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 = ntohs(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->qlen > 1)
 370                 inst->lastnlh->nlmsg_type = NLMSG_DONE;
 371
 372         status = nfnetlink_unicast(inst->skb, inst->peer_pid, MSG_DONTWAIT);
 373         if (status < 0) {
 374                 UDEBUG("netlink_unicast() failed\n");
 375                 /* FIXME: statistics */
 376         }
 377
 378         inst->qlen = 0;
 379         inst->skb = NULL;
 380         inst->lastnlh = NULL;
 381
 382         return status;
 383 }
 384
 385 static void nfulnl_timer(unsigned long data)
 386 {
 387         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 388
 389         UDEBUG("timer function called, flushing buffer\n");
 390
 391         spin_lock_bh(&inst->lock);
 392         __nfulnl_send(inst);
 393         instance_put(inst);
 394         spin_unlock_bh(&inst->lock);
 395 }
 396
 397 /* This is an inline function, we don't really care about a long
 398  * list of arguments */
 399 static inline int
 400 __build_packet_message(struct nfulnl_instance *inst,
 401                         const struct sk_buff *skb,
 402                         unsigned int data_len,
 403                         unsigned int pf,
 404                         unsigned int hooknum,
 405                         const struct net_device *indev,
 406                         const struct net_device *outdev,
 407                         const struct nf_loginfo *li,
 408                         const char *prefix)
 409 {
 410         unsigned char *old_tail;
 411         struct nfulnl_msg_packet_hdr pmsg;
 412         struct nlmsghdr *nlh;
 413         struct nfgenmsg *nfmsg;
 414         u_int32_t tmp_uint;
 415
 416         UDEBUG("entered\n");
 417
 418         old_tail = inst->skb->tail;
 419         nlh = NLMSG_PUT(inst->skb, 0, 0,
 420                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 421                         sizeof(struct nfgenmsg));
 422         nfmsg = NLMSG_DATA(nlh);
 423         nfmsg->nfgen_family = pf;
 424         nfmsg->version = NFNETLINK_V0;
 425         nfmsg->res_id = htons(inst->group_num);
 426
 427         pmsg.hw_protocol        = htons(skb->protocol);
 428         pmsg.hook               = hooknum;
 429
 430         NFA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 431
 432         if (prefix) {
 433                 int slen = strlen(prefix);
 434                 if (slen > NFULNL_PREFIXLEN)
 435                         slen = NFULNL_PREFIXLEN;
 436                 NFA_PUT(inst->skb, NFULA_PREFIX, slen, prefix);
 437         }
 438
 439         if (indev) {
 440                 tmp_uint = htonl(indev->ifindex);
 441 #ifndef CONFIG_BRIDGE_NETFILTER
 442                 NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV, sizeof(tmp_uint),
 443                         &tmp_uint);
 444 #else
 445                 if (pf == PF_BRIDGE) {
 446                         /* Case 1: outdev is physical input device, we need to
 447                          * look for bridge group (when called from
 448                          * netfilter_bridge) */
 449                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 450                                 sizeof(tmp_uint), &tmp_uint);
 451                         /* this is the bridge group "brX" */
 452                         tmp_uint = htonl(indev->br_port->br->dev->ifindex);
 453                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 454                                 sizeof(tmp_uint), &tmp_uint);
 455                 } else {
 456                         /* Case 2: indev is bridge group, we need to look for
 457                          * physical device (when called from ipv4) */
 458                         NFA_PUT(inst->skb, NFULA_IFINDEX_INDEV,
 459                                 sizeof(tmp_uint), &tmp_uint);
 460                         if (skb->nf_bridge && skb->nf_bridge->physindev) {
 461                                 tmp_uint =
 462                                     htonl(skb->nf_bridge->physindev->ifindex);
