linux/net/netfilter/nfnetlink_log.c
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   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 <linux/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
  50struct 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        struct user_namespace *peer_user_ns;    /* User namespace of the peer process */
  59        int peer_portid;                        /* PORTID of the peer process */
  60
  61        /* configurable parameters */
  62        unsigned int flushtimeout;      /* timeout until queue flush */
  63        unsigned int nlbufsiz;          /* netlink buffer allocation size */
  64        unsigned int qthreshold;        /* threshold of the queue */
  65        u_int32_t copy_range;
  66        u_int32_t seq;                  /* instance-local sequential counter */
  67        u_int16_t group_num;            /* number of this queue */
  68        u_int16_t flags;
  69        u_int8_t copy_mode;
  70        struct rcu_head rcu;
  71};
  72
  73static DEFINE_SPINLOCK(instances_lock);
  74static atomic_t global_seq;
  75
  76#define INSTANCE_BUCKETS        16
  77static struct hlist_head instance_table[INSTANCE_BUCKETS];
  78static unsigned int hash_init;
  79
  80static inline u_int8_t instance_hashfn(u_int16_t group_num)
  81{
  82        return ((group_num & 0xff) % INSTANCE_BUCKETS);
  83}
  84
  85static struct nfulnl_instance *
  86__instance_lookup(u_int16_t group_num)
  87{
  88        struct hlist_head *head;
  89        struct hlist_node *pos;
  90        struct nfulnl_instance *inst;
  91
  92        head = &instance_table[instance_hashfn(group_num)];
  93        hlist_for_each_entry_rcu(inst, pos, head, hlist) {
  94                if (inst->group_num == group_num)
  95                        return inst;
  96        }
  97        return NULL;
  98}
  99
 100static inline void
 101instance_get(struct nfulnl_instance *inst)
 102{
 103        atomic_inc(&inst->use);
 104}
 105
 106static struct nfulnl_instance *
 107instance_lookup_get(u_int16_t group_num)
 108{
 109        struct nfulnl_instance *inst;
 110
 111        rcu_read_lock_bh();
 112        inst = __instance_lookup(group_num);
 113        if (inst && !atomic_inc_not_zero(&inst->use))
 114                inst = NULL;
 115        rcu_read_unlock_bh();
 116
 117        return inst;
 118}
 119
 120static void nfulnl_instance_free_rcu(struct rcu_head *head)
 121{
 122        kfree(container_of(head, struct nfulnl_instance, rcu));
 123        module_put(THIS_MODULE);
 124}
 125
 126static void
 127instance_put(struct nfulnl_instance *inst)
 128{
 129        if (inst && atomic_dec_and_test(&inst->use))
 130                call_rcu_bh(&inst->rcu, nfulnl_instance_free_rcu);
 131}
 132
 133static void nfulnl_timer(unsigned long data);
 134
 135static struct nfulnl_instance *
 136instance_create(u_int16_t group_num, int portid, struct user_namespace *user_ns)
 137{
 138        struct nfulnl_instance *inst;
 139        int err;
 140
 141        spin_lock_bh(&instances_lock);
 142        if (__instance_lookup(group_num)) {
 143                err = -EEXIST;
 144                goto out_unlock;
 145        }
 146
 147        inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
 148        if (!inst) {
 149                err = -ENOMEM;
 150                goto out_unlock;
 151        }
 152
 153        if (!try_module_get(THIS_MODULE)) {
 154                kfree(inst);
 155                err = -EAGAIN;
 156                goto out_unlock;
 157        }
 158
 159        INIT_HLIST_NODE(&inst->hlist);
 160        spin_lock_init(&inst->lock);
 161        /* needs to be two, since we _put() after creation */
 162        atomic_set(&inst->use, 2);
 163
 164        setup_timer(&inst->timer, nfulnl_timer, (unsigned long)inst);
 165
 166        inst->peer_user_ns = user_ns;
 167        inst->peer_portid = portid;
 168        inst->group_num = group_num;
 169
 170        inst->qthreshold        = NFULNL_QTHRESH_DEFAULT;
 171        inst->flushtimeout      = NFULNL_TIMEOUT_DEFAULT;
 172        inst->nlbufsiz          = NFULNL_NLBUFSIZ_DEFAULT;
 173        inst->copy_mode         = NFULNL_COPY_PACKET;
 174        inst->copy_range        = NFULNL_COPY_RANGE_MAX;
 175
 176        hlist_add_head_rcu(&inst->hlist,
 177                       &instance_table[instance_hashfn(group_num)]);
 178
 179        spin_unlock_bh(&instances_lock);
 180
 181        return inst;
 182
 183out_unlock:
 184        spin_unlock_bh(&instances_lock);
 185        return ERR_PTR(err);
