SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/netfilter/nfnetlink_log.c

   1 /*
   2  * This is a module which is used for logging packets to userspace via
   3  * nfetlink.
   4  *
   5  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6  *
   7  * Based on the old ipv4-only ipt_ULOG.c:
   8  * (C) 2000-2004 by Harald Welte <laforge@netfilter.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * 2006-01-26 Harald Welte <laforge@netfilter.org>
  15  *      - Add optional local and global sequence number to detect lost
  16  *        events from userspace
  17  *
  18  */
  19 #include <linux/module.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/init.h>
  22 #include <linux/ip.h>
  23 #include <linux/ipv6.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/netfilter.h>
  26 #include <linux/netlink.h>
  27 #include <linux/netfilter/nfnetlink.h>
  28 #include <linux/netfilter/nfnetlink_log.h>
  29 #include <linux/spinlock.h>
  30 #include <linux/sysctl.h>
  31 #include <linux/proc_fs.h>
  32 #include <linux/security.h>
  33 #include <linux/list.h>
  34 #include <linux/jhash.h>
  35 #include <linux/random.h>
  36 #include <net/sock.h>
  37
  38 #include <asm/atomic.h>
  39
  40 #ifdef CONFIG_BRIDGE_NETFILTER
  41 #include "../bridge/br_private.h"
  42 #endif
  43
  44 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  45 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  46 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  47
  48 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  49                                      printk(x, ## args); } while (0);
  50
  51 #if 0
  52 #define UDEBUG(x, args ...)     printk(KERN_DEBUG "%s(%d):%s(): " x,       \
  53                                         __FILE__, __LINE__, __FUNCTION__,  \
  54                                         ## args)
  55 #else
  56 #define UDEBUG(x, ...)
  57 #endif
  58
  59 struct nfulnl_instance {
  60         struct hlist_node hlist;        /* global list of instances */
  61         spinlock_t lock;
  62         atomic_t use;                   /* use count */
  63
  64         unsigned int qlen;              /* number of nlmsgs in skb */
  65         struct sk_buff *skb;            /* pre-allocatd skb */
  66         struct nlmsghdr *lastnlh;       /* netlink header of last msg in skb */
  67         struct timer_list timer;
  68         int peer_pid;                   /* PID of the peer process */
  69
  70         /* configurable parameters */
  71         unsigned int flushtimeout;      /* timeout until queue flush */
  72         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  73         unsigned int qthreshold;        /* threshold of the queue */
  74         u_int32_t copy_range;
  75         u_int32_t seq;                  /* instance-local sequential counter */
  76         u_int16_t group_num;            /* number of this queue */
  77         u_int16_t flags;
  78         u_int8_t copy_mode;
  79 };
  80
  81 static DEFINE_RWLOCK(instances_lock);
  82 static atomic_t global_seq;
  83
  84 #define INSTANCE_BUCKETS        16
  85 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  86 static unsigned int hash_init;
  87
  88 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  89 {
  90         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  91 }
  92
  93 static struct nfulnl_instance *
  94 __instance_lookup(u_int16_t group_num)
  95 {
  96         struct hlist_head *head;
  97         struct hlist_node *pos;
  98         struct nfulnl_instance *inst;
  99
 100         UDEBUG("entering (group_num=%u)\n", group_num);
 101
 102         head = &instance_table[instance_hashfn(group_num)];
 103         hlist_for_each_entry(inst, pos, head, hlist) {
 104                 if (inst->group_num == group_num)
 105                         return inst;
 106         }
 107         return NULL;
 108 }
 109
 110 static inline void
 111 instance_get(struct nfulnl_instance *inst)
 112 {
 113         atomic_inc(&inst->use);
 114 }
 115
 116 static struct nfulnl_instance *
 117 instance_lookup_get(u_int16_t group_num)
 118 {
 119         struct nfulnl_instance *inst;
 120
 121         read_lock_bh(&instances_lock);
 122         inst = __instance_lookup(group_num);
 123         if (inst)
 124                 instance_get(inst);
 125         read_unlock_bh(&instances_lock);
 126
 127         return inst;
 128 }
 129
 130 static void
 131 instance_put(struct nfulnl_instance *inst)
 132 {
 133         if (inst && atomic_dec_and_test(&inst->use)) {
 134                 UDEBUG("kfree(inst=%p)\n", inst);
 135                 kfree(inst);
 136         }
 137 }
 138
 139 static void nfulnl_timer(unsigned long data);
 140
 141 static struct nfulnl_instance *
 142 instance_create(u_int16_t group_num, int pid)
 143 {
 144         struct nfulnl_instance *inst;
 145
 146         UDEBUG("entering (group_num=%u, pid=%d)\n", group_num,
 147                 pid);
 148
 149         write_lock_bh(&instances_lock);
 150         if (__instance_lookup(group_num)) {
