Hello, Daniel P. Berrangé, le lun. 22 févr. 2021 09:39:41 +0000, a ecrit: > In general callers shouldn't care about which format was parsed. The use > of [] is just a mechanism to reliably separate the port from the address. > Once you have the address part getaddrinfo() will reliably parse the > address into a sockaddr struct on its own.
Agreed. > The is_v6 flag is only needed > for the legacy compat needs in slirp, even that is only if we want to > have strict equivalence with historical behaviour, as opposed to changing > empty string to mean to listen on both IPv4+6 concurrently.. I would say that empty address meaning ipv4+6 looks better to me. Doug Evans, le lun. 22 févr. 2021 09:55:09 -0800, a ecrit: > Hi guys. I think before I submit yet another patchset in this series I need > someone with authority to define the user API for ipv6 host forwarding. > Since the hostfwd syntax is parsed in net/slirp.c, Samuel I think that means > you (based on what I'm reading in MAINTAINERS). Well, I'm not maintainer of the user API actually. That'd rather be Markus Armbruster, now Cc-ed, who devises the command-line options, QAPI, etc. > Based on what Maxim originally wrote I was going with addresses wrapped in [] > mean ipv6, but Daniel does not want that. Specifying [127.0.0.1] would be odd, but for instance ssh localhost -D '[127.0.0.1]':23456 happens to listen on 127.0.0.1. So I would say that common practice really is that [] only matters for syntax, and not semantic. > There are issues to consider of course. > Note that one issue I am leaving for later (i.e., I don't want to drag this > patch series out to include it), is whether and how to support ipv4-host-> > ipv6-guest forwarding and vice versa. Can libslirp support this? That would be feasible yes: since the data flow is completely rebuilt between the host and the guest, there is no remnant of the IP version. It was simpler to have e.g. udp_listen and udp6_listen separate to keep uint32_t / in6_addr parameters, but there is no strict reason for this: the haddr is only passed to the bind() call, and the laddr is only recorded in the so. Put another way, a refactoring patch could be to just hand udp_listen two sockaddrs, and it will just work fine. We'd then introduce a slirp_add_hostfwd that takes two sockaddr instead of host/port. > Setting cross-forwarding aside, we can't break existing uses of course, so > that > means that one issue is that if [] is not used to identify ipv6 addresses then > something like ",ipv6" will be needed as a separate argument; otherwise the > empty address "" will be ambiguous. (as I mentioned above, I'd say empty address "" should mean ipv4+ipv6) > + Examples: > + hostfwd_add net0 tcp:127.0.0.1:10022-:22 > + hostfwd_add net0 tcp:[::1]:10022-[fe80::1:2:3:4]:22 Yep, that looks good to me. Samuel
