dn_dev.c

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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 Device Layer
 *
 * Authors:     Steve Whitehouse <[email protected]>
 *              Eduardo Marcelo Serrat <[email protected]>
 *
 * Changes:
 *          Steve Whitehouse : Devices now see incoming frames so they
 *                             can mark on who it came from.
 *          Steve Whitehouse : Fixed bug in creating neighbours. Each neighbour
 *                             can now have a device specific setup func.
 *          Steve Whitehouse : Added /proc/sys/net/decnet/conf/<dev>/
 *          Steve Whitehouse : Fixed bug which sometimes killed timer
 *          Steve Whitehouse : Multiple ifaddr support
 *          Steve Whitehouse : SIOCGIFCONF is now a compile time option
 *          Steve Whitehouse : /proc/sys/net/decnet/conf/<sys>/forwarding
 *          Steve Whitehouse : Removed timer1 - it's a user space issue now
 *         Patrick Caulfield : Fixed router hello message format
 *          Steve Whitehouse : Got rid of constant sizes for blksize for
 *                             devices. All mtu based now.
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/if_addr.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/skbuff.h>
#include <linux/sysctl.h>
#include <linux/notifier.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <net/net_namespace.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/fib_rules.h>
#include <net/netlink.h>
#include <net/dn.h>
#include <net/dn_dev.h>
#include <net/dn_route.h>
#include <net/dn_neigh.h>
#include <net/dn_fib.h>

#define DN_IFREQ_SIZE (sizeof(struct ifreq) - sizeof(struct sockaddr) + sizeof(struct sockaddr_dn))

static char dn_rt_all_end_mcast[ETH_ALEN] = {0xAB,0x00,0x00,0x04,0x00,0x00};
static char dn_rt_all_rt_mcast[ETH_ALEN]  = {0xAB,0x00,0x00,0x03,0x00,0x00};
static char dn_hiord[ETH_ALEN]            = {0xAA,0x00,0x04,0x00,0x00,0x00};
static unsigned char dn_eco_version[3]    = {0x02,0x00,0x00};

extern struct neigh_table dn_neigh_table;

/*
 * decnet_address is kept in network order.
 */
__le16 decnet_address = 0;

static DEFINE_SPINLOCK(dndev_lock);
static struct net_device *decnet_default_device;
static BLOCKING_NOTIFIER_HEAD(dnaddr_chain);

static struct dn_dev *dn_dev_create(struct net_device *dev, int *err);
static void dn_dev_delete(struct net_device *dev);
static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa);

static int dn_eth_up(struct net_device *);
static void dn_eth_down(struct net_device *);
static void dn_send_brd_hello(struct net_device *dev, struct dn_ifaddr *ifa);
static void dn_send_ptp_hello(struct net_device *dev, struct dn_ifaddr *ifa);

static struct dn_dev_parms dn_dev_list[] =  {
{
    .type =     ARPHRD_ETHER, /* Ethernet */
    .mode =     DN_DEV_BCAST,
    .state =    DN_DEV_S_RU,
    .t2 =       1,
    .t3 =       10,
    .name =     "ethernet",
    .up =       dn_eth_up,
    .down =     dn_eth_down,
    .timer3 =   dn_send_brd_hello,
},
{
    .type =     ARPHRD_IPGRE, /* DECnet tunneled over GRE in IP */
    .mode =     DN_DEV_BCAST,
    .state =    DN_DEV_S_RU,
    .t2 =       1,
    .t3 =       10,
    .name =     "ipgre",
    .timer3 =   dn_send_brd_hello,
},
#if 0
{
    .type =     ARPHRD_X25, /* Bog standard X.25 */
    .mode =     DN_DEV_UCAST,
    .state =    DN_DEV_S_DS,
    .t2 =       1,
    .t3 =       120,
    .name =     "x25",
    .timer3 =   dn_send_ptp_hello,
},
#endif
#if 0
{
    .type =     ARPHRD_PPP, /* DECnet over PPP */
    .mode =     DN_DEV_BCAST,
    .state =    DN_DEV_S_RU,
    .t2 =       1,
    .t3 =       10,
    .name =     "ppp",
    .timer3 =   dn_send_brd_hello,
},
#endif
{
    .type =     ARPHRD_DDCMP, /* DECnet over DDCMP */
    .mode =     DN_DEV_UCAST,
    .state =    DN_DEV_S_DS,
    .t2 =       1,
    .t3 =       120,
    .name =     "ddcmp",
    .timer3 =   dn_send_ptp_hello,
},
{
    .type =     ARPHRD_LOOPBACK, /* Loopback interface - always last */
    .mode =     DN_DEV_BCAST,
    .state =    DN_DEV_S_RU,
    .t2 =       1,
    .t3 =       10,
    .name =     "loopback",
    .timer3 =   dn_send_brd_hello,
}
};

#define DN_DEV_LIST_SIZE ARRAY_SIZE(dn_dev_list)

#define DN_DEV_PARMS_OFFSET(x) offsetof(struct dn_dev_parms, x)

