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