socket: Remove OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED, add osmo_sock_init2_multiaddr2()

The OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED flag was added recently to enable
use of ASCONF in osmo_sock_inti2_multiaddr. Since we didn't release yet,
we are still in time to get rid of this flag.

It turns out that we'll want to add more features which must be set
before SCTP INIT (connect()) time, like setsockopt SCTP_INITMSG, which
in turn contains a struct with several parameters.
Hence, adding flags for all those makes no sense.
Instead, add a new API which allows passing an extensible struct which
allows much more fine-grained setup from the caller.

The new struct "pars" parameter is non-const on purpose, in order to be
able to extend the struct in the future if we wish to get/obtain some
data from the socket.

Related: SYS#6501
Related: SYS#6558
Change-Id: I1f6fd09a79b0a2bd794e5669d933be25bbf1eeaa

4 files changed, 79 insertions, 13 deletions

diff --git a/TODO-RELEASE b/TODO-RELEASE
index f78104e8..2d9e32ee 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -17,4 +17,5 @@ libosmogsm	ADD	new osmo_sub_auth_data2 / osmo_auth_gen_vec2 / osmo_auth_gen_vec_
 libosmogsm	MODIFY	osmo_auth_impl callback function signature change. No known external users
 libosmogsm	ADD	osmo_auth_c2
 libosmogsm	ADD	OSMO_AUTH_ALG_TUAK
-libosmogsm	ADD	new API msgb_tv32_push()
\ No newline at end of file
+libosmogsm	ADD	new API msgb_tv32_push()
+libosmocore	ADD	osmo_sock_init2_multiaddr2()
\ No newline at end of file
diff --git a/include/osmocom/core/socket.h b/include/osmocom/core/socket.h
index c68bb6f0..ba986f84 100644
--- a/include/osmocom/core/socket.h
+++ b/include/osmocom/core/socket.h
@@ -14,6 +14,8 @@
 
 #include <arpa/inet.h>
 
+#include <osmocom/core/defs.h>
+
 /*! maximum length of a socket name ("r=1.2.3.4:123<->l=5.6.7.8:987") */
 #define OSMO_SOCK_NAME_MAXLEN (2 + INET6_ADDRSTRLEN + 1 + 5 + 3 + 2 + INET6_ADDRSTRLEN + 1 + 5 + 1)
 
@@ -94,8 +96,6 @@ char *osmo_sockaddr_to_str_c(void *ctx, const struct osmo_sockaddr *sockaddr);
 #define OSMO_SOCK_F_NO_MCAST_ALL  (1 << 4)
 /*! use SO_REUSEADDR on UDP ports (required for multicast) */
 #define OSMO_SOCK_F_UDP_REUSEADDR (1 << 5)
-/*! use SCTP_AUTH_SUPPORTED + SCTP_ASCONF_SUPPORTED on SCTP socket (required for ASCONF / Peer Primary Address feature) */
-#define OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED (1 << 6)
 
 /*! use OSMO_SOCK_F_DSCP(x) to set IP DSCP 'x' for packets transmitted on the socket */
 #define OSMO_SOCK_F_DSCP(x)	(((x)&0x3f) << 24)
@@ -116,9 +116,32 @@ int osmo_sock_init2(uint16_t family, uint16_t type, uint8_t proto,
 		   const char *local_host, uint16_t local_port,
 		   const char *remote_host, uint16_t remote_port, unsigned int flags);
 
+struct osmo_sock_init2_multiaddr_pars {
+	union {
+		struct {
+			uint8_t version; /* set to 0 */
+			struct {
+				bool set;
+				bool abort_on_failure;
+				uint32_t value;
+			} sockopt_auth_supported;
+			struct {
+				bool set;
+				bool abort_on_failure;
+				uint32_t value;
+			} sockopt_asconf_supported;
+		} sctp;
+	};
+};
 int osmo_sock_init2_multiaddr(uint16_t family, uint16_t type, uint8_t proto,
 		   const char **local_hosts, size_t local_hosts_cnt, uint16_t local_port,
-		   const char **remote_hosts, size_t remote_hosts_cnt, uint16_t remote_port, unsigned int flags);
+		   const char **remote_hosts, size_t remote_hosts_cnt, uint16_t remote_port, unsigned int flags)
+		   OSMO_DEPRECATED_OUTSIDE("Use osmo_sock_init2_multiaddr2() instead");
+int osmo_sock_init2_multiaddr2(uint16_t family, uint16_t type, uint8_t proto,
+		   const char **local_hosts, size_t local_hosts_cnt, uint16_t local_port,
+		   const char **remote_hosts, size_t remote_hosts_cnt, uint16_t remote_port,
+		   unsigned int flags, struct osmo_sock_init2_multiaddr_pars *pars);
+
 
