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)
 412 {
 413         unsigned char *old_tail;
 414         struct nfulnl_msg_packet_hdr pmsg;
 415         struct nlmsghdr *nlh;
 416         struct nfgenmsg *nfmsg;
 417         u_int32_t 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        = htons(skb->protocol);
 431         pmsg.hook               = hooknum;
 432
 433         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 434
 435         if (prefix) {
 436                 int slen = strlen(prefix);
 437                 if (slen > NFULNL_PREFIXLEN)
 438                         slen = NFULNL_PREFIXLEN;
 439                 NFA_PUT(inst->skb, NFULA_PREFIX, slen, prefix);
 440         }
 441
 442         if (indev) {
 443                 tmp_uint = htonl(indev->ifindex);
 444 #ifndef CONFIG_BRIDGE_NETFILTER
 445                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
 446                         &tmp_uint);
 447 #else
 448                 if (pf == PF_BRIDGE) {
 449                         /* Case 1: outdev is physical input device, we need to
 450                          * look for bridge group (when called from
 451                          * netfilter_bridge) */
 452                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 453                                 sizeof(tmp_uint), &tmp_uint);
 454                         /* this is the bridge group "brX" */
 455                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
 456                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 457                                 sizeof(tmp_uint), &tmp_uint);
 458                 } else {
 459                         /* Case 2: indev is bridge group, we need to look for
 460                          * physical device (when called from ipv4) */
 461                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 462                                 sizeof(tmp_uint), &tmp_uint);
 463                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
 464                                 tmp_uint =
 465                                     htonl(skb->nf_bridge->physindev->ifindex);
 466                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 467                                         sizeof(tmp_uint), &tmp_uint);
 468                         }
 469                 }
 470 #endif
 471         }
 472
 473         if (outdev) {
 474                 tmp_uint = htonl(outdev->ifindex);
 475 #ifndef CONFIG_BRIDGE_NETFILTER
 476                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 477                         &tmp_uint);
 478 #else
 479                 if (pf == PF_BRIDGE) {
 480                         /* Case 1: outdev is physical output device, we need to
 481                          * look for bridge group (when called from
 482                          * netfilter_bridge) */
 483                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 484                                 sizeof(tmp_uint), &tmp_uint);
 485                         /* this is the bridge group "brX" */
 486                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
 487                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 488                                 sizeof(tmp_uint), &tmp_uint);
 489                 } else {
 490                         /* Case 2: indev is a bridge group, we need to look
 491                          * for physical device (when called from ipv4) */
 492                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 493                                 sizeof(tmp_uint), &tmp_uint);
 494                         if (skb->nf_bridge) {
 495                                 tmp_uint =
 496                                     htonl(skb->nf_bridge->physoutdev->ifindex);
 497                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 498                                         sizeof(tmp_uint), &tmp_uint);
 499                         }
 500                 }
 501 #endif
 502         }
 503
 504         if (skb->nfmark) {
 505                 tmp_uint = htonl(skb->nfmark);
 506                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
 507         }
 508
 509         if (indev && skb->dev && skb->dev->hard_header_parse) {
 510                 struct nfulnl_msg_packet_hw phw;
 511
 512                 phw.hw_addrlen =
 513                         skb->dev->hard_header_parse((struct sk_buff *)skb,
 514                                                     phw.hw_addr);
 515                 phw.hw_addrlen = htons(phw.hw_addrlen);
 516                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 517         }
 518
 519         if (skb->tstamp.off_sec) {
 520                 struct nfulnl_msg_packet_timestamp ts;
 521
 522                 ts.sec = cpu_to_be64(skb->tstamp.off_sec);
 523                 ts.usec = cpu_to_be64(skb->tstamp.off_usec);
 524
 525                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 526         }
 527
 528         /* UID */
 529         if (skb->sk) {
 530                 read_lock_bh(&skb->sk->sk_callback_lock);
 531                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 532                         u_int32_t uid = htonl(skb->sk->sk_socket->file->f_uid);
 533                         /* need to unlock here since NFA_PUT may goto */
