> +	}
> +	if (tailroom) {
> +		peer->needed_tailroom = tailroom;
> +		dev->needed_tailroom = tailroom;
> +	}

Since you use the same one for main dev and peer should there be
something rejecting the use of the new attr in the peer attrs?
(IFLA_NETKIT_PEER_INFO)

> +	struct {

static const?

I wish more userspace learned how to do reverse parsing.
We wouldn't have to bother injecting the attr names to all the messages,
NL_SET_ERR_MSG_ATTR() already points to the attr :|

Re: [PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[Daniel Borkmann]

On 12/20/24 3:23 AM, Jakub Kicinski wrote:
> On Thu, 19 Dec 2024 18:39:26 +0100 Daniel Borkmann wrote:
>> +	if (headroom) {
>> +		peer->needed_headroom = headroom;
>> +		dev->needed_headroom = headroom;
>> +	}
>> +	if (tailroom) {
>> +		peer->needed_tailroom = tailroom;
>> +		dev->needed_tailroom = tailroom;
>> +	}
> 
> Since you use the same one for main dev and peer should there be
> something rejecting the use of the new attr in the peer attrs?
> (IFLA_NETKIT_PEER_INFO)

The peer info is parsed via rtnl_nla_parse_ifinfomsg() which internally
uses ifla_policy filter where IFLA_INFO_DATA is not part of, but to be
sure I can add one more selftest case to confirm.

>> +	struct {
> 
> static const?

Ack, will change.

Thanks,
Daniel

Re: [PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[Daniel Borkmann]

On 12/20/24 10:06 AM, Daniel Borkmann wrote:
> On 12/20/24 3:23 AM, Jakub Kicinski wrote:
>> On Thu, 19 Dec 2024 18:39:26 +0100 Daniel Borkmann wrote:
>>> +    if (headroom) {
>>> +        peer->needed_headroom = headroom;
>>> +        dev->needed_headroom = headroom;
>>> +    }
>>> +    if (tailroom) {
>>> +        peer->needed_tailroom = tailroom;
>>> +        dev->needed_tailroom = tailroom;
>>> +    }
>>
>> Since you use the same one for main dev and peer should there be
>> something rejecting the use of the new attr in the peer attrs?
>> (IFLA_NETKIT_PEER_INFO)
> 
> The peer info is parsed via rtnl_nla_parse_ifinfomsg() which internally
> uses ifla_policy filter where IFLA_INFO_DATA is not part of, but to be
> sure I can add one more selftest case to confirm.

Looks like we don't bail out anymore after the conversion in fefd5d082172
("netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type."), so I
left it out for now from the series.. need to experiment some more whether
fefd5d082172 dropping the error has any unintended side-effects. But I'm
currently not seeing how it would be much different to, for example, the
preceding netif_inherit_tso_max() call.

Thanks,
Daniel

Re: [PATCH bpf-next 1/3] netkit: Allow for configuring needed_{head,tail}room

[Nikolay Aleksandrov]

On 12/19/24 19:39, Daniel Borkmann wrote:
> Allow the user to configure needed_{head,tail}room for both netkit
> devices. The idea is similar to 163e529200af ("veth: implement
> ndo_set_rx_headroom") with the difference that the two parameters
> can be specified upon device creation. By default the current behavior
> stays as is which is needed_{head,tail}room is 0.
> 
> In case of Cilium, for example, the netkit devices are not enslaved
> into a bridge or openvswitch device (rather, BPF-based redirection
> is used out of tcx), and as such these parameters are not propagated
> into the Pod's netns via peer device.
> 
> Given Cilium can run in vxlan/geneve tunneling mode (needed_headroom)
> and/or be used in combination with WireGuard (needed_{head,tail}room),
> allow the Cilium CNI plugin to specify these two upon netkit device
> creation.
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Nikolay Aleksandrov <razor@blackwall.org>
> ---
>  drivers/net/netkit.c               | 66 +++++++++++++++++++-----------
>  include/uapi/linux/if_link.h       |  2 +
>  tools/include/uapi/linux/if_link.h |  2 +
>  3 files changed, 47 insertions(+), 23 deletions(-)
> 

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