linux/net/bridge/br_netlink.c
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   1/*
   2 *      Bridge netlink control interface
   3 *
   4 *      Authors:
   5 *      Stephen Hemminger               <shemminger@osdl.org>
   6 *
   7 *      This program is free software; you can redistribute it and/or
   8 *      modify it under the terms of the GNU General Public License
   9 *      as published by the Free Software Foundation; either version
  10 *      2 of the License, or (at your option) any later version.
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/slab.h>
  15#include <linux/etherdevice.h>
  16#include <net/rtnetlink.h>
  17#include <net/net_namespace.h>
  18#include <net/sock.h>
  19
  20#include "br_private.h"
  21#include "br_private_stp.h"
  22
  23static inline size_t br_nlmsg_size(void)
  24{
  25        return NLMSG_ALIGN(sizeof(struct ifinfomsg))
  26               + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
  27               + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
  28               + nla_total_size(4) /* IFLA_MASTER */
  29               + nla_total_size(4) /* IFLA_MTU */
  30               + nla_total_size(4) /* IFLA_LINK */
  31               + nla_total_size(1) /* IFLA_OPERSTATE */
  32               + nla_total_size(1); /* IFLA_PROTINFO */
  33}
  34
  35/*
  36 * Create one netlink message for one interface
  37 * Contains port and master info as well as carrier and bridge state.
  38 */
  39static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
  40                          u32 pid, u32 seq, int event, unsigned int flags)
  41{
  42        const struct net_bridge *br = port->br;
  43        const struct net_device *dev = port->dev;
  44        struct ifinfomsg *hdr;
  45        struct nlmsghdr *nlh;
  46        u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
  47
  48        br_debug(br, "br_fill_info event %d port %s master %s\n",
  49                     event, dev->name, br->dev->name);
  50
  51        nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
  52        if (nlh == NULL)
  53                return -EMSGSIZE;
  54
  55        hdr = nlmsg_data(nlh);
  56        hdr->ifi_family = AF_BRIDGE;
  57        hdr->__ifi_pad = 0;
  58        hdr->ifi_type = dev->type;
  59        hdr->ifi_index = dev->ifindex;
  60        hdr->ifi_flags = dev_get_flags(dev);
  61        hdr->ifi_change = 0;
  62
  63        if (nla_put_string(skb, IFLA_IFNAME, dev->name) ||
  64            nla_put_u32(skb, IFLA_MASTER, br->dev->ifindex) ||
  65            nla_put_u32(skb, IFLA_MTU, dev->mtu) ||
  66            nla_put_u8(skb, IFLA_OPERSTATE, operstate) ||
  67            (dev->addr_len &&
  68             nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr)) ||
  69            (dev->ifindex != dev->iflink &&
  70             nla_put_u32(skb, IFLA_LINK, dev->iflink)) ||
  71            (event == RTM_NEWLINK &&
  72             nla_put_u8(skb, IFLA_PROTINFO, port->state)))
  73                goto nla_put_failure;
  74        return nlmsg_end(skb, nlh);
  75
  76nla_put_failure:
  77        nlmsg_cancel(skb, nlh);
  78        return -EMSGSIZE;
  79}
  80
  81/*
  82 * Notify listeners of a change in port information
  83 */
  84void br_ifinfo_notify(int event, struct net_bridge_port *port)
  85{
  86        struct net *net = dev_net(port->dev);
  87        struct sk_buff *skb;
  88        int err = -ENOBUFS;
  89
  90        br_debug(port->br, "port %u(%s) event %d\n",
  91                 (unsigned int)port->port_no, port->dev->name, event);
  92
  93        skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
  94        if (skb == NULL)
  95                goto errout;
  96
  97        err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
  98        if (err < 0) {
  99                /* -EMSGSIZE implies BUG in br_nlmsg_size() */
 100                WARN_ON(err == -EMSGSIZE);
 101                kfree_skb(skb);
 102                goto errout;
 103        }
 104        rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 105        return;
 106errout:
 107        if (err < 0)
 108                rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 109}
 110
 111/*
 112 * Dump information about all ports, in response to GETLINK
 113 */
 114static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 115{
 116        struct net *net = sock_net(skb->sk);
 117        struct net_device *dev;
 118        int idx;
 119
 120        idx = 0;
 121        rcu_read_lock();
 122        for_each_netdev_rcu(net, dev) {
 123                struct net_bridge_port *port = br_port_get_rcu(dev);
 124
 125                /* not a bridge port */
 126                if (!port || idx < cb->args[0])
 127                        goto skip;
 128
 129                if (br_fill_ifinfo(skb, port,
 130                                   NETLINK_CB(cb->skb).pid,
 131                                   cb->nlh->nlmsg_seq, RTM_NEWLINK,
 132                                   NLM_F_MULTI) < 0)
 133                        break;
 134skip:
 135                ++idx;
 136        }
 137        rcu_read_unlock();
 138        cb->args[0] = idx;
 139
 140        return skb->len;
 141}
 142
 143/*
 144 * Change state of port (ie from forwarding to blocking etc)
 145 * Used by spanning tree in user space.
