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/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_ipv6/ip6_tables.h>
  25
  26 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
  27 MODULE_DESCRIPTION("IP6 tables LOG target module");
  28 MODULE_LICENSE("GPL");
  29
  30 struct in_device;
  31 #include <net/route.h>
  32 #include <linux/netfilter_ipv6/ip6t_LOG.h>
  33
  34 #if 0
  35 #define DEBUGP printk
  36 #else
  37 #define DEBUGP(format, args...)
  38 #endif
  39
  40 /* Use lock to serialize, so printks don't overlap */
  41 static DEFINE_SPINLOCK(log_lock);
  42
  43 /* One level of recursion won't kill us */
  44 static void dump_packet(const struct nf_loginfo *info,
  45                         const struct sk_buff *skb, unsigned int ip6hoff,
  46                         int recurse)
  47 {
  48         u_int8_t currenthdr;
  49         int fragment;
  50         struct ipv6hdr _ip6h, *ih;
  51         unsigned int ptr;
  52         unsigned int hdrlen = 0;
  53         unsigned int logflags;
  54
  55         if (info->type == NF_LOG_TYPE_LOG)
  56                 logflags = info->u.log.logflags;
  57         else
  58                 logflags = NF_LOG_MASK;
  59
  60         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
  61         if (ih == NULL) {
  62                 printk("TRUNCATED");
  63                 return;
  64         }
  65
  66         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
  67         printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));
  68
  69         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
  70         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
  71                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
  72                (ntohl(*(u_int32_t *)ih) & 0x0ff00000) >> 20,
  73                ih->hop_limit,
  74                (ntohl(*(u_int32_t *)ih) & 0x000fffff));
  75
  76         fragment = 0;
  77         ptr = ip6hoff + sizeof(struct ipv6hdr);
  78         currenthdr = ih->nexthdr;
  79         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
  80                 struct ipv6_opt_hdr _hdr, *hp;
  81
  82                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
  83                 if (hp == NULL) {
  84                         printk("TRUNCATED");
  85                         return;
  86                 }
  87
  88                 /* Max length: 48 "OPT (...) " */
  89                 if (logflags & IP6T_LOG_IPOPT)
  90                         printk("OPT ( ");
  91
  92                 switch (currenthdr) {
  93                 case IPPROTO_FRAGMENT: {
  94                         struct frag_hdr _fhdr, *fh;
  95
  96                         printk("FRAG:");
  97                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
  98                                                 &_fhdr);
  99                         if (fh == NULL) {
 100                                 printk("TRUNCATED ");
 101                                 return;
 102                         }
 103
 104                         /* Max length: 6 "65535 " */
 105                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
 106
 107                         /* Max length: 11 "INCOMPLETE " */
 108                         if (fh->frag_off & htons(0x0001))
 109                                 printk("INCOMPLETE ");
 110
 111                         printk("ID:%08x ", ntohl(fh->identification));
 112
 113                         if (ntohs(fh->frag_off) & 0xFFF8)
 114                                 fragment = 1;
 115
 116                         hdrlen = 8;
 117
 118                         break;
 119                 }
 120                 case IPPROTO_DSTOPTS:
 121                 case IPPROTO_ROUTING:
 122                 case IPPROTO_HOPOPTS:
 123                         if (fragment) {
 124                                 if (logflags & IP6T_LOG_IPOPT)
 125                                         printk(")");
 126                                 return;
 127                         }
 128                         hdrlen = ipv6_optlen(hp);
 129                         break;
 130                 /* Max Length */
 131                 case IPPROTO_AH:
 132                         if (logflags & IP6T_LOG_IPOPT) {
 133                                 struct ip_auth_hdr _ahdr, *ah;
 134
 135                                 /* Max length: 3 "AH " */
 136                                 printk("AH ");
 137
 138                                 if (fragment) {
 139                                         printk(")");
 140                                         return;
 141                                 }
 142
 143                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
 144                                                         &_ahdr);
 145                                 if (ah == NULL) {
 146                                         /*
 147                                          * Max length: 26 "INCOMPLETE [65535
