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### Description

When using the PATH header option to keep track of original Kamailio node that received the REGISTER, if nathelper is also used with SIP ping enabled, the SIP OPTIONS is sent to itself following the PATH header and not sent directly to the destination. The nathelper/user location modules should have a flag similar to the "path_check_local" of the registrar module, which is meant to avoid looping the message to itself in case the next hop pointed by the PATH header is "myself". <!-- Explain what you did, what you expected to happen, and what actually happened. -->

### Troubleshooting

#### Reproduction Configure the registrar module to support PATH and before saving the contact info add the PATH header with the local Kamailio information. Also make sure to have the nathelper and usrloc modules configured to send the keepalive SIP OPTIONS to the registered extensions. By the time the SIP OPTIONS is sent, Kamailio sends to itself, then the message has to be loose_route'd to the final destination. This could be avoided by having the nathelper module to identify the next hop is Kamailio itself skipping this destination as a call to "lookup()" does for the registrar module when the flag path_check_local is true. <!-- If the issue can be reproduced, describe how it can be done. -->

#### SIP Traffic

<!-- If the issue is exposed by processing specific SIP messages, grab them with ngrep or save in a pcap file, then add them next, or attach to issue, or provide a link to download them (e.g., to a pastebin site). --> 172.128.128.10 is the Kamailio IP and 172.128.128.20 is the extension IP ``` 11:51:07.224713 IP (tos 0x60, ttl 64, id 64497, offset 0, flags [none], proto UDP (17), length 518) 172.128.128.10.5060 > 172.128.128.10.5060: SIP, length: 490 OPTIONS sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP SIP/2.0 Via: SIP/2.0/UDP 172.128.128.10:5060;branch=z9hG4bK2540713 Route: sip:172.128.128.10:5060;received=sip:172.128.128.20:5060;lr;cluster_node=192.168.156.10:5060 From: sip:sbc@mydomain.com;tag=uloc-5d2e6499-2fb5-1-0-c15309d2 To: sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP Call-ID: 40ee1573-7506bba3-5e30c05@172.128.128.10 CSeq: 1 OPTIONS Content-Length: 0 11:51:07.226132 IP (tos 0x60, ttl 64, id 44359, offset 0, flags [none], proto UDP (17), length 502) 172.128.128.10.5060 > 172.128.128.20.5060: SIP, length: 474 OPTIONS sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP SIP/2.0 Via: SIP/2.0/UDP 172.128.128.10;branch=z9hG4bKb958.b807e80b742db62504a45220d8f0e974.0 Via: SIP/2.0/UDP 172.128.128.10:5060;branch=z9hG4bK2540713 From: sip:sbc@mydomain.com;tag=uloc-5d2e6499-2fb5-1-0-c15309d2 To: sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP Call-ID: 40ee1573-7506bba3-5e30c05@172.128.128.10 CSeq: 1 OPTIONS Content-Length: 0 11:51:07.303474 IP (tos 0x0, ttl 128, id 10816, offset 0, flags [none], proto UDP (17), length 786) 172.128.128.20.5060 > 172.128.128.10.5060: SIP, length: 758 SIP/2.0 200 OK Via: SIP/2.0/UDP 172.128.128.10;branch=z9hG4bKb958.b807e80b742db62504a45220d8f0e974.0 Via: SIP/2.0/UDP 172.128.128.10:5060;branch=z9hG4bK2540713 Contact: sip:172.128.128.20:5060 To: sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP;tag=bb0c1f2d From: sip:sbc@mydomain.com;tag=uloc-5d2e6499-2fb5-1-0-c15309d2 Call-ID: 40ee1573-7506bba3-5e30c05@172.128.128.10 CSeq: 1 OPTIONS Accept: application/sdp, application/sdp Accept-Language: en Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS, INFO, SUBSCRIBE Supported: replaces, norefersub, extended-refer, timer, outbound, path, X-cisco-serviceuri User-Agent: Z 3.15.40006 rv2.8.20 Allow-Events: presence, kpml, talk Content-Length: 0 11:51:07.306821 IP (tos 0x60, ttl 64, id 64570, offset 0, flags [none], proto UDP (17), length 727) 172.128.128.10.5060 > 172.128.128.10.5060: SIP, length: 699 SIP/2.0 200 OK Via: SIP/2.0/UDP 172.128.128.10:5060;branch=z9hG4bK2540713 Contact: sip:172.128.128.20:5060;alias=172.128.128.20~5060~1 To: sip:345671002@172.128.128.20:5060;rinstance=d1eb3444a5cec5a1;transport=UDP;tag=bb0c1f2d From: sip:sbc@mydomain.com;tag=uloc-5d2e6499-2fb5-1-0-c15309d2 Call-ID: 40ee1573-7506bba3-5e30c05@172.128.128.10 CSeq: 1 OPTIONS Accept: application/sdp, application/sdp Accept-Language: en Allow: INVITE, ACK, CANCEL, BYE, NOTIFY, REFER, MESSAGE, OPTIONS, INFO, SUBSCRIBE Supported: replaces, norefersub, extended-refer, timer, outbound, path, X-cisco-serviceuri User-Agent: Z 3.15.40006 rv2.8.20 Allow-Events: presence, kpml, talk Content-Length: 0 ```

### Possible Solutions

<!-- If you found a solution or workaround for the issue, describe it. Ideally, provide a pull request with a fix. --> Not found.

### Additional Information

* **Kamailio Version** - output of `kamailio -v`

``` # kamailio -v version: kamailio 5.2.2 (x86_64/linux) 67f967 flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144 MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: 67f967 compiled on 11:40:41 Mar 11 2019 with gcc 4.8.5 ```

* **Operating System**:

<!-- Details about the operating system, the type: Linux (e.g.,: Debian 8.4, Ubuntu 16.04, CentOS 7.1, ...), MacOS, xBSD, Solaris, ...; Kernel details (output of `uname -a`) -->

``` # uname -a Linux kamailio-1 3.10.0-514.21.2.el7.x86_64 #1 SMP Tue Jun 20 12:24:47 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux ```