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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [ipv6/] [netfilter/] [ip6_tables.c] - Blame information for rev 1765

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/*
 * Packet matching code.
 *
 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
 * Copyright (C) 2000-2002 Netfilter core team <coreteam@netfilter.org>
 *
 * 19 Jan 2002 Harald Welte <laforge@gnumonks.org>
 *      - increase module usage count as soon as we have rules inside
 *        a table
 * 06 Jun 2002 Andras Kis-Szabo <kisza@sch.bme.hu>
 *      - new extension header parser code
 */
#include <linux/config.h>
#include <linux/skbuff.h>
#include <linux/kmod.h>
#include <linux/vmalloc.h>
#include <linux/netdevice.h>
#include <linux/module.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmpv6.h>
#include <net/ip.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
#include <linux/proc_fs.h>
 
#include <linux/netfilter_ipv6/ip6_tables.h>
 
#define IPV6_HDR_LEN    (sizeof(struct ipv6hdr))
#define IPV6_OPTHDR_LEN (sizeof(struct ipv6_opt_hdr))
 
/*#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
#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
 
/* Mutex protects lists (only traversed in user context). */
static DECLARE_MUTEX(ip6t_mutex);
 
/* Must have mutex */
#define ASSERT_READ_LOCK(x) IP_NF_ASSERT(down_trylock(&ip6t_mutex) != 0)
#define ASSERT_WRITE_LOCK(x) IP_NF_ASSERT(down_trylock(&ip6t_mutex) != 0)
#include <linux/netfilter_ipv4/lockhelp.h>
#include <linux/netfilter_ipv4/listhelp.h>
 
#if 0
/* All the better to debug you with... */
#define static
#define inline
#endif
 
/* Locking is simple: we assume at worst case there will be one packet
   in user context and one from bottom halves (or soft irq if Alexey's
   softnet patch was applied).
 
   We keep a set of rules for each CPU, so we can avoid write-locking
   them; doing a readlock_bh() stops packets coming through if we're
   in user context.
 
   To be cache friendly on SMP, we arrange them like so:
   [ n-entries ]
   ... cache-align padding ...
   [ n-entries ]
 
   Hence the start of any table is given by get_table() below.  */
 
/* The table itself */
struct ip6t_table_info
{
        /* Size per table */
        unsigned int size;
        /* Number of entries: FIXME. --RR */
        unsigned int number;
        /* Initial number of entries. Needed for module usage count */
        unsigned int initial_entries;
 
        /* Entry points and underflows */
        unsigned int hook_entry[NF_IP6_NUMHOOKS];
        unsigned int underflow[NF_IP6_NUMHOOKS];
 
        /* ip6t_entry tables: one per CPU */
        char entries[0] ____cacheline_aligned;
};
 
static LIST_HEAD(ip6t_target);
static LIST_HEAD(ip6t_match);
static LIST_HEAD(ip6t_tables);
#define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
 
#ifdef CONFIG_SMP
#define TABLE_OFFSET(t,p) (SMP_ALIGN((t)->size)*(p))
#else
#define TABLE_OFFSET(t,p) 0
#endif
 
#if 0
#define down(x) do { printk("DOWN:%u:" #x "\n", __LINE__); down(x); } while(0)
#define down_interruptible(x) ({ int __r; printk("DOWNi:%u:" #x "\n", __LINE__); __r = down_interruptible(x); if (__r != 0) printk("ABORT-DOWNi:%u\n", __LINE__); __r; })
#define up(x) do { printk("UP:%u:" #x "\n", __LINE__); up(x); } while(0)
#endif
 
static int ip6_masked_addrcmp(struct in6_addr addr1, struct in6_addr mask,
                              struct in6_addr addr2)
{
        int i;
        for( i = 0; i < 16; i++){
                if((addr1.s6_addr[i] & mask.s6_addr[i]) !=
                   (addr2.s6_addr[i] & mask.s6_addr[i]))
                        return 1;
        }
        return 0;
}
 
/* Check for an extension */
int
ip6t_ext_hdr(u8 nexthdr)
{
        return ( (nexthdr == IPPROTO_HOPOPTS)   ||
                 (nexthdr == IPPROTO_ROUTING)   ||
                 (nexthdr == IPPROTO_FRAGMENT)  ||
                 (nexthdr == IPPROTO_ESP)       ||
                 (nexthdr == IPPROTO_AH)        ||
                 (nexthdr == IPPROTO_NONE)      ||
                 (nexthdr == IPPROTO_DSTOPTS) );
}
 
/* Returns whether matches rule or not. */
static inline int
ip6_packet_match(const struct sk_buff *skb,
                 const struct ipv6hdr *ipv6,
                 const char *indev,
                 const char *outdev,
                 const struct ip6t_ip6 *ip6info,
                 int isfrag)
{
        size_t i;
        unsigned long ret;
 
#define FWINV(bool,invflg) ((bool) ^ !!(ip6info->invflags & invflg))
 
        if (FWINV(ip6_masked_addrcmp(ipv6->saddr,ip6info->smsk,ip6info->src),
                  IP6T_INV_SRCIP)
            || FWINV(ip6_masked_addrcmp(ipv6->daddr,ip6info->dmsk,ip6info->dst),
                     IP6T_INV_DSTIP)) {
                dprintf("Source or dest mismatch.\n");
/*
                dprintf("SRC: %u. Mask: %u. Target: %u.%s\n", ip->saddr,
                        ipinfo->smsk.s_addr, ipinfo->src.s_addr,
                        ipinfo->invflags & IP6T_INV_SRCIP ? " (INV)" : "");
                dprintf("DST: %u. Mask: %u. Target: %u.%s\n", ip->daddr,
                        ipinfo->dmsk.s_addr, ipinfo->dst.s_addr,
                        ipinfo->invflags & IP6T_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 *)ip6info->iniface)[i])
                        & ((const unsigned long *)ip6info->iniface_mask)[i];
        }
 
        if (FWINV(ret != 0, IP6T_INV_VIA_IN)) {
                dprintf("VIA in mismatch (%s vs %s).%s\n",
                        indev, ip6info->iniface,
                        ip6info->invflags&IP6T_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 *)ip6info->outiface)[i])
                        & ((const unsigned long *)ip6info->outiface_mask)[i];
        }
 
        if (FWINV(ret != 0, IP6T_INV_VIA_OUT)) {
                dprintf("VIA out mismatch (%s vs %s).%s\n",
                        outdev, ip6info->outiface,
                        ip6info->invflags&IP6T_INV_VIA_OUT ?" (INV)":"");
                return 0;
        }
 
/* ... might want to do something with class and flowlabel here ... */
 
        /* look for the desired protocol header */
        if((ip6info->flags & IP6T_F_PROTO)) {
                u_int8_t currenthdr = ipv6->nexthdr;
                struct ipv6_opt_hdr *hdrptr;
                u_int16_t ptr;          /* Header offset in skb */
                u_int16_t hdrlen;       /* Header */
 
                ptr = IPV6_HDR_LEN;
 
                while (ip6t_ext_hdr(currenthdr)) {
                        /* Is there enough space for the next ext header? */
                        if (skb->len - ptr < IPV6_OPTHDR_LEN)
                                return 0;
 
                        /* NONE or ESP: there isn't protocol part */
                        /* If we want to count these packets in '-p all',
                         * we will change the return 0 to 1*/
                        if ((currenthdr == IPPROTO_NONE) ||
                                (currenthdr == IPPROTO_ESP))
                                return 0;
 