#ifdef CONFIG_SYSCTL

static int min_t2[] = { 1 };
static int max_t2[] = { 60 }; /* No max specified, but this seems sensible */
static int min_t3[] = { 1 };
static int max_t3[] = { 8191 }; /* Must fit in 16 bits when multiplied by BCT3MULT or T3MULT */

static int min_priority[1];
static int max_priority[] = { 127 }; /* From DECnet spec */

static int dn_forwarding_proc(ctl_table *, int,
            void __user *, size_t *, loff_t *);
static struct dn_dev_sysctl_table {
    struct ctl_table_header *sysctl_header;
    ctl_table dn_dev_vars[5];
} dn_dev_sysctl = {
    NULL,
    {
    {
        .procname = "forwarding",
        .data = (void *)DN_DEV_PARMS_OFFSET(forwarding),
        .maxlen = sizeof(int),
        .mode = 0644,
        .proc_handler = dn_forwarding_proc,
    },
    {
        .procname = "priority",
        .data = (void *)DN_DEV_PARMS_OFFSET(priority),
        .maxlen = sizeof(int),
        .mode = 0644,
        .proc_handler = proc_dointvec_minmax,
        .extra1 = &min_priority,
        .extra2 = &max_priority
    },
    {
        .procname = "t2",
        .data = (void *)DN_DEV_PARMS_OFFSET(t2),
        .maxlen = sizeof(int),
        .mode = 0644,
        .proc_handler = proc_dointvec_minmax,
        .extra1 = &min_t2,
        .extra2 = &max_t2
    },
    {
        .procname = "t3",
        .data = (void *)DN_DEV_PARMS_OFFSET(t3),
        .maxlen = sizeof(int),
        .mode = 0644,
        .proc_handler = proc_dointvec_minmax,
        .extra1 = &min_t3,
        .extra2 = &max_t3
    },
    {0}
    },
};

static void dn_dev_sysctl_register(struct net_device *dev, struct dn_dev_parms *parms)
{
    struct dn_dev_sysctl_table *t;
    int i;

    char path[sizeof("net/decnet/conf/") + IFNAMSIZ];

    t = kmemdup(&dn_dev_sysctl, sizeof(*t), GFP_KERNEL);
    if (t == NULL)
        return;

    for(i = 0; i < ARRAY_SIZE(t->dn_dev_vars) - 1; i++) {
        long offset = (long)t->dn_dev_vars[i].data;
        t->dn_dev_vars[i].data = ((char *)parms) + offset;
    }

    snprintf(path, sizeof(path), "net/decnet/conf/%s",
        dev? dev->name : parms->name);

    t->dn_dev_vars[0].extra1 = (void *)dev;

    t->sysctl_header = register_net_sysctl(&init_net, path, t->dn_dev_vars);
    if (t->sysctl_header == NULL)
        kfree(t);
    else
        parms->sysctl = t;
}

static void dn_dev_sysctl_unregister(struct dn_dev_parms *parms)
{
    if (parms->sysctl) {
        struct dn_dev_sysctl_table *t = parms->sysctl;
        parms->sysctl = NULL;
        unregister_net_sysctl_table(t->sysctl_header);
        kfree(t);
    }
}

static int dn_forwarding_proc(ctl_table *table, int write,
                void __user *buffer,
                size_t *lenp, loff_t *ppos)
{
#ifdef CONFIG_DECNET_ROUTER
    struct net_device *dev = table->extra1;
    struct dn_dev *dn_db;
    int err;
    int tmp, old;

    if (table->extra1 == NULL)
        return -EINVAL;

    dn_db = rcu_dereference_raw(dev->dn_ptr);
    old = dn_db->parms.forwarding;

    err = proc_dointvec(table, write, buffer, lenp, ppos);

    if ((err >= 0) && write) {
        if (dn_db->parms.forwarding < 0)
            dn_db->parms.forwarding = 0;
        if (dn_db->parms.forwarding > 2)
            dn_db->parms.forwarding = 2;
        /*
         * What an ugly hack this is... its works, just. It
         * would be nice if sysctl/proc were just that little
         * bit more flexible so I don't have to write a special
         * routine, or suffer hacks like this - SJW
         */
        tmp = dn_db->parms.forwarding;
        dn_db->parms.forwarding = old;
        if (dn_db->parms.down)
            dn_db->parms.down(dev);
        dn_db->parms.forwarding = tmp;
        if (dn_db->parms.up)
            dn_db->parms.up(dev);
    }

    return err;
#else
    return -EINVAL;
#endif
}

#else /* CONFIG_SYSCTL */
static void dn_dev_sysctl_unregister(struct dn_dev_parms *parms)
{
}
static void dn_dev_sysctl_register(struct net_device *dev, struct dn_dev_parms *parms)
{
}

#endif /* CONFIG_SYSCTL */

static inline __u16 mtu2blksize(struct net_device *dev)
{
    u32 blksize = dev->mtu;
    if (blksize > 0xffff)
        blksize = 0xffff;

    if (dev->type == ARPHRD_ETHER ||
        dev->type == ARPHRD_PPP ||
        dev->type == ARPHRD_IPGRE ||
        dev->type == ARPHRD_LOOPBACK)
        blksize -= 2;

    return (__u16)blksize;
}

static struct dn_ifaddr *dn_dev_alloc_ifa(void)
{
    struct dn_ifaddr *ifa;

    ifa = kzalloc(sizeof(*ifa), GFP_KERNEL);

    return ifa;
}

static void dn_dev_free_ifa(struct dn_ifaddr *ifa)
{
    kfree_rcu(ifa, rcu);
}

static void dn_dev_del_ifa(struct dn_dev *dn_db, struct dn_ifaddr __rcu **ifap, int destroy)
{
    struct dn_ifaddr *ifa1 = rtnl_dereference(*ifap);
    unsigned char mac_addr[6];
    struct net_device *dev = dn_db->dev;

    ASSERT_RTNL();

