connect: treat an interface bindlocal() problem as a non-fatal error
I am using curl_easy_setopt(CURLOPT_INTERFACE, "if!something") to force
transfers to use a particular interface but the transfer fails with
CURLE_INTERFACE_FAILED, "Failed binding local connection end" if the
interface I specify has no IPv6 address. The cause is as follows:
The remote hostname resolves successfully and has an IPv6 address and an
IPv4 address.
cURL attempts to connect to the IPv6 address first.
bindlocal (in lib/connect.c) fails because Curl_if2ip cannot find an
IPv6 address on the interface.
This is a fatal error in singleipconnect()
This change will make cURL try the next IP address in the list.
Also included are two changes related to IPv6 address scope:
- Filter the choice of address in Curl_if2ip to only consider addresses
with the same scope ID as the connection address (mismatched scope for
local and remote address does not result in a working connection).
- bindlocal was ignoring the scope ID of addresses returned by
Curl_if2ip . Now it uses them.
projects / curl / commit