net/bridge/br_netlink.c

   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
  23 static 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  */
  39 static 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
  76 nla_put_failure:
  77         nlmsg_cancel(skb, nlh);
  78         return -EMSGSIZE;
  79 }
  80
  81 /*
  82  * Notify listeners of a change in port information
  83  */
  84 void 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;
 106 errout:
 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  */
 114 static 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).portid,
 131                                    cb->nlh->nlmsg_seq, RTM_NEWLINK,
 132                                    NLM_F_MULTI) < 0)
 133                         break;
 134 skip:
 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  */
 147 static 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
 199 static 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
 211 struct 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
 219 int __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
 238 err3:
 239         rtnl_unregister_all(PF_BRIDGE);
 240 err2:
 241         rtnl_link_unregister(&br_link_ops);
 242 err1:
 243         return err;
 244 }
 245
 246 void __exit br_netlink_fini(void)
 247 {
 248         rtnl_link_unregister(&br_link_ops);
 249         rtnl_unregister_all(PF_BRIDGE);
 250 }