Bogus ".local" addresses in candidates

[sobomax]

Describe the bug
Hi, I've seen this once and dismissed as a fluke, however this weird behavior seems to persist, albeit happening not very often. Basically, I am seeing strange "xyz.local" entries in the initial set of candidates provided by the SIP.js in the first INVITE. Usually this happens just once after a fresh connection is established, and after that everything goes to normal. I've observed this with both demo-1 and demo-2 applications.

Logs

27 Jul 06:09:42.276/GLOBAL/b2bua: RECEIVED message from wss:192.168.23.190:61630:
INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/WSS olh5s80k7g78.invalid;branch=z9hG4bK4690236
To: <sip:[email protected]>
From: "Alice" <sip:[email protected]>;tag=8u4ph6ha85
CSeq: 1 INVITE
Call-ID: qq6apt13063fs028r6ab
Max-Forwards: 70
Contact: <sip:[email protected];transport=ws;ob>
Allow: ACK,CANCEL,INVITE,MESSAGE,BYE,OPTIONS,INFO,NOTIFY,REFER
Supported: outbound
User-Agent: SIP.js/0.21.2
Content-Type: application/sdp
Content-Length: 4751

v=0
o=- 2257371366753017904 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0
a=extmap-allow-mixed
a=msid-semantic: WMS 15f7963d-febb-4df3-a12f-9e27a9f037b6
m=video 59387 UDP/TLS/RTP/SAVPF 96 97 102 103 104 105 106 107 108 109 127 125 39 40 45 46 98 99 100 101 112 113 116 117 118
c=IN IP4 207.81.61.34
a=rtcp:9 IN IP4 0.0.0.0
a=candidate:1774936281 1 udp 2113937151 6772ddeb-1940-4ab0-b86b-f6e6bf850c8e.local 59387 typ host generation 0 network-cost 999
a=candidate:23095643 1 udp 1677729535 207.81.61.34 59387 typ srflx raddr 0.0.0.0 rport 0 generation 0 network-cost 999
a=ice-ufrag:9DsD
a=ice-pwd:O5giYsCC21DNfWzZpK1jqlBa
a=ice-options:trickle
a=fingerprint:sha-256 C4:C0:80:C3:3A:57:D5:43:52:5F:9B:93:FF:2A:A6:61:03:4F:A1:FF:52:65:C5:2E:52:2D:C0:A7:74:1E:B4:EF
a=setup:actpass
a=mid:0
a=extmap:1 urn:ietf:params:rtp-hdrext:toffset
a=extmap:2 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=extmap:3 urn:3gpp:video-orientation
a=extmap:4 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
a=extmap:5 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
a=extmap:6 http://www.webrtc.org/experiments/rtp-hdrext/video-content-type
[...]

To Reproduce (if possible)
Steps to reproduce the behavior:

1. Open demo-1/demo-2 application
2. Connect
3. Register
4. Try to place a call

Expected behavior
Only proper candidates should be included into the INVITE

Observed behavior
a=candidate:1774936281 1 udp 2113937151 6772ddeb-1940-4ab0-b86b-f6e6bf850c8e.local 59387 typ host generation 0 network-cost 999

Environment Information

• Sippy B2BUA. master
• Google Chrome. 127.0.6533.72 (Official Build) (64-bit) (cohort: M127 Rollout)

[seanbright]

The candidates are discovered using ICE which is done by the browser, not by sip.js.

I wasn’t able to find any place in the library where “.local” appears as a string.