Add osmo_sock_get_name_multiaddr_buf()

It's similar to osmo_sock_get_name_buf() but supports multi-homed SCTP sockets
bound to several addresses.

Related: OS#5581
Change-Id: If76595ebd1cf26ba904887a36c4cc14a1b5c4521

include/osmocom/core/socket.h

@@ -105,6 +105,7 @@ int osmo_sock_unix_init_ofd(struct osmo_fd *ofd, uint16_t type, uint8_t proto,
 			    const char *socket_path, unsigned int flags);
 
 char *osmo_sock_get_name(const void *ctx, int fd);
+int osmo_sock_get_name_multiaddr_buf(char *buf, size_t buf_len, int fd, bool print_ports);
 const char *osmo_sock_get_name2(int fd);
 char *osmo_sock_get_name2_c(const void *ctx, int fd);
 int osmo_sock_get_name_buf(char *str, size_t str_len, int fd);

src/socket.c

@@ -898,6 +898,95 @@ ret_freeaddrinfo_loc:
 	}
 	return rc;
 }
+
+static int sctp_multiaddr_print_ctx_helper(struct osmo_strbuf *sb, int fd, bool local)
+{
+	struct sockaddr *addrs = NULL;
+
+	/* 2nd parameter 0 for sctp_get?addrs() means "disregard any particular association" */
+	int rc, addr_count = local ? sctp_getladdrs(fd, 0, &addrs) : sctp_getpaddrs(fd, 0, &addrs);
+
+	if (addr_count == -1) { /* We expect this to fail if corresponding side of the socket is not connected */
+		LOGP(DLGLOBAL, LOGL_DEBUG, "Error occurred while calling sctp_get%caddrs()\n", local ? 'l' : 'p');
+		return -EFAULT;
+	}
+
+	if (addr_count == 0) {
+		LOGP(DLGLOBAL, LOGL_DEBUG, "Calling sctp_get%caddrs() on unbound socket\n", local ? 'l' : 'p');
+		return -ENOTCONN;
+	}
+
+	if (addr_count > OSMO_SOCK_MAX_ADDRS) {
+		LOGP(DLGLOBAL, LOGL_DEBUG, "Dropping addresses exceeding limit: %u > %u\n", addr_count, OSMO_SOCK_MAX_ADDRS);
+		addr_count = OSMO_SOCK_MAX_ADDRS;
+	}
+
+	rc = multiaddr_strbuf(sb, NULL, 0, &addrs, addr_count);
+	local ? sctp_freeladdrs(addrs) : sctp_freepaddrs(addrs);
+
+	return rc;
+}
+
+/*! Get address/port information on socket in provided string buffer, like "r=1.2.3.4:5<->l=(6.7.8.9|4.3.2.1):10".
+ *  \param[out] buff  Destination string buffer.
+ *  \param[in] buf_len  sizeof(buff).
+ *  \param[in] fd  File descriptor of socket.
+ *  \param[in] print_ports Flag indicating whether ports should be printed in addition to IP addresses as well.
+ *  \return String length as returned by snprintf(), or negative on error.
+ */
+int osmo_sock_get_name_multiaddr_buf(char *buff, size_t buf_len, int fd, bool print_ports)
+{
+	int rc;
+	char portbuf_l[6], portbuf_r[6],
+		hostbuf_l[OSMO_SOCK_MAX_ADDRS * OSMO_SOCK_NAME_MAXLEN] = { 0 },
+		hostbuf_r[OSMO_SOCK_MAX_ADDRS * OSMO_SOCK_NAME_MAXLEN] = { 0 };
+	struct osmo_strbuf sb = { .buf = buff, .len = buf_len };
+	struct osmo_strbuf sb_l = { .buf = hostbuf_l, .len = sizeof(hostbuf_l) };
+	struct osmo_strbuf sb_r = { .buf = hostbuf_r, .len = sizeof(hostbuf_r) };
+
+	/* get local */
+	rc = sctp_multiaddr_print_ctx_helper(&sb_l, fd, true);
+	if (rc < 0) {
+		OSMO_STRBUF_PRINTF(sb, "<error-in-sctp_getladdrs>");
+		return rc;
+	}
+
+	if (print_ports) {
+		/* according to https://datatracker.ietf.org/doc/html/rfc4960 multi-homed SCTP has to use the same port number */
+		rc = osmo_sock_get_local_ip_port(fd, portbuf_l, sizeof(portbuf_l));
+		if (rc < 0) {
+			OSMO_STRBUF_PRINTF(sb, "<error-in-osmo_sock_get_local_ip_port>");
+			return rc;
+		}
+	}
+
+	/* get remote */
+	rc = sctp_multiaddr_print_ctx_helper(&sb_r, fd, false);
+	if (rc < 0) {
+		if (print_ports)
+			OSMO_STRBUF_PRINTF(sb, "r=NULL<->l=%s:%s", hostbuf_l, portbuf_l);
+		else
+			OSMO_STRBUF_PRINTF(sb, "r=NULL<->l=%s", hostbuf_l);
+		return 0;
+	}
+
+	/* assemble */
+	if (print_ports) {
+		rc = osmo_sock_get_remote_ip_port(fd, portbuf_r, sizeof(portbuf_r));
+		if (rc < 0) {
+			OSMO_STRBUF_PRINTF(sb, "<error-in-osmo_sock_get_local_ip_port>");
+			return rc;
+		}
+	}
+
+	if (print_ports)
+		OSMO_STRBUF_PRINTF(sb, "r=%s:%s<->l=%s:%s", hostbuf_r, portbuf_r, hostbuf_l, portbuf_l);
+	else
+		OSMO_STRBUF_PRINTF(sb, "r=%s<->l=%s", hostbuf_r, hostbuf_l);
+
+	return 0;
+}
+
 #endif /* HAVE_LIBSCTP */
 
