1 files changed, 36 insertions, 9 deletions

diff --git a/tools/testing/selftests/bpf/connect4_prog.c b/tools/testing/selftests/bpf/connect4_prog.c
index 5a88a681d2ab..1fd244d35ba9 100644
--- a/tools/testing/selftests/bpf/connect4_prog.c
+++ b/tools/testing/selftests/bpf/connect4_prog.c
@@ -21,23 +21,50 @@ int _version SEC("version") = 1;
 SEC("cgroup/connect4")
 int connect_v4_prog(struct bpf_sock_addr *ctx)
 {
+	struct bpf_sock_tuple tuple = {};
 	struct sockaddr_in sa;
+	struct bpf_sock *sk;
+
+	/* Verify that new destination is available. */
+	memset(&tuple.ipv4.saddr, 0, sizeof(tuple.ipv4.saddr));
+	memset(&tuple.ipv4.sport, 0, sizeof(tuple.ipv4.sport));
+
+	tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4);
+	tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4);
+
+	if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
+		return 0;
+	else if (ctx->type == SOCK_STREAM)
+		sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv4),
+				       BPF_F_CURRENT_NETNS, 0);
+	else
+		sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv4),
+				       BPF_F_CURRENT_NETNS, 0);
+
+	if (!sk)
+		return 0;
+
+	if (sk->src_ip4 != tuple.ipv4.daddr ||
+	    sk->src_port != DST_REWRITE_PORT4) {
+		bpf_sk_release(sk);
+		return 0;
+	}
+
+	bpf_sk_release(sk);
 
 	/* Rewrite destination. */
 	ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
 	ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
 
-	if (ctx->type == SOCK_DGRAM || ctx->type == SOCK_STREAM) {
-		///* Rewrite source. */
-		memset(&sa, 0, sizeof(sa));
+	/* Rewrite source. */
+	memset(&sa, 0, sizeof(sa));
 
-		sa.sin_family = AF_INET;
-		sa.sin_port = bpf_htons(0);
-		sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
+	sa.sin_family = AF_INET;
+	sa.sin_port = bpf_htons(0);
+	sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
 
-		if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
-			return 0;
-	}
+	if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
+		return 0;
 
 	return 1;
 }