Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * NET3: Implementation of the ICMP protocol layer. |
| 3 | * |
| 4 | * Alan Cox, <alan@redhat.com> |
| 5 | * |
| 6 | * Version: $Id: icmp.c,v 1.85 2002/02/01 22:01:03 davem Exp $ |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License |
| 10 | * as published by the Free Software Foundation; either version |
| 11 | * 2 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * Some of the function names and the icmp unreach table for this |
| 14 | * module were derived from [icmp.c 1.0.11 06/02/93] by |
| 15 | * Ross Biro, Fred N. van Kempen, Mark Evans, Alan Cox, Gerhard Koerting. |
| 16 | * Other than that this module is a complete rewrite. |
| 17 | * |
| 18 | * Fixes: |
| 19 | * Clemens Fruhwirth : introduce global icmp rate limiting |
| 20 | * with icmp type masking ability instead |
| 21 | * of broken per type icmp timeouts. |
| 22 | * Mike Shaver : RFC1122 checks. |
| 23 | * Alan Cox : Multicast ping reply as self. |
| 24 | * Alan Cox : Fix atomicity lockup in ip_build_xmit |
| 25 | * call. |
| 26 | * Alan Cox : Added 216,128 byte paths to the MTU |
| 27 | * code. |
| 28 | * Martin Mares : RFC1812 checks. |
| 29 | * Martin Mares : Can be configured to follow redirects |
| 30 | * if acting as a router _without_ a |
| 31 | * routing protocol (RFC 1812). |
| 32 | * Martin Mares : Echo requests may be configured to |
| 33 | * be ignored (RFC 1812). |
| 34 | * Martin Mares : Limitation of ICMP error message |
| 35 | * transmit rate (RFC 1812). |
| 36 | * Martin Mares : TOS and Precedence set correctly |
| 37 | * (RFC 1812). |
| 38 | * Martin Mares : Now copying as much data from the |
| 39 | * original packet as we can without |
| 40 | * exceeding 576 bytes (RFC 1812). |
| 41 | * Willy Konynenberg : Transparent proxying support. |
| 42 | * Keith Owens : RFC1191 correction for 4.2BSD based |
| 43 | * path MTU bug. |
| 44 | * Thomas Quinot : ICMP Dest Unreach codes up to 15 are |
| 45 | * valid (RFC 1812). |
| 46 | * Andi Kleen : Check all packet lengths properly |
| 47 | * and moved all kfree_skb() up to |
| 48 | * icmp_rcv. |
| 49 | * Andi Kleen : Move the rate limit bookkeeping |
| 50 | * into the dest entry and use a token |
| 51 | * bucket filter (thanks to ANK). Make |
| 52 | * the rates sysctl configurable. |
| 53 | * Yu Tianli : Fixed two ugly bugs in icmp_send |
| 54 | * - IP option length was accounted wrongly |
| 55 | * - ICMP header length was not accounted |
| 56 | * at all. |
| 57 | * Tristan Greaves : Added sysctl option to ignore bogus |
| 58 | * broadcast responses from broken routers. |
| 59 | * |
| 60 | * To Fix: |
| 61 | * |
| 62 | * - Should use skb_pull() instead of all the manual checking. |
| 63 | * This would also greatly simply some upper layer error handlers. --AK |
| 64 | * |
| 65 | */ |
| 66 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | #include <linux/module.h> |
| 68 | #include <linux/types.h> |
| 69 | #include <linux/jiffies.h> |
| 70 | #include <linux/kernel.h> |
| 71 | #include <linux/fcntl.h> |
| 72 | #include <linux/socket.h> |
| 73 | #include <linux/in.h> |
| 74 | #include <linux/inet.h> |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 75 | #include <linux/inetdevice.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | #include <linux/netdevice.h> |
| 77 | #include <linux/string.h> |
| 78 | #include <linux/netfilter_ipv4.h> |
| 79 | #include <net/snmp.h> |
| 80 | #include <net/ip.h> |
| 81 | #include <net/route.h> |
| 82 | #include <net/protocol.h> |
| 83 | #include <net/icmp.h> |
| 84 | #include <net/tcp.h> |
| 85 | #include <net/udp.h> |
| 86 | #include <net/raw.h> |
| 87 | #include <linux/skbuff.h> |
| 88 | #include <net/sock.h> |
| 89 | #include <linux/errno.h> |
| 90 | #include <linux/timer.h> |
| 91 | #include <linux/init.h> |
| 92 | #include <asm/system.h> |
| 93 | #include <asm/uaccess.h> |
| 94 | #include <net/checksum.h> |
| 95 | |
| 96 | /* |
| 97 | * Build xmit assembly blocks |
| 98 | */ |
| 99 | |
| 100 | struct icmp_bxm { |
| 101 | struct sk_buff *skb; |
| 102 | int offset; |
| 103 | int data_len; |
| 104 | |
| 105 | struct { |
| 106 | struct icmphdr icmph; |
Al Viro | b03d73e | 2006-09-27 18:38:30 -0700 | [diff] [blame] | 107 | __be32 times[3]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | } data; |
| 109 | int head_len; |
| 110 | struct ip_options replyopts; |
| 111 | unsigned char optbuf[40]; |
| 112 | }; |
| 113 | |
| 114 | /* |
| 115 | * Statistics |
| 116 | */ |
Eric Dumazet | ba89966 | 2005-08-26 12:05:31 -0700 | [diff] [blame] | 117 | DEFINE_SNMP_STAT(struct icmp_mib, icmp_statistics) __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | |
| 119 | /* An array of errno for error messages from dest unreach. */ |
| 120 | /* RFC 1122: 3.2.2.1 States that NET_UNREACH, HOST_UNREACH and SR_FAILED MUST be considered 'transient errs'. */ |
| 121 | |
| 122 | struct icmp_err icmp_err_convert[] = { |
| 123 | { |
| 124 | .errno = ENETUNREACH, /* ICMP_NET_UNREACH */ |
| 125 | .fatal = 0, |
| 126 | }, |
| 127 | { |
| 128 | .errno = EHOSTUNREACH, /* ICMP_HOST_UNREACH */ |
| 129 | .fatal = 0, |
| 130 | }, |
| 131 | { |
| 132 | .errno = ENOPROTOOPT /* ICMP_PROT_UNREACH */, |
| 133 | .fatal = 1, |
| 134 | }, |
| 135 | { |
| 136 | .errno = ECONNREFUSED, /* ICMP_PORT_UNREACH */ |
| 137 | .fatal = 1, |
| 138 | }, |
| 139 | { |
| 140 | .errno = EMSGSIZE, /* ICMP_FRAG_NEEDED */ |
| 141 | .fatal = 0, |
| 142 | }, |
| 143 | { |
