### Description
A certain inbound provider does not return ACK R-URI as an exact copy of contact. A parameter is appended to it, like below:
200 OK Contact:
`Contact: sip:35.197.205.XXX:5060;line=sr-N6IAzJd4WxFLWxVlz.jwWB0yM.y7MlV7zGZlMlvuMx3A`
ACK R-URI:
`ACK sip:35.197.205.XXX:5060;line=sr-N6IAzJd4WxFLWxVlz.jwWB0yM.y7MlV7zGZlMlvuMx3A;user=phone SIP/2.0`
As you can see, the `user=phone` is appended along with `line=` put by topoh.
### Troubleshooting
#### Reproduction
I am not sure how this can be reproductible. I've put the URI with and without `user=phone` part in a small C app that calls kamailio's `parse_params` function and both resolved to one and two params, as expected, so the problem must come from `parse_uri`. See the debug logs below that show the difference between a "good" ACK and a "bad" ACK. `topoh` doesn't get its `line=` param, so it doesn't perform the `Contact` header rewrite. The ACK does not match a dialog/transaction and it is forwarded to itself (from internal IP to external IP, this being a kamailio behind NAT, but that's not the problem).
#### Debugging Data
#### Log Messages
This is the "good" call, with ACK R-URI identical to Contact header. See the "+decoded" line:
``` 13(40) DEBUG: topoh [topoh_mod.c:249]: th_prepare_msg(): no second via in this message 13(40) DEBUG: <core> [core/parser/parse_addr_spec.c:185]: parse_to_param(): add param: tag=as496aacd0 13(40) DEBUG: <core> [core/parser/parse_addr_spec.c:864]: parse_addr_spec(): end of header reached, state=29 13(40) DEBUG: topoh [th_msg.c:1165]: th_route_direction(): ftag match 13(40) DEBUG: topoh [th_msg.c:763]: th_unmask_ruri(): +decoded: 34: [sip:+441274957XXX@10.32.2.133:5060] 13(40) DEBUG: topoh [topoh_mod.c:358]: th_msg_received(): adding cookie: dc 13(40) DEBUG: topoh [th_msg.c:997]: th_add_hdr_cookie(): added cookie header [TH: dch ```
This is the "bad" call, with ACK R-URI having a `user=phone` param appended to original Contact contents:
``` 10(37) DEBUG: topoh [topoh_mod.c:249]: th_prepare_msg(): no second via in this message 10(37) DEBUG: <core> [core/parser/parse_addr_spec.c:185]: parse_to_param(): add param: tag=3735986184-753647 10(37) DEBUG: <core> [core/parser/parse_addr_spec.c:864]: parse_addr_spec(): end of header reached, state=29 10(37) DEBUG: topoh [th_msg.c:1165]: th_route_direction(): ftag match 10(37) DEBUG: <core> [core/parser/parse_param.c:580]: parse_params2(): empty uri params, skipping 10(37) DEBUG: topoh [topoh_mod.c:358]: th_msg_received(): adding cookie: dc 10(37) DEBUG: topoh [th_msg.c:997]: th_add_hdr_cookie(): added cookie header [TH: dch ```
#### SIP Traffic
``` U 2018/05/21 10:22:53.206320 35.197.205.XXX:5060 -> 88.215.58.YYY:5060 SIP/2.0 200 OK. Via: SIP/2.0/UDP 88.215.58.YYY:5060;rport=5060;branch=z9hG4bK469d20c71c138e366475cd537dc0c68b. Record-Route: sip:35.197.205.XXX;lr;ftag=3735908572-610467;vsf=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7dXNlcj1waG9uZQ--;vst=AAAAAAAAAAAAAAAAAAAAAAAACQgAAQMbFhsLHTE1OjUwNjA7dXNlcj1waG9uZQ--;did=f17.b7f. From: sip:+16098378XXX@88.215.58.YYY;user=phone;tag=3735908572-610467. To: sip:+441242395XXX@88.215.58.YYY:5060;user=phone;tag=as3147fc45. Call-ID: 5577511-3735908572-610459@MSX163.XXX.com. CSeq: 1 INVITE. Server: Asterisk PBX 1.8.28-cert5. Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH, MESSAGE. Supported: replaces. Contact: sip:35.197.205.XXX:5060;line=sr-N6IAzJd4WxFLWxVlz.jwWB0yM.y7MlV7zGZlMlvuMx3A. Content-Type: application/sdp. Content-Length: 259. . v=0. o=root 1611167628 1611167628 IN IP4 35.197.206.251. s=Asterisk PBX 1.8.28-cert5. c=IN IP4 35.197.206.251. t=0 0. m=audio 10948 RTP/AVP 8 101. a=rtpmap:8 PCMA/8000. a=rtpmap:101 telephone-event/8000. a=fmtp:101 0-16. a=ptime:20. a=sendrecv. a=rtcp:10949.
U 2018/05/21 10:22:53.206827 88.215.58.YYY:5060 -> 35.197.205.XXX:5060 ACK sip:35.197.205.XXX:5060;line=sr-N6IAzJd4WxFLWxVlz.jwWB0yM.y7MlV7zGZlMlvuMx3A;user=phone SIP/2.0. Max-Forwards: 68. Route: sip:35.197.205.XXX;lr;ftag=3735908572-610467;vsf=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7dXNlcj1waG9uZQ--;vst=AAAAAAAAAAAAAAAAAAAAAAAACQgAAQMbFhsLHTE1OjUwNjA7dXNlcj1waG9uZQ--;did=f17.b7f. To: sip:+441242395XXX@88.215.58.YYY:5060;user=phone;tag=as3147fc45. From: sip:+16098378XXX@88.215.58.YYY;user=phone;tag=3735908572-610467. Call-ID: 5577511-3735908572-610459@MSX163.XXX.com. CSeq: 1 ACK. Allow: PUBLISH,MESSAGE,UPDATE,SUBSCRIBE,REFER,INFO,NOTIFY,OPTIONS,BYE,INVITE,ACK,CANCEL. Via: SIP/2.0/UDP 88.215.58.15:5060;branch=z9hG4bK6c862e8111736dc6d7d22479393d1f2d. Contact: sip:+16098378YYY@88.215.58.YYY:5060. Content-Length: 0.
```
### Possible Solutions
Changed the provider to avoid downtime, but the `empty uri params, skipping` error from `parse_params2` is strange, considering that we do not have a single param but 2.
### Additional Information
* **Kamailio Version** - output of `kamailio -v`
``` version: kamailio 5.0.4 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, 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_LISTEN 16, MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled with gcc 5.4.0 ```
* **Operating System**:
``` Linux gke-lon-1-sbc-in-082a7447-9rll 4.13.0-1011-gcp #15-Ubuntu SMP Mon Feb 12 16:29:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux ```