Since commit 4f008781 ("sctp: apply rhashtable api to send/recv
path"), sctp uses transport rhashtable with .obj_cmpfn sctp_hash_cmp,
in which it compares the members of the transport with the rhashtable
args to check if it's the right transport.

But sctp uses the transport without holding it in sctp_hash_cmp, it can
cause a use-after-free panic. As after it gets transport from hashtable,
another CPU may close the sk and free the asoc. In sctp_association_free,
it frees all the transports, meanwhile, the assoc's refcnt may be reduced
to 0, assoc can be destroyed by sctp_association_destroy.

So after that, transport->assoc is actually an unavailable memory address
in sctp_hash_cmp. Although sctp_hash_cmp is under rcu_read_lock, it still
can not avoid this, as assoc is not freed by RCU.

This patch is to hold the transport before checking it's members with
sctp_transport_hold, in which it checks the refcnt first, holds it if
it's not 0.

Fixes: 4f008781 ("sctp: apply rhashtable api to send/recv path")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Previously, without GSO, it was easy to identify it: if the chunk didn't
fit and there was no data chunk in the packet yet, we could fragment at
IP level. So if there was an auth chunk and we were bundling a big data
chunk, it would fragment regardless of the size of the auth chunk. This
also works for the context of PMTU reductions.

But with GSO, we cannot distinguish such PMTU events anymore, as the
packet is allowed to exceed PMTU.

So we need another check: to ensure that the chunk that we are adding,
actually fits the current PMTU. If it doesn't, trigger a flush and let
it be fragmented at IP level in the next round.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function sctp_diag_dump_one() currently performs a memcpy()
of 64 bytes from a 16 byte field into another 16 byte field. Fix
by using correct size, use sizeof to obtain correct size instead
of using a hard-coded constant.

Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Signed-off-by: NLance Richardson <lrichard@redhat.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because otherwise when crc computation is still needed it's way more
expensive than on a linear buffer to the point that it affects
performance.

It's so expensive that netperf test gives a perf output as below:

Overhead  Command         Shared Object       Symbol
  18,62%  netserver       [kernel.vmlinux]    [k] crc32_generic_shift
   2,57%  netserver       [kernel.vmlinux]    [k] __pskb_pull_tail
   1,94%  netserver       [kernel.vmlinux]    [k] fib_table_lookup
   1,90%  netserver       [kernel.vmlinux]    [k] copy_user_enhanced_fast_string
   1,66%  swapper         [kernel.vmlinux]    [k] intel_idle
   1,63%  netserver       [kernel.vmlinux]    [k] _raw_spin_lock
   1,59%  netserver       [sctp]              [k] sctp_packet_transmit
   1,55%  netserver       [kernel.vmlinux]    [k] memcpy_erms
   1,42%  netserver       [sctp]              [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

212992 212992  12000    10.00      3016.42   2.88     3.78     1.874   2.462

After patch:
Overhead  Command         Shared Object      Symbol
   2,75%  netserver       [kernel.vmlinux]   [k] memcpy_erms
   2,63%  netserver       [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
   2,39%  netserver       [kernel.vmlinux]   [k] fib_table_lookup
   2,04%  netserver       [kernel.vmlinux]   [k] __pskb_pull_tail
   1,91%  netserver       [kernel.vmlinux]   [k] _raw_spin_lock
   1,91%  netserver       [sctp]             [k] sctp_packet_transmit
   1,72%  netserver       [mlx4_en]          [k] mlx4_en_process_rx_cq
   1,68%  netserver       [sctp]             [k] sctp_rcv

# netperf -H 192.168.10.1 -l 10 -t SCTP_STREAM -cC -- -m 12000
SCTP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.10.1 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

212992 212992  12000    10.00      3681.77   3.83     3.46     2.045   1.849

Fixes: 3acb50c1 ("sctp: delay as much as possible skb_linearize")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_transport_seq_start() does not currently clear iter->start_fail on
success, but relies on it being zero when it is allocated (by
seq_open_net()).

