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

Liviu Chircu liviu at opensips.org
Wed Dec 12 11:36:48 EST 2018


Then you can just do:

...
$ru = $(hdr(Path){nameaddr.uri}{param.value,received});
...

Liviu Chircu
OpenSIPS Developer
http://www.opensips-solutions.com

On 12.12.2018 18:33, Julian Santer wrote:
> 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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