 151                 inst = NULL;
 152                 UDEBUG("aborting, instance already exists\n");
 153                 goto out_unlock;
 154         }
 155
 156         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 157         if (!inst)
 158                 goto out_unlock;
 159
 160         INIT_HLIST_NODE(&inst->hlist);
 161         spin_lock_init(&inst->lock);
 162         /* needs to be two, since we _put() after creation */
 163         atomic_set(&inst->use, 2);
 164
 165         init_timer(&inst->timer);
 166         inst->timer.function = nfulnl_timer;
 167         inst->timer.data = (unsigned long)inst;
 168         /* don't start timer yet. (re)start it  with every packet */
 169
 170         inst->peer_pid = pid;
 171         inst->group_num = group_num;
 172
 173         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 174         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 175         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 176         inst->copy_mode         = NFULNL_COPY_PACKET;
 177         inst->copy_range        = 0xffff;
 178
 179         if (!try_module_get(THIS_MODULE))
 180                 goto out_free;
 181
 182         hlist_add_head(&inst->hlist,
 183                        &instance_table[instance_hashfn(group_num)]);
 184
 185         UDEBUG("newly added node: %p, next=%p\n", &inst->hlist,
 186                 inst->hlist.next);
 187
 188         write_unlock_bh(&instances_lock);
 189
 190         return inst;
 191
 192 out_free:
 193         instance_put(inst);
 194 out_unlock:
 195         write_unlock_bh(&instances_lock);
 196         return NULL;
 197 }
 198
 199 static int __nfulnl_send(struct nfulnl_instance *inst);
 200
 201 static void
 202 _instance_destroy2(struct nfulnl_instance *inst, int lock)
 203 {
 204         /* first pull it out of the global list */
 205         if (lock)
 206                 write_lock_bh(&instances_lock);
 207
 208         UDEBUG("removing instance %p (queuenum=%u) from hash\n",
 209                 inst, inst->group_num);
 210
 211         hlist_del(&inst->hlist);
 212
 213         if (lock)
 214                 write_unlock_bh(&instances_lock);
 215
 216         /* then flush all pending packets from skb */
 217
 218         spin_lock_bh(&inst->lock);
 219         if (inst->skb) {
 220                 if (inst->qlen)
 221                         __nfulnl_send(inst);
 222                 if (inst->skb) {
 223                         kfree_skb(inst->skb);
 224                         inst->skb = NULL;
 225                 }
 226         }
 227         spin_unlock_bh(&inst->lock);
 228
 229         /* and finally put the refcount */
 230         instance_put(inst);
 231
 232         module_put(THIS_MODULE);
 233 }
 234
 235 static inline void
 236 __instance_destroy(struct nfulnl_instance *inst)
 237 {
 238         _instance_destroy2(inst, 0);
 239 }
 240
 241 static inline void
 242 instance_destroy(struct nfulnl_instance *inst)
 243 {
 244         _instance_destroy2(inst, 1);
 245 }
 246
 247 static int
 248 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 249                   unsigned int range)
 250 {
 251         int status = 0;
 252
 253         spin_lock_bh(&inst->lock);
 254
 255         switch (mode) {
 256         case NFULNL_COPY_NONE:
 257         case NFULNL_COPY_META:
 258                 inst->copy_mode = mode;
 259                 inst->copy_range = 0;
 260                 break;
 261
 262         case NFULNL_COPY_PACKET:
 263                 inst->copy_mode = mode;
 264                 /* we're using struct nfattr which has 16bit nfa_len */
 265                 if (range > 0xffff)
 266                         inst->copy_range = 0xffff;
 267                 else
 268                         inst->copy_range = range;
 269                 break;
 270
 271         default:
 272                 status = -EINVAL;
 273                 break;
 274         }
 275
 276         spin_unlock_bh(&inst->lock);
 277
 278         return status;
 279 }
 280
 281 static int
 282 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 283 {
 284         int status;
 285
 286         spin_lock_bh(&inst->lock);
 287         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 288                 status = -ERANGE;
 289         else if (nlbufsiz > 131072)
 290                 status = -ERANGE;
 291         else {
 292                 inst->nlbufsiz = nlbufsiz;
 293                 status = 0;
 294         }
 295         spin_unlock_bh(&inst->lock);
 296
 297         return status;
 298 }
 299
 300 static int
 301 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 302 {
 303         spin_lock_bh(&inst->lock);
 304         inst->flushtimeout = timeout;
 305         spin_unlock_bh(&inst->lock);
 306
 307         return 0;
 308 }
 309
 310 static int
 311 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 312 {
 313         spin_lock_bh(&inst->lock);
 314         inst->qthreshold = qthresh;
 315         spin_unlock_bh(&inst->lock);
 316
 317         return 0;
