On Wed, 2017-01-11 at 12:34 -0500, Jonathan T. Leighton wrote: > On 1/11/17 11:20 AM, Eric Dumazet wrote: > > On Thu, 2017-01-05 at 16:25 -0500, Jonathan T. Leighton wrote: > >> I've observed TCP using an IPv4-mapped IPv6 address as the source > >> address, which I believe contradicts > >> https://tools.ietf.org/html/rfc6890#page-14 (BCP 153). This occurs when > >> an IPv6 TCP socket, bound to a local IPv4-mapped IPv6 address, attempts > >> to connect to a remote IPv6 address. Presumable connect() should return > >> EAFNOSUPPORT in this case. Please advise me if this is not to > >> appropriate list to report this. > > Hi Jonathan > > > > I believe your concern makes sense. > > Do you have a patch to address this issue ? > > Thanks for responding Eric. I have limited experience with kernel > patches. Nevertheless, unless there's someone with the experience and > time to jump on this, I'm interested in taking a crack at it. I think > the issue certainly warrants attention: instead of returning immediately > with EAFNOSUPPPORT, connect() retransmits its SYN 6 times, ultimately > returning ETIMEDOUT after 127 sec (1+2+4+...+64).
I am not aware of an application trying to perform a bind() to an IPV4 address before a connect() to an IPv6 destination. A kernel fix is certainly something that would detect application bugs in a more friendly way. Thanks !
