selftests/bpf: Use sockaddr_storage instead of sa46 in select_reuseport test

The select_reuseport selftest uses a custom sa46 union to represent
IPv4 and IPv6 addresses. This custom wrapper requires extra manual
handling for address family and field extraction.

Replace sa46 with sockaddr_storage and update the helper functions to
operate on native socket structures. This simplifies the code and
removes unnecessary custom address-handling logic. No functional
changes intended.

Reviewed-by: Amery Hung <[email protected]>
Signed-off-by: Hoyeon Lee <[email protected]>
Signed-off-by: Martin KaFai Lau <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: HoyeonRhee

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

@@ -41,11 +41,7 @@ static struct bpf_object *obj;
 static __u32 index_zero;
 static int epfd;
 
-static union sa46 {
-	struct sockaddr_in6 v6;
-	struct sockaddr_in v4;
-	sa_family_t family;
-} srv_sa;
+static struct sockaddr_storage srv_sa;
 
 #define RET_IF(condition, tag, format...) ({				\
 	if (CHECK_FAIL(condition)) {					\
@@ -135,24 +131,24 @@ static int prepare_bpf_obj(void)
 	return 0;
 }
 
-static void sa46_init_loopback(union sa46 *sa, sa_family_t family)
+static void ss_init_loopback(struct sockaddr_storage *sa, sa_family_t family)
 {
 	memset(sa, 0, sizeof(*sa));
-	sa->family = family;
-	if (sa->family == AF_INET6)
-		sa->v6.sin6_addr = in6addr_loopback;
+	sa->ss_family = family;
+	if (sa->ss_family == AF_INET6)
+		((struct sockaddr_in6 *)sa)->sin6_addr = in6addr_loopback;
 	else
-		sa->v4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+		((struct sockaddr_in *)sa)->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
 }
 
-static void sa46_init_inany(union sa46 *sa, sa_family_t family)
+static void ss_init_inany(struct sockaddr_storage *sa, sa_family_t family)
 {
 	memset(sa, 0, sizeof(*sa));
-	sa->family = family;
-	if (sa->family == AF_INET6)
-		sa->v6.sin6_addr = in6addr_any;
+	sa->ss_family = family;
+	if (sa->ss_family == AF_INET6)
+		((struct sockaddr_in6 *)sa)->sin6_addr = in6addr_any;
 	else
-		sa->v4.sin_addr.s_addr = INADDR_ANY;
+		((struct sockaddr_in *)sa)->sin_addr.s_addr = INADDR_ANY;
 }
 
 static int read_int_sysctl(const char *sysctl)
@@ -228,7 +224,7 @@ static void check_data(int type, sa_family_t family, const struct cmd *cmd,
 		       int cli_fd)
 {
 	struct data_check expected = {}, result;
-	union sa46 cli_sa;
+	struct sockaddr_storage cli_sa;
 	socklen_t addrlen;
 	int err;
 
@@ -251,26 +247,32 @@ static void check_data(int type, sa_family_t family, const struct cmd *cmd,
 	}
 
 	if (family == AF_INET6) {
+		struct sockaddr_in6 *srv_v6 = (struct sockaddr_in6 *)&srv_sa;
+		struct sockaddr_in6 *cli_v6 = (struct sockaddr_in6 *)&cli_sa;
+
 		expected.eth_protocol = htons(ETH_P_IPV6);
-		expected.bind_inany = !srv_sa.v6.sin6_addr.s6_addr32[3] &&
-			!srv_sa.v6.sin6_addr.s6_addr32[2] &&
-			!srv_sa.v6.sin6_addr.s6_addr32[1] &&
-			!srv_sa.v6.sin6_addr.s6_addr32[0];
+		expected.bind_inany = !srv_v6->sin6_addr.s6_addr32[3] &&
+			!srv_v6->sin6_addr.s6_addr32[2] &&
+			!srv_v6->sin6_addr.s6_addr32[1] &&
+			!srv_v6->sin6_addr.s6_addr32[0];
 
-		memcpy(&expected.skb_addrs[0], cli_sa.v6.sin6_addr.s6_addr32,
-		       sizeof(cli_sa.v6.sin6_addr));
+		memcpy(&expected.skb_addrs[0], cli_v6->sin6_addr.s6_addr32,
+		       sizeof(cli_v6->sin6_addr));
 		memcpy(&expected.skb_addrs[4], &in6addr_loopback,
 		       sizeof(in6addr_loopback));
-		expected.skb_ports[0] = cli_sa.v6.sin6_port;
-		expected.skb_ports[1] = srv_sa.v6.sin6_port;
+		expected.skb_ports[0] = cli_v6->sin6_port;
+		expected.skb_ports[1] = srv_v6->sin6_port;
 	} else {
+		struct sockaddr_in *srv_v4 = (struct sockaddr_in *)&srv_sa;
+		struct sockaddr_in *cli_v4 = (struct sockaddr_in *)&cli_sa;
+
 		expected.eth_protocol = htons(ETH_P_IP);
-		expected.bind_inany = !srv_sa.v4.sin_addr.s_addr;
+		expected.bind_inany = !srv_v4->sin_addr.s_addr;
 
-		expected.skb_addrs[0] = cli_sa.v4.sin_addr.s_addr;
+		expected.skb_addrs[0] = cli_v4->sin_addr.s_addr;
 		expected.skb_addrs[1] = htonl(INADDR_LOOPBACK);
-		expected.skb_ports[0] = cli_sa.v4.sin_port;
-		expected.skb_ports[1] = srv_sa.v4.sin_port;
+		expected.skb_ports[0] = cli_v4->sin_port;
+		expected.skb_ports[1] = srv_v4->sin_port;
 	}
 
 	if (memcmp(&result, &expected, offsetof(struct data_check,
@@ -364,16 +366,15 @@ static void check_results(void)
 static int send_data(int type, sa_family_t family, void *data, size_t len,
 		     enum result expected)
 {
-	union sa46 cli_sa;
+	struct sockaddr_storage cli_sa;
 	int fd, err;
 
 	fd = socket(family, type, 0);
 	RET_ERR(fd == -1, "socket()", "fd:%d errno:%d\n", fd, errno);
 
-	sa46_init_loopback(&cli_sa, family);
+	ss_init_loopback(&cli_sa, family);
 	err = bind(fd, (struct sockaddr *)&cli_sa, sizeof(cli_sa));
 	RET_ERR(fd == -1, "bind(cli_sa)", "err:%d errno:%d\n", err, errno);
-
 	err = sendto(fd, data, len, MSG_FASTOPEN, (struct sockaddr *)&srv_sa,
 		     sizeof(srv_sa));
 	RET_ERR(err != len && expected >= PASS,
@@ -589,9 +590,9 @@ static void prepare_sk_fds(int type, sa_family_t family, bool inany)
 	socklen_t addrlen;
 
 	if (inany)
-		sa46_init_inany(&srv_sa, family);
+		ss_init_inany(&srv_sa, family);
 	else
-		sa46_init_loopback(&srv_sa, family);
+		ss_init_loopback(&srv_sa, family);
 	addrlen = sizeof(srv_sa);
 
 	/*