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ip_tables.c

/*
 * Packet matching code.
 *
 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/cache.h>
#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/kmod.h>
#include <linux/vmalloc.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <linux/icmp.h>
#include <net/ip.h>
#include <net/compat.h>
#include <asm/uaccess.h>
#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/err.h>
#include <linux/cpumask.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("IPv4 packet filter");

/*#define DEBUG_IP_FIREWALL*/
/*#define DEBUG_ALLOW_ALL*/ /* Useful for remote debugging */
/*#define DEBUG_IP_FIREWALL_USER*/

#ifdef DEBUG_IP_FIREWALL
#define dprintf(format, args...)  printk(format , ## args)
#else
#define dprintf(format, args...)
#endif

#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif

#ifdef CONFIG_NETFILTER_DEBUG
#define IP_NF_ASSERT(x)                               \
do {                                            \
      if (!(x))                                 \
            printk("IP_NF_ASSERT: %s:%s:%u\n",        \
                   __FUNCTION__, __FILE__, __LINE__); \
} while(0)
#else
#define IP_NF_ASSERT(x)
#endif

#if 0
/* All the better to debug you with... */
#define static
#define inline
#endif

/*
   We keep a set of rules for each CPU, so we can avoid write-locking
   them in the softirq when updating the counters and therefore
   only need to read-lock in the softirq; doing a write_lock_bh() in user
   context stops packets coming through and allows user context to read
   the counters or update the rules.

   Hence the start of any table is given by get_table() below.  */

/* Returns whether matches rule or not. */
static inline int
ip_packet_match(const struct iphdr *ip,
            const char *indev,
            const char *outdev,
            const struct ipt_ip *ipinfo,
            int isfrag)
{
      size_t i;
      unsigned long ret;

#define FWINV(bool,invflg) ((bool) ^ !!(ipinfo->invflags & invflg))

      if (FWINV((ip->saddr&ipinfo->smsk.s_addr) != ipinfo->src.s_addr,
              IPT_INV_SRCIP)
          || FWINV((ip->daddr&ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr,
                 IPT_INV_DSTIP)) {
            dprintf("Source or dest mismatch.\n");

            dprintf("SRC: %u.%u.%u.%u. Mask: %u.%u.%u.%u. Target: %u.%u.%u.%u.%s\n",
                  NIPQUAD(ip->saddr),
                  NIPQUAD(ipinfo->smsk.s_addr),
                  NIPQUAD(ipinfo->src.s_addr),
                  ipinfo->invflags & IPT_INV_SRCIP ? " (INV)" : "");
            dprintf("DST: %u.%u.%u.%u Mask: %u.%u.%u.%u Target: %u.%u.%u.%u.%s\n",
                  NIPQUAD(ip->daddr),
                  NIPQUAD(ipinfo->dmsk.s_addr),
                  NIPQUAD(ipinfo->dst.s_addr),
                  ipinfo->invflags & IPT_INV_DSTIP ? " (INV)" : "");
            return 0;
      }

      /* Look for ifname matches; this should unroll nicely. */
      for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
            ret |= (((const unsigned long *)indev)[i]
                  ^ ((const unsigned long *)ipinfo->iniface)[i])
                  & ((const unsigned long *)ipinfo->iniface_mask)[i];
      }

      if (FWINV(ret != 0, IPT_INV_VIA_IN)) {
            dprintf("VIA in mismatch (%s vs %s).%s\n",
                  indev, ipinfo->iniface,
                  ipinfo->invflags&IPT_INV_VIA_IN ?" (INV)":"");
            return 0;
      }

      for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned long); i++) {
            ret |= (((const unsigned long *)outdev)[i]
                  ^ ((const unsigned long *)ipinfo->outiface)[i])
                  & ((const unsigned long *)ipinfo->outiface_mask)[i];
      }

      if (FWINV(ret != 0, IPT_INV_VIA_OUT)) {
            dprintf("VIA out mismatch (%s vs %s).%s\n",
                  outdev, ipinfo->outiface,
                  ipinfo->invflags&IPT_INV_VIA_OUT ?" (INV)":"");
            return 0;
      }

      /* Check specific protocol */
      if (ipinfo->proto
          && FWINV(ip->protocol != ipinfo->proto, IPT_INV_PROTO)) {
            dprintf("Packet protocol %hi does not match %hi.%s\n",
                  ip->protocol, ipinfo->proto,
                  ipinfo->invflags&IPT_INV_PROTO ? " (INV)":"");
            return 0;
      }

      /* If we have a fragment rule but the packet is not a fragment
       * then we return zero */
      if (FWINV((ipinfo->flags&IPT_F_FRAG) && !isfrag, IPT_INV_FRAG)) {
            dprintf("Fragment rule but not fragment.%s\n",
                  ipinfo->invflags & IPT_INV_FRAG ? " (INV)" : "");
            return 0;
      }

      return 1;
}

static inline bool
ip_checkentry(const struct ipt_ip *ip)
{
      if (ip->flags & ~IPT_F_MASK) {
            duprintf("Unknown flag bits set: %08X\n",
                   ip->flags & ~IPT_F_MASK);
            return false;
      }
      if (ip->invflags & ~IPT_INV_MASK) {
            duprintf("Unknown invflag bits set: %08X\n",
                   ip->invflags & ~IPT_INV_MASK);
            return false;
      }
      return true;
}

static unsigned int
ipt_error(struct sk_buff *skb,
        const struct net_device *in,
        const struct net_device *out,
        unsigned int hooknum,
        const struct xt_target *target,
        const void *targinfo)
{
      if (net_ratelimit())
            printk("ip_tables: error: `%s'\n", (char *)targinfo);

      return NF_DROP;
}

static inline
bool do_match(struct ipt_entry_match *m,
            const struct sk_buff *skb,
            const struct net_device *in,
            const struct net_device *out,
            int offset,
            bool *hotdrop)
{
      /* Stop iteration if it doesn't match */
      if (!m->u.kernel.match->match(skb, in, out, m->u.kernel.match, m->data,
                              offset, ip_hdrlen(skb), hotdrop))
            return true;
      else
            return false;
}

static inline struct ipt_entry *
get_entry(void *base, unsigned int offset)
{
      return (struct ipt_entry *)(base + offset);
}

/* All zeroes == unconditional rule. */
static inline int
unconditional(const struct ipt_ip *ip)
{
      unsigned int i;

      for (i = 0; i < sizeof(*ip)/sizeof(__u32); i++)
            if (((__u32 *)ip)[i])
                  return 0;

      return 1;
}

#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
    defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
static const char *hooknames[] = {
      [NF_IP_PRE_ROUTING]           = "PREROUTING",
      [NF_IP_LOCAL_IN]        = "INPUT",
      [NF_IP_FORWARD]               = "FORWARD",
      [NF_IP_LOCAL_OUT]       = "OUTPUT",
      [NF_IP_POST_ROUTING]          = "POSTROUTING",
};

enum nf_ip_trace_comments {
      NF_IP_TRACE_COMMENT_RULE,
      NF_IP_TRACE_COMMENT_RETURN,
      NF_IP_TRACE_COMMENT_POLICY,
};

static const char *comments[] = {
      [NF_IP_TRACE_COMMENT_RULE]    = "rule",
      [NF_IP_TRACE_COMMENT_RETURN]  = "return",
      [NF_IP_TRACE_COMMENT_POLICY]  = "policy",
};

static struct nf_loginfo trace_loginfo = {
      .type = NF_LOG_TYPE_LOG,
      .u = {
            .log = {
                  .level = 4,
                  .logflags = NF_LOG_MASK,
            },
      },
};

static inline int
get_chainname_rulenum(struct ipt_entry *s, struct ipt_entry *e,
                  char *hookname, char **chainname,
                  char **comment, unsigned int *rulenum)
{
      struct ipt_standard_target *t = (void *)ipt_get_target(s);

      if (strcmp(t->target.u.kernel.target->name, IPT_ERROR_TARGET) == 0) {
            /* Head of user chain: ERROR target with chainname */
            *chainname = t->target.data;
            (*rulenum) = 0;
      } else if (s == e) {
            (*rulenum)++;

            if (s->target_offset == sizeof(struct ipt_entry)
               && strcmp(t->target.u.kernel.target->name,
                       IPT_STANDARD_TARGET) == 0
               && t->verdict < 0
               && unconditional(&s->ip)) {
                  /* Tail of chains: STANDARD target (return/policy) */
                  *comment = *chainname == hookname
                        ? (char *)comments[NF_IP_TRACE_COMMENT_POLICY]
                        : (char *)comments[NF_IP_TRACE_COMMENT_RETURN];
            }
            return 1;
      } else
            (*rulenum)++;

      return 0;
}

static void trace_packet(struct sk_buff *skb,
                   unsigned int hook,
                   const struct net_device *in,
                   const struct net_device *out,
                   char *tablename,
                   struct xt_table_info *private,
                   struct ipt_entry *e)
{
      void *table_base;
      struct ipt_entry *root;
      char *hookname, *chainname, *comment;
      unsigned int rulenum = 0;

      table_base = (void *)private->entries[smp_processor_id()];
      root = get_entry(table_base, private->hook_entry[hook]);

      hookname = chainname = (char *)hooknames[hook];
      comment = (char *)comments[NF_IP_TRACE_COMMENT_RULE];

