September 2008 - sr-users

[Serusers] Digest Authentication with Tenor DX
by Ashutosh Kumar 29 Apr '25

29 Apr '25

Hi, Does someone have any idea/experience with Quintum DX radius server's support for digest mode authentication. The Access-Request packets sent by SER are getting an error back. Guide. Regards, Ashutosh Kumar Chetu, Inc. Ph : 1(305) 402 6724 - Witin US Ph : 91 120 5323340 - Outside US Fax:1 (305) 832 5987 For more information, please visit http://www.chetu.com

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[OpenSER-Users] uaCSTA support in openser
by Hugo Koblmueller 09 Feb '11

09 Feb '11

high.all! i'm wondering if there is any support of uaCSTA in openser (planned)? i'm just working on the integration of asterisk (*) environment to OCS 2007 environment, having openSER in the middle (mainly for TCP/UDP translation and smoothing out the protocol deficienes on both sides). in this setup the * having the openSER in front is talking to the OCS (and vice versa) via the OCS mediation server, which is moreorless sending standard SIP messages, which enables normal softphone (integration to *) of the office communicator. this configuration is already working... now i'm planning to go for the CTI integration, where there is no OCS mediation server in between OCS and openSER, doing the translation of SIP/CSTA to SIP. i'm thinking about using openSER for this task, that's why i'm looking for a CSTA module or perl programm, which is capable of this functionality. afaik for the CTI communication there isn't the full complexity of CSTA needed, just a subset mainly for call setup and call clearing. anyone having experience on this topic? thx & cheers -hugo Great Ideas for Small Devices Hugo Koblmueller Senior Staff Engineer Software Development COMNEON electronic technology GmbH & Co. OHG Freistaedter Strasse 400 4040 Linz Austria hugo.koblmueller(a)comneon.com tel: fax: mobile: Skype ID: +43 (5) 1777 - 15730 <http://www.plaxo.com/click_to_call?lang=en&src=jj_signature&To=%2B43+%285%2 9+1777+%2D+15730&Email=hugo(a)koblmueller.com> +43 (5) 1777 - 15810 +43 (676) 82051280 <http://www.plaxo.com/click_to_call?lang=en&src=jj_signature&To=%2B43+%28676 %29+82051280&Email=hugo(a)koblmueller.com> drhookson Want to always have my latest info? <https://www.plaxo.com/add_me?u=21475050628&src=client_sig_212_1_banner_join &invite=1&lang=en> Want a signature like <http://www.plaxo.com/signature?src=client_sig_212_1_banner_sig&lang=en> this?

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[Serusers] Deadly embrace with rtpproxy - Is it necessary? Can it be turned off?
by Frank Durda IV 20 Mar '09

20 Mar '09

I'm running into a problem with rtpproxy on this point, quoting from the README: - - - - - - - - - - - - after the session has been created, the proxy listens on the port it has allocated for that session and waits for receiving at least one UDP packet from each of two parties participating in the call. Once such packet is received, the proxy fills one of two ip:port structures associated with each call with source ip:port of that packet. When both structures are filled in, the proxy starts relaying UDP packets between parties; - - - - - - - - - - - However, a number of clients frequently fail to emit any audio when originating a call until they hear something from the TDM gateway, such as ring-back or the called party answering. So although rtpproxy is receiving a stream of audio, such as a voice mail menu robot, the calling party can't hear any of it unless they happen to make some noise or randomly and blindly press a DTMF key. This seems to be made worse on links with silence suppression, so there is no background noise to trigger two-way audio. This is being encountered between Class 4 carriers, so we don't have the option to get someone to adjust their phone/PBX settings or have them breathe heavier. Is there a setting adjustment to get rtpproxy to just pass the RTP packets from directed calling and called sources even if one party hasn't happened to make noise yet? I personally don't understand why this requirement for seeing audio from both sides before starting the flow in either direction if audio starts coming in even exists. It seems to have no benefit but is bound to cause this deadly embrace problem in many situations that may be beyond the control of the owners of the equipment passing traffic along to the site where rtpproxy is in use. Suggestions? Fix? I have looked at the latest snapshot of rtpproxy and the README is unchanged since 1.1 so apparently this behavior is still the same. Thanks in advance!