This can be a problem in the following sequence:

    open() // allocates iter (and implicitly sets iter->start_fail = 0)
    read()
     - iter->start() // fails and sets iter->start_fail = 1
     - iter->stop() // doesn't call sctp_transport_walk_stop() (correct)
    read() again
     - iter->start() // succeeds, but doesn't change iter->start_fail
     - iter->stop() // doesn't call sctp_transport_walk_stop() (wrong)

We should initialize sctp_ht_iter::start_fail to zero if ->start()
succeeds, otherwise it's possible that we leave an old value of 1 there,
which will cause ->stop() to not call sctp_transport_walk_stop(), which
causes all sorts of problems like not calling rcu_read_unlock() (and
preempt_enable()), eventually leading to more warnings like this:

    BUG: sleeping function called from invalid context at mm/slab.h:388
    in_atomic(): 0, irqs_disabled(): 0, pid: 16551, name: trinity-c2
    Preemption disabled at:[<ffffffff819bceb6>] rhashtable_walk_start+0x46/0x150

     [<ffffffff81149abb>] preempt_count_add+0x1fb/0x280
     [<ffffffff83295892>] _raw_spin_lock+0x12/0x40
     [<ffffffff819bceb6>] rhashtable_walk_start+0x46/0x150
     [<ffffffff82ec665f>] sctp_transport_walk_start+0x2f/0x60
     [<ffffffff82edda1d>] sctp_transport_seq_start+0x4d/0x150
     [<ffffffff81439e50>] traverse+0x170/0x850
     [<ffffffff8143aeec>] seq_read+0x7cc/0x1180
     [<ffffffff814f996c>] proc_reg_read+0xbc/0x180
     [<ffffffff813d0384>] do_loop_readv_writev+0x134/0x210
     [<ffffffff813d2a95>] do_readv_writev+0x565/0x660
     [<ffffffff813d6857>] vfs_readv+0x67/0xa0
     [<ffffffff813d6c16>] do_preadv+0x126/0x170
     [<ffffffff813d710c>] SyS_preadv+0xc/0x10
     [<ffffffff8100334c>] do_syscall_64+0x19c/0x410
     [<ffffffff83296225>] return_from_SYSCALL_64+0x0/0x6a
     [<ffffffffffffffff>] 0xffffffffffffffff

Notice that this is a subtly different stacktrace from the one in commit
5fc382d8 ("net/sctp: terminate rhashtable walk correctly").

Cc: Xin Long <lucien.xin@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Acked-By: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 52253db9 ("sctp: also point GSO head_skb to the sk when
it's available") used event->chunk->head_skb to get the head_skb in
sctp_ulpevent_set_owner().

But at that moment, the event->chunk was NULL, as it cloned the skb
in sctp_ulpevent_make_rcvmsg(). Therefore, that patch didn't really
work.

This patch is to move the event->chunk initialization before calling
sctp_ulpevent_receive_data() so that it uses event->chunk when it's
valid.

Fixes: 52253db9 ("sctp: also point GSO head_skb to the sk when it's available")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since 'ss' always adds TCPF_CLOSE to idiag_states flags, sctp_diag can't
rely upon TCPF_LISTEN flag solely being present when listening sockets
are requested.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The asoc's timer value is not kept in asoc->timeouts array but in it's
primary transport instead.

Furthermore, we must export the timer only if it is pending, otherwise
the value will underrun when stored in an unsigned variable and
user space will only see a very large timeout value.
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 141ddefc ("sctp: change sk state to CLOSED instead of
CLOSING in sctp_sock_migrate") changed sk state to CLOSED if the
assoc is closed when sctp_accept clones a new sk.

If there is still data in sk receive queue, users will not be able
to read it any more, as sctp_recvmsg returns directly if sk state
is CLOSED.