 148                                          *  bytes] )"
 149                                          */
 150                                         printk("INCOMPLETE [%u bytes] )",
 151                                                skb->len - ptr);
 152                                         return;
 153                                 }
 154
 155                                 /* Length: 15 "SPI=0xF1234567 */
 156                                 printk("SPI=0x%x ", ntohl(ah->spi));
 157
 158                         }
 159
 160                         hdrlen = (hp->hdrlen+2)<<2;
 161                         break;
 162                 case IPPROTO_ESP:
 163                         if (logflags & IP6T_LOG_IPOPT) {
 164                                 struct ip_esp_hdr _esph, *eh;
 165
 166                                 /* Max length: 4 "ESP " */
 167                                 printk("ESP ");
 168
 169                                 if (fragment) {
 170                                         printk(")");
 171                                         return;
 172                                 }
 173
 174                                 /*
 175                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
 176                                  */
 177                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
 178                                                         &_esph);
 179                                 if (eh == NULL) {
 180                                         printk("INCOMPLETE [%u bytes] )",
 181                                                skb->len - ptr);
 182                                         return;
 183                                 }
 184
 185                                 /* Length: 16 "SPI=0xF1234567 )" */
 186                                 printk("SPI=0x%x )", ntohl(eh->spi) );
 187
 188                         }
 189                         return;
 190                 default:
 191                         /* Max length: 20 "Unknown Ext Hdr 255" */
 192                         printk("Unknown Ext Hdr %u", currenthdr);
 193                         return;
 194                 }
 195                 if (logflags & IP6T_LOG_IPOPT)
 196                         printk(") ");
 197
 198                 currenthdr = hp->nexthdr;
 199                 ptr += hdrlen;
 200         }
 201
 202         switch (currenthdr) {
 203         case IPPROTO_TCP: {
 204                 struct tcphdr _tcph, *th;
 205
 206                 /* Max length: 10 "PROTO=TCP " */
 207                 printk("PROTO=TCP ");
 208
 209                 if (fragment)
 210                         break;
 211
 212                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 213                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
 214                 if (th == NULL) {
 215                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 216                         return;
 217                 }
 218
 219                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 220                 printk("SPT=%u DPT=%u ",
 221                        ntohs(th->source), ntohs(th->dest));
 222                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
 223                 if (logflags & IP6T_LOG_TCPSEQ)
 224                         printk("SEQ=%u ACK=%u ",
 225                                ntohl(th->seq), ntohl(th->ack_seq));
 226                 /* Max length: 13 "WINDOW=65535 " */
 227                 printk("WINDOW=%u ", ntohs(th->window));
 228                 /* Max length: 9 "RES=0x3C " */
 229                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
 230                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
 231                 if (th->cwr)
 232                         printk("CWR ");
 233                 if (th->ece)
 234                         printk("ECE ");
 235                 if (th->urg)
 236                         printk("URG ");
 237                 if (th->ack)
 238                         printk("ACK ");
 239                 if (th->psh)
 240                         printk("PSH ");
 241                 if (th->rst)
 242                         printk("RST ");
 243                 if (th->syn)
 244                         printk("SYN ");
 245                 if (th->fin)
 246                         printk("FIN ");
 247                 /* Max length: 11 "URGP=65535 " */
 248                 printk("URGP=%u ", ntohs(th->urg_ptr));
 249
 250                 if ((logflags & IP6T_LOG_TCPOPT)
 251                     && th->doff * 4 > sizeof(struct tcphdr)) {
 252                         u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
 253                         unsigned int i;
 254                         unsigned int optsize = th->doff * 4
 255                                                - sizeof(struct tcphdr);
 256
 257                         op = skb_header_pointer(skb,
 258                                                 ptr + sizeof(struct tcphdr),