 186}
 187
 188static void __nfulnl_flush(struct nfulnl_instance *inst);
 189
 190/* called with BH disabled */
 191static void
 192__instance_destroy(struct nfulnl_instance *inst)
 193{
 194        /* first pull it out of the global list */
 195        hlist_del_rcu(&inst->hlist);
 196
 197        /* then flush all pending packets from skb */
 198
 199        spin_lock(&inst->lock);
 200
 201        /* lockless readers wont be able to use us */
 202        inst->copy_mode = NFULNL_COPY_DISABLED;
 203
 204        if (inst->skb)
 205                __nfulnl_flush(inst);
 206        spin_unlock(&inst->lock);
 207
 208        /* and finally put the refcount */
 209        instance_put(inst);
 210}
 211
 212static inline void
 213instance_destroy(struct nfulnl_instance *inst)
 214{
 215        spin_lock_bh(&instances_lock);
 216        __instance_destroy(inst);
 217        spin_unlock_bh(&instances_lock);
 218}
 219
 220static int
 221nfulnl_set_mode(struct nfulnl_instance *inst, u_int8_t mode,
 222                  unsigned int range)
 223{
 224        int status = 0;
 225
 226        spin_lock_bh(&inst->lock);
 227
 228        switch (mode) {
 229        case NFULNL_COPY_NONE:
 230        case NFULNL_COPY_META:
 231                inst->copy_mode = mode;
 232                inst->copy_range = 0;
 233                break;
 234
 235        case NFULNL_COPY_PACKET:
 236                inst->copy_mode = mode;
 237                inst->copy_range = min_t(unsigned int,
 238                                         range, NFULNL_COPY_RANGE_MAX);
 239                break;
 240
 241        default:
 242                status = -EINVAL;
 243                break;
 244        }
 245
 246        spin_unlock_bh(&inst->lock);
 247
 248        return status;
 249}
 250
 251static int
 252nfulnl_set_nlbufsiz(struct nfulnl_instance *inst, u_int32_t nlbufsiz)
 253{
 254        int status;
 255
 256        spin_lock_bh(&inst->lock);
 257        if (nlbufsiz < NFULNL_NLBUFSIZ_DEFAULT)
 258                status = -ERANGE;
 259        else if (nlbufsiz > 131072)
 260                status = -ERANGE;
 261        else {
 262                inst->nlbufsiz = nlbufsiz;
 263                status = 0;
 264        }
 265        spin_unlock_bh(&inst->lock);
 266
 267        return status;
 268}
 269
 270static int
 271nfulnl_set_timeout(struct nfulnl_instance *inst, u_int32_t timeout)
 272{
 273        spin_lock_bh(&inst->lock);
 274        inst->flushtimeout = timeout;
 275        spin_unlock_bh(&inst->lock);
 276
 277        return 0;
 278}
 279
 280static int
 281nfulnl_set_qthresh(struct nfulnl_instance *inst, u_int32_t qthresh)
 282{
 283        spin_lock_bh(&inst->lock);
 284        inst->qthreshold = qthresh;
 285        spin_unlock_bh(&inst->lock);
 286
 287        return 0;
 288}
 289
 290static int
 291nfulnl_set_flags(struct nfulnl_instance *inst, u_int16_t flags)
 292{
 293        spin_lock_bh(&inst->lock);
 294        inst->flags = flags;
 295        spin_unlock_bh(&inst->lock);
 296
 297        return 0;
 298}
 299
 300static struct sk_buff *
 301nfulnl_alloc_skb(unsigned int inst_size, unsigned int pkt_size)
 302{
 303        struct sk_buff *skb;
 304        unsigned int n;
 305
 306        /* alloc skb which should be big enough for a whole multipart
 307         * message.  WARNING: has to be <= 128k due to slab restrictions */
 308
 309        n = max(inst_size, pkt_size);
 310        skb = alloc_skb(n, GFP_ATOMIC);
 311        if (!skb) {
 312                if (n > pkt_size) {
 313                        /* try to allocate only as much as we need for current
 314                         * packet */
 315
 316                        skb = alloc_skb(pkt_size, GFP_ATOMIC);
 317                        if (!skb)
 318                                pr_err("nfnetlink_log: can't even alloc %u bytes\n",
 319                                       pkt_size);
 320                }
 321        }
 322
 323        return skb;
 324}
 325
 326static int
 327__nfulnl_send(struct nfulnl_instance *inst)
 328{
 329        int status = -1;
 330
 331        if (inst->qlen > 1) {
 332                struct nlmsghdr *nlh = nlmsg_put(inst->skb, 0, 0,
 333                                                 NLMSG_DONE,
 334                                                 sizeof(struct nfgenmsg),
 335                                                 0);
 336                if (!nlh)
 337                        goto out;
 338        }
 339        status = nfnetlink_unicast(inst->skb, &init_net, inst->peer_portid,
