From 83d6c2f0e438ec4129bddb9a54ce9dd2777c0748 Mon Sep 17 00:00:00 2001
From: Stefan Sperling <ssperling@sysmocom.de>
Date: Wed, 14 Feb 2018 19:46:33 +0100
Subject: Make osmo-pcu wait for BTS to become available at start-up time.

After the PCU socket becomes available, the BTS might send an
INFO_IND message with the 'ACTIVE' flag cleared. If this happens,
do not exit immediately, but keep retrying until an INFO_IND
message with the 'ACTIVE' flag arrives.

Note that this change only affects behaviour at process start-up time.
If the BTS switches from active to inactive state then osmo-pcu will
still exit. If this behaviour should be changed as well it could be
done in a follow-up patch.

Tested against osom-bsc + osmo-bts-virtual.

Change-Id: Ic42a5601a43b81d260721fef5d9fa52447f9d309
Related: OS#2689
---
 src/bts.h            |  1 +
 src/osmobts_sock.cpp | 29 ++++++++++++++++++++++-------
 src/pcu_l1_if.cpp    |  4 ++++
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/src/bts.h b/src/bts.h
index 5679b988..f9f385b7 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -173,6 +173,7 @@ void bts_update_tbf_ta(const char *p, uint32_t fn, uint8_t trx_no, uint8_t ts, i
  * we can start to compile pcu_vty.c with c++ and remove the split.
  */
 struct gprs_rlcmac_bts {
+	bool active;
 	uint8_t bsic;
 	uint8_t fc_interval;
 	uint16_t fc_bucket_time;
diff --git a/src/osmobts_sock.cpp b/src/osmobts_sock.cpp
index 577d41eb..9e4000a0 100644
--- a/src/osmobts_sock.cpp
+++ b/src/osmobts_sock.cpp
@@ -55,7 +55,23 @@ struct pcu_sock_state {
 	struct llist_head upqueue;	/* queue for sending messages */
 } *pcu_sock_state = NULL;
 
-static void pcu_sock_timeout(void *_priv);
+static void pcu_sock_timeout(void *_priv)
+{
+	pcu_l1if_open();
+}
+
+static void pcu_tx_txt_retry(void *_priv)
+{
+	struct gprs_rlcmac_bts *bts = bts_main_data();
+	struct pcu_sock_state *state = pcu_sock_state;
+
+	if (bts->active)
+		return;
+
+	LOGP(DL1IF, LOGL_INFO, "Sending version %s to BTS.\n", PACKAGE_VERSION);
+	pcu_tx_txt_ind(PCU_VERSION, "%s", PACKAGE_VERSION);
+	osmo_timer_schedule(&state->timer, 5, 0);
+}
 
 int pcu_sock_send(struct msgb *msg)
 {
@@ -268,7 +284,7 @@ int pcu_l1if_open(void)
 		pcu_sock_state = state;
 		close(bfd->fd);
 		bfd->fd = -1;
-		state->timer.cb = pcu_sock_timeout;
+		osmo_timer_setup(&state->timer, pcu_sock_timeout, NULL);
 		osmo_timer_schedule(&state->timer, 5, 0);
 		return 0;
 	}
@@ -293,6 +309,10 @@ int pcu_l1if_open(void)
 	LOGP(DL1IF, LOGL_INFO, "Sending version %s to BTS.\n", PACKAGE_VERSION);
 	pcu_tx_txt_ind(PCU_VERSION, "%s", PACKAGE_VERSION);
 
+	/* Schedule a timer so we keep trying until the BTS becomes active. */
+	osmo_timer_setup(&state->timer, pcu_tx_txt_retry, NULL);
+	osmo_timer_schedule(&state->timer, 5, 0);
+
 	return 0;
 }
 
@@ -312,8 +332,3 @@ void pcu_l1if_close(void)
 	talloc_free(state);
 	pcu_sock_state = NULL;
 }
-
-static void pcu_sock_timeout(void *_priv)
-{
-	pcu_l1if_open();
-}
diff --git a/src/pcu_l1_if.cpp b/src/pcu_l1_if.cpp
index 7112b044..0a9803b1 100644
--- a/src/pcu_l1_if.cpp
+++ b/src/pcu_l1_if.cpp
@@ -414,7 +414,10 @@ static int pcu_rx_info_ind(struct gsm_pcu_if_info_ind *info_ind)
 
 	if (!(info_ind->flags & PCU_IF_FLAG_ACTIVE)) {
 		LOGP(DL1IF, LOGL_NOTICE, "BTS not available\n");
+		if (!bts->active)
+			return -EAGAIN;
 bssgp_failed:
+		bts->active = false;
 		/* free all TBF */
 		for (trx = 0; trx < ARRAY_SIZE(bts->trx); trx++) {
 			bts->trx[trx].arfcn = info_ind->trx[trx].arfcn;
@@ -562,6 +565,7 @@ bssgp_failed:
 		}
 	}
 
+	bts->active = true;
 	return rc;
 }
 
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