rtnetlink.c

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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.
 *
 *              Routing netlink socket interface: protocol independent part.
 *
 * 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:
 *      Vitaly E. Lavrov                RTA_OK arithmetics was wrong.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/capability.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/if_addr.h>
#include <linux/nsproxy.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/string.h>

#include <linux/inet.h>
#include <linux/netdevice.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/arp.h>
#include <net/route.h>
#include <net/udp.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/fib_rules.h>
#include <net/rtnetlink.h>

struct rtnl_link
{
        rtnl_doit_func          doit;
        rtnl_dumpit_func        dumpit;
};

static DEFINE_MUTEX(rtnl_mutex);

void rtnl_lock(void)
{
        mutex_lock(&rtnl_mutex);
}

void __rtnl_unlock(void)
{
        mutex_unlock(&rtnl_mutex);
}

void rtnl_unlock(void)
{
        /* This fellow will unlock it for us. */
        netdev_run_todo();
}

int rtnl_trylock(void)
{
        return mutex_trylock(&rtnl_mutex);
}

int rtnl_is_locked(void)
{
        return mutex_is_locked(&rtnl_mutex);
}

static struct rtnl_link *rtnl_msg_handlers[NPROTO];

static inline int rtm_msgindex(int msgtype)
{
        int msgindex = msgtype - RTM_BASE;

        /*
         * msgindex < 0 implies someone tried to register a netlink
         * control code. msgindex >= RTM_NR_MSGTYPES may indicate that
         * the message type has not been added to linux/rtnetlink.h
         */
        BUG_ON(msgindex < 0 || msgindex >= RTM_NR_MSGTYPES);

        return msgindex;
}

static rtnl_doit_func rtnl_get_doit(int protocol, int msgindex)
{
        struct rtnl_link *tab;

        tab = rtnl_msg_handlers[protocol];
        if (tab == NULL || tab[msgindex].doit == NULL)
                tab = rtnl_msg_handlers[PF_UNSPEC];

        return tab ? tab[msgindex].doit : NULL;
}

static rtnl_dumpit_func rtnl_get_dumpit(int protocol, int msgindex)
{
        struct rtnl_link *tab;

        tab = rtnl_msg_handlers[protocol];
        if (tab == NULL || tab[msgindex].dumpit == NULL)
                tab = rtnl_msg_handlers[PF_UNSPEC];

        return tab ? tab[msgindex].dumpit : NULL;
}

/**
 * __rtnl_register - Register a rtnetlink message type
 * @protocol: Protocol family or PF_UNSPEC
 * @msgtype: rtnetlink message type
 * @doit: Function pointer called for each request message
 * @dumpit: Function pointer called for each dump request (NLM_F_DUMP) message
 *
 * Registers the specified function pointers (at least one of them has
 * to be non-NULL) to be called whenever a request message for the
 * specified protocol family and message type is received.
 *
 * The special protocol family PF_UNSPEC may be used to define fallback
 * function pointers for the case when no entry for the specific protocol
 * family exists.
 *
 * Returns 0 on success or a negative error code.
 */
int __rtnl_register(int protocol, int msgtype,
                    rtnl_doit_func doit, rtnl_dumpit_func dumpit)
{
        struct rtnl_link *tab;
        int msgindex;

        BUG_ON(protocol < 0 || protocol >= NPROTO);
        msgindex = rtm_msgindex(msgtype);

        tab = rtnl_msg_handlers[protocol];
        if (tab == NULL) {
                tab = kcalloc(RTM_NR_MSGTYPES, sizeof(*tab), GFP_KERNEL);
                if (tab == NULL)
                        return -ENOBUFS;

                rtnl_msg_handlers[protocol] = tab;
        }

        if (doit)
                tab[msgindex].doit = doit;

        if (dumpit)
                tab[msgindex].dumpit = dumpit;

        return 0;
}

EXPORT_SYMBOL_GPL(__rtnl_register);

/**
 * rtnl_register - Register a rtnetlink message type
 *
 * Identical to __rtnl_register() but panics on failure. This is useful
 * as failure of this function is very unlikely, it can only happen due
 * to lack of memory when allocating the chain to store all message
 * handlers for a protocol. Meant for use in init functions where lack
 * of memory implies no sense in continueing.
 */
void rtnl_register(int protocol, int msgtype,
                   rtnl_doit_func doit, rtnl_dumpit_func dumpit)
{
        if (__rtnl_register(protocol, msgtype, doit, dumpit) < 0)
                panic("Unable to register rtnetlink message handler, "
                      "protocol = %d, message type = %d\n",
                      protocol, msgtype);
}

EXPORT_SYMBOL_GPL(rtnl_register);

/**
 * rtnl_unregister - Unregister a rtnetlink message type
 * @protocol: Protocol family or PF_UNSPEC
 * @msgtype: rtnetlink message type
 *
 * Returns 0 on success or a negative error code.
 */
int rtnl_unregister(int protocol, int msgtype)
{
        int msgindex;

        BUG_ON(protocol < 0 || protocol >= NPROTO);
        msgindex = rtm_msgindex(msgtype);

        if (rtnl_msg_handlers[protocol] == NULL)
                return -ENOENT;

        rtnl_msg_handlers[protocol][msgindex].doit = NULL;
        rtnl_msg_handlers[protocol][msgindex].dumpit = NULL;

        return 0;
}

EXPORT_SYMBOL_GPL(rtnl_unregister);

