net/netfilter/nfnetlink_queue.c

   1 /*
   2  * This is a module which is used for queueing packets and communicating with
   3  * userspace via nfetlink.
   4  *
   5  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   6  *
   7  * Based on the old ipv4-only ip_queue.c:
   8  * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
   9  * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  */
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/init.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/notifier.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/netfilter.h>
  23 #include <linux/proc_fs.h>
  24 #include <linux/netfilter_ipv4.h>
  25 #include <linux/netfilter_ipv6.h>
  26 #include <linux/netfilter/nfnetlink.h>
  27 #include <linux/netfilter/nfnetlink_queue.h>
  28 #include <linux/list.h>
  29 #include <net/sock.h>
  30
  31 #include <asm/atomic.h>
  32
  33 #ifdef CONFIG_BRIDGE_NETFILTER
  34 #include "../bridge/br_private.h"
  35 #endif
  36
  37 #define NFQNL_QMAX_DEFAULT 1024
  38
  39 #if 0
  40 #define QDEBUG(x, args ...)     printk(KERN_DEBUG "%s(%d):%s(): " x,       \
  41                                         __FILE__, __LINE__, __FUNCTION__,  \
  42                                         ## args)
  43 #else
  44 #define QDEBUG(x, ...)
  45 #endif
  46
  47 struct nfqnl_queue_entry {
  48         struct list_head list;
  49         struct nf_info *info;
  50         struct sk_buff *skb;
  51         unsigned int id;
  52 };
  53
  54 struct nfqnl_instance {
  55         struct hlist_node hlist;                /* global list of queues */
  56         atomic_t use;
  57
  58         int peer_pid;
  59         unsigned int queue_maxlen;
  60         unsigned int copy_range;
  61         unsigned int queue_total;
  62         unsigned int queue_dropped;
  63         unsigned int queue_user_dropped;
  64
  65         atomic_t id_sequence;                   /* 'sequence' of pkt ids */
  66
  67         u_int16_t queue_num;                    /* number of this queue */
  68         u_int8_t copy_mode;
  69
  70         spinlock_t lock;
  71
  72         struct list_head queue_list;            /* packets in queue */
  73 };
  74
  75 typedef int (*nfqnl_cmpfn)(struct nfqnl_queue_entry *, unsigned long);
  76
  77 static DEFINE_RWLOCK(instances_lock);
  78
  79 #define INSTANCE_BUCKETS        16
  80 static struct hlist_head instance_table[INSTANCE_BUCKETS];
  81
  82 static inline u_int8_t instance_hashfn(u_int16_t queue_num)
  83 {
  84         return ((queue_num >> 8) | queue_num) % INSTANCE_BUCKETS;
  85 }
  86
  87 static struct nfqnl_instance *
  88 __instance_lookup(u_int16_t queue_num)
  89 {
  90         struct hlist_head *head;
  91         struct hlist_node *pos;
  92         struct nfqnl_instance *inst;
  93
  94         head = &instance_table[instance_hashfn(queue_num)];
  95         hlist_for_each_entry(inst, pos, head, hlist) {
  96                 if (inst->queue_num == queue_num)
  97                         return inst;
  98         }
  99         return NULL;
 100 }
 101
 102 static struct nfqnl_instance *
 103 instance_lookup_get(u_int16_t queue_num)
 104 {
 105         struct nfqnl_instance *inst;
 106
 107         read_lock_bh(&instances_lock);
 108         inst = __instance_lookup(queue_num);
 109         if (inst)
 110                 atomic_inc(&inst->use);
 111         read_unlock_bh(&instances_lock);
 112
 113         return inst;
 114 }
 115
 116 static void
 117 instance_put(struct nfqnl_instance *inst)
 118 {
 119         if (inst && atomic_dec_and_test(&inst->use)) {
 120                 QDEBUG("kfree(inst=%p)\n", inst);
 121                 kfree(inst);
 122         }
 123 }
 124
 125 static struct nfqnl_instance *
 126 instance_create(u_int16_t queue_num, int pid)
 127 {
 128         struct nfqnl_instance *inst;
 129
 130         QDEBUG("entering for queue_num=%u, pid=%d\n", queue_num, pid);
 131
 132         write_lock_bh(&instances_lock);
 133         if (__instance_lookup(queue_num)) {
 134                 inst = NULL;
 135                 QDEBUG("aborting, instance already exists\n");
 136                 goto out_unlock;
 137         }
 138
 139         inst = kmalloc(sizeof(*inst), GFP_ATOMIC);
 140         if (!inst)
 141                 goto out_unlock;
 142
 143         memset(inst, 0, sizeof(*inst));
 144         inst->queue_num = queue_num;
 145         inst->peer_pid = pid;
 146         inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
 147         inst->copy_range = 0xfffff;
 148         inst->copy_mode = NFQNL_COPY_NONE;
 149         atomic_set(&inst->id_sequence, 0);
 150         /* needs to be two, since we _put() after creation */
 151         atomic_set(&inst->use, 2);
 152         inst->lock = SPIN_LOCK_UNLOCKED;
 153         INIT_LIST_HEAD(&inst->queue_list);
 154
 155         if (!try_module_get(THIS_MODULE))
 156                 goto out_free;
 157
