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dexter gerrit-no-reply at lists.osmocom.org
Review at https://gerrit.osmocom.org/7277
msc_mgcp: fix mgw timeout handling
When the MGW does not respond to an MGCP message then the mgcp FSM
terminates, but the CC handler (gsm_04_08.c) is not informed. This
lets the CC handler think that the MGCP connection would be successful,
so it also does not take any action to release the non functional
connection.
- make sure the CC handler is always informed on any kind of
error, especially on MGW timeouts
Change-Id: I3fcd0d71fad53274e82f6d87c80042d06283bc5d
Related OS#2881
Related OS#2882
---
M src/libmsc/msc_mgcp.c
1 file changed, 58 insertions(+), 40 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-msc refs/changes/77/7277/1
diff --git a/src/libmsc/msc_mgcp.c b/src/libmsc/msc_mgcp.c
index 3ac30c4..738d1b8 100644
--- a/src/libmsc/msc_mgcp.c
+++ b/src/libmsc/msc_mgcp.c
@@ -58,6 +58,7 @@
MGCP_ERR_MGW_FAIL,
MGCP_ERR_MGW_INVAL_RESP,
MGCP_ERR_MGW_TX_FAIL,
+ MGCP_ERR_MGW_TIMEOUT,
MGCP_ERR_UNEXP_TEARDOWN,
MGCP_ERR_UNSUPP_ADDR_FMT,
MGCP_ERR_RAN_TIMEOUT,
@@ -72,6 +73,7 @@
{MGCP_ERR_MGW_FAIL, "operation failed on MGW"},
{MGCP_ERR_MGW_INVAL_RESP, "invalid / unparseable response from MGW"},
{MGCP_ERR_MGW_TX_FAIL, "failed to transmit MGCP message to MGW"},
+ {MGCP_ERR_MGW_TIMEOUT, "request to MGW timed out"},
{MGCP_ERR_UNEXP_TEARDOWN, "unexpected connection teardown"},
{MGCP_ERR_UNSUPP_ADDR_FMT, "unsupported network address format used (RAN)"},
{MGCP_ERR_RAN_TIMEOUT, "call could not be completed in time (RAN)"},
@@ -150,11 +152,9 @@
* remove a half open connection (if possible). This function will execute
* a controlled jump to the DLCX phase. From there, the FSM will then just
* continue like the call were ended normally */
-
-#define handle_error(mgcp_ctx, cause) \
- _handle_error(mgcp_ctx, cause, __FILE__, __LINE__)
-static void _handle_error(struct mgcp_ctx *mgcp_ctx, enum msc_mgcp_cause_code cause,
- const char *file, int line)
+#define handle_error(mgcp_ctx, cause, dlcx) _handle_error(mgcp_ctx, cause, dlcx, __FILE__, __LINE__)
+static void _handle_error(struct mgcp_ctx *mgcp_ctx, enum msc_mgcp_cause_code cause, bool dlcx, const char *file,
+ int line)
{
struct osmo_fsm_inst *fi;
struct gsm_mncc mncc = {
@@ -174,13 +174,32 @@
LOGPFSMLSRC(mgcp_ctx->fsm, LOGL_ERROR, file, line, "%s -- graceful shutdown...\n",
get_value_string(msc_mgcp_cause_codes_names, cause));
- /* Set the VM into the state where it waits for the call end */
- osmo_fsm_inst_state_chg(fi, ST_CALL, 0, 0);
+ /* For the shutdown we have two options. Whenever it makes sense to
+ * send a DLCX to the MGW in order to be sure that the connection is
+ * properly cleaned up, the dlcx flag should be set. In other cases
+ * where a DLCX does not make sense (e.g. the MGW times out), halting
+ * directly is the better options. In those cases, the dlcx flag
+ * should not be set */
+ if (dlcx) {
+ /* Fast-forward the FSM into call state. In this state the FSM
+ * expects either an EV_TEARDOWN or an EV_TEARDOWN_ERROR. When
+ * one of the two events is received a DLCX will be send to
+ * the MGW. After that. The FSM automatically halts but will
+ * still expect a call msc_mgcp_call_release() to be freed
+ * completely */
+ osmo_fsm_inst_state_chg(fi, ST_CALL, 0, 0);
+ osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_TEARDOWN_ERROR, mgcp_ctx);
+ } else {
+ /* Halt the state machine immediately. The FSM will not be
+ * freed yet, we stil require the higher layers to call
+ * msc_mgcp_call_release() */