      IPT_ENTRY_ITERATE(root,
                    private->size - private->hook_entry[hook],
                    get_chainname_rulenum,
                    e, hookname, &chainname, &comment, &rulenum);

      nf_log_packet(AF_INET, hook, skb, in, out, &trace_loginfo,
                  "TRACE: %s:%s:%s:%u ",
                  tablename, chainname, comment, rulenum);
}
#endif

/* Returns one of the generic firewall policies, like NF_ACCEPT. */
unsigned int
ipt_do_table(struct sk_buff *skb,
           unsigned int hook,
           const struct net_device *in,
           const struct net_device *out,
           struct xt_table *table)
{
      static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
      u_int16_t offset;
      struct iphdr *ip;
      u_int16_t datalen;
      bool hotdrop = false;
      /* Initializing verdict to NF_DROP keeps gcc happy. */
      unsigned int verdict = NF_DROP;
      const char *indev, *outdev;
      void *table_base;
      struct ipt_entry *e, *back;
      struct xt_table_info *private;

      /* Initialization */
      ip = ip_hdr(skb);
      datalen = skb->len - ip->ihl * 4;
      indev = in ? in->name : nulldevname;
      outdev = out ? out->name : nulldevname;
      /* We handle fragments by dealing with the first fragment as
       * if it was a normal packet.  All other fragments are treated
       * normally, except that they will NEVER match rules that ask
       * things we don't know, ie. tcp syn flag or ports).  If the
       * rule is also a fragment-specific rule, non-fragments won't
       * match it. */
      offset = ntohs(ip->frag_off) & IP_OFFSET;

      read_lock_bh(&table->lock);
      IP_NF_ASSERT(table->valid_hooks & (1 << hook));
      private = table->private;
      table_base = (void *)private->entries[smp_processor_id()];
      e = get_entry(table_base, private->hook_entry[hook]);

      /* For return from builtin chain */
      back = get_entry(table_base, private->underflow[hook]);

      do {
            IP_NF_ASSERT(e);
            IP_NF_ASSERT(back);
            if (ip_packet_match(ip, indev, outdev, &e->ip, offset)) {
                  struct ipt_entry_target *t;

                  if (IPT_MATCH_ITERATE(e, do_match,
                                    skb, in, out,
                                    offset, &hotdrop) != 0)
                        goto no_match;

                  ADD_COUNTER(e->counters, ntohs(ip->tot_len), 1);

                  t = ipt_get_target(e);
                  IP_NF_ASSERT(t->u.kernel.target);

#if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
    defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
                  /* The packet is traced: log it */
                  if (unlikely(skb->nf_trace))
                        trace_packet(skb, hook, in, out,
                                   table->name, private, e);
#endif
                  /* Standard target? */
                  if (!t->u.kernel.target->target) {
                        int v;

                        v = ((struct ipt_standard_target *)t)->verdict;
                        if (v < 0) {
                              /* Pop from stack? */
                              if (v != IPT_RETURN) {
                                    verdict = (unsigned)(-v) - 1;
                                    break;
                              }
                              e = back;
                              back = get_entry(table_base,
                                           back->comefrom);
                              continue;
                        }
                        if (table_base + v != (void *)e + e->next_offset
                            && !(e->ip.flags & IPT_F_GOTO)) {
                              /* Save old back ptr in next entry */
                              struct ipt_entry *next
                                    = (void *)e + e->next_offset;
                              next->comefrom
                                    = (void *)back - table_base;
                              /* set back pointer to next entry */
                              back = next;
                        }

                        e = get_entry(table_base, v);
                  } else {
                        /* Targets which reenter must return
                           abs. verdicts */
#ifdef CONFIG_NETFILTER_DEBUG
                        ((struct ipt_entry *)table_base)->comefrom
                              = 0xeeeeeeec;
#endif
                        verdict = t->u.kernel.target->target(skb,
                                                     in, out,
                                                     hook,
                                                     t->u.kernel.target,
                                                     t->data);

#ifdef CONFIG_NETFILTER_DEBUG
                        if (((struct ipt_entry *)table_base)->comefrom
                            != 0xeeeeeeec
                            && verdict == IPT_CONTINUE) {
                              printk("Target %s reentered!\n",
                                     t->u.kernel.target->name);
                              verdict = NF_DROP;
                        }
                        ((struct ipt_entry *)table_base)->comefrom
                              = 0x57acc001;
#endif
                        /* Target might have changed stuff. */
                        ip = ip_hdr(skb);
                        datalen = skb->len - ip->ihl * 4;

                        if (verdict == IPT_CONTINUE)
                              e = (void *)e + e->next_offset;
                        else
                              /* Verdict */
                              break;
                  }
            } else {

            no_match:
                  e = (void *)e + e->next_offset;
            }
      } while (!hotdrop);

      read_unlock_bh(&table->lock);

#ifdef DEBUG_ALLOW_ALL
      return NF_ACCEPT;
#else
      if (hotdrop)
            return NF_DROP;
      else return verdict;
#endif
}

/* Figures out from what hook each rule can be called: returns 0 if
   there are loops.  Puts hook bitmask in comefrom. */
static int
mark_source_chains(struct xt_table_info *newinfo,
               unsigned int valid_hooks, void *entry0)
{
      unsigned int hook;

      /* No recursion; use packet counter to save back ptrs (reset
         to 0 as we leave), and comefrom to save source hook bitmask */
      for (hook = 0; hook < NF_IP_NUMHOOKS; hook++) {
            unsigned int pos = newinfo->hook_entry[hook];
            struct ipt_entry *e
                  = (struct ipt_entry *)(entry0 + pos);

            if (!(valid_hooks & (1 << hook)))
                  continue;

            /* Set initial back pointer. */
            e->counters.pcnt = pos;

            for (;;) {
                  struct ipt_standard_target *t
                        = (void *)ipt_get_target(e);
                  int visited = e->comefrom & (1 << hook);

                  if (e->comefrom & (1 << NF_IP_NUMHOOKS)) {
                        printk("iptables: loop hook %u pos %u %08X.\n",
                               hook, pos, e->comefrom);
                        return 0;
                  }
                  e->comefrom
                        |= ((1 << hook) | (1 << NF_IP_NUMHOOKS));

                  /* Unconditional return/END. */
                  if ((e->target_offset == sizeof(struct ipt_entry)
                      && (strcmp(t->target.u.user.name,
                               IPT_STANDARD_TARGET) == 0)
                      && t->verdict < 0
                      && unconditional(&e->ip)) || visited) {
                        unsigned int oldpos, size;

                        if (t->verdict < -NF_MAX_VERDICT - 1) {
                              duprintf("mark_source_chains: bad "
                                    "negative verdict (%i)\n",
                                                t->verdict);
                              return 0;
                        }

                        /* Return: backtrack through the last
                           big jump. */
                        do {
                              e->comefrom ^= (1<<NF_IP_NUMHOOKS);
#ifdef DEBUG_IP_FIREWALL_USER
                              if (e->comefrom
                                  & (1 << NF_IP_NUMHOOKS)) {
                                    duprintf("Back unset "
                                           "on hook %u "
                                           "rule %u\n",
                                           hook, pos);
                              }
#endif
                              oldpos = pos;
                              pos = e->counters.pcnt;
                              e->counters.pcnt = 0;

                              /* We're at the start. */
                              if (pos == oldpos)
                                    goto next;

                              e = (struct ipt_entry *)
                                    (entry0 + pos);
                        } while (oldpos == pos + e->next_offset);

                        /* Move along one */
                        size = e->next_offset;
                        e = (struct ipt_entry *)
                              (entry0 + pos + size);
                        e->counters.pcnt = pos;
                        pos += size;
                  } else {
                        int newpos = t->verdict;