 158         hlist_add_head(&inst->hlist,
 159                        &instance_table[instance_hashfn(queue_num)]);
 160
 161         write_unlock_bh(&instances_lock);
 162
 163         QDEBUG("successfully created new instance\n");
 164
 165         return inst;
 166
 167 out_free:
 168         kfree(inst);
 169 out_unlock:
 170         write_unlock_bh(&instances_lock);
 171         return NULL;
 172 }
 173
 174 static void nfqnl_flush(struct nfqnl_instance *queue, int verdict);
 175
 176 static void
 177 _instance_destroy2(struct nfqnl_instance *inst, int lock)
 178 {
 179         /* first pull it out of the global list */
 180         if (lock)
 181                 write_lock_bh(&instances_lock);
 182
 183         QDEBUG("removing instance %p (queuenum=%u) from hash\n",
 184                 inst, inst->queue_num);
 185         hlist_del(&inst->hlist);
 186
 187         if (lock)
 188                 write_unlock_bh(&instances_lock);
 189
 190         /* then flush all pending skbs from the queue */
 191         nfqnl_flush(inst, NF_DROP);
 192
 193         /* and finally put the refcount */
 194         instance_put(inst);
 195
 196         module_put(THIS_MODULE);
 197 }
 198
 199 static inline void
 200 __instance_destroy(struct nfqnl_instance *inst)
 201 {
 202         _instance_destroy2(inst, 0);
 203 }
 204
 205 static inline void
 206 instance_destroy(struct nfqnl_instance *inst)
 207 {
 208         _instance_destroy2(inst, 1);
 209 }
 210
 211
 212
 213 static void
 214 issue_verdict(struct nfqnl_queue_entry *entry, int verdict)
 215 {
 216         QDEBUG("entering for entry %p, verdict %u\n", entry, verdict);
 217
 218         /* TCP input path (and probably other bits) assume to be called
 219          * from softirq context, not from syscall, like issue_verdict is
 220          * called.  TCP input path deadlocks with locks taken from timer
 221          * softirq, e.g.  We therefore emulate this by local_bh_disable() */
 222
 223         local_bh_disable();
 224         nf_reinject(entry->skb, entry->info, verdict);
 225         local_bh_enable();
 226
 227         kfree(entry);
 228 }
 229
 230 static inline void
 231 __enqueue_entry(struct nfqnl_instance *queue,
 232                       struct nfqnl_queue_entry *entry)
 233 {
 234        list_add(&entry->list, &queue->queue_list);
 235        queue->queue_total++;
 236 }
 237
 238 /*
 239  * Find and return a queued entry matched by cmpfn, or return the last
 240  * entry if cmpfn is NULL.
 241  */
 242 static inline struct nfqnl_queue_entry *
 243 __find_entry(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn,
 244                    unsigned long data)
 245 {
 246         struct list_head *p;
 247
 248         list_for_each_prev(p, &queue->queue_list) {
 249                 struct nfqnl_queue_entry *entry = (struct nfqnl_queue_entry *)p;
 250
 251                 if (!cmpfn || cmpfn(entry, data))
 252                         return entry;
 253         }
 254         return NULL;
 255 }
 256
 257 static inline void
 258 __dequeue_entry(struct nfqnl_instance *q, struct nfqnl_queue_entry *entry)
 259 {
 260         list_del(&entry->list);
 261         q->queue_total--;
 262 }
 263
 264 static inline struct nfqnl_queue_entry *
 265 __find_dequeue_entry(struct nfqnl_instance *queue,
 266                      nfqnl_cmpfn cmpfn, unsigned long data)
 267 {
 268         struct nfqnl_queue_entry *entry;
 269
 270         entry = __find_entry(queue, cmpfn, data);
 271         if (entry == NULL)
 272                 return NULL;
 273
 274         __dequeue_entry(queue, entry);
 275         return entry;
 276 }
 277
 278
 279 static inline void
 280 __nfqnl_flush(struct nfqnl_instance *queue, int verdict)
 281 {
 282         struct nfqnl_queue_entry *entry;
 283
 284         while ((entry = __find_dequeue_entry(queue, NULL, 0)))
 285                 issue_verdict(entry, verdict);
 286 }
 287
 288 static inline int
 289 __nfqnl_set_mode(struct nfqnl_instance *queue,
 290                  unsigned char mode, unsigned int range)
 291 {
 292         int status = 0;
 293
 294         switch (mode) {
 295         case NFQNL_COPY_NONE:
 296         case NFQNL_COPY_META:
 297                 queue->copy_mode = mode;
 298                 queue->copy_range = 0;
 299                 break;
 300
 301         case NFQNL_COPY_PACKET:
 302                 queue->copy_mode = mode;
 303                 /* we're using struct nfattr which has 16bit nfa_len */
 304                 if (range > 0xffff)
 305                         queue->copy_range = 0xffff;
 306                 else
 307                         queue->copy_range = range;
 308                 break;
 309
 310         default:
 311                 status = -EINVAL;
 312
 313         }
 314         return status;
 315 }
 316
 317 static struct nfqnl_queue_entry *
 318 find_dequeue_entry(struct nfqnl_instance *queue,
 319                          nfqnl_cmpfn cmpfn, unsigned long data)