 534                         read_unlock_bh(&skb->sk->sk_callback_lock);
 535                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
 536                 } else
 537                         read_unlock_bh(&skb->sk->sk_callback_lock);
 538         }
 539
 540         /* local sequence number */
 541         if (inst->flags & NFULNL_CFG_F_SEQ) {
 542                 tmp_uint = htonl(inst->seq++);
 543                 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
 544         }
 545         /* global sequence number */
 546         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
 547                 tmp_uint = atomic_inc_return(&global_seq);
 548                 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
 549         }
 550
 551         if (data_len) {
 552                 struct nfattr *nfa;
 553                 int size = NFA_LENGTH(data_len);
 554
 555                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
 556                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 557                         goto nlmsg_failure;
 558                 }
 559
 560                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
 561                 nfa->nfa_type = NFULA_PAYLOAD;
 562                 nfa->nfa_len = size;
 563
 564                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
 565                         BUG();
 566         }
 567
 568         nlh->nlmsg_len = inst->skb->tail - old_tail;
 569         return 0;
 570
 571 nlmsg_failure:
 572         UDEBUG("nlmsg_failure\n");
 573 nfattr_failure:
 574         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 575         return -1;
 576 }
 577
 578 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 579
 580 static struct nf_loginfo default_loginfo = {
 581         .type =         NF_LOG_TYPE_ULOG,
 582         .u = {
 583                 .ulog = {
 584                         .copy_len       = 0xffff,
 585                         .group          = 0,
 586                         .qthreshold     = 1,
 587                 },
 588         },
 589 };
 590
 591 /* log handler for internal netfilter logging api */
 592 static void
 593 nfulnl_log_packet(unsigned int pf,
 594                   unsigned int hooknum,
 595                   const struct sk_buff *skb,
 596                   const struct net_device *in,
 597                   const struct net_device *out,
 598                   const struct nf_loginfo *li_user,
 599                   const char *prefix)
 600 {
 601         unsigned int size, data_len;
 602         struct nfulnl_instance *inst;
 603         const struct nf_loginfo *li;
 604         unsigned int qthreshold;
 605         unsigned int nlbufsiz;
 606
 607         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 608                 li = li_user;
 609         else
 610                 li = &default_loginfo;
 611
 612         inst = instance_lookup_get(li->u.ulog.group);
 613         if (!inst)
 614                 inst = instance_lookup_get(0);
 615         if (!inst) {
 616                 PRINTR("nfnetlink_log: trying to log packet, "
 617                         "but no instance for group %u\n", li->u.ulog.group);
 618                 return;
 619         }
 620
 621         /* all macros expand to constant values at compile time */
 622         /* FIXME: do we want to make the size calculation conditional based on
 623          * what is actually present?  way more branches and checks, but more
 624          * memory efficient... */
 625         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 626                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
 627                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 628                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 629 #ifdef CONFIG_BRIDGE_NETFILTER
 630                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 631                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 632 #endif
 633                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
 634                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
 635                 + NFA_SPACE(NFULNL_PREFIXLEN)   /* prefix */
 636                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
 637                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
 638
 639         UDEBUG("initial size=%u\n", size);
 640
 641         spin_lock_bh(&inst->lock);
 642
 643         if (inst->flags & NFULNL_CFG_F_SEQ)
 644                 size += NFA_SPACE(sizeof(u_int32_t));
 645         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 646                 size += NFA_SPACE(sizeof(u_int32_t));
 647
 648         qthreshold = inst->qthreshold;
 649         /* per-rule qthreshold overrides per-instance */
 650         if (qthreshold > li->u.ulog.qthreshold)
 651                 qthreshold = li->u.ulog.qthreshold;
 652
 653         switch (inst->copy_mode) {
 654         case NFULNL_COPY_META:
 655         case NFULNL_COPY_NONE:
 656                 data_len = 0;
 657                 break;
 658
 659         case NFULNL_COPY_PACKET:
 660                 if (inst->copy_range == 0
 661                     || inst->copy_range > skb->len)
 662                         data_len = skb->len;
 663                 else