/**
 * rtnl_unregister_all - Unregister all rtnetlink message type of a protocol
 * @protocol : Protocol family or PF_UNSPEC
 *
 * Identical to calling rtnl_unregster() for all registered message types
 * of a certain protocol family.
 */
void rtnl_unregister_all(int protocol)
{
        BUG_ON(protocol < 0 || protocol >= NPROTO);

        kfree(rtnl_msg_handlers[protocol]);
        rtnl_msg_handlers[protocol] = NULL;
}

EXPORT_SYMBOL_GPL(rtnl_unregister_all);

static LIST_HEAD(link_ops);

/**
 * __rtnl_link_register - Register rtnl_link_ops with rtnetlink.
 * @ops: struct rtnl_link_ops * to register
 *
 * The caller must hold the rtnl_mutex. This function should be used
 * by drivers that create devices during module initialization. It
 * must be called before registering the devices.
 *
 * Returns 0 on success or a negative error code.
 */
int __rtnl_link_register(struct rtnl_link_ops *ops)
{
        if (!ops->dellink)
                ops->dellink = unregister_netdevice;

        list_add_tail(&ops->list, &link_ops);
        return 0;
}

EXPORT_SYMBOL_GPL(__rtnl_link_register);

/**
 * rtnl_link_register - Register rtnl_link_ops with rtnetlink.
 * @ops: struct rtnl_link_ops * to register
 *
 * Returns 0 on success or a negative error code.
 */
int rtnl_link_register(struct rtnl_link_ops *ops)
{
        int err;

        rtnl_lock();
        err = __rtnl_link_register(ops);
        rtnl_unlock();
        return err;
}

EXPORT_SYMBOL_GPL(rtnl_link_register);

static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops)
{
        struct net_device *dev;
restart:
        for_each_netdev(net, dev) {
                if (dev->rtnl_link_ops == ops) {
                        ops->dellink(dev);
                        goto restart;
                }
        }
}

void rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops)
{
        rtnl_lock();
        __rtnl_kill_links(net, ops);
        rtnl_unlock();
}
EXPORT_SYMBOL_GPL(rtnl_kill_links);

/**
 * __rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
 * @ops: struct rtnl_link_ops * to unregister
 *
 * The caller must hold the rtnl_mutex.
 */
void __rtnl_link_unregister(struct rtnl_link_ops *ops)
{
        struct net *net;

        for_each_net(net) {
                __rtnl_kill_links(net, ops);
        }
        list_del(&ops->list);
}

EXPORT_SYMBOL_GPL(__rtnl_link_unregister);

/**
 * rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
 * @ops: struct rtnl_link_ops * to unregister
 */
void rtnl_link_unregister(struct rtnl_link_ops *ops)
{
        rtnl_lock();
        __rtnl_link_unregister(ops);
        rtnl_unlock();
}

EXPORT_SYMBOL_GPL(rtnl_link_unregister);

static const struct rtnl_link_ops *rtnl_link_ops_get(const char *kind)
{
        const struct rtnl_link_ops *ops;

        list_for_each_entry(ops, &link_ops, list) {
                if (!strcmp(ops->kind, kind))
                        return ops;
        }
        return NULL;
}

static size_t rtnl_link_get_size(const struct net_device *dev)
{
        const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
        size_t size;

        if (!ops)
                return 0;

        size = nlmsg_total_size(sizeof(struct nlattr)) + /* IFLA_LINKINFO */
               nlmsg_total_size(strlen(ops->kind) + 1);  /* IFLA_INFO_KIND */

        if (ops->get_size)
                /* IFLA_INFO_DATA + nested data */
                size += nlmsg_total_size(sizeof(struct nlattr)) +
                        ops->get_size(dev);

        if (ops->get_xstats_size)
                size += ops->get_xstats_size(dev);      /* IFLA_INFO_XSTATS */

        return size;
}

static int rtnl_link_fill(struct sk_buff *skb, const struct net_device *dev)
{
        const struct rtnl_link_ops *ops = dev->rtnl_link_ops;
        struct nlattr *linkinfo, *data;
        int err = -EMSGSIZE;

        linkinfo = nla_nest_start(skb, IFLA_LINKINFO);
        if (linkinfo == NULL)
                goto out;

        if (nla_put_string(skb, IFLA_INFO_KIND, ops->kind) < 0)
                goto err_cancel_link;
        if (ops->fill_xstats) {
                err = ops->fill_xstats(skb, dev);
                if (err < 0)
                        goto err_cancel_link;
        }
        if (ops->fill_info) {
                data = nla_nest_start(skb, IFLA_INFO_DATA);
                if (data == NULL)
                        goto err_cancel_link;
                err = ops->fill_info(skb, dev);
                if (err < 0)
                        goto err_cancel_data;
                nla_nest_end(skb, data);
        }

        nla_nest_end(skb, linkinfo);
        return 0;

err_cancel_data:
        nla_nest_cancel(skb, data);
err_cancel_link:
        nla_nest_cancel(skb, linkinfo);
out:
        return err;
}

