net/ipv6/netfilter/ip6t_LOG.c

   1 /*
   2  * This is a module which is used for logging packets.
   3  */
   4
   5 /* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
   6  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/ip.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/icmpv6.h>
  19 #include <net/udp.h>
  20 #include <net/tcp.h>
  21 #include <net/ipv6.h>
  22 #include <linux/netfilter.h>
  23 #include <linux/netfilter_ipv6/ip6_tables.h>
  24
  25 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
  26 MODULE_DESCRIPTION("IP6 tables LOG target module");
  27 MODULE_LICENSE("GPL");
  28
  29 static unsigned int nflog = 1;
  30 module_param(nflog, int, 0400);
  31 MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
  32
  33 struct in_device;
  34 #include <net/route.h>
  35 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  36
  37 #if 0
  38 #define DEBUGP printk
  39 #else
  40 #define DEBUGP(format, args...)
  41 #endif
  42
  43 /* Use lock to serialize, so printks don't overlap */
  44 static spinlock_t log_lock = SPIN_LOCK_UNLOCKED;
  45
  46 /* One level of recursion won't kill us */
  47 static void dump_packet(const struct ip6t_log_info *info,
  48                         const struct sk_buff *skb, unsigned int ip6hoff,
  49                         int recurse)
  50 {
  51         u_int8_t currenthdr;
  52         int fragment;
  53         struct ipv6hdr _ip6h, *ih;
  54         unsigned int ptr;
  55         unsigned int hdrlen = 0;
  56
  57         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  58         if (ih == NULL) {
  59                 printk("TRUNCATED");
  60                 return;
  61         }
  62
  63         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000" */
  64         printk("SRC=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ih->saddr));
  65         printk("DST=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ih->daddr));
  66
  67         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  68         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  69                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  70                (ntohl(*(u_int32_t *)ih) & 0x0ff00000) >> 20,
  71                ih->hop_limit,
  72                (ntohl(*(u_int32_t *)ih) & 0x000fffff));
  73
  74         fragment = 0;
  75         ptr = ip6hoff + sizeof(struct ipv6hdr);
  76         currenthdr = ih->nexthdr;
  77         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  78                 struct ipv6_opt_hdr _hdr, *hp;
  79
  80                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  81                 if (hp == NULL) {
  82                         printk("TRUNCATED");
  83                         return;
  84                 }
  85
  86                 /* Max length: 48 "OPT (...) " */
  87                 if (info->logflags & IP6T_LOG_IPOPT)
  88                         printk("OPT ( ");
  89
  90                 switch (currenthdr) {
  91                 case IPPROTO_FRAGMENT: {
  92                         struct frag_hdr _fhdr, *fh;
  93
  94                         printk("FRAG:");
  95                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  96                                                 &_fhdr);
  97                         if (fh == NULL) {
  98                                 printk("TRUNCATED ");
  99                                 return;
 100                         }
 101
 102                         /* Max length: 6 "65535 " */
 103                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
 104
 105                         /* Max length: 11 "INCOMPLETE " */
 106                         if (fh->frag_off & htons(0x0001))
 107                                 printk("INCOMPLETE ");
 108
 109                         printk("ID:%08x ", ntohl(fh->identification));
 110
 111                         if (ntohs(fh->frag_off) & 0xFFF8)
 112                                 fragment = 1;
 113
 114                         hdrlen = 8;
 115
 116                         break;
 117                 }
 118                 case IPPROTO_DSTOPTS:
 119                 case IPPROTO_ROUTING:
 120                 case IPPROTO_HOPOPTS:
 121                         if (fragment) {
 122                                 if (info->logflags & IP6T_LOG_IPOPT)
 123                                         printk(")");
 124                                 return;
 125                         }
 126                         hdrlen = ipv6_optlen(hp);
 127                         break;
 128                 /* Max Length */
 129                 case IPPROTO_AH:
 130                         if (info->logflags & IP6T_LOG_IPOPT) {
 131                                 struct ip_auth_hdr _ahdr, *ah;
 132
 133                                 /* Max length: 3 "AH " */
 134                                 printk("AH ");
 135
 136                                 if (fragment) {
 137                                         printk(")");
 138                                         return;
 139                                 }