 463                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 464                                         sizeof(tmp_uint), &tmp_uint);
 465                         }
 466                 }
 467 #endif
 468         }
 469
 470         if (outdev) {
 471                 tmp_uint = htonl(outdev->ifindex);
 472 #ifndef CONFIG_BRIDGE_NETFILTER
 473                 NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 474                         &tmp_uint);
 475 #else
 476                 if (pf == PF_BRIDGE) {
 477                         /* Case 1: outdev is physical output device, we need to
 478                          * look for bridge group (when called from
 479                          * netfilter_bridge) */
 480                         NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 481                                 sizeof(tmp_uint), &tmp_uint);
 482                         /* this is the bridge group "brX" */
 483                         tmp_uint = htonl(outdev->br_port->br->dev->ifindex);
 484                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 485                                 sizeof(tmp_uint), &tmp_uint);
 486                 } else {
 487                         /* Case 2: indev is a bridge group, we need to look
 488                          * for physical device (when called from ipv4) */
 489                         NFA_PUT(inst->skb, NFULA_IFINDEX_OUTDEV,
 490                                 sizeof(tmp_uint), &tmp_uint);
 491                         if (skb->nf_bridge) {
 492                                 tmp_uint =
 493                                     htonl(skb->nf_bridge->physoutdev->ifindex);
 494                                 NFA_PUT(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 495                                         sizeof(tmp_uint), &tmp_uint);
 496                         }
 497                 }
 498 #endif
 499         }
 500
 501         if (skb->nfmark) {
 502                 tmp_uint = htonl(skb->nfmark);
 503                 NFA_PUT(inst->skb, NFULA_MARK, sizeof(tmp_uint), &tmp_uint);
 504         }
 505
 506         if (indev && skb->dev && skb->dev->hard_header_parse) {
 507                 struct nfulnl_msg_packet_hw phw;
 508
 509                 phw.hw_addrlen =
 510                         skb->dev->hard_header_parse((struct sk_buff *)skb,
 511                                                     phw.hw_addr);
 512                 phw.hw_addrlen = htons(phw.hw_addrlen);
 513                 NFA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 514         }
 515
 516         if (skb->tstamp.off_sec) {
 517                 struct nfulnl_msg_packet_timestamp ts;
 518
 519                 ts.sec = cpu_to_be64(skb->tstamp.off_sec);
 520                 ts.usec = cpu_to_be64(skb->tstamp.off_usec);
 521
 522                 NFA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 523         }
 524
 525         /* UID */
 526         if (skb->sk) {
 527                 read_lock_bh(&skb->sk->sk_callback_lock);
 528                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 529                         u_int32_t uid = htonl(skb->sk->sk_socket->file->f_uid);
 530                         /* need to unlock here since NFA_PUT may goto */
 531                         read_unlock_bh(&skb->sk->sk_callback_lock);
 532                         NFA_PUT(inst->skb, NFULA_UID, sizeof(uid), &uid);
 533                 } else
 534                         read_unlock_bh(&skb->sk->sk_callback_lock);
 535         }
 536
 537         /* local sequence number */
 538         if (inst->flags & NFULNL_CFG_F_SEQ) {
 539                 tmp_uint = htonl(inst->seq++);
 540                 NFA_PUT(inst->skb, NFULA_SEQ, sizeof(tmp_uint), &tmp_uint);
 541         }
 542         /* global sequence number */
 543         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) {
 544                 tmp_uint = atomic_inc_return(&global_seq);
 545                 NFA_PUT(inst->skb, NFULA_SEQ_GLOBAL, sizeof(tmp_uint), &tmp_uint);
 546         }
 547
 548         if (data_len) {
 549                 struct nfattr *nfa;