 318 }
 319
 320 static int
 321 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 322 {
 323         spin_lock_bh(&inst->lock);
 324         inst->flags = flags;
 325         spin_unlock_bh(&inst->lock);
 326
 327         return 0;
 328 }
 329
 330 static struct sk_buff *nfulnl_alloc_skb(unsigned int inst_size,
 331                                         unsigned int pkt_size)
 332 {
 333         struct sk_buff *skb;
 334         unsigned int n;
 335
 336         UDEBUG("entered (%u, %u)\n", inst_size, pkt_size);
 337
 338         /* alloc skb which should be big enough for a whole multipart
 339          * message.  WARNING: has to be <= 128k due to slab restrictions */
 340
 341         n = max(inst_size, pkt_size);
 342         skb = alloc_skb(n, GFP_ATOMIC);
 343         if (!skb) {
 344                 PRINTR("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 345                         inst_size);
 346
 347                 if (n > pkt_size) {
 348                         /* try to allocate only as much as we need for current
 349                          * packet */
 350
 351                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 352                         if (!skb)
 353                                 PRINTR("nfnetlink_log: can't even alloc %u "
 354                                        "bytes\n", pkt_size);
 355                 }
 356         }
 357
 358         return skb;
 359 }
 360
 361 static int
 362 __nfulnl_send(struct nfulnl_instance *inst)
 363 {
 364         int status;
 365
 366         if (timer_pending(&inst->timer))
 367                 del_timer(&inst->timer);
 368
 369         if (!inst->skb)
 370                 return 0;
 371
 372         if (inst->qlen > 1)
 373                 inst->lastnlh->nlmsg_type = NLMSG_DONE;
 374
 375         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
 376         if (status < 0) {
 377                 UDEBUG("netlink_unicast() failed\n");
 378                 /* FIXME: statistics */
 379         }
 380
 381         inst->qlen = 0;
 382         inst->skb = NULL;
 383         inst->lastnlh = NULL;
 384
 385         return status;
 386 }
 387
 388 static void nfulnl_timer(unsigned long data)
 389 {
 390         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 391
 392         UDEBUG("timer function called, flushing buffer\n");
 393
 394         spin_lock_bh(&inst->lock);
 395         __nfulnl_send(inst);
 396         instance_put(inst);
 397         spin_unlock_bh(&inst->lock);
 398 }
 399
 400 /* This is an inline function, we don't really care about a long
 401  * list of arguments */
 402 static inline int
 403 __build_packet_message(struct nfulnl_instance *inst,
 404                         const struct sk_buff *skb,
 405                         unsigned int data_len,
 406                         unsigned int pf,
 407                         unsigned int hooknum,
 408                         const struct net_device *indev,
 409                         const struct net_device *outdev,
 410                         const struct nf_loginfo *li,
 411                         const char *prefix, unsigned int plen)
 412 {
 413         unsigned char *old_tail;
 414         struct nfulnl_msg_packet_hdr pmsg;
 415         struct nlmsghdr *nlh;
 416         struct nfgenmsg *nfmsg;
 417         __be32 tmp_uint;
 418
 419         UDEBUG("entered\n");
 420
 421         old_tail = inst->skb->tail;
 422         nlh = NLMSG_PUT(inst->skb, 0, 0,
 423                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 424                         sizeof(struct nfgenmsg));
 425         nfmsg = NLMSG_DATA(nlh);
 426         nfmsg->nfgen_family = pf;
 427         nfmsg->version = NFNETLINK_V0;
 428         nfmsg->res_id = htons(inst->group_num);
 429
 430         pmsg.hw_protocol        = skb->protocol;
 431         pmsg.hook               = hooknum;
 432
 433         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 434
 435         if (prefix)
 436                 NFA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
 437
 438         if (indev) {
 439                 tmp_uint = htonl(indev->ifindex);
 440 #ifndef CONFIG_BRIDGE_NETFILTER
 441                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
 442                         &tmp_uint);
 443 #else
 444                 if (pf == PF_BRIDGE) {
 445                         /* Case 1: outdev is physical input device, we need to
 446                          * look for bridge group (when called from
 447                          * netfilter_bridge) */
 448                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 449                                 sizeof(tmp_uint), &tmp_uint);
 450                         /* this is the bridge group "brX" */
 451                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
 452                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 453                                 sizeof(tmp_uint), &tmp_uint);
 454                 } else {
