Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 1 | /* |
| 2 | * tcpprobe - Observe the TCP 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 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 9 | * the Free Software Foundation; either version 2 of the License. |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 19 | */ |
| 20 | |
Joe Perches | afd46503 | 2012-03-12 07:03:32 +0000 | [diff] [blame] | 21 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 22 | |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 23 | #include <linux/kernel.h> |
| 24 | #include <linux/kprobes.h> |
| 25 | #include <linux/socket.h> |
| 26 | #include <linux/tcp.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 27 | #include <linux/slab.h> |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 28 | #include <linux/proc_fs.h> |
| 29 | #include <linux/module.h> |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 30 | #include <linux/ktime.h> |
| 31 | #include <linux/time.h> |
Eric W. Biederman | 457c4cb | 2007-09-12 12:01:34 +0200 | [diff] [blame] | 32 | #include <net/net_namespace.h> |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 33 | |
| 34 | #include <net/tcp.h> |
| 35 | |
Stephen Hemminger | 65ebe634 | 2007-01-23 11:38:57 -0800 | [diff] [blame] | 36 | MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>"); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 37 | MODULE_DESCRIPTION("TCP cwnd snooper"); |
| 38 | MODULE_LICENSE("GPL"); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 39 | MODULE_VERSION("1.1"); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 40 | |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 41 | static int port __read_mostly = 0; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 42 | MODULE_PARM_DESC(port, "Port to match (0=all)"); |
| 43 | module_param(port, int, 0); |
| 44 | |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 45 | static unsigned int bufsize __read_mostly = 4096; |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 46 | MODULE_PARM_DESC(bufsize, "Log buffer size in packets (4096)"); |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 47 | module_param(bufsize, uint, 0); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 48 | |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 49 | static int full __read_mostly; |
| 50 | MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)"); |
| 51 | module_param(full, int, 0); |
| 52 | |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 53 | static const char procname[] = "tcpprobe"; |
| 54 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 55 | struct tcp_log { |
| 56 | ktime_t tstamp; |
| 57 | __be32 saddr, daddr; |
| 58 | __be16 sport, dport; |
| 59 | u16 length; |
| 60 | u32 snd_nxt; |
| 61 | u32 snd_una; |
| 62 | u32 snd_wnd; |
| 63 | u32 snd_cwnd; |
| 64 | u32 ssthresh; |
| 65 | u32 srtt; |
| 66 | }; |
| 67 | |
| 68 | static struct { |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 69 | spinlock_t lock; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 70 | wait_queue_head_t wait; |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 71 | ktime_t start; |
| 72 | u32 lastcwnd; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 73 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 74 | unsigned long head, tail; |
| 75 | struct tcp_log *log; |
| 76 | } tcp_probe; |
David S. Miller | 14a49e1 | 2007-06-05 00:19:24 -0700 | [diff] [blame] | 77 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 78 | |
| 79 | static inline int tcp_probe_used(void) |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 80 | { |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 81 | return (tcp_probe.head - tcp_probe.tail) & (bufsize - 1); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 82 | } |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 83 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 84 | static inline int tcp_probe_avail(void) |
| 85 | { |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 86 | return bufsize - tcp_probe_used() - 1; |
David S. Miller | 14a49e1 | 2007-06-05 00:19:24 -0700 | [diff] [blame] | 87 | } |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 88 | |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 89 | /* |
| 90 | * Hook inserted to be called before each receive packet. |
| 91 | * Note: arguments must match tcp_rcv_established()! |
| 92 | */ |
| 93 | static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb, |
| 94 | struct tcphdr *th, unsigned len) |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 95 | { |
| 96 | const struct tcp_sock *tp = tcp_sk(sk); |
| 97 | const struct inet_sock *inet = inet_sk(sk); |
