osmo-bsc: SCCP addrs: default only if unset, reject invalid

So far, if the user entered an invalid SCCP address in the config, the
osmo_bsc_sigtran_init() code simply replaced that with the default, i.e.
running with a completely different address than the user may intend.

Use the default SCCP addresses only when they are unset by the user.

Default MSC addr: set directly, do not detour via cs7 instance PC. The default
MSC SCCP addr is just a point code + SSN, deriving it from the cs7 instance
first is a confusing step. Just set the PC and SSN, and done.

Using default addresses does not constitute an "auto configuration": if we set
up a cs7 instance automatically, we do not want to have to create a second one
automatically, to prevent "auto-confusion", and want to bail instead. But for
each MSC on its own, using default SCCP addresses makes sense and is orthogonal
to automatic cs7 instance creation. Hence drop the auto config semantics from
the default SCCP address parts.

Always validate the SCCP addresses we will end up using, and bail immediately
if they are erratic. i.e. don't overwrite a non-empty invalid SCCP address with
defaults, but straight bail.

Beneficial side effects:
- Fix some grammar ultra confusion in log messages.
- Add context: log the MSC number the logging refers to.
- Drop code dup: since we're always logging the used SCCP addresses, might as
  well log those once, unconditionally, in the end.

Change-Id: Iadbc2e9740457e1b389b7e7ad9c94274e7d8cb11

1 files changed, 25 insertions, 32 deletions

diff --git a/src/osmo-bsc/osmo_bsc_sigtran.c b/src/osmo-bsc/osmo_bsc_sigtran.c
index 2ba777ed9..253f1e866 100644
--- a/src/osmo-bsc/osmo_bsc_sigtran.c
+++ b/src/osmo-bsc/osmo_bsc_sigtran.c
@@ -509,46 +509,39 @@ int osmo_bsc_sigtran_init(struct llist_head *mscs)
 		if (!msc->a.sccp)
 			return -EINVAL;
 
-		/* Check if the sccp-address fullfills minimum requirements (SSN+PC is present,
-		 * automatically recover addresses if the addresses are not set up properly) */
-		if (!osmo_sccp_check_addr(&msc->a.bsc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
-			if (fail_on_next_invalid_cfg)
-				goto fail_auto_cofiguration;
-			free_attempt_used = true;
-
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: invalid or missing local (BSC) SCCP address (a.bsc_addr=%s)\n",
-			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
+		/* If unset, use default local SCCP address */
+		if (!msc->a.bsc_addr.presence)
 			osmo_sccp_local_addr_by_instance(&msc->a.bsc_addr, msc->a.sccp, SCCP_SSN_BSSAP);
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: using automatically generated local (BSC) SCCP address (a.bsc_addr=%s)\n",
-			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
-		} else {
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: using local (BSC) automatically SCCP address (a.msc_addr=%s)\n",
+
+		if (!osmo_sccp_check_addr(&msc->a.bsc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
+			LOGP(DMSC, LOGL_ERROR,
+			     "(%s) A-interface: invalid local (BSC) SCCP address: %s\n",
+			     msc_name,
 			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
+			return -EINVAL;
 		}
 
-		if (!osmo_sccp_check_addr(&msc->a.msc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
-			if (fail_on_next_invalid_cfg)
-				goto fail_auto_cofiguration;
-			free_attempt_used = true;
+		/* If unset, use default SCCP address for the MSC */
+		if (!msc->a.msc_addr.presence)
+			osmo_sccp_make_addr_pc_ssn(&msc->a.msc_addr,
+						   osmo_ss7_pointcode_parse(NULL, MSC_DEFAULT_PC),
+						   SCCP_SSN_BSSAP);
 
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: invalid or missing remote (MSC) SCCP address for the MSC (a.msc_addr=%s)\n",
-			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
-			osmo_sccp_local_addr_by_instance(&msc->a.msc_addr, msc->a.sccp, SCCP_SSN_BSSAP);
-			msc->a.msc_addr.pc = osmo_ss7_pointcode_parse(NULL, MSC_DEFAULT_PC);
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: using automatically generated remote (MSC) SCCP address (a.msc_addr=%s)\n",
-			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
-			free_attempt_used = true;
-		} else {
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: using remote (MSC) automatically SCCP address (a.msc_addr=%s)\n",
+		if (!osmo_sccp_check_addr(&msc->a.msc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
+			LOGP(DMSC, LOGL_ERROR,
+			     "(%s) A-interface: invalid remote (MSC) SCCP address: %s\n",
+			     msc_name,
 			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
+			return -EINVAL;
 		}
 
+		LOGP(DMSC, LOGL_NOTICE, "(%s) A-interface: local (BSC) SCCP address: %s\n",
+		     msc_name,
+		     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
+		LOGP(DMSC, LOGL_NOTICE, "(%s) A-interface: remote (MSC) SCCP address: %s\n",
+		     msc_name,
+		     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
+
 		/* Bind SCCP user */
 		msc->a.sccp_user = osmo_sccp_user_bind(msc->a.sccp, msc_name, sccp_sap_up, msc->a.bsc_addr.ssn);
 		if (!msc->a.sccp_user)