In tcp_sock_handler() we split off to handle spliced sockets before
checking anything else. However the first steps of the "new connection"
path for each case are the same: allocate a connection entry and accept()
the connection.
Remove this duplication by making tcp_conn_from_sock() handle both spliced
and non-spliced cases, with help from more specific tcp_tap_conn_from_sock
and tcp_splice_conn_from_sock functions for the later stages which differ.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
These two functions scan all the non-splced and spliced connections
respectively and perform timed updates on them. Avoid scanning the now
unified table twice, by having tcp_timer scan it once calling the
relevant per-connection function for each one.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
These two functions each step through non-spliced and spliced connections
respectively and clean up entries for closed connections. To avoid
scanning the connection table twice, we merge these into a single function
which scans the unified table and performs the appropriate sort of cleanup
action on each one.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Currently spliced and non-spliced connections are stored in completely
separate tables, so there are completely independent limits on the number
of spliced and non-spliced connections. This is a bit counter-intuitive.
More importantly, the fact that the tables are separate prevents us from
unifying some other logic between the two cases. So, merge these two
tables into one, using the 'c.spliced' common field to distinguish between
them when necessary.
For now we keep a common limit of 128k connections, whether they're spliced
or non-spliced, which means we save memory overall. If necessary we could
increase this to a 256k or higher total, which would cost memory but give
some more flexibility.
For now, the code paths which need to step through all extant connections
are still separate for the two cases, just skipping over entries which
aren't for them. We'll improve that in later patches.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This obvious include was omitted, which means that declarations in the
header weren't checked against definitions in the .c file. This shows up
an old declaration for a function that is now static, and a duplicate
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Implement a packet abstraction providing boundary and size checks
based on packet descriptors: packets stored in a buffer can be queued
into a pool (without storage of its own), and data can be retrieved
referring to an index in the pool, specifying offset and length.
Checks ensure data is not read outside the boundaries of buffer and
descriptors, and that packets added to a pool are within the buffer
range with valid offset and indices.
This implies a wider rework: usage of the "queueing" part of the
abstraction mostly affects tap_handler_{passt,pasta}() functions and
their callees, while the "fetching" part affects all the guest or tap
facing implementations: TCP, UDP, ICMP, ARP, NDP, DHCP and DHCPv6
handlers.
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We can't take for granted that the hard limit for open files is
big enough as to allow to delay closing sockets to a timer.
Store the value of RTLIMIT_NOFILE we set at start, and use it to
understand if we're approaching the limit with pending, spliced
TCP connections. If that's the case, close sockets right away as
soon as they're not needed, instead of deferring this task to a
timer.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Using events and flags instead of states makes the implementation
much more straightforward: actions are mostly centered on events
that occurred on the connection rather than states.
An example is given by the ESTABLISHED_SOCK_FIN_SENT and
FIN_WAIT_1_SOCK_FIN abominations: we don't actually care about
which side started closing the connection to handle closing of
connection halves.
Split out the spliced implementation, as it has very little in
common with the "regular" TCP path.
Refactor things here and there to improve clarity. Add helpers
to trace where resets and flag settings come from.
No functional changes intended.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
