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   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/if_arp.h>
  17 #include <linux/ip.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/icmpv6.h>
  20 #include <net/udp.h>
  21 #include <net/tcp.h>
  22 #include <net/ipv6.h>
  23 #include <linux/netfilter.h>
  24 #include <linux/netfilter/x_tables.h>
  25 #include <linux/netfilter_ipv6/ip6_tables.h>
  26
  27 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
  28 MODULE_DESCRIPTION("IP6 tables LOG target module");
  29 MODULE_LICENSE("GPL");
  30
  31 struct in_device;
  32 #include <net/route.h>
  33 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  34
  35 #if 0
  36 #define DEBUGP printk
  37 #else
  38 #define DEBUGP(format, args...)
  39 #endif
  40
  41 /* Use lock to serialize, so printks don't overlap */
  42 static DEFINE_SPINLOCK(log_lock);
  43
  44 /* One level of recursion won't kill us */
  45 static void dump_packet(const struct nf_loginfo *info,
  46                         const struct sk_buff *skb, unsigned int ip6hoff,
  47                         int recurse)
  48 {
  49         u_int8_t currenthdr;
  50         int fragment;
  51         struct ipv6hdr _ip6h;
  52         const struct ipv6hdr *ih;
  53         unsigned int ptr;
  54         unsigned int hdrlen = 0;
  55         unsigned int logflags;
  56
  57         if (info->type == NF_LOG_TYPE_LOG)
  58                 logflags = info->u.log.logflags;
  59         else
  60                 logflags = NF_LOG_MASK;
  61
  62         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  63         if (ih == NULL) {
  64                 printk("TRUNCATED");
  65                 return;
  66         }
  67
  68         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  69         printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));
  70
  71         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  72         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  73                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  74                (ntohl(*(__be32 *)ih) & 0x0ff00000) >> 20,
  75                ih->hop_limit,
  76                (ntohl(*(__be32 *)ih) & 0x000fffff));
  77
  78         fragment = 0;
  79         ptr = ip6hoff + sizeof(struct ipv6hdr);
  80         currenthdr = ih->nexthdr;
  81         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  82                 struct ipv6_opt_hdr _hdr;
  83                 const struct ipv6_opt_hdr *hp;
  84
  85                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  86                 if (hp == NULL) {
  87                         printk("TRUNCATED");
  88                         return;
  89                 }
  90
  91                 /* Max length: 48 "OPT (...) " */
  92                 if (logflags & IP6T_LOG_IPOPT)
  93                         printk("OPT ( ");
  94
  95                 switch (currenthdr) {
  96                 case IPPROTO_FRAGMENT: {
  97                         struct frag_hdr _fhdr;
  98                         const struct frag_hdr *fh;
  99
 100                         printk("FRAG:");
 101                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
 102                                                 &_fhdr);
 103                         if (fh == NULL) {
 104                                 printk("TRUNCATED ");
 105                                 return;
 106                         }
 107
 108                         /* Max length: 6 "65535 " */
 109                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
 110
 111                         /* Max length: 11 "INCOMPLETE " */
 112                         if (fh->frag_off & htons(0x0001))
 113                                 printk("INCOMPLETE ");
 114
 115                         printk("ID:%08x ", ntohl(fh->identification));
 116
 117                         if (ntohs(fh->frag_off) & 0xFFF8)
 118                                 fragment = 1;
 119
 120                         hdrlen = 8;
 121
 122                         break;
 123                 }
 124                 case IPPROTO_DSTOPTS:
 125                 case IPPROTO_ROUTING:
 126                 case IPPROTO_HOPOPTS:
 127                         if (fragment) {
 128                                 if (logflags & IP6T_LOG_IPOPT)
 129                                         printk(")");
 130                                 return;
 131                         }
 132                         hdrlen = ipv6_optlen(hp);
 133                         break;
 134                 /* Max Length */
 135                 case IPPROTO_AH:
 136                         if (logflags & IP6T_LOG_IPOPT) {
 137                                 struct ip_auth_hdr _ahdr;
 138                                 const struct ip_auth_hdr *ah;
 139
 140                                 /* Max length: 3 "AH " */
 141                                 printk("AH ");
 142
 143                                 if (fragment) {
 144                                         printk(")");
 145                                         return;
 146                                 }
