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 #include <linux/module.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/init.h>
  17 #include <linux/ip.h>
  18 #include <linux/ipv6.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/netfilter.h>
  21 #include <linux/netlink.h>
  22 #include <linux/netfilter/nfnetlink.h>
  23 #include <linux/netfilter/nfnetlink_log.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/sysctl.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/security.h>
  28 #include <linux/list.h>
  29 #include <linux/jhash.h>
  30 #include <linux/random.h>
  31 #include <linux/slab.h>
  32 #include <net/sock.h>
  33 #include <net/netfilter/nf_log.h>
  34 #include <net/netfilter/nfnetlink_log.h>
  35
  36 #include <asm/atomic.h>
  37
  38 #ifdef CONFIG_BRIDGE_NETFILTER
  39 #include "../bridge/br_private.h"
  40 #endif
  41
  42 #define NFULNL_NLBUFSIZ_DEFAULT NLMSG_GOODSIZE
  43 #define NFULNL_TIMEOUT_DEFAULT  100     /* every second */
  44 #define NFULNL_QTHRESH_DEFAULT  100     /* 100 packets */
  45 #define NFULNL_COPY_RANGE_MAX   0xFFFF  /* max packet size is limited by 16-bit struct nfattr nfa_len field */
  46
  47 #define PRINTR(x, args...)      do { if (net_ratelimit()) \
  48                                      printk(x, ## args); } while (0);
  49
  50 struct nfulnl_instance {
  51         struct hlist_node hlist;        /* global list of instances */
  52         spinlock_t lock;
  53         atomic_t use;                   /* use count */
  54
  55         unsigned int qlen;              /* number of nlmsgs in skb */
  56         struct sk_buff *skb;            /* pre-allocatd skb */
  57         struct timer_list timer;
  58         int peer_pid;                   /* PID of the peer process */
  59
  60         /* configurable parameters */
  61         unsigned int flushtimeout;      /* timeout until queue flush */
  62         unsigned int nlbufsiz;          /* netlink buffer allocation size */
  63         unsigned int qthreshold;        /* threshold of the queue */
  64         u_int32_t copy_range;
  65         u_int32_t seq;                  /* instance-local sequential counter */
  66         u_int16_t group_num;            /* number of this queue */
  67         u_int16_t flags;
  68         u_int8_t copy_mode;
  69         struct rcu_head rcu;
  70 };
  71
  72 static DEFINE_SPINLOCK(instances_lock);
  73 static atomic_t global_seq;
  74
  75 #define INSTANCE_BUCKETS        16
  76 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  77 static unsigned int hash_init;
  78
  79 static inline u_int8_t instance_hashfn(u_int16_t group_num)
  80 {
  81         return ((group_num & 0xff) % INSTANCE_BUCKETS);
  82 }
  83
  84 static struct nfulnl_instance *
  85 __instance_lookup(u_int16_t group_num)
  86 {
  87         struct hlist_head *head;
  88         struct hlist_node *pos;
  89         struct nfulnl_instance *inst;
  90
  91         head = &instance_table[instance_hashfn(group_num)];
  92         hlist_for_each_entry_rcu(inst, pos, head, hlist) {
  93                 if (inst->group_num == group_num)
  94                         return inst;
  95         }
  96         return NULL;
  97 }
  98
  99 static inline void
 100 instance_get(struct nfulnl_instance *inst)
 101 {
 102         atomic_inc(&inst->use);
 103 }
 104
 105 static struct nfulnl_instance *
 106 instance_lookup_get(u_int16_t group_num)
 107 {
 108         struct nfulnl_instance *inst;
 109
 110         rcu_read_lock_bh();
 111         inst = __instance_lookup(group_num);
 112         if (inst && !atomic_inc_not_zero(&inst->use))
 113                 inst = NULL;
 114         rcu_read_unlock_bh();
 115
 116         return inst;
 117 }
 118
 119 static void nfulnl_instance_free_rcu(struct rcu_head *head)
 120 {
 121         kfree(container_of(head, struct nfulnl_instance, rcu));
 122         module_put(THIS_MODULE);
 123 }
 124
 125 static void
 126 instance_put(struct nfulnl_instance *inst)
 127 {
 128         if (inst && atomic_dec_and_test(&inst->use))
 129                 call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 130 }
 131
 132 static void nfulnl_timer(unsigned long data);
 133
 134 static struct nfulnl_instance *
 135 instance_create(u_int16_t group_num, int pid)
 136 {
 137         struct nfulnl_instance *inst;
 138         int err;
 139
 140         spin_lock_bh(&instances_lock);
 141         if (__instance_lookup(group_num)) {
 142                 err = -EEXIST;
 143                 goto out_unlock;
 144         }
 145
 146         inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 147         if (!inst) {