| 144 | .errno = EOPNOTSUPP, /* ICMP_SR_FAILED */ |
| 145 | .fatal = 0, |
| 146 | }, |
| 147 | { |
| 148 | .errno = ENETUNREACH, /* ICMP_NET_UNKNOWN */ |
| 149 | .fatal = 1, |
| 150 | }, |
| 151 | { |
| 152 | .errno = EHOSTDOWN, /* ICMP_HOST_UNKNOWN */ |
| 153 | .fatal = 1, |
| 154 | }, |
| 155 | { |
| 156 | .errno = ENONET, /* ICMP_HOST_ISOLATED */ |
| 157 | .fatal = 1, |
| 158 | }, |
| 159 | { |
| 160 | .errno = ENETUNREACH, /* ICMP_NET_ANO */ |
| 161 | .fatal = 1, |
| 162 | }, |
| 163 | { |
| 164 | .errno = EHOSTUNREACH, /* ICMP_HOST_ANO */ |
| 165 | .fatal = 1, |
| 166 | }, |
| 167 | { |
| 168 | .errno = ENETUNREACH, /* ICMP_NET_UNR_TOS */ |
| 169 | .fatal = 0, |
| 170 | }, |
| 171 | { |
| 172 | .errno = EHOSTUNREACH, /* ICMP_HOST_UNR_TOS */ |
| 173 | .fatal = 0, |
| 174 | }, |
| 175 | { |
| 176 | .errno = EHOSTUNREACH, /* ICMP_PKT_FILTERED */ |
| 177 | .fatal = 1, |
| 178 | }, |
| 179 | { |
| 180 | .errno = EHOSTUNREACH, /* ICMP_PREC_VIOLATION */ |
| 181 | .fatal = 1, |
| 182 | }, |
| 183 | { |
| 184 | .errno = EHOSTUNREACH, /* ICMP_PREC_CUTOFF */ |
| 185 | .fatal = 1, |
| 186 | }, |
| 187 | }; |
| 188 | |
| 189 | /* Control parameters for ECHO replies. */ |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 190 | int sysctl_icmp_echo_ignore_all __read_mostly; |
| 191 | int sysctl_icmp_echo_ignore_broadcasts __read_mostly = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | |
| 193 | /* Control parameter - ignore bogus broadcast responses? */ |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 194 | int sysctl_icmp_ignore_bogus_error_responses __read_mostly = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | |
| 196 | /* |
| 197 | * Configurable global rate limit. |
| 198 | * |
| 199 | * ratelimit defines tokens/packet consumed for dst->rate_token bucket |
| 200 | * ratemask defines which icmp types are ratelimited by setting |
| 201 | * it's bit position. |
| 202 | * |
| 203 | * default: |
| 204 | * dest unreachable (3), source quench (4), |
| 205 | * time exceeded (11), parameter problem (12) |
| 206 | */ |
| 207 | |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 208 | int sysctl_icmp_ratelimit __read_mostly = 1 * HZ; |
| 209 | int sysctl_icmp_ratemask __read_mostly = 0x1818; |
| 210 | int sysctl_icmp_errors_use_inbound_ifaddr __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | |
| 212 | /* |
| 213 | * ICMP control array. This specifies what to do with each ICMP. |
| 214 | */ |
| 215 | |
| 216 | struct icmp_control { |
| 217 | int output_entry; /* Field for increment on output */ |
| 218 | int input_entry; /* Field for increment on input */ |
| 219 | void (*handler)(struct sk_buff *skb); |
| 220 | short error; /* This ICMP is classed as an error message */ |
| 221 | }; |
| 222 | |
Arjan van de Ven | 9b5b5cf | 2005-11-29 16:21:38 -0800 | [diff] [blame] | 223 | static const struct icmp_control icmp_pointers[NR_ICMP_TYPES+1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | |
| 225 | /* |
| 226 | * The ICMP socket(s). This is the most convenient way to flow control |
| 227 | * our ICMP output as well as maintain a clean interface throughout |
| 228 | * all layers. All Socketless IP sends will soon be gone. |
| 229 | * |
| 230 | * On SMP we have one ICMP socket per-cpu. |
| 231 | */ |
| 232 | static DEFINE_PER_CPU(struct socket *, __icmp_socket) = NULL; |
| 233 | #define icmp_socket __get_cpu_var(__icmp_socket) |
| 234 | |
| 235 | static __inline__ int icmp_xmit_lock(void) |
| 236 | { |
| 237 | local_bh_disable(); |
| 238 | |
| 239 | if (unlikely(!spin_trylock(&icmp_socket->sk->sk_lock.slock))) { |
| 240 | /* This can happen if the output path signals a |
| 241 | * dst_link_failure() for an outgoing ICMP packet. |
| 242 | */ |
| 243 | local_bh_enable(); |
| 244 | return 1; |
| 245 | } |
| 246 | return 0; |
| 247 | } |
| 248 | |
| 249 | static void icmp_xmit_unlock(void) |
| 250 | { |
| 251 | spin_unlock_bh(&icmp_socket->sk->sk_lock.slock); |
| 252 | } |
| 253 | |
| 254 | /* |
| 255 | * Send an ICMP frame. |
| 256 | */ |
| 257 | |
| 258 | /* |
| 259 | * Check transmit rate limitation for given message. |
| 260 | * The rate information is held in the destination cache now. |
| 261 | * This function is generic and could be used for other purposes |
| 262 | * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov. |
| 263 | * |
| 264 | * Note that the same dst_entry fields are modified by functions in |
| 265 | * route.c too, but these work for packet destinations while xrlim_allow |
| 266 | * works for icmp destinations. This means the rate limiting information |
| 267 | * for one "ip object" is shared - and these ICMPs are twice limited: |
| 268 | * by source and by destination. |
| 269 | * |
| 270 | * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate |
| 271 | * SHOULD allow setting of rate limits |
| 272 | * |
| 273 | * Shared between ICMPv4 and ICMPv6. |
| 274 | */ |
| 275 | #define XRLIM_BURST_FACTOR 6 |
| 276 | int xrlim_allow(struct dst_entry *dst, int timeout) |
| 277 | { |
| 278 | unsigned long now; |
| 279 | int rc = 0; |
| 280 | |
| 281 | now = jiffies; |
| 282 | dst->rate_tokens += now - dst->rate_last; |
| 283 | dst->rate_last = now; |
| 284 | if (dst->rate_tokens > XRLIM_BURST_FACTOR * timeout) |
| 285 | dst->rate_tokens = XRLIM_BURST_FACTOR * timeout; |
| 286 | if (dst->rate_tokens >= timeout) { |
| 287 | dst->rate_tokens -= timeout; |
| 288 | rc = 1; |
| 289 | } |
| 290 | return rc; |
| 291 | } |