 455                         /* Case 2: indev is bridge group, we need to look for
 456                          * physical device (when called from ipv4) */
 457                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 458                                 sizeof(tmp_uint), &tmp_uint);
 459                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
 460                                 tmp_uint =
 461                                     htonl(skb->nf_bridge->physindev->ifindex);
 462                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 463                                         sizeof(tmp_uint), &tmp_uint);
 464                         }
 465                 }
 466 #endif
 467         }
 468
 469         if (outdev) {
 470                 tmp_uint = htonl(outdev->ifindex);
 471 #ifndef CONFIG_BRIDGE_NETFILTER
 472                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 473                         &tmp_uint);
 474 #else
 475                 if (pf == PF_BRIDGE) {
 476                         /* Case 1: outdev is physical output device, we need to
 477                          * look for bridge group (when called from
 478                          * netfilter_bridge) */
 479                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 480                                 sizeof(tmp_uint), &tmp_uint);
 481                         /* this is the bridge group "brX" */
 482                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
 483                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 484                                 sizeof(tmp_uint), &tmp_uint);
 485                 } else {
 486                         /* Case 2: indev is a bridge group, we need to look
 487                          * for physical device (when called from ipv4) */
 488                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 489                                 sizeof(tmp_uint), &tmp_uint);
 490                         if (skb->nf_bridge) {
 491                                 tmp_uint =
 492                                     htonl(skb->nf_bridge->physoutdev->ifindex);
 493                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 494                                         sizeof(tmp_uint), &tmp_uint);
 495                         }
 496                 }
 497 #endif
 498         }
 499
 500         if (skb->mark) {
 501                 tmp_uint = htonl(skb->mark);
 502                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
 503         }
 504
 505         if (indev && skb->dev && skb->dev->hard_header_parse) {
 506                 struct nfulnl_msg_packet_hw phw;
 507                 int len = skb->dev->hard_header_parse((struct sk_buff *)skb,
 508                                                     phw.hw_addr);
 509                 phw.hw_addrlen = htons(len);
 510                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 511         }
 512
 513         if (skb->tstamp.off_sec) {
 514                 struct nfulnl_msg_packet_timestamp ts;
 515
 516                 ts.sec = cpu_to_be64(skb->tstamp.off_sec);
 517                 ts.usec = cpu_to_be64(skb->tstamp.off_usec);
 518
 519                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 520         }
 521
 522         /* UID */
 523         if (skb->sk) {
 524                 read_lock_bh(&skb->sk->sk_callback_lock);
 525                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 526                         __be32 uid = htonl(skb->sk->sk_socket->file->f_uid);
 527                         /* need to unlock here since NFA_PUT may goto */
 528                         read_unlock_bh(&skb->sk->sk_callback_lock);
 529                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
 530                 } else
 531                         read_unlock_bh(&skb->sk->sk_callback_lock);
 532         }
 533
 534         /* local sequence number */
 535         if (inst->flags & NFULNL_CFG_F_SEQ) {
 536                 tmp_uint = htonl(inst->seq++);
 537                 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
 538         }
 539         /* global sequence number */
 540         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
 541                 tmp_uint = htonl(atomic_inc_return(&global_seq));
 542                 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
 543         }
 544
 545         if (data_len) {
 546                 struct nfattr *nfa;
 547                 int size = NFA_LENGTH(data_len);
 548
 549                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
 550                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 551                         goto nlmsg_failure;
 552                 }
 553
 554                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
 555                 nfa->nfa_type = NFULA_PAYLOAD;
 556                 nfa->nfa_len = size;
 557
 558                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
 559                         BUG();