+ osmo_fsm_inst_state_chg(fi, ST_HALT, 0, 0);
+ osmo_fsm_inst_dispatch(fi, EV_TEARDOWN_ERROR, mgcp_ctx);
+ }
- /* Simulate the call end by sending a teardown event, so that
- * the FSM proceeds directly with the DLCX */
- osmo_fsm_inst_dispatch(mgcp_ctx->fsm, EV_TEARDOWN_ERROR, mgcp_ctx);
-
+ /* Request the higher layers to release the call */
+ mncc_set_cause(&mncc, GSM48_CAUSE_LOC_TRANS_NET,
+ GSM48_CC_CAUSE_RESOURCE_UNAVAIL);
mncc_tx_to_cc(mgcp_ctx->trans->net, MNCC_REL_REQ, &mncc);
}
@@ -205,14 +224,13 @@
/* Cancel the transaction that timed out */
mgcp_client_cancel(mgcp, mgcp_ctx->mgw_pending_trans);
- /* Initiate self destruction of the FSM */
- osmo_fsm_inst_state_chg(fi, ST_HALT, 0, 0);
- osmo_fsm_inst_dispatch(fi, EV_TEARDOWN_ERROR, mgcp_ctx);
+ /* halt of the FSM */
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TIMEOUT, false);
} else if (fi->T == MGCP_RAN_TIMEOUT_TIMER_NR) {
/* If the logic that controls the RAN is unable to negotiate a
* connection, we presumably still have a working connection to
* the MGW, we will try to shut down gracefully. */
- handle_error(mgcp_ctx, MGCP_ERR_RAN_TIMEOUT);
+ handle_error(mgcp_ctx, MGCP_ERR_RAN_TIMEOUT, true);
} else if (fi->T == MGCP_REL_TIMEOUT_TIMER_NR) {
/* Under normal conditions, the MSC logic should always command
* to release the call at some point. However, the release may
@@ -228,7 +246,7 @@
} else if (fi->T == MGCP_ASS_TIMEOUT_TIMER_NR) {
/* There may be rare cases in which the MSC is unable to
* complete the call assignment */
- handle_error(mgcp_ctx, MGCP_ERR_ASS_TIMEOUT);
+ handle_error(mgcp_ctx, MGCP_ERR_ASS_TIMEOUT, true);
} else {
/* Ther must not be any unsolicited timers in this FSM. If so,
* we have serious problem. */
@@ -267,7 +285,7 @@
};
if (snprintf(mgcp_msg.endpoint, MGCP_ENDPOINT_MAXLEN, MGCP_ENDPOINT_FORMAT, mgcp_ctx->rtp_endpoint) >=
MGCP_ENDPOINT_MAXLEN) {
- handle_error(mgcp_ctx, MGCP_ERR_NOMEM);
+ handle_error(mgcp_ctx, MGCP_ERR_NOMEM, true);
return;
}
msg = mgcp_msg_gen(mgcp, &mgcp_msg);
@@ -277,7 +295,7 @@
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_crcx_ran_resp_cb, mgcp_ctx);
if (rc < 0) {
- handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true);
return;
}
@@ -301,7 +319,7 @@
if (r->head.response_code != 200) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR,
"CRCX/RAN: response yields error: %d %s\n", r->head.response_code, r->head.comment);
- handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true);
return;
}
@@ -312,7 +330,7 @@
rc = mgcp_response_parse_params(r);
if (rc) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/RAN: Cannot parse response\n");
- handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP, true);
return;
}
@@ -344,7 +362,7 @@
case EV_CRCX_RAN_RESP:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -360,7 +378,7 @@
};
if (snprintf(mgcp_msg.endpoint, MGCP_ENDPOINT_MAXLEN, MGCP_ENDPOINT_FORMAT, mgcp_ctx->rtp_endpoint) >=
MGCP_ENDPOINT_MAXLEN) {
- handle_error(mgcp_ctx, MGCP_ERR_NOMEM);
+ handle_error(mgcp_ctx, MGCP_ERR_NOMEM, true);
return;
}
msg = mgcp_msg_gen(mgcp, &mgcp_msg);
@@ -370,7 +388,7 @@
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_crcx_cn_resp_cb, mgcp_ctx);
if (rc < 0) {
- handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true);
return;
}
@@ -394,7 +412,7 @@
if (r->head.response_code != 200) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR,
"CRCX/CN: response yields error: %d %s\n", r->head.response_code, r->head.comment);
- handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true);
return;
}
@@ -405,7 +423,7 @@
rc = mgcp_response_parse_params(r);
