Subversion Repositories or1k

/*

 * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6

 *

 * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>

 */

#include <linux/module.h>

#include <linux/netfilter_ipv6/ip6_tables.h>

#define MANGLE_VALID_HOOKS ((1 << NF_IP6_PRE_ROUTING) | \

                            (1 << NF_IP6_LOCAL_IN) | \

                            (1 << NF_IP6_FORWARD) | \

                            (1 << NF_IP6_LOCAL_OUT) | \

                            (1 << NF_IP6_POST_ROUTING))

#if 0

#define DEBUGP(x, args...)      printk(KERN_DEBUG x, ## args)

#else

#define DEBUGP(x, args...)

#endif

/* Standard entry. */

struct ip6t_standard

{

        struct ip6t_entry entry;

        struct ip6t_standard_target target;

};

struct ip6t_error_target

{

        struct ip6t_entry_target target;

        char errorname[IP6T_FUNCTION_MAXNAMELEN];

};

struct ip6t_error

{

        struct ip6t_entry entry;

        struct ip6t_error_target target;

};

static struct

{

        struct ip6t_replace repl;

        struct ip6t_standard entries[5];

        struct ip6t_error term;

} initial_table __initdata

= { { "mangle", MANGLE_VALID_HOOKS, 6,

      sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error),

      { [NF_IP6_PRE_ROUTING]    0,

        [NF_IP6_LOCAL_IN]       sizeof(struct ip6t_standard),

        [NF_IP6_FORWARD]        sizeof(struct ip6t_standard) * 2,

        [NF_IP6_LOCAL_OUT]      sizeof(struct ip6t_standard) * 3,

        [NF_IP6_POST_ROUTING]   sizeof(struct ip6t_standard) * 4},

      { [NF_IP6_PRE_ROUTING]    0,

        [NF_IP6_LOCAL_IN]       sizeof(struct ip6t_standard),

        [NF_IP6_FORWARD]        sizeof(struct ip6t_standard) * 2,

        [NF_IP6_LOCAL_OUT]      sizeof(struct ip6t_standard) * 3,

        [NF_IP6_POST_ROUTING]   sizeof(struct ip6t_standard) * 4},

      0, NULL, { } },

    {

            /* PRE_ROUTING */

            { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

                0,

                sizeof(struct ip6t_entry),

                sizeof(struct ip6t_standard),

                0, { 0, 0 }, { } },

              { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },

                -NF_ACCEPT - 1 } },

            /* LOCAL_IN */

            { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

                0,

                sizeof(struct ip6t_entry),

                sizeof(struct ip6t_standard),

                0, { 0, 0 }, { } },

              { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },

                -NF_ACCEPT - 1 } },

            /* FORWARD */

            { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

                0,

                sizeof(struct ip6t_entry),

                sizeof(struct ip6t_standard),

                0, { 0, 0 }, { } },

              { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },

                -NF_ACCEPT - 1 } },

            /* LOCAL_OUT */

            { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

                0,

                sizeof(struct ip6t_entry),

                sizeof(struct ip6t_standard),

                0, { 0, 0 }, { } },

              { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },

                -NF_ACCEPT - 1 } },

            /* POST_ROUTING */

            { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

                0,

                sizeof(struct ip6t_entry),

                sizeof(struct ip6t_standard),

                0, { 0, 0 }, { } },

              { { { { IP6T_ALIGN(sizeof(struct ip6t_standard_target)), "" } }, { } },

                -NF_ACCEPT - 1 } }

    },

    /* ERROR */

    { { { { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, { { { 0 } } }, "", "", { 0 }, { 0 }, 0, 0, 0 },

        0,

        sizeof(struct ip6t_entry),

        sizeof(struct ip6t_error),

        0, { 0, 0 }, { } },

      { { { { IP6T_ALIGN(sizeof(struct ip6t_error_target)), IP6T_ERROR_TARGET } },

          { } },

        "ERROR"

      }

    }

};

static struct ip6t_table packet_mangler

= { { NULL, NULL }, "mangle", &initial_table.repl,

    MANGLE_VALID_HOOKS, RW_LOCK_UNLOCKED, NULL, THIS_MODULE };

/* The work comes in here from netfilter.c. */

static unsigned int

ip6t_route_hook(unsigned int hook,

         struct sk_buff **pskb,

         const struct net_device *in,

         const struct net_device *out,

         int (*okfn)(struct sk_buff *))