 560         }
 561
 562         nlh->nlmsg_len = inst->skb->tail - old_tail;
 563         return 0;
 564
 565 nlmsg_failure:
 566         UDEBUG("nlmsg_failure\n");
 567 nfattr_failure:
 568         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 569         return -1;
 570 }
 571
 572 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 573
 574 static struct nf_loginfo default_loginfo = {
 575         .type =         NF_LOG_TYPE_ULOG,
 576         .u = {
 577                 .ulog = {
 578                         .copy_len       = 0xffff,
 579                         .group          = 0,
 580                         .qthreshold     = 1,
 581                 },
 582         },
 583 };
 584
 585 /* log handler for internal netfilter logging api */
 586 static void
 587 nfulnl_log_packet(unsigned int pf,
 588                   unsigned int hooknum,
 589                   const struct sk_buff *skb,
 590                   const struct net_device *in,
 591                   const struct net_device *out,
 592                   const struct nf_loginfo *li_user,
 593                   const char *prefix)
 594 {
 595         unsigned int size, data_len;
 596         struct nfulnl_instance *inst;
 597         const struct nf_loginfo *li;
 598         unsigned int qthreshold;
 599         unsigned int nlbufsiz;
 600         unsigned int plen;
 601
 602         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 603                 li = li_user;
 604         else
 605                 li = &default_loginfo;
 606
 607         inst = instance_lookup_get(li->u.ulog.group);
 608         if (!inst)
 609                 inst = instance_lookup_get(0);
 610         if (!inst) {
 611                 PRINTR("nfnetlink_log: trying to log packet, "
 612                         "but no instance for group %u\n", li->u.ulog.group);
 613                 return;
 614         }
 615
 616         plen = 0;
 617         if (prefix)
 618                 plen = strlen(prefix);
 619
 620         /* all macros expand to constant values at compile time */
 621         /* FIXME: do we want to make the size calculation conditional based on
 622          * what is actually present?  way more branches and checks, but more
 623          * memory efficient... */
 624         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 625                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
 626                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 627                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 628 #ifdef CONFIG_BRIDGE_NETFILTER
 629                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 630                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 631 #endif
 632                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
 633                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
 634                 + NFA_SPACE(plen)               /* prefix */
 635                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
 636                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
 637
 638         UDEBUG("initial size=%u\n", size);
 639
 640         spin_lock_bh(&inst->lock);
 641
 642         if (inst->flags & NFULNL_CFG_F_SEQ)
 643                 size += NFA_SPACE(sizeof(u_int32_t));
 644         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 645                 size += NFA_SPACE(sizeof(u_int32_t));
 646
 647         qthreshold = inst->qthreshold;
 648         /* per-rule qthreshold overrides per-instance */
 649         if (qthreshold > li->u.ulog.qthreshold)
 650                 qthreshold = li->u.ulog.qthreshold;
 651
 652         switch (inst->copy_mode) {
 653         case NFULNL_COPY_META:
 654         case NFULNL_COPY_NONE:
 655                 data_len = 0;
 656                 break;
 657
 658         case NFULNL_COPY_PACKET:
 659                 if (inst->copy_range == 0
 660                     || inst->copy_range > skb->len)
 661                         data_len = skb->len;
 662                 else
 663                         data_len = inst->copy_range;
 664
 665                 size += NFA_SPACE(data_len);
 666                 UDEBUG("copy_packet, therefore size now %u\n", size);
 667                 break;
 668
 669         default:
 670                 spin_unlock_bh(&inst->lock);
 671                 instance_put(inst);
 672                 return;
 673         }
 674
 675         if (size > inst->nlbufsiz)
 676                 nlbufsiz = size;
 677         else
 678                 nlbufsiz = inst->nlbufsiz;
 679
 680         if (!inst->skb) {
 681                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 682                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 683                                 inst->nlbufsiz, size);
 684                         goto alloc_failure;
 685                 }
 686         } else if (inst->qlen >= qthreshold ||
 687                    size > skb_tailroom(inst->skb)) {