static const int rtm_min[RTM_NR_FAMILIES] =
{
        [RTM_FAM(RTM_NEWLINK)]      = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
        [RTM_FAM(RTM_NEWADDR)]      = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
        [RTM_FAM(RTM_NEWROUTE)]     = NLMSG_LENGTH(sizeof(struct rtmsg)),
        [RTM_FAM(RTM_NEWRULE)]      = NLMSG_LENGTH(sizeof(struct fib_rule_hdr)),
        [RTM_FAM(RTM_NEWQDISC)]     = NLMSG_LENGTH(sizeof(struct tcmsg)),
        [RTM_FAM(RTM_NEWTCLASS)]    = NLMSG_LENGTH(sizeof(struct tcmsg)),
        [RTM_FAM(RTM_NEWTFILTER)]   = NLMSG_LENGTH(sizeof(struct tcmsg)),
        [RTM_FAM(RTM_NEWACTION)]    = NLMSG_LENGTH(sizeof(struct tcamsg)),
        [RTM_FAM(RTM_GETMULTICAST)] = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
        [RTM_FAM(RTM_GETANYCAST)]   = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
};

static const int rta_max[RTM_NR_FAMILIES] =
{
        [RTM_FAM(RTM_NEWLINK)]      = IFLA_MAX,
        [RTM_FAM(RTM_NEWADDR)]      = IFA_MAX,
        [RTM_FAM(RTM_NEWROUTE)]     = RTA_MAX,
        [RTM_FAM(RTM_NEWRULE)]      = FRA_MAX,
        [RTM_FAM(RTM_NEWQDISC)]     = TCA_MAX,
        [RTM_FAM(RTM_NEWTCLASS)]    = TCA_MAX,
        [RTM_FAM(RTM_NEWTFILTER)]   = TCA_MAX,
        [RTM_FAM(RTM_NEWACTION)]    = TCAA_MAX,
};

#ifndef DDE_LINUX
void __rta_fill(struct sk_buff *skb, int attrtype, int attrlen, const void *data)
{
        struct rtattr *rta;
        int size = RTA_LENGTH(attrlen);

        rta = (struct rtattr*)skb_put(skb, RTA_ALIGN(size));
        rta->rta_type = attrtype;
        rta->rta_len = size;
        memcpy(RTA_DATA(rta), data, attrlen);
        memset(RTA_DATA(rta) + attrlen, 0, RTA_ALIGN(size) - size);
}

int rtnetlink_send(struct sk_buff *skb, struct net *net, u32 pid, unsigned group, int echo)
{
        struct sock *rtnl = net->rtnl;
        int err = 0;

        NETLINK_CB(skb).dst_group = group;
        if (echo)
                atomic_inc(&skb->users);
        netlink_broadcast(rtnl, skb, pid, group, GFP_KERNEL);
        if (echo)
                err = netlink_unicast(rtnl, skb, pid, MSG_DONTWAIT);
        return err;
}

int rtnl_unicast(struct sk_buff *skb, struct net *net, u32 pid)
{
        struct sock *rtnl = net->rtnl;

        return nlmsg_unicast(rtnl, skb, pid);
}

int rtnl_notify(struct sk_buff *skb, struct net *net, u32 pid, u32 group,
                struct nlmsghdr *nlh, gfp_t flags)
{
        struct sock *rtnl = net->rtnl;
        int report = 0;

        if (nlh)
                report = nlmsg_report(nlh);

        return nlmsg_notify(rtnl, skb, pid, group, report, flags);
}

void rtnl_set_sk_err(struct net *net, u32 group, int error)
{
        struct sock *rtnl = net->rtnl;

        netlink_set_err(rtnl, 0, group, error);
}

int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
{
        struct nlattr *mx;
        int i, valid = 0;

        mx = nla_nest_start(skb, RTA_METRICS);
        if (mx == NULL)
                return -ENOBUFS;

        for (i = 0; i < RTAX_MAX; i++) {
                if (metrics[i]) {
                        valid++;
                        NLA_PUT_U32(skb, i+1, metrics[i]);
                }
        }

        if (!valid) {
                nla_nest_cancel(skb, mx);
                return 0;
        }

        return nla_nest_end(skb, mx);

nla_put_failure:
        nla_nest_cancel(skb, mx);
        return -EMSGSIZE;
}

int rtnl_put_cacheinfo(struct sk_buff *skb, struct dst_entry *dst, u32 id,
                       u32 ts, u32 tsage, long expires, u32 error)
{
        struct rta_cacheinfo ci = {
                .rta_lastuse = jiffies_to_clock_t(jiffies - dst->lastuse),
                .rta_used = dst->__use,
                .rta_clntref = atomic_read(&(dst->__refcnt)),
                .rta_error = error,
                .rta_id =  id,
                .rta_ts = ts,
                .rta_tsage = tsage,
        };

        if (expires)
                ci.rta_expires = jiffies_to_clock_t(expires);

        return nla_put(skb, RTA_CACHEINFO, sizeof(ci), &ci);
}

EXPORT_SYMBOL_GPL(rtnl_put_cacheinfo);

static void set_operstate(struct net_device *dev, unsigned char transition)
{
        unsigned char operstate = dev->operstate;

        switch(transition) {
        case IF_OPER_UP:
                if ((operstate == IF_OPER_DORMANT ||
                     operstate == IF_OPER_UNKNOWN) &&
                    !netif_dormant(dev))
                        operstate = IF_OPER_UP;
                break;

        case IF_OPER_DORMANT:
                if (operstate == IF_OPER_UP ||
                    operstate == IF_OPER_UNKNOWN)
                        operstate = IF_OPER_DORMANT;
                break;
        }

        if (dev->operstate != operstate) {
                write_lock_bh(&dev_base_lock);
                dev->operstate = operstate;
                write_unlock_bh(&dev_base_lock);
                netdev_state_change(dev);
        }
}