                        hdrptr = (struct ipv6_opt_hdr *)(skb->data + ptr);
 
                        /* Size calculation */
                        if (currenthdr == IPPROTO_FRAGMENT) {
                                hdrlen = 8;
                        } else if (currenthdr == IPPROTO_AH)
                                hdrlen = (hdrptr->hdrlen+2)<<2;
                        else
                                hdrlen = ipv6_optlen(hdrptr);
 
                        currenthdr = hdrptr->nexthdr;
                        ptr += hdrlen;
                        /* ptr is too large */
                        if ( ptr > skb->len )
                                return 0;
                }
 
                /* currenthdr contains the protocol header */
 
                dprintf("Packet protocol %hi ?= %s%hi.\n",
                                currenthdr,
                                ip6info->invflags & IP6T_INV_PROTO ? "!":"",
                                ip6info->proto);
 
                if (ip6info->proto == currenthdr) {
                        if(ip6info->invflags & IP6T_INV_PROTO) {
                                return 0;
                        }
                        return 1;
                }
 
                /* We need match for the '-p all', too! */
                if ((ip6info->proto != 0) &&
                        !(ip6info->invflags & IP6T_INV_PROTO))
                        return 0;
        }
        return 1;
}
 
/* should be ip6 safe */
static inline int
ip6_checkentry(const struct ip6t_ip6 *ipv6)
{
        if (ipv6->flags & ~IP6T_F_MASK) {
                duprintf("Unknown flag bits set: %08X\n",
                         ipv6->flags & ~IP6T_F_MASK);
                return 0;
        }
        if (ipv6->invflags & ~IP6T_INV_MASK) {
                duprintf("Unknown invflag bits set: %08X\n",
                         ipv6->invflags & ~IP6T_INV_MASK);
                return 0;
        }
        return 1;
}
 
static unsigned int
ip6t_error(struct sk_buff **pskb,
          unsigned int hooknum,
          const struct net_device *in,
          const struct net_device *out,
          const void *targinfo,
          void *userinfo)
{
        if (net_ratelimit())
                printk("ip6_tables: error: `%s'\n", (char *)targinfo);
 
        return NF_DROP;
}
 
static inline
int do_match(struct ip6t_entry_match *m,
             const struct sk_buff *skb,
             const struct net_device *in,
             const struct net_device *out,
             int offset,
             const void *hdr,
             u_int16_t datalen,
             int *hotdrop)
{
        /* Stop iteration if it doesn't match */
        if (!m->u.kernel.match->match(skb, in, out, m->data,
                                      offset, hdr, datalen, hotdrop))
                return 1;
        else
                return 0;
}
 
static inline struct ip6t_entry *
get_entry(void *base, unsigned int offset)
{
        return (struct ip6t_entry *)(base + offset);
}
 
/* Returns one of the generic firewall policies, like NF_ACCEPT. */
unsigned int
ip6t_do_table(struct sk_buff **pskb,
              unsigned int hook,
              const struct net_device *in,
              const struct net_device *out,
              struct ip6t_table *table,
              void *userdata)
{
        static const char nulldevname[IFNAMSIZ] = { 0 };
        u_int16_t offset = 0;
        struct ipv6hdr *ipv6;
        void *protohdr;
        u_int16_t datalen;
        int hotdrop = 0;
        /* Initializing verdict to NF_DROP keeps gcc happy. */
        unsigned int verdict = NF_DROP;
        const char *indev, *outdev;
        void *table_base;
        struct ip6t_entry *e, *back;
 
        /* Initialization */
        ipv6 = (*pskb)->nh.ipv6h;
        protohdr = (u_int32_t *)((char *)ipv6 + IPV6_HDR_LEN);
        datalen = (*pskb)->len - IPV6_HDR_LEN;
        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. */
 
        read_lock_bh(&table->lock);
        IP_NF_ASSERT(table->valid_hooks & (1 << hook));
        table_base = (void *)table->private->entries
                + TABLE_OFFSET(table->private,
                                cpu_number_map(smp_processor_id()));
        e = get_entry(table_base, table->private->hook_entry[hook]);
 
#ifdef CONFIG_NETFILTER_DEBUG
        /* Check noone else using our table */
        if (((struct ip6t_entry *)table_base)->comefrom != 0xdead57ac
            && ((struct ip6t_entry *)table_base)->comefrom != 0xeeeeeeec) {
                printk("ASSERT: CPU #%u, %s comefrom(%p) = %X\n",
                       smp_processor_id(),
                       table->name,
                       &((struct ip6t_entry *)table_base)->comefrom,
                       ((struct ip6t_entry *)table_base)->comefrom);
        }
        ((struct ip6t_entry *)table_base)->comefrom = 0x57acc001;
#endif
 
        /* For return from builtin chain */
        back = get_entry(table_base, table->private->underflow[hook]);
 
        do {
                IP_NF_ASSERT(e);
                IP_NF_ASSERT(back);
                (*pskb)->nfcache |= e->nfcache;
                if (ip6_packet_match(*pskb, ipv6, indev, outdev,
                        &e->ipv6, offset)) {
                        struct ip6t_entry_target *t;
 
                        if (IP6T_MATCH_ITERATE(e, do_match,
                                               *pskb, in, out,
                                               offset, protohdr,
                                               datalen, &hotdrop) != 0)
                                goto no_match;
 
                        ADD_COUNTER(e->counters, ntohs(ipv6->payload_len) + IPV6_HDR_LEN, 1);
 
                        t = ip6t_get_target(e);
                        IP_NF_ASSERT(t->u.kernel.target);
                        /* Standard target? */
                        if (!t->u.kernel.target->target) {
                                int v;
 
                                v = ((struct ip6t_standard_target *)t)->verdict;
                                if (v < 0) {
                                        /* Pop from stack? */
                                        if (v != IP6T_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) {
                                        /* Save old back ptr in next entry */
                                        struct ip6t_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 ip6t_entry *)table_base)->comefrom
                                        = 0xeeeeeeec;
#endif
                                verdict = t->u.kernel.target->target(pskb,
                                                                     hook,
                                                                     in, out,
                                                                     t->data,
                                                                     userdata);
 
#ifdef CONFIG_NETFILTER_DEBUG
                                if (((struct ip6t_entry *)table_base)->comefrom
                                    != 0xeeeeeeec
                                    && verdict == IP6T_CONTINUE) {
                                        printk("Target %s reentered!\n",
                                               t->u.kernel.target->name);
                                        verdict = NF_DROP;
                                }
                                ((struct ip6t_entry *)table_base)->comefrom
                                        = 0x57acc001;
#endif
                                /* Target might have changed stuff. */
                                ipv6 = (*pskb)->nh.ipv6h;
                                protohdr = (u_int32_t *)((void *)ipv6 + IPV6_HDR_LEN);
                                datalen = (*pskb)->len - IPV6_HDR_LEN;
 
                                if (verdict == IP6T_CONTINUE)
                                        e = (void *)e + e->next_offset;
                                else
                                        /* Verdict */
                                        break;
                        }
                } else {
 
                no_match:
                        e = (void *)e + e->next_offset;
                }
        } while (!hotdrop);
 
#ifdef CONFIG_NETFILTER_DEBUG
        ((struct ip6t_entry *)table_base)->comefrom = 0xdead57ac;
#endif
        read_unlock_bh(&table->lock);
 
