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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
This commit is contained in:
Philipp Maier 2018-03-13 13:07:45 +01:00
parent 3a74128ccc
commit 4eef20bdbc
1 changed files with 58 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

98
src/libmsc/msc_mgcp.c
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@ -58,6 +58,7 @@ enum msc_mgcp_cause_code {
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 @@ static const struct value_string msc_mgcp_cause_codes_names[] = {
{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 @@ static const struct value_string msc_mgcp_fsm_evt_names[] = {
* 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 @@ static void _handle_error(struct mgcp_ctx *mgcp_ctx, enum msc_mgcp_cause_code ca
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);
/* 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);
/* 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);
}
/* 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 @@ static int fsm_timeout_cb(struct osmo_fsm_inst *fi)
/* 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 @@ static int fsm_timeout_cb(struct osmo_fsm_inst *fi)
} 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 @@ static void fsm_crcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data
};
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 @@ static void fsm_crcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data
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 @@ static void mgw_crcx_ran_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void mgw_crcx_ran_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void fsm_crcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void fsm_crcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
};
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 @@ static void fsm_crcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void mgw_crcx_cn_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void mgw_crcx_cn_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void fsm_crcx_compl(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void fsm_crcx_compl(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void fsm_mdcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void fsm_mdcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
};
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 @@ static void fsm_mdcx_cn_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void mgw_mdcx_cn_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void fsm_mdcx_cn_compl_cb(struct osmo_fsm_inst *fi, uint32_t event, void
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 @@ static void fsm_mdcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data
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 @@ static void fsm_mdcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data
};
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 @@ static void fsm_mdcx_ran_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data
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 @@ static void mgw_mdcx_ran_resp_cb(struct mgcp_response *r, void *priv)
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 @@ static void fsm_mdcx_ran_compl_cb(struct osmo_fsm_inst *fi, uint32_t event, void
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 @@ static void fsm_call_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
};
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 @@ static void fsm_call_cb(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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 @@ static void mgw_dlcx_all_resp_cb(struct mgcp_response *r, void *priv)
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;
}