 140
 141                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 142                                                         &_ahdr);
 143                                 if (ah == NULL) {
 144                                         /*
 145                                          * Max length: 26 "INCOMPLETE [65535
 146                                          *  bytes] )"
 147                                          */
 148                                         printk("INCOMPLETE [%u bytes] )",
 149                                                skb->len - ptr);
 150                                         return;
 151                                 }
 152
 153                                 /* Length: 15 "SPI=0xF1234567 */
 154                                 printk("SPI=0x%x ", ntohl(ah->spi));
 155
 156                         }
 157
 158                         hdrlen = (hp->hdrlen+2)<<2;
 159                         break;
 160                 case IPPROTO_ESP:
 161                         if (info->logflags & IP6T_LOG_IPOPT) {
 162                                 struct ip_esp_hdr _esph, *eh;
 163
 164                                 /* Max length: 4 "ESP " */
 165                                 printk("ESP ");
 166
 167                                 if (fragment) {
 168                                         printk(")");
 169                                         return;
 170                                 }
 171
 172                                 /*
 173                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 174                                  */
 175                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 176                                                         &_esph);
 177                                 if (eh == NULL) {
 178                                         printk("INCOMPLETE [%u bytes] )",
 179                                                skb->len - ptr);
 180                                         return;
 181                                 }
 182
 183                                 /* Length: 16 "SPI=0xF1234567 )" */
 184                                 printk("SPI=0x%x )", ntohl(eh->spi) );
 185
 186                         }
 187                         return;
 188                 default:
 189                         /* Max length: 20 "Unknown Ext Hdr 255" */
 190                         printk("Unknown Ext Hdr %u", currenthdr);
 191                         return;
 192                 }
 193                 if (info->logflags & IP6T_LOG_IPOPT)
 194                         printk(") ");
 195
 196                 currenthdr = hp->nexthdr;
 197                 ptr += hdrlen;
 198         }
 199
 200         switch (currenthdr) {
 201         case IPPROTO_TCP: {
 202                 struct tcphdr _tcph, *th;
 203
 204                 /* Max length: 10 "PROTO=TCP " */
 205                 printk("PROTO=TCP ");
 206
 207                 if (fragment)
 208                         break;
 209
 210                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 211                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
 212                 if (th == NULL) {
 213                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 214                         return;
 215                 }
 216
 217                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 218                 printk("SPT=%u DPT=%u ",
 219                        ntohs(th->source), ntohs(th->dest));
 220                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 221                 if (info->logflags & IP6T_LOG_TCPSEQ)
 222                         printk("SEQ=%u ACK=%u ",
 223                                ntohl(th->seq), ntohl(th->ack_seq));
 224                 /* Max length: 13 "WINDOW=65535 " */
 225                 printk("WINDOW=%u ", ntohs(th->window));
 226                 /* Max length: 9 "RES=0x3C " */
 227                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
 228                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 229                 if (th->cwr)
 230                         printk("CWR ");
 231                 if (th->ece)
 232                         printk("ECE ");
 233                 if (th->urg)
 234                         printk("URG ");
 235                 if (th->ack)
 236                         printk("ACK ");
 237                 if (th->psh)
 238                         printk("PSH ");
 239                 if (th->rst)
 240                         printk("RST ");
 241                 if (th->syn)
 242                         printk("SYN ");
 243                 if (th->fin)
 244                         printk("FIN ");
 245                 /* Max length: 11 "URGP=65535 " */
 246                 printk("URGP=%u ", ntohs(th->urg_ptr));
 247
 248                 if ((info->logflags & IP6T_LOG_TCPOPT)
 249                     && th->doff * 4 > sizeof(struct tcphdr)) {
 250                         u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
 251                         unsigned int i;