#ifdef DEBUG_ALLOW_ALL
        return NF_ACCEPT;
#else
        if (hotdrop)
                return NF_DROP;
        else return verdict;
#endif
}
 
/* If it succeeds, returns element and locks mutex */
static inline void *
find_inlist_lock_noload(struct list_head *head,
                        const char *name,
                        int *error,
                        struct semaphore *mutex)
{
        void *ret;
 
#if 1
        duprintf("find_inlist: searching for `%s' in %s.\n",
                 name, head == &ip6t_target ? "ip6t_target"
                 : head == &ip6t_match ? "ip6t_match"
                 : head == &ip6t_tables ? "ip6t_tables" : "UNKNOWN");
#endif
 
        *error = down_interruptible(mutex);
        if (*error != 0)
                return NULL;
 
        ret = list_named_find(head, name);
        if (!ret) {
                *error = -ENOENT;
                up(mutex);
        }
        return ret;
}
 
#ifndef CONFIG_KMOD
#define find_inlist_lock(h,n,p,e,m) find_inlist_lock_noload((h),(n),(e),(m))
#else
static void *
find_inlist_lock(struct list_head *head,
                 const char *name,
                 const char *prefix,
                 int *error,
                 struct semaphore *mutex)
{
        void *ret;
 
        ret = find_inlist_lock_noload(head, name, error, mutex);
        if (!ret) {
                char modulename[IP6T_FUNCTION_MAXNAMELEN + strlen(prefix) + 1];
                strcpy(modulename, prefix);
                strcat(modulename, name);
                duprintf("find_inlist: loading `%s'.\n", modulename);
                request_module(modulename);
                ret = find_inlist_lock_noload(head, name, error, mutex);
        }
 
        return ret;
}
#endif
 
static inline struct ip6t_table *
find_table_lock(const char *name, int *error, struct semaphore *mutex)
{
        return find_inlist_lock(&ip6t_tables, name, "ip6table_", error, mutex);
}
 
static inline struct ip6t_match *
find_match_lock(const char *name, int *error, struct semaphore *mutex)
{
        return find_inlist_lock(&ip6t_match, name, "ip6t_", error, mutex);
}
 
static inline struct ip6t_target *
find_target_lock(const char *name, int *error, struct semaphore *mutex)
{
        return find_inlist_lock(&ip6t_target, name, "ip6t_", error, mutex);
}
 
/* All zeroes == unconditional rule. */
static inline int
unconditional(const struct ip6t_ip6 *ipv6)
{
        unsigned int i;
 
        for (i = 0; i < sizeof(*ipv6); i++)
                if (((char *)ipv6)[i])
                        break;
 
        return (i == sizeof(*ipv6));
}
 
/* 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 ip6t_table_info *newinfo, unsigned int valid_hooks)
{
        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_IP6_NUMHOOKS; hook++) {
                unsigned int pos = newinfo->hook_entry[hook];
                struct ip6t_entry *e
                        = (struct ip6t_entry *)(newinfo->entries + pos);
 
                if (!(valid_hooks & (1 << hook)))
                        continue;
 
                /* Set initial back pointer. */
                e->counters.pcnt = pos;
 
                for (;;) {
                        struct ip6t_standard_target *t
                                = (void *)ip6t_get_target(e);
 
                        if (e->comefrom & (1 << NF_IP6_NUMHOOKS)) {
                                printk("iptables: loop hook %u pos %u %08X.\n",
                                       hook, pos, e->comefrom);
                                return 0;
                        }
                        e->comefrom
                                |= ((1 << hook) | (1 << NF_IP6_NUMHOOKS));
 
                        /* Unconditional return/END. */
                        if (e->target_offset == sizeof(struct ip6t_entry)
                            && (strcmp(t->target.u.user.name,
                                       IP6T_STANDARD_TARGET) == 0)
                            && t->verdict < 0
                            && unconditional(&e->ipv6)) {
                                unsigned int oldpos, size;
 
                                /* Return: backtrack through the last
                                   big jump. */
                                do {
                                        e->comefrom ^= (1<<NF_IP6_NUMHOOKS);
#ifdef DEBUG_IP_FIREWALL_USER
                                        if (e->comefrom
                                            & (1 << NF_IP6_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 ip6t_entry *)
                                                (newinfo->entries + pos);
                                } while (oldpos == pos + e->next_offset);
 
                                /* Move along one */
                                size = e->next_offset;
                                e = (struct ip6t_entry *)
                                        (newinfo->entries + pos + size);
                                e->counters.pcnt = pos;
                                pos += size;
                        } else {
                                int newpos = t->verdict;
 
                                if (strcmp(t->target.u.user.name,
                                           IP6T_STANDARD_TARGET) == 0
                                    && newpos >= 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 ip6t_entry *)
                                        (newinfo->entries + newpos);
                                e->counters.pcnt = pos;
                                pos = newpos;
                        }
                }
                next:
                duprintf("Finished chain %u\n", hook);
        }
        return 1;
}
 
static inline int
cleanup_match(struct ip6t_entry_match *m, unsigned int *i)
{
        if (i && (*i)-- == 0)
                return 1;
 
        if (m->u.kernel.match->destroy)
                m->u.kernel.match->destroy(m->data,
                                           m->u.match_size - sizeof(*m));
 
        if (m->u.kernel.match->me)
                __MOD_DEC_USE_COUNT(m->u.kernel.match->me);
 
        return 0;
}
 
static inline int
standard_check(const struct ip6t_entry_target *t,
               unsigned int max_offset)
{
        struct ip6t_standard_target *targ = (void *)t;
 
        /* Check standard info. */
        if (t->u.target_size
            != IP6T_ALIGN(sizeof(struct ip6t_standard_target))) {
                duprintf("standard_check: target size %u != %u\n",
                         t->u.target_size,
                         IP6T_ALIGN(sizeof(struct ip6t_standard_target)));
                return 0;
        }
 
        if (targ->verdict >= 0
            && targ->verdict > max_offset - sizeof(struct ip6t_entry)) {
                duprintf("ip6t_standard_check: bad verdict (%i)\n",
                         targ->verdict);
                return 0;
        }
 
        if (targ->verdict < -NF_MAX_VERDICT - 1) {
                duprintf("ip6t_standard_check: bad negative verdict (%i)\n",
                         targ->verdict);
                return 0;
        }
        return 1;
}
 
static inline int
check_match(struct ip6t_entry_match *m,
            const char *name,
            const struct ip6t_ip6 *ipv6,
            unsigned int hookmask,
            unsigned int *i)
{
        int ret;
        struct ip6t_match *match;
 
        match = find_match_lock(m->u.user.name, &ret, &ip6t_mutex);
        if (!match) {
          //            duprintf("check_match: `%s' not found\n", m->u.name);
                return ret;
        }
        if (match->me)
                __MOD_INC_USE_COUNT(match->me);
        m->u.kernel.match = match;
        up(&ip6t_mutex);
 
        if (m->u.kernel.match->checkentry
            && !m->u.kernel.match->checkentry(name, ipv6, m->data,
                                              m->u.match_size - sizeof(*m),
                                              hookmask)) {
                if (m->u.kernel.match->me)
                        __MOD_DEC_USE_COUNT(m->u.kernel.match->me);
                duprintf("ip_tables: check failed for `%s'.\n",
                         m->u.kernel.match->name);
                return -EINVAL;
        }
 
