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mgcp: Do not detect the initial package as a wrap around 

The Annex A code has a probation period but we don't have it. When
starting with seq_no==0 do not assume that the sequence numbers
have wrapped. Do it by moving the entire checking code into the
else.
This commit is contained in:
Holger Hans Peter Freyther 2014-10-06 21:01:26 +02:00
parent a5a59c9a05
commit 05d481a42c
4 changed files with 66 additions and 19 deletions
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5
openbsc/include/openbsc/mgcp_internal.h
View File

@ -248,6 +248,11 @@ void mgcp_get_net_downlink_format_default(struct mgcp_endpoint *endp,
const char**subtype_name,
const char**fmtp_extra);
/* internal RTP Annex A counting */
void mgcp_rtp_annex_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *state,
const uint16_t seq, const int32_t transit,
const uint32_t ssrc);
enum {
MGCP_DEST_NET = 0,
MGCP_DEST_BTS,

39
openbsc/src/libmgcp/mgcp_network.c
View File

@ -336,7 +336,6 @@ void mgcp_rtp_annex_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
const uint16_t seq, const int32_t transit,
const uint32_t ssrc)
{
uint16_t udelta;
int32_t d;
/* initialize or re-initialize */
@ -348,25 +347,27 @@ void mgcp_rtp_annex_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
state->stats_jitter = 0;
state->stats_transit = transit;
state->stats_cycles = 0;
}
} else {
uint16_t udelta;
/*
* The below takes the shape of the validation of
* Appendix A. Check if there is something weird with
* the sequence number, otherwise check for a wrap
* around in the sequence number.
* It can't wrap during the initialization so let's
* skip it here. The Appendix A probably doesn't have
* this issue because of the probation.
*/
udelta = seq - state->stats_max_seq;
if (udelta < RTP_MAX_DROPOUT) {
if (seq < state->stats_max_seq)
state->stats_cycles += RTP_SEQ_MOD;
} else if (udelta <= RTP_SEQ_MOD - RTP_MAX_MISORDER) {
LOGP(DMGCP, LOGL_NOTICE,
"RTP seqno made a very large jump on 0x%x delta: %u\n",
ENDPOINT_NUMBER(endp), udelta);
/*
* The below takes the shape of the validation of
* Appendix A. Check if there is something weird with
* the sequence number, otherwise check for a wrap
* around in the sequence number.
* It can't wrap during the initialization so let's
* skip it here. The Appendix A probably doesn't have
* this issue because of the probation.
*/
udelta = seq - state->stats_max_seq;
if (udelta < RTP_MAX_DROPOUT) {
if (seq < state->stats_max_seq)
state->stats_cycles += RTP_SEQ_MOD;
} else if (udelta <= RTP_SEQ_MOD - RTP_MAX_MISORDER) {
LOGP(DMGCP, LOGL_NOTICE,
"RTP seqno made a very large jump on 0x%x delta: %u\n",
ENDPOINT_NUMBER(endp), udelta);
}
}
/*

40
openbsc/tests/mgcp/mgcp_test.c
View File

@ -998,6 +998,45 @@ static void test_multilple_codec(void)
talloc_free(cfg);
}
static void test_no_cycle(void)
{
struct mgcp_config *cfg;
struct mgcp_endpoint *endp;
printf("Testing no sequence flow on initial packet\n");
cfg = mgcp_config_alloc();
cfg->trunk.number_endpoints = 64;
mgcp_endpoints_allocate(&cfg->trunk);
endp = &cfg->trunk.endpoints[1];
OSMO_ASSERT(endp->net_state.stats_initialized == 0);
mgcp_rtp_annex_count(endp, &endp->net_state, 0, 0, 2342);
OSMO_ASSERT(endp->net_state.stats_initialized == 1);
OSMO_ASSERT(endp->net_state.stats_cycles == 0);
OSMO_ASSERT(endp->net_state.stats_max_seq == 0);
mgcp_rtp_annex_count(endp, &endp->net_state, 1, 0, 2342);
OSMO_ASSERT(endp->net_state.stats_initialized == 1);
OSMO_ASSERT(endp->net_state.stats_cycles == 0);
OSMO_ASSERT(endp->net_state.stats_max_seq == 1);
/* now jump.. */
mgcp_rtp_annex_count(endp, &endp->net_state, UINT16_MAX, 0, 2342);
OSMO_ASSERT(endp->net_state.stats_initialized == 1);
OSMO_ASSERT(endp->net_state.stats_cycles == 0);
OSMO_ASSERT(endp->net_state.stats_max_seq == UINT16_MAX);
/* and wrap */
mgcp_rtp_annex_count(endp, &endp->net_state, 0, 0, 2342);
OSMO_ASSERT(endp->net_state.stats_initialized == 1);
OSMO_ASSERT(endp->net_state.stats_cycles == UINT16_MAX + 1);
OSMO_ASSERT(endp->net_state.stats_max_seq == 0);
talloc_free(cfg);
}
int main(int argc, char **argv)
{
osmo_init_logging(&log_info);
@ -1014,6 +1053,7 @@ int main(int argc, char **argv)
test_packet_error_detection(0, 1);
test_packet_error_detection(1, 1);
test_multilple_codec();
test_no_cycle();
printf("Done\n");
return EXIT_SUCCESS;

1
openbsc/tests/mgcp/mgcp_test.ok
View File

@ -475,4 +475,5 @@ In TS: 160320, dTS: 160, Seq: 1002
Out TS change: 160, dTS: 160, Seq change: 1, TS Err change: in +0, out +0
Stats: Jitter = 6810, Transit = -144000
Testing multiple payload types
Testing no sequence flow on initial packet
Done