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
  22 static inline size_t br_nlmsg_size(void)
  23 {
  24         return NLMSG_ALIGN(sizeof(struct ifinfomsg))
  25                + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
  26                + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
  27                + nla_total_size(4) /* IFLA_MASTER */
  28                + nla_total_size(4) /* IFLA_MTU */
  29                + nla_total_size(4) /* IFLA_LINK */
  30                + nla_total_size(1) /* IFLA_OPERSTATE */
  31                + nla_total_size(1); /* IFLA_PROTINFO */
  32 }
  33
  34 /*
  35  * Create one netlink message for one interface
  36  * Contains port and master info as well as carrier and bridge state.
  37  */
  38 static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
  39                           u32 pid, u32 seq, int event, unsigned int flags)
  40 {
  41         const struct net_bridge *br = port->br;
  42         const struct net_device *dev = port->dev;
  43         struct ifinfomsg *hdr;
  44         struct nlmsghdr *nlh;
  45         u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
  46
  47         br_debug(br, "br_fill_info event %d port %s master %s\n",
  48                      event, dev->name, br->dev->name);
  49
  50         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
  51         if (nlh == NULL)
  52                 return -EMSGSIZE;
  53
  54         hdr = nlmsg_data(nlh);
  55         hdr->ifi_family = AF_BRIDGE;
  56         hdr->__ifi_pad = 0;
  57         hdr->ifi_type = dev->type;
  58         hdr->ifi_index = dev->ifindex;
  59         hdr->ifi_flags = dev_get_flags(dev);
  60         hdr->ifi_change = 0;
  61
  62         NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
  63         NLA_PUT_U32(skb, IFLA_MASTER, br->dev->ifindex);
  64         NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);
  65         NLA_PUT_U8(skb, IFLA_OPERSTATE, operstate);
  66
  67         if (dev->addr_len)
  68                 NLA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
  69
  70         if (dev->ifindex != dev->iflink)
  71                 NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);
  72
  73         if (event == RTM_NEWLINK)
  74                 NLA_PUT_U8(skb, IFLA_PROTINFO, port->state);
  75
  76         return nlmsg_end(skb, nlh);
  77
  78 nla_put_failure:
  79         nlmsg_cancel(skb, nlh);
  80         return -EMSGSIZE;
  81 }
  82
  83 /*
  84  * Notify listeners of a change in port information
  85  */
  86 void br_ifinfo_notify(int event, struct net_bridge_port *port)
  87 {
  88         struct net *net = dev_net(port->dev);
  89         struct sk_buff *skb;
  90         int err = -ENOBUFS;
  91
  92         br_debug(port->br, "port %u(%s) event %d\n",
  93                  (unsigned)port->port_no, port->dev->name, event);
  94
  95         skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
  96         if (skb == NULL)
  97                 goto errout;
  98
  99         err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
 100         if (err < 0) {
 101                 /* -EMSGSIZE implies BUG in br_nlmsg_size() */
 102                 WARN_ON(err == -EMSGSIZE);
 103                 kfree_skb(skb);
 104                 goto errout;
 105         }
 106         rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 107         return;
 108 errout:
 109         if (err < 0)
 110                 rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 111 }
 112
 113 /*
 114  * Dump information about all ports, in response to GETLINK
 115  */
 116 static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 117 {
 118         struct net *net = sock_net(skb->sk);
 119         struct net_device *dev;
 120         int idx;
 121
 122         idx = 0;
 123         rcu_read_lock();
 124         for_each_netdev_rcu(net, dev) {
 125                 struct net_bridge_port *port = br_port_get_rcu(dev);
 126
 127                 /* not a bridge port */
 128                 if (!port || idx < cb->args[0])
 129                         goto skip;
 130
 131                 if (br_fill_ifinfo(skb, port,
 132                                    NETLINK_CB(cb->skb).pid,
 133                                    cb->nlh->nlmsg_seq, RTM_NEWLINK,
 134                                    NLM_F_MULTI) < 0)
 135                         break;
 136 skip:
 137                 ++idx;
 138         }
 139         rcu_read_unlock();
 140         cb->args[0] = idx;
 141
 142         return skb->len;
 143 }
 144
 145 /*
 146  * Change state of port (ie from forwarding to blocking etc)
 147  * Used by spanning tree in user space.