| 98 | |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 99 | /* Only update if port matches */ |
Eric Dumazet | c720c7e | 2009-10-15 06:30:45 +0000 | [diff] [blame] | 100 | if ((port == 0 || ntohs(inet->inet_dport) == port || |
Joe Perches | 9d4fb27 | 2009-11-23 10:41:23 -0800 | [diff] [blame] | 101 | ntohs(inet->inet_sport) == port) && |
| 102 | (full || tp->snd_cwnd != tcp_probe.lastcwnd)) { |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 103 | |
| 104 | spin_lock(&tcp_probe.lock); |
| 105 | /* If log fills, just silently drop */ |
| 106 | if (tcp_probe_avail() > 1) { |
| 107 | struct tcp_log *p = tcp_probe.log + tcp_probe.head; |
| 108 | |
| 109 | p->tstamp = ktime_get(); |
Eric Dumazet | c720c7e | 2009-10-15 06:30:45 +0000 | [diff] [blame] | 110 | p->saddr = inet->inet_saddr; |
| 111 | p->sport = inet->inet_sport; |
| 112 | p->daddr = inet->inet_daddr; |
| 113 | p->dport = inet->inet_dport; |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 114 | p->length = skb->len; |
| 115 | p->snd_nxt = tp->snd_nxt; |
| 116 | p->snd_una = tp->snd_una; |
| 117 | p->snd_cwnd = tp->snd_cwnd; |
| 118 | p->snd_wnd = tp->snd_wnd; |
Stephen Hemminger | b3b0b68 | 2007-07-14 18:57:19 -0700 | [diff] [blame] | 119 | p->ssthresh = tcp_current_ssthresh(sk); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 120 | p->srtt = tp->srtt >> 3; |
| 121 | |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 122 | tcp_probe.head = (tcp_probe.head + 1) & (bufsize - 1); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 123 | } |
| 124 | tcp_probe.lastcwnd = tp->snd_cwnd; |
| 125 | spin_unlock(&tcp_probe.lock); |
| 126 | |
| 127 | wake_up(&tcp_probe.wait); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 128 | } |
| 129 | |
| 130 | jprobe_return(); |
| 131 | return 0; |
| 132 | } |
| 133 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 134 | static struct jprobe tcp_jprobe = { |
Ananth N Mavinakayanahalli | 3a872d8 | 2006-10-02 02:17:30 -0700 | [diff] [blame] | 135 | .kp = { |
Stephen Hemminger | 85795d6 | 2007-03-24 21:35:33 -0700 | [diff] [blame] | 136 | .symbol_name = "tcp_rcv_established", |
Ananth N Mavinakayanahalli | 3a872d8 | 2006-10-02 02:17:30 -0700 | [diff] [blame] | 137 | }, |
Michael Ellerman | 9e367d8 | 2007-07-19 01:48:10 -0700 | [diff] [blame] | 138 | .entry = jtcp_rcv_established, |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 139 | }; |
| 140 | |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 141 | static int tcpprobe_open(struct inode * inode, struct file * file) |
| 142 | { |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 143 | /* Reset (empty) log */ |
| 144 | spin_lock_bh(&tcp_probe.lock); |
| 145 | tcp_probe.head = tcp_probe.tail = 0; |
| 146 | tcp_probe.start = ktime_get(); |
| 147 | spin_unlock_bh(&tcp_probe.lock); |
| 148 | |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 149 | return 0; |
| 150 | } |
| 151 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 152 | static int tcpprobe_sprint(char *tbuf, int n) |
| 153 | { |
| 154 | const struct tcp_log *p |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 155 | = tcp_probe.log + tcp_probe.tail; |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 156 | struct timespec tv |
| 157 | = ktime_to_timespec(ktime_sub(p->tstamp, tcp_probe.start)); |
| 158 | |
Vasiliy Kulikov | dda0b38 | 2010-11-14 07:06:08 +0000 | [diff] [blame] | 159 | return scnprintf(tbuf, n, |
Harvey Harrison | 673d57e | 2008-10-31 00:53:57 -0700 | [diff] [blame] | 160 | "%lu.%09lu %pI4:%u %pI4:%u %d %#x %#x %u %u %u %u\n", |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 161 | (unsigned long) tv.tv_sec, |
| 162 | (unsigned long) tv.tv_nsec, |
Harvey Harrison | 673d57e | 2008-10-31 00:53:57 -0700 | [diff] [blame] | 163 | &p->saddr, ntohs(p->sport), |
| 164 | &p->daddr, ntohs(p->dport), |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 165 | p->length, p->snd_nxt, p->snd_una, |
| 166 | p->snd_cwnd, p->ssthresh, p->snd_wnd, p->srtt); |
| 167 | } |
| 168 | |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 169 | static ssize_t tcpprobe_read(struct file *file, char __user *buf, |
| 170 | size_t len, loff_t *ppos) |
| 171 | { |
Roel Kluin | a2025b8 | 2009-03-13 16:05:14 -0700 | [diff] [blame] | 172 | int error = 0; |
| 173 | size_t cnt = 0; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 174 | |
Roel Kluin | a2025b8 | 2009-03-13 16:05:14 -0700 | [diff] [blame] | 175 | if (!buf) |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 176 | return -EINVAL; |
| 177 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 178 | while (cnt < len) { |
