1/* 2 * dccp_probe - Observe the DCCP flow with kprobes. 3 * 4 * The idea for this came from Werner Almesberger's umlsim 5 * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org> 6 * 7 * Modified for DCCP from Stephen Hemminger's code 8 * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 23 */ 24 25#include <linux/kernel.h> 26#include <linux/kprobes.h> 27#include <linux/socket.h> 28#include <linux/dccp.h> 29#include <linux/proc_fs.h> 30#include <linux/module.h> 31#include <linux/kfifo.h> 32#include <linux/vmalloc.h> 33#include <linux/gfp.h> 34#include <net/net_namespace.h> 35 36#include "dccp.h" 37#include "ccid.h" 38#include "ccids/ccid3.h" 39 40static int port; 41 42static int bufsize = 64 * 1024; 43 44static const char procname[] = "dccpprobe"; 45 46static struct { 47 struct kfifo fifo; 48 spinlock_t lock; 49 wait_queue_head_t wait; 50 struct timespec tstart; 51} dccpw; 52 53static void printl(const char *fmt, ...) 54{ 55 va_list args; 56 int len; 57 struct timespec now; 58 char tbuf[256]; 59 60 va_start(args, fmt); 61 getnstimeofday(&now); 62 63 now = timespec_sub(now, dccpw.tstart); 64 65 len = sprintf(tbuf, "%lu.%06lu ", 66 (unsigned long) now.tv_sec, 67 (unsigned long) now.tv_nsec / NSEC_PER_USEC); 68 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); 69 va_end(args); 70 71 kfifo_in_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); 72 wake_up(&dccpw.wait); 73} 74 75static int jdccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) 76{ 77 const struct inet_sock *inet = inet_sk(sk); 78 struct ccid3_hc_tx_sock *hc = NULL; 79 80 if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3) 81 hc = ccid3_hc_tx_sk(sk); 82 83 if (port == 0 || ntohs(inet->inet_dport) == port || 84 ntohs(inet->inet_sport) == port) { 85 if (hc) 86 printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n", 87 &inet->inet_saddr, ntohs(inet->inet_sport), 88 &inet->inet_daddr, ntohs(inet->inet_dport), size, 89 hc->tx_s, hc->tx_rtt, hc->tx_p, 90 hc->tx_x_calc, hc->tx_x_recv >> 6, 91 hc->tx_x >> 6, hc->tx_t_ipi); 92 else 93 printl("%pI4:%u %pI4:%u %d\n", 94 &inet->inet_saddr, ntohs(inet->inet_sport), 95 &inet->inet_daddr, ntohs(inet->inet_dport), 96 size); 97 } 98 99 jprobe_return(); 100 return 0; 101} 102 103static struct jprobe dccp_send_probe = { 104 .kp = { 105 .symbol_name = "dccp_sendmsg", 106 }, 107 .entry = jdccp_sendmsg, 108}; 109 110static int dccpprobe_open(struct inode *inode, struct file *file) 111{ 112 kfifo_reset(&dccpw.fifo); 113 getnstimeofday(&dccpw.tstart); 114 return 0; 115} 116 117static ssize_t dccpprobe_read(struct file *file, char __user *buf, 118 size_t len, loff_t *ppos) 119{ 120 int error = 0, cnt = 0; 121 unsigned char *tbuf; 122 123 if (!buf) 124 return -EINVAL; 125 126 if (len == 0) 127 return 0; 128 129 tbuf = vmalloc(len); 130 if (!tbuf) 131 return -ENOMEM; 132 133 error = wait_event_interruptible(dccpw.wait, 134 kfifo_len(&dccpw.fifo) != 0); 135 if (error) 136 goto out_free; 137 138 cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); 139 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0; 140 141out_free: 142 vfree(tbuf); 143 144 return error ? error : cnt; 145} 146 147static const struct file_operations dccpprobe_fops = { 148 .owner = THIS_MODULE, 149 .open = dccpprobe_open, 150 .read = dccpprobe_read, 151 .llseek = noop_llseek, 152}; 153 154static __init int dccpprobe_init(void) 155{ 156 int ret = -ENOMEM; 157 158 init_waitqueue_head(&dccpw.wait); 159 spin_lock_init(&dccpw.lock); 160 if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL)) 161 return ret; 162 if (!proc_create(procname, S_IRUSR, init_net.proc_net, &dccpprobe_fops)) 163 goto err0; 164 165 ret = register_jprobe(&dccp_send_probe); 166 if (ret) { 167 ret = request_module("dccp"); 168 if (!ret) 169 ret = register_jprobe(&dccp_send_probe); 170 } 171 172 if (ret) 173 goto err1; 174 175 pr_info("DCCP watch registered (port=%d)\n", port); 176 return 0; 177err1: 178 remove_proc_entry(procname, init_net.proc_net); 179err0: 180 kfifo_free(&dccpw.fifo); 181 return ret; 182} 183module_init(dccpprobe_init); 184 185static __exit void dccpprobe_exit(void) 186{ 187 kfifo_free(&dccpw.fifo); 188 remove_proc_entry(procname, init_net.proc_net); 189 unregister_jprobe(&dccp_send_probe); 190 191} 192module_exit(dccpprobe_exit); 193 194MODULE_PARM_DESC(port, "Port to match (0=all)"); 195module_param(port, int, 0); 196 197MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); 198module_param(bufsize, int, 0); 199 200MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>"); 201MODULE_DESCRIPTION("DCCP snooper"); 202MODULE_LICENSE("GPL"); 203