 550                 int size = NFA_LENGTH(data_len);
 551
 552                 if (skb_tailroom(inst->skb) < (int)NFA_SPACE(data_len)) {
 553                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 554                         goto nlmsg_failure;
 555                 }
 556
 557                 nfa = (struct nfattr *)skb_put(inst->skb, NFA_ALIGN(size));
 558                 nfa->nfa_type = NFULA_PAYLOAD;
 559                 nfa->nfa_len = size;
 560
 561                 if (skb_copy_bits(skb, 0, NFA_DATA(nfa), data_len))
 562                         BUG();
 563         }
 564
 565         nlh->nlmsg_len = inst->skb->tail - old_tail;
 566         return 0;
 567
 568 nlmsg_failure:
 569         UDEBUG("nlmsg_failure\n");
 570 nfattr_failure:
 571         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 572         return -1;
 573 }
 574
 575 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 576
 577 static struct nf_loginfo default_loginfo = {
 578         .type =         NF_LOG_TYPE_ULOG,
 579         .u = {
 580                 .ulog = {
 581                         .copy_len       = 0xffff,
 582                         .group          = 0,
 583                         .qthreshold     = 1,
 584                 },
 585         },
 586 };
 587
 588 /* log handler for internal netfilter logging api */
 589 static void
 590 nfulnl_log_packet(unsigned int pf,
 591                   unsigned int hooknum,
 592                   const struct sk_buff *skb,
 593                   const struct net_device *in,
 594                   const struct net_device *out,
 595                   const struct nf_loginfo *li_user,
 596                   const char *prefix)
 597 {
 598         unsigned int size, data_len;
 599         struct nfulnl_instance *inst;
 600         const struct nf_loginfo *li;
 601         unsigned int qthreshold;
 602         unsigned int nlbufsiz;
 603
 604         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 605                 li = li_user;
 606         else
 607                 li = &default_loginfo;
 608
 609         inst = instance_lookup_get(li->u.ulog.group);
 610         if (!inst)
 611                 inst = instance_lookup_get(0);
 612         if (!inst) {
 613                 PRINTR("nfnetlink_log: trying to log packet, "
 614                         "but no instance for group %u\n", li->u.ulog.group);
 615                 return;
 616         }
 617
 618         /* all macros expand to constant values at compile time */
 619         /* FIXME: do we want to make the size calculation conditional based on
 620          * what is actually present?  way more branches and checks, but more
 621          * memory efficient... */
 622         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 623                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hdr))
 624                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 625                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 626 #ifdef CONFIG_BRIDGE_NETFILTER
 627                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 628                 + NFA_SPACE(sizeof(u_int32_t))  /* ifindex */
 629 #endif
 630                 + NFA_SPACE(sizeof(u_int32_t))  /* mark */
 631                 + NFA_SPACE(sizeof(u_int32_t))  /* uid */
 632                 + NFA_SPACE(NFULNL_PREFIXLEN)   /* prefix */
 633                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_hw))
 634                 + NFA_SPACE(sizeof(struct nfulnl_msg_packet_timestamp));
 635
 636         UDEBUG("initial size=%u\n", size);
 637
 638         spin_lock_bh(&inst->lock);
 639
 640         if (inst->flags & NFULNL_CFG_F_SEQ)
 641                 size += NFA_SPACE(sizeof(u_int32_t));
 642         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 643                 size += NFA_SPACE(sizeof(u_int32_t));
 644
 645         qthreshold = inst->qthreshold;
 646         /* per-rule qthreshold overrides per-instance */
 647         if (qthreshold > li->u.ulog.qthreshold)
 648                 qthreshold = li->u.ulog.qthreshold;
 649
