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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: FIB frontend.

 *

 * Version:     $Id: fib_frontend.c,v 1.1.1.1 2004-04-15 01:13:58 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.

 */

#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/icmp.h>

#include <net/arp.h>

#include <net/ip_fib.h>

#define FFprint(a...) printk(KERN_DEBUG a)

#ifndef CONFIG_IP_MULTIPLE_TABLES

#define RT_TABLE_MIN RT_TABLE_MAIN

struct fib_table *local_table;

struct fib_table *main_table;

#else

#define RT_TABLE_MIN 1

struct fib_table *fib_tables[RT_TABLE_MAX+1];

struct fib_table *__fib_new_table(int id)

{

        struct fib_table *tb;

        tb = fib_hash_init(id);

        if (!tb)

                return NULL;

        fib_tables[id] = tb;

        return tb;

}

#endif /* CONFIG_IP_MULTIPLE_TABLES */

void fib_flush(void)

{

        int flushed = 0;

#ifdef CONFIG_IP_MULTIPLE_TABLES

        struct fib_table *tb;

        int id;

        for (id = RT_TABLE_MAX; id>0; id--) {

                if ((tb = fib_get_table(id))==NULL)

                        continue;

                flushed += tb->tb_flush(tb);

        }

#else /* CONFIG_IP_MULTIPLE_TABLES */

        flushed += main_table->tb_flush(main_table);

        flushed += local_table->tb_flush(local_table);

#endif /* CONFIG_IP_MULTIPLE_TABLES */

        if (flushed)

                rt_cache_flush(-1);

}

#ifdef CONFIG_PROC_FS

/*

 *      Called from the PROCfs module. This outputs /proc/net/route.

 *

 *      It always works in backward compatibility mode.

 *      The format of the file is not supposed to be changed.

 */

static int

fib_get_procinfo(char *buffer, char **start, off_t offset, int length)

{

        int first = offset/128;

        char *ptr = buffer;

        int count = (length+127)/128;

        int len;

        *start = buffer + offset%128;

        if (--first < 0) {

                sprintf(buffer, "%-127s\n", "Iface\tDestination\tGateway \tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU\tWindow\tIRTT");

                --count;

                ptr += 128;

                first = 0;

        }

        if (main_table && count > 0) {

                int n = main_table->tb_get_info(main_table, ptr, first, count);

                count -= n;

                ptr += n*128;

        }

        len = ptr - *start;

        if (len >= length)

                return length;

        if (len >= 0)

                return len;

        return 0;

}

#endif /* CONFIG_PROC_FS */

/*

 *      Find the first device with a given source address.

 */

struct net_device * ip_dev_find(u32 addr)

{

        struct rt_key key;

        struct fib_result res;

        struct net_device *dev = NULL;

        memset(&key, 0, sizeof(key));

        key.dst = addr;

#ifdef CONFIG_IP_MULTIPLE_TABLES

        res.r = NULL;

#endif

        if (!local_table || local_table->tb_lookup(local_table, &key, &res)) {

                return NULL;

        }

        if (res.type != RTN_LOCAL)

                goto out;

        dev = FIB_RES_DEV(res);

        if (dev)

                dev_hold(dev);

out:

        fib_res_put(&res);

        return dev;

}

unsigned inet_addr_type(u32 addr)

{

        struct rt_key           key;

        struct fib_result       res;

        unsigned ret = RTN_BROADCAST;

        if (ZERONET(addr) || BADCLASS(addr))

                return RTN_BROADCAST;

        if (MULTICAST(addr))

                return RTN_MULTICAST;

        memset(&key, 0, sizeof(key));

        key.dst = addr;

#ifdef CONFIG_IP_MULTIPLE_TABLES

        res.r = NULL;

#endif

        if (local_table) {

                ret = RTN_UNICAST;

                if (local_table->tb_lookup(local_table, &key, &res) == 0) {

                        ret = res.type;

                        fib_res_put(&res);

                }

        }

        return ret;

}

/* Given (packet source, input interface) and optional (dst, oif, tos):

   - (main) check, that source is valid i.e. not broadcast or our local

     address.

   - figure out what "logical" interface this packet arrived

     and calculate "specific destination" address.

   - check, that packet arrived from expected physical interface.