 340                                   MSG_DONTWAIT);
 341
 342        inst->qlen = 0;
 343        inst->skb = NULL;
 344out:
 345        return status;
 346}
 347
 348static void
 349__nfulnl_flush(struct nfulnl_instance *inst)
 350{
 351        /* timer holds a reference */
 352        if (del_timer(&inst->timer))
 353                instance_put(inst);
 354        if (inst->skb)
 355                __nfulnl_send(inst);
 356}
 357
 358static void
 359nfulnl_timer(unsigned long data)
 360{
 361        struct nfulnl_instance *inst = (struct nfulnl_instance *)data;
 362
 363        spin_lock_bh(&inst->lock);
 364        if (inst->skb)
 365                __nfulnl_send(inst);
 366        spin_unlock_bh(&inst->lock);
 367        instance_put(inst);
 368}
 369
 370/* This is an inline function, we don't really care about a long
 371 * list of arguments */
 372static inline int
 373__build_packet_message(struct nfulnl_instance *inst,
 374                        const struct sk_buff *skb,
 375                        unsigned int data_len,
 376                        u_int8_t pf,
 377                        unsigned int hooknum,
 378                        const struct net_device *indev,
 379                        const struct net_device *outdev,
 380                        const char *prefix, unsigned int plen)
 381{
 382        struct nfulnl_msg_packet_hdr pmsg;
 383        struct nlmsghdr *nlh;
 384        struct nfgenmsg *nfmsg;
 385        sk_buff_data_t old_tail = inst->skb->tail;
 386        struct sock *sk;
 387
 388        nlh = nlmsg_put(inst->skb, 0, 0,
 389                        NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET,
 390                        sizeof(struct nfgenmsg), 0);
 391        if (!nlh)
 392                return -1;
 393        nfmsg = nlmsg_data(nlh);
 394        nfmsg->nfgen_family = pf;
 395        nfmsg->version = NFNETLINK_V0;
 396        nfmsg->res_id = htons(inst->group_num);
 397
 398        pmsg.hw_protocol        = skb->protocol;
 399        pmsg.hook               = hooknum;
 400
 401        if (nla_put(inst->skb, NFULA_PACKET_HDR, sizeof(pmsg), &pmsg))
 402                goto nla_put_failure;
 403
 404        if (prefix &&
 405            nla_put(inst->skb, NFULA_PREFIX, plen, prefix))
 406                goto nla_put_failure;
 407
 408        if (indev) {
 409#ifndef CONFIG_BRIDGE_NETFILTER
 410                if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 411                                 htonl(indev->ifindex)))
 412                        goto nla_put_failure;
 413#else
 414                if (pf == PF_BRIDGE) {
 415                        /* Case 1: outdev is physical input device, we need to
 416                         * look for bridge group (when called from
 417                         * netfilter_bridge) */
 418                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 419                                         htonl(indev->ifindex)) ||
 420                        /* this is the bridge group "brX" */
 421                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 422                            nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 423                                         htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 424                                goto nla_put_failure;
 425                } else {
 426                        /* Case 2: indev is bridge group, we need to look for
 427                         * physical device (when called from ipv4) */
 428                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 429                                         htonl(indev->ifindex)))
 430                                goto nla_put_failure;
 431                        if (skb->nf_bridge && skb->nf_bridge->physindev &&
 432                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 433                                         htonl(skb->nf_bridge->physindev->ifindex)))
 434                                goto nla_put_failure;
 435                }
 436#endif
 437        }
 438
 439        if (outdev) {
 440#ifndef CONFIG_BRIDGE_NETFILTER
 441                if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 442                                 htonl(outdev->ifindex)))
 443                        goto nla_put_failure;
 444#else
 445                if (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                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 450                                         htonl(outdev->ifindex)) ||