 147
 148                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 149                                                         &_ahdr);
 150                                 if (ah == NULL) {
 151                                         /*
 152                                          * Max length: 26 "INCOMPLETE [65535
 153                                          *  bytes] )"
 154                                          */
 155                                         printk("INCOMPLETE [%u bytes] )",
 156                                                skb->len - ptr);
 157                                         return;
 158                                 }
 159
 160                                 /* Length: 15 "SPI=0xF1234567 */
 161                                 printk("SPI=0x%x ", ntohl(ah->spi));
 162
 163                         }
 164
 165                         hdrlen = (hp->hdrlen+2)<<2;
 166                         break;
 167                 case IPPROTO_ESP:
 168                         if (logflags & IP6T_LOG_IPOPT) {
 169                                 struct ip_esp_hdr _esph;
 170                                 const struct ip_esp_hdr *eh;
 171
 172                                 /* Max length: 4 "ESP " */
 173                                 printk("ESP ");
 174
 175                                 if (fragment) {
 176                                         printk(")");
 177                                         return;
 178                                 }
 179
 180                                 /*
 181                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 182                                  */
 183                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 184                                                         &_esph);
 185                                 if (eh == NULL) {
 186                                         printk("INCOMPLETE [%u bytes] )",
 187                                                skb->len - ptr);
 188                                         return;
 189                                 }
 190
 191                                 /* Length: 16 "SPI=0xF1234567 )" */
 192                                 printk("SPI=0x%x )", ntohl(eh->spi) );
 193
 194                         }
 195                         return;
 196                 default:
 197                         /* Max length: 20 "Unknown Ext Hdr 255" */
 198                         printk("Unknown Ext Hdr %u", currenthdr);
 199                         return;
 200                 }
 201                 if (logflags & IP6T_LOG_IPOPT)
 202                         printk(") ");
 203
 204                 currenthdr = hp->nexthdr;
 205                 ptr += hdrlen;
 206         }
 207
 208         switch (currenthdr) {
 209         case IPPROTO_TCP: {
 210                 struct tcphdr _tcph;
 211                 const struct tcphdr *th;
 212
 213                 /* Max length: 10 "PROTO=TCP " */
 214                 printk("PROTO=TCP ");
 215
 216                 if (fragment)
 217                         break;
 218
 219                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 220                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
 221                 if (th == NULL) {
 222                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 223                         return;
 224                 }
 225
 226                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 227                 printk("SPT=%u DPT=%u ",
 228                        ntohs(th->source), ntohs(th->dest));
 229                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 230                 if (logflags & IP6T_LOG_TCPSEQ)
 231                         printk("SEQ=%u ACK=%u ",
 232                                ntohl(th->seq), ntohl(th->ack_seq));
 233                 /* Max length: 13 "WINDOW=65535 " */
 234                 printk("WINDOW=%u ", ntohs(th->window));
 235                 /* Max length: 9 "RES=0x3C " */
 236                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
 237                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 238                 if (th->cwr)
 239                         printk("CWR ");
 240                 if (th->ece)
 241                         printk("ECE ");
 242                 if (th->urg)
 243                         printk("URG ");
 244                 if (th->ack)
 245                         printk("ACK ");
 246                 if (th->psh)
 247                         printk("PSH ");
 248                 if (th->rst)
 249                         printk("RST ");
 250                 if (th->syn)
 251                         printk("SYN ");
 252                 if (th->fin)
 253                         printk("FIN ");
 254                 /* Max length: 11 "URGP=65535 " */
 255                 printk("URGP=%u ", ntohs(th->urg_ptr));
 256
 257                 if ((logflags & IP6T_LOG_TCPOPT)
 258                     && th->doff * 4 > sizeof(struct tcphdr)) {
 259                         u_int8_t _opt[60 - sizeof(struct tcphdr)];