 */

int fib_validate_source(u32 src, u32 dst, u8 tos, int oif,

                        struct net_device *dev, u32 *spec_dst, u32 *itag)

{

        struct in_device *in_dev;

        struct rt_key key;

        struct fib_result res;

        int no_addr, rpf;

        int ret;

        key.dst = src;

        key.src = dst;

        key.tos = tos;

        key.oif = 0;

        key.iif = oif;

        key.scope = RT_SCOPE_UNIVERSE;

        no_addr = rpf = 0;

        read_lock(&inetdev_lock);

        in_dev = __in_dev_get(dev);

        if (in_dev) {

                no_addr = in_dev->ifa_list == NULL;

                rpf = IN_DEV_RPFILTER(in_dev);

        }

        read_unlock(&inetdev_lock);

        if (in_dev == NULL)

                goto e_inval;

        if (fib_lookup(&key, &res))

                goto last_resort;

        if (res.type != RTN_UNICAST)

                goto e_inval_res;

        *spec_dst = FIB_RES_PREFSRC(res);

        fib_combine_itag(itag, &res);

#ifdef CONFIG_IP_ROUTE_MULTIPATH

        if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1)

#else

        if (FIB_RES_DEV(res) == dev)

#endif

        {

                ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;

                fib_res_put(&res);

                return ret;

        }

        fib_res_put(&res);

        if (no_addr)

                goto last_resort;

        if (rpf)

                goto e_inval;

        key.oif = dev->ifindex;

        ret = 0;

        if (fib_lookup(&key, &res) == 0) {

                if (res.type == RTN_UNICAST) {

                        *spec_dst = FIB_RES_PREFSRC(res);

                        ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;

                }

                fib_res_put(&res);

        }

        return ret;

last_resort:

        if (rpf)

                goto e_inval;

        *spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);

        *itag = 0;

        return 0;

e_inval_res:

        fib_res_put(&res);

e_inval:

        return -EINVAL;

}

#ifndef CONFIG_IP_NOSIOCRT

/*

 *      Handle IP routing ioctl calls. These are used to manipulate the routing tables

 */

int ip_rt_ioctl(unsigned int cmd, void *arg)

{

        int err;

        struct kern_rta rta;

        struct rtentry  r;

        struct {

                struct nlmsghdr nlh;

                struct rtmsg    rtm;

        } req;

        switch (cmd) {

        case SIOCADDRT:         /* Add a route */

        case SIOCDELRT:         /* Delete a route */

                if (!capable(CAP_NET_ADMIN))

                        return -EPERM;

                if (copy_from_user(&r, arg, sizeof(struct rtentry)))

                        return -EFAULT;

                rtnl_lock();

                err = fib_convert_rtentry(cmd, &req.nlh, &req.rtm, &rta, &r);

                if (err == 0) {

                        if (cmd == SIOCDELRT) {

                                struct fib_table *tb = fib_get_table(req.rtm.rtm_table);

                                err = -ESRCH;

                                if (tb)

                                        err = tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL);

                        } else {

                                struct fib_table *tb = fib_new_table(req.rtm.rtm_table);

                                err = -ENOBUFS;

                                if (tb)

                                        err = tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL);

                        }

                        if (rta.rta_mx)

                                kfree(rta.rta_mx);

                }

                rtnl_unlock();

                return err;

        }

        return -EINVAL;

}

#else

int ip_rt_ioctl(unsigned int cmd, void *arg)

{

        return -EINVAL;

}

#endif

static int inet_check_attr(struct rtmsg *r, struct rtattr **rta)

{

        int i;

        for (i=1; i<=RTA_MAX; i++) {

                struct rtattr *attr = rta[i-1];

                if (attr) {

                        if (RTA_PAYLOAD(attr) < 4)

                                return -EINVAL;

                        if (i != RTA_MULTIPATH && i != RTA_METRICS)

                                rta[i-1] = (struct rtattr*)RTA_DATA(attr);

                }

        }

        return 0;

}

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

{

        struct fib_table * tb;

        struct rtattr **rta = arg;

        struct rtmsg *r = NLMSG_DATA(nlh);

        if (inet_check_attr(r, rta))

                return -EINVAL;

        tb = fib_get_table(r->rtm_table);

        if (tb)

                return tb->tb_delete(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb));

        return -ESRCH;

}

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

{

        struct fib_table * tb;

        struct rtattr **rta = arg;

        struct rtmsg *r = NLMSG_DATA(nlh);

        if (inet_check_attr(r, rta))

                return -EINVAL;

        tb = fib_new_table(r->rtm_table);

        if (tb)

                return tb->tb_insert(tb, r, (struct kern_rta*)rta, nlh, &NETLINK_CB(skb));

        return -ENOBUFS;