 451                        /* this is the bridge group "brX" */
 452                        /* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
 453                            nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 454                                         htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 455                                goto nla_put_failure;
 456                } else {
 457                        /* Case 2: indev is a bridge group, we need to look
 458                         * for physical device (when called from ipv4) */
 459                        if (nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 460                                         htonl(outdev->ifindex)))
 461                                goto nla_put_failure;
 462                        if (skb->nf_bridge && skb->nf_bridge->physoutdev &&
 463                            nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 464                                         htonl(skb->nf_bridge->physoutdev->ifindex)))
 465                                goto nla_put_failure;
 466                }
 467#endif
 468        }
 469
 470        if (skb->mark &&
 471            nla_put_be32(inst->skb, NFULA_MARK, htonl(skb->mark)))
 472                goto nla_put_failure;
 473
 474        if (indev && skb->dev &&
 475            skb->mac_header != skb->network_header) {
 476                struct nfulnl_msg_packet_hw phw;
 477                int len = dev_parse_header(skb, phw.hw_addr);
 478                if (len > 0) {
 479                        phw.hw_addrlen = htons(len);
 480                        if (nla_put(inst->skb, NFULA_HWADDR, sizeof(phw), &phw))
 481                                goto nla_put_failure;
 482                }
 483        }
 484
 485        if (indev && skb_mac_header_was_set(skb)) {
 486                if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 487                    nla_put_be16(inst->skb, NFULA_HWLEN,
 488                                 htons(skb->dev->hard_header_len)) ||
 489                    nla_put(inst->skb, NFULA_HWHEADER, skb->dev->hard_header_len,
 490                            skb_mac_header(skb)))
 491                        goto nla_put_failure;
 492        }
 493
 494        if (skb->tstamp.tv64) {
 495                struct nfulnl_msg_packet_timestamp ts;
 496                struct timeval tv = ktime_to_timeval(skb->tstamp);
 497                ts.sec = cpu_to_be64(tv.tv_sec);
 498                ts.usec = cpu_to_be64(tv.tv_usec);
 499
 500                if (nla_put(inst->skb, NFULA_TIMESTAMP, sizeof(ts), &ts))
 501                        goto nla_put_failure;
 502        }
 503
 504        /* UID */
 505        sk = skb->sk;
 506        if (sk && sk->sk_state != TCP_TIME_WAIT) {
 507                read_lock_bh(&sk->sk_callback_lock);
 508                if (sk->sk_socket && sk->sk_socket->file) {
 509                        struct file *file = sk->sk_socket->file;
 510                        const struct cred *cred = file->f_cred;
 511                        struct user_namespace *user_ns = inst->peer_user_ns;
 512                        __be32 uid = htonl(from_kuid_munged(user_ns, cred->fsuid));
 513                        __be32 gid = htonl(from_kgid_munged(user_ns, cred->fsgid));
 514                        read_unlock_bh(&sk->sk_callback_lock);
 515                        if (nla_put_be32(inst->skb, NFULA_UID, uid) ||
 516                            nla_put_be32(inst->skb, NFULA_GID, gid))
 517                                goto nla_put_failure;
 518                } else
 519                        read_unlock_bh(&sk->sk_callback_lock);
 520        }
 521
 522        /* local sequence number */
 523        if ((inst->flags & NFULNL_CFG_F_SEQ) &&
 524            nla_put_be32(inst->skb, NFULA_SEQ, htonl(inst->seq++)))
 525                goto nla_put_failure;
 526
 527        /* global sequence number */
 528        if ((inst->flags & NFULNL_CFG_F_SEQ_GLOBAL) &&
 529            nla_put_be32(inst->skb, NFULA_SEQ_GLOBAL,
 530                         htonl(atomic_inc_return(&global_seq))))
 531                goto nla_put_failure;
 532
 533        if (data_len) {
 534                struct nlattr *nla;
 535                int size = nla_attr_size(data_len);
 536
 537                if (skb_tailroom(inst->skb) < nla_total_size(data_len)) {
 538                        printk(KERN_WARNING "nfnetlink_log: no tailroom!\n");
 539                        return -1;
 540                }
 541
