On 04/26, Gilad Sever wrote:
When calling bpf_sk_lookup_tcp(), bpf_sk_lookup_udp() or bpf_skc_lookup_tcp() from tc/xdp ingress, VRF socket bindings aren't respoected, i.e. unbound sockets are returned, and bound sockets aren't found.
VRF binding is determined by the sdif argument to sk_lookup(), however when called from tc the IP SKB control block isn't initialized and thus inet{,6}_sdif() always returns 0.
Fix by calculating sdif for the tc/xdp flows by observing the device's l3 enslaved state.
The cg/sk_skb hooking points which are expected to support inet{,6}_sdif() pass sdif=-1 which makes __bpf_skc_lookup() use the existing logic.
Fixes: 6acc9b432e67 ("bpf: Add helper to retrieve socket in BPF") Reviewed-by: Shmulik Ladkani shmulik.ladkani@gmail.com Reviewed-by: Eyal Birger eyal.birger@gmail.com Signed-off-by: Gilad Sever gilad9366@gmail.com
Acked-by: Stanislav Fomichev sdf@google.com
with one nit below
v3: Rename bpf_l2_sdif() to dev_sdif() as suggested by Stanislav Fomichev
net/core/filter.c | 63 +++++++++++++++++++++++++++++++---------------- 1 file changed, 42 insertions(+), 21 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c index f43f86fc1235..894913aaa29f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6529,12 +6529,11 @@ static struct sock *sk_lookup(struct net *net, struct bpf_sock_tuple *tuple, static struct sock * __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
u64 flags)
u64 flags, int sdif){ struct sock *sk = NULL; struct net *net; u8 family;
- int sdif;
if (len == sizeof(tuple->ipv4)) family = AF_INET; @@ -6546,10 +6545,12 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, if (unlikely(flags || !((s32)netns_id < 0 || netns_id <= S32_MAX))) goto out;
- if (family == AF_INET)
sdif = inet_sdif(skb);- else
sdif = inet6_sdif(skb);
- if (sdif < 0) {
if (family == AF_INET)sdif = inet_sdif(skb);elsesdif = inet6_sdif(skb);- }
if ((s32)netns_id < 0) { net = caller_net; @@ -6569,10 +6570,11 @@ __bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, static struct sock * __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, struct net *caller_net, u32 ifindex, u8 proto, u64 netns_id,
u64 flags)
u64 flags, int sdif){ struct sock *sk = __bpf_skc_lookup(skb, tuple, len, caller_net,
ifindex, proto, netns_id, flags);
ifindex, proto, netns_id, flags,sdif);if (sk) { struct sock *sk2 = sk_to_full_sk(sk); @@ -6612,7 +6614,7 @@ bpf_skc_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, } return __bpf_skc_lookup(skb, tuple, len, caller_net, ifindex, proto,
netns_id, flags);
netns_id, flags, -1);} static struct sock * @@ -6701,15 +6703,25 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = { .arg5_type = ARG_ANYTHING, };
[..]
+static int dev_sdif(const struct net_device *dev) +{ +#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
- if (netif_is_l3_slave(dev))
return dev->ifindex;+#endif
- return 0;
+}
nit: should this go into include/linux/netdevice.h?
BPF_CALL_5(bpf_tc_skc_lookup_tcp, struct sk_buff *, skb, struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) { struct net *caller_net = dev_net(skb->dev);
- int sdif = dev_sdif(skb->dev); int ifindex = skb->dev->ifindex;
return (unsigned long)__bpf_skc_lookup(skb, tuple, len, caller_net, ifindex, IPPROTO_TCP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_tc_skc_lookup_tcp_proto = { @@ -6728,11 +6740,12 @@ BPF_CALL_5(bpf_tc_sk_lookup_tcp, struct sk_buff *, skb, struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) { struct net *caller_net = dev_net(skb->dev);
- int sdif = dev_sdif(skb->dev); int ifindex = skb->dev->ifindex;
return (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net, ifindex, IPPROTO_TCP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_tc_sk_lookup_tcp_proto = { @@ -6751,11 +6764,12 @@ BPF_CALL_5(bpf_tc_sk_lookup_udp, struct sk_buff *, skb, struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) { struct net *caller_net = dev_net(skb->dev);
- int sdif = dev_sdif(skb->dev); int ifindex = skb->dev->ifindex;
return (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net, ifindex, IPPROTO_UDP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_tc_sk_lookup_udp_proto = { @@ -6788,11 +6802,13 @@ BPF_CALL_5(bpf_xdp_sk_lookup_udp, struct xdp_buff *, ctx, struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags) { struct net *caller_net = dev_net(ctx->rxq->dev);
- int ifindex = ctx->rxq->dev->ifindex;
- struct net_device *dev = ctx->rxq->dev;
- int sdif = dev_sdif(dev);
- int ifindex = dev->ifindex;
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex, IPPROTO_UDP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_xdp_sk_lookup_udp_proto = { @@ -6811,11 +6827,13 @@ BPF_CALL_5(bpf_xdp_skc_lookup_tcp, struct xdp_buff *, ctx, struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags) { struct net *caller_net = dev_net(ctx->rxq->dev);
- int ifindex = ctx->rxq->dev->ifindex;
- struct net_device *dev = ctx->rxq->dev;
- int sdif = dev_sdif(dev);
- int ifindex = dev->ifindex;
return (unsigned long)__bpf_skc_lookup(NULL, tuple, len, caller_net, ifindex, IPPROTO_TCP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_xdp_skc_lookup_tcp_proto = { @@ -6834,11 +6852,13 @@ BPF_CALL_5(bpf_xdp_sk_lookup_tcp, struct xdp_buff *, ctx, struct bpf_sock_tuple *, tuple, u32, len, u32, netns_id, u64, flags) { struct net *caller_net = dev_net(ctx->rxq->dev);
- int ifindex = ctx->rxq->dev->ifindex;
- struct net_device *dev = ctx->rxq->dev;
- int sdif = dev_sdif(dev);
- int ifindex = dev->ifindex;
return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, caller_net, ifindex, IPPROTO_TCP, netns_id,
flags);
flags, sdif);} static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = { @@ -6858,7 +6878,8 @@ BPF_CALL_5(bpf_sock_addr_skc_lookup_tcp, struct bpf_sock_addr_kern *, ctx, { return (unsigned long)__bpf_skc_lookup(NULL, tuple, len, sock_net(ctx->sk), 0,
IPPROTO_TCP, netns_id, flags);
IPPROTO_TCP, netns_id, flags,-1);} static const struct bpf_func_proto bpf_sock_addr_skc_lookup_tcp_proto = { @@ -6877,7 +6898,7 @@ BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx, { return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0, IPPROTO_TCP,
netns_id, flags);
netns_id, flags, -1);} static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = { @@ -6896,7 +6917,7 @@ BPF_CALL_5(bpf_sock_addr_sk_lookup_udp, struct bpf_sock_addr_kern *, ctx, { return (unsigned long)__bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0, IPPROTO_UDP,
netns_id, flags);
netns_id, flags, -1);} static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = { -- 2.34.1