 320 {
 321         struct nfqnl_queue_entry *entry;
 322
 323         spin_lock_bh(&queue->lock);
 324         entry = __find_dequeue_entry(queue, cmpfn, data);
 325         spin_unlock_bh(&queue->lock);
 326
 327         return entry;
 328 }
 329
 330 static void
 331 nfqnl_flush(struct nfqnl_instance *queue, int verdict)
 332 {
 333         spin_lock_bh(&queue->lock);
 334         __nfqnl_flush(queue, verdict);
 335         spin_unlock_bh(&queue->lock);
 336 }
 337
 338 static struct sk_buff *
 339 nfqnl_build_packet_message(struct nfqnl_instance *queue,
 340                            struct nfqnl_queue_entry *entry, int *errp)
 341 {
 342         unsigned char *old_tail;
 343         size_t size;
 344         size_t data_len = 0;
 345         struct sk_buff *skb;
 346         struct nfqnl_msg_packet_hdr pmsg;
 347         struct nlmsghdr *nlh;
 348         struct nfgenmsg *nfmsg;
 349         unsigned int tmp_uint;
 350
 351         QDEBUG("entered\n");
 352
 353         /* all macros expand to constant values at compile time */
 354         size =    NLMSG_SPACE(sizeof(struct nfqnl_msg_packet_hdr))
 355                 + NLMSG_SPACE(sizeof(u_int32_t))        /* ifindex */
 356                 + NLMSG_SPACE(sizeof(u_int32_t))        /* ifindex */
 357 #ifdef CONFIG_BRIDGE_NETFILTER
 358                 + NLMSG_SPACE(sizeof(u_int32_t))        /* ifindex */
 359                 + NLMSG_SPACE(sizeof(u_int32_t))        /* ifindex */
 360 #endif
 361                 + NLMSG_SPACE(sizeof(u_int32_t))        /* mark */
 362                 + NLMSG_SPACE(sizeof(struct nfqnl_msg_packet_hw))
 363                 + NLMSG_SPACE(sizeof(struct nfqnl_msg_packet_timestamp));
 364
 365         spin_lock_bh(&queue->lock);
 366
 367         switch (queue->copy_mode) {
 368         case NFQNL_COPY_META:
 369         case NFQNL_COPY_NONE:
 370                 data_len = 0;
 371                 break;
 372
 373         case NFQNL_COPY_PACKET:
 374                 if (queue->copy_range == 0
 375                     || queue->copy_range > entry->skb->len)
 376                         data_len = entry->skb->len;
 377                 else
 378                         data_len = queue->copy_range;
 379
 380                 size += NLMSG_SPACE(data_len);
 381                 break;
 382
 383         default:
 384                 *errp = -EINVAL;
 385                 spin_unlock_bh(&queue->lock);
 386                 return NULL;
 387         }
 388
 389         spin_unlock_bh(&queue->lock);
 390
 391         skb = alloc_skb(size, GFP_ATOMIC);
 392         if (!skb)
 393                 goto nlmsg_failure;
 394
 395         old_tail= skb->tail;
 396         nlh = NLMSG_PUT(skb, 0, 0,
 397                         NFNL_SUBSYS_QUEUE << 8 | NFQNL_MSG_PACKET,
 398                         sizeof(struct nfgenmsg));
 399         nfmsg = NLMSG_DATA(nlh);
 400         nfmsg->nfgen_family = entry->info->pf;
 401         nfmsg->version = NFNETLINK_V0;
 402         nfmsg->res_id = htons(queue->queue_num);
 403
 404         pmsg.packet_id          = htonl(entry->id);
 405         pmsg.hw_protocol        = htons(entry->skb->protocol);
 406         pmsg.hook               = entry->info->hook;
 407
 408         NFA_PUT(skb, NFQA_PACKET_HDR, sizeof(pmsg), &pmsg);
 409
 410         if (entry->info->indev) {
 411                 tmp_uint = htonl(entry->info->indev->ifindex);
 412 #ifndef CONFIG_BRIDGE_NETFILTER
 413                 NFA_PUT(skb, NFQA_IFINDEX_INDEV, sizeof(tmp_uint), &tmp_uint);
 414 #else
 415                 if (entry->info->pf == PF_BRIDGE) {
 416                         /* Case 1: indev is physical input device, we need to
 417                          * look for bridge group (when called from
 418                          * netfilter_bridge) */
 419                         NFA_PUT(skb, NFQA_IFINDEX_PHYSINDEV, sizeof(tmp_uint),
 420                                 &tmp_uint);
 421                         /* this is the bridge group "brX" */
 422                         tmp_uint = htonl(entry->info->indev->br_port->br->dev->ifindex);
 423                         NFA_PUT(skb, NFQA_IFINDEX_INDEV, sizeof(tmp_uint),
 424                                 &tmp_uint);
 425                 } else {
 426                         /* Case 2: indev is bridge group, we need to look for
 427                          * physical device (when called from ipv4) */
 428                         NFA_PUT(skb, NFQA_IFINDEX_INDEV, sizeof(tmp_uint),
 429                                 &tmp_uint);
 430                         if (entry->skb->nf_bridge
 431                             && entry->skb->nf_bridge->physindev) {
 432                                 tmp_uint = htonl(entry->skb->nf_bridge->physindev->ifindex);
 433                                 NFA_PUT(skb, NFQA_IFINDEX_PHYSINDEV,
 434                                         sizeof(tmp_uint), &tmp_uint);