    *ifap = ifa1->ifa_next;

    if (dn_db->dev->type == ARPHRD_ETHER) {
        if (ifa1->ifa_local != dn_eth2dn(dev->dev_addr)) {
            dn_dn2eth(mac_addr, ifa1->ifa_local);
            dev_mc_del(dev, mac_addr);
        }
    }

    dn_ifaddr_notify(RTM_DELADDR, ifa1);
    blocking_notifier_call_chain(&dnaddr_chain, NETDEV_DOWN, ifa1);
    if (destroy) {
        dn_dev_free_ifa(ifa1);

        if (dn_db->ifa_list == NULL)
            dn_dev_delete(dn_db->dev);
    }
}

static int dn_dev_insert_ifa(struct dn_dev *dn_db, struct dn_ifaddr *ifa)
{
    struct net_device *dev = dn_db->dev;
    struct dn_ifaddr *ifa1;
    unsigned char mac_addr[6];

    ASSERT_RTNL();

    /* Check for duplicates */
    for (ifa1 = rtnl_dereference(dn_db->ifa_list);
         ifa1 != NULL;
         ifa1 = rtnl_dereference(ifa1->ifa_next)) {
        if (ifa1->ifa_local == ifa->ifa_local)
            return -EEXIST;
    }

    if (dev->type == ARPHRD_ETHER) {
        if (ifa->ifa_local != dn_eth2dn(dev->dev_addr)) {
            dn_dn2eth(mac_addr, ifa->ifa_local);
            dev_mc_add(dev, mac_addr);
        }
    }

    ifa->ifa_next = dn_db->ifa_list;
    rcu_assign_pointer(dn_db->ifa_list, ifa);

    dn_ifaddr_notify(RTM_NEWADDR, ifa);
    blocking_notifier_call_chain(&dnaddr_chain, NETDEV_UP, ifa);

    return 0;
}

static int dn_dev_set_ifa(struct net_device *dev, struct dn_ifaddr *ifa)
{
    struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
    int rv;

    if (dn_db == NULL) {
        int err;
        dn_db = dn_dev_create(dev, &err);
        if (dn_db == NULL)
            return err;
    }

    ifa->ifa_dev = dn_db;

    if (dev->flags & IFF_LOOPBACK)
        ifa->ifa_scope = RT_SCOPE_HOST;

    rv = dn_dev_insert_ifa(dn_db, ifa);
    if (rv)
        dn_dev_free_ifa(ifa);
    return rv;
}


int dn_dev_ioctl(unsigned int cmd, void __user *arg)
{
    char buffer[DN_IFREQ_SIZE];
    struct ifreq *ifr = (struct ifreq *)buffer;
    struct sockaddr_dn *sdn = (struct sockaddr_dn *)&ifr->ifr_addr;
    struct dn_dev *dn_db;
    struct net_device *dev;
    struct dn_ifaddr *ifa = NULL;
    struct dn_ifaddr __rcu **ifap = NULL;
    int ret = 0;

    if (copy_from_user(ifr, arg, DN_IFREQ_SIZE))
        return -EFAULT;
    ifr->ifr_name[IFNAMSIZ-1] = 0;

    dev_load(&init_net, ifr->ifr_name);

    switch (cmd) {
    case SIOCGIFADDR:
        break;
    case SIOCSIFADDR:
        if (!capable(CAP_NET_ADMIN))
            return -EACCES;
        if (sdn->sdn_family != AF_DECnet)
            return -EINVAL;
        break;
    default:
        return -EINVAL;
    }

    rtnl_lock();

    if ((dev = __dev_get_by_name(&init_net, ifr->ifr_name)) == NULL) {
        ret = -ENODEV;
        goto done;
    }

    if ((dn_db = rtnl_dereference(dev->dn_ptr)) != NULL) {
        for (ifap = &dn_db->ifa_list;
             (ifa = rtnl_dereference(*ifap)) != NULL;
             ifap = &ifa->ifa_next)
            if (strcmp(ifr->ifr_name, ifa->ifa_label) == 0)
                break;
    }

    if (ifa == NULL && cmd != SIOCSIFADDR) {
        ret = -EADDRNOTAVAIL;
        goto done;
    }

    switch (cmd) {
    case SIOCGIFADDR:
        *((__le16 *)sdn->sdn_nodeaddr) = ifa->ifa_local;
        goto rarok;

    case SIOCSIFADDR:
        if (!ifa) {
            if ((ifa = dn_dev_alloc_ifa()) == NULL) {
                ret = -ENOBUFS;
                break;
            }
            memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
        } else {
            if (ifa->ifa_local == dn_saddr2dn(sdn))
                break;
            dn_dev_del_ifa(dn_db, ifap, 0);
        }

        ifa->ifa_local = ifa->ifa_address = dn_saddr2dn(sdn);

        ret = dn_dev_set_ifa(dev, ifa);
    }
done:
    rtnl_unlock();

    return ret;
rarok:
    if (copy_to_user(arg, ifr, DN_IFREQ_SIZE))
        ret = -EFAULT;
    goto done;
}

struct net_device *dn_dev_get_default(void)
{
    struct net_device *dev;

    spin_lock(&dndev_lock);
    dev = decnet_default_device;
    if (dev) {
        if (dev->dn_ptr)
            dev_hold(dev);
        else
            dev = NULL;
    }
    spin_unlock(&dndev_lock);

    return dev;
}

int dn_dev_set_default(struct net_device *dev, int force)
{
    struct net_device *old = NULL;
    int rv = -EBUSY;
    if (!dev->dn_ptr)
        return -ENODEV;

    spin_lock(&dndev_lock);
    if (force || decnet_default_device == NULL) {
        old = decnet_default_device;
        decnet_default_device = dev;
        rv = 0;
    }
    spin_unlock(&dndev_lock);

