Subject: [PATCH bpf,v2 1/4] bpf: factor out socket lookup functions for the TC hookpoint.

From: Gilad Sever <[email-masked]>
Date: Thu, 20 Apr 2023 17:50:38 +0300

Change BPF helper socket lookup functions to use TC specific variants:
bpf_tc_sk_lookup_tcp() / bpf_tc_sk_lookup_udp() / bpf_tc_skc_lookup_tcp()
instead of sharing implementation with the cg / sk_skb hooking points.
This allows introducing a separate logic for the TC flow.

The tc functions are identical to the original code.

Signed-off-by: Gilad Sever <[email-masked]>
---
 net/core/filter.c | 63 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 3 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 1d6f165923bf..5910956f4e0d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6701,6 +6701,63 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
 	.arg5_type	= ARG_ANYTHING,
 };
 
+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);
+}
+
+static const struct bpf_func_proto bpf_tc_skc_lookup_tcp_proto = {
+	.func		= bpf_tc_skc_lookup_tcp,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_PTR_TO_SOCK_COMMON_OR_NULL,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+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);
+}
+
+static const struct bpf_func_proto bpf_tc_sk_lookup_tcp_proto = {
+	.func		= bpf_tc_sk_lookup_tcp,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_PTR_TO_SOCKET_OR_NULL,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
+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);
+}
+
+static const struct bpf_func_proto bpf_tc_sk_lookup_udp_proto = {
+	.func		= bpf_tc_sk_lookup_udp,
+	.gpl_only	= false,
+	.pkt_access	= true,
+	.ret_type	= RET_PTR_TO_SOCKET_OR_NULL,
+	.arg1_type	= ARG_PTR_TO_CTX,
+	.arg2_type	= ARG_PTR_TO_MEM | MEM_RDONLY,
+	.arg3_type	= ARG_CONST_SIZE,
+	.arg4_type	= ARG_ANYTHING,
+	.arg5_type	= ARG_ANYTHING,
+};
+
 BPF_CALL_1(bpf_sk_release, struct sock *, sk)
 {
 	if (sk && sk_is_refcounted(sk))
@@ -7954,9 +8011,9 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 #endif
 #ifdef CONFIG_INET
 	case BPF_FUNC_sk_lookup_tcp:
-		return &bpf_sk_lookup_tcp_proto;
+		return &bpf_tc_sk_lookup_tcp_proto;
 	case BPF_FUNC_sk_lookup_udp:
-		return &bpf_sk_lookup_udp_proto;
+		return &bpf_tc_sk_lookup_udp_proto;
 	case BPF_FUNC_sk_release:
 		return &bpf_sk_release_proto;
 	case BPF_FUNC_tcp_sock:
@@ -7964,7 +8021,7 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
 	case BPF_FUNC_get_listener_sock:
 		return &bpf_get_listener_sock_proto;
 	case BPF_FUNC_skc_lookup_tcp:
-		return &bpf_skc_lookup_tcp_proto;
+		return &bpf_tc_skc_lookup_tcp_proto;
 	case BPF_FUNC_tcp_check_syncookie:
 		return &bpf_tcp_check_syncookie_proto;
 	case BPF_FUNC_skb_ecn_set_ce:
-- 
2.34.1