 146 */
 147static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 148{
 149        struct net *net = sock_net(skb->sk);
 150        struct ifinfomsg *ifm;
 151        struct nlattr *protinfo;
 152        struct net_device *dev;
 153        struct net_bridge_port *p;
 154        u8 new_state;
 155
 156        if (nlmsg_len(nlh) < sizeof(*ifm))
 157                return -EINVAL;
 158
 159        ifm = nlmsg_data(nlh);
 160        if (ifm->ifi_family != AF_BRIDGE)
 161                return -EPFNOSUPPORT;
 162
 163        protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);
 164        if (!protinfo || nla_len(protinfo) < sizeof(u8))
 165                return -EINVAL;
 166
 167        new_state = nla_get_u8(protinfo);
 168        if (new_state > BR_STATE_BLOCKING)
 169                return -EINVAL;
 170
 171        dev = __dev_get_by_index(net, ifm->ifi_index);
 172        if (!dev)
 173                return -ENODEV;
 174
 175        p = br_port_get_rtnl(dev);
 176        if (!p)
 177                return -EINVAL;
 178
 179        /* if kernel STP is running, don't allow changes */
 180        if (p->br->stp_enabled == BR_KERNEL_STP)
 181                return -EBUSY;
 182
 183        if (!netif_running(dev) ||
 184            (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED))
 185                return -ENETDOWN;
 186
 187        p->state = new_state;
 188        br_log_state(p);
 189
 190        spin_lock_bh(&p->br->lock);
 191        br_port_state_selection(p->br);
 192        spin_unlock_bh(&p->br->lock);
 193
 194        br_ifinfo_notify(RTM_NEWLINK, p);
 195
 196        return 0;
 197}
 198
 199static int br_validate(struct nlattr *tb[], struct nlattr *data[])
 200{
 201        if (tb[IFLA_ADDRESS]) {
 202                if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 203                        return -EINVAL;
 204                if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 205                        return -EADDRNOTAVAIL;
 206        }
 207
 208        return 0;
 209}
 210
 211struct rtnl_link_ops br_link_ops __read_mostly = {
 212        .kind           = "bridge",
 213        .priv_size      = sizeof(struct net_bridge),
 214        .setup          = br_dev_setup,
 215        .validate       = br_validate,
 216        .dellink        = br_dev_delete,
 217};
 218
 219int __init br_netlink_init(void)
 220{
 221        int err;
 222
 223        err = rtnl_link_register(&br_link_ops);
 224        if (err < 0)
 225                goto err1;
 226
 227        err = __rtnl_register(PF_BRIDGE, RTM_GETLINK, NULL,
 228                              br_dump_ifinfo, NULL);
 229        if (err)
 230                goto err2;
 231        err = __rtnl_register(PF_BRIDGE, RTM_SETLINK,
 232                              br_rtm_setlink, NULL, NULL);
 233        if (err)
 234                goto err3;
 235
 236        return 0;
 237
 238err3:
 239        rtnl_unregister_all(PF_BRIDGE);
 240err2:
 241        rtnl_link_unregister(&br_link_ops);
 242err1:
 243        return err;
 244}
 245
 246void __exit br_netlink_fini(void)
 247{
 248        rtnl_link_unregister(&br_link_ops);
 249        rtnl_unregister_all(PF_BRIDGE);
 250}
 251
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