| 292 | |
| 293 | static inline int icmpv4_xrlim_allow(struct rtable *rt, int type, int code) |
| 294 | { |
| 295 | struct dst_entry *dst = &rt->u.dst; |
| 296 | int rc = 1; |
| 297 | |
| 298 | if (type > NR_ICMP_TYPES) |
| 299 | goto out; |
| 300 | |
| 301 | /* Don't limit PMTU discovery. */ |
| 302 | if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) |
| 303 | goto out; |
| 304 | |
| 305 | /* No rate limit on loopback */ |
| 306 | if (dst->dev && (dst->dev->flags&IFF_LOOPBACK)) |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 307 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | |
| 309 | /* Limit if icmp type is enabled in ratemask. */ |
| 310 | if ((1 << type) & sysctl_icmp_ratemask) |
| 311 | rc = xrlim_allow(dst, sysctl_icmp_ratelimit); |
| 312 | out: |
| 313 | return rc; |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | * Maintain the counters used in the SNMP statistics for outgoing ICMP |
| 318 | */ |
| 319 | static void icmp_out_count(int type) |
| 320 | { |
| 321 | if (type <= NR_ICMP_TYPES) { |
| 322 | ICMP_INC_STATS(icmp_pointers[type].output_entry); |
| 323 | ICMP_INC_STATS(ICMP_MIB_OUTMSGS); |
| 324 | } |
| 325 | } |
| 326 | |
| 327 | /* |
| 328 | * Checksum each fragment, and on the first include the headers and final |
| 329 | * checksum. |
| 330 | */ |
| 331 | static int icmp_glue_bits(void *from, char *to, int offset, int len, int odd, |
| 332 | struct sk_buff *skb) |
| 333 | { |
| 334 | struct icmp_bxm *icmp_param = (struct icmp_bxm *)from; |
Al Viro | 5f92a73 | 2006-11-14 21:36:54 -0800 | [diff] [blame] | 335 | __wsum csum; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | |
| 337 | csum = skb_copy_and_csum_bits(icmp_param->skb, |
| 338 | icmp_param->offset + offset, |
| 339 | to, len, 0); |
| 340 | |
| 341 | skb->csum = csum_block_add(skb->csum, csum, odd); |
| 342 | if (icmp_pointers[icmp_param->data.icmph.type].error) |
| 343 | nf_ct_attach(skb, icmp_param->skb); |
| 344 | return 0; |
| 345 | } |
| 346 | |
| 347 | static void icmp_push_reply(struct icmp_bxm *icmp_param, |
| 348 | struct ipcm_cookie *ipc, struct rtable *rt) |
| 349 | { |
| 350 | struct sk_buff *skb; |
| 351 | |
Patrick McHardy | cb94c62 | 2005-08-18 14:05:44 -0700 | [diff] [blame] | 352 | if (ip_append_data(icmp_socket->sk, icmp_glue_bits, icmp_param, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 353 | icmp_param->data_len+icmp_param->head_len, |
| 354 | icmp_param->head_len, |
| 355 | ipc, rt, MSG_DONTWAIT) < 0) |
Patrick McHardy | cb94c62 | 2005-08-18 14:05:44 -0700 | [diff] [blame] | 356 | ip_flush_pending_frames(icmp_socket->sk); |
| 357 | else if ((skb = skb_peek(&icmp_socket->sk->sk_write_queue)) != NULL) { |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 358 | struct icmphdr *icmph = icmp_hdr(skb); |
Al Viro | d3bc23e | 2006-11-14 21:24:49 -0800 | [diff] [blame] | 359 | __wsum csum = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | struct sk_buff *skb1; |
| 361 | |
| 362 | skb_queue_walk(&icmp_socket->sk->sk_write_queue, skb1) { |
| 363 | csum = csum_add(csum, skb1->csum); |
| 364 | } |
| 365 | csum = csum_partial_copy_nocheck((void *)&icmp_param->data, |
| 366 | (char *)icmph, |
| 367 | icmp_param->head_len, csum); |
| 368 | icmph->checksum = csum_fold(csum); |
| 369 | skb->ip_summed = CHECKSUM_NONE; |
| 370 | ip_push_pending_frames(icmp_socket->sk); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | /* |
| 375 | * Driving logic for building and sending ICMP messages. |
| 376 | */ |
| 377 | |
| 378 | static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb) |
| 379 | { |
| 380 | struct sock *sk = icmp_socket->sk; |
| 381 | struct inet_sock *inet = inet_sk(sk); |
| 382 | struct ipcm_cookie ipc; |
| 383 | struct rtable *rt = (struct rtable *)skb->dst; |
Al Viro | 3ca3c68 | 2006-09-27 18:28:07 -0700 | [diff] [blame] | 384 | __be32 daddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 385 | |
| 386 | if (ip_options_echo(&icmp_param->replyopts, skb)) |
Horms | f00c401 | 2006-02-02 17:03:18 -0800 | [diff] [blame] | 387 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | |
| 389 | if (icmp_xmit_lock()) |
| 390 | return; |
| 391 | |
| 392 | icmp_param->data.icmph.checksum = 0; |
| 393 | icmp_out_count(icmp_param->data.icmph.type); |
| 394 | |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 395 | inet->tos = ip_hdr(skb)->tos; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | daddr = ipc.addr = rt->rt_src; |
| 397 | ipc.opt = NULL; |
| 398 | if (icmp_param->replyopts.optlen) { |
| 399 | ipc.opt = &icmp_param->replyopts; |
| 400 | if (ipc.opt->srr) |
| 401 | daddr = icmp_param->replyopts.faddr; |
| 402 | } |
| 403 | { |
| 404 | struct flowi fl = { .nl_u = { .ip4_u = |
| 405 | { .daddr = daddr, |
| 406 | .saddr = rt->rt_spec_dst, |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 407 | .tos = RT_TOS(ip_hdr(skb)->tos) } }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | .proto = IPPROTO_ICMP }; |
Venkat Yekkirala | beb8d13 | 2006-08-04 23:12:42 -0700 | [diff] [blame] | 409 | security_skb_classify_flow(skb, &fl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 410 | if (ip_route_output_key(&rt, &fl)) |
| 411 | goto out_unlock; |
| 412 | } |
| 413 | if (icmpv4_xrlim_allow(rt, icmp_param->data.icmph.type, |
| 414 | icmp_param->data.icmph.code)) |
| 415 | icmp_push_reply(icmp_param, &ipc, rt); |
| 416 | ip_rt_put(rt); |
| 417 | out_unlock: |
| 418 | icmp_xmit_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | } |
| 420 | |
| 421 | |
| 422 | /* |
| 423 | * Send an ICMP message in response to a situation |
| 424 | * |
| 425 | * RFC 1122: 3.2.2 MUST send at least the IP header and 8 bytes of header. |
| 426 | * MAY send more (we do). |
| 427 | * MUST NOT change this header information. |
| 428 | * MUST NOT reply to a multicast/broadcast IP address. |
| 429 | * MUST NOT reply to a multicast/broadcast MAC address. |
| 430 | * MUST reply to only the first fragment. |
| 431 | */ |
| 432 | |
Al Viro | e488301 | 2006-09-26 22:17:28 -0700 | [diff] [blame] | 433 | void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | { |
| 435 | struct iphdr *iph; |
| 436 | int room; |
| 437 | struct icmp_bxm icmp_param; |
| 438 | struct rtable *rt = (struct rtable *)skb_in->dst; |
| 439 | struct ipcm_cookie ipc; |
Al Viro | a61ced5 | 2006-09-26 21:27:54 -0700 | [diff] [blame] | 440 | __be32 saddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 441 | u8 tos; |
| 442 | |
| 443 | if (!rt) |
| 444 | goto out; |
| 445 | |
| 446 | /* |
| 447 | * Find the original header. It is expected to be valid, of course. |
| 448 | * Check this, icmp_send is called from the most obscure devices |
| 449 | * sometimes. |
| 450 | */ |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 451 | iph = ip_hdr(skb_in); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | |
| 453 | if ((u8 *)iph < skb_in->head || (u8 *)(iph + 1) > skb_in->tail) |
| 454 | goto out; |
| 455 | |
| 456 | /* |
| 457 | * No replies to physical multicast/broadcast |
| 458 | */ |
| 459 | if (skb_in->pkt_type != PACKET_HOST) |
| 460 | goto out; |
| 461 | |
| 462 | /* |
| 463 | * Now check at the protocol level |
| 464 | */ |
| 465 | if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) |
| 466 | goto out; |
| 467 | |
| 468 | /* |
| 469 | * Only reply to fragment 0. We byte re-order the constant |
| 470 | * mask for efficiency. |
| 471 | */ |
| 472 | if (iph->frag_off & htons(IP_OFFSET)) |
| 473 | goto out; |
| 474 | |
| 475 | /* |
| 476 | * If we send an ICMP error to an ICMP error a mess would result.. |
| 477 | */ |
| 478 | if (icmp_pointers[type].error) { |
| 479 | /* |
| 480 | * We are an error, check if we are replying to an |
| 481 | * ICMP error |
| 482 | */ |
| 483 | if (iph->protocol == IPPROTO_ICMP) { |
| 484 | u8 _inner_type, *itp; |
| 485 | |
| 486 | itp = skb_header_pointer(skb_in, |
Arnaldo Carvalho de Melo | d56f90a | 2007-04-10 20:50:43 -0700 | [diff] [blame] | 487 | skb_network_header(skb_in) + |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | (iph->ihl << 2) + |
| 489 | offsetof(struct icmphdr, |
| 490 | type) - |
| 491 | skb_in->data, |
| 492 | sizeof(_inner_type), |
| 493 | &_inner_type); |
| 494 | if (itp == NULL) |
| 495 | goto out; |
| 496 | |
| 497 | /* |
| 498 | * Assume any unknown ICMP type is an error. This |
| 499 | * isn't specified by the RFC, but think about it.. |
| 500 | */ |
| 501 | if (*itp > NR_ICMP_TYPES || |
| 502 | icmp_pointers[*itp].error) |
| 503 | goto out; |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | if (icmp_xmit_lock()) |
| 508 | return; |
| 509 | |
| 510 | /* |
| 511 | * Construct source address and options. |
| 512 | */ |
| 513 | |
| 514 | saddr = iph->daddr; |
J. Simonetti | 1c2fb7f | 2005-06-13 15:19:03 -0700 | [diff] [blame] | 515 | if (!(rt->rt_flags & RTCF_LOCAL)) { |
| 516 | if (sysctl_icmp_errors_use_inbound_ifaddr) |
| 517 | saddr = inet_select_addr(skb_in->dev, 0, RT_SCOPE_LINK); |
| 518 | else |
| 519 | saddr = 0; |
| 520 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | |
| 522 | tos = icmp_pointers[type].error ? ((iph->tos & IPTOS_TOS_MASK) | |
| 523 | IPTOS_PREC_INTERNETCONTROL) : |
| 524 | iph->tos; |
| 525 | |
| 526 | if (ip_options_echo(&icmp_param.replyopts, skb_in)) |
Herbert Xu | fa60cf7 | 2006-02-04 02:09:34 -0800 | [diff] [blame] | 527 | goto out_unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 528 | |
| 529 | |
| 530 | /* |
| 531 | * Prepare data for ICMP header. |
| 532 | */ |
| 533 | |
| 534 | icmp_param.data.icmph.type = type; |
| 535 | icmp_param.data.icmph.code = code; |
| 536 | icmp_param.data.icmph.un.gateway = info; |
| 537 | icmp_param.data.icmph.checksum = 0; |
| 538 | icmp_param.skb = skb_in; |
Arnaldo Carvalho de Melo | d56f90a | 2007-04-10 20:50:43 -0700 | [diff] [blame] | 539 | icmp_param.offset = skb_network_offset(skb_in); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | icmp_out_count(icmp_param.data.icmph.type); |
| 541 | inet_sk(icmp_socket->sk)->tos = tos; |
| 542 | ipc.addr = iph->saddr; |
| 543 | ipc.opt = &icmp_param.replyopts; |
| 544 | |
| 545 | { |
| 546 | struct flowi fl = { |
| 547 | .nl_u = { |
| 548 | .ip4_u = { |
| 549 | .daddr = icmp_param.replyopts.srr ? |
| 550 | icmp_param.replyopts.faddr : |
| 551 | iph->saddr, |
| 552 | .saddr = saddr, |
| 553 | .tos = RT_TOS(tos) |
| 554 | } |
| 555 | }, |
| 556 | .proto = IPPROTO_ICMP, |
| 557 | .uli_u = { |
| 558 | .icmpt = { |
| 559 | .type = type, |
| 560 | .code = code |
| 561 | } |
| 562 | } |
| 563 | }; |
Venkat Yekkirala | beb8d13 | 2006-08-04 23:12:42 -0700 | [diff] [blame] | 564 | security_skb_classify_flow(skb_in, &fl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 565 | if (ip_route_output_key(&rt, &fl)) |
| 566 | goto out_unlock; |
| 567 | } |
| 568 | |
| 569 | if (!icmpv4_xrlim_allow(rt, type, code)) |
| 570 | goto ende; |
| 571 | |
| 572 | /* RFC says return as much as we can without exceeding 576 bytes. */ |