static void copy_rtnl_link_stats(struct rtnl_link_stats *a,
                                 const struct net_device_stats *b)
{
        a->rx_packets = b->rx_packets;
        a->tx_packets = b->tx_packets;
        a->rx_bytes = b->rx_bytes;
        a->tx_bytes = b->tx_bytes;
        a->rx_errors = b->rx_errors;
        a->tx_errors = b->tx_errors;
        a->rx_dropped = b->rx_dropped;
        a->tx_dropped = b->tx_dropped;

        a->multicast = b->multicast;
        a->collisions = b->collisions;

        a->rx_length_errors = b->rx_length_errors;
        a->rx_over_errors = b->rx_over_errors;
        a->rx_crc_errors = b->rx_crc_errors;
        a->rx_frame_errors = b->rx_frame_errors;
        a->rx_fifo_errors = b->rx_fifo_errors;
        a->rx_missed_errors = b->rx_missed_errors;

        a->tx_aborted_errors = b->tx_aborted_errors;
        a->tx_carrier_errors = b->tx_carrier_errors;
        a->tx_fifo_errors = b->tx_fifo_errors;
        a->tx_heartbeat_errors = b->tx_heartbeat_errors;
        a->tx_window_errors = b->tx_window_errors;

        a->rx_compressed = b->rx_compressed;
        a->tx_compressed = b->tx_compressed;
};

static inline size_t if_nlmsg_size(const struct net_device *dev)
{
        return NLMSG_ALIGN(sizeof(struct ifinfomsg))
               + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
               + nla_total_size(IFALIASZ) /* IFLA_IFALIAS */
               + nla_total_size(IFNAMSIZ) /* IFLA_QDISC */
               + nla_total_size(sizeof(struct rtnl_link_ifmap))
               + nla_total_size(sizeof(struct rtnl_link_stats))
               + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
               + nla_total_size(MAX_ADDR_LEN) /* IFLA_BROADCAST */
               + nla_total_size(4) /* IFLA_TXQLEN */
               + nla_total_size(4) /* IFLA_WEIGHT */
               + nla_total_size(4) /* IFLA_MTU */
               + nla_total_size(4) /* IFLA_LINK */
               + nla_total_size(4) /* IFLA_MASTER */
               + nla_total_size(1) /* IFLA_OPERSTATE */
               + nla_total_size(1) /* IFLA_LINKMODE */
               + rtnl_link_get_size(dev); /* IFLA_LINKINFO */
}

static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
                            int type, u32 pid, u32 seq, u32 change,
                            unsigned int flags)
{
        struct netdev_queue *txq;
        struct ifinfomsg *ifm;
        struct nlmsghdr *nlh;
        const struct net_device_stats *stats;
        struct nlattr *attr;

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

        ifm = nlmsg_data(nlh);
        ifm->ifi_family = AF_UNSPEC;
        ifm->__ifi_pad = 0;
        ifm->ifi_type = dev->type;
        ifm->ifi_index = dev->ifindex;
        ifm->ifi_flags = dev_get_flags(dev);
        ifm->ifi_change = change;

        NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
        NLA_PUT_U32(skb, IFLA_TXQLEN, dev->tx_queue_len);
        NLA_PUT_U8(skb, IFLA_OPERSTATE,
                   netif_running(dev) ? dev->operstate : IF_OPER_DOWN);
        NLA_PUT_U8(skb, IFLA_LINKMODE, dev->link_mode);
        NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);

        if (dev->ifindex != dev->iflink)
                NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);

        if (dev->master)
                NLA_PUT_U32(skb, IFLA_MASTER, dev->master->ifindex);

        txq = netdev_get_tx_queue(dev, 0);
        if (txq->qdisc_sleeping)
                NLA_PUT_STRING(skb, IFLA_QDISC, txq->qdisc_sleeping->ops->id);

        if (dev->ifalias)
                NLA_PUT_STRING(skb, IFLA_IFALIAS, dev->ifalias);

        if (1) {
                struct rtnl_link_ifmap map = {
                        .mem_start   = dev->mem_start,
                        .mem_end     = dev->mem_end,
                        .base_addr   = dev->base_addr,
                        .irq         = dev->irq,
                        .dma         = dev->dma,
                        .port        = dev->if_port,
                };
                NLA_PUT(skb, IFLA_MAP, sizeof(map), &map);
        }

        if (dev->addr_len) {
                NLA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
                NLA_PUT(skb, IFLA_BROADCAST, dev->addr_len, dev->broadcast);
        }

        attr = nla_reserve(skb, IFLA_STATS,
                        sizeof(struct rtnl_link_stats));
        if (attr == NULL)
                goto nla_put_failure;

        stats = dev_get_stats(dev);
        copy_rtnl_link_stats(nla_data(attr), stats);

        if (dev->rtnl_link_ops) {
                if (rtnl_link_fill(skb, dev) < 0)
                        goto nla_put_failure;
        }

        return nlmsg_end(skb, nlh);