This patch is to add CLOSED state check in sctp_recvmsg to allow
reading data from TCP-style sk with CLOSED state as what TCP does.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Prior to this patch, once sctp received SHUTDOWN or shutdown with RD,
sk->sk_shutdown would be set with RCV_SHUTDOWN, and all events would
be dropped in sctp_ulpq_tail_event(). It would cause:

1. some notifications couldn't be received by users. like
   SCTP_SHUTDOWN_COMP generated by sctp_sf_do_4_C().

2. sctp would also never trigger sk_data_ready when the association
   was closed, making it harder to identify the end of the association
   by calling recvmsg() and getting an EOF. It was not convenient for
   kernel users.

The check here should be stopping delivering DATA chunks after receiving
SHUTDOWN, and stopping delivering ANY chunks after sctp_close().

So this patch is to allow notifications to enqueue into receive queue
even if sk->sk_shutdown is set to RCV_SHUTDOWN in sctp_ulpq_tail_event,
but if sk->sk_shutdown == RCV_SHUTDOWN | SEND_SHUTDOWN, it drops all
events.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp needs to queue auth chunk back when we know that we are going
to generate another segment. But commit f1533cce ("sctp: fix
panic when sending auth chunks") requeues the last chunk processed
which is probably not the auth chunk.

It causes panic when calculating the MAC in sctp_auth_calculate_hmac(),
as the incorrect offset of the auth chunk in skb->data.

This fix is to requeue it by using packet->auth.

Fixes: f1533cce ("sctp: fix panic when sending auth chunks")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I was seeing a lot of these:

    BUG: sleeping function called from invalid context at mm/slab.h:388
    in_atomic(): 0, irqs_disabled(): 0, pid: 14971, name: trinity-c2
    Preemption disabled at:[<ffffffff819bcd46>] rhashtable_walk_start+0x46/0x150

     [<ffffffff81149abb>] preempt_count_add+0x1fb/0x280
     [<ffffffff83295722>] _raw_spin_lock+0x12/0x40
     [<ffffffff811aac87>] console_unlock+0x2f7/0x930
     [<ffffffff811ab5bb>] vprintk_emit+0x2fb/0x520
     [<ffffffff811aba6a>] vprintk_default+0x1a/0x20
     [<ffffffff812c171a>] printk+0x94/0xb0
     [<ffffffff811d6ed0>] print_stack_trace+0xe0/0x170
     [<ffffffff8115835e>] ___might_sleep+0x3be/0x460
     [<ffffffff81158490>] __might_sleep+0x90/0x1a0
     [<ffffffff8139b823>] kmem_cache_alloc+0x153/0x1e0
     [<ffffffff819bca1e>] rhashtable_walk_init+0xfe/0x2d0
     [<ffffffff82ec64de>] sctp_transport_walk_start+0x1e/0x60
     [<ffffffff82edd8ad>] sctp_transport_seq_start+0x4d/0x150
     [<ffffffff8143a82b>] seq_read+0x27b/0x1180
     [<ffffffff814f97fc>] proc_reg_read+0xbc/0x180
     [<ffffffff813d471b>] __vfs_read+0xdb/0x610
     [<ffffffff813d4d3a>] vfs_read+0xea/0x2d0
     [<ffffffff813d615b>] SyS_pread64+0x11b/0x150
     [<ffffffff8100334c>] do_syscall_64+0x19c/0x410
     [<ffffffff832960a5>] return_from_SYSCALL_64+0x0/0x6a
     [<ffffffffffffffff>] 0xffffffffffffffff

Apparently we always need to call rhashtable_walk_stop(), even when
rhashtable_walk_start() fails:

 * rhashtable_walk_start - Start a hash table walk
 * @iter:       Hash table iterator
 *
 * Start a hash table walk.  Note that we take the RCU lock in all
 * cases including when we return an error.  So you must always call
 * rhashtable_walk_stop to clean up.

otherwise we never call rcu_read_unlock() and we get the splat above.

Fixes: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
See-also: 53fa1036 ("sctp: fix some rhashtable functions using in sctp proc/diag")
See-also: f2dba9c6 ("rhashtable: Introduce rhashtable_walk_*")
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: stable@vger.kernel.org
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The head skb for GSO packets won't travel through the inner depths of
SCTP stack as it doesn't contain any chunks on it. That means skb->sk
doesn't get set and then when sctp_recvmsg() calls
sctp_inet6_skb_msgname() on the head_skb it panics, as this last needs
to check flags at the socket (sp->v4mapped).