 650         switch (inst->copy_mode) {
 651         case NFULNL_COPY_META:
 652         case NFULNL_COPY_NONE:
 653                 data_len = 0;
 654                 break;
 655
 656         case NFULNL_COPY_PACKET:
 657                 if (inst->copy_range == 0
 658                     || inst->copy_range > skb->len)
 659                         data_len = skb->len;
 660                 else
 661                         data_len = inst->copy_range;
 662
 663                 size += NFA_SPACE(data_len);
 664                 UDEBUG("copy_packet, therefore size now %u\n", size);
 665                 break;
 666
 667         default:
 668                 spin_unlock_bh(&inst->lock);
 669                 instance_put(inst);
 670                 return;
 671         }
 672
 673         if (size > inst->nlbufsiz)
 674                 nlbufsiz = size;
 675         else
 676                 nlbufsiz = inst->nlbufsiz;
 677
 678         if (!inst->skb) {
 679                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 680                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 681                                 inst->nlbufsiz, size);
 682                         goto alloc_failure;
 683                 }
 684         } else if (inst->qlen >= qthreshold ||
 685                    size > skb_tailroom(inst->skb)) {
 686                 /* either the queue len is too high or we don't have
 687                  * enough room in the skb left. flush to userspace. */
 688                 UDEBUG("flushing old skb\n");
 689
 690                 __nfulnl_send(inst);
 691
 692                 if (!(inst->skb = nfulnl_alloc_skb(nlbufsiz, size))) {
 693                         UDEBUG("error in nfulnl_alloc_skb(%u, %u)\n",
 694                                 inst->nlbufsiz, size);
 695                         goto alloc_failure;
 696                 }
 697         }
 698
 699         UDEBUG("qlen %d, qthreshold %d\n", inst->qlen, qthreshold);
 700         inst->qlen++;
 701
 702         __build_packet_message(inst, skb, data_len, pf,
 703                                 hooknum, in, out, li, prefix);
 704
 705         /* timer_pending always called within inst->lock, so there
 706          * is no chance of a race here */
 707         if (!timer_pending(&inst->timer)) {
 708                 instance_get(inst);
 709                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 710                 add_timer(&inst->timer);
 711         }
 712         spin_unlock_bh(&inst->lock);
 713
 714         return;
 715
 716 alloc_failure:
 717         spin_unlock_bh(&inst->lock);
 718         instance_put(inst);
 719         UDEBUG("error allocating skb\n");
 720         /* FIXME: statistics */
 721 }
 722
 723 static int
 724 nfulnl_rcv_nl_event(struct notifier_block *this,
 725                    unsigned long event, void *ptr)
 726 {
 727         struct netlink_notify *n = ptr;
 728
 729         if (event == NETLINK_URELEASE &&
 730             n->protocol == NETLINK_NETFILTER && n->pid) {
 731                 int i;
 732
 733                 /* destroy all instances for this pid */
 734                 write_lock_bh(&instances_lock);
 735                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 736                         struct hlist_node *tmp, *t2;
 737                         struct nfulnl_instance *inst;
 738                         struct hlist_head *head = &instance_table[i];
 739
 740                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 741                                 UDEBUG("node = %p\n", inst);
 742                                 if (n->pid == inst->peer_pid)
 743                                         __instance_destroy(inst);
 744                         }
 745                 }
 746                 write_unlock_bh(&instances_lock);
 747         }
 748         return NOTIFY_DONE;
 749 }
 750
 751 static struct notifier_block nfulnl_rtnl_notifier = {
 752         .notifier_call  = nfulnl_rcv_nl_event,
 753 };
 754
 755 static int
 756 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 757                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 758 {
