[OpenSIPS-Users] Nathelper keepalive issue with received column in usrloc

Julian Santer julian.santer at rolmail.net
Wed Dec 12 11:33:26 EST 2018


Hi Liviu,

thank you, but I have to change $ru = $(var(ct){param.value,received}); 
with $ru = $(var(ct){param.value,received}{re.subst,/>//});

My path header looks like:  <sip:IP_EDGE;lr;received=sip:IP_UAC:40885>
So param.value,received returns sip:IP_UAC:40885>
Then I have to remove the ">" sign.
If I don't remove I get <sip:IP_UAC:40885>>

Kind regards,
Julian Santer

Am 12.12.18 um 16:58 schrieb Liviu Chircu:
> Hi Julian,
> 
> Good catch on the Contact URI params - will have to remember to 
> incorporate them into the fix when the time comes for it.
> 
> You can rid OpenSIPS of all those regex substitution operations with 
> this neat "$ru exploiting" trick:
> 
>      $var(ct) = "sip:1.2.3.4;lr;received=sip:10.0.0.10:40885";
>      $var(ru_bak) = $ru;
>      $ru = $(var(ct){param.value,received});
>      $var(rcv_host) = $rd;
>      $var(rcv_port) = $rp;
>      $ru = $var(ru_bak);
> 
> Best regards,
> 
> Liviu Chircu
> OpenSIPS Developer
> http://www.opensips-solutions.com
> 
> On 12.12.2018 17:45, Julian Santer wrote:
>> Hi Liviu,
>>
>> thank you for your help.
>> Without the received header, I got some problems. The calls are being 
>> send from the core to the UAC and not to the edge server.
>>
>> So now I implemented your workaround on my lab servers:
>>
>> core:
>>     $var(rcv) = null;
>>     $var(rcv_host) = null;
>>     $var(rcv_port) = null;
>>     $var(ct_uri_params) = null;
>>
>>     xlog("L_INFO", "PATH $(hdr(Path)) - LF_BASE");
>>     if ($(hdr(Path){param.exist,received}))
>>     {
>>         $var(rcv) = $(hdr(Path){param.value,received});
>>         $var(rcv_host) = $(var(rcv){re.subst,/sip://});
>>         $var(rcv_host) = $(var(rcv_host){re.subst,/:.*//});
>>         $var(rcv_port) = $(var(rcv){re.subst,/sip:.+://});
>>         $var(rcv_port) = $(var(rcv_port){re.subst,/>//});
>>
>>         AVP_RECEIVED = "sip:" + $(ct.fields(uri){uri.user}) + "@" + 
>> $var(rcv_host) + ":" + $var(rcv_port);
>>         $var(ct_uri_params) = $(ct.fields(uri){uri.params});
>>         if ($var(ct_uri_params) != null) {
>>             AVP_RECEIVED = AVP_RECEIVED + ";" + $var(ct_uri_params);
>>         }
>>         xlog("L_INFO", "PATH received $var(rcv), host $var(rcv_host), 
>> port $var(rcv_port), AVP_RECEIVED - LF_BASE");
>>     }
>>
>>     if (src_ip == REGISTRAR_FAILOVER_IP)
>>     {
>>         if (! save("LOCATION_TABLE", "mp1"))
>>         {
>>             xlog("L_ERR", "Saving contact from REGISTRAR_FAILOVER_IP 
>> (REGISTRAR_FAILOVER) failed - LF_BASE");
>>             exit;
>>         }
>>         xlog("L_INFO", "Saving contact received from 
>> REGISTRAR_FAILOVER_IP (REGISTRAR_FAILOVER) - LF_BASE");
>>         t_on_branch("BR_DROP");
>>     }
>>     else
>>     {
>>         if (proto == UDP)
>>         {
>>             setbflag(SIP_PING_FLAG);
>>             xlog("L_INFO", "Nat keepalive sip_ping_flag - LF_BASE");
>>         }
>>
>>         if (! save("LOCATION_TABLE", "p1"))
>>         {
>>             xlog("L_ERR", "Saving contact from EDGE failed - LF_BASE");
>>             t_replicate("sip:REGISTRAR_FAILOVER", "0x04");
>>             exit;
>>         }
>>         xlog("L_INFO", "Saving contact received from EDGE, replicate 
>> to REGISTRAR_FAILOVER - LF_BASE");
>>         t_replicate("sip:REGISTRAR_FAILOVER", "0x04");
>>         t_on_branch("BR_DROP");
>>     }
>>
>> As you can see, I also needed to add the contact uri params to the 
>> received AVP. Without this params I get a 404 from the UAC.