 435                         }
 436                 }
 437 #endif
 438         }
 439
 440         if (entry->info->outdev) {
 441                 tmp_uint = htonl(entry->info->outdev->ifindex);
 442 #ifndef CONFIG_BRIDGE_NETFILTER
 443                 NFA_PUT(skb, NFQA_IFINDEX_OUTDEV, sizeof(tmp_uint), &tmp_uint);
 444 #else
 445                 if (entry->info->pf == PF_BRIDGE) {
 446                         /* Case 1: outdev is physical output device, we need to
 447                          * look for bridge group (when called from
 448                          * netfilter_bridge) */
 449                         NFA_PUT(skb, NFQA_IFINDEX_PHYSOUTDEV, sizeof(tmp_uint),
 450                                 &tmp_uint);
 451                         /* this is the bridge group "brX" */
 452                         tmp_uint = htonl(entry->info->outdev->br_port->br->dev->ifindex);
 453                         NFA_PUT(skb, NFQA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 454                                 &tmp_uint);
 455                 } else {
 456                         /* Case 2: outdev is bridge group, we need to look for
 457                          * physical output device (when called from ipv4) */
 458                         NFA_PUT(skb, NFQA_IFINDEX_OUTDEV, sizeof(tmp_uint),
 459                                 &tmp_uint);
 460                         if (entry->skb->nf_bridge
 461                             && entry->skb->nf_bridge->physoutdev) {
 462                                 tmp_uint = htonl(entry->skb->nf_bridge->physoutdev->ifindex);
 463                                 NFA_PUT(skb, NFQA_IFINDEX_PHYSOUTDEV,
 464                                         sizeof(tmp_uint), &tmp_uint);
 465                         }
 466                 }
 467 #endif
 468         }
 469
 470         if (entry->skb->nfmark) {
 471                 tmp_uint = htonl(entry->skb->nfmark);
 472                 NFA_PUT(skb, NFQA_MARK, sizeof(u_int32_t), &tmp_uint);
 473         }
 474
 475         if (entry->info->indev && entry->skb->dev
 476             && entry->skb->dev->hard_header_parse) {
 477                 struct nfqnl_msg_packet_hw phw;
 478
 479                 phw.hw_addrlen =
 480                         entry->skb->dev->hard_header_parse(entry->skb,
 481                                                            phw.hw_addr);
 482                 phw.hw_addrlen = htons(phw.hw_addrlen);
 483                 NFA_PUT(skb, NFQA_HWADDR, sizeof(phw), &phw);
 484         }
 485
 486         if (entry->skb->tstamp.off_sec) {
 487                 struct nfqnl_msg_packet_timestamp ts;
 488
 489                 ts.sec = cpu_to_be64(skb_tv_base.tv_sec + entry->skb->tstamp.off_sec);
 490                 ts.usec = cpu_to_be64(skb_tv_base.tv_usec + entry->skb->tstamp.off_usec);
 491
 492                 NFA_PUT(skb, NFQA_TIMESTAMP, sizeof(ts), &ts);
 493         }
 494
 495         if (data_len) {
 496                 struct nfattr *nfa;
 497                 int size = NFA_LENGTH(data_len);
 498
 499                 if (skb_tailroom(skb) < (int)NFA_SPACE(data_len)) {
 500                         printk(KERN_WARNING "nf_queue: no tailroom!\n");
 501                         goto nlmsg_failure;
 502                 }
 503
 504                 nfa = (struct nfattr *)skb_put(skb, NFA_ALIGN(size));
 505                 nfa->nfa_type = NFQA_PAYLOAD;
 506                 nfa->nfa_len = size;
 507
 508                 if (skb_copy_bits(entry->skb, 0, NFA_DATA(nfa), data_len))
 509                         BUG();
 510         }
 511
 512         nlh->nlmsg_len = skb->tail - old_tail;
 513         return skb;
 514
 515 nlmsg_failure:
 516 nfattr_failure:
 517         if (skb)
 518                 kfree_skb(skb);
 519         *errp = -EINVAL;
 520         if (net_ratelimit())
 521                 printk(KERN_ERR "nf_queue: error creating packet message\n");
 522         return NULL;
 523 }
 524
 525 static int
 526 nfqnl_enqueue_packet(struct sk_buff *skb, struct nf_info *info,
 527                      unsigned int queuenum, void *data)
 528 {
 529         int status = -EINVAL;
 530         struct sk_buff *nskb;
 531         struct nfqnl_instance *queue;
 532         struct nfqnl_queue_entry *entry;
 533
 534         QDEBUG("entered\n");
 535
 536         queue = instance_lookup_get(queuenum);
 537         if (!queue) {
 538                 QDEBUG("no queue instance matching\n");
 539                 return -EINVAL;
 540         }
 541
 542         if (queue->copy_mode == NFQNL_COPY_NONE) {
 543                 QDEBUG("mode COPY_NONE, aborting\n");
 544                 status = -EAGAIN;
 545                 goto err_out_put;
 546         }
 547
 548         entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
 549         if (entry == NULL) {
 550                 if (net_ratelimit())
 551                         printk(KERN_ERR
