text: /*
   * 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.
   */
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  #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>
  #include <net/netfilter/nf_log.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",		\
  		       __func__, __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. */
  /* Performance critical - called for every packet */
  static inline bool
  ip_packet_match(const struct iphdr *ip,
  		const char *indev,
  		const char *outdev,
  		const struct ipt_ip *ipinfo,
  		int isfrag)
  {
  	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: %pI4. Mask: %pI4. Target: %pI4.%s\n",
  			&ip->saddr, &ipinfo->smsk.s_addr, &ipinfo->src.s_addr,
  			ipinfo->invflags & IPT_INV_SRCIP ? " (INV)" : "");
  		dprintf("DST: %pI4 Mask: %pI4 Target: %pI4.%s\n",
  			&ip->daddr, &ipinfo->dmsk.s_addr, &ipinfo->dst.s_addr,
  			ipinfo->invflags & IPT_INV_DSTIP ? " (INV)" : "");
  		return false;
  	}
  
  	ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask);
  
  	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 false;
  	}
  
  	ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask);
  
  	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 false;
  	}
  
  	/* 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 false;
  	}
  
  	/* 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 false;
  	}
  
  	return true;
  }
  
  static 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 xt_target_param *par)
  {
  	if (net_ratelimit())
  		printk("ip_tables: error: `%s'\n",
  		       (const char *)par->targinfo);
  
  	return NF_DROP;
  }
  
  /* Performance critical - called for every packet */
  static inline bool
  do_match(struct ipt_entry_match *m, const struct sk_buff *skb,
  	 struct xt_match_param *par)
  {
  	par->match     = m->u.kernel.match;
  	par->matchinfo = m->data;
  
  	/* Stop iteration if it doesn't match */
  	if (!m->u.kernel.match->match(skb, par))
  		return true;
  	else
  		return false;
  }
  
  /* Performance critical */
  static inline struct ipt_entry *
  get_entry(void *base, unsigned int offset)
  {
  	return (struct ipt_entry *)(base + offset);
  }
  
  /* All zeroes == unconditional rule. */
  /* Mildly perf critical (only if packet tracing is on) */
  static inline bool unconditional(const struct ipt_ip *ip)
  {
  	static const struct ipt_ip uncond;
  
  	return memcmp(ip, &uncond, sizeof(uncond)) == 0;
  #undef FWINV
  }
  
  #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \
      defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE)
  static const char *const hooknames[] = {
  	[NF_INET_PRE_ROUTING]		= "PREROUTING",
  	[NF_INET_LOCAL_IN]		= "INPUT",
  	[NF_INET_FORWARD]		= "FORWARD",
  	[NF_INET_LOCAL_OUT]		= "OUTPUT",
  	[NF_INET_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 *const 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,
  		},
  	},
  };
  
  /* Mildly perf critical (only if packet tracing is on) */
  static inline int
  get_chainname_rulenum(struct ipt_entry *s, struct ipt_entry *e,
  		      const char *hookname, const char **chainname,
  		      const 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
  				? comments[NF_IP_TRACE_COMMENT_POLICY]
  				: 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,
  			 const char *tablename,
  			 struct xt_table_info *private,
  			 struct ipt_entry *e)
  {
  	void *table_base;
  	const struct ipt_entry *root;
  	const char *hookname, *chainname, *comment;
  	unsigned int rulenum = 0;
  
  	table_base = private->entries[smp_processor_id()];
  	root = get_entry(table_base, private->hook_entry[hook]);
  
  	hookname = chainname = hooknames[hook];
  	comment = 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
  
  static inline __pure
  struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
  {
  	return (void *)entry + entry->next_offset;
  }
  
  /* 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)
  {
  #define tb_comefrom ((struct ipt_entry *)table_base)->comefrom
  
  	static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
  	const struct iphdr *ip;
  	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;
  	struct xt_match_param mtpar;
  	struct xt_target_param tgpar;
  