                        if (strcmp(t->target.u.user.name,
                                 IPT_STANDARD_TARGET) == 0
                            && newpos >= 0) {
                              if (newpos > newinfo->size -
                                    sizeof(struct ipt_entry)) {
                                    duprintf("mark_source_chains: "
                                          "bad verdict (%i)\n",
                                                newpos);
                                    return 0;
                              }
                              /* This a jump; chase it. */
                              duprintf("Jump rule %u -> %u\n",
                                     pos, newpos);
                        } else {
                              /* ... this is a fallthru */
                              newpos = pos + e->next_offset;
                        }
                        e = (struct ipt_entry *)
                              (entry0 + newpos);
                        e->counters.pcnt = pos;
                        pos = newpos;
                  }
            }
            next:
            duprintf("Finished chain %u\n", hook);
      }
      return 1;
}

static inline int
cleanup_match(struct ipt_entry_match *m, unsigned int *i)
{
      if (i && (*i)-- == 0)
            return 1;

      if (m->u.kernel.match->destroy)
            m->u.kernel.match->destroy(m->u.kernel.match, m->data);
      module_put(m->u.kernel.match->me);
      return 0;
}

static inline int
check_entry(struct ipt_entry *e, const char *name)
{
      struct ipt_entry_target *t;

      if (!ip_checkentry(&e->ip)) {
            duprintf("ip_tables: ip check failed %p %s.\n", e, name);
            return -EINVAL;
      }

      if (e->target_offset + sizeof(struct ipt_entry_target) > e->next_offset)
            return -EINVAL;

      t = ipt_get_target(e);
      if (e->target_offset + t->u.target_size > e->next_offset)
            return -EINVAL;

      return 0;
}

static inline int check_match(struct ipt_entry_match *m, const char *name,
                        const struct ipt_ip *ip, unsigned int hookmask,
                        unsigned int *i)
{
      struct xt_match *match;
      int ret;

      match = m->u.kernel.match;
      ret = xt_check_match(match, AF_INET, m->u.match_size - sizeof(*m),
                       name, hookmask, ip->proto,
                       ip->invflags & IPT_INV_PROTO);
      if (!ret && m->u.kernel.match->checkentry
          && !m->u.kernel.match->checkentry(name, ip, match, m->data,
                                    hookmask)) {
            duprintf("ip_tables: check failed for `%s'.\n",
                   m->u.kernel.match->name);
            ret = -EINVAL;
      }
      if (!ret)
            (*i)++;
      return ret;
}

static inline int
find_check_match(struct ipt_entry_match *m,
          const char *name,
          const struct ipt_ip *ip,
          unsigned int hookmask,
          unsigned int *i)
{
      struct xt_match *match;
      int ret;

      match = try_then_request_module(xt_find_match(AF_INET, m->u.user.name,
                                       m->u.user.revision),
                              "ipt_%s", m->u.user.name);
      if (IS_ERR(match) || !match) {
            duprintf("find_check_match: `%s' not found\n", m->u.user.name);
            return match ? PTR_ERR(match) : -ENOENT;
      }
      m->u.kernel.match = match;

      ret = check_match(m, name, ip, hookmask, i);
      if (ret)
            goto err;

      return 0;
err:
      module_put(m->u.kernel.match->me);
      return ret;
}

static inline int check_target(struct ipt_entry *e, const char *name)
{
      struct ipt_entry_target *t;
      struct xt_target *target;
      int ret;

      t = ipt_get_target(e);
      target = t->u.kernel.target;
      ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
                        name, e->comefrom, e->ip.proto,
                        e->ip.invflags & IPT_INV_PROTO);
      if (!ret && t->u.kernel.target->checkentry
               && !t->u.kernel.target->checkentry(name, e, target,
                                          t->data, e->comefrom)) {
            duprintf("ip_tables: check failed for `%s'.\n",
                   t->u.kernel.target->name);
            ret = -EINVAL;
      }
      return ret;
}

static inline int
find_check_entry(struct ipt_entry *e, const char *name, unsigned int size,
          unsigned int *i)
{
      struct ipt_entry_target *t;
      struct xt_target *target;
      int ret;
      unsigned int j;

      ret = check_entry(e, name);
      if (ret)
            return ret;

      j = 0;
      ret = IPT_MATCH_ITERATE(e, find_check_match, name, &e->ip,
                                          e->comefrom, &j);
      if (ret != 0)
            goto cleanup_matches;

      t = ipt_get_target(e);
      target = try_then_request_module(xt_find_target(AF_INET,
                                         t->u.user.name,
                                         t->u.user.revision),
                               "ipt_%s", t->u.user.name);
      if (IS_ERR(target) || !target) {
            duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
            ret = target ? PTR_ERR(target) : -ENOENT;
            goto cleanup_matches;
      }
      t->u.kernel.target = target;

      ret = check_target(e, name);
      if (ret)
            goto err;

      (*i)++;
      return 0;
 err:
      module_put(t->u.kernel.target->me);
 cleanup_matches:
      IPT_MATCH_ITERATE(e, cleanup_match, &j);
      return ret;
}

static inline int
check_entry_size_and_hooks(struct ipt_entry *e,
                     struct xt_table_info *newinfo,
                     unsigned char *base,
                     unsigned char *limit,
                     const unsigned int *hook_entries,
                     const unsigned int *underflows,
                     unsigned int *i)
{
      unsigned int h;

      if ((unsigned long)e % __alignof__(struct ipt_entry) != 0
          || (unsigned char *)e + sizeof(struct ipt_entry) >= limit) {
            duprintf("Bad offset %p\n", e);
            return -EINVAL;
      }

      if (e->next_offset
          < sizeof(struct ipt_entry) + sizeof(struct ipt_entry_target)) {
            duprintf("checking: element %p size %u\n",
                   e, e->next_offset);
            return -EINVAL;
      }

      /* Check hooks & underflows */
      for (h = 0; h < NF_IP_NUMHOOKS; h++) {
            if ((unsigned char *)e - base == hook_entries[h])
                  newinfo->hook_entry[h] = hook_entries[h];
            if ((unsigned char *)e - base == underflows[h])
                  newinfo->underflow[h] = underflows[h];
      }

      /* FIXME: underflows must be unconditional, standard verdicts
         < 0 (not IPT_RETURN). --RR */

      /* Clear counters and comefrom */
      e->counters = ((struct xt_counters) { 0, 0 });
      e->comefrom = 0;

      (*i)++;
      return 0;
}

static inline int
cleanup_entry(struct ipt_entry *e, unsigned int *i)
{
      struct ipt_entry_target *t;

      if (i && (*i)-- == 0)
            return 1;

      /* Cleanup all matches */
      IPT_MATCH_ITERATE(e, cleanup_match, NULL);
      t = ipt_get_target(e);
      if (t->u.kernel.target->destroy)
            t->u.kernel.target->destroy(t->u.kernel.target, t->data);
      module_put(t->u.kernel.target->me);
      return 0;
}

/* Checks and translates the user-supplied table segment (held in
   newinfo) */
static int
translate_table(const char *name,
            unsigned int valid_hooks,
            struct xt_table_info *newinfo,
            void *entry0,
            unsigned int size,
            unsigned int number,
            const unsigned int *hook_entries,
            const unsigned int *underflows)
{
      unsigned int i;
      int ret;

      newinfo->size = size;
      newinfo->number = number;

      /* Init all hooks to impossible value. */
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            newinfo->hook_entry[i] = 0xFFFFFFFF;
            newinfo->underflow[i] = 0xFFFFFFFF;
      }

      duprintf("translate_table: size %u\n", newinfo->size);
      i = 0;
      /* Walk through entries, checking offsets. */
      ret = IPT_ENTRY_ITERATE(entry0, newinfo->size,
                        check_entry_size_and_hooks,
                        newinfo,
                        entry0,
                        entry0 + size,
                        hook_entries, underflows, &i);
      if (ret != 0)
            return ret;

      if (i != number) {
            duprintf("translate_table: %u not %u entries\n",
                   i, number);
            return -EINVAL;
      }

      /* Check hooks all assigned */
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            /* Only hooks which are valid */
            if (!(valid_hooks & (1 << i)))
                  continue;
            if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
                  duprintf("Invalid hook entry %u %u\n",
                         i, hook_entries[i]);
                  return -EINVAL;
            }
            if (newinfo->underflow[i] == 0xFFFFFFFF) {
                  duprintf("Invalid underflow %u %u\n",
                         i, underflows[i]);
                  return -EINVAL;
            }
      }

      if (!mark_source_chains(newinfo, valid_hooks, entry0))
            return -ELOOP;