The fix is to initialize skb->sk for th head skb once we are able to do
it. That is, when the first chunk is processed.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that the backlog processing is called with BH enabled, we have to
disable BH before taking the socket lock via bh_lock_sock() otherwise
it may dead lock:

sctp_backlog_rcv()
                bh_lock_sock(sk);

                if (sock_owned_by_user(sk)) {
                        if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
                                sctp_chunk_free(chunk);
                        else
                                backloged = 1;
                } else
                        sctp_inq_push(inqueue, chunk);

                bh_unlock_sock(sk);

while sctp_inq_push() was disabling/enabling BH, but enabling BH
triggers pending softirq, which then may try to re-lock the socket in
sctp_rcv().

[  219.187215]  <IRQ>
[  219.187217]  [<ffffffff817ca3e0>] _raw_spin_lock+0x20/0x30
[  219.187223]  [<ffffffffa041888c>] sctp_rcv+0x48c/0xba0 [sctp]
[  219.187225]  [<ffffffff816e7db2>] ? nf_iterate+0x62/0x80
[  219.187226]  [<ffffffff816f1b14>] ip_local_deliver_finish+0x94/0x1e0
[  219.187228]  [<ffffffff816f1e1f>] ip_local_deliver+0x6f/0xf0
[  219.187229]  [<ffffffff816f1a80>] ? ip_rcv_finish+0x3b0/0x3b0
[  219.187230]  [<ffffffff816f17a8>] ip_rcv_finish+0xd8/0x3b0
[  219.187232]  [<ffffffff816f2122>] ip_rcv+0x282/0x3a0
[  219.187233]  [<ffffffff810d8bb6>] ? update_curr+0x66/0x180
[  219.187235]  [<ffffffff816abac4>] __netif_receive_skb_core+0x524/0xa90
[  219.187236]  [<ffffffff810d8e00>] ? update_cfs_shares+0x30/0xf0
[  219.187237]  [<ffffffff810d557c>] ? __enqueue_entity+0x6c/0x70
[  219.187239]  [<ffffffff810dc454>] ? enqueue_entity+0x204/0xdf0
[  219.187240]  [<ffffffff816ac048>] __netif_receive_skb+0x18/0x60
[  219.187242]  [<ffffffff816ad1ce>] process_backlog+0x9e/0x140
[  219.187243]  [<ffffffff816ac8ec>] net_rx_action+0x22c/0x370
[  219.187245]  [<ffffffff817cd352>] __do_softirq+0x112/0x2e7
[  219.187247]  [<ffffffff817cc3bc>] do_softirq_own_stack+0x1c/0x30
[  219.187247]  <EOI>
[  219.187248]  [<ffffffff810aa1c8>] do_softirq.part.14+0x38/0x40
[  219.187249]  [<ffffffff810aa24d>] __local_bh_enable_ip+0x7d/0x80
[  219.187254]  [<ffffffffa0408428>] sctp_inq_push+0x68/0x80 [sctp]
[  219.187258]  [<ffffffffa04190f1>] sctp_backlog_rcv+0x151/0x1c0 [sctp]
[  219.187260]  [<ffffffff81692b07>] __release_sock+0x87/0xf0
[  219.187261]  [<ffffffff81692ba0>] release_sock+0x30/0xa0
[  219.187265]  [<ffffffffa040e46d>] sctp_accept+0x17d/0x210 [sctp]
[  219.187266]  [<ffffffff810e7510>] ? prepare_to_wait_event+0xf0/0xf0
[  219.187268]  [<ffffffff8172d52c>] inet_accept+0x3c/0x130
[  219.187269]  [<ffffffff8168d7a3>] SYSC_accept4+0x103/0x210
[  219.187271]  [<ffffffff817ca2ba>] ? _raw_spin_unlock_bh+0x1a/0x20
[  219.187272]  [<ffffffff81692bfc>] ? release_sock+0x8c/0xa0
[  219.187276]  [<ffffffffa0413e22>] ? sctp_inet_listen+0x62/0x1b0 [sctp]
[  219.187277]  [<ffffffff8168f2d0>] SyS_accept+0x10/0x20