 148                 err = -ENOMEM;
 149                 goto out_unlock;
 150         }
 151
 152         if (!try_module_get(THIS_MODULE)) {
 153                 kfree(inst);
 154                 err = -EAGAIN;
 155                 goto out_unlock;
 156         }
 157
 158         INIT_HLIST_NODE(&inst->hlist);
 159         spin_lock_init(&inst->lock);
 160         /* needs to be two, since we _put() after creation */
 161         atomic_set(&inst->use, 2);
 162
 163         setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 164
 165         inst->peer_pid = pid;
 166         inst->group_num = group_num;
 167
 168         inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 169         inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 170         inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 171         inst->copy_mode         = NFULNL_COPY_PACKET;
 172         inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 173
 174         hlist_add_head_rcu(&inst->hlist,
 175                        &instance_table[instance_hashfn(group_num)]);
 176
 177         spin_unlock_bh(&instances_lock);
 178
 179         return inst;
 180
 181 out_unlock:
 182         spin_unlock_bh(&instances_lock);
 183         return ERR_PTR(err);
 184 }
 185
 186 static void __nfulnl_flush(struct nfulnl_instance *inst);
 187
 188 /* called with BH disabled */
 189 static void
 190 __instance_destroy(struct nfulnl_instance *inst)
 191 {
 192         /* first pull it out of the global list */
 193         hlist_del_rcu(&inst->hlist);
 194
 195         /* then flush all pending packets from skb */
 196
 197         spin_lock(&inst->lock);
 198
 199         /* lockless readers wont be able to use us */
 200         inst->copy_mode = NFULNL_COPY_DISABLED;
 201
 202         if (inst->skb)
 203                 __nfulnl_flush(inst);
 204         spin_unlock(&inst->lock);
 205
 206         /* and finally put the refcount */
 207         instance_put(inst);
 208 }
 209
 210 static inline void
 211 instance_destroy(struct nfulnl_instance *inst)
 212 {
 213         spin_lock_bh(&instances_lock);
 214         __instance_destroy(inst);
 215         spin_unlock_bh(&instances_lock);
 216 }
 217
 218 static int
 219 nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 220                   unsigned int range)
 221 {
 222         int status = 0;
 223
 224         spin_lock_bh(&inst->lock);
 225
 226         switch (mode) {
 227         case NFULNL_COPY_NONE:
 228         case NFULNL_COPY_META:
 229                 inst->copy_mode = mode;
 230                 inst->copy_range = 0;
 231                 break;
 232
 233         case NFULNL_COPY_PACKET:
 234                 inst->copy_mode = mode;
 235                 inst->copy_range = min_t(unsigned int,
 236                                          range, NFULNL_COPY_RANGE_MAX);
 237                 break;
 238
 239         default:
 240                 status = -EINVAL;
 241                 break;
 242         }
 243
 244         spin_unlock_bh(&inst->lock);
 245
 246         return status;
 247 }
 248
 249 static int
 250 nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 251 {
 252         int status;
 253
 254         spin_lock_bh(&inst->lock);
 255         if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 256                 status = -ERANGE;
 257         else if (nlbufsiz > 131072)
 258                 status = -ERANGE;
 259         else {
 260                 inst->nlbufsiz = nlbufsiz;
 261                 status = 0;
 262         }
 263         spin_unlock_bh(&inst->lock);
 264
 265         return status;
 266 }
 267
 268 static int
 269 nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 270 {
 271         spin_lock_bh(&inst->lock);
 272         inst->flushtimeout = timeout;
 273         spin_unlock_bh(&inst->lock);
 274
 275         return 0;
 276 }
 277
 278 static int
 279 nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 280 {
 281         spin_lock_bh(&inst->lock);
 282         inst->qthreshold = qthresh;
 283         spin_unlock_bh(&inst->lock);
 284
 285         return 0;
 286 }
 287
 288 static int
 289 nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 290 {
 291         spin_lock_bh(&inst->lock);
 292         inst->flags = flags;
 293         spin_unlock_bh(&inst->lock);
 294
 295         return 0;
 296 }
 297
 298 static struct sk_buff *
 299 nfulnl_alloc_skb(unsigned int inst_size, unsigned int pkt_size)
 300 {
 301         struct sk_buff *skb;
 302         unsigned int n;
 303
 304         /* alloc skb which should be big enough for a whole multipart
 305          * message.  WARNING: has to be <= 128k due to slab restrictions */
