Changes from v4:
- Rename ConnectHandler to NonBlockingConnectHandler
- move function comments to functions definitions
- move connect_state allocation to outside of the loop
- fix comments text
Changes from v3:
- add missing parenthesis QEMU_SOCKET_RC_INPROGRESS macro
- remove "block" from dummy_opts
- remove in_progress from external API (inet_connect_opts and
inet_nonblocking_connect)
- Allocate ConnectState inside inet_connect_opts, this make the
structure internal to qemu-sockets.c
- fix migrate_fd_cleanup to handle invalid fd.
Changes from v2:
- remove the use of getnameinfo
- remove errp for inet_connect_addr
- remove QemuOpt "block"
- fix errors in wait_for_connect
- pass ConnectState as a parameter to allow concurrent connect ops
getaddrinfo can give us a list of addresses, but we only try to
connect to the first one. If that fails we never proceed to
the next one. This is common on desktop setups that often have ipv6
configured but not actually working.
A simple way to reproduce the problem is migration:
for the destination use -incoming tcp:0:4444, run migrate -d tcp:localhost:4444
migration will fail on hosts that have both IPv4 and IPV6 address for localhost.
To fix this, refactor address resolution code and make inet_nonblocking_connect
retry connection with a different address.