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Hi,<BR>
<BR>
Any retransmission will cause the problem, so anyone using UDP over the Internet to a Kamailio presence server where there is occasional packet-loss will see it. It was just first noticed here under heavy load.<BR>
<BR>
By creating a new transaction and absorbing the retransmissions, do you mean calling t_newtran()/t_release() when the SUBSCRIBE is received?<BR>
<BR>
If so I didn't think of that. It'd make sense to do that too. I think the presence module should cope with retransmissions (especially as we need it to cope in a multi-server environment with load-balancers/fail-over and a shared database). But if using t_newtran()/t_release() will handle retransmissions in the normal case it should help reduce the load on the database.<BR>
<BR>
Thanks,<BR>
<BR>
Peter<BR>
<BR>
<BR>
On Mon, 2012-01-30 at 18:26 +0100, Daniel-Constantin Mierla wrote:<BR>
<BLOCKQUOTE TYPE=CITE>
Hello,<BR>
<BR>
it can be held for next minor release to be tested more, if you feel it is better (we have to include something there as well :-) ). From commit log I understood is happening usually under RLS heavy load with retransmissions, does not help creating the transaction and absorbing the retransmissions with tm?<BR>
<BR>
Cheers,<BR>
Daniel<BR>
<BR>
On 1/30/12 6:19 PM, Peter Dunkley wrote: <BR>
<BLOCKQUOTE TYPE=CITE>
Hello,<BR>
<BR>
I believe that this bug also affects the 3.2 branch, but the change is quite big and with the next release of 3.2 due tomorrow I thought it best to hold off "cherry-pick"ing it until after the release. That is, unless anyone else thinks it should go in there?<BR>
<BR>
Regards,<BR>
<BR>
Peter<BR>
<BR>
On Mon, 2012-01-30 at 18:16 +0100, Peter Dunkley wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
Module: sip-router
Branch: master
Commit: e6a50c5c0957a5ad3e08e57ede5be775a41ac24f
URL: <A HREF="http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=e6a50c5c0957a5ad3e08e57ede5be775a41ac24f">http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=e6a50c5c0957a5ad3e08e57ede5be775a41ac24f</A>
Author: pd <<A HREF="mailto:peter.dunkley@crocodile-rcs.com">peter.dunkley@crocodile-rcs.com</A>>
Committer: pd <<A HREF="mailto:peter.dunkley@crocodile-rcs.com">peter.dunkley@crocodile-rcs.com</A>>
Date: Mon Jan 30 17:06:42 2012 +0000
modules_k/presence: Improved handling of retransmitted SUBSCRIBE requests
- handle_subscribe() doesn't handle retransmitted SUBSCRIBEs properly. This was
noticed with back-end SUBSCRIBEs from RLS under heavy load (also tried TCP
here but under-load this caused a different set of problems with buffer
sizes and buffers taking too long to process).
- Although this was originally observed with RLS back-end SUBSCRIBEs it
appears to be a general issue when UDP is used.
- There were two main problems:
1) On an un-SUBSCRIBE the record in the hash-table or DB will be removed. If
the un-SUBSCRIBE is retransmitted there is no record to be found and
handle_subscribe() fails.
2) After fixing 1, and on re-SUBSCRIBE, remote CSeq's with lower than
expected values cause failures. This can also happen when there are
retransmissions.
- The fix was to catch both these cases and treat them as a special class of
error. In these two cases and when the protocol is UDP, a correct-looking
2XX response is sent, but no further processing (database updates, sending
NOTIFY, and so on) is performed on the SUBSCRIBE request.
- Also modified the query in get_database_info() to just use Call-ID, To-tag,
and From-tag for dialog matching (so it duplicates the query from
get_stored_info()) as the query that was there looked a little aggressive.
