Re: [SR-Users] uac module From header rewriting problems

Hello, On 7/3/12 8:02 AM, Timo Teras wrote: > Hi, > > I fixed some uac From rewriting issues in commit e1d1c774c9ac0b4d, > however even with the latest versions I'm still seeing corruption > in From headers when they are rewritten for the whole dialogue > (from_restore_mode=auto, the default). > > I spent some time analyzing the problem and the problem seems to > be connected with the fact that only the bitwise difference of the > original and modified URI are stored (XOR). The only purpose for > this appears to be the idea to save only the difference in the rr > params instead of two full URIs. > > However, it appears that in many cases (especially call transfer) > the From header will be altered during dialogue. This is > explicitly allowed in RFC 3261 § 20.20: > The From header field indicates the initiator of the request. > This may be different from the initiator of the dialog. > > I've seen this in practise with few commercial SIP stacks. > Sometimes the changes are minor, or even trivial - but with the > difference encoding having even one character changed (e.g. > case), being deleted or added will result in the whole header > being corrupted. > > I'm now wondering if we should just store both URIs in the rr > params. While taking little more space, it should fix us sending > garbage to the wire (which usually results in dropped call as the > remote will reject the garbage messages). > > Any better ideas? it makes sense storing the entire value. Not sure if anyone else will want to be made configurable via mod param, I will go for simplest approach and have only the correct option, it will help in code maintenance.