 552                                 "nf_queue: OOM in nfqnl_enqueue_packet()\n");
 553                 status = -ENOMEM;
 554                 goto err_out_put;
 555         }
 556
 557         entry->info = info;
 558         entry->skb = skb;
 559         entry->id = atomic_inc_return(&queue->id_sequence);
 560
 561         nskb = nfqnl_build_packet_message(queue, entry, &status);
 562         if (nskb == NULL)
 563                 goto err_out_free;
 564
 565         spin_lock_bh(&queue->lock);
 566
 567         if (!queue->peer_pid)
 568                 goto err_out_free_nskb;
 569
 570         if (queue->queue_total >= queue->queue_maxlen) {
 571                 queue->queue_dropped++;
 572                 status = -ENOSPC;
 573                 if (net_ratelimit())
 574                           printk(KERN_WARNING "ip_queue: full at %d entries, "
 575                                  "dropping packets(s). Dropped: %d\n",
 576                                  queue->queue_total, queue->queue_dropped);
 577                 goto err_out_free_nskb;
 578         }
 579
 580         /* nfnetlink_unicast will either free the nskb or add it to a socket */
 581         status = nfnetlink_unicast(nskb, queue->peer_pid, MSG_DONTWAIT);
 582         if (status < 0) {
 583                 queue->queue_user_dropped++;
 584                 goto err_out_unlock;
 585         }
 586
 587         __enqueue_entry(queue, entry);
 588
 589         spin_unlock_bh(&queue->lock);
 590         instance_put(queue);
 591         return status;
 592
 593 err_out_free_nskb:
 594         kfree_skb(nskb);
 595
 596 err_out_unlock:
 597         spin_unlock_bh(&queue->lock);
 598
 599 err_out_free:
 600         kfree(entry);
 601 err_out_put:
 602         instance_put(queue);
 603         return status;
 604 }
 605
 606 static int
 607 nfqnl_mangle(void *data, int data_len, struct nfqnl_queue_entry *e)
 608 {
 609         int diff;
 610
 611         diff = data_len - e->skb->len;
 612         if (diff < 0)
 613                 skb_trim(e->skb, data_len);
 614         else if (diff > 0) {
 615                 if (data_len > 0xFFFF)
 616                         return -EINVAL;
 617                 if (diff > skb_tailroom(e->skb)) {
 618                         struct sk_buff *newskb;
 619
 620                         newskb = skb_copy_expand(e->skb,
 621                                                  skb_headroom(e->skb),
 622                                                  diff,
 623                                                  GFP_ATOMIC);
 624                         if (newskb == NULL) {
 625                                 printk(KERN_WARNING "ip_queue: OOM "
 626                                       "in mangle, dropping packet\n");
 627                                 return -ENOMEM;
 628                         }
 629                         if (e->skb->sk)
 630                                 skb_set_owner_w(newskb, e->skb->sk);
 631                         kfree_skb(e->skb);
 632                         e->skb = newskb;
 633                 }
 634                 skb_put(e->skb, diff);
 635         }
 636         if (!skb_make_writable(&e->skb, data_len))
 637                 return -ENOMEM;
 638         memcpy(e->skb->data, data, data_len);
 639
 640         return 0;
 641 }
 642
 643 static inline int
 644 id_cmp(struct nfqnl_queue_entry *e, unsigned long id)
 645 {
 646         return (id == e->id);
 647 }
 648
 649 static int
 650 nfqnl_set_mode(struct nfqnl_instance *queue,
 651                unsigned char mode, unsigned int range)
 652 {
 653         int status;
 654
 655         spin_lock_bh(&queue->lock);
 656         status = __nfqnl_set_mode(queue, mode, range);
 657         spin_unlock_bh(&queue->lock);
 658
 659         return status;
 660 }
 661
 662 static int
 663 dev_cmp(struct nfqnl_queue_entry *entry, unsigned long ifindex)
 664 {
 665         if (entry->info->indev)
 666                 if (entry->info->indev->ifindex == ifindex)
 667                         return 1;
 668
 669         if (entry->info->outdev)
 670                 if (entry->info->outdev->ifindex == ifindex)
 671                         return 1;
 672
 673         return 0;
 674 }
 675
 676 /* drop all packets with either indev or outdev == ifindex from all queue
 677  * instances */
 678 static void
 679 nfqnl_dev_drop(int ifindex)
 680 {
 681         int i;
 682
 683         QDEBUG("entering for ifindex %u\n", ifindex);
 684
 685         /* this only looks like we have to hold the readlock for a way too long
 686          * time, issue_verdict(),  nf_reinject(), ... - but we always only
 687          * issue NF_DROP, which is processed directly in nf_reinject() */
 688         read_lock_bh(&instances_lock);
 689
 690         for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 691                 struct hlist_node *tmp;
 692                 struct nfqnl_instance *inst;
 693                 struct hlist_head *head = &instance_table[i];