---
modules_k/presence/subscribe.c | 247 +++++++++++++++++++++------------------
1 files changed, 133 insertions(+), 114 deletions(-)
diff --git a/modules_k/presence/subscribe.c b/modules_k/presence/subscribe.c
index d11287c..8add119 100644
--- a/modules_k/presence/subscribe.c
+++ b/modules_k/presence/subscribe.c
@@ -762,7 +762,10 @@ int handle_subscribe(struct sip_msg* msg, char* str1, char* str2)
{
if(get_stored_info(msg, &subs, &reply_code, &reply_str )< 0)
{
- LM_ERR("getting stored info\n");
+ if (msg->rcv.proto == PROTO_UDP)
+ LM_INFO("problem getting stored info - possible retransmission\n");
+ else
+ LM_ERR("getting stored info\n");
goto error;
}
reason= subs.reason;
@@ -885,9 +888,26 @@ error:
if(sent_reply== 0)
{
- if(send_error_reply(msg, reply_code, reply_str)< 0)
+ if (reply_code == 200)
{
- LM_ERR("failed to send reply on error case\n");
+ if(subs.event->type & PUBL_TYPE)
+ {
+ if(send_2XX_reply(msg, 202, subs.expires,
+ &subs.local_contact) <0)
+ LM_ERR("failed to send reply on error case\n");
+ }
+ else
+ {
+ /* For presence.winfo */
+ if(send_2XX_reply(msg, 200, subs.expires,
+ &subs.local_contact) <0)
+ LM_ERR("failed to send reply on error case\n");
+ }
+ }
+ else
+ {
+ if(send_error_reply(msg, reply_code, reply_str)< 0)
+ LM_ERR("failed to send reply on error case\n");
}
}
@@ -1082,21 +1102,21 @@ int extract_sdialog_info(subs_t* subs,struct sip_msg* msg, int mexp,
subs->contact.s, subs->contact.len);
if (EVENT_DIALOG_SLA(subs->event->evp))
- {
- /* user_contact@from_domain */
- if(parse_uri(subs->contact.s, subs->contact.len, &uri)< 0)
- {
- LM_ERR("failed to parse contact uri\n");
- goto error;
- }
- if(uandd_to_uri(uri.user, subs->from_domain, &subs->pres_uri)< 0)
- {
- LM_ERR("failed to construct uri\n");
- goto error;
- }
- LM_DBG("&&&&&&&&&&&&&&& dialog pres_uri= %.*s\n",subs->pres_uri.len, subs->pres_uri.s);
- }
-
+ {
+ /* user_contact@from_domain */
+ if(parse_uri(subs->contact.s, subs->contact.len, &uri)< 0)
+ {
+ LM_ERR("failed to parse contact uri\n");
+ goto error;
+ }
+ if(uandd_to_uri(uri.user, subs->from_domain, &subs->pres_uri)< 0)
+ {
+ LM_ERR("failed to construct uri\n");
+ goto error;
+ }
+ LM_DBG("&&&&&&&&&&&&&&& dialog pres_uri= %.*s\n",
+ subs->pres_uri.len, subs->pres_uri.s);
+ }
/*process record route and add it to a string*/
if(*to_tag_gen && msg->record_route!=NULL)
@@ -1152,18 +1172,17 @@ int get_stored_info(struct sip_msg* msg, subs_t* subs, int* reply_code,
unsigned int hash_code;
/* first try to_user== pres_user and to_domain== pres_domain */
-
- if(subs->pres_uri.s == NULL)
- {
- uandd_to_uri(subs->to_user, subs->to_domain, &pres_uri);
- if(pres_uri.s== NULL)
- {
- LM_ERR("creating uri from user and domain\n");
- return -1;
- }
- }
- else
- pres_uri = subs->pres_uri;
+ if(subs->pres_uri.s == NULL)
+ {
+ uandd_to_uri(subs->to_user, subs->to_domain, &pres_uri);
+ if(pres_uri.s== NULL)
+ {
+ LM_ERR("creating uri from user and domain\n");
+ return -1;
+ }
+ }
+ else
+ pres_uri = subs->pres_uri;
hash_code= core_hash(&pres_uri, &subs->event->name, shtable_size);
lock_get(&subs_htable[hash_code].lock);
@@ -1176,14 +1195,13 @@ int get_stored_info(struct sip_msg* msg, subs_t* subs, int* reply_code,
}
lock_release(&subs_htable[hash_code].lock);