  	/* Initialization */
  	ip = ip_hdr(skb);
  	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. */
  	mtpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
  	mtpar.thoff   = ip_hdrlen(skb);
  	mtpar.hotdrop = &hotdrop;
  	mtpar.in      = tgpar.in  = in;
  	mtpar.out     = tgpar.out = out;
  	mtpar.family  = tgpar.family = NFPROTO_IPV4;
  	mtpar.hooknum = tgpar.hooknum = hook;
  
  	IP_NF_ASSERT(table->valid_hooks & (1 << hook));
  	xt_info_rdlock_bh();
  	private = table->private;
  	table_base = 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 {
  		struct ipt_entry_target *t;
  
  		IP_NF_ASSERT(e);
  		IP_NF_ASSERT(back);
  		if (!ip_packet_match(ip, indev, outdev,
  		    &e->ip, mtpar.fragoff) ||
  		    IPT_MATCH_ITERATE(e, do_match, skb, &mtpar) != 0) {
  			e = ipt_next_entry(e);
  			continue;
  		}
  
  		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 != ipt_next_entry(e)
  			    && !(e->ip.flags & IPT_F_GOTO)) {
  				/* Save old back ptr in next entry */
  				struct ipt_entry *next = ipt_next_entry(e);
  				next->comefrom = (void *)back - table_base;
  				/* set back pointer to next entry */
  				back = next;
  			}
  
  			e = get_entry(table_base, v);
  			continue;
  		}
  
  		/* Targets which reenter must return
  		   abs. verdicts */
  		tgpar.target   = t->u.kernel.target;
  		tgpar.targinfo = t->data;
  
  
  #ifdef CONFIG_NETFILTER_DEBUG
  		tb_comefrom = 0xeeeeeeec;
  #endif
  		verdict = t->u.kernel.target->target(skb, &tgpar);
  #ifdef CONFIG_NETFILTER_DEBUG
  		if (tb_comefrom != 0xeeeeeeec && verdict == IPT_CONTINUE) {
  			printk("Target %s reentered!\n",
  			       t->u.kernel.target->name);
  			verdict = NF_DROP;
  		}
  		tb_comefrom = 0x57acc001;
  #endif
  		/* Target might have changed stuff. */
  		ip = ip_hdr(skb);
  		if (verdict == IPT_CONTINUE)
  			e = ipt_next_entry(e);
  		else
  			/* Verdict */
  			break;
  	} while (!hotdrop);
  	xt_info_rdunlock_bh();
  
  #ifdef DEBUG_ALLOW_ALL
  	return NF_ACCEPT;
  #else
  	if (hotdrop)
  		return NF_DROP;
  	else return verdict;
  #endif
  
  #undef tb_comefrom
  }
  
  /* 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_INET_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_INET_NUMHOOKS)) {
  				printk("iptables: loop hook %u pos %u %08X.\n",
  				       hook, pos, e->comefrom);
  				return 0;
  			}
  			e->comefrom |= ((1 << hook) | (1 << NF_INET_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 ((strcmp(t->target.u.user.name,
  			    		    IPT_STANDARD_TARGET) == 0) &&
  				    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_INET_NUMHOOKS);
  #ifdef DEBUG_IP_FIREWALL_USER
  					if (e->comefrom
  					    & (1 << NF_INET_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 int
  cleanup_match(struct ipt_entry_match *m, unsigned int *i)
  {
  	struct xt_mtdtor_param par;
  
  	if (i && (*i)-- == 0)
  		return 1;
  
  	par.match     = m->u.kernel.match;
  	par.matchinfo = m->data;
  	par.family    = NFPROTO_IPV4;
  	if (par.match->destroy != NULL)
  		par.match->destroy(&par);
  	module_put(par.match->me);
  	return 0;
  }
  
  static 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 int
  check_match(struct ipt_entry_match *m, struct xt_mtchk_param *par,
  	    unsigned int *i)
  {
  	const struct ipt_ip *ip = par->entryinfo;
  	int ret;
  
  	par->match     = m->u.kernel.match;
  	par->matchinfo = m->data;
  