 759         return -ENOTSUPP;
 760 }
 761
 762 static struct nf_logger nfulnl_logger = {
 763         .name   = "nfnetlink_log",
 764         .logfn  = &nfulnl_log_packet,
 765         .me     = THIS_MODULE,
 766 };
 767
 768 static const int nfula_min[NFULA_MAX] = {
 769         [NFULA_PACKET_HDR-1]    = sizeof(struct nfulnl_msg_packet_hdr),
 770         [NFULA_MARK-1]          = sizeof(u_int32_t),
 771         [NFULA_TIMESTAMP-1]     = sizeof(struct nfulnl_msg_packet_timestamp),
 772         [NFULA_IFINDEX_INDEV-1] = sizeof(u_int32_t),
 773         [NFULA_IFINDEX_OUTDEV-1]= sizeof(u_int32_t),
 774         [NFULA_IFINDEX_PHYSINDEV-1]     = sizeof(u_int32_t),
 775         [NFULA_IFINDEX_PHYSOUTDEV-1]    = sizeof(u_int32_t),
 776         [NFULA_HWADDR-1]        = sizeof(struct nfulnl_msg_packet_hw),
 777         [NFULA_PAYLOAD-1]       = 0,
 778         [NFULA_PREFIX-1]        = 0,
 779         [NFULA_UID-1]           = sizeof(u_int32_t),
 780         [NFULA_SEQ-1]           = sizeof(u_int32_t),
 781         [NFULA_SEQ_GLOBAL-1]    = sizeof(u_int32_t),
 782 };
 783
 784 static const int nfula_cfg_min[NFULA_CFG_MAX] = {
 785         [NFULA_CFG_CMD-1]       = sizeof(struct nfulnl_msg_config_cmd),
 786         [NFULA_CFG_MODE-1]      = sizeof(struct nfulnl_msg_config_mode),
 787         [NFULA_CFG_TIMEOUT-1]   = sizeof(u_int32_t),
 788         [NFULA_CFG_QTHRESH-1]   = sizeof(u_int32_t),
 789         [NFULA_CFG_NLBUFSIZ-1]  = sizeof(u_int32_t),
 790         [NFULA_CFG_FLAGS-1]     = sizeof(u_int16_t),
 791 };
 792
 793 static int
 794 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 795                    struct nlmsghdr *nlh, struct nfattr *nfula[], int *errp)
 796 {
 797         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 798         u_int16_t group_num = ntohs(nfmsg->res_id);
 799         struct nfulnl_instance *inst;
 800         int ret = 0;
 801
 802         UDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 803
 804         if (nfattr_bad_size(nfula, NFULA_CFG_MAX, nfula_cfg_min)) {
 805                 UDEBUG("bad attribute size\n");
 806                 return -EINVAL;
 807         }
 808
 809         inst = instance_lookup_get(group_num);
 810         if (nfula[NFULA_CFG_CMD-1]) {
 811                 u_int8_t pf = nfmsg->nfgen_family;
 812                 struct nfulnl_msg_config_cmd *cmd;
 813                 cmd = NFA_DATA(nfula[NFULA_CFG_CMD-1]);
 814                 UDEBUG("found CFG_CMD for\n");
 815
 816                 switch (cmd->command) {
 817                 case NFULNL_CFG_CMD_BIND:
 818                         if (inst) {
 819                                 ret = -EBUSY;
 820                                 goto out_put;
 821                         }
 822
 823                         inst = instance_create(group_num,
 824                                                NETLINK_CB(skb).pid);
 825                         if (!inst) {
 826                                 ret = -EINVAL;
 827                                 goto out_put;
 828                         }
 829                         break;
 830                 case NFULNL_CFG_CMD_UNBIND:
 831                         if (!inst) {
 832                                 ret = -ENODEV;
 833                                 goto out_put;
 834                         }
 835
 836                         if (inst->peer_pid != NETLINK_CB(skb).pid) {
 837                                 ret = -EPERM;
 838                                 goto out_put;
 839                         }
 840
 841                         instance_destroy(inst);
 842                         break;
 843                 case NFULNL_CFG_CMD_PF_BIND:
 844                         UDEBUG("registering log handler for pf=%u\n", pf);
 845                         ret = nf_log_register(pf, &nfulnl_logger);
 846                         break;
 847                 case NFULNL_CFG_CMD_PF_UNBIND:
 848                         UDEBUG("unregistering log handler for pf=%u\n", pf);
 849                         /* This is a bug and a feature.  We cannot unregister