- if(subs->pres_uri.s)
- goto not_found;
+ if(subs->pres_uri.s)
+ goto not_found;
- pkg_free(pres_uri.s);
+ pkg_free(pres_uri.s);
pres_uri.s= NULL;
-
- LM_DBG("record not found using R-URI search iteratively\n");
+ LM_DBG("record not found using R-URI search iteratively\n");
/* take one row at a time */
for(i= 0; i< shtable_size; i++)
{
@@ -1207,26 +1225,35 @@ int get_stored_info(struct sip_msg* msg, subs_t* subs, int* reply_code,
lock_release(&subs_htable[i].lock);
}
+not_found:
if(dbmode != DB_MEMORY_ONLY)
{
- return get_database_info(msg, subs, reply_code, reply_str);
+ return get_database_info(msg, subs, reply_code, reply_str);
}
-not_found:
-
- LM_ERR("record not found in hash_table\n");
- *reply_code= 481;
- *reply_str= pu_481_rpl;
+ if (msg->rcv.proto == PROTO_UDP && subs->expires == 0)
+ {
+ /* Assume it's a retransmission of an un-SUBSCRIBE */
+ LM_INFO("No matching subscription dialog found in database - possible retransmission of un-SUBSCRIBE?\n");
+ *reply_code= 200;
+ *reply_str= su_200_rpl;
+ }
+ else
+ {
+ /* It's definitely an error */
+ LM_ERR("record not found in hash_table\n");
+ *reply_code= 481;
+ *reply_str= pu_481_rpl;
+ }
return -1;
found_rec:
-
LM_DBG("Record found in hash_table\n");
-
+
if(!EVENT_DIALOG_SLA(s->event->evp))
subs->pres_uri= pres_uri;
-
+
subs->version = s->version;
subs->status= s->status;
if(s->reason.s && s->reason.len)
@@ -1257,14 +1284,25 @@ found_rec:
if(subs->remote_cseq<= s->remote_cseq)
{
- LM_ERR("wrong sequence number;received: %d - stored: %d\n",
- subs->remote_cseq, s->remote_cseq);
-
- *reply_code= 400;
- *reply_str= pu_400_rpl;
lock_release(&subs_htable[i].lock);
- goto error;
+ if (msg->rcv.proto == PROTO_UDP)
+ {
+ /* Assume it's a retransmission of a SUBSCRIBE */
+ LM_INFO("Possible retransmission of SUBSCRIBE?\n");
+ *reply_code= 200;
+ *reply_str= su_200_rpl;
+ return -1;
+ }
+ else
+ {
+ /* It's definitely an error */
+ LM_ERR("wrong sequence number received: %d - stored: %d\n",
+ subs->remote_cseq, s->remote_cseq);
+ *reply_code= 400;
+ *reply_str= pu_400_rpl;
+ goto error;
+ }
}
lock_release(&subs_htable[i].lock);
@@ -1282,64 +1320,20 @@ error:
int get_database_info(struct sip_msg* msg, subs_t* subs, int* reply_code, str* reply_str)
{
- db_key_t query_cols[10];
- db_val_t query_vals[10];
- db_key_t result_cols[9];
+ db_key_t query_cols[3];
+ db_val_t query_vals[3];
+ db_key_t result_cols[7];
db1_res_t *result= NULL;
db_row_t *row ;
db_val_t *row_vals ;
int n_query_cols = 0;
int n_result_cols = 0;
int remote_cseq_col= 0, local_cseq_col= 0, status_col, reason_col;
- int record_route_col, version_col;
- int pres_uri_col;
+ int record_route_col, version_col, pres_uri_col;
unsigned int remote_cseq;
str pres_uri, record_route;
str reason;
- query_cols[n_query_cols] = &str_to_user_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- query_vals[n_query_cols].val.str_val = subs->to_user;
- n_query_cols++;
-
- query_cols[n_query_cols] = &str_to_domain_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- query_vals[n_query_cols].val.str_val = subs->to_domain;
- n_query_cols++;
-
- query_cols[n_query_cols] = &str_watcher_username_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- query_vals[n_query_cols].val.str_val = subs->from_user;