Vasiliy Kulikov | dda0b38 | 2010-11-14 07:06:08 +0000 | [diff] [blame] | 179 | char tbuf[164]; |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 180 | int width; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 181 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 182 | /* Wait for data in buffer */ |
| 183 | error = wait_event_interruptible(tcp_probe.wait, |
| 184 | tcp_probe_used() > 0); |
| 185 | if (error) |
| 186 | break; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 187 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 188 | spin_lock_bh(&tcp_probe.lock); |
| 189 | if (tcp_probe.head == tcp_probe.tail) { |
| 190 | /* multiple readers race? */ |
| 191 | spin_unlock_bh(&tcp_probe.lock); |
| 192 | continue; |
| 193 | } |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 194 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 195 | width = tcpprobe_sprint(tbuf, sizeof(tbuf)); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 196 | |
Tom Quetchenbach | 8d390ef | 2008-04-24 21:11:58 -0700 | [diff] [blame] | 197 | if (cnt + width < len) |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 198 | tcp_probe.tail = (tcp_probe.tail + 1) & (bufsize - 1); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 199 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 200 | spin_unlock_bh(&tcp_probe.lock); |
| 201 | |
| 202 | /* if record greater than space available |
| 203 | return partial buffer (so far) */ |
Tom Quetchenbach | 8d390ef | 2008-04-24 21:11:58 -0700 | [diff] [blame] | 204 | if (cnt + width >= len) |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 205 | break; |
| 206 | |
Tom Quetchenbach | 8d390ef | 2008-04-24 21:11:58 -0700 | [diff] [blame] | 207 | if (copy_to_user(buf + cnt, tbuf, width)) |
| 208 | return -EFAULT; |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 209 | cnt += width; |
| 210 | } |
| 211 | |
| 212 | return cnt == 0 ? error : cnt; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 213 | } |
| 214 | |
Arjan van de Ven | 9a32144 | 2007-02-12 00:55:35 -0800 | [diff] [blame] | 215 | static const struct file_operations tcpprobe_fops = { |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 216 | .owner = THIS_MODULE, |
| 217 | .open = tcpprobe_open, |
| 218 | .read = tcpprobe_read, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 219 | .llseek = noop_llseek, |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 220 | }; |
| 221 | |
| 222 | static __init int tcpprobe_init(void) |
| 223 | { |
| 224 | int ret = -ENOMEM; |
| 225 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 226 | init_waitqueue_head(&tcp_probe.wait); |
| 227 | spin_lock_init(&tcp_probe.lock); |
| 228 | |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 229 | if (bufsize == 0) |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 230 | return -EINVAL; |
| 231 | |
Stephen Hemminger | f81074f | 2010-01-25 15:47:50 -0800 | [diff] [blame] | 232 | bufsize = roundup_pow_of_two(bufsize); |
Milton Miller | 3d8ea1f | 2008-07-10 16:51:32 -0700 | [diff] [blame] | 233 | tcp_probe.log = kcalloc(bufsize, sizeof(struct tcp_log), GFP_KERNEL); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 234 | if (!tcp_probe.log) |
| 235 | goto err0; |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 236 | |
Eric W. Biederman | 457c4cb | 2007-09-12 12:01:34 +0200 | [diff] [blame] | 237 | if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &tcpprobe_fops)) |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 238 | goto err0; |
| 239 | |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 240 | ret = register_jprobe(&tcp_jprobe); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 241 | if (ret) |
| 242 | goto err1; |
| 243 | |
Joe Perches | afd46503 | 2012-03-12 07:03:32 +0000 | [diff] [blame] | 244 | pr_info("probe registered (port=%d) bufsize=%u\n", port, bufsize); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 245 | return 0; |
| 246 | err1: |
Eric W. Biederman | 457c4cb | 2007-09-12 12:01:34 +0200 | [diff] [blame] | 247 | proc_net_remove(&init_net, procname); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 248 | err0: |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 249 | kfree(tcp_probe.log); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 250 | return ret; |
| 251 | } |
| 252 | module_init(tcpprobe_init); |
| 253 | |
| 254 | static __exit void tcpprobe_exit(void) |
| 255 | { |
Eric W. Biederman | 457c4cb | 2007-09-12 12:01:34 +0200 | [diff] [blame] | 256 | proc_net_remove(&init_net, procname); |
Stephen Hemminger | 662ad4f | 2007-07-11 19:43:52 -0700 | [diff] [blame] | 257 | unregister_jprobe(&tcp_jprobe); |
| 258 | kfree(tcp_probe.log); |
Stephen Hemminger | a42e9d6 | 2006-06-05 17:30:32 -0700 | [diff] [blame] | 259 | } |
| 260 | module_exit(tcpprobe_exit); |