Commit Graph

8 Commits

Author SHA1 Message Date
Jiri Slaby d19af0a764 kcm: fix /proc memory leak
Every open of /proc/net/kcm leaks 16 bytes of memory as is reported by
kmemleak:
unreferenced object 0xffff88059c0e3458 (size 192):
  comm "cat", pid 1401, jiffies 4294935742 (age 310.720s)
  hex dump (first 32 bytes):
    28 45 71 96 05 88 ff ff 00 10 00 00 00 00 00 00  (Eq.............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8156a2de>] kmem_cache_alloc_trace+0x16e/0x230
    [<ffffffff8162a479>] seq_open+0x79/0x1d0
    [<ffffffffa0578510>] kcm_seq_open+0x0/0x30 [kcm]
    [<ffffffff8162a479>] seq_open+0x79/0x1d0
    [<ffffffff8162a8cf>] __seq_open_private+0x2f/0xa0
    [<ffffffff81712548>] seq_open_net+0x38/0xa0
...

It is caused by a missing free in the ->release path. So fix it by
providing seq_release_net as the ->release method.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: cd6e111bf5 (kcm: Add statistics and proc interfaces)
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Tom Herbert <tom@herbertland.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-22 16:32:23 -04:00
WANG Cong f1971a2e03 kcm: fix a signedness in kcm_splice_read()
skb_splice_bits() returns int, kcm_splice_read() returns ssize_t,
both are signed.

We may need another patch to make them all ssize_t, but that
deserves a separated patch.

Fixes: 91687355b9 ("kcm: Splice support")
Reported-by: David Binderman <linuxdev.baldrick@gmail.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-19 11:26:51 -07:00
Tom Herbert 29152a34f7 kcm: Add receive message timeout
This patch adds receive timeout for message assembly on the attached TCP
sockets. The timeout is set when a new messages is started and the whole
message has not been received by TCP (not in the receive queue). If the
completely message is subsequently received the timer is cancelled, if the
timer expires the RX side is aborted.

The timeout value is taken from the socket timeout (SO_RCVTIMEO) that is
set on a TCP socket (i.e. set by get sockopt before attaching a TCP socket
to KCM.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:15 -05:00
Tom Herbert 7ced95ef52 kcm: Add memory limit for receive message construction
Message assembly is performed on the TCP socket. This is logically
equivalent of an application that performs a peek on the socket to find
out how much memory is needed for a receive buffer. The receive socket
buffer also provides the maximum message size which is checked.

The receive algorithm is something like:

   1) Receive the first skbuf for a message (or skbufs if multiple are
      needed to determine message length).
   2) Check the message length against the number of bytes in the TCP
      receive queue (tcp_inq()).
	- If all the bytes of the message are in the queue (incluing the
	  skbuf received), then proceed with message assembly (it should
	  complete with the tcp_read_sock)
        - Else, mark the psock with the number of bytes needed to
	  complete the message.
   3) In TCP data ready function, if the psock indicates that we are
      waiting for the rest of the bytes of a messages, check the number
      of queued bytes against that.
        - If there are still not enough bytes for the message, just
	  return
        - Else, clear the waiting bytes and proceed to receive the
	  skbufs.  The message should now be received in one
	  tcp_read_sock

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:15 -05:00
Tom Herbert f29698fc6b kcm: Sendpage support
Implement kcm_sendpage. Set in sendpage to kcm_sendpage in both
dgram and seqpacket ops.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:15 -05:00
Tom Herbert 91687355b9 kcm: Splice support
Implement kcm_splice_read. This is supported only for seqpacket.
Add kcm_seqpacket_ops and set splice read to kcm_splice_read.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:15 -05:00
Tom Herbert cd6e111bf5 kcm: Add statistics and proc interfaces
This patch adds various counters for KCM. These include counters for
messages and bytes received or sent, as well as counters for number of
attached/unattached TCP sockets and other error or edge events.

The statistics are exposed via a proc interface. /proc/net/kcm provides
statistics per KCM socket and per psock (attached TCP sockets).
/proc/net/kcm_stats provides aggregate statistics.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:14 -05:00
Tom Herbert ab7ac4eb98 kcm: Kernel Connection Multiplexor module
This module implements the Kernel Connection Multiplexor.

Kernel Connection Multiplexor (KCM) is a facility that provides a
message based interface over TCP for generic application protocols.
With KCM an application can efficiently send and receive application
protocol messages over TCP using datagram sockets.

For more information see the included Documentation/networking/kcm.txt

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-09 16:36:14 -05:00