passt/icmp.h, branch c9s

icmp: Use 'flowside' epoll references for ping sockets

2024-03-12T00:49:05+00:00

Currently ping sockets use a custom epoll reference type which includes
the ICMP id.  However, now that we have entries in the flow table for
ping flows, finding that is sufficient to get everything else we want,
including the id.  Therefore remove the icmp_epoll_ref type and use the
general 'flowside' field for ping sockets.

Having done this we no longer need separate EPOLL_TYPE_ICMP and
EPOLL_TYPE_ICMPV6 reference types, because we can easily determine
which case we have from the flow type. Merge both types into
EPOLL_TYPE_PING.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

icmp: Store ping socket information in flow table

2024-03-12T00:34:45+00:00

Currently icmp_id_map[][] stores information about ping sockets in a
bespoke structure.  Move the same information into new types of flow
in the flow table.  To match that change, replace the existing ICMP
timer with a flow-based timer for expiring ping sockets.  This has the
advantage that we only need to scan the active flows, not all possible
ids.

We convert icmp_id_map[][] to point to the flow table entries, rather
than containing its own information.  We do still use that array for
locating the right ping flows, rather than using a "flow native" form
of lookup for the time being.

Signed-off-by: David Gibson 
[sbrivio: Update id_sock description in comment to icmp_ping_new()]
Signed-off-by: Stefano Brivio

treewide: Use sa_family_t for address family variables

2024-02-27T11:52:02+00:00

Sometimes we use sa_family_t for variables and parameters containing a
socket address family, other times we use a plain int.  Since sa_family_t
is what's actually used in struct sockaddr and friends, standardise on
that.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

icmp: Consolidate icmp_sock_handler() with icmpv6_sock_handler()

2024-01-22T22:36:51+00:00

Currently we have separate handlers for ICMP and ICMPv6 ping replies.
Although there are a number of points of difference, with some creative
refactoring we can combine these together sensibly.  Although it doesn't
save a vast amount of code, it does make it clearer that we're performing
basically the same steps for each case.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

icmp: Simplify socket expiry scanning

2024-01-22T22:36:46+00:00

Currently we use icmp_act[] to scan for ICMP ids which might have an open
socket which could time out.  However icmp_act[] contains no information
that's not already in icmp_id_map[] - it's just an "index" which allows
scanning for relevant entries with less cache footprint.

We only scan for ICMP socket expiry every 1s, though, so it's not clear
that cache footprint really matters.  Furthermore, there's no strong reason
we need to scan even that often - the timeout is fairly arbitrary and
approximate.

So, eliminate icmp_act[] in favour of directly scanning icmp_id_map[] and
compensate for the cache impact by reducing the scan frequency to once
every 10s.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

treewide: Standardise on 'now' for current timestamp variables

2024-01-22T22:35:10+00:00

In a number of places we pass around a struct timespec representing the
(more or less) current time.  Sometimes we call it 'now', and sometimes we
call it 'ts'.  Standardise on the more informative 'now'.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

pif: Pass originating pif to tap handler functions

2023-11-07T08:53:45+00:00

For now, packets passed to the various *_tap_handler() functions always
come from the single "tap" interface.  We want to allow the possibility to
broaden that in future.  As preparation for that, have the code in tap.c
pass the pif id of the originating interface to each of those handler
functions.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

tap: Pass source address to protocol handler functions

2023-08-22T10:15:21+00:00

The tap code passes the IPv4 or IPv6 destination address of packets it
receives to the protocol specific code.  Currently that protocol code
doesn't use the source address, but we want it to in future.  So, in
preparation, pass the IPv4/IPv6 source address of tap packets to those
functions as well.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

epoll: Split handling of ICMP and ICMPv6 sockets

2023-08-13T15:30:07+00:00

We have different epoll type values for ICMP and ICMPv6 sockets, but they
both call the same handler function, icmp_sock_handler().  However that
function does essentially nothing in common for the two cases.  So, split
it into icmp_sock_handler() and icmpv6_sock_handler() and dispatch them
separately from the top level.

While we're there remove some parameters that the function was never using
anyway.  Also move the test for c->no_icmp into the functions, so that all
the logic specific to ICMP is within the handler, rather than in the top
level dispatch code.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

Use C11 anonymous members to make poll refs less verbose to use

2023-08-03T23:17:57+00:00

union epoll_ref has a deeply nested set of structs and unions to let us
subdivide it into the various different fields we want.  This means that
referencing elements can involve an awkward long string of intermediate
fields.

Using C11 anonymous structs and unions lets us do this less clumsily.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio