net/inet/icmp.c

/* */
This source file includes following definitions.
print_icmp
icmp_send
icmp_unreach
icmp_redirect
icmp_echo
icmp_info
icmp_address
icmp_rcv
icmp_ioctl
   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Internet Control Message Protocol (ICMP)
   7  *
   8  * Version:     @(#)icmp.c      1.0.11  06/02/93
   9  *
  10  * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Mark Evans, <evansmp@uhura.aston.ac.uk>
  13  *
  14  *              This program is free software; you can redistribute it and/or
  15  *              modify it under the terms of the GNU General Public License
  16  *              as published by the Free Software Foundation; either version
  17  *              2 of the License, or (at your option) any later version.
  18  */
  19 #include <linux/types.h>
  20 #include <linux/sched.h>
  21 #include <linux/kernel.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/socket.h>
  24 #include <linux/in.h>
  25 #include "inet.h"
  26 #include "timer.h"
  27 #include "dev.h"
  28 #include "ip.h"
  29 #include "route.h"
  30 #include "protocol.h"
  31 #include "icmp.h"
  32 #include "tcp.h"
  33 #include "skbuff.h"
  34 #include "sock.h"
  35 #include <linux/errno.h>
  36 #include <linux/timer.h>
  37 #include <asm/system.h>
  38 #include <asm/segment.h>
  39 
  40 
  41 #define min(a,b)        ((a)<(b)?(a):(b))
  42 
  43 
  44 /* An array of errno for error messages from dest unreach. */
  45 struct icmp_err icmp_err_convert[] = {
  46   { ENETUNREACH,        1 },
  47   { EHOSTUNREACH,       1 },
  48   { ENOPROTOOPT,        1 },
  49   { ECONNREFUSED,       1 },
  50   { EOPNOTSUPP,         0 },
  51   { EOPNOTSUPP,         0 },
  52   { ENETUNREACH,        1 },
  53   { EHOSTDOWN,          1 },
  54   { ENONET,             1 },
  55   { ENETUNREACH,        1 },
  56   { EHOSTUNREACH,       1 },
  57   { EOPNOTSUPP,         0 },
  58   { EOPNOTSUPP,         0 }
  59 };
  60 
  61 
  62 /* Display the contents of an ICMP header. */
  63 static void
  64 print_icmp(struct icmphdr *icmph)
     /*  */
  65 {
  66   if (inet_debug != DBG_ICMP) return;
  67 
  68   printk("ICMP: type = %d, code = %d, checksum = %X\n",
  69                         icmph->type, icmph->code, icmph->checksum);
  70   printk("      gateway = %s\n", in_ntoa(icmph->un.gateway));
  71 }
  72 
  73 
  74 /* Send an ICMP message. */
  75 void
  76 icmp_send(struct sk_buff *skb_in, int type, int code, struct device *dev)
     /*  */
  77 {
  78   struct sk_buff *skb;
  79   struct iphdr *iph;
  80   int offset;
  81   struct icmphdr *icmph;
  82   int len;
  83 
  84   DPRINTF((DBG_ICMP, "icmp_send(skb_in = %X, type = %d, code = %d, dev=%X)\n",
  85                                                 skb_in, type, code, dev));
  86 
  87   /* Get some memory for the reply. */
  88   len = sizeof(struct sk_buff) + dev->hard_header_len +
  89         sizeof(struct iphdr) + sizeof(struct icmphdr) +
  90         sizeof(struct iphdr) + 8;       /* amount of header to return */
  91            
  92   skb = (struct sk_buff *) kmalloc(len, GFP_ATOMIC);
  93   if (skb == NULL) return;
  94 
  95   skb->lock = 0;
  96   skb->sk = NULL;
  97   skb->mem_addr = skb;
  98   skb->mem_len = len;
  99   len -= sizeof(struct sk_buff);
 100 
 101   /* Find the IP header. */
 102   iph = (struct iphdr *) (skb_in + 1);
 103   iph = (struct iphdr *) ((unsigned char *) iph + dev->hard_header_len);
 104 
 105   /* Build Layer 2-3 headers for message back to source. */
 106   offset = ip_build_header(skb, iph->daddr, iph->saddr,
 107                            &dev, IPPROTO_ICMP, NULL, len);
 108   if (offset < 0) {
 109         skb->sk = NULL;
 110         kfree_skb(skb, FREE_READ);
 111         return;
 112   }
 113 
 114   /* Re-adjust length according to actual IP header size. */
 115   skb->len = offset + sizeof(struct icmphdr) + sizeof(struct iphdr) + 8;
 116   icmph = (struct icmphdr *) ((unsigned char *) (skb + 1) + offset);
 117   icmph->type = type;
 118   icmph->code = code;
 119   icmph->checksum = 0;
 120   icmph->un.gateway = 0;
 121   memcpy(icmph + 1, iph, sizeof(struct iphdr) + 8);
 122 
 123   icmph->checksum = ip_compute_csum((unsigned char *)icmph,
 124                          sizeof(struct icmphdr) + sizeof(struct iphdr) + 8);
 125 
 126   DPRINTF((DBG_ICMP, ">>\n"));
 127   print_icmp(icmph);
 128 
 129   /* Send it and free it. */
 130   ip_queue_xmit(NULL, dev, skb, 1);
 131 }
 132 
 133 
 134 /* Handle ICMP_UNREACH and ICMP_QUENCH. */
 135 static void
 136 icmp_unreach(struct icmphdr *icmph, struct sk_buff *skb)
     /*  */
 137 {
 138   struct inet_protocol *ipprot;
 139   struct iphdr *iph;
 140   unsigned char hash;
 141   int err;
 142 
 143   err = (icmph->type << 8) | icmph->code;
 144   iph = (struct iphdr *) (icmph + 1);
 145   switch(icmph->code & 7) {
 146         case ICMP_NET_UNREACH:
 147                 DPRINTF((DBG_ICMP, "ICMP: %s: network unreachable.\n",
 148                                                         in_ntoa(iph->daddr)));
 149                 break;
 150         case ICMP_HOST_UNREACH:
 151                 DPRINTF((DBG_ICMP, "ICMP: %s: host unreachable.\n",
 152                                                 in_ntoa(iph->daddr)));
 153                 break;
 154         case ICMP_PROT_UNREACH:
 155                 printk("ICMP: %s:%d: protocol unreachable.\n",
 156                         in_ntoa(iph->daddr), ntohs(iph->protocol));
 157                 break;
 158         case ICMP_PORT_UNREACH:
 159                 DPRINTF((DBG_ICMP, "ICMP: %s:%d: port unreachable.\n",
 160                         in_ntoa(iph->daddr), -1 /* FIXME: ntohs(iph->port) */));
 161                 break;
 162         case ICMP_FRAG_NEEDED:
 163                 printk("ICMP: %s: fragmentation needed and DF set.\n",
 164                                                         in_ntoa(iph->daddr));
 165                 break;
 166         case ICMP_SR_FAILED:
 167                 printk("ICMP: %s: Source Route Failed.\n", in_ntoa(iph->daddr));
 168                 break;
 169         default:
 170                 DPRINTF((DBG_ICMP, "ICMP: Unreachable: CODE=%d from %s\n",
 171                                 (icmph->code & 7), in_ntoa(iph->daddr)));
 172                 break;
 173   }
 174 
 175   /* Get the protocol(s). */
 176   hash = iph->protocol & (MAX_INET_PROTOS -1);
 177 
 178   /* This can change while we are doing it. */
 179   ipprot = (struct inet_protocol *) inet_protos[hash];
 180   while(ipprot != NULL) {
 181         struct inet_protocol *nextip;
 182 
 183         nextip = (struct inet_protocol *) ipprot->next;
 184 
 185         /* Pass it off to everyone who wants it. */
 186         if (iph->protocol == ipprot->protocol && ipprot->err_handler) {
 187                 ipprot->err_handler(err, (unsigned char *)(icmph + 1),
 188                                     iph->daddr, iph->saddr, ipprot);
 189         }
 190 
 191         ipprot = nextip;
 192   }
 193   skb->sk = NULL;
 194   kfree_skb(skb, FREE_READ);
 195 }
 196 
 197 
 198 /* Handle ICMP_REDIRECT. */
 199 static void
 200 icmp_redirect(struct icmphdr *icmph, struct sk_buff *skb, struct device *dev)
     /*  */
 201 {
 202   struct iphdr *iph;
 203   unsigned long ip;
 204 
 205   iph = (struct iphdr *) (icmph + 1);
 206   ip = iph->daddr;
 207   switch(icmph->code & 7) {
 208         case ICMP_REDIR_NET:
 209                 rt_add((RTF_DYNAMIC | RTF_MODIFIED),
 210                         ip, icmph->un.gateway, dev);
 211                 break;
 212         case ICMP_REDIR_HOST:
 213                 rt_add((RTF_DYNAMIC | RTF_MODIFIED | RTF_HOST),
 214                         ip, icmph->un.gateway, dev);
 215                 break;
 216         case ICMP_REDIR_NETTOS:
 217         case ICMP_REDIR_HOSTTOS:
 218                 printk("ICMP: cannot handle TOS redirects yet!\n");
 219                 break;
 220         default:
 221                 DPRINTF((DBG_ICMP, "ICMP: Unreach: CODE=%d\n",
 222                                                 (icmph->code & 7)));
 223                 break;
 224   }
 225   skb->sk = NULL;
 226   kfree_skb(skb, FREE_READ);
 227 }
 228 
 229 
 230 /* Handle ICMP_ECHO ("ping") requests. */
 231 static void
 232 icmp_echo(struct icmphdr *icmph, struct sk_buff *skb, struct device *dev,
     /*  */
 233           unsigned long saddr, unsigned long daddr, int len,
 234           struct options *opt)
 235 {
 236   struct icmphdr *icmphr;
 237   struct sk_buff *skb2;
 238   int size, offset;
 239 
 240   size = sizeof(struct sk_buff) + dev->hard_header_len + 64 + len;
 241   skb2 = (struct sk_buff *) kmalloc(size, GFP_ATOMIC);
 242   if (skb2 == NULL) {
 243         skb->sk = NULL;
 244         kfree_skb(skb, FREE_READ);
 245         return;
 246   }
 247   skb2->sk = NULL;
 248   skb2->lock = 0;
 249   skb2->mem_addr = skb2;
 250   skb2->mem_len = size;
 251 
 252   /* Build Layer 2-3 headers for message back to source */
 253   offset = ip_build_header(skb2, daddr, saddr, &dev,
 254                                 IPPROTO_ICMP, opt, len);
 255   if (offset < 0) {
 256         printk("ICMP: Could not build IP Header for ICMP ECHO Response\n");
 257         kfree_s(skb2->mem_addr, skb2->mem_len);
 258         skb->sk = NULL;
 259         kfree_skb(skb, FREE_READ);
 260         return;
 261   }
 262 
 263   /* Re-adjust length according to actual IP header size. */
 264   skb2->len = offset + len;
 265 
 266   /* Build ICMP_ECHO Response message. */
 267   icmphr = (struct icmphdr *) ((char *) (skb2 + 1) + offset);
 268   memcpy((char *) icmphr, (char *) icmph, len);
 269   icmphr->type = ICMP_ECHOREPLY;
 270   icmphr->code = 0;
 271   icmphr->checksum = 0;
 272 
 273   if (icmph->checksum) {        /* Calculate Checksum */
 274         icmphr->checksum = ip_compute_csum((unsigned char *)icmphr, len);
 275   }
 276 
 277   /* Ship it out - free it when done */
 278   ip_queue_xmit((struct sock *)NULL, dev, skb2, 1);
 279 
 280   skb->sk = NULL;
 281   kfree_skb(skb, FREE_READ);
 282 }
 283 
 284 
 285 /* Handle the ICMP INFORMATION REQUEST. */
 286 static void
 287 icmp_info(struct icmphdr *icmph, struct sk_buff *skb, struct device *dev,
     /*  */
 288           unsigned long saddr, unsigned long daddr, int len,
 289           struct options *opt)
 290 {
 291   /* NOT YET */
 292   skb->sk = NULL;
 293   kfree_skb(skb, FREE_READ);
 294 }
 295 
 296 
 297 /* Handle ICMP_ADRESS_MASK requests. */
 298 static void
 299 icmp_address(struct icmphdr *icmph, struct sk_buff *skb, struct device *dev,
     /*  */
 300           unsigned long saddr, unsigned long daddr, int len,
 301           struct options *opt)
 302 {
 303   struct icmphdr *icmphr;
 304   struct sk_buff *skb2;
 305   int size, offset;
 306 
 307   size = sizeof(struct sk_buff) + dev->hard_header_len + 64 + len;
 308   skb2 = (struct sk_buff *) kmalloc(size, GFP_ATOMIC);
 309   if (skb2 == NULL) {
 310         skb->sk = NULL;
 311         kfree_skb(skb, FREE_READ);
 312         return;
 313   }
 314   skb2->sk = NULL;
 315   skb2->lock = 0;
 316   skb2->mem_addr = skb2;
 317   skb2->mem_len = size;
 318 
 319   /* Build Layer 2-3 headers for message back to source */
 320   offset = ip_build_header(skb2, daddr, saddr, &dev,
 321                                 IPPROTO_ICMP, opt, len);
 322   if (offset < 0) {
 323         printk("ICMP: Could not build IP Header for ICMP ADDRESS Response\n");
 324         kfree_s(skb2->mem_addr, skb2->mem_len);
 325         skb->sk = NULL;
 326         kfree_skb(skb, FREE_READ);
 327         return;
 328   }
 329 
 330   /* Re-adjust length according to actual IP header size. */
 331   skb2->len = offset + len;
 332 
 333   /* Build ICMP ADDRESS MASK Response message. */
 334   icmphr = (struct icmphdr *) ((char *) (skb2 + 1) + offset);
 335   icmphr->type = ICMP_ADDRESSREPLY;
 336   icmphr->code = 0;
 337   icmphr->checksum = 0;
 338   icmphr->un.echo.id = icmph->un.echo.id;
 339   icmphr->un.echo.sequence = icmph->un.echo.sequence;
 340   memcpy((char *) (icmphr + 1), (char *) &dev->pa_mask, sizeof(dev->pa_mask));
 341 
 342   if (icmph->checksum) {        /* Calculate Checksum */
 343         icmphr->checksum = ip_compute_csum((unsigned char *)icmphr, len);
 344   }
 345 
 346   /* Ship it out - free it when done */
 347   ip_queue_xmit((struct sock *)NULL, dev, skb2, 1);
 348 
 349   skb->sk = NULL;
 350   kfree_skb(skb, FREE_READ);
 351 }
 352 
 353 
 354 /* Deal with incoming ICMP packets. */
 355 int
 356 icmp_rcv(struct sk_buff *skb1, struct device *dev, struct options *opt,
     /*  */
 357          unsigned long daddr, unsigned short len,
 358          unsigned long saddr, int redo, struct inet_protocol *protocol)
 359 {
 360   struct icmphdr *icmph;
 361   unsigned char *buff;
 362 
 363   /* Drop broadcast packets. */
 364   if (chk_addr(daddr) == IS_BROADCAST) {
 365         DPRINTF((DBG_ICMP, "ICMP: Discarded broadcast from %s\n",
 366                                                         in_ntoa(saddr)));
 367         skb1->sk = NULL;
 368         kfree_skb(skb1, FREE_READ);
 369         return(0);
 370   }
 371 
 372   buff = skb1->h.raw;
 373   icmph = (struct icmphdr *) buff;
 374 
 375   /* Validate the packet first */
 376   if (icmph->checksum) {        /* Checksums Enabled? */
 377         if (ip_compute_csum((unsigned char *) icmph, len)) {
 378                 /* Failed checksum! */
 379                 printk("ICMP: failed checksum from %s!\n", in_ntoa(saddr));
 380                 skb1->sk = NULL;
 381                 kfree_skb(skb1, FREE_READ);
 382                 return(0);
 383         }
 384   }
 385   print_icmp(icmph);
 386 
 387   /* Parse the ICMP message */
 388   switch(icmph->type) {
 389         case ICMP_TIME_EXCEEDED:
 390         case ICMP_DEST_UNREACH:
 391         case ICMP_SOURCE_QUENCH:
 392                 icmp_unreach(icmph, skb1);
 393                 return(0);
 394         case ICMP_REDIRECT:
 395                 icmp_redirect(icmph, skb1, dev);
 396                 return(0);
 397         case ICMP_ECHO: 
 398                 icmp_echo(icmph, skb1, dev, saddr, daddr, len, opt);
 399                 return 0;
 400         case ICMP_ECHOREPLY:
 401                 skb1->sk = NULL;
 402                 kfree_skb(skb1, FREE_READ);
 403                 return(0);
 404         case ICMP_INFO_REQUEST:
 405                 icmp_info(icmph, skb1, dev, saddr, daddr, len, opt);
 406                 return 0;
 407         case ICMP_INFO_REPLY:
 408                 skb1->sk = NULL;
 409                 kfree_skb(skb1, FREE_READ);
 410                 return(0);
 411         case ICMP_ADDRESS:
 412                 icmp_address(icmph, skb1, dev, saddr, daddr, len, opt);
 413                 return 0;
 414         case ICMP_ADDRESSREPLY:
 415                 skb1->sk = NULL;
 416                 kfree_skb(skb1, FREE_READ);
 417                 return(0);
 418         default:
 419                 DPRINTF((DBG_ICMP,
 420                         "ICMP: Unsupported ICMP from %s, type = 0x%X\n",
 421                                                 in_ntoa(saddr), icmph->type));
 422                 skb1->sk = NULL;
 423                 kfree_skb(skb1, FREE_READ);
 424                 return(0);
 425   }
 426   /*NOTREACHED*/
 427   skb1->sk = NULL;
 428   kfree_skb(skb1, FREE_READ);
 429   return(-1);
 430 }
 431 
 432 
 433 /* Perform any ICMP-related I/O control requests. */
 434 int
 435 icmp_ioctl(struct sock *sk, int cmd, unsigned long arg)
     /*  */
 436 {
 437   switch(cmd) {
 438         case DDIOCSDBG:
 439                 return(dbg_ioctl((void *) arg, DBG_ICMP));
 440         default:
 441                 return(-EINVAL);
 442   }
 443   return(0);
 444 }
/* */
root/net/inet/icmp.c

DEFINITIONS
