osmo-bsc: cleanup osmo_bsc_sigtran_init()

1 files changed, 76 insertions, 39 deletions

diff --git a/openbsc/src/osmo-bsc/osmo_bsc_sigtran.c b/openbsc/src/osmo-bsc/osmo_bsc_sigtran.c
index de9416df8..2007689d8 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_sigtran.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_sigtran.c
@@ -411,73 +411,92 @@ static void osmo_bsc_sigtran_reset_cb(const void *priv)
 	osmo_bsc_sigtran_tx_reset(msc);
 }
 
+/* Default point-code to be used as local address (BSC) */
+#define BSC_DEFAULT_PC "0.23.3"
+
+/* Default point-code to be used as remote address (MSC) */
+#define MSC_DEFAULT_PC "0.23.1"
+
 /* Initalize osmo sigtran backhaul */
 int osmo_bsc_sigtran_init(struct llist_head *mscs)
 {
-	/* FIXME: Remove hardcoded IP-Addresses */
+	bool free_attempt_used = false;
+	bool fail_on_next_invalid_cfg = false;
+
 	struct bsc_msc_data *msc;
-	char msc_name[256];
-	uint32_t bsc_default_pc = CS7_POINTCODE_DEFAULT_OFFSET;
-	uint8_t cs7_default_inst = 0;
-
-	/* FIXME: The way this code derives the default parameters is not safe when
-	 * mixing proper configuration with incomplete configuration. When multiple
-	 * MSCs are connected, the autogenerated pointcodes may colide with the
-	 * ones that are properly set. However, this is a very unlikely situation.
-	 * in most cases it will be exactly one MSC<->BSC connection and either no
-	 * configuration done by the user or the user knows how to properly set
-	 * up the configuration */
+	char msc_name[32];
+	uint32_t default_pc;
 
 	OSMO_ASSERT(mscs);
 	msc_list = mscs;
-	conn_id_counter = 0;
 
 	llist_for_each_entry(msc, msc_list, entry) {
 		snprintf(msc_name, sizeof(msc_name), "msc-%u", msc->nr);
-		LOGP(DMSC, LOGL_NOTICE, "Initializing SCCP connection to MSC %s (%s)\n",
-		     osmo_sccp_addr_dump(&msc->a.msc_addr), msc_name);
+		LOGP(DMSC, LOGL_NOTICE, "Initializing SCCP connection to MSC %s\n", msc_name);
 
-		/* Check if the VTY could determine a valid CS7 instance */
+		/* Check if the VTY could determine a valid CS7 instance,
+		 * use safe default in case none is set */
 		if (msc->a.cs7_instance_valid == false) {
-			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: Unable to detect CS7 instance, assuming instance ID: %u\n",
-			     cs7_default_inst);
-			msc->a.cs7_instance = cs7_default_inst;
+			msc->a.cs7_instance = 0;
+			if (fail_on_next_invalid_cfg)
+				goto fail_auto_cofiguration;
+			free_attempt_used = true;
+		}
+		LOGP(DMSC, LOGL_NOTICE, "CS7 Instance identifier, A-Interface: %u\n", msc->a.cs7_instance);
+
+		/* Pre-Check if there is an ss7 instance present */
+		if (osmo_ss7_instance_find(msc->a.cs7_instance) == NULL) {
+			if (fail_on_next_invalid_cfg)
+				goto fail_auto_cofiguration;
+			free_attempt_used = true;
 		}
-		cs7_default_inst++;
 
 		/* SS7 Protocol stack */
+		default_pc = osmo_ss7_pointcode_parse(NULL, BSC_DEFAULT_PC);
 		msc->a.sccp =
-		    osmo_sccp_simple_client_on_ss7_id(msc, msc->a.cs7_instance, msc_name, bsc_default_pc,
-						      OSMO_SS7_ASP_PROT_M3UA, 0, NULL, M3UA_PORT, "127.0.0.1");
+		    osmo_sccp_simple_client_on_ss7_id(msc, msc->a.cs7_instance, msc_name, default_pc,
+						      OSMO_SS7_ASP_PROT_M3UA, 0, NULL, 0, NULL);
 		if (!msc->a.sccp)
 			return -EINVAL;
-		bsc_default_pc++;
 
-		/* Check if the sccp-address fullfill minimum requirements (SSN+PC is present,
+		/* 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)) {
-			/* In case a valid address is not set, derive the address from the SCCP
-			 * instance that has just been created */
+			if (fail_on_next_invalid_cfg)
+				goto fail_auto_cofiguration;
+			free_attempt_used = true;
+
 			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: invalid or missing local SCCP address (a.bsc_addr=%s)\n",
-			     osmo_sccp_addr_dump(&msc->a.bsc_addr));
+			     "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));
 			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 SCCP address (a.bsc_addr=%s)\n",
-			     osmo_sccp_addr_dump(&msc->a.bsc_addr));
+			     "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",
+			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.bsc_addr));
 		}
+
 		if (!osmo_sccp_check_addr(&msc->a.msc_addr, OSMO_SCCP_ADDR_T_SSN | OSMO_SCCP_ADDR_T_PC)) {
-			/* In case a valid address is not set, use the SCCP instance to query a local
-			 * address and subtract one from the pointcode */
-			LOGP(DMSC, LOGL_ERROR,
-			     "A-interface: invalid or missing remote SCCP address for the MSC (a.msc_addr=%s)\n",
-			     osmo_sccp_addr_dump(&msc->a.msc_addr));
+			if (fail_on_next_invalid_cfg)
+				goto fail_auto_cofiguration;
+			free_attempt_used = true;
+
+			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 -= 1;
+			msc->a.msc_addr.pc = osmo_ss7_pointcode_parse(NULL, MSC_DEFAULT_PC);
 			LOGP(DMSC, LOGL_NOTICE,
-			     "A-interface: using automatically generated SCCP address (a.msc_addr=%s)\n",
-			     osmo_sccp_addr_dump(&msc->a.msc_addr));
+			     "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",
+			     osmo_sccp_addr_name(osmo_ss7_instance_find(msc->a.cs7_instance), &msc->a.msc_addr));
 		}
 
 		/* Bind SCCP user */
@@ -489,7 +508,25 @@ int osmo_bsc_sigtran_init(struct llist_head *mscs)
 		msc->a.reset = a_reset_alloc(msc, msc_name, osmo_bsc_sigtran_reset_cb, msc);
 		if (!msc->a.reset)
 			return -EINVAL;
+
+		/* If we have detected that the SS7 configuration of the MSC we have just initalized
+		 * was incomplete or completely missing, we can not tolerate another incomplete
+		 * configuration. The reson for this is that we do only specify exactly one default
+		 * pointcode pair. We also specify localhost as default IP-Address. If we have wanted
+		 * to support multiple MSCs with automatic configuration we would be forced to invent
+		 * a complex ruleset how to allocate the pointcodes and respective IP-Addresses.
+		 * Furthermore, the situation where a single BSC is connected to multiple MSCs
+		 * is a very rare situation anyway. In this case we expect the user to experienced
+		 * enough to create a valid SS7/CS7 VTY configuration that does not lack any
+		 * components */
+		if (free_attempt_used)
+			fail_on_next_invalid_cfg = true;
 	}
 
 	return 0;
+
+fail_auto_cofiguration:
+	LOGP(DMSC, LOGL_ERROR,
+	     "A-interface: More than one invalid/inclomplete configuration detected, unable to revover - check config file!\n");
+	return -EINVAL;
 }