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 kiocb *iocb, struct sock *sk, 76 struct msghdr *msg, size_t size) 77{ 78 const struct inet_sock *inet = inet_sk(sk); 79 struct ccid3_hc_tx_sock *hc = NULL; 80 81 if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3) 82 hc = ccid3_hc_tx_sk(sk); 83 84 if (port == 0 || ntohs(inet->inet_dport) == port || 85 ntohs(inet->inet_sport) == port) { 86 if (hc) 87 printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n", 88 &inet->inet_saddr, ntohs(inet->inet_sport), 89 &inet->inet_daddr, ntohs(inet->inet_dport), size, 90 hc->tx_s, hc->tx_rtt, hc->tx_p, 91 hc->tx_x_calc, hc->tx_x_recv >> 6, 92 hc->tx_x >> 6, hc->tx_t_ipi); 93 else 94 printl("%pI4:%u %pI4:%u %d\n", 95 &inet->inet_saddr, ntohs(inet->inet_sport), 96 &inet->inet_daddr, ntohs(inet->inet_dport), 97 size); 98 } 99 100 jprobe_return(); 101 return 0; 102} 103 104static struct jprobe dccp_send_probe = { 105 .kp = { 106 .symbol_name = "dccp_sendmsg", 107 }, 108 .entry = jdccp_sendmsg, 109}; 110 111static int dccpprobe_open(struct inode *inode, struct file *file) 112{ 113 kfifo_reset(&dccpw.fifo); 114 getnstimeofday(&dccpw.tstart); 115 return 0; 116} 117 118static ssize_t dccpprobe_read(struct file *file, char __user *buf, 119 size_t len, loff_t *ppos) 120{ 121 int error = 0, cnt = 0; 122 unsigned char *tbuf; 123 124 if (!buf) 125 return -EINVAL; 126 127 if (len == 0) 128 return 0; 129 130 tbuf = vmalloc(len); 131 if (!tbuf) 132 return -ENOMEM; 133 134 error = wait_event_interruptible(dccpw.wait, 135 kfifo_len(&dccpw.fifo) != 0); 136 if (error) 137 goto out_free; 138 139 cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock); 140 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0; 141 142out_free: 143 vfree(tbuf); 144 145 return error ? error : cnt; 146} 147 148static const struct file_operations dccpprobe_fops = { 149 .owner = THIS_MODULE, 150 .open = dccpprobe_open, 151 .read = dccpprobe_read, 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_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops)) 163 goto err0; 164 165 try_then_request_module((ret = register_jprobe(&dccp_send_probe)) == 0, 166 "dccp"); 167 if (ret) 168 goto err1; 169 170 pr_info("DCCP watch registered (port=%d)\n", port); 171 return 0; 172err1: 173 proc_net_remove(&init_net, procname); 174err0: 175 kfifo_free(&dccpw.fifo); 176 return ret; 177} 178module_init(dccpprobe_init); 179 180static __exit void dccpprobe_exit(void) 181{ 182 kfifo_free(&dccpw.fifo); 183 proc_net_remove(&init_net, procname); 184 unregister_jprobe(&dccp_send_probe); 185 186} 187module_exit(dccpprobe_exit); 188 189MODULE_PARM_DESC(port, "Port to match (0=all)"); 190module_param(port, int, 0); 191 192MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); 193module_param(bufsize, int, 0); 194 195MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>"); 196MODULE_DESCRIPTION("DCCP snooper"); 197MODULE_LICENSE("GPL"); 198