abis.c: Loop over list of BSCs until connection succeeds

Do not exit if all BSCs in the list fail to connect, keep trying
forever. This commit still doesn't change the logic after BTS has
successfully connected to a BSC. In that situation, if the link goes
down, BTS will exit in order to reset all state and let the user/system
restart it.

Related: SYS#4971
Change-Id: I67bba3b7e2d9d62b98a59a74987ae55206a3ec51

1 files changed, 25 insertions, 6 deletions

diff --git a/src/common/abis.c b/src/common/abis.c
index c230a4b5..31a3505b 100644
--- a/src/common/abis.c
+++ b/src/common/abis.c
@@ -61,9 +61,11 @@ static struct e1inp_line_ops line_ops;
 static struct ipaccess_unit bts_dev_info;
 
 #define S(x) (1 << (x))
+#define	OML_RETRY_TIMER	5
 
 enum abis_link_fsm_state {
-	ABIS_LINK_ST_CONNECTING, /* OML link has not yet been established */
+	ABIS_LINK_ST_WAIT_RECONNECT, /* OML link has not yet been established */
+	ABIS_LINK_ST_CONNECTING, /* OML link in process of been established */
 	ABIS_LINK_ST_CONNECTED, /* OML link is established, RSL links may be established or not */
 	ABIS_LINK_ST_FAILED, /* There used to be an active OML connection but it became broken */
 };
@@ -128,12 +130,10 @@ static int pick_next_bsc(struct osmo_fsm_inst *fi)
 
 	last = (struct bsc_oml_host *)llist_last_entry(&bts->bsc_oml_hosts, struct bsc_oml_host, list);
 
-	if (!priv->current_bsc) /* Pick first one: */
+	if (!priv->current_bsc || priv->current_bsc == last) /* Pick first one (wrap around): */
 		priv->current_bsc = (struct bsc_oml_host *)llist_first_entry(&bts->bsc_oml_hosts, struct bsc_oml_host, list);
 	else if (priv->current_bsc != last)
 		priv->current_bsc = (struct bsc_oml_host *)llist_entry(priv->current_bsc->list.next, struct bsc_oml_host, list);
-	else
-		return -1; /* We are so far not starting over the list when we reach the list, but only exit */
 
 	return 0;
 }
@@ -199,7 +199,7 @@ static void abis_link_connecting(struct osmo_fsm_inst *fi, uint32_t event, void
 		break;
 	case ABIS_LINK_EV_SIGN_LINK_DOWN:
 		reset_oml_link(bts);
-		osmo_fsm_inst_state_chg(fi, ABIS_LINK_ST_CONNECTING, 0, 0);
+		osmo_fsm_inst_state_chg(fi, ABIS_LINK_ST_WAIT_RECONNECT, OML_RETRY_TIMER, 0);
 		break;
 	default:
 		OSMO_ASSERT(0);
@@ -262,14 +262,32 @@ static void abis_link_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *d
 	}
 }
 
+int abis_link_fsm_timer_cb(struct osmo_fsm_inst *fi)
+{
+	switch (fi->state) {
+	case ABIS_LINK_ST_WAIT_RECONNECT:
+		osmo_fsm_inst_state_chg(fi, ABIS_LINK_ST_CONNECTING, 0, 0);
+		break;
+	default:
+		OSMO_ASSERT(0);
+	}
+	return 0;
+}
+
+
 static struct osmo_fsm_state abis_link_fsm_states[] = {
+	[ABIS_LINK_ST_WAIT_RECONNECT] = {
+		.name = "WAIT_RECONNECT",
+		.out_state_mask =
+			S(ABIS_LINK_ST_CONNECTING),
+	},
 	[ABIS_LINK_ST_CONNECTING] = {
 		.name = "CONNECTING",
 		.in_event_mask =
 			S(ABIS_LINK_EV_SIGN_LINK_OML_UP) |
 			S(ABIS_LINK_EV_SIGN_LINK_DOWN),
 		.out_state_mask =
-			S(ABIS_LINK_ST_CONNECTING) |
+			S(ABIS_LINK_ST_WAIT_RECONNECT) |
 			S(ABIS_LINK_ST_CONNECTED) |
 			S(ABIS_LINK_ST_FAILED),
 		.onenter = abis_link_connecting_onenter,
@@ -298,6 +316,7 @@ static struct osmo_fsm abis_link_fsm = {
 	.event_names = abis_link_fsm_event_names,
 	.allstate_action = abis_link_allstate,
 	.allstate_event_mask = S(ABIS_LINK_EV_VTY_RM_ADDR),
+	.timer_cb = abis_link_fsm_timer_cb,
 };
 
 int abis_oml_sendmsg(struct msgb *msg)