}

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

{

        int t;

        int s_t;

        struct fib_table *tb;

        if (NLMSG_PAYLOAD(cb->nlh, 0) >= sizeof(struct rtmsg) &&

            ((struct rtmsg*)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED)

                return ip_rt_dump(skb, cb);

        s_t = cb->args[0];

        if (s_t == 0)

                s_t = cb->args[0] = RT_TABLE_MIN;

        for (t=s_t; t<=RT_TABLE_MAX; t++) {

                if (t < s_t) continue;

                if (t > s_t)

                        memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));

                if ((tb = fib_get_table(t))==NULL)

                        continue;

                if (tb->tb_dump(tb, skb, cb) < 0)

                        break;

        }

        cb->args[0] = t;

        return skb->len;

}

/* Prepare and feed intra-kernel routing request.

   Really, it should be netlink message, but :-( netlink

   can be not configured, so that we feed it directly

   to fib engine. It is legal, because all events occur

   only when netlink is already locked.

 */

static void fib_magic(int cmd, int type, u32 dst, int dst_len, struct in_ifaddr *ifa)

{

        struct fib_table * tb;

        struct {

                struct nlmsghdr nlh;

                struct rtmsg    rtm;

        } req;

        struct kern_rta rta;

        memset(&req.rtm, 0, sizeof(req.rtm));

        memset(&rta, 0, sizeof(rta));

        if (type == RTN_UNICAST)

                tb = fib_new_table(RT_TABLE_MAIN);

        else

                tb = fib_new_table(RT_TABLE_LOCAL);

        if (tb == NULL)

                return;

        req.nlh.nlmsg_len = sizeof(req);

        req.nlh.nlmsg_type = cmd;

        req.nlh.nlmsg_flags = NLM_F_REQUEST|NLM_F_CREATE|NLM_F_APPEND;

        req.nlh.nlmsg_pid = 0;

        req.nlh.nlmsg_seq = 0;

        req.rtm.rtm_dst_len = dst_len;

        req.rtm.rtm_table = tb->tb_id;

        req.rtm.rtm_protocol = RTPROT_KERNEL;

        req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);

        req.rtm.rtm_type = type;

        rta.rta_dst = &dst;

        rta.rta_prefsrc = &ifa->ifa_local;

        rta.rta_oif = &ifa->ifa_dev->dev->ifindex;

        if (cmd == RTM_NEWROUTE)

                tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL);

        else

                tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL);

}

static void fib_add_ifaddr(struct in_ifaddr *ifa)

{

        struct in_device *in_dev = ifa->ifa_dev;

        struct net_device *dev = in_dev->dev;

        struct in_ifaddr *prim = ifa;

        u32 mask = ifa->ifa_mask;

        u32 addr = ifa->ifa_local;

        u32 prefix = ifa->ifa_address&mask;

        if (ifa->ifa_flags&IFA_F_SECONDARY) {

                prim = inet_ifa_byprefix(in_dev, prefix, mask);

                if (prim == NULL) {

                        printk(KERN_DEBUG "fib_add_ifaddr: bug: prim == NULL\n");

                        return;

                }

        }

        fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);

        if (!(dev->flags&IFF_UP))

                return;

        /* Add broadcast address, if it is explicitly assigned. */

        if (ifa->ifa_broadcast && ifa->ifa_broadcast != 0xFFFFFFFF)

                fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);

        if (!ZERONET(prefix) && !(ifa->ifa_flags&IFA_F_SECONDARY) &&

            (prefix != addr || ifa->ifa_prefixlen < 32)) {

                fib_magic(RTM_NEWROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :

                          RTN_UNICAST, prefix, ifa->ifa_prefixlen, prim);

                /* Add network specific broadcasts, when it takes a sense */

                if (ifa->ifa_prefixlen < 31) {

                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);

                        fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix|~mask, 32, prim);

                }

        }

}

static void fib_del_ifaddr(struct in_ifaddr *ifa)

{

        struct in_device *in_dev = ifa->ifa_dev;

        struct net_device *dev = in_dev->dev;

        struct in_ifaddr *ifa1;

        struct in_ifaddr *prim = ifa;

        u32 brd = ifa->ifa_address|~ifa->ifa_mask;

        u32 any = ifa->ifa_address&ifa->ifa_mask;

#define LOCAL_OK        1

#define BRD_OK          2

#define BRD0_OK         4

#define BRD1_OK         8

        unsigned ok = 0;

        if (!(ifa->ifa_flags&IFA_F_SECONDARY))

                fib_magic(RTM_DELROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :

                          RTN_UNICAST, any, ifa->ifa_prefixlen, prim);

        else {

                prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);

                if (prim == NULL) {

                        printk(KERN_DEBUG "fib_del_ifaddr: bug: prim == NULL\n");

                        return;

                }

        }

        /* Deletion is more complicated than add.