 694
 695                 hlist_for_each_entry(inst, tmp, head, hlist) {
 696                         struct nfqnl_queue_entry *entry;
 697                         while ((entry = find_dequeue_entry(inst, dev_cmp,
 698                                                            ifindex)) != NULL)
 699                                 issue_verdict(entry, NF_DROP);
 700                 }
 701         }
 702
 703         read_unlock_bh(&instances_lock);
 704 }
 705
 706 #define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 707
 708 static int
 709 nfqnl_rcv_dev_event(struct notifier_block *this,
 710                     unsigned long event, void *ptr)
 711 {
 712         struct net_device *dev = ptr;
 713
 714         /* Drop any packets associated with the downed device */
 715         if (event == NETDEV_DOWN)
 716                 nfqnl_dev_drop(dev->ifindex);
 717         return NOTIFY_DONE;
 718 }
 719
 720 static struct notifier_block nfqnl_dev_notifier = {
 721         .notifier_call  = nfqnl_rcv_dev_event,
 722 };
 723
 724 static int
 725 nfqnl_rcv_nl_event(struct notifier_block *this,
 726                    unsigned long event, void *ptr)
 727 {
 728         struct netlink_notify *n = ptr;
 729
 730         if (event == NETLINK_URELEASE &&
 731             n->protocol == NETLINK_NETFILTER && n->pid) {
 732                 int i;
 733
 734                 /* destroy all instances for this pid */
 735                 write_lock_bh(&instances_lock);
 736                 for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 737                         struct hlist_node *tmp, *t2;
 738                         struct nfqnl_instance *inst;
 739                         struct hlist_head *head = &instance_table[i];
 740
 741                         hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 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 nfqnl_rtnl_notifier = {
 752         .notifier_call  = nfqnl_rcv_nl_event,
 753 };
 754
 755 static const int nfqa_verdict_min[NFQA_MAX] = {
 756         [NFQA_VERDICT_HDR-1]    = sizeof(struct nfqnl_msg_verdict_hdr),
 757         [NFQA_MARK-1]           = sizeof(u_int32_t),
 758         [NFQA_PAYLOAD-1]        = 0,
 759 };
 760
 761 static int
 762 nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb,
 763                    struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 764 {
 765         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 766         u_int16_t queue_num = ntohs(nfmsg->res_id);
 767
 768         struct nfqnl_msg_verdict_hdr *vhdr;
 769         struct nfqnl_instance *queue;
 770         unsigned int verdict;
 771         struct nfqnl_queue_entry *entry;
 772         int err;
 773
 774         if (nfattr_bad_size(nfqa, NFQA_MAX, nfqa_verdict_min)) {
 775                 QDEBUG("bad attribute size\n");
 776                 return -EINVAL;
 777         }
 778
 779         queue = instance_lookup_get(queue_num);
 780         if (!queue)
 781                 return -ENODEV;
 782
 783         if (queue->peer_pid != NETLINK_CB(skb).pid) {
 784                 err = -EPERM;
 785                 goto err_out_put;
 786         }
 787
 788         if (!nfqa[NFQA_VERDICT_HDR-1]) {
 789                 err = -EINVAL;
 790                 goto err_out_put;
 791         }
 792
 793         vhdr = NFA_DATA(nfqa[NFQA_VERDICT_HDR-1]);
 794         verdict = ntohl(vhdr->verdict);
 795
 796         if ((verdict & NF_VERDICT_MASK) > NF_MAX_VERDICT) {
 797                 err = -EINVAL;
 798                 goto err_out_put;
 799         }
 800
 801         entry = find_dequeue_entry(queue, id_cmp, ntohl(vhdr->id));
 802         if (entry == NULL) {
 803                 err = -ENOENT;
 804                 goto err_out_put;
 805         }
 806
 807         if (nfqa[NFQA_PAYLOAD-1]) {
 808                 if (nfqnl_mangle(NFA_DATA(nfqa[NFQA_PAYLOAD-1]),
 809                                  NFA_PAYLOAD(nfqa[NFQA_PAYLOAD-1]), entry) < 0)
 810                         verdict = NF_DROP;
 811         }
 812
 813         if (nfqa[NFQA_MARK-1])
 814                 skb->nfmark = ntohl(*(u_int32_t *)NFA_DATA(nfqa[NFQA_MARK-1]));
 815
 816         issue_verdict(entry, verdict);
 817         instance_put(queue);
 818         return 0;
 819
 820 err_out_put:
 821         instance_put(queue);
 822         return err;
 823 }
 824
 825 static int
 826 nfqnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 827                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 828 {
 829         return -ENOTSUPP;
 830 }
 831
 832 static const int nfqa_cfg_min[NFQA_CFG_MAX] = {
 833         [NFQA_CFG_CMD-1]        = sizeof(struct nfqnl_msg_config_cmd),
 834         [NFQA_CFG_PARAMS-1]     = sizeof(struct nfqnl_msg_config_params),
 835 };
 836
 837 static struct nf_queue_handler nfqh = {
 838         .name   = "nf_queue",
 839         .outfn  = &nfqnl_enqueue_packet,