>>
>> To be sure, if this workaround works, I have to publish it on the 
>> production server. I will do this tomorrow morning and I hope it works 
>> also with the other, undefined UAC's.
>>
>> Kind regards,
>> Julian Santer
>>
>>
>> Am 08.12.18 um 17:29 schrieb Liviu Chircu:
>>> Hi Julian,
>>>
>>> This asymmetry of the OPTIONS R-URI + To header field when pinging 
>>> either normal contacts (includes "username@" part) or NAT'ed contacts 
>>> (skips the "username@" part) actually looks like a bug -- I will look 
>>> into a fix in the background.
>>>
>>> For the time being, you should be able to circumvent the bug using 
>>> the following technique:
>>>
>>> _edge script_
>>>
>>> no need to change anything here, using add_path_received() is correct.
>>>
>>> _core script_
>>>
>>> * define the "received_avp" modparam for both registrar and nathelper 
>>> -- they must be set to the same AVP, say "$avp(rcv)"
>>> * using the script transformations [1] and/or other magic, extract 
>>> the value of the ";received=" Path header parameter into two 
>>> convenient variables: $var(rcv_host) and $var(rcv_port).
>>> * prepare the exact content of the future R-URI / To header pings for 
>>> this contact by populating $avp(rcv):
>>>
>>>      $avp(rcv) = "sip:" + $(ct.fields(uri){uri.user}) + "@" + 
>>> $var(rcv_host) + ":" + $var(rcv_port);
>>>
>>> * save("p1"); # notice we skip the "v" (Path ";received=" param) 
>>> logic, as the received URI is already set
>>>
>>> Best regards,
>>>
>>> [1]: https://www.opensips.org/Documentation/Script-Tran-2-2
>>>
>>> Liviu Chircu
>>> OpenSIPS Developer
>>> http://www.opensips-solutions.com
>>>
>>> On 20.11.2018 17:01, Julian Santer wrote:
>>>> Hi guys,
>>>>
>>>> as I see in the tcpdump:
>>>>
>>>> - with the received header the R-RURI in the INVITE looks like:
>>>>
>>>> Request-Line: INVITE sip:dev-lab1 at 192.168.44.101:40885;line=fjafxbr9 
>>>> SIP/2.0
>>>>
>>>>
>>>> - without the received header the R-URI in the INVITE looks like:
>>>>
>>>> Request-Line: INVITE sip:dev-lab1 at 212.46.162.97:40885;line=7wsv12yg 
>>>> SIP/2.0
>>>>
>>>>
>>>> Could the INVITE been rejeced/dropped by the UAC, if the R-RURI 
>>>> contains the public instead the private IP or another port etc.?
>>>>
>>>> From UAC perspective, the R-RURI (puclic IP) by incoming packets 
>>>> doesn't match the R-RURI (private IP) by outgoing packets.
>>>>
>>>>
>>>> Kind regards,
>>>>
>>>> Julian Santer
>>>>
>>>> Am 20.11.18 um 15:51 schrieb Julian Santer:
>>>>> Hi guys,
>>>>>
>>>>> if I don't use the received column on the edge server, but I call 
>>>>> fix_nated_contact instead, it seems to work.
>>>>>
>>>>> if (nat_uac_test("127"))
>>>>> {
>>>>>     fix_nated_contact();
>>>>> }
>>>>>
>>>>> consume_credentials();
>>>>>
>>>>> if (! add_path())
>>>>> {
>>>>>     send_reply("500", "Internal path error, registration not stored");
>>>>>     xlog("L_ERR", "Adding PATH (with received) failed - LF_BASE");
>>>>>     exit;
>>>>> }
>>>>>
>>>>> Is this the right way or could I break something else with this 
>>>>> change?
