[PATCH v3 00/10] Optionally copy all routes and addresses for pasta, allow gateway-less routes

[Stefano Brivio <sbrivio@redhat.com>]

This series, along with pseudo-related fixes, enables:

- optional copy of all routes from selected interface in outer
  namespace, to fix the issue reported by Callum at:
    https://github.com/containers/podman/issues/18539

- optional copy of all addresses, mostly for consistency. It doesn't,
  however, enable assignment of multiple addresses in the sense
  requested at:
    https://bugs.passt.top/show_bug.cgi?id=47

  because the addresses still need to be present on the host, and
  the "outer" address isn't selected depending on the address used
  inside the container

- operation without a gateway address. This is related to:
    https://bugs.passt.top/show_bug.cgi?id=49

  but Wireguard endpoints established outside the container
  can't be used yet as outbound interface (without the workaround
  reported there) for a number of reasons I'm still investigating.
  In any case, the correct route is now configured in the container,
  even without a default gateway on the corresponding host route,
  so we're a bit closer to support that configuration out of the box.

v3:

- in 5/10 and 9/10: mark the new --no-copy-routes and --no-copy-addrs
  options as deprecated to address David's concern. They are hopefully
  not useful and we can drop those, but they're nice to have around at
  the moment in case to debug issues that might be related to this
  series

v2:

- in 3/10, repeat the netlink request once for each RTM_NEWROUTE we're
  going to send as part of the request: routes might depend on each
  other, and this is a somewhat rudimentary, but seemingly robust
  approach to insert all the routes we can insert, without explicitly
  calculating dependencies

- Cc: Andrea, reporter for the issue fixed in 4/10

Stefano Brivio (10):
  netlink: Fix comment about response buffer size for nl_req()
  pasta: Improve error handling on failure to join network namespace
  netlink: Add functionality to copy routes from outer namespace
  conf: --config-net option is for pasta mode only
  conf, pasta: With --config-net, copy all routes by default
  Revert "conf: Adjust netmask on mismatch between IPv4 address/netmask
    and gateway"
  conf: Don't exit if sourced default route has no gateway
  netlink: Add functionality to copy addresses from outer namespace
  conf, pasta: With --config-net, copy all addresses by default
  passt.h: Fix description of pasta_ifi in struct ctx

 conf.c    |  85 +++++++++++++++++++++-------------
 netlink.c | 135 +++++++++++++++++++++++++++++++++++++++++-------------
 netlink.h |  13 ++++--
 passt.1   |  35 +++++++++++++-
 passt.h   |   8 +++-
 pasta.c   |  26 +++++++----
 6 files changed, 221 insertions(+), 81 deletions(-)

-- 
2.39.2