 148  */
 149 static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 150 {
 151         struct net *net = sock_net(skb->sk);
 152         struct ifinfomsg *ifm;
 153         struct nlattr *protinfo;
 154         struct net_device *dev;
 155         struct net_bridge_port *p;
 156         u8 new_state;
 157
 158         if (nlmsg_len(nlh) < sizeof(*ifm))
 159                 return -EINVAL;
 160
 161         ifm = nlmsg_data(nlh);
 162         if (ifm->ifi_family != AF_BRIDGE)
 163                 return -EPFNOSUPPORT;
 164
 165         protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);
 166         if (!protinfo || nla_len(protinfo) < sizeof(u8))
 167                 return -EINVAL;
 168
 169         new_state = nla_get_u8(protinfo);
 170         if (new_state > BR_STATE_BLOCKING)
 171                 return -EINVAL;
 172
 173         dev = __dev_get_by_index(net, ifm->ifi_index);
 174         if (!dev)
 175                 return -ENODEV;
 176
 177         p = br_port_get_rtnl(dev);
 178         if (!p)
 179                 return -EINVAL;
 180
 181         /* if kernel STP is running, don't allow changes */
 182         if (p->br->stp_enabled == BR_KERNEL_STP)
 183                 return -EBUSY;
 184
 185         if (!netif_running(dev) ||
 186             (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED))
 187                 return -ENETDOWN;
 188
 189         p->state = new_state;
 190         br_log_state(p);
 191         br_ifinfo_notify(RTM_NEWLINK, p);
 192
 193         return 0;
 194 }
 195
 196 static int br_validate(struct nlattr *tb[], struct nlattr *data[])
 197 {
 198         if (tb[IFLA_ADDRESS]) {
 199                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
 200                         return -EINVAL;
 201                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 202                         return -EADDRNOTAVAIL;
 203         }
 204
 205         return 0;
 206 }
 207
 208 static struct rtnl_link_ops br_link_ops __read_mostly = {
 209         .kind           = "bridge",
 210         .priv_size      = sizeof(struct net_bridge),
 211         .setup          = br_dev_setup,
 212         .validate       = br_validate,
 213         .dellink        = br_dev_delete,
 214 };
 215
 216 int __init br_netlink_init(void)
 217 {
 218         int err;
 219
 220         err = rtnl_link_register(&br_link_ops);
 221         if (err < 0)
 222                 goto err1;
 223
 224         err = __rtnl_register(PF_BRIDGE, RTM_GETLINK, NULL,
 225                               br_dump_ifinfo, NULL);
 226         if (err)
 227                 goto err2;
 228         err = __rtnl_register(PF_BRIDGE, RTM_SETLINK,
 229                               br_rtm_setlink, NULL, NULL);
 230         if (err)
 231                 goto err3;
 232         err = __rtnl_register(PF_BRIDGE, RTM_NEWNEIGH,
 233                               br_fdb_add, NULL, NULL);
 234         if (err)
 235                 goto err3;
 236         err = __rtnl_register(PF_BRIDGE, RTM_DELNEIGH,
 237                               br_fdb_delete, NULL, NULL);
 238         if (err)
 239                 goto err3;
 240         err = __rtnl_register(PF_BRIDGE, RTM_GETNEIGH,
 241                               NULL, br_fdb_dump, NULL);
 242         if (err)
 243                 goto err3;
 244
 245         return 0;
 246
 247 err3:
 248         rtnl_unregister_all(PF_BRIDGE);
 249 err2:
 250         rtnl_link_unregister(&br_link_ops);
 251 err1:
 252         return err;
 253 }
 254
 255 void __exit br_netlink_fini(void)
 256 {
 257         rtnl_link_unregister(&br_link_ops);
 258         rtnl_unregister_all(PF_BRIDGE);
 259 }