      /* Finally, each sanity check must pass */
      i = 0;
      ret = IPT_ENTRY_ITERATE(entry0, newinfo->size,
                        find_check_entry, name, size, &i);

      if (ret != 0) {
            IPT_ENTRY_ITERATE(entry0, newinfo->size,
                        cleanup_entry, &i);
            return ret;
      }

      /* And one copy for every other CPU */
      for_each_possible_cpu(i) {
            if (newinfo->entries[i] && newinfo->entries[i] != entry0)
                  memcpy(newinfo->entries[i], entry0, newinfo->size);
      }

      return ret;
}

/* Gets counters. */
static inline int
add_entry_to_counter(const struct ipt_entry *e,
                 struct xt_counters total[],
                 unsigned int *i)
{
      ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);

      (*i)++;
      return 0;
}

static inline int
set_entry_to_counter(const struct ipt_entry *e,
                 struct ipt_counters total[],
                 unsigned int *i)
{
      SET_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);

      (*i)++;
      return 0;
}

static void
get_counters(const struct xt_table_info *t,
           struct xt_counters counters[])
{
      unsigned int cpu;
      unsigned int i;
      unsigned int curcpu;

      /* Instead of clearing (by a previous call to memset())
       * the counters and using adds, we set the counters
       * with data used by 'current' CPU
       * We dont care about preemption here.
       */
      curcpu = raw_smp_processor_id();

      i = 0;
      IPT_ENTRY_ITERATE(t->entries[curcpu],
                    t->size,
                    set_entry_to_counter,
                    counters,
                    &i);

      for_each_possible_cpu(cpu) {
            if (cpu == curcpu)
                  continue;
            i = 0;
            IPT_ENTRY_ITERATE(t->entries[cpu],
                          t->size,
                          add_entry_to_counter,
                          counters,
                          &i);
      }
}

static inline struct xt_counters * alloc_counters(struct xt_table *table)
{
      unsigned int countersize;
      struct xt_counters *counters;
      struct xt_table_info *private = table->private;

      /* We need atomic snapshot of counters: rest doesn't change
         (other than comefrom, which userspace doesn't care
         about). */
      countersize = sizeof(struct xt_counters) * private->number;
      counters = vmalloc_node(countersize, numa_node_id());

      if (counters == NULL)
            return ERR_PTR(-ENOMEM);

      /* First, sum counters... */
      write_lock_bh(&table->lock);
      get_counters(private, counters);
      write_unlock_bh(&table->lock);

      return counters;
}

static int
copy_entries_to_user(unsigned int total_size,
                 struct xt_table *table,
                 void __user *userptr)
{
      unsigned int off, num;
      struct ipt_entry *e;
      struct xt_counters *counters;
      struct xt_table_info *private = table->private;
      int ret = 0;
      void *loc_cpu_entry;

      counters = alloc_counters(table);
      if (IS_ERR(counters))
            return PTR_ERR(counters);

      /* choose the copy that is on our node/cpu, ...
       * This choice is lazy (because current thread is
       * allowed to migrate to another cpu)
       */
      loc_cpu_entry = private->entries[raw_smp_processor_id()];
      /* ... then copy entire thing ... */
      if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
            ret = -EFAULT;
            goto free_counters;
      }

      /* FIXME: use iterator macros --RR */
      /* ... then go back and fix counters and names */
      for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
            unsigned int i;
            struct ipt_entry_match *m;
            struct ipt_entry_target *t;

            e = (struct ipt_entry *)(loc_cpu_entry + off);
            if (copy_to_user(userptr + off
                         + offsetof(struct ipt_entry, counters),
                         &counters[num],
                         sizeof(counters[num])) != 0) {
                  ret = -EFAULT;
                  goto free_counters;
            }

            for (i = sizeof(struct ipt_entry);
                 i < e->target_offset;
                 i += m->u.match_size) {
                  m = (void *)e + i;

                  if (copy_to_user(userptr + off + i
                               + offsetof(struct ipt_entry_match,
                                        u.user.name),
                               m->u.kernel.match->name,
                               strlen(m->u.kernel.match->name)+1)
                      != 0) {
                        ret = -EFAULT;
                        goto free_counters;
                  }
            }

            t = ipt_get_target(e);
            if (copy_to_user(userptr + off + e->target_offset
                         + offsetof(struct ipt_entry_target,
                                  u.user.name),
                         t->u.kernel.target->name,
                         strlen(t->u.kernel.target->name)+1) != 0) {
                  ret = -EFAULT;
                  goto free_counters;
            }
      }

 free_counters:
      vfree(counters);
      return ret;
}

#ifdef CONFIG_COMPAT
struct compat_delta {
      struct compat_delta *next;
      unsigned int offset;
      short delta;
};

static struct compat_delta *compat_offsets = NULL;

static int compat_add_offset(unsigned int offset, short delta)
{
      struct compat_delta *tmp;

      tmp = kmalloc(sizeof(struct compat_delta), GFP_KERNEL);
      if (!tmp)
            return -ENOMEM;
      tmp->offset = offset;
      tmp->delta = delta;
      if (compat_offsets) {
            tmp->next = compat_offsets->next;
            compat_offsets->next = tmp;
      } else {
            compat_offsets = tmp;
            tmp->next = NULL;
      }
      return 0;
}

static void compat_flush_offsets(void)
{
      struct compat_delta *tmp, *next;

      if (compat_offsets) {
            for(tmp = compat_offsets; tmp; tmp = next) {
                  next = tmp->next;
                  kfree(tmp);
            }
            compat_offsets = NULL;
      }
}

static short compat_calc_jump(unsigned int offset)
{
      struct compat_delta *tmp;
      short delta;

      for(tmp = compat_offsets, delta = 0; tmp; tmp = tmp->next)
            if (tmp->offset < offset)
                  delta += tmp->delta;
      return delta;
}

static void compat_standard_from_user(void *dst, void *src)
{
      int v = *(compat_int_t *)src;

      if (v > 0)
            v += compat_calc_jump(v);
      memcpy(dst, &v, sizeof(v));
}

static int compat_standard_to_user(void __user *dst, void *src)
{
      compat_int_t cv = *(int *)src;

      if (cv > 0)
            cv -= compat_calc_jump(cv);
      return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
}

static inline int
compat_calc_match(struct ipt_entry_match *m, int * size)
{
      *size += xt_compat_match_offset(m->u.kernel.match);
      return 0;
}

static int compat_calc_entry(struct ipt_entry *e, struct xt_table_info *info,
            void *base, struct xt_table_info *newinfo)
{
      struct ipt_entry_target *t;
      unsigned int entry_offset;
      int off, i, ret;

      off = 0;
      entry_offset = (void *)e - base;
      IPT_MATCH_ITERATE(e, compat_calc_match, &off);
      t = ipt_get_target(e);
      off += xt_compat_target_offset(t->u.kernel.target);
      newinfo->size -= off;
      ret = compat_add_offset(entry_offset, off);
      if (ret)
            return ret;

      for (i = 0; i< NF_IP_NUMHOOKS; i++) {
            if (info->hook_entry[i] && (e < (struct ipt_entry *)
                        (base + info->hook_entry[i])))
                  newinfo->hook_entry[i] -= off;
            if (info->underflow[i] && (e < (struct ipt_entry *)
                        (base + info->underflow[i])))
                  newinfo->underflow[i] -= off;
      }
      return 0;
}

static int compat_table_info(struct xt_table_info *info,
            struct xt_table_info *newinfo)
{
      void *loc_cpu_entry;
      int i;

      if (!newinfo || !info)
            return -EINVAL;

      memset(newinfo, 0, sizeof(struct xt_table_info));
      newinfo->size = info->size;
      newinfo->number = info->number;
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            newinfo->hook_entry[i] = info->hook_entry[i];
            newinfo->underflow[i] = info->underflow[i];
      }
      loc_cpu_entry = info->entries[raw_smp_processor_id()];
      return IPT_ENTRY_ITERATE(loc_cpu_entry, info->size,
                  compat_calc_entry, info, loc_cpu_entry, newinfo);
}
#endif

static int get_info(void __user *user, int *len, int compat)
{
      char name[IPT_TABLE_MAXNAMELEN];
      struct xt_table *t;
      int ret;

      if (*len != sizeof(struct ipt_getinfo)) {
            duprintf("length %u != %u\n", *len,
                  (unsigned int)sizeof(struct ipt_getinfo));
            return -EINVAL;
      }

      if (copy_from_user(name, user, sizeof(name)) != 0)
            return -EFAULT;

      name[IPT_TABLE_MAXNAMELEN-1] = '\0';
#ifdef CONFIG_COMPAT
      if (compat)
            xt_compat_lock(AF_INET);
#endif
      t = try_then_request_module(xt_find_table_lock(AF_INET, name),
                  "iptable_%s", name);
      if (t && !IS_ERR(t)) {
            struct ipt_getinfo info;
            struct xt_table_info *private = t->private;