 664                         data_len = inst->copy_range;
 665
 666                 size += NFA_SPACE(data_len);
 667                 UDEBUG("copy_packet, therefore size now %u\n", size);
 668                 break;
 669
 670         default:
 671                 spin_unlock_bh(&inst->lock);
 672                 instance_put(inst);
 673                 return;
 674         }
 675
 676         if (size > inst->nlbufsiz)
 677                 nlbufsiz = size;
 678         else
 679                 nlbufsiz = inst->nlbufsiz;
 680
 681         if (!inst->skb) {
 682                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 683                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 684                                 inst->nlbufsiz, size);
 685                         goto alloc_failure;
 686                 }
 687         } else if (inst->qlen >= qthreshold ||
 688                    size > skb_tailroom(inst->skb)) {
 689                 /* either the queue len is too high or we don't have
 690                  * enough room in the skb left. flush to userspace. */
 691                 UDEBUG("flushing old skb\n");
 692
 693                 __nfulnl_send(inst);
 694
 695                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 696                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 697                                 inst->nlbufsiz, size);
 698                         goto alloc_failure;
 699                 }
 700         }
 701
 702         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
 703         inst->qlen++;
 704
 705         __build_packet_message(inst, skb, data_len, pf,
 706                                 hooknum, in, out, li, prefix);
 707
 708         /* timer_pending always called within inst->lock, so there
 709          * is no chance of a race here */
 710         if (!timer_pending(&inst->timer)) {
 711                 instance_get(inst);
 712                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 713                 add_timer(&inst->timer);
 714         }
 715         spin_unlock_bh(&inst->lock);
 716
 717         return;
 718
 719 alloc_failure:
 720         spin_unlock_bh(&inst->lock);
 721         instance_put(inst);
 722         UDEBUG("error allocating skb\n");
 723         /* FIXME: statistics */
 724 }
 725
 726 static int
 727 nfulnl_rcv_nl_event(struct notifier_block *this,
 728                    unsigned long event, void *ptr)
 729 {
 730         struct netlink_notify *n = ptr;
 731
 732         if (event == NETLINK_URELEASE &&
 733             n->protocol == NETLINK_NETFILTER && n->pid) {
 734                 int i;
 735
 736                 /* destroy all instances for this pid */
 737                 write_lock_bh(&instances_lock);
 738                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 739                         struct hlist_node *tmp, *t2;
 740                         struct nfulnl_instance *inst;
 741                         struct hlist_head *head = &instance_table[i];
 742
 743                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 744                                 UDEBUG("node = %p\n", inst);
 745                                 if (n->pid == inst->peer_pid)
 746                                         __instance_destroy(inst);
 747                         }
 748                 }
 749                 write_unlock_bh(&instances_lock);
 750         }
 751         return NOTIFY_DONE;
 752 }
 753
 754 static struct notifier_block nfulnl_rtnl_notifier = {
 755         .notifier_call  = nfulnl_rcv_nl_event,
 756 };
 757
 758 static int
 759 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 760                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 761 {
 762         return -ENOTSUPP;
 763 }
 764
 765 static struct nf_logger nfulnl_logger = {
 766         .name   = "nfnetlink_log",
 767         .logfn  = &nfulnl_log_packet,
 768         .me     = THIS_MODULE,
 769 };
 770
 771 static const int nfula_min[NFULA_MAX] = {
 772         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
 773         [NFULA_MARK-1]          = sizeof(u_int32_t),
 774         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
 775         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
 776         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
 777         [NFULA_IFINDEX_PHYSINDEV-1]     = sizeof(u_int32_t),
 778         [NFULA_IFINDEX_PHYSOUTDEV-1]    = sizeof(u_int32_t),
 779         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
 780         [NFULA_PAYLOAD-1]       = 0,
 781         [NFULA_PREFIX-1]        = 0,
 782         [NFULA_UID-1]           = sizeof(u_int32_t),
 783         [NFULA_SEQ-1]           = sizeof(u_int32_t),
 784         [NFULA_SEQ_GLOBAL-1]    = sizeof(u_int32_t),
 785 };
 786
 787 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 788         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
 789         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
 790         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
 791         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
 792         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
 793         [NFULA_CFG_FLAGS-1]     = sizeof(u_int16_t),
 794 };
 795
 796 static int