        (*i)++;
        return 0;
}
 
static struct ip6t_target ip6t_standard_target;
 
static inline int
check_entry(struct ip6t_entry *e, const char *name, unsigned int size,
            unsigned int *i)
{
        struct ip6t_entry_target *t;
        struct ip6t_target *target;
        int ret;
        unsigned int j;
 
        if (!ip6_checkentry(&e->ipv6)) {
                duprintf("ip_tables: ip check failed %p %s.\n", e, name);
                return -EINVAL;
        }
 
        j = 0;
        ret = IP6T_MATCH_ITERATE(e, check_match, name, &e->ipv6, e->comefrom, &j);
        if (ret != 0)
                goto cleanup_matches;
 
        t = ip6t_get_target(e);
        target = find_target_lock(t->u.user.name, &ret, &ip6t_mutex);
        if (!target) {
                duprintf("check_entry: `%s' not found\n", t->u.user.name);
                goto cleanup_matches;
        }
        if (target->me)
                __MOD_INC_USE_COUNT(target->me);
        t->u.kernel.target = target;
        up(&ip6t_mutex);
 
        if (t->u.kernel.target == &ip6t_standard_target) {
                if (!standard_check(t, size)) {
                        ret = -EINVAL;
                        goto cleanup_matches;
                }
        } else if (t->u.kernel.target->checkentry
                   && !t->u.kernel.target->checkentry(name, e, t->data,
                                                      t->u.target_size
                                                      - sizeof(*t),
                                                      e->comefrom)) {
                if (t->u.kernel.target->me)
                        __MOD_DEC_USE_COUNT(t->u.kernel.target->me);
                duprintf("ip_tables: check failed for `%s'.\n",
                         t->u.kernel.target->name);
                ret = -EINVAL;
                goto cleanup_matches;
        }
 
        (*i)++;
        return 0;
 
 cleanup_matches:
        IP6T_MATCH_ITERATE(e, cleanup_match, &j);
        return ret;
}
 
static inline int
check_entry_size_and_hooks(struct ip6t_entry *e,
                           struct ip6t_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 ip6t_entry) != 0
            || (unsigned char *)e + sizeof(struct ip6t_entry) >= limit) {
                duprintf("Bad offset %p\n", e);
                return -EINVAL;
        }
 
        if (e->next_offset
            < sizeof(struct ip6t_entry) + sizeof(struct ip6t_entry_target)) {
                duprintf("checking: element %p size %u\n",
                         e, e->next_offset);
                return -EINVAL;
        }
 
        /* Check hooks & underflows */
        for (h = 0; h < NF_IP6_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 IP6T_RETURN). --RR */
 
        /* Clear counters and comefrom */
        e->counters = ((struct ip6t_counters) { 0, 0 });
        e->comefrom = 0;
 
        (*i)++;
        return 0;
}
 
static inline int
cleanup_entry(struct ip6t_entry *e, unsigned int *i)
{
        struct ip6t_entry_target *t;
 
        if (i && (*i)-- == 0)
                return 1;
 
        /* Cleanup all matches */
        IP6T_MATCH_ITERATE(e, cleanup_match, NULL);
        t = ip6t_get_target(e);
        if (t->u.kernel.target->destroy)
                t->u.kernel.target->destroy(t->data,
                                            t->u.target_size - sizeof(*t));
        if (t->u.kernel.target->me)
                __MOD_DEC_USE_COUNT(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 ip6t_table_info *newinfo,
                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_IP6_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 = IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size,
                                check_entry_size_and_hooks,
                                newinfo,
                                newinfo->entries,
                                newinfo->entries + 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_IP6_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))
                return -ELOOP;
 
        /* Finally, each sanity check must pass */
        i = 0;
        ret = IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size,
                                check_entry, name, size, &i);
 
        if (ret != 0) {
                IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size,
                                  cleanup_entry, &i);
                return ret;
        }
 
        /* And one copy for every other CPU */
        for (i = 1; i < smp_num_cpus; i++) {
                memcpy(newinfo->entries + SMP_ALIGN(newinfo->size)*i,
                       newinfo->entries,
                       SMP_ALIGN(newinfo->size));
        }
 
        return ret;
}
 
static struct ip6t_table_info *
replace_table(struct ip6t_table *table,
              unsigned int num_counters,
              struct ip6t_table_info *newinfo,
              int *error)
{
        struct ip6t_table_info *oldinfo;
 
#ifdef CONFIG_NETFILTER_DEBUG
        {
                struct ip6t_entry *table_base;
                unsigned int i;
 
                for (i = 0; i < smp_num_cpus; i++) {
                        table_base =
                                (void *)newinfo->entries
                                + TABLE_OFFSET(newinfo, i);
 
                        table_base->comefrom = 0xdead57ac;
                }
        }
#endif
 
        /* Do the substitution. */
        write_lock_bh(&table->lock);
        /* Check inside lock: is the old number correct? */
        if (num_counters != table->private->number) {
                duprintf("num_counters != table->private->number (%u/%u)\n",
                         num_counters, table->private->number);
                write_unlock_bh(&table->lock);
                *error = -EAGAIN;
                return NULL;
        }
        oldinfo = table->private;
        table->private = newinfo;
        newinfo->initial_entries = oldinfo->initial_entries;
        write_unlock_bh(&table->lock);
 
        return oldinfo;
}
 
/* Gets counters. */
static inline int
add_entry_to_counter(const struct ip6t_entry *e,
                     struct ip6t_counters total[],
                     unsigned int *i)
{
        ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);
 
        (*i)++;
        return 0;
}
 
static void
get_counters(const struct ip6t_table_info *t,
             struct ip6t_counters counters[])
{
        unsigned int cpu;
        unsigned int i;
 
        for (cpu = 0; cpu < smp_num_cpus; cpu++) {
                i = 0;
                IP6T_ENTRY_ITERATE(t->entries + TABLE_OFFSET(t, cpu),
                                  t->size,
                                  add_entry_to_counter,
                                  counters,
                                  &i);
        }
}
 
static int
copy_entries_to_user(unsigned int total_size,
                     struct ip6t_table *table,
                     void *userptr)
{
        unsigned int off, num, countersize;
        struct ip6t_entry *e;
        struct ip6t_counters *counters;
        int ret = 0;
 
        /* We need atomic snapshot of counters: rest doesn't change
           (other than comefrom, which userspace doesn't care
           about). */
        countersize = sizeof(struct ip6t_counters) * table->private->number;
        counters = vmalloc(countersize);
 
        if (counters == NULL)
                return -ENOMEM;
 
        /* First, sum counters... */
        memset(counters, 0, countersize);
        write_lock_bh(&table->lock);
        get_counters(table->private, counters);
        write_unlock_bh(&table->lock);
 
        /* ... then copy entire thing from CPU 0... */
        if (copy_to_user(userptr, table->private->entries, 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 ip6t_entry_match *m;
                struct ip6t_entry_target *t;
 
                e = (struct ip6t_entry *)(table->private->entries + off);
                if (copy_to_user(userptr + off
                                 + offsetof(struct ip6t_entry, counters),
                                 &counters[num],
                                 sizeof(counters[num])) != 0) {
                        ret = -EFAULT;
                        goto free_counters;
                }
 
                for (i = sizeof(struct ip6t_entry);
                     i < e->target_offset;
                     i += m->u.match_size) {
                        m = (void *)e + i;
 
