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udp: Update UDP "connection" timestamps in both directions

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A UDP pseudo-connection between port A in the init namespace and port B in
the pasta guest namespace involves two sockets: udp_splice_init[v6][B]
and udp_splice_ns[v6][A].  The socket which originated this "connection"
will be permanent but the other one will be closed on a timeout.

When we get a packet from the originating socket, we update the timeout on
the other socket, but we don't do the same when we get a reply packet from
the other socket.  However any activity on the "connection" probably
indicates that it's still in use.  Without this we could incorrectly time
out a "connection" if it's using a protocol which involves a single
initiating packet, but which then gets continuing replies from the target.

Correct this by updating the timeout on both sockets for a packet in either
direction.  This also updates the timestamps for the permanent originating
sockets which is unnecessary, but harmless.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2022-11-30 15:13:10 +11:00 committed by Stefano Brivio
parent 7610034fef
commit 71d2595a8f
1 changed files with 17 additions and 2 deletions
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19
udp.c
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@ -55,12 +55,15 @@
* - bind in namespace to 127.0.0.1:5000
* - add to epoll with reference: index = 5000, splice = 1, orig = 0,
* ns = 1
* - update udp_splice_ns[V4][5000].ts with current time
* - update udp_splice_init[V4][80].ts and udp_splice_ns[V4][5000].ts with
* current time
*
* - reverse direction: 127.0.0.1:80 -> 127.0.0.1:5000 in namespace socket s,
* having epoll reference: index = 5000, splice = 1, orig = 0, ns = 1
* - if udp_splice_init[V4][80].sock:
* - send to udp_splice_init[V4][80].sock, with destination port 5000
* - update udp_splice_init[V4][80].ts and udp_splice_ns[V4][5000].ts with
* current time
* - otherwise, discard
*
* - from namespace to init:
@ -75,12 +78,15 @@
* - bind in init to 127.0.0.1:2000
* - add to epoll with reference: index = 2000, splice = 1, orig = 0,
* ns = 0
* - update udp_splice_init[V4][2000].ts with current time
* - update udp_splice_ns[V4][22].ts and udp_splice_init[V4][2000].ts with
* current time
*
* - reverse direction: 127.0.0.1:22 -> 127.0.0.1:2000 in init from socket s,
* having epoll reference: index = 2000, splice = 1, orig = 0, ns = 0
* - if udp_splice_ns[V4][22].sock:
* - send to udp_splice_ns[V4][22].sock, with destination port 2000
* - update udp_splice_ns[V4][22].ts and udp_splice_init[V4][2000].ts with
* current time
* - otherwise, discard
*/
@ -539,12 +545,16 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
return;
}
udp_splice_init[v6][dst].ts = now->tv_sec;
udp_splice_ns[v6][src].ts = now->tv_sec;
} else if (!ref.r.p.udp.udp.orig && ref.r.p.udp.udp.ns) {
src += c->udp.fwd_in.rdelta[src];
if (!(s = udp_splice_init[v6][src].sock))
return;
udp_splice_ns[v6][dst].ts = now->tv_sec;
udp_splice_init[v6][src].ts = now->tv_sec;
} else if (ref.r.p.udp.udp.orig && ref.r.p.udp.udp.ns) {
src += c->udp.fwd_in.rdelta[src];
@ -553,12 +563,17 @@ static void udp_sock_handler_splice(const struct ctx *c, union epoll_ref ref,
if (s < 0)
return;
}
udp_splice_ns[v6][dst].ts = now->tv_sec;
udp_splice_init[v6][src].ts = now->tv_sec;
} else if (!ref.r.p.udp.udp.orig && !ref.r.p.udp.udp.ns) {
src += c->udp.fwd_out.rdelta[src];
if (!(s = udp_splice_ns[v6][src].sock))
return;
udp_splice_init[v6][dst].ts = now->tv_sec;
udp_splice_ns[v6][src].ts = now->tv_sec;
} else {
return;
}