| 573 | |
| 574 | room = dst_mtu(&rt->u.dst); |
| 575 | if (room > 576) |
| 576 | room = 576; |
| 577 | room -= sizeof(struct iphdr) + icmp_param.replyopts.optlen; |
| 578 | room -= sizeof(struct icmphdr); |
| 579 | |
| 580 | icmp_param.data_len = skb_in->len - icmp_param.offset; |
| 581 | if (icmp_param.data_len > room) |
| 582 | icmp_param.data_len = room; |
| 583 | icmp_param.head_len = sizeof(struct icmphdr); |
| 584 | |
| 585 | icmp_push_reply(&icmp_param, &ipc, rt); |
| 586 | ende: |
| 587 | ip_rt_put(rt); |
| 588 | out_unlock: |
| 589 | icmp_xmit_unlock(); |
| 590 | out:; |
| 591 | } |
| 592 | |
| 593 | |
| 594 | /* |
| 595 | * Handle ICMP_DEST_UNREACH, ICMP_TIME_EXCEED, and ICMP_QUENCH. |
| 596 | */ |
| 597 | |
| 598 | static void icmp_unreach(struct sk_buff *skb) |
| 599 | { |
| 600 | struct iphdr *iph; |
| 601 | struct icmphdr *icmph; |
| 602 | int hash, protocol; |
| 603 | struct net_protocol *ipprot; |
| 604 | struct sock *raw_sk; |
| 605 | u32 info = 0; |
| 606 | |
| 607 | /* |
| 608 | * Incomplete header ? |
| 609 | * Only checks for the IP header, there should be an |
| 610 | * additional check for longer headers in upper levels. |
| 611 | */ |
| 612 | |
| 613 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| 614 | goto out_err; |
| 615 | |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 616 | icmph = icmp_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | iph = (struct iphdr *)skb->data; |
| 618 | |
| 619 | if (iph->ihl < 5) /* Mangled header, drop. */ |
| 620 | goto out_err; |
| 621 | |
| 622 | if (icmph->type == ICMP_DEST_UNREACH) { |
| 623 | switch (icmph->code & 15) { |
| 624 | case ICMP_NET_UNREACH: |
| 625 | case ICMP_HOST_UNREACH: |
| 626 | case ICMP_PROT_UNREACH: |
| 627 | case ICMP_PORT_UNREACH: |
| 628 | break; |
| 629 | case ICMP_FRAG_NEEDED: |
| 630 | if (ipv4_config.no_pmtu_disc) { |
Patrick McHardy | 64ce207 | 2005-08-09 20:50:53 -0700 | [diff] [blame] | 631 | LIMIT_NETDEBUG(KERN_INFO "ICMP: %u.%u.%u.%u: " |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | "fragmentation needed " |
| 633 | "and DF set.\n", |
Patrick McHardy | 64ce207 | 2005-08-09 20:50:53 -0700 | [diff] [blame] | 634 | NIPQUAD(iph->daddr)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | } else { |
| 636 | info = ip_rt_frag_needed(iph, |
| 637 | ntohs(icmph->un.frag.mtu)); |
| 638 | if (!info) |
| 639 | goto out; |
| 640 | } |
| 641 | break; |
| 642 | case ICMP_SR_FAILED: |
Patrick McHardy | 64ce207 | 2005-08-09 20:50:53 -0700 | [diff] [blame] | 643 | LIMIT_NETDEBUG(KERN_INFO "ICMP: %u.%u.%u.%u: Source " |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | "Route Failed.\n", |
Patrick McHardy | 64ce207 | 2005-08-09 20:50:53 -0700 | [diff] [blame] | 645 | NIPQUAD(iph->daddr)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 646 | break; |
| 647 | default: |
| 648 | break; |
| 649 | } |
| 650 | if (icmph->code > NR_ICMP_UNREACH) |
| 651 | goto out; |
| 652 | } else if (icmph->type == ICMP_PARAMETERPROB) |
| 653 | info = ntohl(icmph->un.gateway) >> 24; |
| 654 | |
| 655 | /* |
| 656 | * Throw it at our lower layers |
| 657 | * |
| 658 | * RFC 1122: 3.2.2 MUST extract the protocol ID from the passed |
| 659 | * header. |
| 660 | * RFC 1122: 3.2.2.1 MUST pass ICMP unreach messages to the |
| 661 | * transport layer. |
| 662 | * RFC 1122: 3.2.2.2 MUST pass ICMP time expired messages to |
| 663 | * transport layer. |
| 664 | */ |
| 665 | |
| 666 | /* |
| 667 | * Check the other end isnt violating RFC 1122. Some routers send |
| 668 | * bogus responses to broadcast frames. If you see this message |
| 669 | * first check your netmask matches at both ends, if it does then |
| 670 | * get the other vendor to fix their kit. |
| 671 | */ |
| 672 | |
| 673 | if (!sysctl_icmp_ignore_bogus_error_responses && |
| 674 | inet_addr_type(iph->daddr) == RTN_BROADCAST) { |
| 675 | if (net_ratelimit()) |
| 676 | printk(KERN_WARNING "%u.%u.%u.%u sent an invalid ICMP " |
| 677 | "type %u, code %u " |
| 678 | "error to a broadcast: %u.%u.%u.%u on %s\n", |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 679 | NIPQUAD(ip_hdr(skb)->saddr), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | icmph->type, icmph->code, |
| 681 | NIPQUAD(iph->daddr), |
| 682 | skb->dev->name); |
| 683 | goto out; |
| 684 | } |
| 685 | |
| 686 | /* Checkin full IP header plus 8 bytes of protocol to |
| 687 | * avoid additional coding at protocol handlers. |
| 688 | */ |
| 689 | if (!pskb_may_pull(skb, iph->ihl * 4 + 8)) |
| 690 | goto out; |
| 691 | |
| 692 | iph = (struct iphdr *)skb->data; |
| 693 | protocol = iph->protocol; |
| 694 | |
| 695 | /* |
| 696 | * Deliver ICMP message to raw sockets. Pretty useless feature? |
| 697 | */ |
| 698 | |
| 699 | /* Note: See raw.c and net/raw.h, RAWV4_HTABLE_SIZE==MAX_INET_PROTOS */ |
| 700 | hash = protocol & (MAX_INET_PROTOS - 1); |
| 701 | read_lock(&raw_v4_lock); |
| 702 | if ((raw_sk = sk_head(&raw_v4_htable[hash])) != NULL) { |
| 703 | while ((raw_sk = __raw_v4_lookup(raw_sk, protocol, iph->daddr, |
| 704 | iph->saddr, |
| 705 | skb->dev->ifindex)) != NULL) { |
| 706 | raw_err(raw_sk, skb, info); |
| 707 | raw_sk = sk_next(raw_sk); |
| 708 | iph = (struct iphdr *)skb->data; |
| 709 | } |
| 710 | } |
| 711 | read_unlock(&raw_v4_lock); |
| 712 | |
| 713 | rcu_read_lock(); |
| 714 | ipprot = rcu_dereference(inet_protos[hash]); |
| 715 | if (ipprot && ipprot->err_handler) |
| 716 | ipprot->err_handler(skb, info); |