 259                                                 optsize, _opt);
 260                         if (op == NULL) {
 261                                 printk("OPT (TRUNCATED)");
 262                                 return;
 263                         }
 264
 265                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
 266                         printk("OPT (");
 267                         for (i =0; i < optsize; i++)
 268                                 printk("%02X", op[i]);
 269                         printk(") ");
 270                 }
 271                 break;
 272         }
 273         case IPPROTO_UDP: {
 274                 struct udphdr _udph, *uh;
 275
 276                 /* Max length: 10 "PROTO=UDP " */
 277                 printk("PROTO=UDP ");
 278
 279                 if (fragment)
 280                         break;
 281
 282                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 283                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
 284                 if (uh == NULL) {
 285                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 286                         return;
 287                 }
 288
 289                 /* Max length: 20 "SPT=65535 DPT=65535 " */
 290                 printk("SPT=%u DPT=%u LEN=%u ",
 291                        ntohs(uh->source), ntohs(uh->dest),
 292                        ntohs(uh->len));
 293                 break;
 294         }
 295         case IPPROTO_ICMPV6: {
 296                 struct icmp6hdr _icmp6h, *ic;
 297
 298                 /* Max length: 13 "PROTO=ICMPv6 " */
 299                 printk("PROTO=ICMPv6 ");
 300
 301                 if (fragment)
 302                         break;
 303
 304                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
 305                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
 306                 if (ic == NULL) {
 307                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
 308                         return;
 309                 }
 310
 311                 /* Max length: 18 "TYPE=255 CODE=255 " */
 312                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
 313
 314                 switch (ic->icmp6_type) {
 315                 case ICMPV6_ECHO_REQUEST:
 316                 case ICMPV6_ECHO_REPLY:
 317                         /* Max length: 19 "ID=65535 SEQ=65535 " */
 318                         printk("ID=%u SEQ=%u ",
 319                                 ntohs(ic->icmp6_identifier),
 320                                 ntohs(ic->icmp6_sequence));
 321                         break;
 322                 case ICMPV6_MGM_QUERY:
 323                 case ICMPV6_MGM_REPORT:
 324                 case ICMPV6_MGM_REDUCTION:
 325                         break;
 326
 327                 case ICMPV6_PARAMPROB:
 328                         /* Max length: 17 "POINTER=ffffffff " */
 329                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
 330                         /* Fall through */
 331                 case ICMPV6_DEST_UNREACH:
 332                 case ICMPV6_PKT_TOOBIG:
 333                 case ICMPV6_TIME_EXCEED:
 334                         /* Max length: 3+maxlen */
 335                         if (recurse) {
 336                                 printk("[");
 337                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
 338                                             0);
 339                                 printk("] ");
 340                         }
 341
 342                         /* Max length: 10 "MTU=65535 " */
 343                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
 344                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
 345                 }
 346                 break;
 347         }
 348         /* Max length: 10 "PROTO=255 " */
 349         default:
 350                 printk("PROTO=%u ", currenthdr);
 351         }
 352
 353         /* Max length: 15 "UID=4294967295 " */
 354         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
 355                 read_lock_bh(&skb->sk->sk_callback_lock);
 356                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
 357                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
 358                 read_unlock_bh(&skb->sk->sk_callback_lock);
 359         }
 360 }
 361
 362 static struct nf_loginfo default_loginfo = {
 363         .type   = NF_LOG_TYPE_LOG,
 364         .u = {
 365                 .log = {
 366                         .level    = 0,
 367                         .logflags = NF_LOG_MASK,
 368                 },
 369         },
 370 };
 371
 372 static void
 373 ip6t_log_packet(unsigned int pf,
 374                 unsigned int hooknum,
 375                 const struct sk_buff *skb,
 376                 const struct net_device *in,
 377                 const struct net_device *out,
 378                 const struct nf_loginfo *loginfo,