>>>>>
>>>>>
>>>>> Kind regards,
>>>>>
>>>>> Julian Santer
>>>>>
>>>>> Am 19.11.18 um 18:41 schrieb Julian Santer:
>>>>>> Hi guys,
>>>>>>
>>>>>> we need to switch from nat_traversal to nathelper.
>>>>>> The reason is the keepalive mechanism.
>>>>>>
>>>>>> The nat_traversal module sends OPTIONS with the following to 
>>>>>> header: sip:UAC_IP:UAC_PORT
>>>>>> Most of the UAC's answers with a 404 Not found.
>>>>>> On AVM Fritzbox with firmware >= 6.04, this OPTIONS may activate a 
>>>>>> security feature.
>>>>>> So after a certain time, the Fritzbox blocks all packages send 
>>>>>> from our proxy.
>>>>>> As we have ca. 80% AVM Fritzbox as UAC, we got a big problem.
>>>>>> So we deactivated the nat_keepalive vor this UAC's and we have to 
>>>>>> enable the keepalive Feature on the Fritzbox.
>>>>>>
>>>>>> The better solution would be, if we could send OPTIONS with a to 
>>>>>> header like: sip:username at UAC_IP:UAC_PORT.
>>>>>> As I understood the nathelper module could send OPTIONS like this. 
>>>>>> Because it is looking into the userloc table. Right?
>>>>>>
>>>>>> The nathelper module is on our edge server, the registrar on our 
>>>>>> core server.
>>>>>> For the "normal" UAC's (no received entry in usrloc) the 
>>>>>> keepalive's are now sent as expected.
>>>>>> But for the "nated" UAC's (received entry in usrloc) the 
>>>>>> keepalive's are like before: sip:UAC_IP:UAC_PORT (values in the 
>>>>>> received column from usrloc).
>>>>>> The REGISTER send to the core got the path header looking like:
>>>>>> Path: <sip:IP_EDGE;lr;received=sip:IP_UAC:40885>
>>>>>>
>>>>>> Is there a possibility to add the $fU on the received part of the 
>>>>>> path header (the user in the path module adds a string to the path 
>>>>>> part, but not to the received part)?
>>>>>> Or is there a possiblity on the registrar to store the $fU in the 
>>>>>> received column?
>>>>>> On the nathelper keepalive mechanism I don't see any possibility 
>>>>>> to add the $fU.
>>>>>>
>>>>>> We are using the version 2.2.6 from the official debian source list.
>>>>>>
>>>>>> The config on the edge server's looks like:
>>>>>> #### nat helper module
>>>>>> loadmodule "nathelper.so"
>>>>>> modparam("nathelper", "natping_interval", 0)
>>>>>> modparam("nathelper", "ping_nated_only", 0)
>>>>>> modparam("nathelper", "natping_partitions", 1)
>>>>>> modparam("nathelper", "natping_tcp", 0)
>>>>>>
>>>>>> ### REGISTER
>>>>>>
>>>>>> $var(nat) = null;
>>>>>>
>>>>>> if (nat_uac_test("127"))
>>>>>> {
>>>>>>     $var(nat) = TRUE;
>>>>>> }
>>>>>> else
>>>>>> {
>>>>>>     $var(nat) = FALSE;
>>>>>> }
>>>>>>
>>>>>> consume_credentials();
>>>>>>
>>>>>> if ($var(nat) == TRUE)
>>>>>> {
>>>>>>     if (! add_path_received())
>>>>>>     {
>>>>>>         xlog("L_ERR", "Adding PATH (with received) failed - 
>>>>>> LF_BASE");
>>>>>>         send_reply("500", "Internal path error, registration not 
>>>>>> stored");
>>>>>>         exit;
>>>>>>     }
>>>>>> }
>>>>>> else
>>>>>> {
>>>>>>     if (! add_path())
>>>>>>     {
>>>>>>         send_reply("500", "Internal path error, registration not 
>>>>>> stored");