    if (old)
        dev_put(old);
    return rv;
}

static void dn_dev_check_default(struct net_device *dev)
{
    spin_lock(&dndev_lock);
    if (dev == decnet_default_device) {
        decnet_default_device = NULL;
    } else {
        dev = NULL;
    }
    spin_unlock(&dndev_lock);

    if (dev)
        dev_put(dev);
}

/*
 * Called with RTNL
 */
static struct dn_dev *dn_dev_by_index(int ifindex)
{
    struct net_device *dev;
    struct dn_dev *dn_dev = NULL;

    dev = __dev_get_by_index(&init_net, ifindex);
    if (dev)
        dn_dev = rtnl_dereference(dev->dn_ptr);

    return dn_dev;
}

static const struct nla_policy dn_ifa_policy[IFA_MAX+1] = {
    [IFA_ADDRESS]       = { .type = NLA_U16 },
    [IFA_LOCAL]     = { .type = NLA_U16 },
    [IFA_LABEL]     = { .type = NLA_STRING,
                    .len = IFNAMSIZ - 1 },
};

static int dn_nl_deladdr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
    struct net *net = sock_net(skb->sk);
    struct nlattr *tb[IFA_MAX+1];
    struct dn_dev *dn_db;
    struct ifaddrmsg *ifm;
    struct dn_ifaddr *ifa;
    struct dn_ifaddr __rcu **ifap;
    int err = -EINVAL;

    if (!net_eq(net, &init_net))
        goto errout;

    err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy);
    if (err < 0)
        goto errout;

    err = -ENODEV;
    ifm = nlmsg_data(nlh);
    if ((dn_db = dn_dev_by_index(ifm->ifa_index)) == NULL)
        goto errout;

    err = -EADDRNOTAVAIL;
    for (ifap = &dn_db->ifa_list;
         (ifa = rtnl_dereference(*ifap)) != NULL;
         ifap = &ifa->ifa_next) {
        if (tb[IFA_LOCAL] &&
            nla_memcmp(tb[IFA_LOCAL], &ifa->ifa_local, 2))
            continue;

        if (tb[IFA_LABEL] && nla_strcmp(tb[IFA_LABEL], ifa->ifa_label))
            continue;

        dn_dev_del_ifa(dn_db, ifap, 1);
        return 0;
    }

errout:
    return err;
}

static int dn_nl_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
    struct net *net = sock_net(skb->sk);
    struct nlattr *tb[IFA_MAX+1];
    struct net_device *dev;
    struct dn_dev *dn_db;
    struct ifaddrmsg *ifm;
    struct dn_ifaddr *ifa;
    int err;

    if (!net_eq(net, &init_net))
        return -EINVAL;

    err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, dn_ifa_policy);
    if (err < 0)
        return err;

    if (tb[IFA_LOCAL] == NULL)
        return -EINVAL;

    ifm = nlmsg_data(nlh);
    if ((dev = __dev_get_by_index(&init_net, ifm->ifa_index)) == NULL)
        return -ENODEV;

    if ((dn_db = rtnl_dereference(dev->dn_ptr)) == NULL) {
        dn_db = dn_dev_create(dev, &err);
        if (!dn_db)
            return err;
    }

    if ((ifa = dn_dev_alloc_ifa()) == NULL)
        return -ENOBUFS;

    if (tb[IFA_ADDRESS] == NULL)
        tb[IFA_ADDRESS] = tb[IFA_LOCAL];

    ifa->ifa_local = nla_get_le16(tb[IFA_LOCAL]);
    ifa->ifa_address = nla_get_le16(tb[IFA_ADDRESS]);
    ifa->ifa_flags = ifm->ifa_flags;
    ifa->ifa_scope = ifm->ifa_scope;
    ifa->ifa_dev = dn_db;

    if (tb[IFA_LABEL])
        nla_strlcpy(ifa->ifa_label, tb[IFA_LABEL], IFNAMSIZ);
    else
        memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);

    err = dn_dev_insert_ifa(dn_db, ifa);
    if (err)
        dn_dev_free_ifa(ifa);

    return err;
}

static inline size_t dn_ifaddr_nlmsg_size(void)
{
    return NLMSG_ALIGN(sizeof(struct ifaddrmsg))
           + nla_total_size(IFNAMSIZ) /* IFA_LABEL */
           + nla_total_size(2) /* IFA_ADDRESS */
           + nla_total_size(2); /* IFA_LOCAL */
}

static int dn_nl_fill_ifaddr(struct sk_buff *skb, struct dn_ifaddr *ifa,
                 u32 portid, u32 seq, int event, unsigned int flags)
{
    struct ifaddrmsg *ifm;
    struct nlmsghdr *nlh;

    nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), flags);
    if (nlh == NULL)
        return -EMSGSIZE;

    ifm = nlmsg_data(nlh);
    ifm->ifa_family = AF_DECnet;
    ifm->ifa_prefixlen = 16;
    ifm->ifa_flags = ifa->ifa_flags | IFA_F_PERMANENT;
    ifm->ifa_scope = ifa->ifa_scope;
    ifm->ifa_index = ifa->ifa_dev->dev->ifindex;

    if ((ifa->ifa_address &&
         nla_put_le16(skb, IFA_ADDRESS, ifa->ifa_address)) ||
        (ifa->ifa_local &&
         nla_put_le16(skb, IFA_LOCAL, ifa->ifa_local)) ||
        (ifa->ifa_label[0] &&
         nla_put_string(skb, IFA_LABEL, ifa->ifa_label)))
        goto nla_put_failure;
    return nlmsg_end(skb, nlh);

