openConnectionSSL can fail if the system supports ipv6

[bsrkaditya]

openConnectionSSL assumes that the socket's family is AF_INET.

Specifically it is failing for the case of google.

import qualified Data.ByteString.Char8 as BS import Network.Http.Client import OpenSSL (withOpenSSL)

main = withOpenSSL $ do ctx <- baselineContextSSL c <- openConnectionSSL ctx (BS.pack "www.google.com") 443 closeConnection c

[istathar]

Weird. Google is of course one of the test cases I used. Thanks for the patch; I'll have a test here and apply it, I'm sure.

AfC

[istathar]

So I tried 'master' here just now, and it's fine. The system I'm testing on has IPv6 support, and your "test case" above works fine. Can you elaborate further on how to demonstrate the problem?

AfC

[bsrkaditya]

openConnectionSSL uses getAddrInfo to resolve the address of the hostname. getAddrInfo returns a list of addresses, out of which the first one is picked. openConnectionSSL opens a socket of AF_INET family. If the first address happens to be also of AF_INET family, then it is going to work. If however the address happens to be of AF_INET6 family, then it will fail. This is what happened in my case.

So the test is not machine independent. :-) However I can confirm that it is indeed failing in my case. It gives an error: connect: unsupported operation (Address family not supported by protocol) Running it with strace, I got this line: connect(7, {sa_family=AF_INET6, sin6_port=htons(443), inet_pton(AF_INET6, "2404:6800:400a:801::1013", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1 EAFNOSUPPORT (Address family not supported by protocol)

The sort order of getaddrinfo is specified here (section 6, destination address selection): http://www.ietf.org/rfc/rfc3484.txt

By my naive understanding, Rule 7 "Prefer native transport", and Section 5 Rule 5 "Prefer outgoing interface" could be the likely reasons for a difference in the ordering.

[bsrkaditya]

So running:

import Network.Socket import Control.Monad main = getAddrInfo Nothing (Just "www.google.com") (Just "443") >>= mapM_ (putStrLn.show)

I got

AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET6, addrSocketType = Stream, addrProtocol = 6, addrAddress = [2404:6800:400a:801::1010]:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET6, addrSocketType = Datagram, addrProtocol = 17, addrAddress = [2404:6800:400a:801::1010]:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET6, addrSocketType = Raw, addrProtocol = 0, addrAddress = [2404:6800:400a:801::1010]:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Stream, addrProtocol = 6, addrAddress = 74.125.235.242:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Datagram, addrProtocol = 17, addrAddress = 74.125.235.242:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Raw, addrProtocol = 0, addrAddress = 74.125.235.242:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Stream, addrProtocol = 6, addrAddress = 74.125.235.244:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Datagram, addrProtocol = 17, addrAddress = 74.125.235.244:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Raw, addrProtocol = 0, addrAddress = 74.125.235.244:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Stream, addrProtocol = 6, addrAddress = 74.125.235.243:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Datagram, addrProtocol = 17, addrAddress = 74.125.235.243:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Raw, addrProtocol = 0, addrAddress = 74.125.235.243:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Stream, addrProtocol = 6, addrAddress = 74.125.235.240:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Datagram, addrProtocol = 17, addrAddress = 74.125.235.240:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Raw, addrProtocol = 0, addrAddress = 74.125.235.240:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Stream, addrProtocol = 6, addrAddress = 74.125.235.241:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Datagram, addrProtocol = 17, addrAddress = 74.125.235.241:443, addrCanonName = Nothing} AddrInfo {addrFlags = [AI_ADDRCONFIG,AI_V4MAPPED], addrFamily = AF_INET, addrSocketType = Raw, addrProtocol = 0, addrAddress = 74.125.235.241:443, addrCanonName = Nothing}

The address family of the first address is AF_INET6. :-)

[istathar]

@bsrkaditya fair enough; your patch makes sense. I'll double check it doesn't break here (given my otherwise working circumstances) but will apply.

AfC