Re: [PATCH 00/22] RFC: Allow configuration of special case NATs

[Paul Holzinger <pholzing@redhat.com>]

Hi,

On 16/08/2024 07:39, David Gibson wrote:
> Based on Stefano's recent patch for faster tests.
>
> Allow the user to specify which addresses are translated when used by
> the guest, rather than always being the gateway address or nothing.
> We also allow this remapping to go to the host's global address (more
> precisely the address assigned to the guest) rather than just host
> loopback.
>
> Suggestions for better names for the new options in patches 20 & 22
> are most welcome.
>
> Along the way to implementing that make many changes to clarify what
> various addresses we track mean, fixing a number of small bugs as
> well.
>
> NOTE: there is a bug in 21/22 which breaks some of the passt_tcp perf
> tests.  I haven't managed to figure out why it's causing the problem,
> or even what the exact triggering conditions are (running the single
> stalling iperf alone doesn't do it).  Have to wrap up for today, so I
> thought I'd get this out for review anyway.
>
> Paul, amongst other things, I think this will allow podman to
> (finally) nicely address #19213, picking an address to remap to the
> host's external address with --nat-guest-addr, much like it already
> uses --dns-forward.

Thanks this looks promising. I will try to test it out next week.

No strong feelings about the naming but how about s/--nat/--map/ for the 
options?

>
> David Gibson (22):
>    treewide: Use "our address" instead of "forwarding address"
>    util: Helper for formatting MAC addresses
>    treewide: Rename MAC address fields for clarity
>    treewide: Use struct assignment instead of memcpy() for IP addresses
>    conf: Use array indices rather than pointers for DNS array slots
>    conf: More accurately count entries added in get_dns()
>    conf: Move DNS array bounds checks into add_dns[46]
>    conf: Move adding of a nameserver from resolv.conf into subfunction
>    conf: Correct setting of dns_match address in add_dns6()
>    conf: Treat --dns addresses as guest visible addresses
>    conf: Remove incorrect initialisation of addr_ll_seen
>    util: Correct sock_l4() binding for link local addresses
>    treewide: Change misleading 'addr_ll' name
>    Clarify which addresses in ip[46]_ctx are meaningful where
>    Initialise our_tap_ll to ip6.gw when suitable
>    fwd: Helpers to clarify what host addresses aren't guest accessible
>    fwd: Split notion of "our tap address" from gateway for IPv4
>    Don't take "our" MAC address from the host
>    conf, fwd: Split notion of gateway/router from guest-visible host
>      address
>    conf: Allow address remapped to host to be configured
>    fwd: Distinguish translatable from untranslatable addresses on inbound
>    fwd, conf: Allow NAT of the guest's assigned address
>
>   arp.c                 |   4 +-
>   conf.c                | 328 +++++++++++++++++++++++++-----------------
>   dhcp.c                |  19 +--
>   dhcpv6.c              |  21 +--
>   flow.c                |  72 +++++-----
>   flow.h                |  18 +--
>   fwd.c                 | 170 +++++++++++++++++-----
>   icmp.c                |   4 +-
>   ndp.c                 |   9 +-
>   passt.1               |  45 +++++-
>   passt.c               |   2 +-
>   passt.h               |  53 +++++--
>   pasta.c               |  14 +-
>   tap.c                 |  12 +-
>   tcp.c                 |  33 ++---
>   tcp_internal.h        |   2 +-
>   test/lib/setup        |  11 +-
>   test/passt_in_ns/dhcp |  73 ++++++++++
>   test/passt_in_ns/tcp  |  38 +++--
>   test/passt_in_ns/udp  |  22 +--
>   test/perf/passt_tcp   |  33 ++---
>   test/perf/passt_udp   |  31 ++--
>   test/perf/pasta_tcp   |  29 ++--
>   test/perf/pasta_udp   |  25 ++--
>   test/run              |   4 +-
>   udp.c                 |  12 +-
>   util.c                |  22 ++-
>   util.h                |   4 +-
>   28 files changed, 719 insertions(+), 391 deletions(-)
>   create mode 100644 test/passt_in_ns/dhcp
>
-- 
Paul Holzinger