           We should take care of not to delete too much :-)

           Scan address list to be sure that addresses are really gone.

         */

        for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {

                if (ifa->ifa_local == ifa1->ifa_local)

                        ok |= LOCAL_OK;

                if (ifa->ifa_broadcast == ifa1->ifa_broadcast)

                        ok |= BRD_OK;

                if (brd == ifa1->ifa_broadcast)

                        ok |= BRD1_OK;

                if (any == ifa1->ifa_broadcast)

                        ok |= BRD0_OK;

        }

        if (!(ok&BRD_OK))

                fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);

        if (!(ok&BRD1_OK))

                fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);

        if (!(ok&BRD0_OK))

                fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);

        if (!(ok&LOCAL_OK)) {

                fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);

                /* Check, that this local address finally disappeared. */

                if (inet_addr_type(ifa->ifa_local) != RTN_LOCAL) {

                        /* And the last, but not the least thing.

                           We must flush stray FIB entries.

                           First of all, we scan fib_info list searching

                           for stray nexthop entries, then ignite fib_flush.

                        */

                        if (fib_sync_down(ifa->ifa_local, NULL, 0))

                                fib_flush();

                }

        }

#undef LOCAL_OK

#undef BRD_OK

#undef BRD0_OK

#undef BRD1_OK

}

static void fib_disable_ip(struct net_device *dev, int force)

{

        if (fib_sync_down(0, dev, force))

                fib_flush();

        rt_cache_flush(0);

        arp_ifdown(dev);

}

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

{

        struct in_ifaddr *ifa = (struct in_ifaddr*)ptr;

        switch (event) {

        case NETDEV_UP:

                fib_add_ifaddr(ifa);

#ifdef CONFIG_IP_ROUTE_MULTIPATH

                fib_sync_up(ifa->ifa_dev->dev);

#endif

                rt_cache_flush(-1);

                break;

        case NETDEV_DOWN:

                fib_del_ifaddr(ifa);

                if (ifa->ifa_dev && ifa->ifa_dev->ifa_list == NULL) {

                        /* Last address was deleted from this interface.

                           Disable IP.

                         */

                        fib_disable_ip(ifa->ifa_dev->dev, 1);

                } else {

                        rt_cache_flush(-1);

                }

                break;

        }

        return NOTIFY_DONE;

}

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

{

        struct net_device *dev = ptr;

        struct in_device *in_dev = __in_dev_get(dev);

        if (event == NETDEV_UNREGISTER) {

                fib_disable_ip(dev, 2);

                return NOTIFY_DONE;

        }

        if (!in_dev)

                return NOTIFY_DONE;

        switch (event) {

        case NETDEV_UP:

                for_ifa(in_dev) {

                        fib_add_ifaddr(ifa);

                } endfor_ifa(in_dev);

#ifdef CONFIG_IP_ROUTE_MULTIPATH

                fib_sync_up(dev);

#endif

                rt_cache_flush(-1);

                break;

        case NETDEV_DOWN:

                fib_disable_ip(dev, 0);

                break;

        case NETDEV_CHANGEMTU:

        case NETDEV_CHANGE:

                rt_cache_flush(0);

                break;

        }

        return NOTIFY_DONE;

}

struct notifier_block fib_inetaddr_notifier = {

        notifier_call:  fib_inetaddr_event,

};

struct notifier_block fib_netdev_notifier = {

        notifier_call:  fib_netdev_event,

};

void __init ip_fib_init(void)

{

#ifdef CONFIG_PROC_FS

        proc_net_create("route",0,fib_get_procinfo);

#endif          /* CONFIG_PROC_FS */

#ifndef CONFIG_IP_MULTIPLE_TABLES

        local_table = fib_hash_init(RT_TABLE_LOCAL);

        main_table = fib_hash_init(RT_TABLE_MAIN);

#else

        fib_rules_init();

#endif

        register_netdevice_notifier(&fib_netdev_notifier);

        register_inetaddr_notifier(&fib_inetaddr_notifier);

}