 306
 307         n = max(inst_size, pkt_size);
 308         skb = alloc_skb(n, GFP_ATOMIC);
 309         if (!skb) {
 310                 pr_notice("nfnetlink_log: can't alloc whole buffer (%u bytes)\n",
 311                         inst_size);
 312
 313                 if (n > pkt_size) {
 314                         /* try to allocate only as much as we need for current
 315                          * packet */
 316
 317                         skb = alloc_skb(pkt_size, GFP_ATOMIC);
 318                         if (!skb)
 319                                 pr_err("nfnetlink_log: can't even alloc %u "
 320                                        "bytes\n", pkt_size);
 321                 }
 322         }
 323
 324         return skb;
 325 }
 326
 327 static int
 328 __nfulnl_send(struct nfulnl_instance *inst)
 329 {
 330         int status = -1;
 331
 332         if (inst->qlen > 1)
 333                 NLMSG_PUT(inst->skb, 0, 0,
 334                           NLMSG_DONE,
 335                           sizeof(struct nfgenmsg));
 336
 337         status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_pid,
 338                                    MSG_DONTWAIT);
 339
 340         inst->qlen = 0;
 341         inst->skb = NULL;
 342
 343 nlmsg_failure:
 344         return status;
 345 }
 346
 347 static void
 348 __nfulnl_flush(struct nfulnl_instance *inst)
 349 {
 350         /* timer holds a reference */
 351         if (del_timer(&inst->timer))
 352                 instance_put(inst);
 353         if (inst->skb)
 354                 __nfulnl_send(inst);
 355 }
 356
 357 static void
 358 nfulnl_timer(unsigned long data)
 359 {
 360         struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 361
 362         spin_lock_bh(&inst->lock);
 363         if (inst->skb)
 364                 __nfulnl_send(inst);
 365         spin_unlock_bh(&inst->lock);
 366         instance_put(inst);
 367 }
 368
 369 /* This is an inline function, we don't really care about a long
 370  * list of arguments */
 371 static inline int
 372 __build_packet_message(struct nfulnl_instance *inst,
 373                         const struct sk_buff *skb,
 374                         unsigned int data_len,
 375                         u_int8_t pf,
 376                         unsigned int hooknum,
 377                         const struct net_device *indev,
 378                         const struct net_device *outdev,
 379                         const struct nf_loginfo *li,
 380                         const char *prefix, unsigned int plen)
 381 {
 382         struct nfulnl_msg_packet_hdr pmsg;
 383         struct nlmsghdr *nlh;
 384         struct nfgenmsg *nfmsg;
 385         __be32 tmp_uint;
 386         sk_buff_data_t old_tail = inst->skb->tail;
 387
 388         nlh = NLMSG_PUT(inst->skb, 0, 0,
 389                         NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 390                         sizeof(struct nfgenmsg));
 391         nfmsg = NLMSG_DATA(nlh);
 392         nfmsg->nfgen_family = pf;
 393         nfmsg->version = NFNETLINK_V0;
 394         nfmsg->res_id = htons(inst->group_num);
 395
 396         pmsg.hw_protocol        = skb->protocol;
 397         pmsg.hook               = hooknum;
 398
 399         NLA_PUT(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg);
 400
 401         if (prefix)
 402                 NLA_PUT(inst->skb, NFULA_PREFIX, plen, prefix);
 403
 404         if (indev) {
 405 #ifndef CONFIG_BRIDGE_NETFILTER
 406                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 407                              htonl(indev->ifindex));
 408 #else
 409                 if (pf == PF_BRIDGE) {
 410                         /* Case 1: outdev is physical input device, we need to
 411                          * look for bridge group (when called from
 412                          * netfilter_bridge) */
 413                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 414                                      htonl(indev->ifindex));
 415                         /* this is the bridge group "brX" */
 416                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 417                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 418                                      htonl(br_port_get_rcu(indev)->br->dev->ifindex));
 419                 } else {
 420                         /* Case 2: indev is bridge group, we need to look for
 421                          * physical device (when called from ipv4) */
 422                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_INDEV,