 542                nla = (struct nlattr *)skb_put(inst->skb, nla_total_size(data_len));
 543                nla->nla_type = NFULA_PAYLOAD;
 544                nla->nla_len = size;
 545
 546                if (skb_copy_bits(skb, 0, nla_data(nla), data_len))
 547                        BUG();
 548        }
 549
 550        nlh->nlmsg_len = inst->skb->tail - old_tail;
 551        return 0;
 552
 553nla_put_failure:
 554        PRINTR(KERN_ERR "nfnetlink_log: error creating log nlmsg\n");
 555        return -1;
 556}
 557
 558#define RCV_SKB_FAIL(err) do { netlink_ack(skb, nlh, (err)); return; } while (0)
 559
 560static struct nf_loginfo default_loginfo = {
 561        .type =         NF_LOG_TYPE_ULOG,
 562        .u = {
 563                .ulog = {
 564                        .copy_len       = 0xffff,
 565                        .group          = 0,
 566                        .qthreshold     = 1,
 567                },
 568        },
 569};
 570
 571/* log handler for internal netfilter logging api */
 572void
 573nfulnl_log_packet(u_int8_t pf,
 574                  unsigned int hooknum,
 575                  const struct sk_buff *skb,
 576                  const struct net_device *in,
 577                  const struct net_device *out,
 578                  const struct nf_loginfo *li_user,
 579                  const char *prefix)
 580{
 581        unsigned int size, data_len;
 582        struct nfulnl_instance *inst;
 583        const struct nf_loginfo *li;
 584        unsigned int qthreshold;
 585        unsigned int plen;
 586
 587        if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
 588                li = li_user;
 589        else
 590                li = &default_loginfo;
 591
 592        inst = instance_lookup_get(li->u.ulog.group);
 593        if (!inst)
 594                return;
 595
 596        plen = 0;
 597        if (prefix)
 598                plen = strlen(prefix) + 1;
 599
 600        /* FIXME: do we want to make the size calculation conditional based on
 601         * what is actually present?  way more branches and checks, but more
 602         * memory efficient... */
 603        size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 604                + nla_total_size(sizeof(struct nfulnl_msg_packet_hdr))
 605                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 606                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 607#ifdef CONFIG_BRIDGE_NETFILTER
 608                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 609                + nla_total_size(sizeof(u_int32_t))     /* ifindex */
 610#endif
 611                + nla_total_size(sizeof(u_int32_t))     /* mark */
 612                + nla_total_size(sizeof(u_int32_t))     /* uid */
 613                + nla_total_size(sizeof(u_int32_t))     /* gid */
 614                + nla_total_size(plen)                  /* prefix */
 615                + nla_total_size(sizeof(struct nfulnl_msg_packet_hw))
 616                + nla_total_size(sizeof(struct nfulnl_msg_packet_timestamp));
 617
 618        if (in && skb_mac_header_was_set(skb)) {
 619                size +=   nla_total_size(skb->dev->hard_header_len)
 620                        + nla_total_size(sizeof(u_int16_t))     /* hwtype */
 621                        + nla_total_size(sizeof(u_int16_t));    /* hwlen */
 622        }
 623
 624        spin_lock_bh(&inst->lock);
 625
 626        if (inst->flags & NFULNL_CFG_F_SEQ)
 627                size += nla_total_size(sizeof(u_int32_t));
 628        if (inst->flags & NFULNL_CFG_F_SEQ_GLOBAL)
 629                size += nla_total_size(sizeof(u_int32_t));
 630
 631        qthreshold = inst->qthreshold;
 632        /* per-rule qthreshold overrides per-instance */
 633        if (li->u.ulog.qthreshold)
 634                if (qthreshold > li->u.ulog.qthreshold)
 635                        qthreshold = li->u.ulog.qthreshold;
 636
 637
 638        switch (inst->copy_mode) {
 639        case NFULNL_COPY_META:
 640        case NFULNL_COPY_NONE:
 641                data_len = 0;
 642                break;
 643
 644        case NFULNL_COPY_PACKET:
 645                if (inst->copy_range == 0
 646                    || inst->copy_range > skb->len)
 647                        data_len = skb->len;
 648                else
 649                        data_len = inst->copy_range;
 650
 651                size += nla_total_size(data_len);
 652                break;
 653
 654        case NFULNL_COPY_DISABLED:
 655        default:
 656                goto unlock_and_release;
