selftests/bpf: Migrate wildcard destination rewrite test

Migrate test case from bpf/test_sock_addr.c ensuring that sendmsg
respects when sendmsg6 hooks rewrite the destination IP with the IPv6
wildcard IP, [::].

Signed-off-by: Jordan Rife <jrife@google.com>
Link: https://lore.kernel.org/r/20240510190246.3247730-10-jrife@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: jrife

tools/testing/selftests/bpf/prog_tests/sock_addr.c

@@ -448,6 +448,7 @@ BPF_SKEL_FUNCS(sendmsg6_prog, sendmsg_v6_prog);
 BPF_SKEL_FUNCS(sendmsg6_prog, sendmsg_v6_deny_prog);
 BPF_SKEL_FUNCS(sendmsg6_prog, sendmsg_v6_preserve_dst_prog);
 BPF_SKEL_FUNCS(sendmsg6_prog, sendmsg_v6_v4mapped_prog);
+BPF_SKEL_FUNCS(sendmsg6_prog, sendmsg_v6_wildcard_prog);
 BPF_SKEL_FUNCS(sendmsg_unix_prog, sendmsg_unix_prog);
 BPF_SKEL_FUNCS(recvmsg4_prog, recvmsg4_prog);
 BPF_SKEL_FUNCS(recvmsg6_prog, recvmsg6_prog);
@@ -849,6 +850,22 @@ static struct sock_addr_test tests[] = {
 		SRC6_REWRITE_IP,
 		SYSCALL_ENOTSUPP,
 	},
+	{
+		SOCK_ADDR_TEST_SENDMSG,
+		"sendmsg6: sendmsg dst IP = [::] (BSD'ism) (dgram)",
+		sendmsg_v6_wildcard_prog_load,
+		sendmsg_v6_wildcard_prog_destroy,
+		BPF_CGROUP_UDP6_SENDMSG,
+		&user_ops,
+		AF_INET6,
+		SOCK_DGRAM,
+		SERV6_IP,
+		SERV6_PORT,
+		SERV6_REWRITE_IP,
+		SERV6_REWRITE_PORT,
+		SRC6_REWRITE_IP,
+		SUCCESS,
+	},
 	{
 		SOCK_ADDR_TEST_SENDMSG,
 		"sendmsg_unix: sendmsg (dgram)",

tools/testing/selftests/bpf/progs/sendmsg6_prog.c

@@ -84,6 +84,26 @@ int sendmsg_v6_v4mapped_prog(struct bpf_sock_addr *ctx)
 	return 1;
 }
 
+SEC("cgroup/sendmsg6")
+int sendmsg_v6_wildcard_prog(struct bpf_sock_addr *ctx)
+{
+	/* Rewrite source. */
+	ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
+	ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
+	ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
+	ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
+
+	/* Rewrite destination. */
+	ctx->user_ip6[0] = bpf_htonl(0);
+	ctx->user_ip6[1] = bpf_htonl(0);
+	ctx->user_ip6[2] = bpf_htonl(0);
+	ctx->user_ip6[3] = bpf_htonl(0);
+
+	ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
+
+	return 1;
+}
+
 SEC("cgroup/sendmsg6")
 int sendmsg_v6_preserve_dst_prog(struct bpf_sock_addr *ctx)
 {

tools/testing/selftests/bpf/test_sock_addr.c

@@ -94,7 +94,6 @@ static int connect4_prog_load(const struct sock_addr_test *test);
 static int connect6_prog_load(const struct sock_addr_test *test);
 static int sendmsg4_rw_asm_prog_load(const struct sock_addr_test *test);
 static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test);
-static int sendmsg6_rw_wildcard_prog_load(const struct sock_addr_test *test);
 
 static struct sock_addr_test tests[] = {
 	/* bind */
@@ -298,20 +297,6 @@ static struct sock_addr_test tests[] = {
 		SRC6_REWRITE_IP,
 		SUCCESS,
 	},
-	{
-		"sendmsg6: set dst IP = [::] (BSD'ism)",
-		sendmsg6_rw_wildcard_prog_load,
-		BPF_CGROUP_UDP6_SENDMSG,
-		BPF_CGROUP_UDP6_SENDMSG,
-		AF_INET6,
-		SOCK_DGRAM,
-		SERV6_IP,
-		SERV6_PORT,
-		SERV6_REWRITE_IP,
-		SERV6_REWRITE_PORT,
-		SRC6_REWRITE_IP,
-		SUCCESS,
-	},
 };
 
 static int load_insns(const struct sock_addr_test *test,
@@ -497,11 +482,6 @@ static int sendmsg6_rw_asm_prog_load(const struct sock_addr_test *test)
 	return sendmsg6_rw_dst_asm_prog_load(test, SERV6_REWRITE_IP);
 }
 
-static int sendmsg6_rw_wildcard_prog_load(const struct sock_addr_test *test)
-{
-	return sendmsg6_rw_dst_asm_prog_load(test, WILDCARD6_IP);
-}
-
 static int cmp_addr(const struct sockaddr_storage *addr1,
 		    const struct sockaddr_storage *addr2, int cmp_port)
 {