| 717 | rcu_read_unlock(); |
| 718 | |
| 719 | out: |
| 720 | return; |
| 721 | out_err: |
| 722 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
| 723 | goto out; |
| 724 | } |
| 725 | |
| 726 | |
| 727 | /* |
| 728 | * Handle ICMP_REDIRECT. |
| 729 | */ |
| 730 | |
| 731 | static void icmp_redirect(struct sk_buff *skb) |
| 732 | { |
| 733 | struct iphdr *iph; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 734 | |
| 735 | if (skb->len < sizeof(struct iphdr)) |
| 736 | goto out_err; |
| 737 | |
| 738 | /* |
| 739 | * Get the copied header of the packet that caused the redirect |
| 740 | */ |
| 741 | if (!pskb_may_pull(skb, sizeof(struct iphdr))) |
| 742 | goto out; |
| 743 | |
| 744 | iph = (struct iphdr *)skb->data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 745 | |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 746 | switch (icmp_hdr(skb)->code & 7) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 747 | case ICMP_REDIR_NET: |
| 748 | case ICMP_REDIR_NETTOS: |
| 749 | /* |
| 750 | * As per RFC recommendations now handle it as a host redirect. |
| 751 | */ |
| 752 | case ICMP_REDIR_HOST: |
| 753 | case ICMP_REDIR_HOSTTOS: |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 754 | ip_rt_redirect(ip_hdr(skb)->saddr, iph->daddr, |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 755 | icmp_hdr(skb)->un.gateway, |
Ilia Sotnikov | cef2685 | 2006-03-25 01:38:55 -0800 | [diff] [blame] | 756 | iph->saddr, skb->dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 757 | break; |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 758 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | out: |
| 760 | return; |
| 761 | out_err: |
| 762 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
| 763 | goto out; |
| 764 | } |
| 765 | |
| 766 | /* |
| 767 | * Handle ICMP_ECHO ("ping") requests. |
| 768 | * |
| 769 | * RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo |
| 770 | * requests. |
| 771 | * RFC 1122: 3.2.2.6 Data received in the ICMP_ECHO request MUST be |
| 772 | * included in the reply. |
| 773 | * RFC 1812: 4.3.3.6 SHOULD have a config option for silently ignoring |
| 774 | * echo requests, MUST have default=NOT. |
| 775 | * See also WRT handling of options once they are done and working. |
| 776 | */ |
| 777 | |
| 778 | static void icmp_echo(struct sk_buff *skb) |
| 779 | { |
| 780 | if (!sysctl_icmp_echo_ignore_all) { |
| 781 | struct icmp_bxm icmp_param; |
| 782 | |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 783 | icmp_param.data.icmph = *icmp_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | icmp_param.data.icmph.type = ICMP_ECHOREPLY; |
| 785 | icmp_param.skb = skb; |
| 786 | icmp_param.offset = 0; |
| 787 | icmp_param.data_len = skb->len; |
| 788 | icmp_param.head_len = sizeof(struct icmphdr); |
| 789 | icmp_reply(&icmp_param, skb); |
| 790 | } |
| 791 | } |
| 792 | |
| 793 | /* |
| 794 | * Handle ICMP Timestamp requests. |
| 795 | * RFC 1122: 3.2.2.8 MAY implement ICMP timestamp requests. |
| 796 | * SHOULD be in the kernel for minimum random latency. |
| 797 | * MUST be accurate to a few minutes. |
| 798 | * MUST be updated at least at 15Hz. |
| 799 | */ |
| 800 | static void icmp_timestamp(struct sk_buff *skb) |
| 801 | { |
| 802 | struct timeval tv; |
| 803 | struct icmp_bxm icmp_param; |
| 804 | /* |
| 805 | * Too short. |
| 806 | */ |
| 807 | if (skb->len < 4) |
| 808 | goto out_err; |
| 809 | |
| 810 | /* |
| 811 | * Fill in the current time as ms since midnight UT: |
| 812 | */ |
| 813 | do_gettimeofday(&tv); |
| 814 | icmp_param.data.times[1] = htonl((tv.tv_sec % 86400) * 1000 + |
| 815 | tv.tv_usec / 1000); |
| 816 | icmp_param.data.times[2] = icmp_param.data.times[1]; |
| 817 | if (skb_copy_bits(skb, 0, &icmp_param.data.times[0], 4)) |
| 818 | BUG(); |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 819 | icmp_param.data.icmph = *icmp_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | icmp_param.data.icmph.type = ICMP_TIMESTAMPREPLY; |
| 821 | icmp_param.data.icmph.code = 0; |
| 822 | icmp_param.skb = skb; |
| 823 | icmp_param.offset = 0; |
| 824 | icmp_param.data_len = 0; |
| 825 | icmp_param.head_len = sizeof(struct icmphdr) + 12; |
| 826 | icmp_reply(&icmp_param, skb); |
| 827 | out: |
| 828 | return; |
| 829 | out_err: |
| 830 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
| 831 | goto out; |
| 832 | } |
| 833 | |
| 834 | |
| 835 | /* |
| 836 | * Handle ICMP_ADDRESS_MASK requests. (RFC950) |
| 837 | * |
| 838 | * RFC1122 (3.2.2.9). A host MUST only send replies to |
| 839 | * ADDRESS_MASK requests if it's been configured as an address mask |
| 840 | * agent. Receiving a request doesn't constitute implicit permission to |
| 841 | * act as one. Of course, implementing this correctly requires (SHOULD) |
| 842 | * a way to turn the functionality on and off. Another one for sysctl(), |
| 843 | * I guess. -- MS |
| 844 | * |
| 845 | * RFC1812 (4.3.3.9). A router MUST implement it. |
| 846 | * A router SHOULD have switch turning it on/off. |
| 847 | * This switch MUST be ON by default. |
| 848 | * |
| 849 | * Gratuitous replies, zero-source replies are not implemented, |
| 850 | * that complies with RFC. DO NOT implement them!!! All the idea |
| 851 | * of broadcast addrmask replies as specified in RFC950 is broken. |
| 852 | * The problem is that it is not uncommon to have several prefixes |
| 853 | * on one physical interface. Moreover, addrmask agent can even be |
