sctp: implement sctp association probing module

This patch implement sctp association probing module, the module
will be called sctp_probe.

This module allows for capturing the changes to SCTP association
state in response to incoming packets. It is used for debugging
SCTP congestion control algorithms.

Usage:
  $ modprobe sctp_probe [full=n] [port=n] [bufsize=n]
  $ cat /proc/net/sctpprobe

  The output format is:
    TIME     ASSOC     LPORT RPORT MTU    RWND  UNACK <REMOTE-ADDR   STATE  CWND   SSTHRESH  INFLIGHT  PARTIAL_BYTES_ACKED MTU> ...

  The output will be like this:
    9.226086 c4064c48  9000  8000  1500    53352     1 *192.168.0.19  1     4380    54784     1252        0     1500
    9.287195 c4064c48  9000  8000  1500    45144     5 *192.168.0.19  1     5880    54784     6500        0     1500
    9.289130 c4064c48  9000  8000  1500    42724     5 *192.168.0.19  1     7380    54784     6500        0     1500
    9.620332 c4064c48  9000  8000  1500    48284     4 *192.168.0.19  1     8880    54784     5200        0     1500
    ......

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
diff --git a/net/sctp/Makefile b/net/sctp/Makefile
index 6b79473..5c30b7a 100644
--- a/net/sctp/Makefile
+++ b/net/sctp/Makefile
@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_IP_SCTP) += sctp.o
+obj-$(CONFIG_NET_SCTPPROBE) += sctp_probe.o
 
 sctp-y := sm_statetable.o sm_statefuns.o sm_sideeffect.o \
 	  protocol.o endpointola.o associola.o \
@@ -11,6 +12,8 @@
 	  tsnmap.o bind_addr.o socket.o primitive.o \
 	  output.o input.o debug.o ssnmap.o auth.o
 
+sctp_probe-y := probe.o
+
 sctp-$(CONFIG_SCTP_DBG_OBJCNT) += objcnt.o
 sctp-$(CONFIG_PROC_FS) += proc.o
 sctp-$(CONFIG_SYSCTL) += sysctl.o