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

static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        int idx;
        int s_idx = cb->args[0];
        struct net_device *dev;

        idx = 0;
        for_each_netdev(net, dev) {
                if (idx < s_idx)
                        goto cont;
                if (rtnl_fill_ifinfo(skb, dev, RTM_NEWLINK,
                                     NETLINK_CB(cb->skb).pid,
                                     cb->nlh->nlmsg_seq, 0, NLM_F_MULTI) <= 0)
                        break;
cont:
                idx++;
        }
        cb->args[0] = idx;

        return skb->len;
}

const struct nla_policy ifla_policy[IFLA_MAX+1] = {
        [IFLA_IFNAME]           = { .type = NLA_STRING, .len = IFNAMSIZ-1 },
        [IFLA_ADDRESS]          = { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
        [IFLA_BROADCAST]        = { .type = NLA_BINARY, .len = MAX_ADDR_LEN },
        [IFLA_MAP]              = { .len = sizeof(struct rtnl_link_ifmap) },
        [IFLA_MTU]              = { .type = NLA_U32 },
        [IFLA_LINK]             = { .type = NLA_U32 },
        [IFLA_TXQLEN]           = { .type = NLA_U32 },
        [IFLA_WEIGHT]           = { .type = NLA_U32 },
        [IFLA_OPERSTATE]        = { .type = NLA_U8 },
        [IFLA_LINKMODE]         = { .type = NLA_U8 },
        [IFLA_LINKINFO]         = { .type = NLA_NESTED },
        [IFLA_NET_NS_PID]       = { .type = NLA_U32 },
        [IFLA_IFALIAS]          = { .type = NLA_STRING, .len = IFALIASZ-1 },
};

static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
        [IFLA_INFO_KIND]        = { .type = NLA_STRING },
        [IFLA_INFO_DATA]        = { .type = NLA_NESTED },
};

static struct net *get_net_ns_by_pid(pid_t pid)
{
        struct task_struct *tsk;
        struct net *net;

        /* Lookup the network namespace */
        net = ERR_PTR(-ESRCH);
        rcu_read_lock();
        tsk = find_task_by_vpid(pid);
        if (tsk) {
                struct nsproxy *nsproxy;
                nsproxy = task_nsproxy(tsk);
                if (nsproxy)
                        net = get_net(nsproxy->net_ns);
        }
        rcu_read_unlock();
        return net;
}

static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[])
{
        if (dev) {
                if (tb[IFLA_ADDRESS] &&
                    nla_len(tb[IFLA_ADDRESS]) < dev->addr_len)
                        return -EINVAL;

                if (tb[IFLA_BROADCAST] &&
                    nla_len(tb[IFLA_BROADCAST]) < dev->addr_len)
                        return -EINVAL;
        }

        return 0;
}

static int do_setlink(struct net_device *dev, struct ifinfomsg *ifm,
                      struct nlattr **tb, char *ifname, int modified)
{
        const struct net_device_ops *ops = dev->netdev_ops;
        int send_addr_notify = 0;
        int err;

        if (tb[IFLA_NET_NS_PID]) {
                struct net *net;
                net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));
                if (IS_ERR(net)) {
                        err = PTR_ERR(net);
                        goto errout;
                }
                err = dev_change_net_namespace(dev, net, ifname);
                put_net(net);
                if (err)
                        goto errout;
                modified = 1;
        }

        if (tb[IFLA_MAP]) {
                struct rtnl_link_ifmap *u_map;
                struct ifmap k_map;

                if (!ops->ndo_set_config) {
                        err = -EOPNOTSUPP;
                        goto errout;
                }

                if (!netif_device_present(dev)) {
                        err = -ENODEV;
                        goto errout;
                }

                u_map = nla_data(tb[IFLA_MAP]);
                k_map.mem_start = (unsigned long) u_map->mem_start;
                k_map.mem_end = (unsigned long) u_map->mem_end;
                k_map.base_addr = (unsigned short) u_map->base_addr;
                k_map.irq = (unsigned char) u_map->irq;
                k_map.dma = (unsigned char) u_map->dma;
                k_map.port = (unsigned char) u_map->port;

                err = ops->ndo_set_config(dev, &k_map);
                if (err < 0)
                        goto errout;

                modified = 1;
        }

        if (tb[IFLA_ADDRESS]) {
                struct sockaddr *sa;
                int len;

                if (!ops->ndo_set_mac_address) {
                        err = -EOPNOTSUPP;
                        goto errout;
                }

                if (!netif_device_present(dev)) {
                        err = -ENODEV;
                        goto errout;
                }

                len = sizeof(sa_family_t) + dev->addr_len;
                sa = kmalloc(len, GFP_KERNEL);
                if (!sa) {
                        err = -ENOMEM;
                        goto errout;
                }
                sa->sa_family = dev->type;
                memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]),
                       dev->addr_len);
                err = ops->ndo_set_mac_address(dev, sa);
                kfree(sa);
                if (err)
                        goto errout;
                send_addr_notify = 1;
                modified = 1;
        }

        if (tb[IFLA_MTU]) {
                err = dev_set_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
                if (err < 0)
                        goto errout;
                modified = 1;
        }

        /*
         * Interface selected by interface index but interface
         * name provided implies that a name change has been
         * requested.
         */
        if (ifm->ifi_index > 0 && ifname[0]) {
                err = dev_change_name(dev, ifname);
                if (err < 0)
                        goto errout;
                modified = 1;
        }

        if (tb[IFLA_IFALIAS]) {
                err = dev_set_alias(dev, nla_data(tb[IFLA_IFALIAS]),
                                    nla_len(tb[IFLA_IFALIAS]));
                if (err < 0)
                        goto errout;
                modified = 1;
        }

        if (tb[IFLA_BROADCAST]) {
                nla_memcpy(dev->broadcast, tb[IFLA_BROADCAST], dev->addr_len);
                send_addr_notify = 1;
        }

        if (ifm->ifi_flags || ifm->ifi_change) {
                unsigned int flags = ifm->ifi_flags;

