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/*

 * DECnet       An implementation of the DECnet protocol suite for the LINUX

 *              operating system.  DECnet is implemented using the  BSD Socket

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

 *

 *              DECnet Routing Forwarding Information Base (Rules)

 *

 * Author:      Steve Whitehouse <SteveW@ACM.org>

 *              Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c

 *

 *

 * Changes:

 *

 */

#include <linux/config.h>

#include <linux/string.h>

#include <linux/net.h>

#include <linux/socket.h>

#include <linux/sockios.h>

#include <linux/init.h>

#include <linux/skbuff.h>

#include <linux/netlink.h>

#include <linux/rtnetlink.h>

#include <linux/proc_fs.h>

#include <linux/netdevice.h>

#include <linux/timer.h>

#include <linux/spinlock.h>

#include <asm/atomic.h>

#include <asm/uaccess.h>

#include <net/neighbour.h>

#include <net/dst.h>

#include <net/dn.h>

#include <net/dn_fib.h>

#include <net/dn_neigh.h>

#include <net/dn_dev.h>

struct dn_fib_rule

{

        struct dn_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;

        dn_address              r_src;

        dn_address              r_srcmask;

        dn_address              r_dst;

        dn_address              r_dstmask;

        u8                      r_flags;

#ifdef CONFIG_DECNET_ROUTE_FWMARK

        u32                     r_fwmark;

#endif

        int                     r_ifindex;

        char                    r_ifname[IFNAMSIZ];

        int                     r_dead;

};

static struct dn_fib_rule default_rule = {

        r_clntref:              ATOMIC_INIT(2),

        r_preference:           0x7fff,

        r_table:                DN_DEFAULT_TABLE,

        r_action:               RTN_UNICAST

};

static struct dn_fib_rule *dn_fib_rules = &default_rule;

static rwlock_t dn_fib_rules_lock = RW_LOCK_UNLOCKED;

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

{

        struct rtattr **rta = arg;

        struct rtmsg *rtm = NLMSG_DATA(nlh);

        struct dn_fib_rule *r, **rp;

        int err = -ESRCH;

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

                if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 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, 2) == 0) &&

#ifdef CONFIG_DECNET_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 == &default_rule)

                                break;

                        write_lock_bh(&dn_fib_rules_lock);

                        *rp = r->r_next;

                        r->r_dead = 1;

                        write_unlock_bh(&dn_fib_rules_lock);

                        dn_fib_rule_put(r);

                        err = 0;

                        break;

                }

        }

        return err;

}

void dn_fib_rule_put(struct dn_fib_rule *r)

{

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

                if (r->r_dead)

                        kfree(r);

                else

                        printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");

        }

}

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

{

        struct rtattr **rta = arg;

        struct rtmsg *rtm = NLMSG_DATA(nlh);

        struct dn_fib_rule *r, *new_r, **rp;

        unsigned char table_id;

        if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)

                return -EINVAL;

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

                return -EINVAL;

        if (rtm->rtm_type == RTN_NAT)

                return -EINVAL;

        table_id = rtm->rtm_table;

        if (table_id == RT_TABLE_UNSPEC) {

                struct dn_fib_table *tb;

                if (rtm->rtm_type == RTN_UNICAST) {

                        if ((tb = dn_fib_empty_table()) == NULL)

                                return -ENOBUFS;

                        table_id = tb->n;

                }

        }

        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]), 2);

        if (rta[RTA_DST-1])

                memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);

        new_r->r_src_len = rtm->rtm_src_len;

        new_r->r_dst_len = rtm->rtm_dst_len;

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

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

#ifdef CONFIG_DECNET_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;

        }

        rp = &dn_fib_rules;

        if (!new_r->r_preference) {

                r = dn_fib_rules;

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

                        rp = &dn_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(&dn_fib_rules_lock);

        *rp = new_r;

        write_unlock_bh(&dn_fib_rules_lock);

        return 0;

}

int dn_fib_lookup(struct dn_fib_key *key, struct dn_fib_res *res)

{

        struct dn_fib_rule *r, *policy;

        struct dn_fib_table *tb;

        dn_address saddr = key->src;

        dn_address daddr = key->dst;

        int err;

        read_lock(&dn_fib_rules_lock);

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

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

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

#ifdef CONFIG_DECNET_ROUTE_FWMARK

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

#endif

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

                        continue;

                switch(r->r_action) {

                        case RTN_UNICAST:

                                policy = r;

                                break;

                        case RTN_UNREACHABLE:

                                read_unlock(&dn_fib_rules_lock);

                                return -ENETUNREACH;

                        default:

                        case RTN_BLACKHOLE:

                                read_unlock(&dn_fib_rules_lock);

                                return -EINVAL;

                        case RTN_PROHIBIT:

                                read_unlock(&dn_fib_rules_lock);

                                return -EACCES;

                }

                if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)

                        continue;

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

                if (err == 0) {

                        res->r = policy;

                        if (policy)

                                atomic_inc(&policy->r_clntref);

                        read_unlock(&dn_fib_rules_lock);

                        return 0;

                }

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

                        read_unlock(&dn_fib_rules_lock);

                        return err;

                }

        }

        read_unlock(&dn_fib_rules_lock);

        return -ESRCH;

}

static void dn_fib_rules_detach(struct net_device *dev)

{

        struct dn_fib_rule *r;

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

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

                        write_lock_bh(&dn_fib_rules_lock);

                        r->r_ifindex = -1;

                        write_unlock_bh(&dn_fib_rules_lock);

                }

        }

}

static void dn_fib_rules_attach(struct net_device *dev)

{

        struct dn_fib_rule *r;

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

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

                        write_lock_bh(&dn_fib_rules_lock);

                        r->r_ifindex = dev->ifindex;

                        write_unlock_bh(&dn_fib_rules_lock);

                }

        }

}

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

{

        struct net_device *dev = ptr;

        switch(event) {

                case NETDEV_UNREGISTER:

                        dn_fib_rules_detach(dev);

                        dn_fib_sync_down(0, dev, 1);

                case NETDEV_REGISTER:

                        dn_fib_rules_attach(dev);

                        dn_fib_sync_up(dev);

        }

        return NOTIFY_DONE;

}

static struct notifier_block dn_fib_rules_notifier = {

        notifier_call:          dn_fib_rules_event,

};

static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_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_DECnet;

        rtm->rtm_dst_len = r->r_dst_len;

        rtm->rtm_src_len = r->r_src_len;

        rtm->rtm_tos = 0;

#ifdef CONFIG_DECNET_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, 2, &r->r_dst);

        if (r->r_src_len)

                RTA_PUT(skb, RTA_SRC, 2, &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);

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

        return skb->len;

nlmsg_failure:

rtattr_failure:

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

        return -1;

}

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

{

        int idx;

        int s_idx = cb->args[0];

        struct dn_fib_rule *r;

        read_lock(&dn_fib_rules_lock);

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

                if (idx < s_idx)

                        continue;

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

                        break;

        }

        read_unlock(&dn_fib_rules_lock);

        cb->args[0] = idx;

        return skb->len;

}

void __init dn_fib_rules_init(void)

{

        register_netdevice_notifier(&dn_fib_rules_notifier);

}

void __exit dn_fib_rules_cleanup(void)

{

        unregister_netdevice_notifier(&dn_fib_rules_notifier);

}