 657        }
 658
 659        if (inst->skb &&
 660            size > skb_tailroom(inst->skb) - sizeof(struct nfgenmsg)) {
 661                /* either the queue len is too high or we don't have
 662                 * enough room in the skb left. flush to userspace. */
 663                __nfulnl_flush(inst);
 664        }
 665
 666        if (!inst->skb) {
 667                inst->skb = nfulnl_alloc_skb(inst->nlbufsiz, size);
 668                if (!inst->skb)
 669                        goto alloc_failure;
 670        }
 671
 672        inst->qlen++;
 673
 674        __build_packet_message(inst, skb, data_len, pf,
 675                                hooknum, in, out, prefix, plen);
 676
 677        if (inst->qlen >= qthreshold)
 678                __nfulnl_flush(inst);
 679        /* timer_pending always called within inst->lock, so there
 680         * is no chance of a race here */
 681        else if (!timer_pending(&inst->timer)) {
 682                instance_get(inst);
 683                inst->timer.expires = jiffies + (inst->flushtimeout*HZ/100);
 684                add_timer(&inst->timer);
 685        }
 686
 687unlock_and_release:
 688        spin_unlock_bh(&inst->lock);
 689        instance_put(inst);
 690        return;
 691
 692alloc_failure:
 693        /* FIXME: statistics */
 694        goto unlock_and_release;
 695}
 696EXPORT_SYMBOL_GPL(nfulnl_log_packet);
 697
 698static int
 699nfulnl_rcv_nl_event(struct notifier_block *this,
 700                   unsigned long event, void *ptr)
 701{
 702        struct netlink_notify *n = ptr;
 703
 704        if (event == NETLINK_URELEASE && n->protocol == NETLINK_NETFILTER) {
 705                int i;
 706
 707                /* destroy all instances for this portid */
 708                spin_lock_bh(&instances_lock);
 709                for  (i = 0; i < INSTANCE_BUCKETS; i++) {
 710                        struct hlist_node *tmp, *t2;
 711                        struct nfulnl_instance *inst;
 712                        struct hlist_head *head = &instance_table[i];
 713
 714                        hlist_for_each_entry_safe(inst, tmp, t2, head, hlist) {
 715                                if ((net_eq(n->net, &init_net)) &&
 716                                    (n->portid == inst->peer_portid))
 717                                        __instance_destroy(inst);
 718                        }
 719                }
 720                spin_unlock_bh(&instances_lock);
 721        }
 722        return NOTIFY_DONE;
 723}
 724
 725static struct notifier_block nfulnl_rtnl_notifier = {
 726        .notifier_call  = nfulnl_rcv_nl_event,
 727};
 728
 729static int
 730nfulnl_recv_unsupp(struct sock *ctnl, struct sk_buff *skb,
 731                   const struct nlmsghdr *nlh,
 732                   const struct nlattr * const nfqa[])
 733{
 734        return -ENOTSUPP;
 735}
 736
 737static struct nf_logger nfulnl_logger __read_mostly = {
 738        .name   = "nfnetlink_log",
 739        .logfn  = &nfulnl_log_packet,
 740        .me     = THIS_MODULE,
 741};
 742
 743static const struct nla_policy nfula_cfg_policy[NFULA_CFG_MAX+1] = {
 744        [NFULA_CFG_CMD]         = { .len = sizeof(struct nfulnl_msg_config_cmd) },
 745        [NFULA_CFG_MODE]        = { .len = sizeof(struct nfulnl_msg_config_mode) },
 746        [NFULA_CFG_TIMEOUT]     = { .type = NLA_U32 },
 747        [NFULA_CFG_QTHRESH]     = { .type = NLA_U32 },
 748        [NFULA_CFG_NLBUFSIZ]    = { .type = NLA_U32 },
 749        [NFULA_CFG_FLAGS]       = { .type = NLA_U16 },
 750};
 751
 752static int
 753nfulnl_recv_config(struct sock *ctnl, struct sk_buff *skb,
 754                   const struct nlmsghdr *nlh,
 755                   const struct nlattr * const nfula[])
 756{
 757        struct nfgenmsg *nfmsg = nlmsg_data(nlh);
 758        u_int16_t group_num = ntohs(nfmsg->res_id);
 759        struct nfulnl_instance *inst;
 760        struct nfulnl_msg_config_cmd *cmd = NULL;
 761        int ret = 0;
 762
 763        if (nfula[NFULA_CFG_CMD]) {
 764                u_int8_t pf = nfmsg->nfgen_family;
 765                cmd = nla_data(nfula[NFULA_CFG_CMD]);
 766
 767                /* Commands without queue context */
 768                switch (cmd->command) {
 769                case NFULNL_CFG_CMD_PF_BIND:
 770                        return nf_log_bind_pf(pf, &nfulnl_logger);
 771                case NFULNL_CFG_CMD_PF_UNBIND:
 772                        nf_log_unbind_pf(pf);
 773                        return 0;
 774                }
 775        }