  	ret = xt_check_match(par, m->u.match_size - sizeof(*m),
  	      ip->proto, ip->invflags & IPT_INV_PROTO);
  	if (ret < 0) {
  		duprintf("ip_tables: check failed for `%s'.\n",
  			 par.match->name);
  		return ret;
  	}
  	++*i;
  	return 0;
  }
  
  static int
  find_check_match(struct ipt_entry_match *m, struct xt_mtchk_param *par,
  		 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, par, i);
  	if (ret)
  		goto err;
  
  	return 0;
  err:
  	module_put(m->u.kernel.match->me);
  	return ret;
  }
  
  static int check_target(struct ipt_entry *e, const char *name)
  {
  	struct ipt_entry_target *t = ipt_get_target(e);
  	struct xt_tgchk_param par = {
  		.table     = name,
  		.entryinfo = e,
  		.target    = t->u.kernel.target,
  		.targinfo  = t->data,
  		.hook_mask = e->comefrom,
  		.family    = NFPROTO_IPV4,
  	};
  	int ret;
  
  	ret = xt_check_target(&par, t->u.target_size - sizeof(*t),
  	      e->ip.proto, e->ip.invflags & IPT_INV_PROTO);
  	if (ret < 0) {
  		duprintf("ip_tables: check failed for `%s'.\n",
  			 t->u.kernel.target->name);
  		return ret;
  	}
  	return 0;
  }
  
  static 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;
  	struct xt_mtchk_param mtpar;
  
  	ret = check_entry(e, name);
  	if (ret)
  		return ret;
  
  	j = 0;
  	mtpar.table     = name;
  	mtpar.entryinfo = &e->ip;
  	mtpar.hook_mask = e->comefrom;
  	mtpar.family    = NFPROTO_IPV4;
  	ret = IPT_MATCH_ITERATE(e, find_check_match, &mtpar, &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 bool check_underflow(struct ipt_entry *e)
  {
  	const struct ipt_entry_target *t;
  	unsigned int verdict;
  
  	if (!unconditional(&e->ip))
  		return false;
  	t = ipt_get_target(e);
  	if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
  		return false;
  	verdict = ((struct ipt_standard_target *)t)->verdict;
  	verdict = -verdict - 1;
  	return verdict == NF_DROP || verdict == NF_ACCEPT;
  }
  
  static 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 valid_hooks,
  			   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_INET_NUMHOOKS; h++) {
  		if (!(valid_hooks & (1 << h)))
  			continue;
  		if ((unsigned char *)e - base == hook_entries[h])
  			newinfo->hook_entry[h] = hook_entries[h];
  		if ((unsigned char *)e - base == underflows[h]) {
  			if (!check_underflow(e)) {
  				pr_err("Underflows must be unconditional and "
  				       "use the STANDARD target with "
  				       "ACCEPT/DROP\n");
  				return -EINVAL;
  			}
  			newinfo->underflow[h] = underflows[h];
  		}
  	}
  
  	/* Clear counters and comefrom */
  	e->counters = ((struct xt_counters) { 0, 0 });
  	e->comefrom = 0;
  
  	(*i)++;
  	return 0;
  }
  
  static int
  cleanup_entry(struct ipt_entry *e, unsigned int *i)
  {
  	struct xt_tgdtor_param par;
  	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);
  
  	par.target   = t->u.kernel.target;
  	par.targinfo = t->data;
  	par.family   = NFPROTO_IPV4;
  	if (par.target->destroy != NULL)
  		par.target->destroy(&par);
  	module_put(par.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_INET_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, valid_hooks, &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_INET_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.
  	 *
  	 * Bottom half has to be disabled to prevent deadlock
  	 * if new softirq were to run and call ipt_do_table
  	 */
  	local_bh_disable();
  	curcpu = 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;
  		xt_info_wrlock(cpu);
  		IPT_ENTRY_ITERATE(t->entries[cpu],
  				  t->size,
  				  add_entry_to_counter,
  				  counters,
  				  &i);
  		xt_info_wrunlock(cpu);
  	}
  	local_bh_enable();
  }
  
  static 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);
  
  	get_counters(private, counters);
  
