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/*

 * INET         An implementation of the TCP/IP protocol suite for the LINUX

 *              operating system.  INET is implemented using the  BSD Socket

 *              interface as the means of communication with the user level.

 *

 *              IPv4 Forwarding Information Base: policy rules.

 *

 * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

 *              Thomas Graf <tgraf@suug.ch>

 *

 *              This program is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 * Fixes:

 *              Rani Assaf      :       local_rule cannot be deleted

 *              Marc Boucher    :       routing by fwmark

 */

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/netdevice.h>

#include <linux/netlink.h>

#include <linux/inetdevice.h>

#include <linux/init.h>

#include <linux/list.h>

#include <linux/rcupdate.h>

#include <net/ip.h>

#include <net/route.h>

#include <net/tcp.h>

#include <net/ip_fib.h>

#include <net/fib_rules.h>

static struct fib_rules_ops fib4_rules_ops;

struct fib4_rule

{

        struct fib_rule         common;

        u8                      dst_len;

        u8                      src_len;

        u8                      tos;

        __be32                  src;

        __be32                  srcmask;

        __be32                  dst;

        __be32                  dstmask;

#ifdef CONFIG_NET_CLS_ROUTE

        u32                     tclassid;

#endif

};

#ifdef CONFIG_NET_CLS_ROUTE

u32 fib_rules_tclass(struct fib_result *res)

{

        return res->r ? ((struct fib4_rule *) res->r)->tclassid : 0;

}

#endif

int fib_lookup(struct flowi *flp, struct fib_result *res)

{

        struct fib_lookup_arg arg = {

                .result = res,

        };

        int err;

        err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg);

        res->r = arg.rule;

        return err;

}

static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,

                            int flags, struct fib_lookup_arg *arg)

{

        int err = -EAGAIN;

        struct fib_table *tbl;

        switch (rule->action) {

        case FR_ACT_TO_TBL:

                break;

        case FR_ACT_UNREACHABLE:

                err = -ENETUNREACH;

                goto errout;

        case FR_ACT_PROHIBIT:

                err = -EACCES;

                goto errout;

        case FR_ACT_BLACKHOLE:

        default:

                err = -EINVAL;

                goto errout;

        }

        if ((tbl = fib_get_table(rule->table)) == NULL)

                goto errout;

        err = tbl->tb_lookup(tbl, flp, (struct fib_result *) arg->result);

        if (err > 0)

                err = -EAGAIN;

errout:

        return err;

}

void fib_select_default(const struct flowi *flp, struct fib_result *res)

{

        if (res->r && res->r->action == FR_ACT_TO_TBL &&

            FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {

                struct fib_table *tb;

                if ((tb = fib_get_table(res->r->table)) != NULL)

                        tb->tb_select_default(tb, flp, res);

        }

}

static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)

{

        struct fib4_rule *r = (struct fib4_rule *) rule;

        __be32 daddr = fl->fl4_dst;

        __be32 saddr = fl->fl4_src;

        if (((saddr ^ r->src) & r->srcmask) ||

            ((daddr ^ r->dst) & r->dstmask))

                return 0;

        if (r->tos && (r->tos != fl->fl4_tos))

                return 0;

        return 1;

}

static struct fib_table *fib_empty_table(void)

{

        u32 id;

        for (id = 1; id <= RT_TABLE_MAX; id++)

                if (fib_get_table(id) == NULL)

                        return fib_new_table(id);

        return NULL;

}

static const struct nla_policy fib4_rule_policy[FRA_MAX+1] = {

        FRA_GENERIC_POLICY,

        [FRA_FLOW]      = { .type = NLA_U32 },

};

static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,

                               struct nlmsghdr *nlh, struct fib_rule_hdr *frh,

                               struct nlattr **tb)

{

        int err = -EINVAL;

        struct fib4_rule *rule4 = (struct fib4_rule *) rule;

        if (frh->tos & ~IPTOS_TOS_MASK)

                goto errout;

        if (rule->table == RT_TABLE_UNSPEC) {

                if (rule->action == FR_ACT_TO_TBL) {

                        struct fib_table *table;

                        table = fib_empty_table();

                        if (table == NULL) {

                                err = -ENOBUFS;

                                goto errout;

                        }

                        rule->table = table->tb_id;

                }

        }

        if (frh->src_len)

                rule4->src = nla_get_be32(tb[FRA_SRC]);

        if (frh->dst_len)

                rule4->dst = nla_get_be32(tb[FRA_DST]);

