Currently chan_ss7 doesn't give a cow when the caller gets a "no charge"
in the backwards call indicator field and sends an answer frame to the
calling channel in any case. I made this patch to fix it. It just
records the charge indicator received in the ACM response in a field in
the pvt struct, and when the ANM arrives, it abstains from forwarding
the answer frame if the previously recorded value was 2 (no charge).
I tested it calling an invalid number from a SIP ATA and it works OK. I
hear the other phone company's recording as early media and the call is
no longer billed. I tested in 0.9, but the patch applies to 1.0.0 too.
This patch is GPL v2 and (C) Instant Solutions Ltda. of Brazil.
Juan Carlos Castro y Castro
Instant Solution Ltda. <http://www.instant.com.br/>
Rio de Janeiro - Brazil
Index: l4isup.c
===================================================================
--- l4isup.c (revision 5275)
+++ l4isup.c (working copy)
@@ -109,6 +109,7 @@
int reset_done; /* False until circuit has been init reset */
int hangupcause;
int has_inband_ind;
+ int charge_indicator;
/* Circuit blocking status: {local,remote} {maintenance,hardware}. */
enum { BL_LM=1, BL_LH=2, BL_RM=4, BL_RH=8, BL_UNEQUIPPED=0x10, BL_LINKDOWN=0x20 } blocked;
/* Circuit equipped */
@@ -2557,6 +2558,8 @@
}
t9_start(chan);
+ pvt->charge_indicator = inmsg->acm.back_ind.charge_indicator;
+
/* Q.764 (2.1.4.6 a): Alert if called_party_status is "subscriber free". */
if(inmsg->acm.back_ind.called_party_status == 1) {
ast_queue_frame(chan, &ring_frame);
@@ -2569,7 +2572,6 @@
static void process_anm(struct ss7_chan *pvt, struct isup_msg *inmsg)
{
struct ast_channel* chan = pvt->owner;
- static struct ast_frame answer_frame = { AST_FRAME_CONTROL, AST_CONTROL_ANSWER };
/* Q.764 (2.1.7.6): When receiving ANM, stop T9. */
t9_clear(pvt);
@@ -2593,9 +2595,14 @@
zt_enable_ec(pvt);
}
- ast_queue_frame(chan, &answer_frame);
- pvt->state = ST_CONNECTED;
- ast_setstate(chan, AST_STATE_UP);
+ if (pvt->charge_indicator == 1) {
+ ast_log(LOG_DEBUG, "We previously had a \"no charge\" charge indicator at CIC=%d!\n", pvt->cic);
+ } else {
+ static struct ast_frame answer_frame = { AST_FRAME_CONTROL, AST_CONTROL_ANSWER };
+ ast_queue_frame(chan, &answer_frame);
+ pvt->state = ST_CONNECTED;
+ ast_setstate(chan, AST_STATE_UP);
+ }
check_obci(pvt, inmsg->anm.obc_ind);
}
@@ -3879,6 +3886,7 @@
pvt->echocan_start = 0;
pvt->echocancel = 0;
pvt->has_inband_ind = 0;
+ pvt->charge_indicator = 0;
pvt->grs_count = -1;
pvt->cgb_mask = 0;
memset(pvt->context, 0, sizeof(pvt->context));
Index: isup.c
===================================================================
--- isup.c (revision 5275)
+++ isup.c (working copy)
@@ -240,6 +240,7 @@
return 0;
}
ind_ptr->called_party_status = (p[0] >> 2) & 0x3;
+ ind_ptr->charge_indicator = p[0] & 0x3;
return 1;
}
Index: isup.h
===================================================================
--- isup.h (revision 5275)
+++ isup.h (working copy)
@@ -94,6 +94,7 @@
/* Fields in a "backwards call indicators" parameter (ACM). */
struct isup_backwards_call_ind {
int called_party_status;
+ int charge_indicator;
};
/* Fields in "redirection information" parameter. */
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