ipa: Fix client setting unit_id with ASP name instead of AS

This was broken since ever. The client was submitting the ASP name
 in the unit_id field during IPA handshake, and the server was
expecting it to contain the AS, so it failed with message:
"Cannot find any definition for IPA Unit Name '%s'" in
ipa_asp_fsm_wait_id_resp().

Fixes: 5f0a8df34cae20455a520c3a85cf94124f486bf2
Change-Id: I249964e171f578726439c40e01ae85aa447afada
---
M src/ipa.c
M src/xua_asp_fsm.c
M src/xua_internal.h
3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/src/ipa.c b/src/ipa.c
index a77d331..82ece8b 100644
--- a/src/ipa.c
+++ b/src/ipa.c
@@ -131,7 +131,7 @@
 	return 0;
 }
 
-static struct osmo_ss7_as *find_as_for_asp(struct osmo_ss7_asp *asp)
+struct osmo_ss7_as *ipa_find_as_for_asp(struct osmo_ss7_asp *asp)
 {
 	struct osmo_ss7_as *as;
 
@@ -216,7 +216,7 @@
 	int rc;
 	struct m3ua_data_hdr data_hdr;
 	struct xua_msg *xua;
-	struct osmo_ss7_as *as = find_as_for_asp(asp);
+	struct osmo_ss7_as *as = ipa_find_as_for_asp(asp);
 	uint32_t opc, dpc;
 
 	if (!as) {
diff --git a/src/xua_asp_fsm.c b/src/xua_asp_fsm.c
index 2d81bc3..cc94ac7 100644
--- a/src/xua_asp_fsm.c
+++ b/src/xua_asp_fsm.c
@@ -1190,10 +1190,16 @@
 {
 	struct osmo_fsm_inst *fi;
 	struct ipa_asp_fsm_priv *iafp;
+	struct osmo_ss7_as *as = ipa_find_as_for_asp(asp);
 
 	/* allocate as child of AS? */
 	fi = osmo_fsm_inst_alloc(&ipa_asp_fsm, asp, NULL, log_level, asp->cfg.name);
 
+	if (!as) {
+		osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
+		return NULL;
+	}
+
 	iafp = talloc_zero(fi, struct ipa_asp_fsm_priv);
 	if (!iafp) {
 		osmo_fsm_inst_term(fi, OSMO_FSM_TERM_ERROR, NULL);
@@ -1202,7 +1208,7 @@
 	iafp->role = role;
 	iafp->asp = asp;
 	iafp->ipa_unit = talloc_zero(iafp, struct ipaccess_unit);
-	iafp->ipa_unit->unit_name = talloc_strdup(iafp->ipa_unit, asp->cfg.name);
+	iafp->ipa_unit->unit_name = talloc_strdup(iafp->ipa_unit, as->cfg.name);
 	iafp->pong_timer.cb = ipa_pong_timer_cb;
 	iafp->pong_timer.data = fi;
 
diff --git a/src/xua_internal.h b/src/xua_internal.h
index 93f6140..b6b33af 100644
--- a/src/xua_internal.h
+++ b/src/xua_internal.h
@@ -117,6 +117,7 @@
 
 int ipa_tx_xua_as(struct osmo_ss7_as *as, struct xua_msg *xua);
 int ipa_rx_msg(struct osmo_ss7_asp *asp, struct msgb *msg, uint8_t sls);
+struct osmo_ss7_as *ipa_find_as_for_asp(struct osmo_ss7_asp *asp);
 
 int osmo_isup_party_parse(char *out_digits, const uint8_t *in,
 			unsigned int in_num_bytes, bool odd);