>>>>>>         xlog("L_ERR", "Adding PATH (with received) failed - 
>>>>>> LF_BASE");
>>>>>>         exit;
>>>>>>     }
>>>>>> }
>>>>>>
>>>>>> route("R_RELAY_TO_REGISTRAR");
>>>>>> exit;
>>>>>>
>>>>>> ### OPTIONS
>>>>>>
>>>>>> if (method=="OPTIONS")
>>>>>> {
>>>>>>     if ($si == "CORE")
>>>>>>     {
>>>>>>         topology_hiding("U");
>>>>>>         if (! t_relay("0x05"))
>>>>>>         {
>>>>>>             send_reply("500", "Internal server error - failed to 
>>>>>> relay");
>>>>>>             xlog("L_ERR", "Unable to relay OPTIONS - LF_BASE");
>>>>>>         }
>>>>>>     }
>>>>>> }
>>>>>>
>>>>>>
>>>>>> The config on the core server looks like:
>>>>>> loadmodule "usrloc.so"
>>>>>> modparam("usrloc", "user_column",           "username")
>>>>>> modparam("usrloc", "domain_column",         "domain")
>>>>>> modparam("usrloc", "contact_column",        "contact")
>>>>>> modparam("usrloc", "expires_column",        "expires")
>>>>>> modparam("usrloc", "q_column",              "q")
>>>>>> modparam("usrloc", "callid_column",         "callid")
>>>>>> modparam("usrloc", "cseq_column",           "cseq")
>>>>>> modparam("usrloc", "methods_column",        "methods")
>>>>>> modparam("usrloc", "flags_column",          "flags")
>>>>>> modparam("usrloc", "user_agent_column",     "user_agent")
>>>>>> modparam("usrloc", "received_column",       "received")
>>>>>> modparam("usrloc", "path_column",           "path")
>>>>>> modparam("usrloc", "socket_column",         "socket")
>>>>>> modparam("usrloc", "use_domain",            0)
>>>>>> modparam("usrloc", "desc_time_order",       0)
>>>>>> modparam("usrloc", "timer_interval",        60)
>>>>>> modparam("usrloc", "db_url",                "DBURL")
>>>>>> modparam("usrloc", "db_mode",               2)
>>>>>> modparam("usrloc", "matching_mode",         0)
>>>>>> modparam("usrloc", "cseq_delay",            20)
>>>>>> modparam("usrloc", "nat_bflag",             6)
>>>>>>
>>>>>> #### nat helper module
>>>>>> loadmodule "nathelper.so"
>>>>>> modparam("nathelper", "natping_interval", 56)
>>>>>> modparam("nathelper", "ping_nated_only", 0)
>>>>>> modparam("nathelper", "natping_partitions", 1)
>>>>>> modparam("nathelper", "sipping_bflag", 8)
>>>>>> modparam("nathelper", "sipping_from", "sip:keepalive at DEFAULT_REALM")
>>>>>> modparam("nathelper", "sipping_method", "OPTIONS")
>>>>>>
>>>>>> # We want to send a keepalive on each registered UAC
>>>>>> if (proto == UDP)
>>>>>> {
>>>>>>     setbflag(8);
>>>>>>     xlog("L_INFO", "Nat keepalive sip_ping_flag - LF_BASE");
>>>>>> }
>>>>>>
>>>>>> if (! save("location", "vp1"))
>>>>>> {
>>>>>>     xlog("L_ERR", "Saving contact from EDGE failed - LF_BASE");
>>>>>>     exit;
>>>>>> }
>>>>>>
>>>>>> Thank you for any hint.
>>>>>>
>>>>>> Kind regards,
>>>>>> Julian Santer
>>>>>> Raiffeisen OnLine
>>>>>>
>>>>>> ps: @Bogdan: this is why we have ca. 550 entry's in the address 
>>>>>> table (permission module). If we solve the keepalives, only ca. 50 
>>>>>> entry's are remaining.
>>>>
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>>
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