 840 };
 841
 842 static int
 843 nfqnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 844                   struct nlmsghdr *nlh, struct nfattr *nfqa[], int *errp)
 845 {
 846         struct nfgenmsg *nfmsg = NLMSG_DATA(nlh);
 847         u_int16_t queue_num = ntohs(nfmsg->res_id);
 848         struct nfqnl_instance *queue;
 849         int ret = 0;
 850
 851         QDEBUG("entering for msg %u\n", NFNL_MSG_TYPE(nlh->nlmsg_type));
 852
 853         if (nfattr_bad_size(nfqa, NFQA_CFG_MAX, nfqa_cfg_min)) {
 854                 QDEBUG("bad attribute size\n");
 855                 return -EINVAL;
 856         }
 857
 858         queue = instance_lookup_get(queue_num);
 859         if (nfqa[NFQA_CFG_CMD-1]) {
 860                 struct nfqnl_msg_config_cmd *cmd;
 861                 cmd = NFA_DATA(nfqa[NFQA_CFG_CMD-1]);
 862                 QDEBUG("found CFG_CMD\n");
 863
 864                 switch (cmd->command) {
 865                 case NFQNL_CFG_CMD_BIND:
 866                         if (queue)
 867                                 return -EBUSY;
 868
 869                         queue = instance_create(queue_num, NETLINK_CB(skb).pid);
 870                         if (!queue)
 871                                 return -EINVAL;
 872                         break;
 873                 case NFQNL_CFG_CMD_UNBIND:
 874                         if (!queue)
 875                                 return -ENODEV;
 876
 877                         if (queue->peer_pid != NETLINK_CB(skb).pid) {
 878                                 ret = -EPERM;
 879                                 goto out_put;
 880                         }
 881
 882                         instance_destroy(queue);
 883                         break;
 884                 case NFQNL_CFG_CMD_PF_BIND:
 885                         QDEBUG("registering queue handler for pf=%u\n",
 886                                 ntohs(cmd->pf));
 887                         ret = nf_register_queue_handler(ntohs(cmd->pf), &nfqh);
 888                         break;
 889                 case NFQNL_CFG_CMD_PF_UNBIND:
 890                         QDEBUG("unregistering queue handler for pf=%u\n",
 891                                 ntohs(cmd->pf));
 892                         /* This is a bug and a feature.  We can unregister
 893                          * other handlers(!) */
 894                         ret = nf_unregister_queue_handler(ntohs(cmd->pf));
 895                         break;
 896                 default:
 897                         ret = -EINVAL;
 898                         break;
 899                 }
 900         } else {
 901                 if (!queue) {
 902                         QDEBUG("no config command, and no instance ENOENT\n");
 903                         ret = -ENOENT;
 904                         goto out_put;
 905                 }
 906
 907                 if (queue->peer_pid != NETLINK_CB(skb).pid) {
 908                         QDEBUG("no config command, and wrong pid\n");
 909                         ret = -EPERM;
 910                         goto out_put;
 911                 }
 912         }
 913
 914         if (nfqa[NFQA_CFG_PARAMS-1]) {
 915                 struct nfqnl_msg_config_params *params;
 916                 params = NFA_DATA(nfqa[NFQA_CFG_PARAMS-1]);
 917
 918                 nfqnl_set_mode(queue, params->copy_mode,
 919                                 ntohl(params->copy_range));
 920         }
 921
 922 out_put:
 923         instance_put(queue);
 924         return ret;
 925 }
 926
 927 static struct nfnl_callback nfqnl_cb[NFQNL_MSG_MAX] = {
 928         [NFQNL_MSG_PACKET]      = { .call = nfqnl_recv_unsupp,
 929                                     .attr_count = NFQA_MAX,
 930                                     .cap_required = CAP_NET_ADMIN },
 931         [NFQNL_MSG_VERDICT]     = { .call = nfqnl_recv_verdict,
 932                                     .attr_count = NFQA_MAX,
 933                                     .cap_required = CAP_NET_ADMIN },
 934         [NFQNL_MSG_CONFIG]      = { .call = nfqnl_recv_config,
 935                                     .attr_count = NFQA_CFG_MAX,
 936                                     .cap_required = CAP_NET_ADMIN },
 937 };
 938
 939 static struct nfnetlink_subsystem nfqnl_subsys = {
 940         .name           = "nf_queue",
 941         .subsys_id      = NFNL_SUBSYS_QUEUE,
 942         .cb_count       = NFQNL_MSG_MAX,
 943         .cb             = nfqnl_cb,
 944 };
 945
 946 #ifdef CONFIG_PROC_FS
 947 struct iter_state {
 948         unsigned int bucket;
 949 };
 950
 951 static struct hlist_node *get_first(struct seq_file *seq)
 952 {
 953         struct iter_state *st = seq->private;
 954
 955         if (!st)
 956                 return NULL;
 957
 958         for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 959                 if (!hlist_empty(&instance_table[st->bucket]))