 797 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 798                    struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
 799 {
 800         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 801         u_int16_t group_num = ntohs(nfmsg->res_id);
 802         struct nfulnl_instance *inst;
 803         int ret = 0;
 804
 805         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 806
 807         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
 808                 UDEBUG("bad attribute size\n");
 809                 return -EINVAL;
 810         }
 811
 812         inst = instance_lookup_get(group_num);
 813         if (nfula[NFULA_CFG_CMD-1]) {
 814                 u_int8_t pf = nfmsg->nfgen_family;
 815                 struct nfulnl_msg_config_cmd *cmd;
 816                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
 817                 UDEBUG("found CFG_CMD for\n");
 818
 819                 switch (cmd->command) {
 820                 case NFULNL_CFG_CMD_BIND:
 821                         if (inst) {
 822                                 ret = -EBUSY;
 823                                 goto out_put;
 824                         }
 825
 826                         inst = instance_create(group_num,
 827                                                NETLINK_CB(skb).pid);
 828                         if (!inst) {
 829                                 ret = -EINVAL;
 830                                 goto out_put;
 831                         }
 832                         break;
 833                 case NFULNL_CFG_CMD_UNBIND:
 834                         if (!inst) {
 835                                 ret = -ENODEV;
 836                                 goto out_put;
 837                         }
 838
 839                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
 840                                 ret = -EPERM;
 841                                 goto out_put;
 842                         }
 843
 844                         instance_destroy(inst);
 845                         break;
 846                 case NFULNL_CFG_CMD_PF_BIND:
 847                         UDEBUG("registering log handler for pf=%u\n", pf);
 848                         ret = nf_log_register(pf, &nfulnl_logger);
 849                         break;
 850                 case NFULNL_CFG_CMD_PF_UNBIND:
 851                         UDEBUG("unregistering log handler for pf=%u\n", pf);
 852                         /* This is a bug and a feature.  We cannot unregister
 853                          * other handlers, like nfnetlink_inst can */
 854                         nf_log_unregister_pf(pf);
 855                         break;
 856                 default:
 857                         ret = -EINVAL;
 858                         break;
 859                 }
 860         } else {
 861                 if (!inst) {
 862                         UDEBUG("no config command, and no instance for "
 863                                 "group=%u pid=%u =>ENOENT\n",
 864                                 group_num, NETLINK_CB(skb).pid);
 865                         ret = -ENOENT;
 866                         goto out_put;
 867                 }
 868
 869                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
 870                         UDEBUG("no config command, and wrong pid\n");
 871                         ret = -EPERM;
 872                         goto out_put;
 873                 }
 874         }
 875
 876         if (nfula[NFULA_CFG_MODE-1]) {
 877                 struct nfulnl_msg_config_mode *params;
 878                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
 879
 880                 nfulnl_set_mode(inst, params->copy_mode,
 881                                 ntohs(params->copy_range));
 882         }
 883
 884         if (nfula[NFULA_CFG_TIMEOUT-1]) {
 885                 u_int32_t timeout =
 886                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
 887
 888                 nfulnl_set_timeout(inst, ntohl(timeout));
 889         }
 890
 891         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
 892                 u_int32_t nlbufsiz =
 893                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
 894
 895                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 896         }
 897
 898         if (nfula[NFULA_CFG_QTHRESH-1]) {
 899                 u_int32_t qthresh =
 900                         *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
 901
 902                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 903         }
 904
 905         if (nfula[NFULA_CFG_FLAGS-1]) {
 906                 u_int16_t flags =
 907                         *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
 908                 nfulnl_set_flags(inst, ntohs(flags));
 909         }
 910
 911 out_put:
 912         instance_put(inst);
 913         return ret;
 914 }
 915
 916 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 917         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 918                                     .attr_count = NFULA_MAX, },
 919         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 920                                     .attr_count = NFULA_CFG_MAX, },
 921 };
 922
 923 static struct nfnetlink_subsystem nfulnl_subsys = {
 924         .name           = "log",
 925         .subsys_id      = NFNL_SUBSYS_ULOG,