Fixes: 860fbbc3 ("sctp: prepare for socket backlog behavior change")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 486bdee0 ("sctp: add support for RPS and RFS")
saves skb->hash into sk->sk_rxhash so that the inet_* can
record it to flow table.

But sctp uses sock_common_recvmsg as .recvmsg instead
of inet_recvmsg, sock_common_recvmsg doesn't invoke
sock_rps_record_flow to record the flow. It may cause
that the receiver has no chances to record the flow if
it doesn't send msg or poll the socket.

So this patch fixes it by using inet_recvmsg as .recvmsg
in sctp.

Fixes: 486bdee0 ("sctp: add support for RPS and RFS")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch makes sctp support ipv6 nonlocal bind by adding
sp->inet.freebind and net->ipv6.sysctl.ip_nonlocal_bind
check in sctp_v6_available as what sctp did to support
ipv4 nonlocal bind (commit cdac4e07).
Reported-by: NShijoe George <spanjikk@redhat.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do not cache pointers into the skb linear segment across sk_filter.
The function call can trigger pskb_expand_head.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 90017acc ("sctp: Add GSO support") didn't register SCTP GSO
offloading for IPv6 and yet didn't put any restrictions on generating
GSO packets while in IPv6, which causes all IPv6 GSO'ed packets to be
silently dropped.

The fix is to properly register the offload this time.

Fixes: 90017acc ("sctp: Add GSO support")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit d46e416c missed to update some other places which checked for
the socket being TCP-style AND Established state, as Closing state has
some overlapping with the previous understanding of Established.

Without this fix, one of the effects is that some already queued rx
messages may not be readable anymore depending on how the association
teared down, and sending may also not be possible if peer initiated the
shutdown.

Also merge two if() blocks into one condition on sctp_sendmsg().

Cc: Xin Long <lucien.xin@gmail.com>
Fixes: d46e416c ("sctp: sctp should change socket state when shutdown is received")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently only read-only checks are performed up to the point on where
we check if peer is ECN capable, checks which we can avoid otherwise.
The flag ecn_ce_done is only used to perform this check once per
incoming packet, and nothing more.

Thus this patch moves the peer check up.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should not clear that flag when switching to a new skb from a GSO skb
because it would cause ECN processing to happen multiple times per GSO
skb, which is not wanted. Instead, let it be processed once per chunk.
That is, in other words, once per IP header available.

Fixes: 90017acc ("sctp: Add GSO support")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Identifying address family operations during rx path is not something
expensive but it's ugly to the eye to have it done multiple times,
specially when we already validated it during initial rx processing.

This patch takes advantage of the now shared sctp_input_cb and make the
pointer to the operations readily available.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SCTP will try to access original IP headers on sctp_recvmsg in order to
copy the addresses used. There are also other places that do similar access
to IP or even SCTP headers. But after 90017acc ("sctp: Add GSO
support") they aren't always there because they are only present in the
header skb.

SCTP handles the queueing of incoming data by cloning the incoming skb
and limiting to only the relevant payload. This clone has its cb updated
to something different and it's then queued on socket rx queue. Thus we
need to fix this in two moments.

For rx path, not related to socket queue yet, this patch uses a
partially copied sctp_input_cb to such GSO frags. This restores the
ability to access the headers for this part of the code.

Regarding the socket rx queue, it removes iif member from sctp_event and
also add a chunk pointer on it.

With these changes we're always able to reach the headers again.

The biggest change here is that now the sctp_chunk struct and the
original skb are only freed after the application consumed the buffer.
Note however that the original payload was already like this due to the
skb cloning.

