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85795d64ed
Change tcp_probe to use ktime (needed to add one export). Add option to only get events when cwnd changes - from Doug Leith Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
197 lines
4.8 KiB
C
197 lines
4.8 KiB
C
/*
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* tcpprobe - Observe the TCP flow with kprobes.
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*
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* The idea for this came from Werner Almesberger's umlsim
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* Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/socket.h>
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#include <linux/tcp.h>
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#include <linux/proc_fs.h>
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#include <linux/module.h>
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#include <linux/kfifo.h>
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#include <linux/ktime.h>
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#include <linux/time.h>
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#include <linux/vmalloc.h>
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#include <net/tcp.h>
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MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
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MODULE_DESCRIPTION("TCP cwnd snooper");
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MODULE_LICENSE("GPL");
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static int port __read_mostly = 0;
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MODULE_PARM_DESC(port, "Port to match (0=all)");
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module_param(port, int, 0);
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static int bufsize __read_mostly = 64*1024;
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MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
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module_param(bufsize, int, 0);
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static int full __read_mostly;
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MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
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module_param(full, int, 0);
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static const char procname[] = "tcpprobe";
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struct {
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struct kfifo *fifo;
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spinlock_t lock;
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wait_queue_head_t wait;
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ktime_t start;
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u32 lastcwnd;
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} tcpw;
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/*
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* Print to log with timestamps.
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* FIXME: causes an extra copy
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*/
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static void printl(const char *fmt, ...)
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{
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va_list args;
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int len;
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struct timespec tv;
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char tbuf[256];
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va_start(args, fmt);
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/* want monotonic time since start of tcp_probe */
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tv = ktime_to_timespec(ktime_sub(ktime_get(), tcpw.start));
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len = sprintf(tbuf, "%lu.%09lu ",
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(unsigned long) tv.tv_sec, (unsigned long) tv.tv_nsec);
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len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
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va_end(args);
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kfifo_put(tcpw.fifo, tbuf, len);
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wake_up(&tcpw.wait);
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}
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/*
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* Hook inserted to be called before each receive packet.
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* Note: arguments must match tcp_rcv_established()!
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*/
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static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
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struct tcphdr *th, unsigned len)
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{
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const struct tcp_sock *tp = tcp_sk(sk);
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const struct inet_sock *inet = inet_sk(sk);
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/* Only update if port matches */
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if ((port == 0 || ntohs(inet->dport) == port || ntohs(inet->sport) == port)
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&& (full || tp->snd_cwnd != tcpw.lastcwnd)) {
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printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %#x %#x %u %u %u\n",
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NIPQUAD(inet->saddr), ntohs(inet->sport),
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NIPQUAD(inet->daddr), ntohs(inet->dport),
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skb->len, tp->snd_nxt, tp->snd_una,
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tp->snd_cwnd, tcp_current_ssthresh(sk),
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tp->snd_wnd, tp->srtt >> 3);
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tcpw.lastcwnd = tp->snd_cwnd;
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}
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jprobe_return();
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return 0;
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}
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static struct jprobe tcp_probe = {
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.kp = {
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.symbol_name = "tcp_rcv_established",
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},
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.entry = JPROBE_ENTRY(jtcp_rcv_established),
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};
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static int tcpprobe_open(struct inode * inode, struct file * file)
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{
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kfifo_reset(tcpw.fifo);
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tcpw.start = ktime_get();
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return 0;
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}
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static ssize_t tcpprobe_read(struct file *file, char __user *buf,
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size_t len, loff_t *ppos)
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{
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int error = 0, cnt = 0;
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unsigned char *tbuf;
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if (!buf || len < 0)
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return -EINVAL;
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if (len == 0)
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return 0;
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tbuf = vmalloc(len);
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if (!tbuf)
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return -ENOMEM;
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error = wait_event_interruptible(tcpw.wait,
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__kfifo_len(tcpw.fifo) != 0);
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if (error)
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goto out_free;
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cnt = kfifo_get(tcpw.fifo, tbuf, len);
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error = copy_to_user(buf, tbuf, cnt);
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out_free:
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vfree(tbuf);
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return error ? error : cnt;
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}
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static const struct file_operations tcpprobe_fops = {
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.owner = THIS_MODULE,
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.open = tcpprobe_open,
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.read = tcpprobe_read,
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};
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static __init int tcpprobe_init(void)
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{
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int ret = -ENOMEM;
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init_waitqueue_head(&tcpw.wait);
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spin_lock_init(&tcpw.lock);
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tcpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &tcpw.lock);
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if (IS_ERR(tcpw.fifo))
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return PTR_ERR(tcpw.fifo);
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if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))
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goto err0;
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ret = register_jprobe(&tcp_probe);
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if (ret)
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goto err1;
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pr_info("TCP watch registered (port=%d)\n", port);
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return 0;
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err1:
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proc_net_remove(procname);
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err0:
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kfifo_free(tcpw.fifo);
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return ret;
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}
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module_init(tcpprobe_init);
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static __exit void tcpprobe_exit(void)
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{
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kfifo_free(tcpw.fifo);
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proc_net_remove(procname);
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unregister_jprobe(&tcp_probe);
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}
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module_exit(tcpprobe_exit);
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