                        if (copy_to_user(userptr + off + i
                                         + offsetof(struct ip6t_entry_match,
                                                    u.user.name),
                                         m->u.kernel.match->name,
                                         strlen(m->u.kernel.match->name)+1)
                            != 0) {
                                ret = -EFAULT;
                                goto free_counters;
                        }
                }
 
                t = ip6t_get_target(e);
                if (copy_to_user(userptr + off + e->target_offset
                                 + offsetof(struct ip6t_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;
}
 
static int
get_entries(const struct ip6t_get_entries *entries,
            struct ip6t_get_entries *uptr)
{
        int ret;
        struct ip6t_table *t;
 
        t = find_table_lock(entries->name, &ret, &ip6t_mutex);
        if (t) {
                duprintf("t->private->number = %u\n",
                         t->private->number);
                if (entries->size == t->private->size)
                        ret = copy_entries_to_user(t->private->size,
                                                   t, uptr->entrytable);
                else {
                        duprintf("get_entries: I've got %u not %u!\n",
                                 t->private->size,
                                 entries->size);
                        ret = -EINVAL;
                }
                up(&ip6t_mutex);
        } else
                duprintf("get_entries: Can't find %s!\n",
                         entries->name);
 
        return ret;
}
 
static int
do_replace(void *user, unsigned int len)
{
        int ret;
        struct ip6t_replace tmp;
        struct ip6t_table *t;
        struct ip6t_table_info *newinfo, *oldinfo;
        struct ip6t_counters *counters;
 
        if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
                return -EFAULT;
 
        /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
        if ((SMP_ALIGN(tmp.size) >> PAGE_SHIFT) + 2 > num_physpages)
                return -ENOMEM;
 
        newinfo = vmalloc(sizeof(struct ip6t_table_info)
                          + SMP_ALIGN(tmp.size) * smp_num_cpus);
        if (!newinfo)
                return -ENOMEM;
 
        if (copy_from_user(newinfo->entries, user + sizeof(tmp),
                           tmp.size) != 0) {
                ret = -EFAULT;
                goto free_newinfo;
        }
 
        counters = vmalloc(tmp.num_counters * sizeof(struct ip6t_counters));
        if (!counters) {
                ret = -ENOMEM;
                goto free_newinfo;
        }
        memset(counters, 0, tmp.num_counters * sizeof(struct ip6t_counters));
 
        ret = translate_table(tmp.name, tmp.valid_hooks,
                              newinfo, tmp.size, tmp.num_entries,
                              tmp.hook_entry, tmp.underflow);
        if (ret != 0)
                goto free_newinfo_counters;
 
        duprintf("ip_tables: Translated table\n");
 
        t = find_table_lock(tmp.name, &ret, &ip6t_mutex);
        if (!t)
                goto free_newinfo_counters_untrans;
 
        /* You lied! */
        if (tmp.valid_hooks != t->valid_hooks) {
                duprintf("Valid hook crap: %08X vs %08X\n",
                         tmp.valid_hooks, t->valid_hooks);
                ret = -EINVAL;
                goto free_newinfo_counters_untrans_unlock;
        }
 
        oldinfo = replace_table(t, tmp.num_counters, newinfo, &ret);
        if (!oldinfo)
                goto free_newinfo_counters_untrans_unlock;
 
        /* 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 (t->me && (oldinfo->number <= oldinfo->initial_entries) &&
            (newinfo->number > oldinfo->initial_entries))
                __MOD_INC_USE_COUNT(t->me);
        else if (t->me && (oldinfo->number > oldinfo->initial_entries) &&
                 (newinfo->number <= oldinfo->initial_entries))
                __MOD_DEC_USE_COUNT(t->me);
 
        /* Get the old counters. */
        get_counters(oldinfo, counters);
        /* Decrease module usage counts and free resource */
        IP6T_ENTRY_ITERATE(oldinfo->entries, oldinfo->size, cleanup_entry,NULL);
        vfree(oldinfo);
        /* Silent error: too late now. */
        copy_to_user(tmp.counters, counters,
                     sizeof(struct ip6t_counters) * tmp.num_counters);
        vfree(counters);
        up(&ip6t_mutex);
        return 0;
 
 free_newinfo_counters_untrans_unlock:
        up(&ip6t_mutex);
 free_newinfo_counters_untrans:
        IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size, cleanup_entry,NULL);
 free_newinfo_counters:
        vfree(counters);
 free_newinfo:
        vfree(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 ip6t_entry *e,
                     const struct ip6t_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, unsigned int len)
{
        unsigned int i;
        struct ip6t_counters_info tmp, *paddc;
        struct ip6t_table *t;
        int ret;
 
        if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
                return -EFAULT;
 
        if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct ip6t_counters))
                return -EINVAL;
 
        paddc = vmalloc(len);
        if (!paddc)
                return -ENOMEM;
 
        if (copy_from_user(paddc, user, len) != 0) {
                ret = -EFAULT;
                goto free;
        }
 
        t = find_table_lock(tmp.name, &ret, &ip6t_mutex);
        if (!t)
                goto free;
 
        write_lock_bh(&t->lock);
        if (t->private->number != paddc->num_counters) {
                ret = -EINVAL;
                goto unlock_up_free;
        }
 
        i = 0;
        IP6T_ENTRY_ITERATE(t->private->entries,
                          t->private->size,
                          add_counter_to_entry,
                          paddc->counters,
                          &i);
 unlock_up_free:
        write_unlock_bh(&t->lock);
        up(&ip6t_mutex);
 free:
        vfree(paddc);
 
        return ret;
}
 
static int
do_ip6t_set_ctl(struct sock *sk,        int cmd, void *user, unsigned int len)
{
        int ret;
 
        if (!capable(CAP_NET_ADMIN))
                return -EPERM;
 
        switch (cmd) {
        case IP6T_SO_SET_REPLACE:
                ret = do_replace(user, len);
                break;
 
        case IP6T_SO_SET_ADD_COUNTERS:
                ret = do_add_counters(user, len);
                break;
 
        default:
                duprintf("do_ip6t_set_ctl:  unknown request %i\n", cmd);
                ret = -EINVAL;
        }
 
        return ret;
}
 
static int
do_ip6t_get_ctl(struct sock *sk, int cmd, void *user, int *len)
{
        int ret;
 
        if (!capable(CAP_NET_ADMIN))
                return -EPERM;
 
        switch (cmd) {
        case IP6T_SO_GET_INFO: {
                char name[IP6T_TABLE_MAXNAMELEN];
                struct ip6t_table *t;
 
                if (*len != sizeof(struct ip6t_getinfo)) {
                        duprintf("length %u != %u\n", *len,
                                 sizeof(struct ip6t_getinfo));
                        ret = -EINVAL;
                        break;
                }
 
                if (copy_from_user(name, user, sizeof(name)) != 0) {
                        ret = -EFAULT;
                        break;
                }
                name[IP6T_TABLE_MAXNAMELEN-1] = '\0';
                t = find_table_lock(name, &ret, &ip6t_mutex);
                if (t) {
                        struct ip6t_getinfo info;
 
                        info.valid_hooks = t->valid_hooks;
                        memcpy(info.hook_entry, t->private->hook_entry,
                               sizeof(info.hook_entry));
                        memcpy(info.underflow, t->private->underflow,
                               sizeof(info.underflow));
                        info.num_entries = t->private->number;
                        info.size = t->private->size;
                        strcpy(info.name, name);
 