| 854 | * not aware of existing another prefixes. |
| 855 | * If source is zero, addrmask agent cannot choose correct prefix. |
| 856 | * Gratuitous mask announcements suffer from the same problem. |
| 857 | * RFC1812 explains it, but still allows to use ADDRMASK, |
| 858 | * that is pretty silly. --ANK |
| 859 | * |
| 860 | * All these rules are so bizarre, that I removed kernel addrmask |
| 861 | * support at all. It is wrong, it is obsolete, nobody uses it in |
| 862 | * any case. --ANK |
| 863 | * |
| 864 | * Furthermore you can do it with a usermode address agent program |
| 865 | * anyway... |
| 866 | */ |
| 867 | |
| 868 | static void icmp_address(struct sk_buff *skb) |
| 869 | { |
| 870 | #if 0 |
| 871 | if (net_ratelimit()) |
| 872 | printk(KERN_DEBUG "a guy asks for address mask. Who is it?\n"); |
| 873 | #endif |
| 874 | } |
| 875 | |
| 876 | /* |
| 877 | * RFC1812 (4.3.3.9). A router SHOULD listen all replies, and complain |
| 878 | * loudly if an inconsistency is found. |
| 879 | */ |
| 880 | |
| 881 | static void icmp_address_reply(struct sk_buff *skb) |
| 882 | { |
| 883 | struct rtable *rt = (struct rtable *)skb->dst; |
| 884 | struct net_device *dev = skb->dev; |
| 885 | struct in_device *in_dev; |
| 886 | struct in_ifaddr *ifa; |
| 887 | |
| 888 | if (skb->len < 4 || !(rt->rt_flags&RTCF_DIRECTSRC)) |
| 889 | goto out; |
| 890 | |
| 891 | in_dev = in_dev_get(dev); |
| 892 | if (!in_dev) |
| 893 | goto out; |
| 894 | rcu_read_lock(); |
| 895 | if (in_dev->ifa_list && |
| 896 | IN_DEV_LOG_MARTIANS(in_dev) && |
| 897 | IN_DEV_FORWARD(in_dev)) { |
Al Viro | a144ea4 | 2006-09-28 18:00:55 -0700 | [diff] [blame] | 898 | __be32 _mask, *mp; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | |
| 900 | mp = skb_header_pointer(skb, 0, sizeof(_mask), &_mask); |
Kris Katterjohn | 09a6266 | 2006-01-08 22:24:28 -0800 | [diff] [blame] | 901 | BUG_ON(mp == NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) { |
| 903 | if (*mp == ifa->ifa_mask && |
| 904 | inet_ifa_match(rt->rt_src, ifa)) |
| 905 | break; |
| 906 | } |
| 907 | if (!ifa && net_ratelimit()) { |
| 908 | printk(KERN_INFO "Wrong address mask %u.%u.%u.%u from " |
| 909 | "%s/%u.%u.%u.%u\n", |
| 910 | NIPQUAD(*mp), dev->name, NIPQUAD(rt->rt_src)); |
| 911 | } |
| 912 | } |
| 913 | rcu_read_unlock(); |
| 914 | in_dev_put(in_dev); |
| 915 | out:; |
| 916 | } |
| 917 | |
| 918 | static void icmp_discard(struct sk_buff *skb) |
| 919 | { |
| 920 | } |
| 921 | |
| 922 | /* |
| 923 | * Deal with incoming ICMP packets. |
| 924 | */ |
| 925 | int icmp_rcv(struct sk_buff *skb) |
| 926 | { |
| 927 | struct icmphdr *icmph; |
| 928 | struct rtable *rt = (struct rtable *)skb->dst; |
| 929 | |
| 930 | ICMP_INC_STATS_BH(ICMP_MIB_INMSGS); |
| 931 | |
| 932 | switch (skb->ip_summed) { |
Patrick McHardy | 84fa793 | 2006-08-29 16:44:56 -0700 | [diff] [blame] | 933 | case CHECKSUM_COMPLETE: |
Al Viro | d3bc23e | 2006-11-14 21:24:49 -0800 | [diff] [blame] | 934 | if (!csum_fold(skb->csum)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | break; |
Herbert Xu | fb286bb | 2005-11-10 13:01:24 -0800 | [diff] [blame] | 936 | /* fall through */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 937 | case CHECKSUM_NONE: |
Herbert Xu | fb286bb | 2005-11-10 13:01:24 -0800 | [diff] [blame] | 938 | skb->csum = 0; |
| 939 | if (__skb_checksum_complete(skb)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 940 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 941 | } |
| 942 | |
| 943 | if (!pskb_pull(skb, sizeof(struct icmphdr))) |
| 944 | goto error; |
| 945 | |
Arnaldo Carvalho de Melo | 88c7664 | 2007-03-13 14:43:18 -0300 | [diff] [blame^] | 946 | icmph = icmp_hdr(skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 947 | |
| 948 | /* |
| 949 | * 18 is the highest 'known' ICMP type. Anything else is a mystery |
| 950 | * |
| 951 | * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently |
| 952 | * discarded. |
| 953 | */ |
| 954 | if (icmph->type > NR_ICMP_TYPES) |
| 955 | goto error; |
| 956 | |
| 957 | |
| 958 | /* |
| 959 | * Parse the ICMP message |
| 960 | */ |
| 961 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 962 | if (rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 963 | /* |
| 964 | * RFC 1122: 3.2.2.6 An ICMP_ECHO to broadcast MAY be |
| 965 | * silently ignored (we let user decide with a sysctl). |
| 966 | * RFC 1122: 3.2.2.8 An ICMP_TIMESTAMP MAY be silently |
| 967 | * discarded if to broadcast/multicast. |
| 968 | */ |
Alexey Kuznetsov | 4c866aa | 2005-07-08 17:34:46 -0700 | [diff] [blame] | 969 | if ((icmph->type == ICMP_ECHO || |
| 970 | icmph->type == ICMP_TIMESTAMP) && |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | sysctl_icmp_echo_ignore_broadcasts) { |
| 972 | goto error; |
| 973 | } |
| 974 | if (icmph->type != ICMP_ECHO && |
| 975 | icmph->type != ICMP_TIMESTAMP && |
| 976 | icmph->type != ICMP_ADDRESS && |
| 977 | icmph->type != ICMP_ADDRESSREPLY) { |
| 978 | goto error; |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 979 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 980 | } |
| 981 | |
| 982 | ICMP_INC_STATS_BH(icmp_pointers[icmph->type].input_entry); |
| 983 | icmp_pointers[icmph->type].handler(skb); |
| 984 | |
| 985 | drop: |
| 986 | kfree_skb(skb); |
| 987 | return 0; |
| 988 | error: |
| 989 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
| 990 | goto drop; |
| 991 | } |
| 992 | |
| 993 | /* |