nla_put_failure:
    nlmsg_cancel(skb, nlh);
    return -EMSGSIZE;
}

static void dn_ifaddr_notify(int event, struct dn_ifaddr *ifa)
{
    struct sk_buff *skb;
    int err = -ENOBUFS;

    skb = alloc_skb(dn_ifaddr_nlmsg_size(), GFP_KERNEL);
    if (skb == NULL)
        goto errout;

    err = dn_nl_fill_ifaddr(skb, ifa, 0, 0, event, 0);
    if (err < 0) {
        /* -EMSGSIZE implies BUG in dn_ifaddr_nlmsg_size() */
        WARN_ON(err == -EMSGSIZE);
        kfree_skb(skb);
        goto errout;
    }
    rtnl_notify(skb, &init_net, 0, RTNLGRP_DECnet_IFADDR, NULL, GFP_KERNEL);
    return;
errout:
    if (err < 0)
        rtnl_set_sk_err(&init_net, RTNLGRP_DECnet_IFADDR, err);
}

static int dn_nl_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)
{
    struct net *net = sock_net(skb->sk);
    int idx, dn_idx = 0, skip_ndevs, skip_naddr;
    struct net_device *dev;
    struct dn_dev *dn_db;
    struct dn_ifaddr *ifa;

    if (!net_eq(net, &init_net))
        return 0;

    skip_ndevs = cb->args[0];
    skip_naddr = cb->args[1];

    idx = 0;
    rcu_read_lock();
    for_each_netdev_rcu(&init_net, dev) {
        if (idx < skip_ndevs)
            goto cont;
        else if (idx > skip_ndevs) {
            /* Only skip over addresses for first dev dumped
             * in this iteration (idx == skip_ndevs) */
            skip_naddr = 0;
        }

        if ((dn_db = rcu_dereference(dev->dn_ptr)) == NULL)
            goto cont;

        for (ifa = rcu_dereference(dn_db->ifa_list), dn_idx = 0; ifa;
             ifa = rcu_dereference(ifa->ifa_next), dn_idx++) {
            if (dn_idx < skip_naddr)
                continue;

            if (dn_nl_fill_ifaddr(skb, ifa, NETLINK_CB(cb->skb).portid,
                          cb->nlh->nlmsg_seq, RTM_NEWADDR,
                          NLM_F_MULTI) < 0)
                goto done;
        }
cont:
        idx++;
    }
done:
    rcu_read_unlock();
    cb->args[0] = idx;
    cb->args[1] = dn_idx;

    return skb->len;
}

static int dn_dev_get_first(struct net_device *dev, __le16 *addr)
{
    struct dn_dev *dn_db;
    struct dn_ifaddr *ifa;
    int rv = -ENODEV;

    rcu_read_lock();
    dn_db = rcu_dereference(dev->dn_ptr);
    if (dn_db == NULL)
        goto out;

    ifa = rcu_dereference(dn_db->ifa_list);
    if (ifa != NULL) {
        *addr = ifa->ifa_local;
        rv = 0;
    }
out:
    rcu_read_unlock();
    return rv;
}

/*
 * Find a default address to bind to.
 *
 * This is one of those areas where the initial VMS concepts don't really
 * map onto the Linux concepts, and since we introduced multiple addresses
 * per interface we have to cope with slightly odd ways of finding out what
 * "our address" really is. Mostly it's not a problem; for this we just guess
 * a sensible default. Eventually the routing code will take care of all the
 * nasties for us I hope.
 */
int dn_dev_bind_default(__le16 *addr)
{
    struct net_device *dev;
    int rv;
    dev = dn_dev_get_default();
last_chance:
    if (dev) {
        rv = dn_dev_get_first(dev, addr);
        dev_put(dev);
        if (rv == 0 || dev == init_net.loopback_dev)
            return rv;
    }
    dev = init_net.loopback_dev;
    dev_hold(dev);
    goto last_chance;
}

static void dn_send_endnode_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
    struct endnode_hello_message *msg;
    struct sk_buff *skb = NULL;
    __le16 *pktlen;
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);

    if ((skb = dn_alloc_skb(NULL, sizeof(*msg), GFP_ATOMIC)) == NULL)
        return;

    skb->dev = dev;

    msg = (struct endnode_hello_message *)skb_put(skb,sizeof(*msg));

    msg->msgflg  = 0x0D;
    memcpy(msg->tiver, dn_eco_version, 3);
    dn_dn2eth(msg->id, ifa->ifa_local);
    msg->iinfo   = DN_RT_INFO_ENDN;
    msg->blksize = cpu_to_le16(mtu2blksize(dev));
    msg->area    = 0x00;
    memset(msg->seed, 0, 8);
    memcpy(msg->neighbor, dn_hiord, ETH_ALEN);

    if (dn_db->router) {
        struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
        dn_dn2eth(msg->neighbor, dn->addr);
    }

    msg->timer   = cpu_to_le16((unsigned short)dn_db->parms.t3);
    msg->mpd     = 0x00;
    msg->datalen = 0x02;
    memset(msg->data, 0xAA, 2);

    pktlen = (__le16 *)skb_push(skb,2);
    *pktlen = cpu_to_le16(skb->len - 2);

    skb_reset_network_header(skb);

    dn_rt_finish_output(skb, dn_rt_all_rt_mcast, msg->id);
}


#define DRDELAY (5 * HZ)

static int dn_am_i_a_router(struct dn_neigh *dn, struct dn_dev *dn_db, struct dn_ifaddr *ifa)
{
    /* First check time since device went up */
    if ((jiffies - dn_db->uptime) < DRDELAY)
        return 0;