 423                                      htonl(indev->ifindex));
 424                         if (skb->nf_bridge && skb->nf_bridge->physindev)
 425                                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 426                                              htonl(skb->nf_bridge->physindev->ifindex));
 427                 }
 428 #endif
 429         }
 430
 431         if (outdev) {
 432                 tmp_uint = htonl(outdev->ifindex);
 433 #ifndef CONFIG_BRIDGE_NETFILTER
 434                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 435                              htonl(outdev->ifindex));
 436 #else
 437                 if (pf == PF_BRIDGE) {
 438                         /* Case 1: outdev is physical output device, we need to
 439                          * look for bridge group (when called from
 440                          * netfilter_bridge) */
 441                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 442                                      htonl(outdev->ifindex));
 443                         /* this is the bridge group "brX" */
 444                         /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 445                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 446                                      htonl(br_port_get_rcu(outdev)->br->dev->ifindex));
 447                 } else {
 448                         /* Case 2: indev is a bridge group, we need to look
 449                          * for physical device (when called from ipv4) */
 450                         NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_OUTDEV,
 451                                      htonl(outdev->ifindex));
 452                         if (skb->nf_bridge && skb->nf_bridge->physoutdev)
 453                                 NLA_PUT_BE32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 454                                              htonl(skb->nf_bridge->physoutdev->ifindex));
 455                 }
 456 #endif
 457         }
 458
 459         if (skb->mark)
 460                 NLA_PUT_BE32(inst->skb, NFULA_MARK, htonl(skb->mark));
 461
 462         if (indev && skb->dev) {
 463                 struct nfulnl_msg_packet_hw phw;
 464                 int len = dev_parse_header(skb, phw.hw_addr);
 465                 if (len > 0) {
 466                         phw.hw_addrlen = htons(len);
 467                         NLA_PUT(inst->skb, NFULA_HWADDR, sizeof(phw), &phw);
 468                 }
 469         }
 470
 471         if (indev && skb_mac_header_was_set(skb)) {
 472                 NLA_PUT_BE16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type));
 473                 NLA_PUT_BE16(inst->skb, NFULA_HWLEN,
 474                              htons(skb->dev->hard_header_len));
 475                 NLA_PUT(inst->skb, NFULA_HWHEADER, skb->dev->hard_header_len,
 476                         skb_mac_header(skb));
 477         }
 478
 479         if (skb->tstamp.tv64) {
 480                 struct nfulnl_msg_packet_timestamp ts;
 481                 struct timeval tv = ktime_to_timeval(skb->tstamp);
 482                 ts.sec = cpu_to_be64(tv.tv_sec);
 483                 ts.usec = cpu_to_be64(tv.tv_usec);
 484
 485                 NLA_PUT(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts);
 486         }
 487
 488         /* UID */
 489         if (skb->sk) {
 490                 read_lock_bh(&skb->sk->sk_callback_lock);
 491                 if (skb->sk->sk_socket && skb->sk->sk_socket->file) {
 492                         struct file *file = skb->sk->sk_socket->file;
 493                         __be32 uid = htonl(file->f_cred->fsuid);
 494                         __be32 gid = htonl(file->f_cred->fsgid);
 495                         /* need to unlock here since NLA_PUT may goto */
 496                         read_unlock_bh(&skb->sk->sk_callback_lock);
 497                         NLA_PUT_BE32(inst->skb, NFULA_UID, uid);
 498                         NLA_PUT_BE32(inst->skb, NFULA_GID, gid);
 499                 } else
 500                         read_unlock_bh(&skb->sk->sk_callback_lock);
 501         }
 502
 503         /* local sequence number */
 504         if (inst->flags & NFULNL_CFG_F_SEQ)
 505                 NLA_PUT_BE32(inst->skb, NFULA_SEQ, htonl(inst->seq++));
 506
 507         /* global sequence number */
 508         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 509                 NLA_PUT_BE32(inst->skb, NFULA_SEQ_GLOBAL,
 510                              htonl(atomic_inc_return(&global_seq)));
 511
 512         if (data_len) {
 513                 struct nlattr *nla;