 850                          * other handlers, like nfnetlink_inst can */
 851                         nf_log_unregister_pf(pf);
 852                         break;
 853                 default:
 854                         ret = -EINVAL;
 855                         break;
 856                 }
 857         } else {
 858                 if (!inst) {
 859                         UDEBUG("no config command, and no instance for "
 860                                 "group=%u pid=%u =>ENOENT\n",
 861                                 group_num, NETLINK_CB(skb).pid);
 862                         ret = -ENOENT;
 863                         goto out_put;
 864                 }
 865
 866                 if (inst->peer_pid != NETLINK_CB(skb).pid) {
 867                         UDEBUG("no config command, and wrong pid\n");
 868                         ret = -EPERM;
 869                         goto out_put;
 870                 }
 871         }
 872
 873         if (nfula[NFULA_CFG_MODE-1]) {
 874                 struct nfulnl_msg_config_mode *params;
 875                 params = NFA_DATA(nfula[NFULA_CFG_MODE-1]);
 876
 877                 nfulnl_set_mode(inst, params->copy_mode,
 878                                 ntohs(params->copy_range));
 879         }
 880
 881         if (nfula[NFULA_CFG_TIMEOUT-1]) {
 882                 u_int32_t timeout =
 883                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_TIMEOUT-1]);
 884
 885                 nfulnl_set_timeout(inst, ntohl(timeout));
 886         }
 887
 888         if (nfula[NFULA_CFG_NLBUFSIZ-1]) {
 889                 u_int32_t nlbufsiz =
 890                         *(u_int32_t *)NFA_DATA(nfula[NFULA_CFG_NLBUFSIZ-1]);
 891
 892                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 893         }
 894
 895         if (nfula[NFULA_CFG_QTHRESH-1]) {
 896                 u_int32_t qthresh =
 897                         *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_QTHRESH-1]);
 898
 899                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 900         }
 901
 902         if (nfula[NFULA_CFG_FLAGS-1]) {
 903                 u_int16_t flags =
 904                         *(u_int16_t *)NFA_DATA(nfula[NFULA_CFG_FLAGS-1]);
 905                 nfulnl_set_flags(inst, ntohl(flags));
 906         }
 907
 908 out_put:
 909         instance_put(inst);
 910         return ret;
 911 }
 912
 913 static struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 914         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 915                                     .attr_count = NFULA_MAX, },
 916         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 917                                     .attr_count = NFULA_CFG_MAX, },
 918 };
 919
 920 static struct nfnetlink_subsystem nfulnl_subsys = {
 921         .name           = "log",
 922         .subsys_id      = NFNL_SUBSYS_ULOG,
 923         .cb_count       = NFULNL_MSG_MAX,
 924         .cb             = nfulnl_cb,
 925 };
 926
 927 #ifdef CONFIG_PROC_FS
 928 struct iter_state {
 929         unsigned int bucket;
 930 };
 931
 932 static struct hlist_node *get_first(struct seq_file *seq)
 933 {
 934         struct iter_state *st = seq->private;
 935
 936         if (!st)
 937                 return NULL;
 938
 939         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 940                 if (!hlist_empty(&instance_table[st->bucket]))
 941                         return instance_table[st->bucket].first;
 942         }
 943         return NULL;
 944 }
 945
 946 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
 947 {
 948         struct iter_state *st = seq->private;
 949
 950         h = h->next;
 951         while (!h) {
 952                 if (++st->bucket >= INSTANCE_BUCKETS)
 953                         return NULL;
 954
 955                 h = instance_table[st->bucket].first;
 956         }
 957         return h;
 958 }
 959
 960 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
 961 {
 962         struct hlist_node *head;
 963         head = get_first(seq);
 964
 965         if (head)
