tcp: Fixes for closing states, spliced connections, out-of-order packets, etc.

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This fixes a number of issues found with some heavier testing with
uperf and neper:

- in most closing states, we can still accept data, check for EPOLLIN
  when appropriate

- introduce a new state, ESTABLISHED_SOCK_FIN_SENT, to track the fact
  we already sent a FIN segment to the tap device, for proper sequence
  number bookkeeping

- for pasta mode only: spliced connections also need tracking of
  (inferred) FIN segments and clean half-pipe shutdowns

- streamline resetting epoll_wait bitmaps with a new function,
  tcp_tap_epoll_mask(), instead of repeating the logic all over the
  place

- set EPOLLET for tap connections too, whenever we are waiting for
  EPOLLRDHUP or an event from the tap to proceed with data transfer,
  to avoid useless loops with EPOLLIN set

- impose an additional limit on the sending window advertised to the
  guest, given by SO_SNDBUF: it makes no sense to completely fill
  the sending buffer and send a zero window: stop a bit before we
  hit that

- handle *all* interrupted system calls as needed

- simplify the logic for reordering of out-of-order segments received
  from tap: it's not a corner case, and the previous logic allowed
  for deadloops

- fix comparison of seen IPv4 address when we get a new connection
  from a socket directed to the configured guest address

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

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This commit is contained in:

Stefano Brivio 2021-09-09 15:16:46 +02:00

parent 5e23b1ef44

commit e58828f340

1 changed files with 402 additions and 209 deletions

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