 260                         const u_int8_t *op;
 261                         unsigned int i;
 262                         unsigned int optsize = th->doff * 4
 263                                                - sizeof(struct tcphdr);
 264
 265                         op = skb_header_pointer(skb,
 266                                                 ptr + sizeof(struct tcphdr),
 267                                                 optsize, _opt);
 268                         if (op == NULL) {
 269                                 printk("OPT (TRUNCATED)");
 270                                 return;
 271                         }
 272
 273                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
 274                         printk("OPT (");
 275                         for (i =0; i < optsize; i++)
 276                                 printk("%02X", op[i]);
 277                         printk(") ");
 278                 }
 279                 break;
 280         }
 281         case IPPROTO_UDP:
 282         case IPPROTO_UDPLITE: {
 283                 struct udphdr _udph;
 284                 const struct udphdr *uh;
 285
 286                 if (currenthdr == IPPROTO_UDP)
 287                         /* Max length: 10 "PROTO=UDP "     */
 288                         printk("PROTO=UDP " );
 289                 else    /* Max length: 14 "PROTO=UDPLITE " */
 290                         printk("PROTO=UDPLITE ");
 291
 292                 if (fragment)
 293                         break;
 294
 295                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 296                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 297                 if (uh == NULL) {
 298                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 299                         return;
 300                 }
 301
 302                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 303                 printk("SPT=%u DPT=%u LEN=%u ",
 304                        ntohs(uh->source), ntohs(uh->dest),
 305                        ntohs(uh->len));
 306                 break;
 307         }
 308         case IPPROTO_ICMPV6: {
 309                 struct icmp6hdr _icmp6h;
 310                 const struct icmp6hdr *ic;
 311
 312                 /* Max length: 13 "PROTO=ICMPv6 " */
 313                 printk("PROTO=ICMPv6 ");
 314
 315                 if (fragment)
 316                         break;
 317
 318                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 319                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 320                 if (ic == NULL) {
 321                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 322                         return;
 323                 }
 324
 325                 /* Max length: 18 "TYPE=255 CODE=255 " */
 326                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 327
 328                 switch (ic->icmp6_type) {
 329                 case ICMPV6_ECHO_REQUEST:
 330                 case ICMPV6_ECHO_REPLY:
 331                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 332                         printk("ID=%u SEQ=%u ",
 333                                 ntohs(ic->icmp6_identifier),
 334                                 ntohs(ic->icmp6_sequence));
 335                         break;
 336                 case ICMPV6_MGM_QUERY:
 337                 case ICMPV6_MGM_REPORT:
 338                 case ICMPV6_MGM_REDUCTION:
 339                         break;
 340
 341                 case ICMPV6_PARAMPROB:
 342                         /* Max length: 17 "POINTER=ffffffff " */
 343                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
 344                         /* Fall through */
 345                 case ICMPV6_DEST_UNREACH:
 346                 case ICMPV6_PKT_TOOBIG:
 347                 case ICMPV6_TIME_EXCEED:
 348                         /* Max length: 3+maxlen */
 349                         if (recurse) {
 350                                 printk("[");
 351                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
 352                                             0);
 353                                 printk("] ");
 354                         }
 355
 356                         /* Max length: 10 "MTU=65535 " */
 357                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 358                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 359                 }
 360                 break;
 361         }
 362         /* Max length: 10 "PROTO=255 " */
 363         default:
 364                 printk("PROTO=%u ", currenthdr);
 365         }
 366
 367         /* Max length: 15 "UID=4294967295 " */
 368         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
 369                 read_lock_bh(&skb->sk->sk_callback_lock);
 370                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
 371                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
 372                 read_unlock_bh(&skb->sk->sk_callback_lock);
 373         }
 374 }
 375
 376 static struct nf_loginfo default_loginfo = {
 377         .type   = NF_LOG_TYPE_LOG,