| 994 | * This table is the definition of how we handle ICMP. |
| 995 | */ |
Arjan van de Ven | 9b5b5cf | 2005-11-29 16:21:38 -0800 | [diff] [blame] | 996 | static const struct icmp_control icmp_pointers[NR_ICMP_TYPES + 1] = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 997 | [ICMP_ECHOREPLY] = { |
| 998 | .output_entry = ICMP_MIB_OUTECHOREPS, |
| 999 | .input_entry = ICMP_MIB_INECHOREPS, |
| 1000 | .handler = icmp_discard, |
| 1001 | }, |
| 1002 | [1] = { |
| 1003 | .output_entry = ICMP_MIB_DUMMY, |
| 1004 | .input_entry = ICMP_MIB_INERRORS, |
| 1005 | .handler = icmp_discard, |
| 1006 | .error = 1, |
| 1007 | }, |
| 1008 | [2] = { |
| 1009 | .output_entry = ICMP_MIB_DUMMY, |
| 1010 | .input_entry = ICMP_MIB_INERRORS, |
| 1011 | .handler = icmp_discard, |
| 1012 | .error = 1, |
| 1013 | }, |
| 1014 | [ICMP_DEST_UNREACH] = { |
| 1015 | .output_entry = ICMP_MIB_OUTDESTUNREACHS, |
| 1016 | .input_entry = ICMP_MIB_INDESTUNREACHS, |
| 1017 | .handler = icmp_unreach, |
| 1018 | .error = 1, |
| 1019 | }, |
| 1020 | [ICMP_SOURCE_QUENCH] = { |
| 1021 | .output_entry = ICMP_MIB_OUTSRCQUENCHS, |
| 1022 | .input_entry = ICMP_MIB_INSRCQUENCHS, |
| 1023 | .handler = icmp_unreach, |
| 1024 | .error = 1, |
| 1025 | }, |
| 1026 | [ICMP_REDIRECT] = { |
| 1027 | .output_entry = ICMP_MIB_OUTREDIRECTS, |
| 1028 | .input_entry = ICMP_MIB_INREDIRECTS, |
| 1029 | .handler = icmp_redirect, |
| 1030 | .error = 1, |
| 1031 | }, |
| 1032 | [6] = { |
| 1033 | .output_entry = ICMP_MIB_DUMMY, |
| 1034 | .input_entry = ICMP_MIB_INERRORS, |
| 1035 | .handler = icmp_discard, |
| 1036 | .error = 1, |
| 1037 | }, |
| 1038 | [7] = { |
| 1039 | .output_entry = ICMP_MIB_DUMMY, |
| 1040 | .input_entry = ICMP_MIB_INERRORS, |
| 1041 | .handler = icmp_discard, |
| 1042 | .error = 1, |
| 1043 | }, |
| 1044 | [ICMP_ECHO] = { |
| 1045 | .output_entry = ICMP_MIB_OUTECHOS, |
| 1046 | .input_entry = ICMP_MIB_INECHOS, |
| 1047 | .handler = icmp_echo, |
| 1048 | }, |
| 1049 | [9] = { |
| 1050 | .output_entry = ICMP_MIB_DUMMY, |
| 1051 | .input_entry = ICMP_MIB_INERRORS, |
| 1052 | .handler = icmp_discard, |
| 1053 | .error = 1, |
| 1054 | }, |
| 1055 | [10] = { |
| 1056 | .output_entry = ICMP_MIB_DUMMY, |
| 1057 | .input_entry = ICMP_MIB_INERRORS, |
| 1058 | .handler = icmp_discard, |
| 1059 | .error = 1, |
| 1060 | }, |
| 1061 | [ICMP_TIME_EXCEEDED] = { |
| 1062 | .output_entry = ICMP_MIB_OUTTIMEEXCDS, |
| 1063 | .input_entry = ICMP_MIB_INTIMEEXCDS, |
| 1064 | .handler = icmp_unreach, |
| 1065 | .error = 1, |
| 1066 | }, |
| 1067 | [ICMP_PARAMETERPROB] = { |
| 1068 | .output_entry = ICMP_MIB_OUTPARMPROBS, |
| 1069 | .input_entry = ICMP_MIB_INPARMPROBS, |
| 1070 | .handler = icmp_unreach, |
| 1071 | .error = 1, |
| 1072 | }, |
| 1073 | [ICMP_TIMESTAMP] = { |
| 1074 | .output_entry = ICMP_MIB_OUTTIMESTAMPS, |
| 1075 | .input_entry = ICMP_MIB_INTIMESTAMPS, |
| 1076 | .handler = icmp_timestamp, |
| 1077 | }, |
| 1078 | [ICMP_TIMESTAMPREPLY] = { |
| 1079 | .output_entry = ICMP_MIB_OUTTIMESTAMPREPS, |
| 1080 | .input_entry = ICMP_MIB_INTIMESTAMPREPS, |
| 1081 | .handler = icmp_discard, |
| 1082 | }, |
| 1083 | [ICMP_INFO_REQUEST] = { |
| 1084 | .output_entry = ICMP_MIB_DUMMY, |
| 1085 | .input_entry = ICMP_MIB_DUMMY, |
| 1086 | .handler = icmp_discard, |
| 1087 | }, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 1088 | [ICMP_INFO_REPLY] = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1089 | .output_entry = ICMP_MIB_DUMMY, |
| 1090 | .input_entry = ICMP_MIB_DUMMY, |
| 1091 | .handler = icmp_discard, |
| 1092 | }, |
| 1093 | [ICMP_ADDRESS] = { |
| 1094 | .output_entry = ICMP_MIB_OUTADDRMASKS, |
| 1095 | .input_entry = ICMP_MIB_INADDRMASKS, |
| 1096 | .handler = icmp_address, |
| 1097 | }, |
| 1098 | [ICMP_ADDRESSREPLY] = { |
| 1099 | .output_entry = ICMP_MIB_OUTADDRMASKREPS, |
| 1100 | .input_entry = ICMP_MIB_INADDRMASKREPS, |
| 1101 | .handler = icmp_address_reply, |
| 1102 | }, |
| 1103 | }; |
| 1104 | |
| 1105 | void __init icmp_init(struct net_proto_family *ops) |
| 1106 | { |
| 1107 | struct inet_sock *inet; |
| 1108 | int i; |
| 1109 | |
KAMEZAWA Hiroyuki | 6f91204 | 2006-04-10 22:52:50 -0700 | [diff] [blame] | 1110 | for_each_possible_cpu(i) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1111 | int err; |
| 1112 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | err = sock_create_kern(PF_INET, SOCK_RAW, IPPROTO_ICMP, |
| 1114 | &per_cpu(__icmp_socket, i)); |
| 1115 | |
| 1116 | if (err < 0) |
| 1117 | panic("Failed to create the ICMP control socket.\n"); |
| 1118 | |
| 1119 | per_cpu(__icmp_socket, i)->sk->sk_allocation = GFP_ATOMIC; |
| 1120 | |
| 1121 | /* Enough space for 2 64K ICMP packets, including |
| 1122 | * sk_buff struct overhead. |
| 1123 | */ |
| 1124 | per_cpu(__icmp_socket, i)->sk->sk_sndbuf = |
| 1125 | (2 * ((64 * 1024) + sizeof(struct sk_buff))); |
| 1126 | |
| 1127 | inet = inet_sk(per_cpu(__icmp_socket, i)->sk); |
| 1128 | inet->uc_ttl = -1; |
| 1129 | inet->pmtudisc = IP_PMTUDISC_DONT; |
| 1130 | |
| 1131 | /* Unhash it so that IP input processing does not even |
| 1132 | * see it, we do not wish this socket to see incoming |
| 1133 | * packets. |
| 1134 | */ |
| 1135 | per_cpu(__icmp_socket, i)->sk->sk_prot->unhash(per_cpu(__icmp_socket, i)->sk); |
| 1136 | } |
| 1137 | } |
| 1138 | |
| 1139 | EXPORT_SYMBOL(icmp_err_convert); |
| 1140 | EXPORT_SYMBOL(icmp_send); |
| 1141 | EXPORT_SYMBOL(icmp_statistics); |
| 1142 | EXPORT_SYMBOL(xrlim_allow); |