 688                 /* either the queue len is too high or we don't have
 689                  * enough room in the skb left. flush to userspace. */
 690                 UDEBUG("flushing old skb\n");
 691
 692                 __nfulnl_send(inst);
 693
 694                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 695                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 696                                 inst->nlbufsiz, size);
 697                         goto alloc_failure;
 698                 }
 699         }
 700
 701         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
 702         inst->qlen++;
 703
 704         __build_packet_message(inst, skb, data_len, pf,
 705                                 hooknum, in, out, li, prefix, plen);
 706
 707         /* timer_pending always called within inst->lock, so there
 708          * is no chance of a race here */
 709         if (!timer_pending(&inst->timer)) {
 710                 instance_get(inst);
 711                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 712                 add_timer(&inst->timer);
 713         }
 714         spin_unlock_bh(&inst->lock);
 715
 716         return;
 717
 718 alloc_failure:
 719         spin_unlock_bh(&inst->lock);
 720         instance_put(inst);
 721         UDEBUG("error allocating skb\n");
 722         /* FIXME: statistics */
 723 }
 724
 725 static int
 726 nfulnl_rcv_nl_event(struct notifier_block *this,
 727                    unsigned long event, void *ptr)
 728 {
 729         struct netlink_notify *n = ptr;
 730
 731         if (event == NETLINK_URELEASE &&
 732             n->protocol == NETLINK_NETFILTER && n->pid) {
 733                 int i;
 734
 735                 /* destroy all instances for this pid */
 736                 write_lock_bh(&instances_lock);
 737                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 738                         struct hlist_node *tmp, *t2;
 739                         struct nfulnl_instance *inst;
 740                         struct hlist_head *head = &instance_table[i];
 741
 742                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 743                                 UDEBUG("node = %p\n", inst);
 744                                 if (n->pid == inst->peer_pid)
 745                                         __instance_destroy(inst);
 746                         }
 747                 }
 748                 write_unlock_bh(&instances_lock);
 749         }
 750         return NOTIFY_DONE;
 751 }
 752
 753 static struct notifier_block nfulnl_rtnl_notifier = {
 754         .notifier_call  = nfulnl_rcv_nl_event,
 755 };
 756
 757 static int
 758 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 759                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 760 {
 761         return -ENOTSUPP;
 762 }
 763
 764 static struct nf_logger nfulnl_logger = {
 765         .name   = "nfnetlink_log",
 766         .logfn  = &nfulnl_log_packet,
 767         .me     = THIS_MODULE,
 768 };
 769
 770 static const int nfula_min[NFULA_MAX] = {
 771         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
 772         [NFULA_MARK-1]          = sizeof(u_int32_t),
 773         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
 774         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
 775         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
 776         [NFULA_IFINDEX_PHYSINDEV-1]     = sizeof(u_int32_t),
 777         [NFULA_IFINDEX_PHYSOUTDEV-1]    = sizeof(u_int32_t),
 778         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
 779         [NFULA_PAYLOAD-1]       = 0,
 780         [NFULA_PREFIX-1]        = 0,
 781         [NFULA_UID-1]           = sizeof(u_int32_t),
 782         [NFULA_SEQ-1]           = sizeof(u_int32_t),
 783         [NFULA_SEQ_GLOBAL-1]    = sizeof(u_int32_t),
 784 };
 785
 786 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 787         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
 788         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
 789         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
 790         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
 791         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
 792         [NFULA_CFG_FLAGS-1]     = sizeof(u_int16_t),
 793 };
 794
 795 static int
 796 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 797                    struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
 798 {
 799         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 800         u_int16_t group_num = ntohs(nfmsg->res_id);
 801         struct nfulnl_instance *inst;
 802         int ret = 0;
 803
 804         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 805
 806         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
 807                 UDEBUG("bad attribute size\n");
 808                 return -EINVAL;
 809         }
 810
 811         inst = instance_lookup_get(group_num);
 812         if (nfula[NFULA_CFG_CMD-1]) {
