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 34#include "dccp.h" 35#include "ccid.h" 36#include "ccids/ccid3.h" 37 38static int port; 39 40static int bufsize = 64 * 1024; 41 42static const char procname[] = "dccpprobe"; 43 44struct { 45 struct kfifo *fifo; 46 spinlock_t lock; 47 wait_queue_head_t wait; 48 struct timeval tstart; 49} dccpw; 50 51static void printl(const char *fmt, ...) 52{ 53 va_list args; 54 int len; 55 struct timeval now; 56 char tbuf[256]; 57 58 va_start(args, fmt); 59 do_gettimeofday(&now); 60 61 now.tv_sec -= dccpw.tstart.tv_sec; 62 now.tv_usec -= dccpw.tstart.tv_usec; 63 if (now.tv_usec < 0) { 64 --now.tv_sec; 65 now.tv_usec += 1000000; 66 } 67 68 len = sprintf(tbuf, "%lu.%06lu ", 69 (unsigned long) now.tv_sec, 70 (unsigned long) now.tv_usec); 71 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args); 72 va_end(args); 73 74 kfifo_put(dccpw.fifo, tbuf, len); 75 wake_up(&dccpw.wait); 76} 77 78static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk, 79 struct msghdr *msg, size_t size) 80{ 81 const struct dccp_minisock *dmsk = dccp_msk(sk); 82 const struct inet_sock *inet = inet_sk(sk); 83 const struct ccid3_hc_tx_sock *hctx; 84 85 if (dmsk->dccpms_tx_ccid == DCCPC_CCID3) 86 hctx = ccid3_hc_tx_sk(sk); 87 else 88 hctx = NULL; 89 90 if (port == 0 || ntohs(inet->dport) == port || 91 ntohs(inet->sport) == port) { 92 if (hctx) 93 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u " 94 "%llu %llu %d\n", 95 NIPQUAD(inet->saddr), ntohs(inet->sport), 96 NIPQUAD(inet->daddr), ntohs(inet->dport), size, 97 hctx->ccid3hctx_s, hctx->ccid3hctx_rtt, 98 hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc, 99 hctx->ccid3hctx_x_recv >> 6, 100 hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi); 101 else 102 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n", 103 NIPQUAD(inet->saddr), ntohs(inet->sport), 104 NIPQUAD(inet->daddr), ntohs(inet->dport), size); 105 } 106 107 jprobe_return(); 108 return 0; 109} 110 111static struct jprobe dccp_send_probe = { 112 .kp = { 113 .symbol_name = "dccp_sendmsg", 114 }, 115 .entry = JPROBE_ENTRY(jdccp_sendmsg), 116}; 117 118static int dccpprobe_open(struct inode *inode, struct file *file) 119{ 120 kfifo_reset(dccpw.fifo); 121 do_gettimeofday(&dccpw.tstart); 122 return 0; 123} 124 125static ssize_t dccpprobe_read(struct file *file, char __user *buf, 126 size_t len, loff_t *ppos) 127{ 128 int error = 0, cnt = 0; 129 unsigned char *tbuf; 130 131 if (!buf) 132 return -EINVAL; 133 134 if (len == 0) 135 return 0; 136 137 tbuf = vmalloc(len); 138 if (!tbuf) 139 return -ENOMEM; 140 141 error = wait_event_interruptible(dccpw.wait, 142 __kfifo_len(dccpw.fifo) != 0); 143 if (error) 144 goto out_free; 145 146 cnt = kfifo_get(dccpw.fifo, tbuf, len); 147 error = copy_to_user(buf, tbuf, cnt); 148 149out_free: 150 vfree(tbuf); 151 152 return error ? error : cnt; 153} 154 155static const struct file_operations dccpprobe_fops = { 156 .owner = THIS_MODULE, 157 .open = dccpprobe_open, 158 .read = dccpprobe_read, 159}; 160 161static __init int dccpprobe_init(void) 162{ 163 int ret = -ENOMEM; 164 165 init_waitqueue_head(&dccpw.wait); 166 spin_lock_init(&dccpw.lock); 167 dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock); 168 if (IS_ERR(dccpw.fifo)) 169 return PTR_ERR(dccpw.fifo); 170 171 if (!proc_net_fops_create(procname, S_IRUSR, &dccpprobe_fops)) 172 goto err0; 173 174 ret = register_jprobe(&dccp_send_probe); 175 if (ret) 176 goto err1; 177 178 pr_info("DCCP watch registered (port=%d)\n", port); 179 return 0; 180err1: 181 proc_net_remove(procname); 182err0: 183 kfifo_free(dccpw.fifo); 184 return ret; 185} 186module_init(dccpprobe_init); 187 188static __exit void dccpprobe_exit(void) 189{ 190 kfifo_free(dccpw.fifo); 191 proc_net_remove(procname); 192 unregister_jprobe(&dccp_send_probe); 193 194} 195module_exit(dccpprobe_exit); 196 197MODULE_PARM_DESC(port, "Port to match (0=all)"); 198module_param(port, int, 0); 199 200MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)"); 201module_param(bufsize, int, 0); 202 203MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>"); 204MODULE_DESCRIPTION("DCCP snooper"); 205MODULE_LICENSE("GPL"); 206