  	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;
  	const struct xt_table_info *private = table->private;
  	int ret = 0;
  	const 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()];
  	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;
  		const struct ipt_entry_match *m;
  		const 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
  static void compat_standard_from_user(void *dst, void *src)
  {
  	int v = *(compat_int_t *)src;
  
  	if (v > 0)
  		v += xt_compat_calc_jump(AF_INET, 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 -= xt_compat_calc_jump(AF_INET, 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,
  			     const 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 = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
  	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 = xt_compat_add_offset(AF_INET, entry_offset, off);
  	if (ret)
  		return ret;
  
  	for (i = 0; i < NF_INET_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(const struct xt_table_info *info,
  			     struct xt_table_info *newinfo)
  {
  	void *loc_cpu_entry;
  
  	if (!newinfo || !info)
  		return -EINVAL;
  
  	/* we dont care about newinfo->entries[] */
  	memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
  	newinfo->initial_entries = 0;
  	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(struct net *net, 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 != %zu\n", *len,
  			 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(net, AF_INET, name),
  				    "iptable_%s", name);
  	if (t && !IS_ERR(t)) {
  		struct ipt_getinfo info;
  		const struct xt_table_info *private = t->private;
  #ifdef CONFIG_COMPAT
  		struct xt_table_info tmp;
  
  		if (compat) {
  			ret = compat_table_info(private, &tmp);
  			xt_compat_flush_offsets(AF_INET);
  			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 net *net, 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 < %zu\n", *len, 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 != %zu\n",
  			 *len, sizeof(get) + get.size);
  		return -EINVAL;
  	}
  
  	t = xt_find_table_lock(net, AF_INET, get.name);
  	if (t && !IS_ERR(t)) {
  		const 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 = -EAGAIN;
  		}
  		module_put(t->me);
  		xt_table_unlock(t);
  	} else
  		ret = t ? PTR_ERR(t) : -ENOENT;
  
  	return ret;
  }
  
  static int
  __do_replace(struct net *net, 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(net, 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, and synchronize with replace */
  	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(struct net *net, 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;
  
  	/* overflow check */
  	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
  		return -ENOMEM;
  	tmp.name[sizeof(tmp.name)-1] = 0;
  
  	newinfo = xt_alloc_table_info(tmp.size);
  	if (!newinfo)
  		return -ENOMEM;
  
  	/* choose the copy that is on 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(net, 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 int
  add_counter_to_entry(struct ipt_entry *e,
  		     const struct xt_counters addme[],
  		     unsigned int *i)
  {
  	ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);
  
  	(*i)++;
  	return 0;
  }
  
  static int
  do_add_counters(struct net *net, void __user *user, unsigned int len, int compat)
  {
  	unsigned int i, curcpu;
  	struct xt_counters_info tmp;
  	struct xt_counters *paddc;
  	unsigned int num_counters;
  	const char *name;
  	int size;
  	void *ptmp;
  	struct xt_table *t;
  	const 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(net, AF_INET, name);
  	if (!t || IS_ERR(t)) {
  		ret = t ? PTR_ERR(t) : -ENOENT;
  		goto free;
  	}
  
  	local_bh_disable();
  	private = t->private;
  	if (private->number != num_counters) {
  		ret = -EINVAL;
  		goto unlock_up_free;
  	}
  
  	i = 0;
  	/* Choose the copy that is on our node */
  	curcpu = smp_processor_id();
  	loc_cpu_entry = private->entries[curcpu];
  	xt_info_wrlock(curcpu);
  	IPT_ENTRY_ITERATE(loc_cpu_entry,
  			  private->size,
  			  add_counter_to_entry,
  			  paddc,
  			  &i);
  	xt_info_wrunlock(curcpu);
   unlock_up_free:
  	local_bh_enable();
  	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_INET_NUMHOOKS];
  	u32			underflow[NF_INET_NUMHOOKS];
  	u32			num_counters;
  	compat_uptr_t		counters;	/* struct ipt_counters * */
  	struct compat_ipt_entry	entries[0];
  };
  
  static int
  compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
  			  unsigned int *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);
  	*size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
  
  	ret = IPT_MATCH_ITERATE(e, xt_compat_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 int
  compat_find_calc_match(struct ipt_entry_match *m,
  		       const char *name,
  		       const struct ipt_ip *ip,
  		       unsigned int hookmask,
  		       int *size, unsigned 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 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 int
  compat_release_entry(struct compat_ipt_entry *e, unsigned int *i)
  {
  	struct ipt_entry_target *t;
  
  	if (i && (*i)-- == 0)
  		return 1;
  