#ifdef CONFIG_NET_CLS_ROUTE

        if (tb[FRA_FLOW])

                rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);

#endif

        rule4->src_len = frh->src_len;

        rule4->srcmask = inet_make_mask(rule4->src_len);

        rule4->dst_len = frh->dst_len;

        rule4->dstmask = inet_make_mask(rule4->dst_len);

        rule4->tos = frh->tos;

        err = 0;

errout:

        return err;

}

static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,

                             struct nlattr **tb)

{

        struct fib4_rule *rule4 = (struct fib4_rule *) rule;

        if (frh->src_len && (rule4->src_len != frh->src_len))

                return 0;

        if (frh->dst_len && (rule4->dst_len != frh->dst_len))

                return 0;

        if (frh->tos && (rule4->tos != frh->tos))

                return 0;

#ifdef CONFIG_NET_CLS_ROUTE

        if (tb[FRA_FLOW] && (rule4->tclassid != nla_get_u32(tb[FRA_FLOW])))

                return 0;

#endif

        if (frh->src_len && (rule4->src != nla_get_be32(tb[FRA_SRC])))

                return 0;

        if (frh->dst_len && (rule4->dst != nla_get_be32(tb[FRA_DST])))

                return 0;

        return 1;

}

static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,

                          struct nlmsghdr *nlh, struct fib_rule_hdr *frh)

{

        struct fib4_rule *rule4 = (struct fib4_rule *) rule;

        frh->family = AF_INET;

        frh->dst_len = rule4->dst_len;

        frh->src_len = rule4->src_len;

        frh->tos = rule4->tos;

        if (rule4->dst_len)

                NLA_PUT_BE32(skb, FRA_DST, rule4->dst);

        if (rule4->src_len)

                NLA_PUT_BE32(skb, FRA_SRC, rule4->src);

#ifdef CONFIG_NET_CLS_ROUTE

        if (rule4->tclassid)

                NLA_PUT_U32(skb, FRA_FLOW, rule4->tclassid);

#endif

        return 0;

nla_put_failure:

        return -ENOBUFS;

}

static u32 fib4_rule_default_pref(void)

{

        struct list_head *pos;

        struct fib_rule *rule;

        if (!list_empty(&fib4_rules_ops.rules_list)) {

                pos = fib4_rules_ops.rules_list.next;

                if (pos->next != &fib4_rules_ops.rules_list) {

                        rule = list_entry(pos->next, struct fib_rule, list);

                        if (rule->pref)

                                return rule->pref - 1;

                }

        }

        return 0;

}

static size_t fib4_rule_nlmsg_payload(struct fib_rule *rule)

{

        return nla_total_size(4) /* dst */

               + nla_total_size(4) /* src */

               + nla_total_size(4); /* flow */

}

static void fib4_rule_flush_cache(void)

{

        rt_cache_flush(-1);

}

static struct fib_rules_ops fib4_rules_ops = {

        .family         = AF_INET,

        .rule_size      = sizeof(struct fib4_rule),

        .addr_size      = sizeof(u32),

        .action         = fib4_rule_action,

        .match          = fib4_rule_match,

        .configure      = fib4_rule_configure,

        .compare        = fib4_rule_compare,

        .fill           = fib4_rule_fill,

        .default_pref   = fib4_rule_default_pref,

        .nlmsg_payload  = fib4_rule_nlmsg_payload,

        .flush_cache    = fib4_rule_flush_cache,

        .nlgroup        = RTNLGRP_IPV4_RULE,

        .policy         = fib4_rule_policy,

        .rules_list     = LIST_HEAD_INIT(fib4_rules_ops.rules_list),

        .owner          = THIS_MODULE,

};

static int __init fib_default_rules_init(void)

{

        int err;

        err = fib_default_rule_add(&fib4_rules_ops, 0,

                                   RT_TABLE_LOCAL, FIB_RULE_PERMANENT);

        if (err < 0)

                return err;

        err = fib_default_rule_add(&fib4_rules_ops, 0x7FFE,

                                   RT_TABLE_MAIN, 0);

        if (err < 0)

                return err;

        err = fib_default_rule_add(&fib4_rules_ops, 0x7FFF,

                                   RT_TABLE_DEFAULT, 0);

        if (err < 0)

                return err;

        return 0;

}

void __init fib4_rules_init(void)

{

        BUG_ON(fib_default_rules_init());

        fib_rules_register(&fib4_rules_ops);

}