{

        return ip6t_do_table(pskb, hook, in, out, &packet_mangler, NULL);

}

static unsigned int

ip6t_local_hook(unsigned int hook,

                   struct sk_buff **pskb,

                   const struct net_device *in,

                   const struct net_device *out,

                   int (*okfn)(struct sk_buff *))

{

        unsigned long nfmark;

        unsigned int ret;

        struct in6_addr saddr, daddr;

        u_int8_t hop_limit;

        u_int32_t flowlabel;

#if 0

        /* root is playing with raw sockets. */

        if ((*pskb)->len < sizeof(struct iphdr)

            || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {

                if (net_ratelimit())

                        printk("ip6t_hook: happy cracking.\n");

                return NF_ACCEPT;

        }

#endif

        /* save source/dest address, nfmark, hoplimit, flowlabel, priority,  */

        memcpy(&saddr, &(*pskb)->nh.ipv6h->saddr, sizeof(saddr));

        memcpy(&daddr, &(*pskb)->nh.ipv6h->daddr, sizeof(daddr));

        nfmark = (*pskb)->nfmark;

        hop_limit = (*pskb)->nh.ipv6h->hop_limit;

        /* flowlabel and prio (includes version, which shouldn't change either */

        flowlabel = *((u_int32_t *) (*pskb)->nh.ipv6h);

        ret = ip6t_do_table(pskb, hook, in, out, &packet_mangler, NULL);

        if (ret != NF_DROP && ret != NF_STOLEN

                && (memcmp(&(*pskb)->nh.ipv6h->saddr, &saddr, sizeof(saddr))

                    || memcmp(&(*pskb)->nh.ipv6h->daddr, &daddr, sizeof(daddr))

                    || (*pskb)->nfmark != nfmark

                    || (*pskb)->nh.ipv6h->hop_limit != hop_limit)) {

                /* something which could affect routing has changed */

                DEBUGP("ip6table_mangle: we'd need to re-route a packet\n");

        }

        return ret;

}

static struct nf_hook_ops ip6t_ops[]

= { { { NULL, NULL }, ip6t_route_hook, PF_INET6, NF_IP6_PRE_ROUTING,  NF_IP6_PRI_MANGLE },

    { { NULL, NULL }, ip6t_local_hook, PF_INET6, NF_IP6_LOCAL_IN,     NF_IP6_PRI_MANGLE },

    { { NULL, NULL }, ip6t_route_hook, PF_INET6, NF_IP6_FORWARD,      NF_IP6_PRI_MANGLE },

    { { NULL, NULL }, ip6t_local_hook, PF_INET6, NF_IP6_LOCAL_OUT,    NF_IP6_PRI_MANGLE },

    { { NULL, NULL }, ip6t_route_hook, PF_INET6, NF_IP6_POST_ROUTING, NF_IP6_PRI_MANGLE }

};

static int __init init(void)

{

        int ret;

        /* Register table */

        ret = ip6t_register_table(&packet_mangler);

        if (ret < 0)

                return ret;

        /* Register hooks */

        ret = nf_register_hook(&ip6t_ops[0]);

        if (ret < 0)

                goto cleanup_table;

        ret = nf_register_hook(&ip6t_ops[1]);

        if (ret < 0)

                goto cleanup_hook0;

        ret = nf_register_hook(&ip6t_ops[2]);

        if (ret < 0)

                goto cleanup_hook1;

        ret = nf_register_hook(&ip6t_ops[3]);

        if (ret < 0)

                goto cleanup_hook2;

        ret = nf_register_hook(&ip6t_ops[4]);

        if (ret < 0)

                goto cleanup_hook3;

        return ret;

 cleanup_hook3:

        nf_unregister_hook(&ip6t_ops[3]);

 cleanup_hook2:

        nf_unregister_hook(&ip6t_ops[2]);

 cleanup_hook1:

        nf_unregister_hook(&ip6t_ops[1]);

 cleanup_hook0:

        nf_unregister_hook(&ip6t_ops[0]);

 cleanup_table:

        ip6t_unregister_table(&packet_mangler);

        return ret;

}

static void __exit fini(void)

{

        unsigned int i;

        for (i = 0; i < sizeof(ip6t_ops)/sizeof(struct nf_hook_ops); i++)

                nf_unregister_hook(&ip6t_ops[i]);

        ip6t_unregister_table(&packet_mangler);

}

module_init(init);

module_exit(fini);

MODULE_LICENSE("GPL");