For iif, SCTP's IPv4 code doesn't use it, so no change is necessary.
IPv6 now can fetch it directly from original's IPv6 CB as the original
skb is still accessible.

In the future we probably can simplify sctp_v*_skb_iif() stuff, as
sctp_v4_skb_iif() was called but it's return value not used, and now
it's not even called, but such cleanup is out of scope for this change.

Fixes: 90017acc ("sctp: Add GSO support")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The next patch needs 8 bytes in there. sctp_ulpevent has a hole due to
bad alignment; msg_flags is using 4 bytes while it actually uses only 2, so
we shrink it, and iif member (4 bytes) which can be easily fetched from
another place once the next patch is there, so we remove it and thus
creating space for 8 bytes.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We process input path in other files too and having access to it is
nice, so move it to a header where it's shared.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

prsctp PRIO policy is a policy to abandon lower priority chunks when
asoc doesn't have enough snd buffer, so that the current chunk with
higher priority can be queued successfully.

Similar to TTL/RTX policy, we will set the priority of the chunk to
prsctp_param with sinfo->sinfo_timetolive in sctp_set_prsctp_policy().
So if PRIO policy is enabled, msg->expire_at won't work.

asoc->sent_cnt_removable will record how many chunks can be checked to
remove. If priority policy is enabled, when the chunk is queued into
the out_queue, we will increase sent_cnt_removable. When the chunk is
moved to abandon_queue or dequeue and free, we will decrease
sent_cnt_removable.

In sctp_sendmsg, we will check if there is enough snd buffer for current
msg and if sent_cnt_removable is not 0. Then try to abandon chunks in
sctp_prune_prsctp when sendmsg from the retransmit/transmited queue, and
free chunks from out_queue in right order until the abandon+free size >
msg_len - sctp_wfree. For the abandon size, we have to wait until it
sends FORWARD TSN, receives the sack and the chunks are really freed.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

prsctp RTX policy is a policy to abandon chunks when they are
retransmitted beyond the max count.

This patch uses sent_count to count how many times one chunk has
been sent, and prsctp_param is the max rtx count, which is from
sinfo->sinfo_timetolive in sctp_set_prsctp_policy(). So similar
to TTL policy, if RTX policy is enabled, msg->expire_at won't
work.

Then in sctp_chunk_abandoned, this patch checks if chunk->sent_count
is bigger than chunk->prsctp_param to abandon this chunk.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

prsctp TTL policy is a policy to abandon chunks when they expire
at the specific time in local stack. It's similar with expires_at
in struct sctp_datamsg.

This patch uses sinfo->sinfo_timetolive to set the specific time for
TTL policy. sinfo->sinfo_timetolive is also used for msg->expires_at.
So if prsctp_enable or TTL policy is not enabled, msg->expires_at
still works as before.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds SCTP_PR_ASSOC_STATUS to sctp sockopt, which is used
to dump the prsctp statistics info from the asoc. The prsctp statistics
includes abandoned_sent/unsent from the asoc. abandoned_sent is the
count of the packets we drop packets from retransmit/transmited queue,
and abandoned_unsent is the count of the packets we drop from out_queue
according to the policy.

Note: another option for prsctp statistics dump described in rfc is
SCTP_PR_STREAM_STATUS, which is used to dump the prsctp statistics
info from each stream. But by now, linux doesn't yet have per stream
statistics info, it needs rfc6525 to be implemented. As the prsctp
statistics for each stream has to be based on per stream statistics,
we will delay it until rfc6525 is done in linux.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds SCTP_DEFAULT_PRINFO to sctp sockopt. It is used
to set/get sctp Partially Reliable Policies' default params,
which includes 3 policies (ttl, rtx, prio) and their values.

Still, if we set policy params in sndinfo, we will use the params
of sndinfo against chunks, instead of the default params.