#ifdef CONFIG_COMPAT
            if (compat) {
                  struct xt_table_info tmp;
                  ret = compat_table_info(private, &tmp);
                  compat_flush_offsets();
                  private =  &tmp;
            }
#endif
            info.valid_hooks = t->valid_hooks;
            memcpy(info.hook_entry, private->hook_entry,
                        sizeof(info.hook_entry));
            memcpy(info.underflow, private->underflow,
                        sizeof(info.underflow));
            info.num_entries = private->number;
            info.size = private->size;
            strcpy(info.name, name);

            if (copy_to_user(user, &info, *len) != 0)
                  ret = -EFAULT;
            else
                  ret = 0;

            xt_table_unlock(t);
            module_put(t->me);
      } else
            ret = t ? PTR_ERR(t) : -ENOENT;
#ifdef CONFIG_COMPAT
      if (compat)
            xt_compat_unlock(AF_INET);
#endif
      return ret;
}

static int
get_entries(struct ipt_get_entries __user *uptr, int *len)
{
      int ret;
      struct ipt_get_entries get;
      struct xt_table *t;

      if (*len < sizeof(get)) {
            duprintf("get_entries: %u < %d\n", *len,
                        (unsigned int)sizeof(get));
            return -EINVAL;
      }
      if (copy_from_user(&get, uptr, sizeof(get)) != 0)
            return -EFAULT;
      if (*len != sizeof(struct ipt_get_entries) + get.size) {
            duprintf("get_entries: %u != %u\n", *len,
                        (unsigned int)(sizeof(struct ipt_get_entries) +
                        get.size));
            return -EINVAL;
      }

      t = xt_find_table_lock(AF_INET, get.name);
      if (t && !IS_ERR(t)) {
            struct xt_table_info *private = t->private;
            duprintf("t->private->number = %u\n",
                   private->number);
            if (get.size == private->size)
                  ret = copy_entries_to_user(private->size,
                                       t, uptr->entrytable);
            else {
                  duprintf("get_entries: I've got %u not %u!\n",
                         private->size,
                         get.size);
                  ret = -EINVAL;
            }
            module_put(t->me);
            xt_table_unlock(t);
      } else
            ret = t ? PTR_ERR(t) : -ENOENT;

      return ret;
}

static int
__do_replace(const char *name, unsigned int valid_hooks,
            struct xt_table_info *newinfo, unsigned int num_counters,
            void __user *counters_ptr)
{
      int ret;
      struct xt_table *t;
      struct xt_table_info *oldinfo;
      struct xt_counters *counters;
      void *loc_cpu_old_entry;

      ret = 0;
      counters = vmalloc(num_counters * sizeof(struct xt_counters));
      if (!counters) {
            ret = -ENOMEM;
            goto out;
      }

      t = try_then_request_module(xt_find_table_lock(AF_INET, name),
                            "iptable_%s", name);
      if (!t || IS_ERR(t)) {
            ret = t ? PTR_ERR(t) : -ENOENT;
            goto free_newinfo_counters_untrans;
      }

      /* You lied! */
      if (valid_hooks != t->valid_hooks) {
            duprintf("Valid hook crap: %08X vs %08X\n",
                   valid_hooks, t->valid_hooks);
            ret = -EINVAL;
            goto put_module;
      }

      oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
      if (!oldinfo)
            goto put_module;

      /* Update module usage count based on number of rules */
      duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
            oldinfo->number, oldinfo->initial_entries, newinfo->number);
      if ((oldinfo->number > oldinfo->initial_entries) ||
          (newinfo->number <= oldinfo->initial_entries))
            module_put(t->me);
      if ((oldinfo->number > oldinfo->initial_entries) &&
          (newinfo->number <= oldinfo->initial_entries))
            module_put(t->me);

      /* Get the old counters. */
      get_counters(oldinfo, counters);
      /* Decrease module usage counts and free resource */
      loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
      IPT_ENTRY_ITERATE(loc_cpu_old_entry, oldinfo->size, cleanup_entry,NULL);
      xt_free_table_info(oldinfo);
      if (copy_to_user(counters_ptr, counters,
                   sizeof(struct xt_counters) * num_counters) != 0)
            ret = -EFAULT;
      vfree(counters);
      xt_table_unlock(t);
      return ret;

 put_module:
      module_put(t->me);
      xt_table_unlock(t);
 free_newinfo_counters_untrans:
      vfree(counters);
 out:
      return ret;
}

static int
do_replace(void __user *user, unsigned int len)
{
      int ret;
      struct ipt_replace tmp;
      struct xt_table_info *newinfo;
      void *loc_cpu_entry;

      if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
            return -EFAULT;

      /* Hack: Causes ipchains to give correct error msg --RR */
      if (len != sizeof(tmp) + tmp.size)
            return -ENOPROTOOPT;

      /* overflow check */
      if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
                  SMP_CACHE_BYTES)
            return -ENOMEM;
      if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
            return -ENOMEM;

      newinfo = xt_alloc_table_info(tmp.size);
      if (!newinfo)
            return -ENOMEM;

      /* choose the copy that is our node/cpu */
      loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
      if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
                     tmp.size) != 0) {
            ret = -EFAULT;
            goto free_newinfo;
      }

      ret = translate_table(tmp.name, tmp.valid_hooks,
                        newinfo, loc_cpu_entry, tmp.size, tmp.num_entries,
                        tmp.hook_entry, tmp.underflow);
      if (ret != 0)
            goto free_newinfo;

      duprintf("ip_tables: Translated table\n");

      ret = __do_replace(tmp.name, tmp.valid_hooks,
                        newinfo, tmp.num_counters,
                        tmp.counters);
      if (ret)
            goto free_newinfo_untrans;
      return 0;

 free_newinfo_untrans:
      IPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry,NULL);
 free_newinfo:
      xt_free_table_info(newinfo);
      return ret;
}

/* We're lazy, and add to the first CPU; overflow works its fey magic
 * and everything is OK. */
static inline int
add_counter_to_entry(struct ipt_entry *e,
                 const struct xt_counters addme[],
                 unsigned int *i)
{
#if 0
      duprintf("add_counter: Entry %u %lu/%lu + %lu/%lu\n",
             *i,
             (long unsigned int)e->counters.pcnt,
             (long unsigned int)e->counters.bcnt,
             (long unsigned int)addme[*i].pcnt,
             (long unsigned int)addme[*i].bcnt);
#endif

      ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);

      (*i)++;
      return 0;
}

static int
do_add_counters(void __user *user, unsigned int len, int compat)
{
      unsigned int i;
      struct xt_counters_info tmp;
      struct xt_counters *paddc;
      unsigned int num_counters;
      char *name;
      int size;
      void *ptmp;
      struct xt_table *t;
      struct xt_table_info *private;
      int ret = 0;
      void *loc_cpu_entry;
#ifdef CONFIG_COMPAT
      struct compat_xt_counters_info compat_tmp;

      if (compat) {
            ptmp = &compat_tmp;
            size = sizeof(struct compat_xt_counters_info);
      } else
#endif
      {
            ptmp = &tmp;
            size = sizeof(struct xt_counters_info);
      }

      if (copy_from_user(ptmp, user, size) != 0)
            return -EFAULT;