 926         .cb_count       = NFULNL_MSG_MAX,
 927         .cb             = nfulnl_cb,
 928 };
 929
 930 #ifdef CONFIG_PROC_FS
 931 struct iter_state {
 932         unsigned int bucket;
 933 };
 934
 935 static struct hlist_node *get_first(struct seq_file *seq)
 936 {
 937         struct iter_state *st = seq->private;
 938
 939         if (!st)
 940                 return NULL;
 941
 942         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 943                 if (!hlist_empty(&instance_table[st->bucket]))
 944                         return instance_table[st->bucket].first;
 945         }
 946         return NULL;
 947 }
 948
 949 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
 950 {
 951         struct iter_state *st = seq->private;
 952
 953         h = h->next;
 954         while (!h) {
 955                 if (++st->bucket >= INSTANCE_BUCKETS)
 956                         return NULL;
 957
 958                 h = instance_table[st->bucket].first;
 959         }
 960         return h;
 961 }
 962
 963 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
 964 {
 965         struct hlist_node *head;
 966         head = get_first(seq);
 967
 968         if (head)
 969                 while (pos && (head = get_next(seq, head)))
 970                         pos--;
 971         return pos ? NULL : head;
 972 }
 973
 974 static void *seq_start(struct seq_file *seq, loff_t *pos)
 975 {
 976         read_lock_bh(&instances_lock);
 977         return get_idx(seq, *pos);
 978 }
 979
 980 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 981 {
 982         (*pos)++;
 983         return get_next(s, v);
 984 }
 985
 986 static void seq_stop(struct seq_file *s, void *v)
 987 {
 988         read_unlock_bh(&instances_lock);
 989 }
 990
 991 static int seq_show(struct seq_file *s, void *v)
 992 {
 993         const struct nfulnl_instance *inst = v;
 994
 995         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 996                           inst->group_num,
 997                           inst->peer_pid, inst->qlen,
 998                           inst->copy_mode, inst->copy_range,
 999                           inst->flushtimeout, atomic_read(&inst->use));
1000 }
1001
1002 static struct seq_operations nful_seq_ops = {
1003         .start  = seq_start,
1004         .next   = seq_next,
1005         .stop   = seq_stop,
1006         .show   = seq_show,
1007 };
1008
1009 static int nful_open(struct inode *inode, struct file *file)
1010 {
1011         struct seq_file *seq;
1012         struct iter_state *is;
1013         int ret;
1014
1015         is = kzalloc(sizeof(*is), GFP_KERNEL);
1016         if (!is)
1017                 return -ENOMEM;
1018         ret = seq_open(file, &nful_seq_ops);
1019         if (ret < 0)
1020                 goto out_free;
1021         seq = file->private_data;
1022         seq->private = is;
1023         return ret;
1024 out_free:
1025         kfree(is);
1026         return ret;
1027 }
1028
1029 static struct file_operations nful_file_ops = {
1030         .owner   = THIS_MODULE,
1031         .open    = nful_open,
1032         .read    = seq_read,
1033         .llseek  = seq_lseek,
1034         .release = seq_release_private,
1035 };
1036
1037 #endif /* PROC_FS */
1038
1039 static int __init nfnetlink_log_init(void)
1040 {
1041         int i, status = -ENOMEM;
1042 #ifdef CONFIG_PROC_FS
1043         struct proc_dir_entry *proc_nful;
1044 #endif
1045
1046         for (i = 0; i < INSTANCE_BUCKETS; i++)
1047                 INIT_HLIST_HEAD(&instance_table[i]);
1048
1049         /* it's not really all that important to have a random value, so
1050          * we can do this from the init function, even if there hasn't
1051          * been that much entropy yet */
1052         get_random_bytes(&hash_init, sizeof(hash_init));
1053
1054         netlink_register_notifier(&nfulnl_rtnl_notifier);
1055         status = nfnetlink_subsys_register(&nfulnl_subsys);
1056         if (status < 0) {
1057                 printk(KERN_ERR "log: failed to create netlink socket\n");
1058                 goto cleanup_netlink_notifier;
1059         }
1060
1061 #ifdef CONFIG_PROC_FS
1062         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1063                                       proc_net_netfilter);
1064         if (!proc_nful)
1065                 goto cleanup_subsys;
1066         proc_nful->proc_fops = &nful_file_ops;
1067 #endif
1068         return status;
1069
1070 #ifdef CONFIG_PROC_FS
1071 cleanup_subsys:
1072         nfnetlink_subsys_unregister(&nfulnl_subsys);
1073 #endif
1074 cleanup_netlink_notifier:
1075         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1076         return status;
1077 }
1078
1079 static void __exit nfnetlink_log_fini(void)
1080 {
1081         nf_log_unregister_logger(&nfulnl_logger);
1082 #ifdef CONFIG_PROC_FS
1083         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1084 #endif
1085         nfnetlink_subsys_unregister(&nfulnl_subsys);
1086         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1087 }
1088
1089 MODULE_DESCRIPTION("netfilter userspace logging");
1090 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1091 MODULE_LICENSE("GPL");
1092 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1093
1094 module_init(nfnetlink_log_init);
1095 module_exit(nfnetlink_log_fini);