 776
 777        inst = instance_lookup_get(group_num);
 778        if (inst && inst->peer_portid != NETLINK_CB(skb).portid) {
 779                ret = -EPERM;
 780                goto out_put;
 781        }
 782
 783        if (cmd != NULL) {
 784                switch (cmd->command) {
 785                case NFULNL_CFG_CMD_BIND:
 786                        if (inst) {
 787                                ret = -EBUSY;
 788                                goto out_put;
 789                        }
 790
 791                        inst = instance_create(group_num,
 792                                               NETLINK_CB(skb).portid,
 793                                               sk_user_ns(NETLINK_CB(skb).ssk));
 794                        if (IS_ERR(inst)) {
 795                                ret = PTR_ERR(inst);
 796                                goto out;
 797                        }
 798                        break;
 799                case NFULNL_CFG_CMD_UNBIND:
 800                        if (!inst) {
 801                                ret = -ENODEV;
 802                                goto out;
 803                        }
 804
 805                        instance_destroy(inst);
 806                        goto out_put;
 807                default:
 808                        ret = -ENOTSUPP;
 809                        break;
 810                }
 811        }
 812
 813        if (nfula[NFULA_CFG_MODE]) {
 814                struct nfulnl_msg_config_mode *params;
 815                params = nla_data(nfula[NFULA_CFG_MODE]);
 816
 817                if (!inst) {
 818                        ret = -ENODEV;
 819                        goto out;
 820                }
 821                nfulnl_set_mode(inst, params->copy_mode,
 822                                ntohl(params->copy_range));
 823        }
 824
 825        if (nfula[NFULA_CFG_TIMEOUT]) {
 826                __be32 timeout = nla_get_be32(nfula[NFULA_CFG_TIMEOUT]);
 827
 828                if (!inst) {
 829                        ret = -ENODEV;
 830                        goto out;
 831                }
 832                nfulnl_set_timeout(inst, ntohl(timeout));
 833        }
 834
 835        if (nfula[NFULA_CFG_NLBUFSIZ]) {
 836                __be32 nlbufsiz = nla_get_be32(nfula[NFULA_CFG_NLBUFSIZ]);
 837
 838                if (!inst) {
 839                        ret = -ENODEV;
 840                        goto out;
 841                }
 842                nfulnl_set_nlbufsiz(inst, ntohl(nlbufsiz));
 843        }
 844
 845        if (nfula[NFULA_CFG_QTHRESH]) {
 846                __be32 qthresh = nla_get_be32(nfula[NFULA_CFG_QTHRESH]);
 847
 848                if (!inst) {
 849                        ret = -ENODEV;
 850                        goto out;
 851                }
 852                nfulnl_set_qthresh(inst, ntohl(qthresh));
 853        }
 854
 855        if (nfula[NFULA_CFG_FLAGS]) {
 856                __be16 flags = nla_get_be16(nfula[NFULA_CFG_FLAGS]);
 857
 858                if (!inst) {
 859                        ret = -ENODEV;
 860                        goto out;
 861                }
 862                nfulnl_set_flags(inst, ntohs(flags));
 863        }
 864
 865out_put:
 866        instance_put(inst);
 867out:
 868        return ret;
 869}
 870
 871static const struct nfnl_callback nfulnl_cb[NFULNL_MSG_MAX] = {
 872        [NFULNL_MSG_PACKET]     = { .call = nfulnl_recv_unsupp,
 873                                    .attr_count = NFULA_MAX, },
 874        [NFULNL_MSG_CONFIG]     = { .call = nfulnl_recv_config,
 875                                    .attr_count = NFULA_CFG_MAX,
 876                                    .policy = nfula_cfg_policy },
 877};
 878
 879static const struct nfnetlink_subsystem nfulnl_subsys = {
 880        .name           = "log",
 881        .subsys_id      = NFNL_SUBSYS_ULOG,
 882        .cb_count       = NFULNL_MSG_MAX,
 883        .cb             = nfulnl_cb,
 884};
 885
 886#ifdef CONFIG_PROC_FS
 887struct iter_state {
 888        unsigned int bucket;
 889};
 890
 891static struct hlist_node *get_first(struct iter_state *st)
 892{
 893        if (!st)
 894                return NULL;
 895
 896        for (st->bucket = 0; st->bucket < INSTANCE_BUCKETS; st->bucket++) {
 897                if (!hlist_empty(&instance_table[st->bucket]))
 898                        return rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 899        }
 900        return NULL;
 901}
 902
 903static struct hlist_node *get_next(struct iter_state *st, struct hlist_node *h)