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[OpenSER-Users] [OT] How to handle different DID's in incoming calls for a registered client?
by Iñaki Baz Castillo 27 Feb '09

27 Feb '09

Hi, maybe this question is a bit off-topic so I'm sorry for that. My question is about SIP providers using OpenSer that associate PSTN numbers to their local clients (SIP accounts): Usually the client must register to OpenSer in order to receive calls. Then it will appear in location table with "Contact=sip:clientX@IP". Suppose clientX has two PSTN numbers associated in a ENUM entry: +34999000111 +34999000222 When anyone in PSTN world calls to +34999000222 the call will arrive to the OpenSer from a gateway in an INVITE like: INVITE sip:+34999000222@gateway SIP/2.0 To: <sip:+34999000222@gateway> The OpenSer will do the lookup in location table and finally send this INVITE to the clientX: INVITE sip:clientX@IP_clientX SIP/2.0 To: <sip:+34999000222@gateway> The info about the called PSTN number is just available in "To" header, so a way to get different behaviour for each associated PSTN number is matching "To" URI. Is common to do it? which other alternatives are there? Thanks for any comment. Regards. -- Iñaki Baz Castillo ibc(a)in.ilimit.es

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[OpenSER-Users] Openser1.3.2 + snmp
by Ricardo Alves Ferreira Silva 30 Oct '08

30 Oct '08

Hi all, Trying to install Openser1.3.2.... everything is OK and fine... but when I try to add support for snmp there are errors.. Dig dep into google, recheck all dependencies and didn't succeed... My env is FreeBSD 7.0-STABLE i386 The full net-snmp package is installed: atila# pkg_info | grep net-snmp net-snmp-5.3.2_3 An extendable SNMP implementation These are the error messages.... make modules/libsnmpstats modules.... Compiling alarm_checks.c gcc -fPIC -DPIC -g -O9 -funroll-loops -Wcast-align -Wall -minline-all-stringops -falign-loops -ftree-vectorize -mtune=prescott -Wold-style-definition -Wmissing-field-initializers -DMOD_NAME='"snmpstats"' -DNAME='"openser"' -DVERSION='"1.3.2-notls"' -DARCH='"i386"' -DOS='"freebsd"' -DCOMPILER='"gcc 4.2.1"' -D__CPU_i386 -D__OS_freebsd -D__SMP_no -DCFG_DIR='"/usr/local/etc/openser/"' -DPKG_MALLOC -DSHM_MEM -DSHM_MMAP -DUSE_IPV6 -DUSE_MCAST -DUSE_TCP -DDISABLE_NAGLE -DHAVE_RESOLV_RES -DSTATISTICS -DCHANGEABLE_DEBUG_LEVEL -DF_MALLOC -DFAST_LOCK -DADAPTIVE_WAIT -DADAPTIVE_WAIT_LOOPS=1024 -DHAVE_SOCKADDR_SA_LEN -DHAVE_GETHOSTBYNAME2 -DHAVE_UNION_SEMUN -DHAVE_SCHED_YIELD -DHAVE_MSGHDR_MSG_CONTROL -DHAVE_CONNECT_ECONNRESET_BUG -DHAVE_TIMEGM -DHAVE_NETINET_IN_SYSTM -DHAVE_KQUEUE -DHAVE_SELECT -c alarm_checks.c -o alarm_checks.o In file included from alarm_checks.c:38: openserObjects.h:41:38: error: net-snmp/net-snmp-config.h: No such file or directory openserObjects.h:42:40: error: net-snmp/net-snmp-includes.h: No such file or directory openserObjects.h:43:52: error: net-snmp/agent/net-snmp-agent-includes.h: No such file or directory If I edit each file and hardcode the path ... /usr/local/include/net-snmp/... there are no errors... What am I missing in making sure the path to the include files are OK... Tried a couple options but didn't succeed... tehre are tons of include files into the src.... Regards Ricardo Ferreira Yes, we do run Openser www.vipway.com.br Enterprise VoIP Services

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[Kamailio-Users] Send MaxCallDuration and UserCredit for freeradius-cdrtool
by Diego Zuaneti Arruda 20 Oct '08

20 Oct '08

Hi all, How I send to freeradius-cdrtool the maxCallDuration and UserCredit? On the /etc/raddb/users I have: 87001(a)mydomain.com.br Auth-Type := Digest, User-Password == "mypassword" Reply-Message = "Authenticated", SIP-AVP = "authentic#1", SIP-AVP = "callMaxDur:60", SIP-AVP = "credit:25" Is this correct ? Thanks. Diego.