 514                 int size = nla_attr_size(data_len);
 515
 516                 if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
 517                         printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 518                         goto nlmsg_failure;
 519                 }
 520
 521                 nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 522                 nla->nla_type = NFULA_PAYLOAD;
 523                 nla->nla_len = size;
 524
 525                 if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 526                         BUG();
 527         }
 528
 529         nlh->nlmsg_len = inst->skb->tail - old_tail;
 530         return 0;
 531
 532 nlmsg_failure:
 533 nla_put_failure:
 534         PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 535         return -1;
 536 }
 537
 538 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 539
 540 static struct nf_loginfo default_loginfo = {
 541         .type =         NF_LOG_TYPE_ULOG,
 542         .u = {
 543                 .ulog = {
 544                         .copy_len       = 0xffff,
 545                         .group          = 0,
 546                         .qthreshold     = 1,
 547                 },
 548         },
 549 };
 550
 551 /* log handler for internal netfilter logging api */
 552 void
 553 nfulnl_log_packet(u_int8_t pf,
 554                   unsigned int hooknum,
 555                   const struct sk_buff *skb,
 556                   const struct net_device *in,
 557                   const struct net_device *out,
 558                   const struct nf_loginfo *li_user,
 559                   const char *prefix)
 560 {
 561         unsigned int size, data_len;
 562         struct nfulnl_instance *inst;
 563         const struct nf_loginfo *li;
 564         unsigned int qthreshold;
 565         unsigned int plen;
 566
 567         if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 568                 li = li_user;
 569         else
 570                 li = &default_loginfo;
 571
 572         inst = instance_lookup_get(li->u.ulog.group);
 573         if (!inst)
 574                 return;
 575
 576         plen = 0;
 577         if (prefix)
 578                 plen = strlen(prefix) + 1;
 579
 580         /* FIXME: do we want to make the size calculation conditional based on
 581          * what is actually present?  way more branches and checks, but more
 582          * memory efficient... */
 583         size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 584                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 585                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 586                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 587 #ifdef CONFIG_BRIDGE_NETFILTER
 588                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 589                 + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 590 #endif
 591                 + nla_total_size(sizeof(u_int32_t))     /* mark */
 592                 + nla_total_size(sizeof(u_int32_t))     /* uid */
 593                 + nla_total_size(sizeof(u_int32_t))     /* gid */
 594                 + nla_total_size(plen)                  /* prefix */
 595                 + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 596                 + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
 597
 598         if (in && skb_mac_header_was_set(skb)) {
 599                 size +=   nla_total_size(skb->dev->hard_header_len)
 600                         + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 601                         + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 602         }
 603
 604         spin_lock_bh(&inst->lock);
 605
 606         if (inst->flags & NFULNL_CFG_F_SEQ)
 607                 size += nla_total_size(sizeof(u_int32_t));
 608         if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 609                 size += nla_total_size(sizeof(u_int32_t));
 610
 611         qthreshold = inst->qthreshold;
 612         /* per-rule qthreshold overrides per-instance */
 613         if (li->u.ulog.qthreshold)
 614                 if (qthreshold > li->u.ulog.qthreshold)
 615                         qthreshold = li->u.ulog.qthreshold;
 616
 617
 618         switch (inst->copy_mode) {
 619         case NFULNL_COPY_META:
 620         case NFULNL_COPY_NONE:
 621                 data_len = 0;
 622                 break;
 623
 624         case NFULNL_COPY_PACKET:
 625                 if (inst->copy_range == 0
 626                     || inst->copy_range > skb->len)
 627                         data_len = skb->len;