 904{
 905        h = rcu_dereference_bh(hlist_next_rcu(h));
 906        while (!h) {
 907                if (++st->bucket >= INSTANCE_BUCKETS)
 908                        return NULL;
 909
 910                h = rcu_dereference_bh(hlist_first_rcu(&instance_table[st->bucket]));
 911        }
 912        return h;
 913}
 914
 915static struct hlist_node *get_idx(struct iter_state *st, loff_t pos)
 916{
 917        struct hlist_node *head;
 918        head = get_first(st);
 919
 920        if (head)
 921                while (pos && (head = get_next(st, head)))
 922                        pos--;
 923        return pos ? NULL : head;
 924}
 925
 926static void *seq_start(struct seq_file *seq, loff_t *pos)
 927        __acquires(rcu_bh)
 928{
 929        rcu_read_lock_bh();
 930        return get_idx(seq->private, *pos);
 931}
 932
 933static void *seq_next(struct seq_file *s, void *v, loff_t *pos)
 934{
 935        (*pos)++;
 936        return get_next(s->private, v);
 937}
 938
 939static void seq_stop(struct seq_file *s, void *v)
 940        __releases(rcu_bh)
 941{
 942        rcu_read_unlock_bh();
 943}
 944
 945static int seq_show(struct seq_file *s, void *v)
 946{
 947        const struct nfulnl_instance *inst = v;
 948
 949        return seq_printf(s, "%5d %6d %5d %1d %5d %6d %2d\n",
 950                          inst->group_num,
 951                          inst->peer_portid, inst->qlen,
 952                          inst->copy_mode, inst->copy_range,
 953                          inst->flushtimeout, atomic_read(&inst->use));
 954}
 955
 956static const struct seq_operations nful_seq_ops = {
 957        .start  = seq_start,
 958        .next   = seq_next,
 959        .stop   = seq_stop,
 960        .show   = seq_show,
 961};
 962
 963static int nful_open(struct inode *inode, struct file *file)
 964{
 965        return seq_open_private(file, &nful_seq_ops,
 966                        sizeof(struct iter_state));
 967}
 968
 969static const struct file_operations nful_file_ops = {
 970        .owner   = THIS_MODULE,
 971        .open    = nful_open,
 972        .read    = seq_read,
 973        .llseek  = seq_lseek,
 974        .release = seq_release_private,
 975};
 976
 977#endif /* PROC_FS */
 978
 979static int __init nfnetlink_log_init(void)
 980{
 981        int i, status = -ENOMEM;
 982
 983        for (i = 0; i < INSTANCE_BUCKETS; i++)
 984                INIT_HLIST_HEAD(&instance_table[i]);
 985
 986        /* it's not really all that important to have a random value, so
 987         * we can do this from the init function, even if there hasn't
 988         * been that much entropy yet */
 989        get_random_bytes(&hash_init, sizeof(hash_init));
 990
 991        netlink_register_notifier(&nfulnl_rtnl_notifier);
 992        status = nfnetlink_subsys_register(&nfulnl_subsys);
 993        if (status < 0) {
 994                printk(KERN_ERR "log: failed to create netlink socket\n");
 995                goto cleanup_netlink_notifier;
 996        }
 997
 998        status = nf_log_register(NFPROTO_UNSPEC, &nfulnl_logger);
 999        if (status < 0) {
1000                printk(KERN_ERR "log: failed to register logger\n");
1001                goto cleanup_subsys;
1002        }
1003
1004#ifdef CONFIG_PROC_FS
1005        if (!proc_create("nfnetlink_log", 0440,
1006                         proc_net_netfilter, &nful_file_ops)) {
1007                status = -ENOMEM;
1008                goto cleanup_logger;
1009        }
1010#endif
1011        return status;
1012
1013#ifdef CONFIG_PROC_FS
1014cleanup_logger:
1015        nf_log_unregister(&nfulnl_logger);
1016#endif
1017cleanup_subsys:
1018        nfnetlink_subsys_unregister(&nfulnl_subsys);
1019cleanup_netlink_notifier:
1020        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1021        return status;
1022}
1023
1024static void __exit nfnetlink_log_fini(void)
1025{
1026        nf_log_unregister(&nfulnl_logger);
1027#ifdef CONFIG_PROC_FS
1028        remove_proc_entry("nfnetlink_log", proc_net_netfilter);
1029#endif
1030        nfnetlink_subsys_unregister(&nfulnl_subsys);
1031        netlink_unregister_notifier(&nfulnl_rtnl_notifier);
1032}
1033
1034MODULE_DESCRIPTION("netfilter userspace logging");
1035MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
1036MODULE_LICENSE("GPL");
1037MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ULOG);
1038
1039module_init(nfnetlink_log_init);
1040module_exit(nfnetlink_log_fini);
1041
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