#ifdef CONFIG_COMPAT
      if (compat) {
            num_counters = compat_tmp.num_counters;
            name = compat_tmp.name;
      } else
#endif
      {
            num_counters = tmp.num_counters;
            name = tmp.name;
      }

      if (len != size + num_counters * sizeof(struct xt_counters))
            return -EINVAL;

      paddc = vmalloc_node(len - size, numa_node_id());
      if (!paddc)
            return -ENOMEM;

      if (copy_from_user(paddc, user + size, len - size) != 0) {
            ret = -EFAULT;
            goto free;
      }

      t = xt_find_table_lock(AF_INET, name);
      if (!t || IS_ERR(t)) {
            ret = t ? PTR_ERR(t) : -ENOENT;
            goto free;
      }

      write_lock_bh(&t->lock);
      private = t->private;
      if (private->number != num_counters) {
            ret = -EINVAL;
            goto unlock_up_free;
      }

      i = 0;
      /* Choose the copy that is on our node */
      loc_cpu_entry = private->entries[raw_smp_processor_id()];
      IPT_ENTRY_ITERATE(loc_cpu_entry,
                    private->size,
                    add_counter_to_entry,
                    paddc,
                    &i);
 unlock_up_free:
      write_unlock_bh(&t->lock);
      xt_table_unlock(t);
      module_put(t->me);
 free:
      vfree(paddc);

      return ret;
}

#ifdef CONFIG_COMPAT
struct compat_ipt_replace {
      char              name[IPT_TABLE_MAXNAMELEN];
      u32               valid_hooks;
      u32               num_entries;
      u32               size;
      u32               hook_entry[NF_IP_NUMHOOKS];
      u32               underflow[NF_IP_NUMHOOKS];
      u32               num_counters;
      compat_uptr_t           counters;   /* struct ipt_counters * */
      struct compat_ipt_entry entries[0];
};

static inline int compat_copy_match_to_user(struct ipt_entry_match *m,
            void __user **dstptr, compat_uint_t *size)
{
      return xt_compat_match_to_user(m, dstptr, size);
}

static int
compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
                    compat_uint_t *size, struct xt_counters *counters,
                    unsigned int *i)
{
      struct ipt_entry_target *t;
      struct compat_ipt_entry __user *ce;
      u_int16_t target_offset, next_offset;
      compat_uint_t origsize;
      int ret;

      ret = -EFAULT;
      origsize = *size;
      ce = (struct compat_ipt_entry __user *)*dstptr;
      if (copy_to_user(ce, e, sizeof(struct ipt_entry)))
            goto out;

      if (copy_to_user(&ce->counters, &counters[*i], sizeof(counters[*i])))
            goto out;

      *dstptr += sizeof(struct compat_ipt_entry);
      ret = IPT_MATCH_ITERATE(e, compat_copy_match_to_user, dstptr, size);
      target_offset = e->target_offset - (origsize - *size);
      if (ret)
            goto out;
      t = ipt_get_target(e);
      ret = xt_compat_target_to_user(t, dstptr, size);
      if (ret)
            goto out;
      ret = -EFAULT;
      next_offset = e->next_offset - (origsize - *size);
      if (put_user(target_offset, &ce->target_offset))
            goto out;
      if (put_user(next_offset, &ce->next_offset))
            goto out;

      (*i)++;
      return 0;
out:
      return ret;
}

static inline int
compat_find_calc_match(struct ipt_entry_match *m,
          const char *name,
          const struct ipt_ip *ip,
          unsigned int hookmask,
          int *size, int *i)
{
      struct xt_match *match;

      match = try_then_request_module(xt_find_match(AF_INET, m->u.user.name,
                                       m->u.user.revision),
                              "ipt_%s", m->u.user.name);
      if (IS_ERR(match) || !match) {
            duprintf("compat_check_calc_match: `%s' not found\n",
                        m->u.user.name);
            return match ? PTR_ERR(match) : -ENOENT;
      }
      m->u.kernel.match = match;
      *size += xt_compat_match_offset(match);

      (*i)++;
      return 0;
}

static inline int
compat_release_match(struct ipt_entry_match *m, unsigned int *i)
{
      if (i && (*i)-- == 0)
            return 1;

      module_put(m->u.kernel.match->me);
      return 0;
}

static inline int
compat_release_entry(struct ipt_entry *e, unsigned int *i)
{
      struct ipt_entry_target *t;

      if (i && (*i)-- == 0)
            return 1;

      /* Cleanup all matches */
      IPT_MATCH_ITERATE(e, compat_release_match, NULL);
      t = ipt_get_target(e);
      module_put(t->u.kernel.target->me);
      return 0;
}

static inline int
check_compat_entry_size_and_hooks(struct ipt_entry *e,
                     struct xt_table_info *newinfo,
                     unsigned int *size,
                     unsigned char *base,
                     unsigned char *limit,
                     unsigned int *hook_entries,
                     unsigned int *underflows,
                     unsigned int *i,
                     const char *name)
{
      struct ipt_entry_target *t;
      struct xt_target *target;
      unsigned int entry_offset;
      int ret, off, h, j;

      duprintf("check_compat_entry_size_and_hooks %p\n", e);
      if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0
          || (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit) {
            duprintf("Bad offset %p, limit = %p\n", e, limit);
            return -EINVAL;
      }

      if (e->next_offset < sizeof(struct compat_ipt_entry) +
                  sizeof(struct compat_xt_entry_target)) {
            duprintf("checking: element %p size %u\n",
                   e, e->next_offset);
            return -EINVAL;
      }

      ret = check_entry(e, name);
      if (ret)
            return ret;

      off = 0;
      entry_offset = (void *)e - (void *)base;
      j = 0;
      ret = IPT_MATCH_ITERATE(e, compat_find_calc_match, name, &e->ip,
                  e->comefrom, &off, &j);
      if (ret != 0)
            goto release_matches;

      t = ipt_get_target(e);
      target = try_then_request_module(xt_find_target(AF_INET,
                                         t->u.user.name,
                                         t->u.user.revision),
                               "ipt_%s", t->u.user.name);
      if (IS_ERR(target) || !target) {
            duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
                                          t->u.user.name);
            ret = target ? PTR_ERR(target) : -ENOENT;
            goto release_matches;
      }
      t->u.kernel.target = target;

      off += xt_compat_target_offset(target);
      *size += off;
      ret = compat_add_offset(entry_offset, off);
      if (ret)
            goto out;

      /* Check hooks & underflows */
      for (h = 0; h < NF_IP_NUMHOOKS; h++) {
            if ((unsigned char *)e - base == hook_entries[h])
                  newinfo->hook_entry[h] = hook_entries[h];
            if ((unsigned char *)e - base == underflows[h])
                  newinfo->underflow[h] = underflows[h];
      }

      /* Clear counters and comefrom */
      e->counters = ((struct ipt_counters) { 0, 0 });
      e->comefrom = 0;

      (*i)++;
      return 0;

out:
      module_put(t->u.kernel.target->me);
release_matches:
      IPT_MATCH_ITERATE(e, compat_release_match, &j);
      return ret;
}

static inline int compat_copy_match_from_user(struct ipt_entry_match *m,
      void **dstptr, compat_uint_t *size, const char *name,
      const struct ipt_ip *ip, unsigned int hookmask)
{
      xt_compat_match_from_user(m, dstptr, size);
      return 0;
}

static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
      unsigned int *size, const char *name,
      struct xt_table_info *newinfo, unsigned char *base)
{
      struct ipt_entry_target *t;
      struct xt_target *target;
      struct ipt_entry *de;
      unsigned int origsize;
      int ret, h;

      ret = 0;
      origsize = *size;
      de = (struct ipt_entry *)*dstptr;
      memcpy(de, e, sizeof(struct ipt_entry));

      *dstptr += sizeof(struct compat_ipt_entry);
      ret = IPT_MATCH_ITERATE(e, compat_copy_match_from_user, dstptr, size,
                  name, &de->ip, de->comefrom);
      if (ret)
            return ret;
      de->target_offset = e->target_offset - (origsize - *size);
      t = ipt_get_target(e);
      target = t->u.kernel.target;
      xt_compat_target_from_user(t, dstptr, size);

      de->next_offset = e->next_offset - (origsize - *size);
      for (h = 0; h < NF_IP_NUMHOOKS; h++) {
            if ((unsigned char *)de - base < newinfo->hook_entry[h])
                  newinfo->hook_entry[h] -= origsize - *size;
            if ((unsigned char *)de - base < newinfo->underflow[h])
                  newinfo->underflow[h] -= origsize - *size;
      }
      return ret;
}

static inline int compat_check_entry(struct ipt_entry *e, const char *name,
                                    unsigned int *i)
{
      int j, ret;

      j = 0;
      ret = IPT_MATCH_ITERATE(e, check_match, name, &e->ip, e->comefrom, &j);
      if (ret)
            goto cleanup_matches;

      ret = check_target(e, name);
      if (ret)
            goto cleanup_matches;

