Le Tuesday 13 May 2008 20:03:25 Gerrit Renker, vous avez écrit : > Using work-arounds is brittle and frustrating when the API behaviour > suddenly changes. My experience of using such a wrapper was: > > * it passed UDP(-Lite), TCP through without changing the socket type; > * when passed DCCP, it set the socket type to 0, to avoid `ai_socktype > not supported' getaddrinfo error; > * this used to work fine until about January, when something in the > lookup machinery for dual-stack hosts changed: > - before, AF_UNSPEC + ai_socktype=0 put IPv6 first into the result list, > - now the the result order is reversed (IPv4 sockets are returned first) You're probably using a recent libc that applies RFC3484 _properly_. If you still want IPv6 first, no matter what addresses the host has, I think the AI_PASSIVE flag should do the trick. Then again, working around RFC3484 policy is _not_ a good idea. As far as I am concerned, for DCCP, I (meaning VLC) currently use SOCK_STREAM, and overrides the socktype and protocol fields in the socket() call manually - so I don't get a TCP socjet. In any case, getaddrinfo() should be patched to 1/ accept ai_socktype == SOCK_DCCP and ai_protocol == IPPROTO_DCCP, 2/ accept ai_socktype == SOCK_DCCP and ai_protocol == 0, and set ai_protocol to IPPROTO_DCCP in the results, 3/ (perhaps?) accept ai_protocol == IPPROTO_DCCP and ai_socktype == 0, and set ai_socktype to SOCK_DCCP in the results. Similarly: 1/ accept ai_socktype == SOCK_DGRAM and ai_protocol == IPPROTO_UDPLITE, 2/ (intentionally omitted - keep normal UDP non-Lite behavior) 3/ (perhaps?) accept ai_protocol == IPPROTO_UDPLITE and ai_socktype == 0, and set ai_socktype to SOCK_DGRAM in the results. Voilà. Best to check this with Ulrich Drepper, no? -- Rémi Denis-Courmont http://www.remlab.net/ -- To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
