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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.

 *

 * Version:     $Id: fib_rules.c,v 1.1.1.1 2004-04-15 01:13:55 phoenix Exp $

 *

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

 *

 *              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/config.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <asm/bitops.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/mm.h>

#include <linux/string.h>

#include <linux/socket.h>

#include <linux/sockios.h>

#include <linux/errno.h>

#include <linux/in.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/if_arp.h>

#include <linux/proc_fs.h>

#include <linux/skbuff.h>

#include <linux/netlink.h>

#include <linux/init.h>

#include <net/ip.h>

#include <net/protocol.h>

#include <net/route.h>

#include <net/tcp.h>

#include <net/sock.h>

#include <net/ip_fib.h>

#define FRprintk(a...)

struct fib_rule

{

        struct fib_rule *r_next;

        atomic_t        r_clntref;

        u32             r_preference;

        unsigned char   r_table;

        unsigned char   r_action;

        unsigned char   r_dst_len;

        unsigned char   r_src_len;

        u32             r_src;

        u32             r_srcmask;

        u32             r_dst;

        u32             r_dstmask;

        u32             r_srcmap;

        u8              r_flags;

        u8              r_tos;

#ifdef CONFIG_IP_ROUTE_FWMARK

        u32             r_fwmark;

#endif

        int             r_ifindex;

#ifdef CONFIG_NET_CLS_ROUTE

        __u32           r_tclassid;

#endif

        char            r_ifname[IFNAMSIZ];

        int             r_dead;

};

static struct fib_rule default_rule = {

        r_clntref:      ATOMIC_INIT(2),

        r_preference:   0x7FFF,

        r_table:        RT_TABLE_DEFAULT,

        r_action:       RTN_UNICAST,

};

static struct fib_rule main_rule = {

        r_next:         &default_rule,

        r_clntref:      ATOMIC_INIT(2),

        r_preference:   0x7FFE,

        r_table:        RT_TABLE_MAIN,

        r_action:       RTN_UNICAST,

};

static struct fib_rule local_rule = {

        r_next:         &main_rule,

        r_clntref:      ATOMIC_INIT(2),

        r_table:        RT_TABLE_LOCAL,

        r_action:       RTN_UNICAST,

};

static struct fib_rule *fib_rules = &local_rule;

static rwlock_t fib_rules_lock = RW_LOCK_UNLOCKED;

int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)

{

        struct rtattr **rta = arg;

        struct rtmsg *rtm = NLMSG_DATA(nlh);

        struct fib_rule *r, **rp;

        int err = -ESRCH;

        for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {

                if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&

                    rtm->rtm_src_len == r->r_src_len &&

                    rtm->rtm_dst_len == r->r_dst_len &&

                    (!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) &&

                    rtm->rtm_tos == r->r_tos &&

#ifdef CONFIG_IP_ROUTE_FWMARK

                    (!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&

#endif

                    (!rtm->rtm_type || rtm->rtm_type == r->r_action) &&

                    (!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&

                    (!rta[RTA_IIF-1] || strcmp(RTA_DATA(rta[RTA_IIF-1]), r->r_ifname) == 0) &&

                    (!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {

                        err = -EPERM;

                        if (r == &local_rule)

                                break;

                        write_lock_bh(&fib_rules_lock);

                        *rp = r->r_next;

                        r->r_dead = 1;

                        write_unlock_bh(&fib_rules_lock);

                        fib_rule_put(r);

                        err = 0;

                        break;

                }

        }

        return err;

}

/* Allocate new unique table id */

static struct fib_table *fib_empty_table(void)

{

        int id;

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

                if (fib_tables[id] == NULL)

                        return __fib_new_table(id);

        return NULL;

}

void fib_rule_put(struct fib_rule *r)

{

        if (atomic_dec_and_test(&r->r_clntref)) {

                if (r->r_dead)

                        kfree(r);

                else

                        printk("Freeing alive rule %p\n", r);

        }

}

int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)

{

        struct rtattr **rta = arg;

        struct rtmsg *rtm = NLMSG_DATA(nlh);

        struct fib_rule *r, *new_r, **rp;

        unsigned char table_id;

        if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||

            (rtm->rtm_tos & ~IPTOS_TOS_MASK))

                return -EINVAL;

        if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)

                return -EINVAL;

        table_id = rtm->rtm_table;

        if (table_id == RT_TABLE_UNSPEC) {

                struct fib_table *table;

                if (rtm->rtm_type == RTN_UNICAST || rtm->rtm_type == RTN_NAT) {

                        if ((table = fib_empty_table()) == NULL)