                        if (copy_to_user(user, &info, *len) != 0)
                                ret = -EFAULT;
                        else
                                ret = 0;
 
                        up(&ip6t_mutex);
                }
        }
        break;
 
        case IP6T_SO_GET_ENTRIES: {
                struct ip6t_get_entries get;
 
                if (*len < sizeof(get)) {
                        duprintf("get_entries: %u < %u\n", *len, sizeof(get));
                        ret = -EINVAL;
                } else if (copy_from_user(&get, user, sizeof(get)) != 0) {
                        ret = -EFAULT;
                } else if (*len != sizeof(struct ip6t_get_entries) + get.size) {
                        duprintf("get_entries: %u != %u\n", *len,
                                 sizeof(struct ip6t_get_entries) + get.size);
                        ret = -EINVAL;
                } else
                        ret = get_entries(&get, user);
                break;
        }
 
        default:
                duprintf("do_ip6t_get_ctl: unknown request %i\n", cmd);
                ret = -EINVAL;
        }
 
        return ret;
}
 
/* Registration hooks for targets. */
int
ip6t_register_target(struct ip6t_target *target)
{
        int ret;
 
        MOD_INC_USE_COUNT;
        ret = down_interruptible(&ip6t_mutex);
        if (ret != 0) {
                MOD_DEC_USE_COUNT;
                return ret;
        }
        if (!list_named_insert(&ip6t_target, target)) {
                duprintf("ip6t_register_target: `%s' already in list!\n",
                         target->name);
                ret = -EINVAL;
                MOD_DEC_USE_COUNT;
        }
        up(&ip6t_mutex);
        return ret;
}
 
void
ip6t_unregister_target(struct ip6t_target *target)
{
        down(&ip6t_mutex);
        LIST_DELETE(&ip6t_target, target);
        up(&ip6t_mutex);
        MOD_DEC_USE_COUNT;
}
 
int
ip6t_register_match(struct ip6t_match *match)
{
        int ret;
 
        MOD_INC_USE_COUNT;
        ret = down_interruptible(&ip6t_mutex);
        if (ret != 0) {
                MOD_DEC_USE_COUNT;
                return ret;
        }
        if (!list_named_insert(&ip6t_match, match)) {
                duprintf("ip6t_register_match: `%s' already in list!\n",
                         match->name);
                MOD_DEC_USE_COUNT;
                ret = -EINVAL;
        }
        up(&ip6t_mutex);
 
        return ret;
}
 
void
ip6t_unregister_match(struct ip6t_match *match)
{
        down(&ip6t_mutex);
        LIST_DELETE(&ip6t_match, match);
        up(&ip6t_mutex);
        MOD_DEC_USE_COUNT;
}
 
int ip6t_register_table(struct ip6t_table *table)
{
        int ret;
        struct ip6t_table_info *newinfo;
        static struct ip6t_table_info bootstrap
                = { 0, 0, 0, { 0 }, { 0 }, { } };
 
        MOD_INC_USE_COUNT;
        newinfo = vmalloc(sizeof(struct ip6t_table_info)
                          + SMP_ALIGN(table->table->size) * smp_num_cpus);
        if (!newinfo) {
                ret = -ENOMEM;
                MOD_DEC_USE_COUNT;
                return ret;
        }
        memcpy(newinfo->entries, table->table->entries, table->table->size);
 
        ret = translate_table(table->name, table->valid_hooks,
                              newinfo, table->table->size,
                              table->table->num_entries,
                              table->table->hook_entry,
                              table->table->underflow);
        if (ret != 0) {
                vfree(newinfo);
                MOD_DEC_USE_COUNT;
                return ret;
        }
 
        ret = down_interruptible(&ip6t_mutex);
        if (ret != 0) {
                vfree(newinfo);
                MOD_DEC_USE_COUNT;
                return ret;
        }
 
        /* Don't autoload: we'd eat our tail... */
        if (list_named_find(&ip6t_tables, table->name)) {
                ret = -EEXIST;
                goto free_unlock;
        }
 
        /* Simplifies replace_table code. */
        table->private = &bootstrap;
        if (!replace_table(table, 0, newinfo, &ret))
                goto free_unlock;
 
        duprintf("table->private->number = %u\n",
                 table->private->number);
 
        /* save number of initial entries */
        table->private->initial_entries = table->private->number;
 
        table->lock = RW_LOCK_UNLOCKED;
        list_prepend(&ip6t_tables, table);
 
 unlock:
        up(&ip6t_mutex);
        return ret;
 
 free_unlock:
        vfree(newinfo);
        MOD_DEC_USE_COUNT;
        goto unlock;
}
 
void ip6t_unregister_table(struct ip6t_table *table)
{
        down(&ip6t_mutex);
        LIST_DELETE(&ip6t_tables, table);
        up(&ip6t_mutex);
 
        /* Decrease module usage counts and free resources */
        IP6T_ENTRY_ITERATE(table->private->entries, table->private->size,
                          cleanup_entry, NULL);
        vfree(table->private);
        MOD_DEC_USE_COUNT;
}
 
/* Returns 1 if the port is matched by the range, 0 otherwise */
static inline int
port_match(u_int16_t min, u_int16_t max, u_int16_t port, int invert)
{
        int ret;
 
        ret = (port >= min && port <= max) ^ invert;
        return ret;
}
 
static int
tcp_find_option(u_int8_t option,
                const struct tcphdr *tcp,
                u_int16_t datalen,
                int invert,
                int *hotdrop)
{
        unsigned int i = sizeof(struct tcphdr);
        const u_int8_t *opt = (u_int8_t *)tcp;
 
        duprintf("tcp_match: finding option\n");
        /* If we don't have the whole header, drop packet. */
        if (tcp->doff * 4 < sizeof(struct tcphdr) ||
            tcp->doff * 4 > datalen) {
                *hotdrop = 1;
                return 0;
        }
 
        while (i < tcp->doff * 4) {
                if (opt[i] == option) return !invert;
                if (opt[i] < 2) i++;
                else i += opt[i+1]?:1;
        }
 
        return invert;
}
 
static int
tcp_match(const struct sk_buff *skb,
          const struct net_device *in,
          const struct net_device *out,
          const void *matchinfo,
          int offset,
          const void *hdr,
          u_int16_t datalen,
          int *hotdrop)
{
        const struct tcphdr *tcp;
        const struct ip6t_tcp *tcpinfo = matchinfo;
        int tcpoff;
        u8 nexthdr = skb->nh.ipv6h->nexthdr;
 
        /* To quote Alan:
 
