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 <net/rtnetlink.h>
  15 #include <net/net_namespace.h>
  16 #include <net/sock.h>
  17 #include "br_private.h"
  18
  19 static inline size_t br_nlmsg_size(void)
  20 {
  21         return NLMSG_ALIGN(sizeof(struct ifinfomsg))
  22                + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
  23                + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
  24                + nla_total_size(4) /* IFLA_MASTER */
  25                + nla_total_size(4) /* IFLA_MTU */
  26                + nla_total_size(4) /* IFLA_LINK */
  27                + nla_total_size(1) /* IFLA_OPERSTATE */
  28                + nla_total_size(1); /* IFLA_PROTINFO */
  29 }
  30
  31 /*
  32  * Create one netlink message for one interface
  33  * Contains port and master info as well as carrier and bridge state.
  34  */
  35 static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
  36                           u32 pid, u32 seq, int event, unsigned int flags)
  37 {
  38         const struct net_bridge *br = port->br;
  39         const struct net_device *dev = port->dev;
  40         struct ifinfomsg *hdr;
  41         struct nlmsghdr *nlh;
  42         u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
  43
  44         pr_debug("br_fill_info event %d port %s master %s\n",
  45                  event, dev->name, br->dev->name);
  46
  47         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
  48         if (nlh == NULL)
  49                 return -EMSGSIZE;
  50
  51         hdr = nlmsg_data(nlh);
  52         hdr->ifi_family = AF_BRIDGE;
  53         hdr->__ifi_pad = 0;
  54         hdr->ifi_type = dev->type;
  55         hdr->ifi_index = dev->ifindex;
  56         hdr->ifi_flags = dev_get_flags(dev);
  57         hdr->ifi_change = 0;
  58
  59         NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
  60         NLA_PUT_U32(skb, IFLA_MASTER, br->dev->ifindex);
  61         NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);
  62         NLA_PUT_U8(skb, IFLA_OPERSTATE, operstate);
  63
  64         if (dev->addr_len)
  65                 NLA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
  66
  67         if (dev->ifindex != dev->iflink)
  68                 NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);
  69
  70         if (event == RTM_NEWLINK)
  71                 NLA_PUT_U8(skb, IFLA_PROTINFO, port->state);
  72
  73         return nlmsg_end(skb, nlh);
  74
  75 nla_put_failure:
  76         nlmsg_cancel(skb, nlh);
  77         return -EMSGSIZE;
  78 }
  79
  80 /*
  81  * Notify listeners of a change in port information
  82  */
  83 void br_ifinfo_notify(int event, struct net_bridge_port *port)
  84 {
  85         struct net *net = dev_net(port->dev);
  86         struct sk_buff *skb;
  87         int err = -ENOBUFS;
  88
  89         pr_debug("bridge notify event=%d\n", event);
  90         skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
  91         if (skb == NULL)
  92                 goto errout;
  93
  94         err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
  95         if (err < 0) {
  96                 /* -EMSGSIZE implies BUG in br_nlmsg_size() */
  97                 WARN_ON(err == -EMSGSIZE);
  98                 kfree_skb(skb);
  99                 goto errout;
 100         }
 101         rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 102         return;
 103 errout:
 104         if (err < 0)
 105                 rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 106 }
 107
 108 /*
 109  * Dump information about all ports, in response to GETLINK
 110  */
 111 static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 112 {
 113         struct net *net = sock_net(skb->sk);
 114         struct net_device *dev;
 115         int idx;
 116
 117         idx = 0;
 118         for_each_netdev(net, dev) {
 119                 /* not a bridge port */
 120                 if (dev->br_port == NULL || idx < cb->args[0])
 121                         goto skip;
 122
 123                 if (br_fill_ifinfo(skb, dev->br_port, NETLINK_CB(cb->skb).pid,
 124                                    cb->nlh->nlmsg_seq, RTM_NEWLINK,
 125                                    NLM_F_MULTI) < 0)
 126                         break;
 127 skip:
 128                 ++idx;
 129         }
 130
 131         cb->args[0] = idx;
 132
 133         return skb->len;
 134 }
 135
 136 /*
 137  * Change state of port (ie from forwarding to blocking etc)
 138  * Used by spanning tree in user space.
 139  */
 140 static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 141 {
 142         struct net *net = sock_net(skb->sk);
 143         struct ifinfomsg *ifm;
 144         struct nlattr *protinfo;
 145         struct net_device *dev;
 146         struct net_bridge_port *p;
 147         u8 new_state;
 148
 149         if (nlmsg_len(nlh) < sizeof(*ifm))
 150                 return -EINVAL;
 151
 152         ifm = nlmsg_data(nlh);
 153         if (ifm->ifi_family != AF_BRIDGE)
 154                 return -EPFNOSUPPORT;
 155
 156         protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);
 157         if (!protinfo || nla_len(protinfo) < sizeof(u8))
 158                 return -EINVAL;
 159
 160         new_state = nla_get_u8(protinfo);
 161         if (new_state > BR_STATE_BLOCKING)
 162                 return -EINVAL;
 163
 164         dev = __dev_get_by_index(net, ifm->ifi_index);
 165         if (!dev)
 166                 return -ENODEV;
 167
 168         p = dev->br_port;
 169         if (!p)
 170                 return -EINVAL;
 171
 172         /* if kernel STP is running, don't allow changes */
 173         if (p->br->stp_enabled == BR_KERNEL_STP)
 174                 return -EBUSY;
 175
 176         if (!netif_running(dev) ||
 177             (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED))
 178                 return -ENETDOWN;
 179
 180         p->state = new_state;
 181         br_log_state(p);
 182         return 0;
 183 }
 184
 185
 186 int __init br_netlink_init(void)
 187 {
 188         if (__rtnl_register(PF_BRIDGE, RTM_GETLINK, NULL, br_dump_ifinfo))
 189                 return -ENOBUFS;
 190
 191         /* Only the first call to __rtnl_register can fail */
 192         __rtnl_register(PF_BRIDGE, RTM_SETLINK, br_rtm_setlink, NULL);
 193
 194         return 0;
 195 }
 196
 197 void __exit br_netlink_fini(void)
 198 {
 199         rtnl_unregister_all(PF_BRIDGE);
 200 }
 201