    /* If there is no router, then yes... */
    if (!dn_db->router)
        return 1;

    /* otherwise only if we have a higher priority or.. */
    if (dn->priority < dn_db->parms.priority)
        return 1;

    /* if we have equal priority and a higher node number */
    if (dn->priority != dn_db->parms.priority)
        return 0;

    if (le16_to_cpu(dn->addr) < le16_to_cpu(ifa->ifa_local))
        return 1;

    return 0;
}

static void dn_send_router_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
    int n;
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);
    struct dn_neigh *dn = (struct dn_neigh *)dn_db->router;
    struct sk_buff *skb;
    size_t size;
    unsigned char *ptr;
    unsigned char *i1, *i2;
    __le16 *pktlen;
    char *src;

    if (mtu2blksize(dev) < (26 + 7))
        return;

    n = mtu2blksize(dev) - 26;
    n /= 7;

    if (n > 32)
        n = 32;

    size = 2 + 26 + 7 * n;

    if ((skb = dn_alloc_skb(NULL, size, GFP_ATOMIC)) == NULL)
        return;

    skb->dev = dev;
    ptr = skb_put(skb, size);

    *ptr++ = DN_RT_PKT_CNTL | DN_RT_PKT_ERTH;
    *ptr++ = 2; /* ECO */
    *ptr++ = 0;
    *ptr++ = 0;
    dn_dn2eth(ptr, ifa->ifa_local);
    src = ptr;
    ptr += ETH_ALEN;
    *ptr++ = dn_db->parms.forwarding == 1 ?
            DN_RT_INFO_L1RT : DN_RT_INFO_L2RT;
    *((__le16 *)ptr) = cpu_to_le16(mtu2blksize(dev));
    ptr += 2;
    *ptr++ = dn_db->parms.priority; /* Priority */
    *ptr++ = 0; /* Area: Reserved */
    *((__le16 *)ptr) = cpu_to_le16((unsigned short)dn_db->parms.t3);
    ptr += 2;
    *ptr++ = 0; /* MPD: Reserved */
    i1 = ptr++;
    memset(ptr, 0, 7); /* Name: Reserved */
    ptr += 7;
    i2 = ptr++;

    n = dn_neigh_elist(dev, ptr, n);

    *i2 = 7 * n;
    *i1 = 8 + *i2;

    skb_trim(skb, (27 + *i2));

    pktlen = (__le16 *)skb_push(skb, 2);
    *pktlen = cpu_to_le16(skb->len - 2);

    skb_reset_network_header(skb);

    if (dn_am_i_a_router(dn, dn_db, ifa)) {
        struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
        if (skb2) {
            dn_rt_finish_output(skb2, dn_rt_all_end_mcast, src);
        }
    }

    dn_rt_finish_output(skb, dn_rt_all_rt_mcast, src);
}

static void dn_send_brd_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);

    if (dn_db->parms.forwarding == 0)
        dn_send_endnode_hello(dev, ifa);
    else
        dn_send_router_hello(dev, ifa);
}

static void dn_send_ptp_hello(struct net_device *dev, struct dn_ifaddr *ifa)
{
    int tdlen = 16;
    int size = dev->hard_header_len + 2 + 4 + tdlen;
    struct sk_buff *skb = dn_alloc_skb(NULL, size, GFP_ATOMIC);
    int i;
    unsigned char *ptr;
    char src[ETH_ALEN];

    if (skb == NULL)
        return ;

    skb->dev = dev;
    skb_push(skb, dev->hard_header_len);
    ptr = skb_put(skb, 2 + 4 + tdlen);

    *ptr++ = DN_RT_PKT_HELO;
    *((__le16 *)ptr) = ifa->ifa_local;
    ptr += 2;
    *ptr++ = tdlen;

    for(i = 0; i < tdlen; i++)
        *ptr++ = 0252;

    dn_dn2eth(src, ifa->ifa_local);
    dn_rt_finish_output(skb, dn_rt_all_rt_mcast, src);
}

static int dn_eth_up(struct net_device *dev)
{
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);

    if (dn_db->parms.forwarding == 0)
        dev_mc_add(dev, dn_rt_all_end_mcast);
    else
        dev_mc_add(dev, dn_rt_all_rt_mcast);

    dn_db->use_long = 1;

    return 0;
}

static void dn_eth_down(struct net_device *dev)
{
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);

    if (dn_db->parms.forwarding == 0)
        dev_mc_del(dev, dn_rt_all_end_mcast);
    else
        dev_mc_del(dev, dn_rt_all_rt_mcast);
}

static void dn_dev_set_timer(struct net_device *dev);

static void dn_dev_timer_func(unsigned long arg)
{
    struct net_device *dev = (struct net_device *)arg;
    struct dn_dev *dn_db;
    struct dn_ifaddr *ifa;

    rcu_read_lock();
    dn_db = rcu_dereference(dev->dn_ptr);
    if (dn_db->t3 <= dn_db->parms.t2) {
        if (dn_db->parms.timer3) {
            for (ifa = rcu_dereference(dn_db->ifa_list);
                 ifa;
                 ifa = rcu_dereference(ifa->ifa_next)) {
                if (!(ifa->ifa_flags & IFA_F_SECONDARY))
                    dn_db->parms.timer3(dev, ifa);
            }
        }
        dn_db->t3 = dn_db->parms.t3;
    } else {
        dn_db->t3 -= dn_db->parms.t2;
    }
    rcu_read_unlock();
    dn_dev_set_timer(dev);
}

static void dn_dev_set_timer(struct net_device *dev)
{
    struct dn_dev *dn_db = rcu_dereference_raw(dev->dn_ptr);

    if (dn_db->parms.t2 > dn_db->parms.t3)
        dn_db->parms.t2 = dn_db->parms.t3;

    dn_db->timer.data = (unsigned long)dev;
    dn_db->timer.function = dn_dev_timer_func;
    dn_db->timer.expires = jiffies + (dn_db->parms.t2 * HZ);

    add_timer(&dn_db->timer);
}

static struct dn_dev *dn_dev_create(struct net_device *dev, int *err)
{
    int i;
    struct dn_dev_parms *p = dn_dev_list;
    struct dn_dev *dn_db;

    for(i = 0; i < DN_DEV_LIST_SIZE; i++, p++) {
        if (p->type == dev->type)
            break;
    }

