diff options
Diffstat (limited to 'net/ipv4/tcp_probe.c')
| -rw-r--r-- | net/ipv4/tcp_probe.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/net/ipv4/tcp_probe.c b/net/ipv4/tcp_probe.c new file mode 100644 index 00000000000..d7d517a3a23 --- /dev/null +++ b/net/ipv4/tcp_probe.c @@ -0,0 +1,181 @@ +/* + * tcpprobe - Observe the TCP flow with kprobes. + * + * The idea for this came from Werner Almesberger's umlsim + * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org> + * + * 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/tcp.h> +#include <linux/proc_fs.h> +#include <linux/module.h> +#include <linux/kfifo.h> +#include <linux/vmalloc.h> + +#include <net/tcp.h> + +MODULE_AUTHOR("Stephen Hemminger <shemminger@osdl.org>"); +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 ", + (unsigned long) now.tv_sec, + (unsigned long) 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); |