      (*i)++;
      return 0;

 cleanup_matches:
      IPT_MATCH_ITERATE(e, cleanup_match, &j);
      return ret;
}

static int
translate_compat_table(const char *name,
            unsigned int valid_hooks,
            struct xt_table_info **pinfo,
            void **pentry0,
            unsigned int total_size,
            unsigned int number,
            unsigned int *hook_entries,
            unsigned int *underflows)
{
      unsigned int i, j;
      struct xt_table_info *newinfo, *info;
      void *pos, *entry0, *entry1;
      unsigned int size;
      int ret;

      info = *pinfo;
      entry0 = *pentry0;
      size = total_size;
      info->number = number;

      /* Init all hooks to impossible value. */
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            info->hook_entry[i] = 0xFFFFFFFF;
            info->underflow[i] = 0xFFFFFFFF;
      }

      duprintf("translate_compat_table: size %u\n", info->size);
      j = 0;
      xt_compat_lock(AF_INET);
      /* Walk through entries, checking offsets. */
      ret = IPT_ENTRY_ITERATE(entry0, total_size,
                        check_compat_entry_size_and_hooks,
                        info, &size, entry0,
                        entry0 + total_size,
                        hook_entries, underflows, &j, name);
      if (ret != 0)
            goto out_unlock;

      ret = -EINVAL;
      if (j != number) {
            duprintf("translate_compat_table: %u not %u entries\n",
                   j, number);
            goto out_unlock;
      }

      /* Check hooks all assigned */
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            /* Only hooks which are valid */
            if (!(valid_hooks & (1 << i)))
                  continue;
            if (info->hook_entry[i] == 0xFFFFFFFF) {
                  duprintf("Invalid hook entry %u %u\n",
                         i, hook_entries[i]);
                  goto out_unlock;
            }
            if (info->underflow[i] == 0xFFFFFFFF) {
                  duprintf("Invalid underflow %u %u\n",
                         i, underflows[i]);
                  goto out_unlock;
            }
      }

      ret = -ENOMEM;
      newinfo = xt_alloc_table_info(size);
      if (!newinfo)
            goto out_unlock;

      newinfo->number = number;
      for (i = 0; i < NF_IP_NUMHOOKS; i++) {
            newinfo->hook_entry[i] = info->hook_entry[i];
            newinfo->underflow[i] = info->underflow[i];
      }
      entry1 = newinfo->entries[raw_smp_processor_id()];
      pos = entry1;
      size =  total_size;
      ret = IPT_ENTRY_ITERATE(entry0, total_size,
                  compat_copy_entry_from_user, &pos, &size,
                  name, newinfo, entry1);
      compat_flush_offsets();
      xt_compat_unlock(AF_INET);
      if (ret)
            goto free_newinfo;

      ret = -ELOOP;
      if (!mark_source_chains(newinfo, valid_hooks, entry1))
            goto free_newinfo;

      i = 0;
      ret = IPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
                                                name, &i);
      if (ret) {
            j -= i;
            IPT_ENTRY_ITERATE_CONTINUE(entry1, newinfo->size, i,
                                    compat_release_entry, &j);
            IPT_ENTRY_ITERATE(entry1, newinfo->size, cleanup_entry, &i);
            xt_free_table_info(newinfo);
            return ret;
      }

      /* And one copy for every other CPU */
      for_each_possible_cpu(i)
            if (newinfo->entries[i] && newinfo->entries[i] != entry1)
                  memcpy(newinfo->entries[i], entry1, newinfo->size);

      *pinfo = newinfo;
      *pentry0 = entry1;
      xt_free_table_info(info);
      return 0;

free_newinfo:
      xt_free_table_info(newinfo);
out:
      IPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
      return ret;
out_unlock:
      compat_flush_offsets();
      xt_compat_unlock(AF_INET);
      goto out;
}

static int
compat_do_replace(void __user *user, unsigned int len)
{
      int ret;
      struct compat_ipt_replace tmp;
      struct xt_table_info *newinfo;
      void *loc_cpu_entry;

      if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
            return -EFAULT;

      /* Hack: Causes ipchains to give correct error msg --RR */
      if (len != sizeof(tmp) + tmp.size)
            return -ENOPROTOOPT;

      /* overflow check */
      if (tmp.size >= (INT_MAX - sizeof(struct xt_table_info)) / NR_CPUS -
                  SMP_CACHE_BYTES)
            return -ENOMEM;
      if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
            return -ENOMEM;

      newinfo = xt_alloc_table_info(tmp.size);
      if (!newinfo)
            return -ENOMEM;

      /* choose the copy that is our node/cpu */
      loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
      if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
                     tmp.size) != 0) {
            ret = -EFAULT;
            goto free_newinfo;
      }

      ret = translate_compat_table(tmp.name, tmp.valid_hooks,
                        &newinfo, &loc_cpu_entry, tmp.size,
                        tmp.num_entries, tmp.hook_entry, tmp.underflow);
      if (ret != 0)
            goto free_newinfo;

      duprintf("compat_do_replace: Translated table\n");

      ret = __do_replace(tmp.name, tmp.valid_hooks,
                        newinfo, tmp.num_counters,
                        compat_ptr(tmp.counters));
      if (ret)
            goto free_newinfo_untrans;
      return 0;

 free_newinfo_untrans:
      IPT_ENTRY_ITERATE(loc_cpu_entry, newinfo->size, cleanup_entry,NULL);
 free_newinfo:
      xt_free_table_info(newinfo);
      return ret;
}

static int
compat_do_ipt_set_ctl(struct sock *sk,    int cmd, void __user *user,
            unsigned int len)
{
      int ret;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      switch (cmd) {
      case IPT_SO_SET_REPLACE:
            ret = compat_do_replace(user, len);
            break;

      case IPT_SO_SET_ADD_COUNTERS:
            ret = do_add_counters(user, len, 1);
            break;

      default:
            duprintf("do_ipt_set_ctl:  unknown request %i\n", cmd);
            ret = -EINVAL;
      }

      return ret;
}

struct compat_ipt_get_entries
{
      char name[IPT_TABLE_MAXNAMELEN];
      compat_uint_t size;
      struct compat_ipt_entry entrytable[0];
};

static int compat_copy_entries_to_user(unsigned int total_size,
                 struct xt_table *table, void __user *userptr)
{
      struct xt_counters *counters;
      struct xt_table_info *private = table->private;
      void __user *pos;
      unsigned int size;
      int ret = 0;
      void *loc_cpu_entry;
      unsigned int i = 0;

      counters = alloc_counters(table);
      if (IS_ERR(counters))
            return PTR_ERR(counters);

      /* choose the copy that is on our node/cpu, ...
       * This choice is lazy (because current thread is
       * allowed to migrate to another cpu)
       */
      loc_cpu_entry = private->entries[raw_smp_processor_id()];
      pos = userptr;
      size = total_size;
      ret = IPT_ENTRY_ITERATE(loc_cpu_entry, total_size,
                        compat_copy_entry_to_user,
                        &pos, &size, counters, &i);

      vfree(counters);
      return ret;
}

static int
compat_get_entries(struct compat_ipt_get_entries __user *uptr, int *len)
{
      int ret;
      struct compat_ipt_get_entries get;
      struct xt_table *t;


      if (*len < sizeof(get)) {
            duprintf("compat_get_entries: %u < %u\n",
                        *len, (unsigned int)sizeof(get));
            return -EINVAL;
      }

      if (copy_from_user(&get, uptr, sizeof(get)) != 0)
            return -EFAULT;

      if (*len != sizeof(struct compat_ipt_get_entries) + get.size) {
            duprintf("compat_get_entries: %u != %u\n", *len,
                  (unsigned int)(sizeof(struct compat_ipt_get_entries) +
                  get.size));
            return -EINVAL;
      }

      xt_compat_lock(AF_INET);
      t = xt_find_table_lock(AF_INET, get.name);
      if (t && !IS_ERR(t)) {
            struct xt_table_info *private = t->private;
            struct xt_table_info info;
            duprintf("t->private->number = %u\n",
                   private->number);
            ret = compat_table_info(private, &info);
            if (!ret && get.size == info.size) {
                  ret = compat_copy_entries_to_user(private->size,
                                       t, uptr->entrytable);
            } else if (!ret) {
                  duprintf("compat_get_entries: I've got %u not %u!\n",
                         private->size,
                         get.size);
                  ret = -EINVAL;
            }
            compat_flush_offsets();
            module_put(t->me);
            xt_table_unlock(t);
      } else
            ret = t ? PTR_ERR(t) : -ENOENT;