    *err = -ENODEV;
    if (i == DN_DEV_LIST_SIZE)
        return NULL;

    *err = -ENOBUFS;
    if ((dn_db = kzalloc(sizeof(struct dn_dev), GFP_ATOMIC)) == NULL)
        return NULL;

    memcpy(&dn_db->parms, p, sizeof(struct dn_dev_parms));

    rcu_assign_pointer(dev->dn_ptr, dn_db);
    dn_db->dev = dev;
    init_timer(&dn_db->timer);

    dn_db->uptime = jiffies;

    dn_db->neigh_parms = neigh_parms_alloc(dev, &dn_neigh_table);
    if (!dn_db->neigh_parms) {
        RCU_INIT_POINTER(dev->dn_ptr, NULL);
        kfree(dn_db);
        return NULL;
    }

    if (dn_db->parms.up) {
        if (dn_db->parms.up(dev) < 0) {
            neigh_parms_release(&dn_neigh_table, dn_db->neigh_parms);
            dev->dn_ptr = NULL;
            kfree(dn_db);
            return NULL;
        }
    }

    dn_dev_sysctl_register(dev, &dn_db->parms);

    dn_dev_set_timer(dev);

    *err = 0;
    return dn_db;
}


/*
 * This processes a device up event. We only start up
 * the loopback device & ethernet devices with correct
 * MAC addresses automatically. Others must be started
 * specifically.
 *
 * FIXME: How should we configure the loopback address ? If we could dispense
 * with using decnet_address here and for autobind, it will be one less thing
 * for users to worry about setting up.
 */

void dn_dev_up(struct net_device *dev)
{
    struct dn_ifaddr *ifa;
    __le16 addr = decnet_address;
    int maybe_default = 0;
    struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);

    if ((dev->type != ARPHRD_ETHER) && (dev->type != ARPHRD_LOOPBACK))
        return;

    /*
     * Need to ensure that loopback device has a dn_db attached to it
     * to allow creation of neighbours against it, even though it might
     * not have a local address of its own. Might as well do the same for
     * all autoconfigured interfaces.
     */
    if (dn_db == NULL) {
        int err;
        dn_db = dn_dev_create(dev, &err);
        if (dn_db == NULL)
            return;
    }

    if (dev->type == ARPHRD_ETHER) {
        if (memcmp(dev->dev_addr, dn_hiord, 4) != 0)
            return;
        addr = dn_eth2dn(dev->dev_addr);
        maybe_default = 1;
    }

    if (addr == 0)
        return;

    if ((ifa = dn_dev_alloc_ifa()) == NULL)
        return;

    ifa->ifa_local = ifa->ifa_address = addr;
    ifa->ifa_flags = 0;
    ifa->ifa_scope = RT_SCOPE_UNIVERSE;
    strcpy(ifa->ifa_label, dev->name);

    dn_dev_set_ifa(dev, ifa);

    /*
     * Automagically set the default device to the first automatically
     * configured ethernet card in the system.
     */
    if (maybe_default) {
        dev_hold(dev);
        if (dn_dev_set_default(dev, 0))
            dev_put(dev);
    }
}

static void dn_dev_delete(struct net_device *dev)
{
    struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);

    if (dn_db == NULL)
        return;

    del_timer_sync(&dn_db->timer);
    dn_dev_sysctl_unregister(&dn_db->parms);
    dn_dev_check_default(dev);
    neigh_ifdown(&dn_neigh_table, dev);

    if (dn_db->parms.down)
        dn_db->parms.down(dev);

    dev->dn_ptr = NULL;

    neigh_parms_release(&dn_neigh_table, dn_db->neigh_parms);
    neigh_ifdown(&dn_neigh_table, dev);

    if (dn_db->router)
        neigh_release(dn_db->router);
    if (dn_db->peer)
        neigh_release(dn_db->peer);

    kfree(dn_db);
}

void dn_dev_down(struct net_device *dev)
{
    struct dn_dev *dn_db = rtnl_dereference(dev->dn_ptr);
    struct dn_ifaddr *ifa;

    if (dn_db == NULL)
        return;

    while ((ifa = rtnl_dereference(dn_db->ifa_list)) != NULL) {
        dn_dev_del_ifa(dn_db, &dn_db->ifa_list, 0);
        dn_dev_free_ifa(ifa);
    }

    dn_dev_delete(dev);
}

void dn_dev_init_pkt(struct sk_buff *skb)
{
}

void dn_dev_veri_pkt(struct sk_buff *skb)
{
}

void dn_dev_hello(struct sk_buff *skb)
{
}

void dn_dev_devices_off(void)
{
    struct net_device *dev;

    rtnl_lock();
    for_each_netdev(&init_net, dev)
        dn_dev_down(dev);
    rtnl_unlock();