           Don't allow a fragment of TCP 8 bytes in. Nobody normal
           causes this. Its a cracker trying to break in by doing a
           flag overwrite to pass the direction checks.
        */
 
        if (offset == 1) {
                duprintf("Dropping evil TCP offset=1 frag.\n");
                *hotdrop = 1;
                return 0;
        } else if (offset == 0 && datalen < sizeof(struct tcphdr)) {
                /* We've been asked to examine this packet, and we
                   can't.  Hence, no choice but to drop. */
                duprintf("Dropping evil TCP offset=0 tinygram.\n");
                *hotdrop = 1;
                return 0;
        }
 
        tcpoff = (u8*)(skb->nh.ipv6h + 1) - skb->data;
        tcpoff = ipv6_skip_exthdr(skb, tcpoff, &nexthdr, skb->len - tcpoff);
        if (tcpoff < 0 || tcpoff > skb->len) {
                duprintf("tcp_match: cannot skip exthdr. Dropping.\n");
                *hotdrop = 1;
                return 0;
        } else if (nexthdr == IPPROTO_FRAGMENT)
                return 0;
        else if (nexthdr != IPPROTO_TCP ||
                 skb->len - tcpoff < sizeof(struct tcphdr)) {
                /* cannot be occured */
                duprintf("tcp_match: cannot get TCP header. Dropping.\n");
                *hotdrop = 1;
                return 0;
        }
 
        tcp = (struct tcphdr *)(skb->data + tcpoff);
 
        /* FIXME: Try tcp doff >> packet len against various stacks --RR */
 
#define FWINVTCP(bool,invflg) ((bool) ^ !!(tcpinfo->invflags & invflg))
 
        /* Must not be a fragment. */
        return !offset
                && port_match(tcpinfo->spts[0], tcpinfo->spts[1],
                              ntohs(tcp->source),
                              !!(tcpinfo->invflags & IP6T_TCP_INV_SRCPT))
                && port_match(tcpinfo->dpts[0], tcpinfo->dpts[1],
                              ntohs(tcp->dest),
                              !!(tcpinfo->invflags & IP6T_TCP_INV_DSTPT))
                && FWINVTCP((((unsigned char *)tcp)[13]
                             & tcpinfo->flg_mask)
                            == tcpinfo->flg_cmp,
                            IP6T_TCP_INV_FLAGS)
                && (!tcpinfo->option
                    || tcp_find_option(tcpinfo->option, tcp, datalen,
                                       tcpinfo->invflags
                                       & IP6T_TCP_INV_OPTION,
                                       hotdrop));
}
 
/* Called when user tries to insert an entry of this type. */
static int
tcp_checkentry(const char *tablename,
               const struct ip6t_ip6 *ipv6,
               void *matchinfo,
               unsigned int matchsize,
               unsigned int hook_mask)
{
        const struct ip6t_tcp *tcpinfo = matchinfo;
 
        /* Must specify proto == TCP, and no unknown invflags */
        return ipv6->proto == IPPROTO_TCP
                && !(ipv6->invflags & IP6T_INV_PROTO)
                && matchsize == IP6T_ALIGN(sizeof(struct ip6t_tcp))
                && !(tcpinfo->invflags & ~IP6T_TCP_INV_MASK);
}
 
static int
udp_match(const struct sk_buff *skb,
          const struct net_device *in,
          const struct net_device *out,
          const void *matchinfo,
          int offset,
          const void *hdr,
          u_int16_t datalen,
          int *hotdrop)
{
        const struct udphdr *udp;
        const struct ip6t_udp *udpinfo = matchinfo;
        int udpoff;
        u8 nexthdr = skb->nh.ipv6h->nexthdr;
 
        if (offset == 0 && datalen < sizeof(struct udphdr)) {
                /* We've been asked to examine this packet, and we
                   can't.  Hence, no choice but to drop. */
                duprintf("Dropping evil UDP tinygram.\n");
                *hotdrop = 1;
                return 0;
        }
 
        udpoff = (u8*)(skb->nh.ipv6h + 1) - skb->data;
        udpoff = ipv6_skip_exthdr(skb, udpoff, &nexthdr, skb->len - udpoff);
        if (udpoff < 0 || udpoff > skb->len) {
                duprintf("udp_match: cannot skip exthdr. Dropping.\n");
                *hotdrop = 1;
                return 0;
        } else if (nexthdr == IPPROTO_FRAGMENT)
                return 0;
        else if (nexthdr != IPPROTO_UDP ||
                 skb->len - udpoff < sizeof(struct udphdr)) {
                duprintf("udp_match: cannot get UDP header. Dropping.\n");
                *hotdrop = 1;
                return 0;
        }
 
        udp = (struct udphdr *)(skb->data + udpoff);
 
        /* Must not be a fragment. */
        return !offset
                && port_match(udpinfo->spts[0], udpinfo->spts[1],
                              ntohs(udp->source),
                              !!(udpinfo->invflags & IP6T_UDP_INV_SRCPT))
                && port_match(udpinfo->dpts[0], udpinfo->dpts[1],
                              ntohs(udp->dest),
                              !!(udpinfo->invflags & IP6T_UDP_INV_DSTPT));
}
 
/* Called when user tries to insert an entry of this type. */
static int
udp_checkentry(const char *tablename,
               const struct ip6t_ip6 *ipv6,
               void *matchinfo,
               unsigned int matchinfosize,
               unsigned int hook_mask)
{
        const struct ip6t_udp *udpinfo = matchinfo;
 
        /* Must specify proto == UDP, and no unknown invflags */
        if (ipv6->proto != IPPROTO_UDP || (ipv6->invflags & IP6T_INV_PROTO)) {
                duprintf("ip6t_udp: Protocol %u != %u\n", ipv6->proto,
                         IPPROTO_UDP);
                return 0;
        }
        if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_udp))) {
                duprintf("ip6t_udp: matchsize %u != %u\n",
                         matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_udp)));
                return 0;
        }
        if (udpinfo->invflags & ~IP6T_UDP_INV_MASK) {
                duprintf("ip6t_udp: unknown flags %X\n",
                         udpinfo->invflags);
                return 0;
        }
 
        return 1;
}
 
/* Returns 1 if the type and code is matched by the range, 0 otherwise */
static inline int
icmp6_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,
                     int invert)
{
        return (type == test_type && code >= min_code && code <= max_code)
                ^ invert;
}
 
static int
icmp6_match(const struct sk_buff *skb,
           const struct net_device *in,
           const struct net_device *out,
           const void *matchinfo,
           int offset,
           const void *hdr,
           u_int16_t datalen,
           int *hotdrop)
{
        const struct icmp6hdr *icmp = hdr;
        const struct ip6t_icmp *icmpinfo = matchinfo;
 
        if (offset == 0 && datalen < 2) {
                /* 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 = 1;
                return 0;
        }
 
        /* Must not be a fragment. */
        return !offset
                && icmp6_type_code_match(icmpinfo->type,
                                        icmpinfo->code[0],
                                        icmpinfo->code[1],
                                        icmp->icmp6_type, icmp->icmp6_code,
                                        !!(icmpinfo->invflags&IP6T_ICMP_INV));
}
 
/* Called when user tries to insert an entry of this type. */
static int
icmp6_checkentry(const char *tablename,
           const struct ip6t_ip6 *ipv6,
           void *matchinfo,
           unsigned int matchsize,
           unsigned int hook_mask)
{
        const struct ip6t_icmp *icmpinfo = matchinfo;
 
        /* Must specify proto == ICMP, and no unknown invflags */
        return ipv6->proto == IPPROTO_ICMPV6
                && !(ipv6->invflags & IP6T_INV_PROTO)
                && matchsize == IP6T_ALIGN(sizeof(struct ip6t_icmp))
                && !(icmpinfo->invflags & ~IP6T_ICMP_INV);
}
 
