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/*
* 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/socket.h>
#include <linux/sctp.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.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 __printf(1, 2) 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,
.llseek = noop_llseek,
};
static sctp_disposition_t jsctp_sf_eat_sack(struct net *net,
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("*");
printl("%pISc %2u %8u %8u %8u %8u %8u ",
&sp->ipaddr, 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;
/* Warning: if the function signature of sctp_sf_eat_sack_6_2,
* has been changed, you also have to change the signature of
* jsctp_sf_eat_sack, otherwise you end up right here!
*/
BUILD_BUG_ON(__same_type(sctp_sf_eat_sack_6_2,
jsctp_sf_eat_sack) == 0);
init_waitqueue_head(&sctpw.wait);
spin_lock_init(&sctpw.lock);
if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
return ret;
if (!proc_create(procname, S_IRUSR, init_net.proc_net,
&sctpprobe_fops))
goto free_kfifo;
ret = register_jprobe(&sctp_recv_probe);
if (ret)
goto remove_proc;
pr_info("probe registered (port=%d)\n", port);
return 0;
remove_proc:
remove_proc_entry(procname, init_net.proc_net);
free_kfifo:
kfifo_free(&sctpw.fifo);
return ret;
}
static __exit void sctpprobe_exit(void)
{
kfifo_free(&sctpw.fifo);
remove_proc_entry(procname, init_net.proc_net);
unregister_jprobe(&sctp_recv_probe);
}
module_init(sctpprobe_init);
module_exit(sctpprobe_exit);
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