 966                 while (pos && (head = get_next(seq, head)))
 967                         pos--;
 968         return pos ? NULL : head;
 969 }
 970
 971 static void *seq_start(struct seq_file *seq, loff_t *pos)
 972 {
 973         read_lock_bh(&instances_lock);
 974         return get_idx(seq, *pos);
 975 }
 976
 977 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 978 {
 979         (*pos)++;
 980         return get_next(s, v);
 981 }
 982
 983 static void seq_stop(struct seq_file *s, void *v)
 984 {
 985         read_unlock_bh(&instances_lock);
 986 }
 987
 988 static int seq_show(struct seq_file *s, void *v)
 989 {
 990         const struct nfulnl_instance *inst = v;
 991
 992         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 993                           inst->group_num,
 994                           inst->peer_pid, inst->qlen,
 995                           inst->copy_mode, inst->copy_range,
 996                           inst->flushtimeout, atomic_read(&inst->use));
 997 }
 998
 999 static struct seq_operations nful_seq_ops = {
1000         .start  = seq_start,
1001         .next   = seq_next,
1002         .stop   = seq_stop,
1003         .show   = seq_show,
1004 };
1005
1006 static int nful_open(struct inode *inode, struct file *file)
1007 {
1008         struct seq_file *seq;
1009         struct iter_state *is;
1010         int ret;
1011
1012         is = kzalloc(sizeof(*is), GFP_KERNEL);
1013         if (!is)
1014                 return -ENOMEM;
1015         ret = seq_open(file, &nful_seq_ops);
1016         if (ret < 0)
1017                 goto out_free;
1018         seq = file->private_data;
1019         seq->private = is;
1020         return ret;
1021 out_free:
1022         kfree(is);
1023         return ret;
1024 }
1025
1026 static struct file_operations nful_file_ops = {
1027         .owner   = THIS_MODULE,
1028         .open    = nful_open,
1029         .read    = seq_read,
1030         .llseek  = seq_lseek,
1031         .release = seq_release_private,
1032 };
1033
1034 #endif /* PROC_FS */
1035
1036 static int
1037 init_or_cleanup(int init)
1038 {
1039         int i, status = -ENOMEM;
1040 #ifdef CONFIG_PROC_FS
1041         struct proc_dir_entry *proc_nful;
1042 #endif
1043
1044         if (!init)
1045                 goto cleanup;
1046
1047         for (i = 0; i < INSTANCE_BUCKETS; i++)
1048                 INIT_HLIST_HEAD(&instance_table[i]);
1049
1050         /* it's not really all that important to have a random value, so
1051          * we can do this from the init function, even if there hasn't
1052          * been that much entropy yet */
1053         get_random_bytes(&hash_init, sizeof(hash_init));
1054
1055         netlink_register_notifier(&nfulnl_rtnl_notifier);
1056         status = nfnetlink_subsys_register(&nfulnl_subsys);
1057         if (status < 0) {
1058                 printk(KERN_ERR "log: failed to create netlink socket\n");
1059                 goto cleanup_netlink_notifier;
1060         }
1061
1062 #ifdef CONFIG_PROC_FS
1063         proc_nful = create_proc_entry("nfnetlink_log", 0440,
1064                                       proc_net_netfilter);
1065         if (!proc_nful)
1066                 goto cleanup_subsys;
1067         proc_nful->proc_fops = &nful_file_ops;
1068 #endif
1069
1070         return status;
1071
1072 cleanup:
1073         nf_log_unregister_logger(&nfulnl_logger);
1074 #ifdef CONFIG_PROC_FS
1075         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1076 cleanup_subsys:
1077 #endif
1078         nfnetlink_subsys_unregister(&nfulnl_subsys);
1079 cleanup_netlink_notifier:
1080         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1081         return status;
1082 }
1083
1084 static int __init init(void)
1085 {
1086
1087         return init_or_cleanup(1);
1088 }
1089
1090 static void __exit fini(void)
1091 {
1092         init_or_cleanup(0);
1093 }
1094
1095 MODULE_DESCRIPTION("netfilter userspace logging");
1096 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1097 MODULE_LICENSE("GPL");
1098 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1099
1100 module_init(init);
1101 module_exit(fini);