                                return -ENOBUFS;

                        table_id = table->tb_id;

                }

        }

        new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);

        if (!new_r)

                return -ENOMEM;

        memset(new_r, 0, sizeof(*new_r));

        if (rta[RTA_SRC-1])

                memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);

        if (rta[RTA_DST-1])

                memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4);

        if (rta[RTA_GATEWAY-1])

                memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4);

        new_r->r_src_len = rtm->rtm_src_len;

        new_r->r_dst_len = rtm->rtm_dst_len;

        new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len);

        new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len);

        new_r->r_tos = rtm->rtm_tos;

#ifdef CONFIG_IP_ROUTE_FWMARK

        if (rta[RTA_PROTOINFO-1])

                memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);

#endif

        new_r->r_action = rtm->rtm_type;

        new_r->r_flags = rtm->rtm_flags;

        if (rta[RTA_PRIORITY-1])

                memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);

        new_r->r_table = table_id;

        if (rta[RTA_IIF-1]) {

                struct net_device *dev;

                memcpy(new_r->r_ifname, RTA_DATA(rta[RTA_IIF-1]), IFNAMSIZ);

                new_r->r_ifname[IFNAMSIZ-1] = 0;

                new_r->r_ifindex = -1;

                dev = __dev_get_by_name(new_r->r_ifname);

                if (dev)

                        new_r->r_ifindex = dev->ifindex;

        }

#ifdef CONFIG_NET_CLS_ROUTE

        if (rta[RTA_FLOW-1])

                memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);

#endif

        rp = &fib_rules;

        if (!new_r->r_preference) {

                r = fib_rules;

                if (r && (r = r->r_next) != NULL) {

                        rp = &fib_rules->r_next;

                        if (r->r_preference)

                                new_r->r_preference = r->r_preference - 1;

                }

        }

        while ( (r = *rp) != NULL ) {

                if (r->r_preference > new_r->r_preference)

                        break;

                rp = &r->r_next;

        }

        new_r->r_next = r;

        atomic_inc(&new_r->r_clntref);

        write_lock_bh(&fib_rules_lock);

        *rp = new_r;

        write_unlock_bh(&fib_rules_lock);

        return 0;

}

u32 fib_rules_map_destination(u32 daddr, struct fib_result *res)

{

        u32 mask = inet_make_mask(res->prefixlen);

        return (daddr&~mask)|res->fi->fib_nh->nh_gw;

}

u32 fib_rules_policy(u32 saddr, struct fib_result *res, unsigned *flags)

{

        struct fib_rule *r = res->r;

        if (r->r_action == RTN_NAT) {

                int addrtype = inet_addr_type(r->r_srcmap);

                if (addrtype == RTN_NAT) {

                        /* Packet is from  translated source; remember it */

                        saddr = (saddr&~r->r_srcmask)|r->r_srcmap;

                        *flags |= RTCF_SNAT;

                } else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {

                        /* Packet is from masqueraded source; remember it */

                        saddr = r->r_srcmap;

                        *flags |= RTCF_MASQ;

                }

        }

        return saddr;

}

#ifdef CONFIG_NET_CLS_ROUTE

u32 fib_rules_tclass(struct fib_result *res)

{

        if (res->r)

                return res->r->r_tclassid;

        return 0;

}

#endif

static void fib_rules_detach(struct net_device *dev)

{

        struct fib_rule *r;

        for (r=fib_rules; r; r=r->r_next) {

                if (r->r_ifindex == dev->ifindex) {

                        write_lock_bh(&fib_rules_lock);

                        r->r_ifindex = -1;

                        write_unlock_bh(&fib_rules_lock);

                }

        }

}

static void fib_rules_attach(struct net_device *dev)

{

        struct fib_rule *r;

        for (r=fib_rules; r; r=r->r_next) {

                if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {

                        write_lock_bh(&fib_rules_lock);

                        r->r_ifindex = dev->ifindex;

                        write_unlock_bh(&fib_rules_lock);

                }

        }

}

int fib_lookup(const struct rt_key *key, struct fib_result *res)

{

        int err;

        struct fib_rule *r, *policy;

        struct fib_table *tb;

        u32 daddr = key->dst;

        u32 saddr = key->src;

FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",

        NIPQUAD(key->dst), NIPQUAD(key->src));

        read_lock(&fib_rules_lock);

        for (r = fib_rules; r; r=r->r_next) {

                if (((saddr^r->r_src) & r->r_srcmask) ||

                    ((daddr^r->r_dst) & r->r_dstmask) ||

#ifdef CONFIG_IP_ROUTE_TOS

                    (r->r_tos && r->r_tos != key->tos) ||

#endif

#ifdef CONFIG_IP_ROUTE_FWMARK

                    (r->r_fwmark && r->r_fwmark != key->fwmark) ||

#endif

                    (r->r_ifindex && r->r_ifindex != key->iif))

                        continue;

FRprintk("tb %d r %d ", r->r_table, r->r_action);

                switch (r->r_action) {

                case RTN_UNICAST:

                case RTN_NAT:

                        policy = r;

                        break;

                case RTN_UNREACHABLE:

                        read_unlock(&fib_rules_lock);

                        return -ENETUNREACH;

                default:

                case RTN_BLACKHOLE:

                        read_unlock(&fib_rules_lock);

                        return -EINVAL;

                case RTN_PROHIBIT:

                        read_unlock(&fib_rules_lock);

                        return -EACCES;

                }

                if ((tb = fib_get_table(r->r_table)) == NULL)

                        continue;

                err = tb->tb_lookup(tb, key, res);

                if (err == 0) {

                        res->r = policy;

                        if (policy)

                                atomic_inc(&policy->r_clntref);

                        read_unlock(&fib_rules_lock);

                        return 0;

                }

                if (err < 0 && err != -EAGAIN) {

                        read_unlock(&fib_rules_lock);

                        return err;

                }

        }

FRprintk("FAILURE\n");

        read_unlock(&fib_rules_lock);

        return -ENETUNREACH;

}

void fib_select_default(const struct rt_key *key, struct fib_result *res)

{

        if (res->r && res->r->r_action == RTN_UNICAST &&

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

                struct fib_table *tb;

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

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

        }

}

static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)

{

        struct net_device *dev = ptr;

        if (event == NETDEV_UNREGISTER)

                fib_rules_detach(dev);

        else if (event == NETDEV_REGISTER)

                fib_rules_attach(dev);

        return NOTIFY_DONE;

}

struct notifier_block fib_rules_notifier = {

        notifier_call:  fib_rules_event,

};

static __inline__ int inet_fill_rule(struct sk_buff *skb,

                                     struct fib_rule *r,

                                     struct netlink_callback *cb)

{

        struct rtmsg *rtm;

        struct nlmsghdr  *nlh;

        unsigned char    *b = skb->tail;

        nlh = NLMSG_PUT(skb, NETLINK_CREDS(cb->skb)->pid, cb->nlh->nlmsg_seq, RTM_NEWRULE, sizeof(*rtm));

        rtm = NLMSG_DATA(nlh);

        rtm->rtm_family = AF_INET;

        rtm->rtm_dst_len = r->r_dst_len;

        rtm->rtm_src_len = r->r_src_len;

        rtm->rtm_tos = r->r_tos;

#ifdef CONFIG_IP_ROUTE_FWMARK

        if (r->r_fwmark)

                RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);

#endif

        rtm->rtm_table = r->r_table;

        rtm->rtm_protocol = 0;

        rtm->rtm_scope = 0;

        rtm->rtm_type = r->r_action;

        rtm->rtm_flags = r->r_flags;

        if (r->r_dst_len)

                RTA_PUT(skb, RTA_DST, 4, &r->r_dst);

        if (r->r_src_len)

                RTA_PUT(skb, RTA_SRC, 4, &r->r_src);

        if (r->r_ifname[0])

                RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);

        if (r->r_preference)

                RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);

        if (r->r_srcmap)

                RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap);

#ifdef CONFIG_NET_CLS_ROUTE

        if (r->r_tclassid)

                RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid);

#endif

        nlh->nlmsg_len = skb->tail - b;

        return skb->len;

nlmsg_failure:

rtattr_failure:

        skb_trim(skb, b - skb->data);

        return -1;

}

int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)

{

        int idx;

        int s_idx = cb->args[0];

        struct fib_rule *r;

        read_lock(&fib_rules_lock);

        for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {

                if (idx < s_idx)

                        continue;

                if (inet_fill_rule(skb, r, cb) < 0)

                        break;

        }

        read_unlock(&fib_rules_lock);

        cb->args[0] = idx;

        return skb->len;

}

void __init fib_rules_init(void)

{

        register_netdevice_notifier(&fib_rules_notifier);

}