 628                 else
 629                         data_len = inst->copy_range;
 630
 631                 size += nla_total_size(data_len);
 632                 break;
 633
 634         case NFULNL_COPY_DISABLED:
 635         default:
 636                 goto unlock_and_release;
 637         }
 638
 639         if (inst->skb &&
 640             size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
 641                 /* either the queue len is too high or we don't have
 642                  * enough room in the skb left. flush to userspace. */
 643                 __nfulnl_flush(inst);
 644         }
 645
 646         if (!inst->skb) {
 647                 inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
 648                 if (!inst->skb)
 649                         goto alloc_failure;
 650         }
 651
 652         inst->qlen++;
 653
 654         __build_packet_message(inst, skb, data_len, pf,
 655                                 hooknum, in, out, li, prefix, plen);
 656
 657         if (inst->qlen >= qthreshold)
 658                 __nfulnl_flush(inst);
 659         /* timer_pending always called within inst->lock, so there
 660          * is no chance of a race here */
 661         else if (!timer_pending(&inst->timer)) {
 662                 instance_get(inst);
 663                 inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 664                 add_timer(&inst->timer);
 665         }
 666
 667 unlock_and_release:
 668         spin_unlock_bh(&inst->lock);
 669         instance_put(inst);
 670         return;
 671
 672 alloc_failure:
 673         /* FIXME: statistics */
 674         goto unlock_and_release;
 675 }
 676 EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 677
 678 static int
 679 nfulnl_rcv_nl_event(struct notifier_block *this,
 680                    unsigned long event, void *ptr)
 681 {
 682         struct netlink_notify *n = ptr;
 683
 684         if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 685                 int i;
 686
 687                 /* destroy all instances for this pid */
 688                 spin_lock_bh(&instances_lock);
 689                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 690                         struct hlist_node *tmp, *t2;
 691                         struct nfulnl_instance *inst;
 692                         struct hlist_head *head = &instance_table[i];
 693
 694                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 695                                 if ((net_eq(n->net, &init_net)) &&
 696                                     (n->pid == inst->peer_pid))
 697                                         __instance_destroy(inst);
 698                         }
 699                 }
 700                 spin_unlock_bh(&instances_lock);
 701         }
 702         return NOTIFY_DONE;
 703 }
 704
 705 static struct notifier_block nfulnl_rtnl_notifier = {
 706         .notifier_call  = nfulnl_rcv_nl_event,
 707 };
 708
 709 static int
 710 nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 711                    const struct nlmsghdr *nlh,
 712                    const struct nlattr * const nfqa[])
 713 {
 714         return -ENOTSUPP;
 715 }
 716
 717 static struct nf_logger nfulnl_logger __read_mostly = {
 718         .name   = "nfnetlink_log",
 719         .logfn  = &nfulnl_log_packet,
 720         .me     = THIS_MODULE,
 721 };
 722
 723 static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 724         [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 725         [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 726         [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 727         [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 728         [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 729         [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 730 };
 731
 732 static int
 733 nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 734                    const struct nlmsghdr *nlh,
 735                    const struct nlattr * const nfula[])
 736 {
 737         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 738         u_int16_t group_num = ntohs(nfmsg->res_id);
 739         struct nfulnl_instance *inst;
 740         struct nfulnl_msg_config_cmd *cmd = NULL;
 741         int ret = 0;
 742
 743         if (nfula[NFULA_CFG_CMD]) {
 744                 u_int8_t pf = nfmsg->nfgen_family;
 745                 cmd = nla_data(nfula[NFULA_CFG_CMD]);
 746
 747                 /* Commands without queue context */
 748                 switch (cmd->command) {
 749                 case NFULNL_CFG_CMD_PF_BIND:
 750                         return nf_log_bind_pf(pf, &nfulnl_logger);
 751                 case NFULNL_CFG_CMD_PF_UNBIND:
 752                         nf_log_unbind_pf(pf);
 753                         return 0;
 754                 }
 755         }
 756
 757         inst = instance_lookup_get(group_num);
 758         if (inst && inst->peer_pid != NETLINK_CB(skb).pid) {
 759                 ret = -EPERM;
 760                 goto out_put;
 761         }
 762
 763         if (cmd != NULL) {
 764                 switch (cmd->command) {
 765                 case NFULNL_CFG_CMD_BIND:
 766                         if (inst) {
 767                                 ret = -EBUSY;
 768                                 goto out_put;
 769                         }
 770
 771                         inst = instance_create(group_num,
 772                                                NETLINK_CB(skb).pid);
 773                         if (IS_ERR(inst)) {
 774                                 ret = PTR_ERR(inst);
 775                                 goto out;
 776                         }
 777                         break;
 778                 case NFULNL_CFG_CMD_UNBIND:
 779                         if (!inst) {
 780                                 ret = -ENODEV;
 781                                 goto out;
 782                         }
 783
 784                         instance_destroy(inst);
 785                         goto out_put;
 786                 default:
 787                         ret = -ENOTSUPP;
 788                         break;
 789                 }
 790         }
 791
 792         if (nfula[NFULA_CFG_MODE]) {
 793                 struct nfulnl_msg_config_mode *params;
 794                 params = nla_data(nfula[NFULA_CFG_MODE]);
 795
 796                 if (!inst) {
 797                         ret = -ENODEV;
 798                         goto out;
 799                 }
 800                 nfulnl_set_mode(inst, params->copy_mode,
 801                                 ntohl(params->copy_range));
 802         }
 803
 804         if (nfula[NFULA_CFG_TIMEOUT]) {
 805                 __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 806
 807                 if (!inst) {
 808                         ret = -ENODEV;
 809                         goto out;
 810                 }
 811                 nfulnl_set_timeout(inst, ntohl(timeout));
 812         }
 813
 814         if (nfula[NFULA_CFG_NLBUFSIZ]) {
 815                 __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 816
 817                 if (!inst) {
 818                         ret = -ENODEV;
 819                         goto out;
 820                 }
 821                 nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 822         }
 823
 824         if (nfula[NFULA_CFG_QTHRESH]) {
 825                 __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 826
 827                 if (!inst) {
 828                         ret = -ENODEV;
 829                         goto out;
 830                 }
 831                 nfulnl_set_qthresh(inst, ntohl(qthresh));
 832         }
 833
 834         if (nfula[NFULA_CFG_FLAGS]) {
 835                 __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 836
 837                 if (!inst) {
 838                         ret = -ENODEV;
 839                         goto out;
 840                 }
 841                 nfulnl_set_flags(inst, ntohs(flags));
 842         }
 843
 844 out_put:
 845         instance_put(inst);
 846 out:
 847         return ret;
 848 }
 849
 850 static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 851         [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 852                                     .attr_count = NFULA_MAX, },
 853         [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 854                                     .attr_count = NFULA_CFG_MAX,
 855                                     .policy = nfula_cfg_policy },
 856 };
 857
 858 static const struct nfnetlink_subsystem nfulnl_subsys = {
 859         .name           = "log",
 860         .subsys_id      = NFNL_SUBSYS_ULOG,
 861         .cb_count       = NFULNL_MSG_MAX,
 862         .cb             = nfulnl_cb,
 863 };
 864
 865 #ifdef CONFIG_PROC_FS
 866 struct iter_state {
 867         unsigned int bucket;
 868 };
 869
 870 static struct hlist_node *get_first(struct iter_state *st)
 871 {
 872         if (!st)
 873                 return NULL;
 874
 875         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 876                 if (!hlist_empty(&instance_table[st->bucket]))