      xt_compat_unlock(AF_INET);
      return ret;
}

static int do_ipt_get_ctl(struct sock *, int, void __user *, int *);

static int
compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
{
      int ret;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      switch (cmd) {
      case IPT_SO_GET_INFO:
            ret = get_info(user, len, 1);
            break;
      case IPT_SO_GET_ENTRIES:
            ret = compat_get_entries(user, len);
            break;
      default:
            ret = do_ipt_get_ctl(sk, cmd, user, len);
      }
      return ret;
}
#endif

static int
do_ipt_set_ctl(struct sock *sk,     int cmd, void __user *user, unsigned int len)
{
      int ret;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      switch (cmd) {
      case IPT_SO_SET_REPLACE:
            ret = do_replace(user, len);
            break;

      case IPT_SO_SET_ADD_COUNTERS:
            ret = do_add_counters(user, len, 0);
            break;

      default:
            duprintf("do_ipt_set_ctl:  unknown request %i\n", cmd);
            ret = -EINVAL;
      }

      return ret;
}

static int
do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
{
      int ret;

      if (!capable(CAP_NET_ADMIN))
            return -EPERM;

      switch (cmd) {
      case IPT_SO_GET_INFO:
            ret = get_info(user, len, 0);
            break;

      case IPT_SO_GET_ENTRIES:
            ret = get_entries(user, len);
            break;

      case IPT_SO_GET_REVISION_MATCH:
      case IPT_SO_GET_REVISION_TARGET: {
            struct ipt_get_revision rev;
            int target;

            if (*len != sizeof(rev)) {
                  ret = -EINVAL;
                  break;
            }
            if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
                  ret = -EFAULT;
                  break;
            }

            if (cmd == IPT_SO_GET_REVISION_TARGET)
                  target = 1;
            else
                  target = 0;

            try_then_request_module(xt_find_revision(AF_INET, rev.name,
                                           rev.revision,
                                           target, &ret),
                              "ipt_%s", rev.name);
            break;
      }

      default:
            duprintf("do_ipt_get_ctl: unknown request %i\n", cmd);
            ret = -EINVAL;
      }

      return ret;
}

int ipt_register_table(struct xt_table *table, const struct ipt_replace *repl)
{
      int ret;
      struct xt_table_info *newinfo;
      static struct xt_table_info bootstrap
            = { 0, 0, 0, { 0 }, { 0 }, { } };
      void *loc_cpu_entry;

      newinfo = xt_alloc_table_info(repl->size);
      if (!newinfo)
            return -ENOMEM;

      /* choose the copy on our node/cpu
       * but dont care of preemption
       */
      loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
      memcpy(loc_cpu_entry, repl->entries, repl->size);

      ret = translate_table(table->name, table->valid_hooks,
                        newinfo, loc_cpu_entry, repl->size,
                        repl->num_entries,
                        repl->hook_entry,
                        repl->underflow);
      if (ret != 0) {
            xt_free_table_info(newinfo);
            return ret;
      }

      ret = xt_register_table(table, &bootstrap, newinfo);
      if (ret != 0) {
            xt_free_table_info(newinfo);
            return ret;
      }

      return 0;
}

void ipt_unregister_table(struct xt_table *table)
{
      struct xt_table_info *private;
      void *loc_cpu_entry;

      private = xt_unregister_table(table);

      /* Decrease module usage counts and free resources */
      loc_cpu_entry = private->entries[raw_smp_processor_id()];
      IPT_ENTRY_ITERATE(loc_cpu_entry, private->size, cleanup_entry, NULL);
      xt_free_table_info(private);
}

/* Returns 1 if the type and code is matched by the range, 0 otherwise */
static inline bool
icmp_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
                 u_int8_t type, u_int8_t code,
                 bool invert)
{
      return ((test_type == 0xFF) || (type == test_type && code >= min_code && code <= max_code))
            ^ invert;
}

static bool
icmp_match(const struct sk_buff *skb,
         const struct net_device *in,
         const struct net_device *out,
         const struct xt_match *match,
         const void *matchinfo,
         int offset,
         unsigned int protoff,
         bool *hotdrop)
{
      struct icmphdr _icmph, *ic;
      const struct ipt_icmp *icmpinfo = matchinfo;

      /* Must not be a fragment. */
      if (offset)
            return false;

      ic = skb_header_pointer(skb, protoff, sizeof(_icmph), &_icmph);
      if (ic == NULL) {
            /* We've been asked to examine this packet, and we
             * can't.  Hence, no choice but to drop.
             */
            duprintf("Dropping evil ICMP tinygram.\n");
            *hotdrop = true;
            return false;
      }

      return icmp_type_code_match(icmpinfo->type,
                            icmpinfo->code[0],
                            icmpinfo->code[1],
                            ic->type, ic->code,
                            !!(icmpinfo->invflags&IPT_ICMP_INV));
}

/* Called when user tries to insert an entry of this type. */
static bool
icmp_checkentry(const char *tablename,
         const void *info,
         const struct xt_match *match,
         void *matchinfo,
         unsigned int hook_mask)
{
      const struct ipt_icmp *icmpinfo = matchinfo;

      /* Must specify no unknown invflags */
      return !(icmpinfo->invflags & ~IPT_ICMP_INV);
}

/* The built-in targets: standard (NULL) and error. */
static struct xt_target ipt_standard_target __read_mostly = {
      .name       = IPT_STANDARD_TARGET,
      .targetsize = sizeof(int),
      .family           = AF_INET,
#ifdef CONFIG_COMPAT
      .compatsize = sizeof(compat_int_t),
      .compat_from_user = compat_standard_from_user,
      .compat_to_user   = compat_standard_to_user,
#endif
};

static struct xt_target ipt_error_target __read_mostly = {
      .name       = IPT_ERROR_TARGET,
      .target           = ipt_error,
      .targetsize = IPT_FUNCTION_MAXNAMELEN,
      .family           = AF_INET,
};

static struct nf_sockopt_ops ipt_sockopts = {
      .pf         = PF_INET,
      .set_optmin = IPT_BASE_CTL,
      .set_optmax = IPT_SO_SET_MAX+1,
      .set        = do_ipt_set_ctl,
#ifdef CONFIG_COMPAT
      .compat_set = compat_do_ipt_set_ctl,
#endif
      .get_optmin = IPT_BASE_CTL,
      .get_optmax = IPT_SO_GET_MAX+1,
      .get        = do_ipt_get_ctl,
#ifdef CONFIG_COMPAT
      .compat_get = compat_do_ipt_get_ctl,
#endif
      .owner            = THIS_MODULE,
};

static struct xt_match icmp_matchstruct __read_mostly = {
      .name       = "icmp",
      .match            = icmp_match,
      .matchsize  = sizeof(struct ipt_icmp),
      .proto            = IPPROTO_ICMP,
      .family           = AF_INET,
      .checkentry = icmp_checkentry,
};

static int __init ip_tables_init(void)
{
      int ret;

      ret = xt_proto_init(AF_INET);
      if (ret < 0)
            goto err1;

      /* Noone else will be downing sem now, so we won't sleep */
      ret = xt_register_target(&ipt_standard_target);
      if (ret < 0)
            goto err2;
      ret = xt_register_target(&ipt_error_target);
      if (ret < 0)
            goto err3;
      ret = xt_register_match(&icmp_matchstruct);
      if (ret < 0)
            goto err4;

      /* Register setsockopt */
      ret = nf_register_sockopt(&ipt_sockopts);
      if (ret < 0)
            goto err5;

      printk(KERN_INFO "ip_tables: (C) 2000-2006 Netfilter Core Team\n");
      return 0;

err5:
      xt_unregister_match(&icmp_matchstruct);
err4:
      xt_unregister_target(&ipt_error_target);
err3:
      xt_unregister_target(&ipt_standard_target);
err2:
      xt_proto_fini(AF_INET);
err1:
      return ret;
}

static void __exit ip_tables_fini(void)
{
      nf_unregister_sockopt(&ipt_sockopts);

      xt_unregister_match(&icmp_matchstruct);
      xt_unregister_target(&ipt_error_target);
      xt_unregister_target(&ipt_standard_target);

      xt_proto_fini(AF_INET);
}

EXPORT_SYMBOL(ipt_register_table);
EXPORT_SYMBOL(ipt_unregister_table);
EXPORT_SYMBOL(ipt_do_table);
module_init(ip_tables_init);
module_exit(ip_tables_fini);

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