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[Kamailio-Users] CDRTool 6.6.4 with freeradius-cdrtool
by Diego Zuaneti Arruda 15 Oct '08

15 Oct '08

Hi all, Someone has a patch for use freeradius-cdrtool with the latest version of cdrtool ? The stable versions of cdrtool not have multiple commands that were in earlier versions. Thanks. Diego.

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[Serusers] ser-0.9.6: modules/postgres bugreport & patch
by Alexandre Snarskii 13 Oct '08

13 Oct '08

Hi! I'm running ser-0.9.6, on FreeBSD 6.1-stable, database backend is postgresql version 8.1.3. Today I got errors in logfiles, saying: messages.2.bz2:May 29 14:35:03 <XXX> /usr/local/sbin/ser[51448]: ERROR:avpops:dbrow2avp: dbrow contains NULL fields The similar problem reported in: http://lists.iptel.org/pipermail/serusers/2005-May/019681.html with much more detailed description of error, database contents and config samples. Patch is trivial, and looks more like a fix to copy'n'paste error: in mysql/val.c function str2val states: if (!_s) { memset(_v, 0, sizeof(db_val_t)); VAL_TYPE(_v) = _t; VAL_NULL(_v) = 1; return 0; } VAL_NULL(_v) = 0; and the last line mentions that 'well, that's value is not NULL'. In postgresql/db_val.c, line 182, function str2valp, the same statement is the: if (!_s) { DLOG("str2valp", "got a null value"); VAL_TYPE(_v) = _t; VAL_NULL(_v) = 1; return 0; } without explicit notification that this is not-NULL value. More than, nowhere else in this function VAL_NULL(_v) not set to 0. So, if a value _v.val contained anyting but 0 at the function start, resulting value will be threated as NULL despite the fact, that _s is NOT NULL. Patch is obvious, just add VAL_NULL(_v)=0; after cited block (line 188) and everyting will be ok. At least for me it's ok for some hours :)

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[Kamailio-Users] Can openser.cfg lead to pkg memory problem?
by mayamatakeshi 07 Oct '08