                /* bugwards compatibility: ifi_change == 0 is treated as ~0 */
                if (ifm->ifi_change)
                        flags = (flags & ifm->ifi_change) |
                                (dev->flags & ~ifm->ifi_change);
                err = dev_change_flags(dev, flags);
                if (err < 0)
                        goto errout;
        }

        if (tb[IFLA_TXQLEN])
                dev->tx_queue_len = nla_get_u32(tb[IFLA_TXQLEN]);

        if (tb[IFLA_OPERSTATE])
                set_operstate(dev, nla_get_u8(tb[IFLA_OPERSTATE]));

        if (tb[IFLA_LINKMODE]) {
                write_lock_bh(&dev_base_lock);
                dev->link_mode = nla_get_u8(tb[IFLA_LINKMODE]);
                write_unlock_bh(&dev_base_lock);
        }

        err = 0;

errout:
        if (err < 0 && modified && net_ratelimit())
                printk(KERN_WARNING "A link change request failed with "
                       "some changes comitted already. Interface %s may "
                       "have been left with an inconsistent configuration, "
                       "please check.\n", dev->name);

        if (send_addr_notify)
                call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
        return err;
}

static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        struct ifinfomsg *ifm;
        struct net_device *dev;
        int err;
        struct nlattr *tb[IFLA_MAX+1];
        char ifname[IFNAMSIZ];

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

        if (tb[IFLA_IFNAME])
                nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
        else
                ifname[0] = '\0';

        err = -EINVAL;
        ifm = nlmsg_data(nlh);
        if (ifm->ifi_index > 0)
                dev = dev_get_by_index(net, ifm->ifi_index);
        else if (tb[IFLA_IFNAME])
                dev = dev_get_by_name(net, ifname);
        else
                goto errout;

        if (dev == NULL) {
                err = -ENODEV;
                goto errout;
        }

        if ((err = validate_linkmsg(dev, tb)) < 0)
                goto errout_dev;

        err = do_setlink(dev, ifm, tb, ifname, 0);
errout_dev:
        dev_put(dev);
errout:
        return err;
}

static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        const struct rtnl_link_ops *ops;
        struct net_device *dev;
        struct ifinfomsg *ifm;
        char ifname[IFNAMSIZ];
        struct nlattr *tb[IFLA_MAX+1];
        int err;

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

        if (tb[IFLA_IFNAME])
                nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);

        ifm = nlmsg_data(nlh);
        if (ifm->ifi_index > 0)
                dev = __dev_get_by_index(net, ifm->ifi_index);
        else if (tb[IFLA_IFNAME])
                dev = __dev_get_by_name(net, ifname);
        else
                return -EINVAL;

        if (!dev)
                return -ENODEV;

        ops = dev->rtnl_link_ops;
        if (!ops)
                return -EOPNOTSUPP;

        ops->dellink(dev);
        return 0;
}

struct net_device *rtnl_create_link(struct net *net, char *ifname,
                const struct rtnl_link_ops *ops, struct nlattr *tb[])
{
        int err;
        struct net_device *dev;

        err = -ENOMEM;
        dev = alloc_netdev(ops->priv_size, ifname, ops->setup);
        if (!dev)
                goto err;

        if (strchr(dev->name, '%')) {
                err = dev_alloc_name(dev, dev->name);
                if (err < 0)
                        goto err_free;
        }

        dev_net_set(dev, net);
        dev->rtnl_link_ops = ops;

        if (tb[IFLA_MTU])
                dev->mtu = nla_get_u32(tb[IFLA_MTU]);
        if (tb[IFLA_ADDRESS])
                memcpy(dev->dev_addr, nla_data(tb[IFLA_ADDRESS]),
                                nla_len(tb[IFLA_ADDRESS]));
        if (tb[IFLA_BROADCAST])
                memcpy(dev->broadcast, nla_data(tb[IFLA_BROADCAST]),
                                nla_len(tb[IFLA_BROADCAST]));
        if (tb[IFLA_TXQLEN])
                dev->tx_queue_len = nla_get_u32(tb[IFLA_TXQLEN]);
        if (tb[IFLA_OPERSTATE])
                set_operstate(dev, nla_get_u8(tb[IFLA_OPERSTATE]));
        if (tb[IFLA_LINKMODE])
                dev->link_mode = nla_get_u8(tb[IFLA_LINKMODE]);

        return dev;

err_free:
        free_netdev(dev);
err:
        return ERR_PTR(err);
}

static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        const struct rtnl_link_ops *ops;
        struct net_device *dev;
        struct ifinfomsg *ifm;
        char kind[MODULE_NAME_LEN];
        char ifname[IFNAMSIZ];
        struct nlattr *tb[IFLA_MAX+1];
        struct nlattr *linkinfo[IFLA_INFO_MAX+1];
        int err;

#ifdef CONFIG_MODULES
replay:
#endif
        err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFLA_MAX, ifla_policy);
        if (err < 0)
                return err;

        if (tb[IFLA_IFNAME])
                nla_strlcpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
        else
                ifname[0] = '\0';

        ifm = nlmsg_data(nlh);
        if (ifm->ifi_index > 0)
                dev = __dev_get_by_index(net, ifm->ifi_index);
        else if (ifname[0])
                dev = __dev_get_by_name(net, ifname);
        else
                dev = NULL;

        if ((err = validate_linkmsg(dev, tb)) < 0)
                return err;

        if (tb[IFLA_LINKINFO]) {
                err = nla_parse_nested(linkinfo, IFLA_INFO_MAX,
                                       tb[IFLA_LINKINFO], ifla_info_policy);
                if (err < 0)
                        return err;
        } else
                memset(linkinfo, 0, sizeof(linkinfo));