if (rc) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR, "CRCX/CN: Cannot parse response\n");
- handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_INVAL_RESP, true);
return;
}
@@ -435,7 +453,7 @@
case EV_CRCX_CN_RESP:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -473,7 +491,7 @@
return;
error:
- handle_error(mgcp_ctx, MGCP_ERR_ASSGMNT_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_ASSGMNT_FAIL, true);
}
static void mgw_mdcx_cn_resp_cb(struct mgcp_response *r, void *priv);
@@ -501,7 +519,7 @@
case EV_CONNECT:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -523,7 +541,7 @@
};
if (snprintf(mgcp_msg.endpoint, MGCP_ENDPOINT_MAXLEN, MGCP_ENDPOINT_FORMAT, mgcp_ctx->rtp_endpoint) >=
MGCP_ENDPOINT_MAXLEN) {
- handle_error(mgcp_ctx, MGCP_ERR_NOMEM);
+ handle_error(mgcp_ctx, MGCP_ERR_NOMEM, true);
return;
}
msg = mgcp_msg_gen(mgcp, &mgcp_msg);
@@ -533,7 +551,7 @@
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_mdcx_cn_resp_cb, mgcp_ctx);
if (rc < 0) {
- handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true);
return;
}
@@ -550,7 +568,7 @@
if (r->head.response_code != 200) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR,
"MDCX/CN: response yields error: %d %s\n", r->head.response_code, r->head.comment);
- handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true);
return;
}
@@ -577,7 +595,7 @@
case EV_MDCX_CN_RESP:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -617,7 +635,7 @@
case EV_ASSIGN:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -639,7 +657,7 @@
};
if (snprintf(mgcp_msg.endpoint, MGCP_ENDPOINT_MAXLEN, MGCP_ENDPOINT_FORMAT, mgcp_ctx->rtp_endpoint) >=
MGCP_ENDPOINT_MAXLEN) {
- handle_error(mgcp_ctx, MGCP_ERR_NOMEM);
+ handle_error(mgcp_ctx, MGCP_ERR_NOMEM, true);
return;
}
msg = mgcp_msg_gen(mgcp, &mgcp_msg);
@@ -649,7 +667,7 @@
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_mdcx_ran_resp_cb, mgcp_ctx);
if (rc < 0) {
- handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true);
return;
}
@@ -666,7 +684,7 @@
if (r->head.response_code != 200) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR,
"MDCX/RAN: response yields error: %d %s\n", r->head.response_code, r->head.comment);
- handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true);
return;
}
@@ -684,7 +702,7 @@
case EV_MDCX_RAN_RESP:
break;
default:
- handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN);
+ handle_error(mgcp_ctx, MGCP_ERR_UNEXP_TEARDOWN, true);
return;
}
@@ -723,7 +741,7 @@
};
if (snprintf(mgcp_msg.endpoint, MGCP_ENDPOINT_MAXLEN, MGCP_ENDPOINT_FORMAT, mgcp_ctx->rtp_endpoint) >=
MGCP_ENDPOINT_MAXLEN) {
- handle_error(mgcp_ctx, MGCP_ERR_NOMEM);
+ handle_error(mgcp_ctx, MGCP_ERR_NOMEM, true);
return;
}
msg = mgcp_msg_gen(mgcp, &mgcp_msg);
@@ -733,7 +751,7 @@
mgcp_ctx->mgw_pending_trans = mgcp_msg_trans_id(msg);
rc = mgcp_client_tx(mgcp, msg, mgw_dlcx_all_resp_cb, mgcp_ctx);
if (rc < 0) {
- handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_TX_FAIL, true);
return;
}
@@ -751,7 +769,7 @@
if (r->head.response_code != 200 && r->head.response_code != 250) {
LOGPFSML(mgcp_ctx->fsm, LOGL_ERROR,
"DLCX: response yields error: %d %s\n", r->head.response_code, r->head.comment);
- handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL);
+ handle_error(mgcp_ctx, MGCP_ERR_MGW_FAIL, true);
return;
}
--
To view, visit https://gerrit.osmocom.org/7277
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I3fcd0d71fad53274e82f6d87c80042d06283bc5d
Gerrit-PatchSet: 1
Gerrit-Project: osmo-msc
Gerrit-Branch: master
Gerrit-Owner: dexter <pmaier at sysmocom.de>