In this patch, we will use 5-8bit of sp/asoc->default_flags
to store prsctp policies, and reuse asoc->default_timetolive
to store their values. It means if we enable and set prsctp
policy, prior ttl timeout in sctp will not work any more.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

According to section 4.5 of rfc7496, prsctp_enable should be per asoc.
We will add prsctp_enable to both asoc and ep, and replace the places
where it used net.sctp->prsctp_enable with asoc->prsctp_enable.

ep->prsctp_enable will be initialized with net.sctp->prsctp_enable, and
asoc->prsctp_enable will be initialized with ep->prsctp_enable. We can
also modify it's value through sockopt SCTP_PR_SUPPORTED.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we introduced GSO support, if using auth the auth chunk was being
left queued on the packet even after the final segment was generated.
Later on sctp_transmit_packet it calls sctp_packet_reset, which zeroed
the packet len while not accounting for this left-over. This caused more
space to be used the next packet due to the chunk still being queued,
but space which wasn't allocated as its size wasn't accounted.

The fix is to only queue it back when we know that we are going to
generate another segment.

Fixes: 90017acc ("sctp: Add GSO support")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit d46e416c ("sctp: sctp should change socket state when
shutdown is received") may set sk_state CLOSING in sctp_sock_migrate,
but inet_accept doesn't allow the sk_state other than ESTABLISHED/
CLOSED for sctp. So we will change sk_state to CLOSED, instead of
CLOSING, as actually sk is closed already there.

Fixes: d46e416c ("sctp: sctp should change socket state when shutdown is received")
Reported-by: NYe Xiaolong <xiaolong.ye@intel.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The functions inet_diag_msg_common_fill and inet_diag_msg_attrs_fill
seem to have been missed from the include/linux/inet_diag.h header
file. Add them to fix the following warnings:

net/ipv4/inet_diag.c:69:6: warning: symbol 'inet_diag_msg_common_fill' was not declared. Should it be static?
net/ipv4/inet_diag.c:108:5: warning: symbol 'inet_diag_msg_attrs_fill' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now sctp doesn't change socket state upon shutdown reception. It changes
just the assoc state, even though it's a TCP-style socket.

For some cases, if we really need to check sk->sk_state, it's necessary to
fix this issue, at least when we use ss or netstat to dump, we can get a
more exact information.

As an improvement, we will change sk->sk_state when we change asoc->state
to SHUTDOWN_RECEIVED, and also do it in sctp_shutdown to keep consistent
with sctp_close.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

size_t objects should be printed with %Z printf format.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is useful for debugging packet sizes.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SCTP has this pecualiarity that its packets cannot be just segmented to
(P)MTU. Its chunks must be contained in IP segments, padding respected.
So we can't just generate a big skb, set gso_size to the fragmentation
point and deliver it to IP layer.

This patch takes a different approach. SCTP will now build a skb as it
would be if it was received using GRO. That is, there will be a cover
skb with protocol headers and children ones containing the actual
segments, already segmented to a way that respects SCTP RFCs.

With that, we can tell skb_segment() to just split based on frag_list,
trusting its sizes are already in accordance.

This way SCTP can benefit from GSO and instead of passing several
packets through the stack, it can pass a single large packet.

v2:
- Added support for receiving GSO frames, as requested by Dave Miller.
- Clear skb->cb if packet is GSO (otherwise it's not used by SCTP)
- Added heuristics similar to what we have in TCP for not generating
  single GSO packets that fills cwnd.
v3:
- consider sctphdr size in skb_gso_transport_seglen()
- rebased due to 5c7cdf33 ("gso: Remove arbitrary checks for
  unsupported GSO")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is a preparation for the GSO one. In order to successfully
handle GSO packets on rx path we must not call skb_linearize, otherwise
it defeats any gain GSO may have had.

This patch thus delays as much as possible the call to skb_linearize,
leaving it to sctp_inq_pop() moment. For that the sanity checks
performed now know how to deal with fragments.

One positive side-effect of this is that if the socket is backlogged it
will have the chance of doing it on backlog processing instead of
during softirq.

With this move, it's evident that a check for non-linearity in
sctp_inq_pop was ineffective and is now removed. Note that a similar
check is performed a bit below this one.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>