07 Oct '08

Hello, we have openser 1.3.3 running in production (current rev.: 4943). For 3 times in 50 days we had to restart openser to correct pkg memory problem. After some time logging messages like this: /openser.log:Aug 19 10:39:18 ipx022 /usr/local/sbin/openser[16991]: ERROR:core:new_credentials: no pkg memory left, openser will eventually run out of pkg memory and refuse all subsequent requests. We are trying to recreate this in our lab so that we can follow memory troubleshooting instructions at http://kamailio.net/dokuwiki/doku.php/troubleshooting:memory, but so far we were unable to do it even when generating millions of calls and registration transactions (we are using SIPp to generate normal call flows and even abnormal call flows detected when reading openser.log, like 'invalid cseq for aor', malformed SIP messages etc). And this is much more than in our production environment, with just 600 subscribers and about 2000 calls a day. The frequency the problem happens is increasing with the number of subscribers, so we are performing periodic restart of openser (actually, what we do is to switch over to the standby server). We already recompiled openser with pkg memory pool size set to 4MB so that this will not have to be done frequently. Since we cannot recreate this in our lab, we suspect there is a situation happening in production that might not be having been properly handled by openser.cfg. So my question is: would it be possible to an overlooked detail in openser.cfg to cause pkg memory problem? In case someone could take a look at it, here's our cfg file: ####### Global Parameters ######### debug=0 log_stderror=no log_facility=LOG_LOCAL0 fork=yes children=4 /* uncomment the following lines to enable debugging */ #debug=6 #fork=no #log_stderror=yes /* uncomment the next line to disable TCP (default on) */ disable_tcp=yes /* uncomment the next line to enable the auto temporary blacklisting of not available destinations (default disabled) */ #disable_dns_blacklist=no /* uncomment the next line to enable IPv6 lookup after IPv4 dns lookup failures (default disabled) */ #dns_try_ipv6=yes /* uncomment the next line to disable the auto discovery of local aliases based on revers DNS on IPs (default on) */ #auto_aliases=no /* uncomment the following lines to enable TLS support (default off) */ #disable_tls = no #listen = tls:your_IP:5061 #tls_verify_server = 1 #tls_verify_client = 1 #tls_require_client_certificate = 0 #tls_method = TLSv1 #tls_certificate = "/usr/local/etc/openser/tls/user/user-cert.pem" #tls_private_key = "/usr/local/etc/openser/tls/user/user-privkey.pem" #tls_ca_list = "/usr/local/etc/openser/tls/user/user-calist.pem" port=5060 /* uncomment and configure the following line if you want openser to bind on a specific interface/port/proto (default bind on all available) */ #listen=udp:202.173.5.181:5060 ####### Modules Section ######## #set module path mpath="/usr/local/lib/openser/modules/" /* uncomment next line for MySQL DB support */ loadmodule "mysql.so" loadmodule "sl.so" loadmodule "tm.so" loadmodule "rr.so" loadmodule "maxfwd.so" loadmodule "usrloc.so" loadmodule "registrar.so" loadmodule "textops.so" loadmodule "mi_fifo.so" loadmodule "uri_db.so" loadmodule "uri.so" loadmodule "xlog.so" loadmodule "acc.so" loadmodule "carrierroute.so" loadmodule "nathelper.so" loadmodule "dialog.so" loadmodule "snmpstats.so" /* uncomment next lines for MySQL based authentication support NOTE: a DB (like mysql) module must be also loaded */ loadmodule "auth.so" loadmodule "auth_db.so" loadmodule "lcr.so" /* uncomment next line for aliases support NOTE: a DB (like mysql) module must be also loaded */ loadmodule "alias_db.so" /* uncomment next line for multi-domain support NOTE: a DB (like mysql) module must be also loaded NOTE: be sure and enable multi-domain support in all used modules (see "multi-module params" section ) */ loadmodule "domain.so" /* uncomment the next two lines for presence server support NOTE: a DB (like mysql) module must be also loaded */ #loadmodule "presence.so" #loadmodule "presence_xml.so" loadmodule "uac.so" loadmodule "avpops.so" # ----------------- setting module-specific parameters --------------- # ----- mi_fifo params ----- modparam("mi_fifo", "fifo_name", "/tmp/openser_fifo") # ----- rr params ----- # add value to ;lr param to cope with most of the UAs modparam("rr", "enable_full_lr", 1) # do not append from tag to the RR (no need for this script) modparam("rr", "append_fromtag", 1) # ----- rr params ----- modparam("registrar", "method_filtering", 1) /* uncomment the next line to disable parallel forking via location */ # modparam("registrar", "append_branches", 0) /* uncomment the next line not to allow more than 10 contacts per AOR */ modparam("registrar", "max_contacts", 10) modparam("registrar", "min_expires", 30) modparam("registrar", "max_expires", 40) modparam("registrar", "default_expires", 35) # ----- uri_db params ----- /* by default we disable the DB support in the module as we do not need it in this configuration */ modparam("uri_db", "use_uri_table", 0) modparam("uri_db", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("uri_db", "use_domain", 1) # ----- acc params ----- /* what sepcial events should be accounted ? */ modparam("acc", "early_media", 1) modparam("acc", "report_ack", 1) modparam("acc", "report_cancels", 1) /* by default ww do not adjust the direct of the sequential requests. if you enable this parameter, be sure the enable "append_fromtag" in "rr" module */ modparam("acc", "detect_direction", 0) /* account triggers (flags) */ modparam("acc", "failed_transaction_flag", 3) modparam("acc", "log_flag", 1) modparam("acc", "log_missed_flag", 2) /* uncomment the following lines to enable DB accounting also */ modparam("acc", "db_flag", 1) modparam("acc", "db_missed_flag", 2) # ----- usrloc params ----- #modparam("usrloc", "db_mode", 0) /* uncomment the following lines if you want to enable DB persistency for location entries */ modparam("usrloc", "db_mode", 2) modparam("usrloc", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("usrloc", "use_domain", 1) # ----- auth_db params ----- /* uncomment the following lines if you want to enable the DB based authentication */ modparam("auth_db", "calculate_ha1", yes) modparam("auth_db", "password_column", "password") modparam("auth_db", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("auth_db", "load_credentials", "$avp(s:rpid)=rpid;$avp(s:blocked)=subscriber_status") # ----- alias_db params ----- /* uncomment the following lines if you want to enable the DB based aliases */ modparam("alias_db", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("alias_db", "use_domain", 0) # ----- domain params ----- /* uncomment the following lines to enable