net: Dial, Listen and ResolveAddr fail when the ipv6 entry in /etc/hosts has a zone identifier

[mikioh]

According to issue #8235, all connection setup and resolveaddr functions fail when the
target is has an ipv6 scoped addressing zone identifier. For example,

/etc/hosts
localhost fe80::1%lo0
livingroom fe80::2%en1
garage fe80::2%en2

Listen("tcp6", "localhost:0)"
Dial("tcp6", "livingloom:1234")
ResolveTCPAddr("tcp", "garage:http")

[ianlancetaylor]

Comment 1:

Labels changed: added repo-main, release-go1.4.

[mikioh]

Comment 2:

To fix this issue, we need to handle zone identifier appropriately at;
- cgoLookupIPCNAME in cgo_unix.go, fortunately getaddrinfo returns ipv6 address with
zone identifier,
- readHosts in hosts.go, it doesn't parse ipv6 address with zone identifier correctly,
- resolveInternetAddr in ipsock.go and lookupIP in lookup.go, for now both functions
drop ipv6 zone identifier.

[rsc]

Comment 3:

Too late for 1.4.

Labels changed: added release-go1.5, removed release-go1.4.

Status changed to Accepted.

[mikioh]

Comment 4:

Labels changed: added release-none, removed release-go1.5.

[gopherbot]

CL https://golang.org/cl/10306 mentions this issue.