 252                         unsigned int optsize = th->doff * 4
 253                                                - sizeof(struct tcphdr);
 254
 255                         op = skb_header_pointer(skb,
 256                                                 ptr + sizeof(struct tcphdr),
 257                                                 optsize, _opt);
 258                         if (op == NULL) {
 259                                 printk("OPT (TRUNCATED)");
 260                                 return;
 261                         }
 262
 263                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
 264                         printk("OPT (");
 265                         for (i =0; i < optsize; i++)
 266                                 printk("%02X", op[i]);
 267                         printk(") ");
 268                 }
 269                 break;
 270         }
 271         case IPPROTO_UDP: {
 272                 struct udphdr _udph, *uh;
 273
 274                 /* Max length: 10 "PROTO=UDP " */
 275                 printk("PROTO=UDP ");
 276
 277                 if (fragment)
 278                         break;
 279
 280                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 281                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 282                 if (uh == NULL) {
 283                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 284                         return;
 285                 }
 286
 287                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 288                 printk("SPT=%u DPT=%u LEN=%u ",
 289                        ntohs(uh->source), ntohs(uh->dest),
 290                        ntohs(uh->len));
 291                 break;
 292         }
 293         case IPPROTO_ICMPV6: {
 294                 struct icmp6hdr _icmp6h, *ic;
 295
 296                 /* Max length: 13 "PROTO=ICMPv6 " */
 297                 printk("PROTO=ICMPv6 ");
 298
 299                 if (fragment)
 300                         break;
 301
 302                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 303                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 304                 if (ic == NULL) {
 305                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 306                         return;
 307                 }
 308
 309                 /* Max length: 18 "TYPE=255 CODE=255 " */
 310                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 311
 312                 switch (ic->icmp6_type) {
 313                 case ICMPV6_ECHO_REQUEST:
 314                 case ICMPV6_ECHO_REPLY:
 315                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 316                         printk("ID=%u SEQ=%u ",
 317                                 ntohs(ic->icmp6_identifier),
 318                                 ntohs(ic->icmp6_sequence));
 319                         break;
 320                 case ICMPV6_MGM_QUERY:
 321                 case ICMPV6_MGM_REPORT:
 322                 case ICMPV6_MGM_REDUCTION:
 323                         break;
 324
 325                 case ICMPV6_PARAMPROB:
 326                         /* Max length: 17 "POINTER=ffffffff " */
 327                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
 328                         /* Fall through */
 329                 case ICMPV6_DEST_UNREACH:
 330                 case ICMPV6_PKT_TOOBIG:
 331                 case ICMPV6_TIME_EXCEED:
 332                         /* Max length: 3+maxlen */
 333                         if (recurse) {
 334                                 printk("[");
 335                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
 336                                             0);
 337                                 printk("] ");
 338                         }
 339
 340                         /* Max length: 10 "MTU=65535 " */
 341                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 342                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 343                 }
 344                 break;
 345         }
 346         /* Max length: 10 "PROTO=255 " */
 347         default:
 348                 printk("PROTO=%u ", currenthdr);
 349         }
 350 }
 351
 352 static void
 353 ip6t_log_packet(unsigned int hooknum,
 354                 const struct sk_buff *skb,
 355                 const struct net_device *in,
 356                 const struct net_device *out,
 357                 const struct ip6t_log_info *loginfo,
 358                 const char *level_string,
 359                 const char *prefix)
 360 {
 361         struct ipv6hdr *ipv6h = skb->nh.ipv6h;
 362
 363         spin_lock_bh(&log_lock);
 364         printk(level_string);
 365         printk("%sIN=%s OUT=%s ",
 366                 prefix == NULL ? loginfo->prefix : prefix,
 367                 in ? in->name : "",
 368                 out ? out->name : "");
 369         if (in && !out) {
 370                 /* MAC logging for input chain only. */
 371                 printk("MAC=");
