It seems that I slipped a nasty bug into the CAPI support. The message

lengths for CONNECT_REQ and CONNECT_IND are incorrect, which causes
dialouts to fail after certain error situations (an invalid -- not
wrong! -- number has been dialed). Since these messages are tagged as
too short, the device reads trailing garbage as the B protocol
parameters; this is OK as long as the garbage consists of zero bytes,
which it usually does, except after the said error.

Another change we have taken into use is to send an explicit Q.850
"normal call clearing" code when a call is ignored using PRI equipment
(specifically AVM T1); the CAPI pseudo-code for ignore, 1, translates
into something at least Ericsson exchanges interpret oddly (message
"this area is not reachable from your number"). NCCLR makes the exchange
give a busy signal, which is the behaviour at least we prefer
(conceivably, the ignore code could be made a sysctl variable).

The attached patch corrects the message length issue. It also includes a
somewhat unpretty solution for the PRI ignore code (if device's number
of channels equals 30, assume PRI and send NCCLR, otherwise send CAPI
ignore). Tested using AVM B1 PCI and T1 PCI.

Submitted by:	Juha-Matti Liukkonen <jml@cubical.fi>
Reviewed by:	hm
MFC after:	1 month

1 files changed, 9 insertions, 4 deletions

diff --git a/sys/i4b/capi/capi_msgs.c b/sys/i4b/capi/capi_msgs.c
index a2ce023..5c1698f 100644
--- a/sys/i4b/capi/capi_msgs.c
+++ b/sys/i4b/capi/capi_msgs.c
@@ -195,7 +195,7 @@ void capi_connect_req(capi_softc_t *sc, call_desc_t *cd)
     int slen = strlen(cd->src_telno);
     int dlen = strlen(cd->dst_telno);
 
-    m = i4b_Dgetmbuf(8 + 18 + slen + dlen);
+    m = i4b_Dgetmbuf(8 + 27 + slen + dlen);
     if (!m) {
 	printf("capi%d: can't get mbuf for connect_req\n", sc->sc_unit);
 	return;
@@ -566,7 +566,7 @@ void capi_connect_resp(capi_softc_t *sc, call_desc_t *cd)
     u_int32_t PLCI;
     int dlen = strlen(cd->dst_telno);
 
-    m = i4b_Dgetmbuf(8 + 11 + dlen);
+    m = i4b_Dgetmbuf(8 + 21 + dlen);
     if (!m) {
 	printf("capi%d: can't get mbuf for connect_resp\n", sc->sc_unit);
 	return;
@@ -600,7 +600,12 @@ void capi_connect_resp(capi_softc_t *sc, call_desc_t *cd)
     case SETUP_RESP_DNTCRE:
 	sc->sc_bchan[cd->channelid].state = B_FREE;
 	ctrl_desc[sc->ctrl_unit].bch_state[cd->channelid] = BCH_ST_FREE;
-	msg = capimsg_setu16(msg, 1); /* Ignore */
+	if (sc->sc_nbch == 30) {
+	    /* With PRI, we can't really ignore calls  -- normal clearing */
+	    msg = capimsg_setu16(msg, (0x3480|CAUSE_Q850_NCCLR));
+	} else {
+	    msg = capimsg_setu16(msg, 1); /* Ignore */
+	}
 	break;
 
     default:
@@ -733,7 +738,7 @@ void capi_data_b3_conf(capi_softc_t *sc, struct mbuf *m_in)
 
 void capi_data_b3_ind(capi_softc_t *sc, struct mbuf *m_in)
 {
-    struct mbuf *m = i4b_Dgetmbuf(8 + 14);
+    struct mbuf *m = i4b_Dgetmbuf(8 + 6);
     u_int8_t *msg = mtod(m_in, u_int8_t*);
     u_int16_t applid, msgid;
     u_int32_t NCCI;