 int osmo_sock_init_osa(uint16_t type, uint8_t proto,
 		    const struct osmo_sockaddr *local,
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index 99be86cb..c0e164b7 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -419,6 +419,7 @@ osmo_sock_get_remote_ip_port;
 osmo_sock_init;
 osmo_sock_init2;
 osmo_sock_init2_multiaddr;
+osmo_sock_init2_multiaddr2;
 osmo_sock_init2_ofd;
 osmo_sock_init_ofd;
 osmo_sock_init_osa;
diff --git a/src/core/socket.c b/src/core/socket.c
index 3c2ba501..65da2032 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -696,33 +696,33 @@ static int addrinfo_to_sockaddr(uint16_t family, const struct addrinfo **result,
 	return 0;
 }
 
-static int setsockopt_sctp_auth_supported(int fd)
+static int setsockopt_sctp_auth_supported(int fd, uint32_t val)
 {
 #ifdef SCTP_AUTH_SUPPORTED
 	struct sctp_assoc_value assoc_val = {
 		.assoc_id = SCTP_FUTURE_ASSOC,
-		.assoc_value = 1,
+		.assoc_value = val,
 	};
 	return setsockopt(fd, IPPROTO_SCTP, SCTP_AUTH_SUPPORTED, &assoc_val, sizeof(assoc_val));
 #else
 #pragma message "setsockopt(SCTP_AUTH_SUPPORTED) not supported! some SCTP features may not be available!"
 	LOGP(DLGLOBAL, LOGL_NOTICE, "Built without support for setsockopt(SCTP_AUTH_SUPPORTED), skipping\n");
-	return 0;
+	return -ENOTSUP;
 #endif
 }
 
-static int setsockopt_sctp_asconf_supported(int fd)
+static int setsockopt_sctp_asconf_supported(int fd, uint32_t val)
 {
 #ifdef SCTP_ASCONF_SUPPORTED
 	struct sctp_assoc_value assoc_val = {
 		.assoc_id = SCTP_FUTURE_ASSOC,
-		.assoc_value = 1,
+		.assoc_value = val,
 	};
 	return setsockopt(fd, IPPROTO_SCTP, SCTP_ASCONF_SUPPORTED, &assoc_val, sizeof(assoc_val));
 #else
 #pragma message "setsockopt(SCTP_ASCONF_SUPPORTED) not supported! some SCTP features may not be available!"
 	LOGP(DLGLOBAL, LOGL_NOTICE, "Built without support for setsockopt(SCTP_ASCONF_SUPPORTED), skipping\n");
-	return 0;
+	return -ENOTSUP;
 #endif
 }
 