 378         .u = {
 379                 .log = {
 380                         .level    = 0,
 381                         .logflags = NF_LOG_MASK,
 382                 },
 383         },
 384 };
 385
 386 static void
 387 ip6t_log_packet(unsigned int pf,
 388                 unsigned int hooknum,
 389                 const struct sk_buff *skb,
 390                 const struct net_device *in,
 391                 const struct net_device *out,
 392                 const struct nf_loginfo *loginfo,
 393                 const char *prefix)
 394 {
 395         if (!loginfo)
 396                 loginfo = &default_loginfo;
 397
 398         spin_lock_bh(&log_lock);
 399         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
 400                 prefix,
 401                 in ? in->name : "",
 402                 out ? out->name : "");
 403         if (in && !out) {
 404                 unsigned int len;
 405                 /* MAC logging for input chain only. */
 406                 printk("MAC=");
 407                 if (skb->dev && (len = skb->dev->hard_header_len) &&
 408                     skb->mac_header != skb->network_header) {
 409                         const unsigned char *p = skb_mac_header(skb);
 410                         int i;
 411
 412                         if (skb->dev->type == ARPHRD_SIT &&
 413                             (p -= ETH_HLEN) < skb->head)
 414                                 p = NULL;
 415
 416                         if (p != NULL) {
 417                                 for (i = 0; i < len; i++)
 418                                         printk("%02x%s", p[i],
 419                                                i == len - 1 ? "" : ":");
 420                         }
 421                         printk(" ");
 422
 423                         if (skb->dev->type == ARPHRD_SIT) {
 424                                 const struct iphdr *iph =
 425                                         (struct iphdr *)skb_mac_header(skb);
 426                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
 427                                        NIPQUAD(iph->saddr),
 428                                        NIPQUAD(iph->daddr));
 429                         }
 430                 } else
 431                         printk(" ");
 432         }
 433
 434         dump_packet(loginfo, skb, skb_network_offset(skb), 1);
 435         printk("\n");
 436         spin_unlock_bh(&log_lock);
 437 }
 438
 439 static unsigned int
 440 ip6t_log_target(struct sk_buff **pskb,
 441                 const struct net_device *in,
 442                 const struct net_device *out,
 443                 unsigned int hooknum,
 444                 const struct xt_target *target,
 445                 const void *targinfo)
 446 {
 447         const struct ip6t_log_info *loginfo = targinfo;
 448         struct nf_loginfo li;
 449
 450         li.type = NF_LOG_TYPE_LOG;
 451         li.u.log.level = loginfo->level;
 452         li.u.log.logflags = loginfo->logflags;
 453
 454         ip6t_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
 455                         loginfo->prefix);
 456         return XT_CONTINUE;
 457 }
 458
 459
 460 static bool ip6t_log_checkentry(const char *tablename,
 461                                 const void *entry,
 462                                 const struct xt_target *target,
 463                                 void *targinfo,
 464                                 unsigned int hook_mask)
 465 {
 466         const struct ip6t_log_info *loginfo = targinfo;
 467
 468         if (loginfo->level >= 8) {
 469                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 470                 return false;
 471         }
 472         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 473                 DEBUGP("LOG: prefix term %i\n",
 474                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
 475                 return false;
 476         }
 477         return true;
 478 }
 479
 480 static struct xt_target ip6t_log_reg __read_mostly = {
 481         .name           = "LOG",
 482         .family         = AF_INET6,
 483         .target         = ip6t_log_target,
 484         .targetsize     = sizeof(struct ip6t_log_info),
 485         .checkentry     = ip6t_log_checkentry,
 486         .me             = THIS_MODULE,
 487 };
 488
 489 static struct nf_logger ip6t_logger = {
 490         .name           = "ip6t_LOG",
 491         .logfn          = &ip6t_log_packet,
 492         .me             = THIS_MODULE,
 493 };
 494
 495 static int __init ip6t_log_init(void)
 496 {
 497         int ret;
 498
 499         ret = xt_register_target(&ip6t_log_reg);
 500         if (ret < 0)
 501                 return ret;
 502         ret = nf_log_register(PF_INET6, &ip6t_logger);
 503         if (ret < 0 && ret != -EEXIST)
 504                 xt_unregister_target(&ip6t_log_reg);
 505         return ret;
 506 }
 507
 508 static void __exit ip6t_log_fini(void)
 509 {
 510         nf_log_unregister(&ip6t_logger);
 511         xt_unregister_target(&ip6t_log_reg);
 512 }
 513
 514 module_init(ip6t_log_init);
 515 module_exit(ip6t_log_fini);