multi-domain detection support */ modparam("domain", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("domain", "db_mode", 1) # Use caching # ----- multi-module params ----- /* uncomment the following line if you want to enable multi-domain support in the modules (dafault off) */ #modparam("alias_db|auth_db|usrloc|uri_db", "use_domain", 1) # ----- presence params ----- /* uncomment the following lines if you want to enable presence */ #modparam("presence|presence_xml", "db_url", # "mysql://openser:openserrw@localhost/openser") #modparam("presence_xml", "force_active", 1) #modparam("presence", "server_address", "sip:192.168.1.2:5060") # ----- carrieroute params ----- modparam("carrierroute", "db_url", "mysql://openser:openserrw@localhost /openser") modparam("carrierroute", "config_source", "db") modparam("carrierroute", "use_domain", 1) # ----- NatHelper ----- #para versao a partir da versao 1.2 eh necessario esse paramtro para nao dar erro qdo usa a funcao "fix_nated_register();" modparam("nathelper|registrar", "received_avp", "$avp(i:42)") modparam("nathelper", "rtpproxy_sock", "udp:127.0.0.1:22222") # ----- LCR ----- modparam("lcr", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("lcr|tm", "fr_inv_timer_avp", "$avp(i:704)") modparam("lcr", "gw_uri_avp", "$avp(i:709)") modparam("^auth$|lcr", "rpid_avp", "$avp(i:302)") modparam("lcr", "contact_avp", "$avp(i:711)") modparam("lcr", "ruri_user_avp", "$avp(i:500)") modparam("lcr", "dm_flag", 25) # ----- Dialog ---- modparam("dialog", "dlg_flag", 4) # ----- SnmpStat ----- modparam("snmpstats", "sipEntityType", "registrarServer") modparam("snmpstats", "sipEntityType", "proxyServer") modparam("snmpstats", "MsgQueueMinorThreshold", 2000) modparam("snmpstats", "MsgQueueMajorThreshold", 5000) modparam("snmpstats", "dlg_minor_threshold", 500) modparam("snmpstats", "dlg_major_threshold", 750) modparam("snmpstats", "snmpgetPath","/usr/bin/") modparam("snmpstats", "snmpCommunity","public") ####### Routing Logic ######## # main request routing logic route{ if (!mf_process_maxfwd_header("10")) { sl_send_reply("483","Too Many Hops"); exit; } ##nat route(2); if (has_totag()) { # sequential request withing a dialog should # take the path determined by record-routing if (loose_route()) { if (is_method("BYE")) { setflag(1); # do accouting ... setflag(3); # ... even if the transaction fails } route(1); } else { /* uncomment the following lines if you want to enable presence */ ##if (is_method("SUBSCRIBE") && $rd == "your.server.ip.address") { ## # in-dialog subscribe requests ## route(2); ## exit; ##} if ( is_method("ACK") ) { if ( t_check_trans() ) { # non loose-route, but stateful ACK; must be an ACK after a 487 or e.g. 404 from upstream server #t_relay(); #exit; route(1); } else { # ACK without matching transaction ... ignore and discard.\n"); exit; } } sl_send_reply("404","Not here"); } exit; } #initial requests setflag(4); #for dialog statistics # CANCEL processing if (is_method("CANCEL")) { if (t_check_trans()) route(1); # t_relay(); # exit; } #t_check_trans(); if (is_method("PUBLISH|SUBSCRIBE|REFER|OPTIONS|MESSAGE")) { sl_send_reply("405", "Method not allowed"); exit; } # authenticate if from local subscriber (uncomment to enable auth) if (!(method=="REGISTER") && (!from_gw())) { if (!proxy_authorize("", "subscriber")) { proxy_challenge("", "0"); exit; } if (!check_from()) { sl_send_reply("403","Forbidden auth ID"); exit; }else if (avp_check("$avp(s:blocked)", "eq/0")) { sl_send_reply("603","Subscriber disabled"); exit; }else if (avp_check("$avp(s:blocked)", "eq/1")) { sl_send_reply("603","Subscriber with outgoing blocked"); exit; } consume_credentials(); # caller authenticated } # record routing if (!is_method("REGISTER|MESSAGE")) record_route(); # account only INVITEs if (is_method("INVITE")) { setflag(1); # do accouting } if (is_method("REGISTER")) { # authenticate the REGISTER requests (uncomment to enable auth) if (!proxy_authorize("", "subscriber")) { proxy_challenge("", "0"); exit; } if (!check_to()) { sl_send_reply("403","Forbidden auth ID"); exit; }else if (avp_check("$avp(s:blocked)", "eq/0")) { sl_send_reply("403","Subscriber disabled"); exit; } if (!save("location")) sl_reply_error(); exit; } if ($rU==NULL) { # request with no Username in RURI sl_send_reply("484","Address Incomplete"); exit; } # apply DB based aliases (uncomment to enable) ##alias_db_lookup("dbaliases"); #if the call came from a known gateway it is not authenticated and we cannot use the function check_from() if (from_gw()) { route(4); }else if (!check_from()) {#if the check_from() returns false the call is not from a subscriber route(4); } else {#it is a subscriber, route using flip domain xlog("L_INFO", "routing using carrierroute $rm to $ru\n"); if (!cr_user_rewrite_uri("$fu", "flip")) { t_newtran(); t_reply("404", "No Route"); exit; } #replaces from by it's default DID uac_replace_from("sip:$avp(s:rpid)@$fd"); } # when routing via usrloc, log the missed calls also setflag(2); route(1); } route[1] { xlog("L_INFO", "ROUTE_1 $rm to $ru\n"); if (subst_uri('/(sip:.*);nat=yes/\1/')) { setflag(6); }; if (isflagset(5)||isflagset(6)) { route(3); } if (!t_relay()) { sl_reply_error(); }; exit; } route[2] { xlog("L_INFO", "ROUTE_2 $rm to $ru\n"); if (method=="REGISTER") { fix_nated_register(); } else if (!from_gw()){ fix_nated_contact(); }; setflag(5); } route[3] { xlog("L_INFO", "ROUTE_3 $rm to $ru\n"); if (is_method("BYE|CANCEL")) { unforce_rtp_proxy(); } else if (is_method("INVITE")) { xlog("L_INFO", "FORCE RTP w/ parameter.\n"); force_rtp_proxy("r"); t_on_failure("1"); }; if (isflagset(5)) search_append('Contact:.*sip:[^>[:cntrl:]]*', ';nat=yes'); t_on_reply("1"); } route[4] { xlog("L_INFO", "uri does exist $rm to $ru \n"); if (alias_db_lookup("dbaliases")){ if (!lookup("location")) { switch ($retcode) { case -1: t_newtran(); t_reply("404", "Subscriber not online"); exit; case -2: sl_send_reply("405", "Method Not Allowed"); exit; } } }else{#check if did is blocked $rU = "(BLK)" + $rU; if (alias_db_lookup("dbaliases")){ sl_send_reply("403", "DID blocked"); exit; }else{# if it is not a valid DID nor a blocked DID tries to route it using peering domain if (!cr_rewrite_uri("peering", "call_id")) { t_newtran(); t_reply("404", "Peering Not Found"); exit; } } } } failure_route[1] { xlog("L_INFO", "FAILURE $rm to $ru\n"); if (isflagset(6)||isflagset(5)) { unforce_rtp_proxy(); } } onreply_route[1] { xlog("L_INFO", "ONREPLY_1 - Status $rs from $si $rm .\n"); if (is_method("INVITE")) { if ((isflagset(5)||isflagset(6)) && status=~"(183)|(2[0-9][0-9])") { force_rtp_proxy(); } search_append('Contact:.*sip:[^>[:cntrl:]]*', ';nat=yes'); if (!from_gw()){ #if (isflagset(6)) { xlog("L_INFO", "ONREPLY_1 - ! from gw.\n"); fix_nated_contact(); } exit; } } Regards, takeshi