@@ -750,6 +750,38 @@ int osmo_sock_init2_multiaddr(uint16_t family, uint16_t type, uint8_t proto,
 		   const char **local_hosts, size_t local_hosts_cnt, uint16_t local_port,
 		   const char **remote_hosts, size_t remote_hosts_cnt, uint16_t remote_port,
 		   unsigned int flags)
+{
+	return osmo_sock_init2_multiaddr2(family, type, proto, local_hosts, local_hosts_cnt, local_port,
+					      remote_hosts, remote_hosts_cnt, remote_port, flags, NULL);
+}
+
+/*! Initialize a socket (including bind and/or connect) with multiple local or remote addresses.
+ *  \param[in] family Address Family like AF_INET, AF_INET6, AF_UNSPEC
+ *  \param[in] type Socket type like SOCK_DGRAM, SOCK_STREAM
+ *  \param[in] proto Protocol like IPPROTO_TCP, IPPROTO_UDP
+ *  \param[in] local_hosts array of char pointers (strings), each containing local host name or IP address in string form
+ *  \param[in] local_hosts_cnt length of local_hosts (in items)
+ *  \param[in] local_port local port number in host byte order
+ *  \param[in] remote_host array of char pointers (strings), each containing remote host name or IP address in string form
+ *  \param[in] remote_hosts_cnt length of remote_hosts (in items)
+ *  \param[in] remote_port remote port number in host byte order
+ *  \param[in] flags flags like \ref OSMO_SOCK_F_CONNECT
+ *  \param[in] pars Extra parameters for multi-address specific protocols, such as SCTP. Can be NULL.
+ *  \returns socket file descriptor on success; negative on error
+ *
+ * This function is similar to \ref osmo_sock_init2(), but can be passed an
+ * array of local or remote addresses for protocols supporting multiple
+ * addresses per socket, like SCTP (currently only one supported). This function
+ * should not be used by protocols not supporting this kind of features, but
+ * rather \ref osmo_sock_init2() should be used instead.
+ * See \ref osmo_sock_init2() for more information on flags and general behavior.
+ *
+ * pars: If "pars" parameter is passed to the function, sctp.version shall be set to 0.
+ */
+int osmo_sock_init2_multiaddr2(uint16_t family, uint16_t type, uint8_t proto,
+		   const char **local_hosts, size_t local_hosts_cnt, uint16_t local_port,
+		   const char **remote_hosts, size_t remote_hosts_cnt, uint16_t remote_port,
+		   unsigned int flags, struct osmo_sock_init2_multiaddr_pars *pars)
 
 {
 	struct addrinfo *res_loc[OSMO_SOCK_MAX_ADDRS], *res_rem[OSMO_SOCK_MAX_ADDRS];
@@ -769,6 +801,9 @@ int osmo_sock_init2_multiaddr(uint16_t family, uint16_t type, uint8_t proto,
 	if (proto != IPPROTO_SCTP)
 		return -ENOTSUP;
 
+	if (pars && pars->sctp.version != 0)
+		return -EINVAL;
+
 	if ((flags & (OSMO_SOCK_F_BIND | OSMO_SOCK_F_CONNECT)) == 0) {
 		LOGP(DLGLOBAL, LOGL_ERROR, "invalid: you have to specify either "
 			"BIND or CONNECT flags\n");
@@ -841,26 +876,32 @@ int osmo_sock_init2_multiaddr(uint16_t family, uint16_t type, uint8_t proto,
 			goto ret_close;
 		}
 
-		if (flags & OSMO_SOCK_F_SCTP_ASCONF_SUPPORTED) {
+		if (pars && pars->sctp.sockopt_auth_supported.set) {
 			/* RFC 5061 4.2.7: ASCONF also requires AUTH feature. */
-			rc = setsockopt_sctp_auth_supported(sfd);
+			rc = setsockopt_sctp_auth_supported(sfd, pars->sctp.sockopt_auth_supported.value);
 			if (rc < 0) {
 				int err = errno;
 				multiaddr_snprintf(strbuf, sizeof(strbuf), local_hosts, local_hosts_cnt);
 				LOGP(DLGLOBAL, LOGL_ERROR,
 				     "cannot setsockopt(SCTP_AUTH_SUPPORTED) socket: %s:%u: %s\n",
 				     strbuf, local_port, strerror(err));
+				if (pars->sctp.sockopt_auth_supported.abort_on_failure)
+					goto ret_close;
 				/* do not fail, some features such as Peer Primary Address won't be available
 				 * unless configured system-wide through sysctl */
 			}
+		}
 
-			rc = setsockopt_sctp_asconf_supported(sfd);
+		if (pars && pars->sctp.sockopt_asconf_supported.set) {
+			rc = setsockopt_sctp_asconf_supported(sfd, pars->sctp.sockopt_asconf_supported.value);
 			if (rc < 0) {
 				int err = errno;
 				multiaddr_snprintf(strbuf, sizeof(strbuf), local_hosts, local_hosts_cnt);
 				LOGP(DLGLOBAL, LOGL_ERROR,
 				     "cannot setsockopt(SCTP_ASCONF_SUPPORTED) socket: %s:%u: %s\n",
 				     strbuf, local_port, strerror(err));
+				if (pars->sctp.sockopt_asconf_supported.abort_on_failure)
+					goto ret_close;
 				/* do not fail, some features such as Peer Primary Address won't be available
 				 * unless configured system-wide through sysctl */
 			}