/* The built-in targets: standard (NULL) and error. */
static struct ip6t_target ip6t_standard_target
= { { NULL, NULL }, IP6T_STANDARD_TARGET, NULL, NULL, NULL };
static struct ip6t_target ip6t_error_target
= { { NULL, NULL }, IP6T_ERROR_TARGET, ip6t_error, NULL, NULL };
 
static struct nf_sockopt_ops ip6t_sockopts
= { { NULL, NULL }, PF_INET6, IP6T_BASE_CTL, IP6T_SO_SET_MAX+1, do_ip6t_set_ctl,
    IP6T_BASE_CTL, IP6T_SO_GET_MAX+1, do_ip6t_get_ctl, 0, NULL  };
 
static struct ip6t_match tcp_matchstruct
= { { NULL, NULL }, "tcp", &tcp_match, &tcp_checkentry, NULL };
static struct ip6t_match udp_matchstruct
= { { NULL, NULL }, "udp", &udp_match, &udp_checkentry, NULL };
static struct ip6t_match icmp6_matchstruct
= { { NULL, NULL }, "icmp6", &icmp6_match, &icmp6_checkentry, NULL };
 
#ifdef CONFIG_PROC_FS
static inline int print_name(const char *i,
                             off_t start_offset, char *buffer, int length,
                             off_t *pos, unsigned int *count)
{
        if ((*count)++ >= start_offset) {
                unsigned int namelen;
 
                namelen = sprintf(buffer + *pos, "%s\n",
                                  i + sizeof(struct list_head));
                if (*pos + namelen > length) {
                        /* Stop iterating */
                        return 1;
                }
                *pos += namelen;
        }
        return 0;
}
 
static int ip6t_get_tables(char *buffer, char **start, off_t offset, int length)
{
        off_t pos = 0;
        unsigned int count = 0;
 
        if (down_interruptible(&ip6t_mutex) != 0)
                return 0;
 
        LIST_FIND(&ip6t_tables, print_name, char *,
                  offset, buffer, length, &pos, &count);
 
        up(&ip6t_mutex);
 
        /* `start' hack - see fs/proc/generic.c line ~105 */
        *start=(char *)((unsigned long)count-offset);
        return pos;
}
 
static int ip6t_get_targets(char *buffer, char **start, off_t offset, int length)
{
        off_t pos = 0;
        unsigned int count = 0;
 
        if (down_interruptible(&ip6t_mutex) != 0)
                return 0;
 
        LIST_FIND(&ip6t_target, print_name, char *,
                  offset, buffer, length, &pos, &count);
 
        up(&ip6t_mutex);
 
        *start = (char *)((unsigned long)count - offset);
        return pos;
}
 
static int ip6t_get_matches(char *buffer, char **start, off_t offset, int length)
{
        off_t pos = 0;
        unsigned int count = 0;
 
        if (down_interruptible(&ip6t_mutex) != 0)
                return 0;
 
        LIST_FIND(&ip6t_match, print_name, char *,
                  offset, buffer, length, &pos, &count);
 
        up(&ip6t_mutex);
 
        *start = (char *)((unsigned long)count - offset);
        return pos;
}
 
static struct { char *name; get_info_t *get_info; } ip6t_proc_entry[] =
{ { "ip6_tables_names", ip6t_get_tables },
  { "ip6_tables_targets", ip6t_get_targets },
  { "ip6_tables_matches", ip6t_get_matches },
  { NULL, NULL} };
#endif /*CONFIG_PROC_FS*/
 
static int __init init(void)
{
        int ret;
 
        /* Noone else will be downing sem now, so we won't sleep */
        down(&ip6t_mutex);
        list_append(&ip6t_target, &ip6t_standard_target);
        list_append(&ip6t_target, &ip6t_error_target);
        list_append(&ip6t_match, &tcp_matchstruct);
        list_append(&ip6t_match, &udp_matchstruct);
        list_append(&ip6t_match, &icmp6_matchstruct);
        up(&ip6t_mutex);
 
        /* Register setsockopt */
        ret = nf_register_sockopt(&ip6t_sockopts);
        if (ret < 0) {
                duprintf("Unable to register sockopts.\n");
                return ret;
        }
 
#ifdef CONFIG_PROC_FS
        {
                struct proc_dir_entry *proc;
                int i;
 
                for (i = 0; ip6t_proc_entry[i].name; i++) {
                        proc = proc_net_create(ip6t_proc_entry[i].name, 0,
                                               ip6t_proc_entry[i].get_info);
                        if (!proc) {
                                while (--i >= 0)
                                       proc_net_remove(ip6t_proc_entry[i].name);
                                nf_unregister_sockopt(&ip6t_sockopts);
                                return -ENOMEM;
                        }
                        proc->owner = THIS_MODULE;
                }
        }
#endif
 
        printk("ip6_tables: (C) 2000-2002 Netfilter core team\n");
        return 0;
}
 
static void __exit fini(void)
{
        nf_unregister_sockopt(&ip6t_sockopts);
#ifdef CONFIG_PROC_FS
        {
                int i;
                for (i = 0; ip6t_proc_entry[i].name; i++)
                        proc_net_remove(ip6t_proc_entry[i].name);
        }
#endif
}
 
EXPORT_SYMBOL(ip6t_register_table);
EXPORT_SYMBOL(ip6t_unregister_table);
EXPORT_SYMBOL(ip6t_do_table);
EXPORT_SYMBOL(ip6t_register_match);
EXPORT_SYMBOL(ip6t_unregister_match);
EXPORT_SYMBOL(ip6t_register_target);
EXPORT_SYMBOL(ip6t_unregister_target);
EXPORT_SYMBOL(ip6t_ext_hdr);
 
module_init(init);
module_exit(fini);
MODULE_LICENSE("GPL");
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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [ipv6/] [netfilter/] [ip6_tables.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* Packet matching code.`
3			`*`
4			* Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
5			`* Copyright (C) 2000-2002 Netfilter core team <coreteam@netfilter.org>`
6			`*`
7			`* 19 Jan 2002 Harald Welte <laforge@gnumonks.org>`
8			`* - increase module usage count as soon as we have rules inside`
9			`* a table`
10			`* 06 Jun 2002 Andras Kis-Szabo <kisza@sch.bme.hu>`
11			`* - new extension header parser code`
12			`*/`
13			`#include <linux/config.h>`
14			`#include <linux/skbuff.h>`
15			`#include <linux/kmod.h>`
16			`#include <linux/vmalloc.h>`
17			`#include <linux/netdevice.h>`
18			`#include <linux/module.h>`
19			`#include <linux/tcp.h>`
20			`#include <linux/udp.h>`
21			`#include <linux/icmpv6.h>`
22			`#include <net/ip.h>`
23			`#include <asm/uaccess.h>`
24			`#include <asm/semaphore.h>`
25			`#include <linux/proc_fs.h>`
26
27			`#include <linux/netfilter_ipv6/ip6_tables.h>`
28
29			`#define IPV6_HDR_LEN (sizeof(struct ipv6hdr))`
30			`#define IPV6_OPTHDR_LEN (sizeof(struct ipv6_opt_hdr))`
31
32			`/#define DEBUG_IP_FIREWALL/`
33			`/#define DEBUG_ALLOW_ALL/ /* Useful for remote debugging */`
34			`/#define DEBUG_IP_FIREWALL_USER/`
35
36			`#ifdef DEBUG_IP_FIREWALL`
37			`#define dprintf(format, args...) printk(format , ## args)`
38			`#else`
39			`#define dprintf(format, args...)`
40			`#endif`