 372                 if (skb->dev && skb->dev->hard_header_len && skb->mac.raw != (void*)ipv6h) {
 373                         if (skb->dev->type != ARPHRD_SIT){
 374                           int i;
 375                           unsigned char *p = skb->mac.raw;
 376                           for (i = 0; i < skb->dev->hard_header_len; i++,p++)
 377                                 printk("%02x%c", *p,
 378                                         i==skb->dev->hard_header_len - 1
 379                                         ? ' ':':');
 380                         } else {
 381                           int i;
 382                           unsigned char *p = skb->mac.raw;
 383                           if ( p - (ETH_ALEN*2+2) > skb->head ){
 384                             p -= (ETH_ALEN+2);
 385                             for (i = 0; i < (ETH_ALEN); i++,p++)
 386                                 printk("%02x%s", *p,
 387                                         i == ETH_ALEN-1 ? "->" : ":");
 388                             p -= (ETH_ALEN*2);
 389                             for (i = 0; i < (ETH_ALEN); i++,p++)
 390                                 printk("%02x%c", *p,
 391                                         i == ETH_ALEN-1 ? ' ' : ':');
 392                           }
 393
 394                           if ((skb->dev->addr_len == 4) &&
 395                               skb->dev->hard_header_len > 20){
 396                             printk("TUNNEL=");
 397                             p = skb->mac.raw + 12;
 398                             for (i = 0; i < 4; i++,p++)
 399                                 printk("%3d%s", *p,
 400                                         i == 3 ? "->" : ".");
 401                             for (i = 0; i < 4; i++,p++)
 402                                 printk("%3d%c", *p,
 403                                         i == 3 ? ' ' : '.');
 404                           }
 405                         }
 406                 } else
 407                         printk(" ");
 408         }
 409
 410         dump_packet(loginfo, skb, (u8*)skb->nh.ipv6h - skb->data, 1);
 411         printk("\n");
 412         spin_unlock_bh(&log_lock);
 413 }
 414
 415 static unsigned int
 416 ip6t_log_target(struct sk_buff **pskb,
 417                 const struct net_device *in,
 418                 const struct net_device *out,
 419                 unsigned int hooknum,
 420                 const void *targinfo,
 421                 void *userinfo)
 422 {
 423         const struct ip6t_log_info *loginfo = targinfo;
 424         char level_string[4] = "< >";
 425
 426         level_string[1] = '0' + (loginfo->level % 8);
 427         ip6t_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL);
 428
 429         return IP6T_CONTINUE;
 430 }
 431
 432 static void
 433 ip6t_logfn(unsigned int hooknum,
 434            const struct sk_buff *skb,
 435            const struct net_device *in,
 436            const struct net_device *out,
 437            const char *prefix)
 438 {
 439         struct ip6t_log_info loginfo = {
 440                 .level = 0,
 441                 .logflags = IP6T_LOG_MASK,
 442                 .prefix = ""
 443         };
 444
 445         ip6t_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix);
 446 }
 447
 448 static int ip6t_log_checkentry(const char *tablename,
 449                                const struct ip6t_entry *e,
 450                                void *targinfo,
 451                                unsigned int targinfosize,
 452                                unsigned int hook_mask)
 453 {
 454         const struct ip6t_log_info *loginfo = targinfo;
 455
 456         if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_log_info))) {
 457                 DEBUGP("LOG: targinfosize %u != %u\n",
 458                        targinfosize, IP6T_ALIGN(sizeof(struct ip6t_log_info)));
 459                 return 0;
 460         }
 461
 462         if (loginfo->level >= 8) {
 463                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 464                 return 0;
 465         }
 466
 467         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 468                 DEBUGP("LOG: prefix term %i\n",
 469                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
 470                 return 0;
 471         }
 472
 473         return 1;
 474 }
 475
 476 static struct ip6t_target ip6t_log_reg = {
 477         .name           = "LOG",
 478         .target         = ip6t_log_target,
 479         .checkentry     = ip6t_log_checkentry,
 480         .me             = THIS_MODULE,
 481 };
 482
 483 static int __init init(void)
 484 {
 485         if (ip6t_register_target(&ip6t_log_reg))
 486                 return -EINVAL;
 487         if (nflog)
 488                 nf_log_register(PF_INET6, &ip6t_logfn);
 489
 490         return 0;
 491 }
 492
 493 static void __exit fini(void)
 494 {
 495         if (nflog)
 496                 nf_log_unregister(PF_INET6, &ip6t_logfn);
 497         ip6t_unregister_target(&ip6t_log_reg);
 498 }
 499
 500 module_init(init);
 501 module_exit(fini);