}

void dn_dev_devices_on(void)
{
    struct net_device *dev;

    rtnl_lock();
    for_each_netdev(&init_net, dev) {
        if (dev->flags & IFF_UP)
            dn_dev_up(dev);
    }
    rtnl_unlock();
}

int register_dnaddr_notifier(struct notifier_block *nb)
{
    return blocking_notifier_chain_register(&dnaddr_chain, nb);
}

int unregister_dnaddr_notifier(struct notifier_block *nb)
{
    return blocking_notifier_chain_unregister(&dnaddr_chain, nb);
}

#ifdef CONFIG_PROC_FS
static inline int is_dn_dev(struct net_device *dev)
{
    return dev->dn_ptr != NULL;
}

static void *dn_dev_seq_start(struct seq_file *seq, loff_t *pos)
    __acquires(RCU)
{
    int i;
    struct net_device *dev;

    rcu_read_lock();

    if (*pos == 0)
        return SEQ_START_TOKEN;

    i = 1;
    for_each_netdev_rcu(&init_net, dev) {
        if (!is_dn_dev(dev))
            continue;

        if (i++ == *pos)
            return dev;
    }

    return NULL;
}

static void *dn_dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
    struct net_device *dev;

    ++*pos;

    dev = v;
    if (v == SEQ_START_TOKEN)
        dev = net_device_entry(&init_net.dev_base_head);

    for_each_netdev_continue_rcu(&init_net, dev) {
        if (!is_dn_dev(dev))
            continue;

        return dev;
    }

    return NULL;
}

static void dn_dev_seq_stop(struct seq_file *seq, void *v)
    __releases(RCU)
{
    rcu_read_unlock();
}

static char *dn_type2asc(char type)
{
    switch (type) {
    case DN_DEV_BCAST:
        return "B";
    case DN_DEV_UCAST:
        return "U";
    case DN_DEV_MPOINT:
        return "M";
    }

    return "?";
}

static int dn_dev_seq_show(struct seq_file *seq, void *v)
{
    if (v == SEQ_START_TOKEN)
        seq_puts(seq, "Name     Flags T1   Timer1 T3   Timer3 BlkSize Pri State DevType    Router Peer\n");
    else {
        struct net_device *dev = v;
        char peer_buf[DN_ASCBUF_LEN];
        char router_buf[DN_ASCBUF_LEN];
        struct dn_dev *dn_db = rcu_dereference(dev->dn_ptr);

        seq_printf(seq, "%-8s %1s     %04u %04u   %04lu %04lu"
                "   %04hu    %03d %02x    %-10s %-7s %-7s\n",
                dev->name ? dev->name : "???",
                dn_type2asc(dn_db->parms.mode),
                0, 0,
                dn_db->t3, dn_db->parms.t3,
                mtu2blksize(dev),
                dn_db->parms.priority,
                dn_db->parms.state, dn_db->parms.name,
                dn_db->router ? dn_addr2asc(le16_to_cpu(*(__le16 *)dn_db->router->primary_key), router_buf) : "",
                dn_db->peer ? dn_addr2asc(le16_to_cpu(*(__le16 *)dn_db->peer->primary_key), peer_buf) : "");
    }
    return 0;
}

static const struct seq_operations dn_dev_seq_ops = {
    .start  = dn_dev_seq_start,
    .next   = dn_dev_seq_next,
    .stop   = dn_dev_seq_stop,
    .show   = dn_dev_seq_show,
};

static int dn_dev_seq_open(struct inode *inode, struct file *file)
{
    return seq_open(file, &dn_dev_seq_ops);
}

static const struct file_operations dn_dev_seq_fops = {
    .owner   = THIS_MODULE,
    .open    = dn_dev_seq_open,
    .read    = seq_read,
    .llseek  = seq_lseek,
    .release = seq_release,
};

#endif /* CONFIG_PROC_FS */

static int addr[2];
module_param_array(addr, int, NULL, 0444);
MODULE_PARM_DESC(addr, "The DECnet address of this machine: area,node");

void __init dn_dev_init(void)
{
    if (addr[0] > 63 || addr[0] < 0) {
        printk(KERN_ERR "DECnet: Area must be between 0 and 63");
        return;
    }

    if (addr[1] > 1023 || addr[1] < 0) {
        printk(KERN_ERR "DECnet: Node must be between 0 and 1023");
        return;
    }

    decnet_address = cpu_to_le16((addr[0] << 10) | addr[1]);

    dn_dev_devices_on();

    rtnl_register(PF_DECnet, RTM_NEWADDR, dn_nl_newaddr, NULL, NULL);
    rtnl_register(PF_DECnet, RTM_DELADDR, dn_nl_deladdr, NULL, NULL);
    rtnl_register(PF_DECnet, RTM_GETADDR, NULL, dn_nl_dump_ifaddr, NULL);

    proc_net_fops_create(&init_net, "decnet_dev", S_IRUGO, &dn_dev_seq_fops);

#ifdef CONFIG_SYSCTL
    {
        int i;
        for(i = 0; i < DN_DEV_LIST_SIZE; i++)
            dn_dev_sysctl_register(NULL, &dn_dev_list[i]);
    }
#endif /* CONFIG_SYSCTL */
}

void __exit dn_dev_cleanup(void)
{
#ifdef CONFIG_SYSCTL
    {
        int i;
        for(i = 0; i < DN_DEV_LIST_SIZE; i++)
            dn_dev_sysctl_unregister(&dn_dev_list[i]);
    }
#endif /* CONFIG_SYSCTL */

    proc_net_remove(&init_net, "decnet_dev");

    dn_dev_devices_off();
}