        if (linkinfo[IFLA_INFO_KIND]) {
                nla_strlcpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
                ops = rtnl_link_ops_get(kind);
        } else {
                kind[0] = '\0';
                ops = NULL;
        }

        if (1) {
                struct nlattr *attr[ops ? ops->maxtype + 1 : 0], **data = NULL;

                if (ops) {
                        if (ops->maxtype && linkinfo[IFLA_INFO_DATA]) {
                                err = nla_parse_nested(attr, ops->maxtype,
                                                       linkinfo[IFLA_INFO_DATA],
                                                       ops->policy);
                                if (err < 0)
                                        return err;
                                data = attr;
                        }
                        if (ops->validate) {
                                err = ops->validate(tb, data);
                                if (err < 0)
                                        return err;
                        }
                }

                if (dev) {
                        int modified = 0;

                        if (nlh->nlmsg_flags & NLM_F_EXCL)
                                return -EEXIST;
                        if (nlh->nlmsg_flags & NLM_F_REPLACE)
                                return -EOPNOTSUPP;

                        if (linkinfo[IFLA_INFO_DATA]) {
                                if (!ops || ops != dev->rtnl_link_ops ||
                                    !ops->changelink)
                                        return -EOPNOTSUPP;

                                err = ops->changelink(dev, tb, data);
                                if (err < 0)
                                        return err;
                                modified = 1;
                        }

                        return do_setlink(dev, ifm, tb, ifname, modified);
                }

                if (!(nlh->nlmsg_flags & NLM_F_CREATE))
                        return -ENODEV;

                if (ifm->ifi_index || ifm->ifi_flags || ifm->ifi_change)
                        return -EOPNOTSUPP;
                if (tb[IFLA_MAP] || tb[IFLA_MASTER] || tb[IFLA_PROTINFO])
                        return -EOPNOTSUPP;

                if (!ops) {
#ifdef CONFIG_MODULES
                        if (kind[0]) {
                                __rtnl_unlock();
                                request_module("rtnl-link-%s", kind);
                                rtnl_lock();
                                ops = rtnl_link_ops_get(kind);
                                if (ops)
                                        goto replay;
                        }
#endif
                        return -EOPNOTSUPP;
                }

                if (!ifname[0])
                        snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);

                dev = rtnl_create_link(net, ifname, ops, tb);

                if (IS_ERR(dev))
                        err = PTR_ERR(dev);
                else if (ops->newlink)
                        err = ops->newlink(dev, tb, data);
                else
                        err = register_netdevice(dev);

                if (err < 0 && !IS_ERR(dev))
                        free_netdev(dev);
                return err;
        }
}

static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
        struct net *net = sock_net(skb->sk);
        struct ifinfomsg *ifm;
        struct nlattr *tb[IFLA_MAX+1];
        struct net_device *dev = NULL;
        struct sk_buff *nskb;
        int err;

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

        ifm = nlmsg_data(nlh);
        if (ifm->ifi_index > 0) {
                dev = dev_get_by_index(net, ifm->ifi_index);
                if (dev == NULL)
                        return -ENODEV;
        } else
                return -EINVAL;

        nskb = nlmsg_new(if_nlmsg_size(dev), GFP_KERNEL);
        if (nskb == NULL) {
                err = -ENOBUFS;
                goto errout;
        }

        err = rtnl_fill_ifinfo(nskb, dev, RTM_NEWLINK, NETLINK_CB(skb).pid,
                               nlh->nlmsg_seq, 0, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in if_nlmsg_size */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(nskb);
                goto errout;
        }
        err = rtnl_unicast(nskb, net, NETLINK_CB(skb).pid);
errout:
        dev_put(dev);

        return err;
}

static int rtnl_dump_all(struct sk_buff *skb, struct netlink_callback *cb)
{
        int idx;
        int s_idx = cb->family;

        if (s_idx == 0)
                s_idx = 1;
        for (idx=1; idx<NPROTO; idx++) {
                int type = cb->nlh->nlmsg_type-RTM_BASE;
                if (idx < s_idx || idx == PF_PACKET)
                        continue;
                if (rtnl_msg_handlers[idx] == NULL ||
                    rtnl_msg_handlers[idx][type].dumpit == NULL)
                        continue;
                if (idx > s_idx)
                        memset(&cb->args[0], 0, sizeof(cb->args));
                if (rtnl_msg_handlers[idx][type].dumpit(skb, cb))
                        break;
        }
        cb->family = idx;

        return skb->len;
}
#endif /* DDE_LINUX */

void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change)
{
        struct net *net = dev_net(dev);
#ifndef DDE_LINUX
        struct sk_buff *skb;
        int err = -ENOBUFS;

        skb = nlmsg_new(if_nlmsg_size(dev), GFP_KERNEL);
        if (skb == NULL)
                goto errout;

        err = rtnl_fill_ifinfo(skb, dev, type, 0, 0, change, 0);
        if (err < 0) {
                /* -EMSGSIZE implies BUG in if_nlmsg_size() */
                WARN_ON(err == -EMSGSIZE);
                kfree_skb(skb);
                goto errout;
        }
        err = rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_KERNEL);
errout:
        if (err < 0)
                rtnl_set_sk_err(net, RTNLGRP_LINK, err);
#endif /* DDE_LINUX */
}

#ifndef DDE_LINUX
/* Protected by RTNL sempahore.  */
static struct rtattr **rta_buf;
static int rtattr_max;

