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

[David Gibson <david@gibson.dropbear.id.au>]

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.

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

-- 
2.46.0