  	/* Cleanup all matches */
  	COMPAT_IPT_MATCH_ITERATE(e, compat_release_match, NULL);
  	t = compat_ipt_get_target(e);
  	module_put(t->u.kernel.target->me);
  	return 0;
  }
  
  static int
  check_compat_entry_size_and_hooks(struct compat_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;
  	unsigned int j;
  	int ret, off, h;
  
  	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;
  	}
  
  	/* For purposes of check_entry casting the compat entry is fine */
  	ret = check_entry((struct ipt_entry *)e, name);
  	if (ret)
  		return ret;
  
  	off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
  	entry_offset = (void *)e - (void *)base;
  	j = 0;
  	ret = COMPAT_IPT_MATCH_ITERATE(e, compat_find_calc_match, name,
  				       &e->ip, e->comefrom, &off, &j);
  	if (ret != 0)
  		goto release_matches;
  
  	t = compat_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 = xt_compat_add_offset(AF_INET, entry_offset, off);
  	if (ret)
  		goto out;
  
  	/* Check hooks & underflows */
  	for (h = 0; h < NF_INET_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 */
  	memset(&e->counters, 0, sizeof(e->counters));
  	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 int
  compat_copy_entry_from_user(struct compat_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));
  	memcpy(&de->counters, &e->counters, sizeof(e->counters));
  
  	*dstptr += sizeof(struct ipt_entry);
  	*size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
  
  	ret = COMPAT_IPT_MATCH_ITERATE(e, xt_compat_match_from_user,
  				       dstptr, size);
  	if (ret)
  		return ret;
  	de->target_offset = e->target_offset - (origsize - *size);
  	t = compat_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_INET_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 int
  compat_check_entry(struct ipt_entry *e, const char *name,
  				     unsigned int *i)
  {
  	struct xt_mtchk_param mtpar;
  	unsigned int j;
  	int ret;
  
  	j = 0;
  	mtpar.table     = name;
  	mtpar.entryinfo = &e->ip;
  	mtpar.hook_mask = e->comefrom;
  	mtpar.family    = NFPROTO_IPV4;
  	ret = IPT_MATCH_ITERATE(e, check_match, &mtpar, &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_INET_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 = COMPAT_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_INET_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_INET_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 = COMPAT_IPT_ENTRY_ITERATE(entry0, total_size,
  				       compat_copy_entry_from_user,
  				       &pos, &size, name, newinfo, entry1);
  	xt_compat_flush_offsets(AF_INET);
  	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;
  		COMPAT_IPT_ENTRY_ITERATE_CONTINUE(entry0, 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:
  	COMPAT_IPT_ENTRY_ITERATE(entry0, total_size, compat_release_entry, &j);
  	return ret;
  out_unlock:
  	xt_compat_flush_offsets(AF_INET);
  	xt_compat_unlock(AF_INET);
  	goto out;
  }
  
  static int
  compat_do_replace(struct net *net, 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;
  
  	/* overflow check */
  	if (tmp.size >= INT_MAX / num_possible_cpus())
  		return -ENOMEM;
  	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
  		return -ENOMEM;
  	tmp.name[sizeof(tmp.name)-1] = 0;
  
  	newinfo = xt_alloc_table_info(tmp.size);
  	if (!newinfo)
  		return -ENOMEM;
  