/* Process one rtnetlink message. */

static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
        struct net *net = sock_net(skb->sk);
        rtnl_doit_func doit;
        int sz_idx, kind;
        int min_len;
        int family;
        int type;
        int err;

        type = nlh->nlmsg_type;
        if (type > RTM_MAX)
                return -EOPNOTSUPP;

        type -= RTM_BASE;

        /* All the messages must have at least 1 byte length */
        if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct rtgenmsg)))
                return 0;

        family = ((struct rtgenmsg*)NLMSG_DATA(nlh))->rtgen_family;
        if (family >= NPROTO)
                return -EAFNOSUPPORT;

        sz_idx = type>>2;
        kind = type&3;

        if (kind != 2 && security_netlink_recv(skb, CAP_NET_ADMIN))
                return -EPERM;

        if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
                struct sock *rtnl;
                rtnl_dumpit_func dumpit;

                dumpit = rtnl_get_dumpit(family, type);
                if (dumpit == NULL)
                        return -EOPNOTSUPP;

                __rtnl_unlock();
                rtnl = net->rtnl;
                err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL);
                rtnl_lock();
                return err;
        }

        memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *)));

        min_len = rtm_min[sz_idx];
        if (nlh->nlmsg_len < min_len)
                return -EINVAL;

        if (nlh->nlmsg_len > min_len) {
                int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
                struct rtattr *attr = (void*)nlh + NLMSG_ALIGN(min_len);

                while (RTA_OK(attr, attrlen)) {
                        unsigned flavor = attr->rta_type;
                        if (flavor) {
                                if (flavor > rta_max[sz_idx])
                                        return -EINVAL;
                                rta_buf[flavor-1] = attr;
                        }
                        attr = RTA_NEXT(attr, attrlen);
                }
        }

        doit = rtnl_get_doit(family, type);
        if (doit == NULL)
                return -EOPNOTSUPP;

        return doit(skb, nlh, (void *)&rta_buf[0]);
}

static void rtnetlink_rcv(struct sk_buff *skb)
{
        rtnl_lock();
        netlink_rcv_skb(skb, &rtnetlink_rcv_msg);
        rtnl_unlock();
}

static int rtnetlink_event(struct notifier_block *this, unsigned long event, void *ptr)
{
        struct net_device *dev = ptr;

        switch (event) {
        case NETDEV_UNREGISTER:
                rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
                break;
        case NETDEV_REGISTER:
                rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U);
                break;
        case NETDEV_UP:
        case NETDEV_DOWN:
                rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
                break;
        case NETDEV_CHANGE:
        case NETDEV_GOING_DOWN:
                break;
        default:
                rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
                break;
        }
        return NOTIFY_DONE;
}

static struct notifier_block rtnetlink_dev_notifier = {
        .notifier_call  = rtnetlink_event,
};


static int rtnetlink_net_init(struct net *net)
{
        struct sock *sk;
        sk = netlink_kernel_create(net, NETLINK_ROUTE, RTNLGRP_MAX,
                                   rtnetlink_rcv, &rtnl_mutex, THIS_MODULE);
        if (!sk)
                return -ENOMEM;
        net->rtnl = sk;
        return 0;
}

static void rtnetlink_net_exit(struct net *net)
{
        netlink_kernel_release(net->rtnl);
        net->rtnl = NULL;
}

static struct pernet_operations rtnetlink_net_ops = {
        .init = rtnetlink_net_init,
        .exit = rtnetlink_net_exit,
};

void __init rtnetlink_init(void)
{
        int i;

        rtattr_max = 0;
        for (i = 0; i < ARRAY_SIZE(rta_max); i++)
                if (rta_max[i] > rtattr_max)
                        rtattr_max = rta_max[i];
        rta_buf = kmalloc(rtattr_max * sizeof(struct rtattr *), GFP_KERNEL);
        if (!rta_buf)
                panic("rtnetlink_init: cannot allocate rta_buf\n");

        if (register_pernet_subsys(&rtnetlink_net_ops))
                panic("rtnetlink_init: cannot initialize rtnetlink\n");

        netlink_set_nonroot(NETLINK_ROUTE, NL_NONROOT_RECV);
        register_netdevice_notifier(&rtnetlink_dev_notifier);

        rtnl_register(PF_UNSPEC, RTM_GETLINK, rtnl_getlink, rtnl_dump_ifinfo);
        rtnl_register(PF_UNSPEC, RTM_SETLINK, rtnl_setlink, NULL);
        rtnl_register(PF_UNSPEC, RTM_NEWLINK, rtnl_newlink, NULL);
        rtnl_register(PF_UNSPEC, RTM_DELLINK, rtnl_dellink, NULL);

        rtnl_register(PF_UNSPEC, RTM_GETADDR, NULL, rtnl_dump_all);
        rtnl_register(PF_UNSPEC, RTM_GETROUTE, NULL, rtnl_dump_all);
}

EXPORT_SYMBOL(__rta_fill);
EXPORT_SYMBOL(rtnetlink_put_metrics);
EXPORT_SYMBOL(rtnl_lock);
EXPORT_SYMBOL(rtnl_trylock);
EXPORT_SYMBOL(rtnl_unlock);
EXPORT_SYMBOL(rtnl_is_locked);
EXPORT_SYMBOL(rtnl_unicast);
EXPORT_SYMBOL(rtnl_notify);
EXPORT_SYMBOL(rtnl_set_sk_err);
EXPORT_SYMBOL(rtnl_create_link);
EXPORT_SYMBOL(ifla_policy);
#endif /* !DDE_LINUX */

---