 379                 const char *prefix)
 380 {
 381         if (!loginfo)
 382                 loginfo = &default_loginfo;
 383
 384         spin_lock_bh(&log_lock);
 385         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
 386                 prefix,
 387                 in ? in->name : "",
 388                 out ? out->name : "");
 389         if (in && !out) {
 390                 unsigned int len;
 391                 /* MAC logging for input chain only. */
 392                 printk("MAC=");
 393                 if (skb->dev && (len = skb->dev->hard_header_len) &&
 394                     skb->mac.raw != skb->nh.raw) {
 395                         unsigned char *p = skb->mac.raw;
 396                         int i;
 397
 398                         if (skb->dev->type == ARPHRD_SIT &&
 399                             (p -= ETH_HLEN) < skb->head)
 400                                 p = NULL;
 401
 402                         if (p != NULL) {
 403                                 for (i = 0; i < len; i++)
 404                                         printk("%02x%s", p[i],
 405                                                i == len - 1 ? "" : ":");
 406                         }
 407                         printk(" ");
 408
 409                         if (skb->dev->type == ARPHRD_SIT) {
 410                                 struct iphdr *iph = (struct iphdr *)skb->mac.raw;
 411                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
 412                                        NIPQUAD(iph->saddr),
 413                                        NIPQUAD(iph->daddr));
 414                         }
 415                 } else
 416                         printk(" ");
 417         }
 418
 419         dump_packet(loginfo, skb, (u8*)skb->nh.ipv6h - skb->data, 1);
 420         printk("\n");
 421         spin_unlock_bh(&log_lock);
 422 }
 423
 424 static unsigned int
 425 ip6t_log_target(struct sk_buff **pskb,
 426                 const struct net_device *in,
 427                 const struct net_device *out,
 428                 unsigned int hooknum,
 429                 const struct xt_target *target,
 430                 const void *targinfo,
 431                 void *userinfo)
 432 {
 433         const struct ip6t_log_info *loginfo = targinfo;
 434         struct nf_loginfo li;
 435
 436         li.type = NF_LOG_TYPE_LOG;
 437         li.u.log.level = loginfo->level;
 438         li.u.log.logflags = loginfo->logflags;
 439
 440         if (loginfo->logflags & IP6T_LOG_NFLOG)
 441                 nf_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
 442                               "%s", loginfo->prefix);
 443         else
 444                 ip6t_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
 445                                 loginfo->prefix);
 446
 447         return IP6T_CONTINUE;
 448 }
 449
 450
 451 static int ip6t_log_checkentry(const char *tablename,
 452                                const void *entry,
 453                                const struct xt_target *target,
 454                                void *targinfo,
 455                                unsigned int targinfosize,
 456                                unsigned int hook_mask)
 457 {
 458         const struct ip6t_log_info *loginfo = targinfo;
 459
 460         if (loginfo->level >= 8) {
 461                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
 462                 return 0;
 463         }
 464         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
 465                 DEBUGP("LOG: prefix term %i\n",
 466                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
 467                 return 0;
 468         }
 469         return 1;
 470 }
 471
 472 static struct ip6t_target ip6t_log_reg = {
 473         .name           = "LOG",
 474         .target         = ip6t_log_target,
 475         .targetsize     = sizeof(struct ip6t_log_info),
 476         .checkentry     = ip6t_log_checkentry,
 477         .me             = THIS_MODULE,
 478 };
 479
 480 static struct nf_logger ip6t_logger = {
 481         .name           = "ip6t_LOG",
 482         .logfn          = &ip6t_log_packet,
 483         .me             = THIS_MODULE,
 484 };
 485
 486 static int __init ip6t_log_init(void)
 487 {
 488         if (ip6t_register_target(&ip6t_log_reg))
 489                 return -EINVAL;
 490         if (nf_log_register(PF_INET6, &ip6t_logger) < 0) {
 491                 printk(KERN_WARNING "ip6t_LOG: not logging via system console "
 492                        "since somebody else already registered for PF_INET6\n");
 493                 /* we cannot make module load fail here, since otherwise
 494                  * ip6tables userspace would abort */
 495         }
 496
 497         return 0;
 498 }
 499
 500 static void __exit ip6t_log_fini(void)
 501 {
 502         nf_log_unregister_logger(&ip6t_logger);
 503         ip6t_unregister_target(&ip6t_log_reg);
 504 }
 505
 506 module_init(ip6t_log_init);
 507 module_exit(ip6t_log_fini);