 960                         return instance_table[st->bucket].first;
 961         }
 962         return NULL;
 963 }
 964
 965 static struct hlist_node *get_next(struct seq_file *seq, struct hlist_node *h)
 966 {
 967         struct iter_state *st = seq->private;
 968
 969         h = h->next;
 970         while (!h) {
 971                 if (++st->bucket >= INSTANCE_BUCKETS)
 972                         return NULL;
 973
 974                 h = instance_table[st->bucket].first;
 975         }
 976         return h;
 977 }
 978
 979 static struct hlist_node *get_idx(struct seq_file *seq, loff_t pos)
 980 {
 981         struct hlist_node *head;
 982         head = get_first(seq);
 983
 984         if (head)
 985                 while (pos && (head = get_next(seq, head)))
 986                         pos--;
 987         return pos ? NULL : head;
 988 }
 989
 990 static void *seq_start(struct seq_file *seq, loff_t *pos)
 991 {
 992         read_lock_bh(&instances_lock);
 993         return get_idx(seq, *pos);
 994 }
 995
 996 static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 997 {
 998         (*pos)++;
 999         return get_next(s, v);
1000 }
1001
1002 static void seq_stop(struct seq_file *s, void *v)
1003 {
1004         read_unlock_bh(&instances_lock);
1005 }
1006
1007 static int seq_show(struct seq_file *s, void *v)
1008 {
1009         const struct nfqnl_instance *inst = v;
1010
1011         return seq_printf(s, "%5d %6d %5d %1d %5d %5d %5d %8d %2d\n",
1012                           inst->queue_num,
1013                           inst->peer_pid, inst->queue_total,
1014                           inst->copy_mode, inst->copy_range,
1015                           inst->queue_dropped, inst->queue_user_dropped,
1016                           atomic_read(&inst->id_sequence),
1017                           atomic_read(&inst->use));
1018 }
1019
1020 static struct seq_operations nfqnl_seq_ops = {
1021         .start  = seq_start,
1022         .next   = seq_next,
1023         .stop   = seq_stop,
1024         .show   = seq_show,
1025 };
1026
1027 static int nfqnl_open(struct inode *inode, struct file *file)
1028 {
1029         struct seq_file *seq;
1030         struct iter_state *is;
1031         int ret;
1032
1033         is = kmalloc(sizeof(*is), GFP_KERNEL);
1034         if (!is)
1035                 return -ENOMEM;
1036         memset(is, 0, sizeof(*is));
1037         ret = seq_open(file, &nfqnl_seq_ops);
1038         if (ret < 0)
1039                 goto out_free;
1040         seq = file->private_data;
1041         seq->private = is;
1042         return ret;
1043 out_free:
1044         kfree(is);
1045         return ret;
1046 }
1047
1048 static struct file_operations nfqnl_file_ops = {
1049         .owner   = THIS_MODULE,
1050         .open    = nfqnl_open,
1051         .read    = seq_read,
1052         .llseek  = seq_lseek,
1053         .release = seq_release_private,
1054 };
1055
1056 #endif /* PROC_FS */
1057
1058 static int
1059 init_or_cleanup(int init)
1060 {
1061         int i, status = -ENOMEM;
1062 #ifdef CONFIG_PROC_FS
1063         struct proc_dir_entry *proc_nfqueue;
1064 #endif
1065
1066         if (!init)
1067                 goto cleanup;
1068
1069         for (i = 0; i < INSTANCE_BUCKETS; i++)
1070                 INIT_HLIST_HEAD(&instance_table[i]);
1071
1072         netlink_register_notifier(&nfqnl_rtnl_notifier);
1073         status = nfnetlink_subsys_register(&nfqnl_subsys);
1074         if (status < 0) {
1075                 printk(KERN_ERR "nf_queue: failed to create netlink socket\n");
1076                 goto cleanup_netlink_notifier;
1077         }
1078
1079 #ifdef CONFIG_PROC_FS
1080         proc_nfqueue = create_proc_entry("nfnetlink_queue", 0440,
1081                                          proc_net_netfilter);
1082         if (!proc_nfqueue)
1083                 goto cleanup_subsys;
1084         proc_nfqueue->proc_fops = &nfqnl_file_ops;
1085 #endif
1086
1087         register_netdevice_notifier(&nfqnl_dev_notifier);
1088
1089         return status;
1090
1091 cleanup:
1092         nf_unregister_queue_handlers(&nfqh);
1093         unregister_netdevice_notifier(&nfqnl_dev_notifier);
1094 #ifdef CONFIG_PROC_FS
1095         remove_proc_entry("nfnetlink_queue", proc_net_netfilter);
1096 cleanup_subsys:
1097 #endif
1098         nfnetlink_subsys_unregister(&nfqnl_subsys);
1099 cleanup_netlink_notifier:
1100         netlink_unregister_notifier(&nfqnl_rtnl_notifier);
1101         return status;
1102 }
1103
1104 static int __init init(void)
1105 {
1106
1107         return init_or_cleanup(1);
1108 }
1109
1110 static void __exit fini(void)
1111 {
1112         init_or_cleanup(0);
1113 }
1114
1115 MODULE_DESCRIPTION("netfilter packet queue handler");
1116 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1117 MODULE_LICENSE("GPL");
1118 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_QUEUE);
1119
1120 module_init(init);
1121 module_exit(fini);