Commit 787a51a0 authored by Wei Yongjun's avatar Wei Yongjun Committed by Vlad Yasevich
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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: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
parent ec7b9519

net/sctp/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -37,6 +37,18 @@ menuconfig IP_SCTP 


if IP_SCTP



config NET_SCTPPROBE

	tristate "SCTP: Association probing"

        depends on PROC_FS && KPROBES

        ---help---

        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. If you don't understand

        what was just said, you don't need it: say N.



        To compile this code as a module, choose M here: the

        module will be called sctp_probe.



config SCTP_DBG_MSG

	bool "SCTP: Debug messages"

	help

net/sctp/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -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 @@ sctp-y := sm_statetable.o sm_statefuns.o sm_sideeffect.o \ 
	  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

net/sctp/probe.c

0 → 100644
+213 −0
Original line number Diff line number Diff line 
/*

 * sctp_probe - Observe the SCTP flow with kprobes.

 *

 * The idea for this came from Werner Almesberger's umlsim

 * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>

 *

 * Modified for SCTP from Stephen Hemminger's code

 * Copyright (C) 2010, Wei Yongjun <yjwei@cn.fujitsu.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 */



#include <linux/kernel.h>

#include <linux/kprobes.h>

#include <linux/socket.h>

#include <linux/sctp.h>

#include <linux/proc_fs.h>

#include <linux/module.h>

#include <linux/kfifo.h>

#include <linux/time.h>

#include <net/net_namespace.h>



#include <net/sctp/sctp.h>

#include <net/sctp/sm.h>



MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");

MODULE_DESCRIPTION("SCTP snooper");

MODULE_LICENSE("GPL");



static int port __read_mostly = 0;

MODULE_PARM_DESC(port, "Port to match (0=all)");

module_param(port, int, 0);



static int bufsize __read_mostly = 64 * 1024;

MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");

module_param(bufsize, int, 0);



static int full __read_mostly = 1;

MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");

module_param(full, int, 0);



static const char procname[] = "sctpprobe";



static struct {

	struct kfifo	  fifo;

	spinlock_t	  lock;

	wait_queue_head_t wait;

	struct timespec	  tstart;

} sctpw;



static void printl(const char *fmt, ...)

{

	va_list args;

	int len;

	char tbuf[256];



	va_start(args, fmt);

	len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);

	va_end(args);



	kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);

	wake_up(&sctpw.wait);

}



static int sctpprobe_open(struct inode *inode, struct file *file)

{

	kfifo_reset(&sctpw.fifo);

	getnstimeofday(&sctpw.tstart);



	return 0;

}



static ssize_t sctpprobe_read(struct file *file, char __user *buf,

			      size_t len, loff_t *ppos)

{

	int error = 0, cnt = 0;

	unsigned char *tbuf;



	if (!buf)

		return -EINVAL;



	if (len == 0)

		return 0;



	tbuf = vmalloc(len);

	if (!tbuf)

		return -ENOMEM;



	error = wait_event_interruptible(sctpw.wait,

					 kfifo_len(&sctpw.fifo) != 0);

	if (error)

		goto out_free;



	cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);

	error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;



out_free:

	vfree(tbuf);



	return error ? error : cnt;

}



static const struct file_operations sctpprobe_fops = {

	.owner	= THIS_MODULE,

	.open	= sctpprobe_open,

	.read	= sctpprobe_read,

};



sctp_disposition_t jsctp_sf_eat_sack(const struct sctp_endpoint *ep,

				     const struct sctp_association *asoc,

				     const sctp_subtype_t type,

				     void *arg,

				     sctp_cmd_seq_t *commands)

{

	struct sctp_transport *sp;

	static __u32 lcwnd = 0;

	struct timespec now;



	sp = asoc->peer.primary_path;



	if ((full || sp->cwnd != lcwnd) &&

	    (!port || asoc->peer.port == port ||

	     ep->base.bind_addr.port == port)) {

		lcwnd = sp->cwnd;



		getnstimeofday(&now);

		now = timespec_sub(now, sctpw.tstart);



		printl("%lu.%06lu ", (unsigned long) now.tv_sec,

		       (unsigned long) now.tv_nsec / NSEC_PER_USEC);



		printl("%p %5d %5d %5d %8d %5d ", asoc,

		       ep->base.bind_addr.port, asoc->peer.port,

		       asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);



		list_for_each_entry(sp, &asoc->peer.transport_addr_list,

					transports) {

			if (sp == asoc->peer.primary_path)

				printl("*");



			if (sp->ipaddr.sa.sa_family == AF_INET)

				printl("%pI4 ", &sp->ipaddr.v4.sin_addr);

			else

				printl("%pI6 ", &sp->ipaddr.v6.sin6_addr);



			printl("%2u %8u %8u %8u %8u %8u ",

			       sp->state, sp->cwnd, sp->ssthresh,

			       sp->flight_size, sp->partial_bytes_acked,

			       sp->pathmtu);

		}

		printl("\n");

	}



	jprobe_return();

	return 0;

}



static struct jprobe sctp_recv_probe = {

	.kp	= {

		.symbol_name = "sctp_sf_eat_sack_6_2",

	},

	.entry	= jsctp_sf_eat_sack,

};



static __init int sctpprobe_init(void)

{

	int ret = -ENOMEM;



	init_waitqueue_head(&sctpw.wait);

	spin_lock_init(&sctpw.lock);

	if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))

		return ret;



	if (!proc_net_fops_create(&init_net, procname, S_IRUSR,

				  &sctpprobe_fops))

		goto free_kfifo;



	ret = register_jprobe(&sctp_recv_probe);

	if (ret)

		goto remove_proc;



	pr_info("SCTP probe registered (port=%d)\n", port);



	return 0;



remove_proc:

	proc_net_remove(&init_net, procname);

free_kfifo:

	kfifo_free(&sctpw.fifo);

	return ret;

}



static __exit void sctpprobe_exit(void)

{

	kfifo_free(&sctpw.fifo);

	proc_net_remove(&init_net, procname);

	unregister_jprobe(&sctp_recv_probe);

}



module_init(sctpprobe_init);

module_exit(sctpprobe_exit);

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