 877                         return rcu_dereference_bh(instance_table[st->bucket].first);
 878         }
 879         return NULL;
 880 }
 881
 882 static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
 883 {
 884         h = rcu_dereference_bh(h->next);
 885         while (!h) {
 886                 if (++st->bucket >= INSTANCE_BUCKETS)
 887                         return NULL;
 888
 889                 h = rcu_dereference_bh(instance_table[st->bucket].first);
 890         }
 891         return h;
 892 }
 893
 894 static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
 895 {
 896         struct hlist_node *head;
 897         head = get_first(st);
 898
 899         if (head)
 900                 while (pos && (head = get_next(st, head)))
 901                         pos--;
 902         return pos ? NULL : head;
 903 }
 904
 905 static void *seq_start(struct seq_file *seq, loff_t *pos)
 906         __acquires(rcu_bh)
 907 {
 908         rcu_read_lock_bh();
 909         return get_idx(seq->private, *pos);
 910 }
 911
 912 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 913 {
 914         (*pos)++;
 915         return get_next(s->private, v);
 916 }
 917
 918 static void seq_stop(struct seq_file *s, void *v)
 919         __releases(rcu_bh)
 920 {
 921         rcu_read_unlock_bh();
 922 }
 923
 924 static int seq_show(struct seq_file *s, void *v)
 925 {
 926         const struct nfulnl_instance *inst = v;
 927
 928         return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 929                           inst->group_num,
 930                           inst->peer_pid, inst->qlen,
 931                           inst->copy_mode, inst->copy_range,
 932                           inst->flushtimeout, atomic_read(&inst->use));
 933 }
 934
 935 static const struct seq_operations nful_seq_ops = {
 936         .start  = seq_start,
 937         .next   = seq_next,
 938         .stop   = seq_stop,
 939         .show   = seq_show,
 940 };
 941
 942 static int nful_open(struct inode *inode, struct file *file)
 943 {
 944         return seq_open_private(file, &nful_seq_ops,
 945                         sizeof(struct iter_state));
 946 }
 947
 948 static const struct file_operations nful_file_ops = {
 949         .owner   = THIS_MODULE,
 950         .open    = nful_open,
 951         .read    = seq_read,
 952         .llseek  = seq_lseek,
 953         .release = seq_release_private,
 954 };
 955
 956 #endif /* PROC_FS */
 957
 958 static int __init nfnetlink_log_init(void)
 959 {
 960         int i, status = -ENOMEM;
 961
 962         for (i = 0; i < INSTANCE_BUCKETS; i++)
 963                 INIT_HLIST_HEAD(&instance_table[i]);
 964
 965         /* it's not really all that important to have a random value, so
 966          * we can do this from the init function, even if there hasn't
 967          * been that much entropy yet */
 968         get_random_bytes(&hash_init, sizeof(hash_init));
 969
 970         netlink_register_notifier(&nfulnl_rtnl_notifier);
 971         status = nfnetlink_subsys_register(&nfulnl_subsys);
 972         if (status < 0) {
 973                 printk(KERN_ERR "log: failed to create netlink socket\n");
 974                 goto cleanup_netlink_notifier;
 975         }
 976
 977         status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
 978         if (status < 0) {
 979                 printk(KERN_ERR "log: failed to register logger\n");
 980                 goto cleanup_subsys;
 981         }
 982
 983 #ifdef CONFIG_PROC_FS
 984         if (!proc_create("nfnetlink_log", 0440,
 985                          proc_net_netfilter, &nful_file_ops))
 986                 goto cleanup_logger;
 987 #endif
 988         return status;
 989
 990 #ifdef CONFIG_PROC_FS
 991 cleanup_logger:
 992         nf_log_unregister(&nfulnl_logger);
 993 #endif
 994 cleanup_subsys:
 995         nfnetlink_subsys_unregister(&nfulnl_subsys);
 996 cleanup_netlink_notifier:
 997         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
 998         return status;
 999 }
1000
1001 static void __exit nfnetlink_log_fini(void)
1002 {
1003         nf_log_unregister(&nfulnl_logger);
1004 #ifdef CONFIG_PROC_FS
1005         remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1006 #endif
1007         nfnetlink_subsys_unregister(&nfulnl_subsys);
1008         netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1009 }
1010
1011 MODULE_DESCRIPTION("netfilter userspace logging");
1012 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1013 MODULE_LICENSE("GPL");
1014 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1015
1016 module_init(nfnetlink_log_init);
1017 module_exit(nfnetlink_log_fini);