/* * dccp_probe - Observe the DCCP flow with kprobes. * * The idea for this came from Werner Almesberger's umlsim * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org> * * Modified for DCCP from Stephen Hemminger's code * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz> * * 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/dccp.h> #include <linux/proc_fs.h> #include <linux/module.h> #include <linux/kfifo.h> #include <linux/vmalloc.h> #include <linux/gfp.h> #include <net/net_namespace.h> #include "dccp.h" #include "ccid.h" #include "ccids/ccid3.h" static int port; static int bufsize = 64 * 1024; static const char procname[] = "dccpprobe"; static struct { struct kfifo fifo; spinlock_t lock; wait_queue_head_t wait; struct timespec tstart; } dccpw; static void printl(const char *fmt, ...) { va_list args; int len; struct timespec now; char tbuf[256]; va_start(args, fmt); getnstimeofday(&now); now = timespec_sub(now, dccpw.tstart); len = sprintf(tbuf, "%lu.%06lu ", (unsigned long) now.tv_sec, (unsigned long) now.tv_nsec / NSEC_PER_USEC); len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); va_end(args); kfifo_in_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); wake_up(&dccpw.wait); } static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, size_t size) { const struct inet_sock *inet = inet_sk(sk); struct ccid3_hc_tx_sock *hc = NULL; if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3) hc = ccid3_hc_tx_sk(sk); if (port == 0 || ntohs(inet->inet_dport) == port || ntohs(inet->inet_sport) == port) { if (hc) printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n", &inet->inet_saddr, ntohs(inet->inet_sport), &inet->inet_daddr, ntohs(inet->inet_dport), size, hc->tx_s, hc->tx_rtt, hc->tx_p, hc->tx_x_calc, hc->tx_x_recv >> 6, hc->tx_x >> 6, hc->tx_t_ipi); else printl("%pI4:%u %pI4:%u %d\n", &inet->inet_saddr, ntohs(inet->inet_sport), &inet->inet_daddr, ntohs(inet->inet_dport), size); } jprobe_return(); return 0; } static struct jprobe dccp_send_probe = { .kp = { .symbol_name = "dccp_sendmsg", }, .entry = jdccp_sendmsg, }; static int dccpprobe_open(struct inode *inode, struct file *file) { kfifo_reset(&dccpw.fifo); getnstimeofday(&dccpw.tstart); return 0; } static ssize_t dccpprobe_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(dccpw.wait, kfifo_len(&dccpw.fifo) != 0); if (error) goto out_free; cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0; out_free: vfree(tbuf); return error ? error : cnt; } static const struct file_operations dccpprobe_fops = { .owner = THIS_MODULE, .open = dccpprobe_open, .read = dccpprobe_read, }; static __init int dccpprobe_init(void) { int ret = -ENOMEM; init_waitqueue_head(&dccpw.wait); spin_lock_init(&dccpw.lock); if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL)) return ret; if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops)) goto err0; try_then_request_module((ret = register_jprobe(&dccp_send_probe)) == 0, "dccp"); if (ret) goto err1; pr_info("DCCP watch registered (port=%d)\n", port); return 0; err1: proc_net_remove(&init_net, procname); err0: kfifo_free(&dccpw.fifo); return ret; } module_init(dccpprobe_init); static __exit void dccpprobe_exit(void) { kfifo_free(&dccpw.fifo); proc_net_remove(&init_net, procname); unregister_jprobe(&dccp_send_probe); } module_exit(dccpprobe_exit); MODULE_PARM_DESC(port, "Port to match (0=all)"); module_param(port, int, 0); MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); module_param(bufsize, int, 0); MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>"); MODULE_DESCRIPTION("DCCP snooper"); MODULE_LICENSE("GPL");