linux-toradex.git/net/ipv4/syncookies.c, branch v4.1

tcp: fix ipv4 mapped request socks

2015-03-25T04:57:48+00:00

ss should display ipv4 mapped request sockets like this :

tcp    SYN-RECV   0      0  ::ffff:192.168.0.1:8080   ::ffff:192.0.2.1:35261

and not like this :

tcp    SYN-RECV   0      0  192.168.0.1:8080   192.0.2.1:35261

We should init ireq->ireq_family based on listener sk_family,
not the actual protocol carried by SYN packet.

This means we can set ireq_family in inet_reqsk_alloc()

Fixes: 3f66b083a5b7 ("inet: introduce ireq_family")
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: get rid of central tcp/dccp listener timer

2015-03-20T16:40:25+00:00

One of the major issue for TCP is the SYNACK rtx handling,
done by inet_csk_reqsk_queue_prune(), fired by the keepalive
timer of a TCP_LISTEN socket.

This function runs for awful long times, with socket lock held,
meaning that other cpus needing this lock have to spin for hundred of ms.

SYNACK are sent in huge bursts, likely to cause severe drops anyway.

This model was OK 15 years ago when memory was very tight.

We now can afford to have a timer per request sock.

Timer invocations no longer need to lock the listener,
and can be run from all cpus in parallel.

With following patch increasing somaxconn width to 32 bits,
I tested a listener with more than 4 million active request sockets,
and a steady SYNFLOOD of ~200,000 SYN per second.
Host was sending ~830,000 SYNACK per second.

This is ~100 times more what we could achieve before this patch.

Later, we will get rid of the listener hash and use ehash instead.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: request sock should init IPv6/IPv4 addresses

2015-03-19T02:00:35+00:00

In order to be able to use sk_ehashfn() for request socks,
we need to initialize their IPv6/IPv4 addresses.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: fix request sock refcounting

2015-03-18T02:02:29+00:00

While testing last patch series, I found req sock refcounting was wrong.

We must set skc_refcnt to 1 for all request socks added in hashes,
but also on request sockets created by FastOpen or syncookies.

It is tricky because we need to defer this initialization so that
future RCU lookups do not try to take a refcount on a not yet
fully initialized request socket.

Also get rid of ireq_refcnt alias.

Signed-off-by: Eric Dumazet 
Fixes: 13854e5a6046 ("inet: add proper refcounting to request sock")
Signed-off-by: David S. Miller

tcp: rename struct tcp_request_sock listener

2015-03-18T02:01:56+00:00

The listener field in struct tcp_request_sock is a pointer
back to the listener. We now have req->rsk_listener, so TCP
only needs one boolean and not a full pointer.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: add sk_listener argument to inet_reqsk_alloc()

2015-03-18T02:01:55+00:00

listener socket can be used to set net pointer, and will
be later used to hold a reference on listener.

Add a const qualifier to first argument (struct request_sock_ops *),
and factorize all write_pnet(&ireq->ireq_net, sock_net(sk));

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: add proper refcounting to request sock

2015-03-16T19:55:29+00:00

reqsk_put() is the generic function that should be used
to release a refcount (and automatically call reqsk_free())

reqsk_free() might be called if refcount is known to be 0
or undefined.

refcnt is set to one in inet_csk_reqsk_queue_add()

As request socks are not yet in global ehash table,
I added temporary debugging checks in reqsk_put() and reqsk_free()

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: fill request sock ir_iif for IPv4

2015-03-14T19:05:10+00:00

Once request socks will be in ehash table, they will need to have
a valid ir_iff field.

This is currently true only for IPv6. This patch extends support
for IPv4 as well.

This means inet_diag_fill_req() can now properly use ir_iif,
which is better for IPv6 link locals anyway, as request sockets
and established sockets will propagate consistent netlink idiag_if.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

inet: introduce ireq_family

2015-03-13T02:58:13+00:00

Before inserting request socks into general hash table,
fill their socket family.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: fix CONFIG_NET_NS=n compilation

2015-03-12T03:28:49+00:00

I forgot to use write_pnet() in three locations.

Signed-off-by: Eric Dumazet 
Fixes: 33cf7c90fe2f9 ("net: add real socket cookies")
Reported-by: kbuild test robot 
Signed-off-by: David S. Miller