 /*! Initialize a socket (including bind/connect)

tests/socket/socket_sctp_test.c

@@ -60,6 +60,7 @@ static int test_sockinit2_multiaddr(const char **addrv4_loc, const char **addrv6
 	int fd, rc;
 	int listen_fd_v4, listen_fd_v6;
 	int listen_port_v4, listen_port_v6;
+	char buf[OSMO_SOCK_NAME_MAXLEN * OSMO_SOCK_MAX_ADDRS];
 
 	printf("Checking osmo_sock_init2_multiaddr() with bind to a random local SCTP IPv4 port\n");
 
@@ -129,13 +130,16 @@ static int test_sockinit2_multiaddr(const char **addrv4_loc, const char **addrv6
 				       OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
 	OSMO_ASSERT(fd >= 0);
 
-	printf("Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6\n");
+	printf("\n[%zu] Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6:\n", addrv6_size);
 	fd = osmo_sock_init2_multiaddr(AF_UNSPEC, SOCK_STREAM, IPPROTO_SCTP,
 				       addrv6_rem, addrv6_size, 0,
 				       addrv6_rem, addrv6_size, listen_port_v6,
 				       OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
 	OSMO_ASSERT(fd >= 0);
 
+	rc = osmo_sock_get_name_multiaddr_buf(buf, OSMO_SOCK_NAME_MAXLEN * OSMO_SOCK_MAX_ADDRS, fd, false);
+	printf("Bound on %s [%d]\n", buf, rc);
+
 	close(listen_fd_v4);
 	close(listen_fd_v6);
 	printf("Done\n");

tests/socket/socket_sctp_test.ok

@@ -6,7 +6,9 @@ Checking osmo_sock_init2_multiaddr() for combined BIND + CONNECT
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) must fail on mixed IPv4 & IPv6
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) must fail on mixed IPv6 & IPv4
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv4
-Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6
+
+[1] Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6:
+Bound on r=NULL<->l=::1 [0]
 Done
 Checking osmo_sock_init2_multiaddr() with bind to a random local SCTP IPv4 port
 Checking osmo_sock_init2_multiaddr() with bind to a random local SCTP IPv6 port
@@ -16,7 +18,9 @@ Checking osmo_sock_init2_multiaddr() for combined BIND + CONNECT
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) must fail on mixed IPv4 & IPv6
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) must fail on mixed IPv6 & IPv4
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv4
-Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6
+
+[1] Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND + CONNECT on IPv6:
+Bound on r=::1<->l=::1 [0]
 Done
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND on AF_INET IPv4+v6 fails
 Checking osmo_sock_init2_multiaddr(AF_UNSPEC) BIND on AF_INET6 IPv4+v6 fails