Subject: [PATCH bpf,v2 2/4] bpf: Call __bpf_sk_lookup()/__bpf_skc_lookup() directly via TC hookpoint

From: Gilad Sever <[email-masked]>
Date: Thu, 20 Apr 2023 17:50:39 +0300

skb->dev always exists in the tc flow. There is no need to use
bpf_skc_lookup(), bpf_sk_lookup() from this code path.

This change facilitates fixing the tc flow to be VRF aware.

Signed-off-by: Gilad Sever <[email-masked]>
---
 net/core/filter.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 5910956f4e0d..f43f86fc1235 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6704,8 +6704,12 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
 BPF_CALL_5(bpf_tc_skc_lookup_tcp, struct sk_buff *, skb,
 	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
 {
-	return (unsigned long)bpf_skc_lookup(skb, tuple, len, IPPROTO_TCP,
-					     netns_id, flags);
+	struct net *caller_net = dev_net(skb->dev);
+	int ifindex = skb->dev->ifindex;
+
+	return (unsigned long)__bpf_skc_lookup(skb, tuple, len, caller_net,
+					       ifindex, IPPROTO_TCP, netns_id,
+					       flags);
 }
 
 static const struct bpf_func_proto bpf_tc_skc_lookup_tcp_proto = {
@@ -6723,8 +6727,12 @@ static const struct bpf_func_proto bpf_tc_skc_lookup_tcp_proto = {
 BPF_CALL_5(bpf_tc_sk_lookup_tcp, struct sk_buff *, skb,
 	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
 {
-	return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_TCP,
-					    netns_id, flags);
+	struct net *caller_net = dev_net(skb->dev);
+	int ifindex = skb->dev->ifindex;
+
+	return (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net,
+					      ifindex, IPPROTO_TCP, netns_id,
+					      flags);
 }
 
 static const struct bpf_func_proto bpf_tc_sk_lookup_tcp_proto = {
@@ -6742,8 +6750,12 @@ static const struct bpf_func_proto bpf_tc_sk_lookup_tcp_proto = {
 BPF_CALL_5(bpf_tc_sk_lookup_udp, struct sk_buff *, skb,
 	   struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags)
 {
-	return (unsigned long)bpf_sk_lookup(skb, tuple, len, IPPROTO_UDP,
-					    netns_id, flags);
+	struct net *caller_net = dev_net(skb->dev);
+	int ifindex = skb->dev->ifindex;
+
+	return (unsigned long)__bpf_sk_lookup(skb, tuple, len, caller_net,
+					      ifindex, IPPROTO_UDP, netns_id,
+					      flags);
 }
 
 static const struct bpf_func_proto bpf_tc_sk_lookup_udp_proto = {
-- 
2.34.1