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[Kamailio-Users] Dispatcher hash algorithms.
by Alex Balashov 06 Oct '08

06 Oct '08

I am curious, what exactly is the purpose and philosophy of the various hash algorithms in the dispatcher module? I am referring to the ones that allow the gateway in the route set to be determined through a hash of various SIP headers, such as the From URI, the To URI, the Call-ID GUID, etc. No guarantee of fair distribution - or in fact, any distribution that can be characterised by any describable pattern whatsoever - is implied by these algorithms. Additionally, it seems that without knowing (1) The exact hash algorithm in use; (2) The distribution that this hash algorithm would yield for a given set of possible values of these header fields, which in many cases are specifically intended to be pseudorandom (e.g. Call-ID), there is absolutely no way to determine, from any meaningfully deterministic perspective, which numerical entry in the route set these algorithms would computationally yield. So, I guess my question is: With no implied uniformity or weighting in the distribution whatsoever based on the incidental character of such values, what practical use does it serve to use any algorithms except round-robin or random? Is it expected that the user will plot the hash values against a log of given input strings to determine how the distribution will shape up? Is there some reason why the sort of profoundly lopsided distribution that may create might be desirable? Thanks, -- Alex Balashov Evariste Systems Web : http://www.evaristesys.com/ Tel : (+1) (678) 954-0670 Direct : (+1) (678) 954-0671 Mobile : (+1) (706) 338-8599

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