- n_query_cols++;
-
- query_cols[n_query_cols] = &str_watcher_domain_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- query_vals[n_query_cols].val.str_val = subs->from_domain;
- n_query_cols++;
-
- query_cols[n_query_cols] = &str_event_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- query_vals[n_query_cols].val.str_val = subs->event->name;
- n_query_cols++;
-
- query_cols[n_query_cols] = &str_event_id_col;
- query_vals[n_query_cols].type = DB1_STR;
- query_vals[n_query_cols].nul = 0;
- if( subs->event_id.s != NULL)
- {
- query_vals[n_query_cols].val.str_val.s = subs->event_id.s;
- query_vals[n_query_cols].val.str_val.len = subs->event_id.len;
- } else {
- query_vals[n_query_cols].val.str_val.s = "";
- query_vals[n_query_cols].val.str_val.len = 0;
- }
- n_query_cols++;
-
query_cols[n_query_cols] = &str_callid_col;
query_vals[n_query_cols].type = DB1_STR;
query_vals[n_query_cols].nul = 0;
@@ -1385,29 +1379,29 @@ int get_database_info(struct sip_msg* msg, subs_t* subs, int* reply_code, str* r
if(result && result->n <=0)
{
- LM_ERR("No matching subscription dialog found in database\n");
-
pa_dbf.free_result(pa_db, result);
- *reply_code= 481;
- *reply_str= pu_481_rpl;
+
+ if (msg->rcv.proto == PROTO_UDP && subs->expires == 0)
+ {
+ /* Assume it's a retransmission of an un-SUBSCRIBE */
+ LM_INFO("No matching subscription dialog found in database - possible retransmission of un-SUBSCRIBE?\n");
+ *reply_code= 200;
+ *reply_str= su_200_rpl;
+ }
+ else
+ {
+ /* It's definitely an error */
+ LM_ERR("No matching subscription dialog found in database\n");
+ *reply_code= 481;
+ *reply_str= pu_481_rpl;
+ }
return -1;
}
row = &result->rows[0];
row_vals = ROW_VALUES(row);
- remote_cseq= row_vals[remote_cseq_col].val.int_val;
-
- if(subs->remote_cseq<= remote_cseq)
- {
- LM_ERR("wrong sequence number received: %d - stored: %d\n",
- subs->remote_cseq, remote_cseq);
- *reply_code= 400;
- *reply_str= pu_400_rpl;
- pa_dbf.free_result(pa_db, result);
- return -1;
- }
-
+
subs->status= row_vals[status_col].val.int_val;
reason.s= (char*)row_vals[reason_col].val.string_val;
if(reason.s)
@@ -1453,6 +1447,31 @@ int get_database_info(struct sip_msg* msg, subs_t* subs, int* reply_code, str* r
subs->record_route.len= record_route.len;
}
+ remote_cseq= row_vals[remote_cseq_col].val.int_val;
+ if(subs->remote_cseq<= remote_cseq)
+ {
+ pa_dbf.free_result(pa_db, result);
+
+ if (msg->rcv.proto == PROTO_UDP)
+ {
+ /* Assume it's a retransmission of a SUBSCRIBE */
+ LM_INFO("Possible retransmission of SUBSCRIBE?\n");
+ *reply_code= 200;
+ *reply_str= su_200_rpl;
+ }
+ else
+ {
+ /* It's definitely an error */
+ LM_ERR("wrong sequence number received: %d - stored: %d\n",
+ subs->remote_cseq, remote_cseq);
+ *reply_code= 400;
+ *reply_str= pu_400_rpl;
+ }
+
+ return -1;
+ }
+
+
pa_dbf.free_result(pa_db, result);
result= NULL;
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--
Peter Dunkley
Technical Director
Crocodile RCS Ltd
</PRE>
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<BR>
<PRE>
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Peter Dunkley
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Crocodile RCS Ltd
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