  	/* choose the copy that is on 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(net, 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(sock_net(sk), user, len);
  		break;
  
  	case IPT_SO_SET_ADD_COUNTERS:
  		ret = do_add_counters(sock_net(sk), 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;
  	const struct xt_table_info *private = table->private;
  	void __user *pos;
  	unsigned int size;
  	int ret = 0;
  	const 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 net *net, 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 < %zu\n", *len, 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 != %zu\n",
  			 *len, sizeof(get) + get.size);
  		return -EINVAL;
  	}
  
  	xt_compat_lock(AF_INET);
  	t = xt_find_table_lock(net, AF_INET, get.name);
  	if (t && !IS_ERR(t)) {
  		const 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 = -EAGAIN;
  		}
  		xt_compat_flush_offsets(AF_INET);
  		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(sock_net(sk), user, len, 1);
  		break;
  	case IPT_SO_GET_ENTRIES:
  		ret = compat_get_entries(sock_net(sk), 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(sock_net(sk), user, len);
  		break;
  
  	case IPT_SO_SET_ADD_COUNTERS:
  		ret = do_add_counters(sock_net(sk), 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(sock_net(sk), user, len, 0);
  		break;
  
  	case IPT_SO_GET_ENTRIES:
  		ret = get_entries(sock_net(sk), 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;
  		}
  		rev.name[sizeof(rev.name)-1] = 0;
  
  		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;
  }
  
  struct xt_table *ipt_register_table(struct net *net,
  				    const struct xt_table *table,
  				    const struct ipt_replace *repl)
  {
  	int ret;
  	struct xt_table_info *newinfo;
  	struct xt_table_info bootstrap
  		= { 0, 0, 0, { 0 }, { 0 }, { } };
  	void *loc_cpu_entry;
  	struct xt_table *new_table;
  
  	newinfo = xt_alloc_table_info(repl->size);
  	if (!newinfo) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	/* choose the copy on our node/cpu, but dont care about 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)
  		goto out_free;
  
  	new_table = xt_register_table(net, table, &bootstrap, newinfo);
  	if (IS_ERR(new_table)) {
  		ret = PTR_ERR(new_table);
  		goto out_free;
  	}
  
  	return new_table;
  
  out_free:
  	xt_free_table_info(newinfo);
  out:
  	return ERR_PTR(ret);
  }
  
  void ipt_unregister_table(struct xt_table *table)
  {
  	struct xt_table_info *private;
  	void *loc_cpu_entry;
  	struct module *table_owner = table->me;
  
  	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);
  	if (private->number > private->initial_entries)
  		module_put(table_owner);
  	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 xt_match_param *par)
  {
  	const struct icmphdr *ic;
  	struct icmphdr _icmph;
  	const struct ipt_icmp *icmpinfo = par->matchinfo;
  
  	/* Must not be a fragment. */
  	if (par->fragoff != 0)
  		return false;
  
  	ic = skb_header_pointer(skb, par->thoff, 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");
  		*par->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));
  }
  
  static bool icmp_checkentry(const struct xt_mtchk_param *par)
  {
  	const struct ipt_icmp *icmpinfo = par->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		= NFPROTO_IPV4,
  #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		= NFPROTO_IPV4,
  };
  
  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),
  	.checkentry	= icmp_checkentry,
  	.proto		= IPPROTO_ICMP,
  	.family		= NFPROTO_IPV4,
  };
  
  static int __net_init ip_tables_net_init(struct net *net)
  {
  	return xt_proto_init(net, NFPROTO_IPV4);
  }
  
  static void __net_exit ip_tables_net_exit(struct net *net)
  {
  	xt_proto_fini(net, NFPROTO_IPV4);
  }
  
  static struct pernet_operations ip_tables_net_ops = {
  	.init = ip_tables_net_init,
  	.exit = ip_tables_net_exit,
  };
  
  static int __init ip_tables_init(void)
  {
  	int ret;
  
  	ret = register_pernet_subsys(&ip_tables_net_ops);
  	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:
  	unregister_pernet_subsys(&ip_tables_net_ops);
  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);
  
  	unregister_pernet_subsys(&ip_tables_net_ops);
  }
  
  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);
  