From a42e9d6ce89cfd19aee9f990b7231ce697f0d00f Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 5 Jun 2006 17:30:32 -0700 Subject: [TCP]: TCP Probe congestion window tracing This adds a new module for tracking TCP state variables non-intrusively using kprobes. It has a simple /proc interface that outputs one line for each packet received. A sample usage is to collect congestion window and ssthresh over time graphs. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/tcp_probe.c | 179 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 179 insertions(+) create mode 100644 net/ipv4/tcp_probe.c (limited to 'net/ipv4/tcp_probe.c') diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c new file mode 100644 index 00000000000..be94d526c7c --- /dev/null +++ b/net/ipv4/tcp_probe.c @@ -0,0 +1,179 @@ +/* + * tcpprobe - Observe the TCP flow with kprobes. + * + * The idea for this came from Werner Almesberger's umlsim + * Copyright (C) 2004, Stephen Hemminger + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +#include + +MODULE_AUTHOR("Stephen Hemminger "); +MODULE_DESCRIPTION("TCP cwnd snooper"); +MODULE_LICENSE("GPL"); + +static int port = 0; +MODULE_PARM_DESC(port, "Port to match (0=all)"); +module_param(port, int, 0); + +static int bufsize = 64*1024; +MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); +module_param(bufsize, int, 0); + +static const char procname[] = "tcpprobe"; + +struct { + struct kfifo *fifo; + spinlock_t lock; + wait_queue_head_t wait; + struct timeval tstart; +} tcpw; + +static void printl(const char *fmt, ...) +{ + va_list args; + int len; + struct timeval now; + char tbuf[256]; + + va_start(args, fmt); + do_gettimeofday(&now); + + now.tv_sec -= tcpw.tstart.tv_sec; + now.tv_usec -= tcpw.tstart.tv_usec; + if (now.tv_usec < 0) { + --now.tv_sec; + now.tv_usec += 1000000; + } + + len = sprintf(tbuf, "%lu.%06lu ", now.tv_sec, now.tv_usec); + len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); + va_end(args); + + kfifo_put(tcpw.fifo, tbuf, len); + wake_up(&tcpw.wait); +} + +static int jtcp_sendmsg(struct kiocb *iocb, struct sock *sk, + struct msghdr *msg, size_t size) +{ + const struct tcp_sock *tp = tcp_sk(sk); + const struct inet_sock *inet = inet_sk(sk); + + if (port == 0 || ntohs(inet->dport) == port || + ntohs(inet->sport) == port) { + printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %#x %#x %u %u %u\n", + NIPQUAD(inet->saddr), ntohs(inet->sport), + NIPQUAD(inet->daddr), ntohs(inet->dport), + size, tp->snd_nxt, tp->snd_una, + tp->snd_cwnd, tcp_current_ssthresh(sk), + tp->snd_wnd); + } + + jprobe_return(); + return 0; +} + +static struct jprobe tcp_send_probe = { + .kp = { .addr = (kprobe_opcode_t *) &tcp_sendmsg, }, + .entry = (kprobe_opcode_t *) &jtcp_sendmsg, +}; + + +static int tcpprobe_open(struct inode * inode, struct file * file) +{ + kfifo_reset(tcpw.fifo); + do_gettimeofday(&tcpw.tstart); + return 0; +} + +static ssize_t tcpprobe_read(struct file *file, char __user *buf, + size_t len, loff_t *ppos) +{ + int error = 0, cnt; + unsigned char *tbuf; + + if (!buf || len < 0) + return -EINVAL; + + if (len == 0) + return 0; + + tbuf = vmalloc(len); + if (!tbuf) + return -ENOMEM; + + error = wait_event_interruptible(tcpw.wait, + __kfifo_len(tcpw.fifo) != 0); + if (error) + return error; + + cnt = kfifo_get(tcpw.fifo, tbuf, len); + error = copy_to_user(buf, tbuf, cnt); + + vfree(tbuf); + + return error ? error : cnt; +} + +static struct file_operations tcpprobe_fops = { + .owner = THIS_MODULE, + .open = tcpprobe_open, + .read = tcpprobe_read, +}; + +static __init int tcpprobe_init(void) +{ + int ret = -ENOMEM; + + init_waitqueue_head(&tcpw.wait); + spin_lock_init(&tcpw.lock); + tcpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &tcpw.lock); + + if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops)) + goto err0; + + ret = register_jprobe(&tcp_send_probe); + if (ret) + goto err1; + + pr_info("TCP watch registered (port=%d)\n", port); + return 0; + err1: + proc_net_remove(procname); + err0: + kfifo_free(tcpw.fifo); + return ret; +} +module_init(tcpprobe_init); + +static __exit void tcpprobe_exit(void) +{ + kfifo_free(tcpw.fifo); + proc_net_remove(procname); + unregister_jprobe(&tcp_send_probe); + +} +module_exit(tcpprobe_exit); -- cgit v1.2.3-70-g09d2 From 70df2311ee3fc607e7511873d7dade5bd17d593d Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Mon, 5 Jun 2006 17:59:20 -0700 Subject: [TCP]: Fix compile warning in tcp_probe.c The suseconds_t et al. are not necessarily any particular type on every platform, so cast to unsigned long so that we can use one printf format string and avoid warnings across the board Signed-off-by: David S. Miller --- net/ipv4/tcp_probe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/ipv4/tcp_probe.c') diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c index be94d526c7c..d7d517a3a23 100644 --- a/net/ipv4/tcp_probe.c +++ b/net/ipv4/tcp_probe.c @@ -68,7 +68,9 @@ static void printl(const char *fmt, ...) now.tv_usec += 1000000; } - len = sprintf(tbuf, "%lu.%06lu ", now.tv_sec, now.tv_usec); + len = sprintf(tbuf, "%lu.%06lu ", + (unsigned long) now.tv_sec, + (unsigned long) now.tv_usec); len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); va_end(args); -- cgit v1.2.3-70-g09d2