 813                 u_int8_t pf = nfmsg->nfgen_family;
 814                 struct nfulnl_msg_config_cmd *cmd;
 815                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
 816                 UDEBUG("found CFG_CMD for\n");
 817
 818                 switch (cmd->command) {
 819                 case NFULNL_CFG_CMD_BIND:
 820                         if (inst) {
 821                                 ret = -EBUSY;
 822                                 goto out_put;
 823                         }
 824
 825                         inst = instance_create(group_num,
 826                                                NETLINK_CB(skb).pid);
 827                         if (!inst) {
 828                                 ret = -EINVAL;
 829                                 goto out_put;
 830                         }
 831                         break;
 832                 case NFULNL_CFG_CMD_UNBIND:
 833                         if (!inst) {
 834                                 ret = -ENODEV;
 835                                 goto out_put;
 836                         }
 837
 838                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
 839                                 ret = -EPERM;
 840                                 goto out_put;
 841                         }
 842
 843                         instance_destroy(inst);
 844                         break;
 845                 case NFULNL_CFG_CMD_PF_BIND:
 846                         UDEBUG("registering log handler for pf=%u\n", pf);
 847                         ret = nf_log_register(pf, &nfulnl_logger);
 848                         break;
 849                 case NFULNL_CFG_CMD_PF_UNBIND:
 850                         UDEBUG("unregistering log handler for pf=%u\n", pf);
 851                         /* This is a bug and a feature.  We cannot unregister
 852                          * other handlers, like nfnetlink_inst can */
 853                         nf_log_unregister_pf(pf);
 854                         break;
 855                 default:
 856                         ret = -EINVAL;
 857                         break;
 858                 }
 859         } else {
 860                 if (!inst) {
 861                         UDEBUG("no config command, and no instance for "
 862                                 "group=%u pid=%u =>ENOENT\n",
 863                                 group_num, NETLINK_CB(skb).pid);
 864                         ret = -ENOENT;
 865                         goto out_put;
 866                 }
 867
 868                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
 869                         UDEBUG("no config command, and wrong pid\n");
 870                         ret = -EPERM;
 871                         goto out_put;
 872                 }
 873         }
 874
 875         if (nfula[NFULA_CFG_MODE-1]) {
 876                 struct nfulnl_msg_config_mode *params;
 877                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
 878
 879                 nfulnl_set_mode(inst, params->copy_mode,
 880                                 ntohl(params->copy_range));
 881         }
 882
 883         if (nfula[NFULA_CFG_TIMEOUT-1]) {
 884                 __be32 timeout =
 885                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
 886
 887                 nfulnl_set_timeout(inst, ntohl(timeout));
 888         }
 889
 890         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
 891                 __be32 nlbufsiz =
 892                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
 893
 894                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 895         }
 896
 897         if (nfula[NFULA_CFG_QTHRESH-1]) {
 898                 __be32 qthresh =
 899                         *(__be32 *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
 900
 901                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 902         }
 903
 904         if (nfula[NFULA_CFG_FLAGS-1]) {
 905                 __be16 flags =
 906                         *(__be16 *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
 907                 nfulnl_set_flags(inst, ntohs(flags));
 908         }
 909
 910 out_put:
 911         instance_put(inst);
 912         return ret;
 913 }
 914
 915 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 916         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 917                                     .attr_count = NFULA_MAX, },
 918         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 919                                     .attr_count = NFULA_CFG_MAX, },
 920 };
 921
 922 static struct nfnetlink_subsystem nfulnl_subsys = {
 923         .name           = "log",
 924         .subsys_id      = NFNL_SUBSYS_ULOG,
 925         .cb_count       = NFULNL_MSG_MAX,
 926         .cb             = nfulnl_cb,
 927 };
 928
 929 #ifdef CONFIG_PROC_FS
 930 struct iter_state {
 931         unsigned int bucket;
 932 };
 933
 934 static struct hlist_node *get_first(struct seq_file *seq)
 935 {
 936         struct iter_state *st = seq->private;
 937
 938         if (!st)
 939                 return NULL;
 940
 941         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 942                 if (!hlist_empty(&instance_table[st->bucket]))
 943                         return instance_table[st->bucket].first;
 944         }
 945         return NULL;
 946 }
 947
 948 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
 949 {
 950         struct iter_state *st = seq->private;
 951
 952         h = h->next;
 953         while (!h) {
 954                 if (++st->bucket >= INSTANCE_BUCKETS)
 955                         return NULL;
 956
 957                 h = instance_table[st->bucket].first;
 958         }
 959         return h;
 960 }
 961
 962 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
 963 {
 964         struct hlist_node *head;
 965         head = get_first(seq);
 966
 967         if (head)
 968                 while (pos && (head = get_next(seq, head)))
 969                         pos--;
 970         return pos ? NULL : head;
 971 }
 972
 973 static void *seq_start(struct seq_file *seq, loff_t *pos)
 974 {
 975         read_lock_bh(&instances_lock);
 976         return get_idx(seq, *pos);
 977 }
 978
 979 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 980 {
 981         (*pos)++;
 982         return get_next(s, v);
 983 }
 984
 985 static void seq_stop(struct seq_file *s, void *v)
 986 {
 987         read_unlock_bh(&instances_lock);
 988 }
 989
 990 static int seq_show(struct seq_file *s, void *v)
 991 {
 992         const struct nfulnl_instance *inst = v;
 993
 994         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 995                           inst->group_num,
 996                           inst->peer_pid, inst->qlen,
 997                           inst->copy_mode, inst->copy_range,
 998                           inst->flushtimeout, atomic_read(&inst->use));
 999 }
1000
1001 static struct seq_operations nful_seq_ops = {
1002         .start  = seq_start,
1003         .next   = seq_next,
1004         .stop   = seq_stop,
1005         .show   = seq_show,
1006 };
1007
1008 static int nful_open(struct inode *inode, struct file *file)
1009 {
1010         struct seq_file *seq;
1011         struct iter_state *is;
1012         int ret;
1013
1014         is = kzalloc(sizeof(*is), GFP_KERNEL);
1015         if (!is)
1016                 return -ENOMEM;
1017         ret = seq_open(file, &nful_seq_ops);
1018         if (ret < 0)
1019                 goto out_free;
1020         seq = file->private_data;
1021         seq->private = is;
1022         return ret;
1023 out_free:
1024         kfree(is);
1025         return ret;
1026 }
1027
1028 static struct file_operations nful_file_ops = {
1029         .owner   = THIS_MODULE,
1030         .open    = nful_open,
1031         .read    = seq_read,
1032         .llseek  = seq_lseek,
1033         .release = seq_release_private,
1034 };
1035
1036 #endif /* PROC_FS */
1037
1038 static int __init nfnetlink_log_init(void)
1039 {
1040         int i, status = -ENOMEM;
1041 #ifdef CONFIG_PROC_FS
1042         struct proc_dir_entry *proc_nful;
1043 #endif
1044
1045         for (i = 0; i < INSTANCE_BUCKETS; i++)
1046                 INIT_HLIST_HEAD(&instance_table[i]);
1047
1048         /* it's not really all that important to have a random value, so
1049          * we can do this from the init function, even if there hasn't
1050          * been that much entropy yet */
1051         get_random_bytes(&hash_init, sizeof(hash_init));
1052
1053         netlink_register_notifier(&nfulnl_rtnl_notifier);
1054         status = nfnetlink_subsys_register(&nfulnl_subsys);
1055         if (status < 0) {
1056                 printk(KERN_ERR "log: failed to create netlink socket\n");
1057                 goto cleanup_netlink_notifier;
1058         }
1059
1060 #ifdef CONFIG_PROC_FS
1061         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1062                                       proc_net_netfilter);
1063         if (!proc_nful)
1064                 goto cleanup_subsys;
1065         proc_nful->proc_fops = &nful_file_ops;
1066 #endif
1067         return status;
1068
1069 #ifdef CONFIG_PROC_FS
1070 cleanup_subsys:
1071         nfnetlink_subsys_unregister(&nfulnl_subsys);
1072 #endif
1073 cleanup_netlink_notifier:
1074         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1075         return status;
1076 }
1077
1078 static void __exit nfnetlink_log_fini(void)
1079 {
1080         nf_log_unregister_logger(&nfulnl_logger);
1081 #ifdef CONFIG_PROC_FS
1082         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1083 #endif
1084         nfnetlink_subsys_unregister(&nfulnl_subsys);
1085         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1086 }
1087
1088 MODULE_DESCRIPTION("netfilter userspace logging");
1089 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1090 MODULE_LICENSE("GPL");
1091 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1092
1093 module_init(nfnetlink_log_init);
1094 module_exit(nfnetlink_log_fini);