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 <net/rtnetlink.h>
  16 #include <net/net_namespace.h>
  17 #include <net/sock.h>
  18 #include "br_private.h"
  19
  20 static inline size_t br_nlmsg_size(void)
  21 {
  22         return NLMSG_ALIGN(sizeof(struct ifinfomsg))
  23                + nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
  24                + nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
  25                + nla_total_size(4) /* IFLA_MASTER */
  26                + nla_total_size(4) /* IFLA_MTU */
  27                + nla_total_size(4) /* IFLA_LINK */
  28                + nla_total_size(1) /* IFLA_OPERSTATE */
  29                + nla_total_size(1); /* IFLA_PROTINFO */
  30 }
  31
  32 /*
  33  * Create one netlink message for one interface
  34  * Contains port and master info as well as carrier and bridge state.
  35  */
  36 static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
  37                           u32 pid, u32 seq, int event, unsigned int flags)
  38 {
  39         const struct net_bridge *br = port->br;
  40         const struct net_device *dev = port->dev;
  41         struct ifinfomsg *hdr;
  42         struct nlmsghdr *nlh;
  43         u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
  44
  45         br_debug(br, "br_fill_info event %d port %s master %s\n",
  46                      event, dev->name, br->dev->name);
  47
  48         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*hdr), flags);
  49         if (nlh == NULL)
  50                 return -EMSGSIZE;
  51
  52         hdr = nlmsg_data(nlh);
  53         hdr->ifi_family = AF_BRIDGE;
  54         hdr->__ifi_pad = 0;
  55         hdr->ifi_type = dev->type;
  56         hdr->ifi_index = dev->ifindex;
  57         hdr->ifi_flags = dev_get_flags(dev);
  58         hdr->ifi_change = 0;
  59
  60         NLA_PUT_STRING(skb, IFLA_IFNAME, dev->name);
  61         NLA_PUT_U32(skb, IFLA_MASTER, br->dev->ifindex);
  62         NLA_PUT_U32(skb, IFLA_MTU, dev->mtu);
  63         NLA_PUT_U8(skb, IFLA_OPERSTATE, operstate);
  64
  65         if (dev->addr_len)
  66                 NLA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
  67
  68         if (dev->ifindex != dev->iflink)
  69                 NLA_PUT_U32(skb, IFLA_LINK, dev->iflink);
  70
  71         if (event == RTM_NEWLINK)
  72                 NLA_PUT_U8(skb, IFLA_PROTINFO, port->state);
  73
  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)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         for_each_netdev(net, dev) {
 122                 /* not a bridge port */
 123                 if (!br_port_exists(dev) || idx < cb->args[0])
 124                         goto skip;
 125
 126                 if (br_fill_ifinfo(skb, br_port_get(dev),
 127                                    NETLINK_CB(cb->skb).pid,
 128                                    cb->nlh->nlmsg_seq, RTM_NEWLINK,
 129                                    NLM_F_MULTI) < 0)
 130                         break;
 131 skip:
 132                 ++idx;
 133         }
 134
 135         cb->args[0] = idx;
 136
 137         return skb->len;
 138 }
 139
 140 /*
 141  * Change state of port (ie from forwarding to blocking etc)
 142  * Used by spanning tree in user space.
 143  */
 144 static int br_rtm_setlink(struct sk_buff *skb,  struct nlmsghdr *nlh, void *arg)
 145 {
 146         struct net *net = sock_net(skb->sk);
 147         struct ifinfomsg *ifm;
 148         struct nlattr *protinfo;
 149         struct net_device *dev;
 150         struct net_bridge_port *p;
 151         u8 new_state;
 152
 153         if (nlmsg_len(nlh) < sizeof(*ifm))
 154                 return -EINVAL;
 155
 156         ifm = nlmsg_data(nlh);
 157         if (ifm->ifi_family != AF_BRIDGE)
 158                 return -EPFNOSUPPORT;
 159
 160         protinfo = nlmsg_find_attr(nlh, sizeof(*ifm), IFLA_PROTINFO);
 161         if (!protinfo || nla_len(protinfo) < sizeof(u8))
 162                 return -EINVAL;
 163
 164         new_state = nla_get_u8(protinfo);
 165         if (new_state > BR_STATE_BLOCKING)
 166                 return -EINVAL;
 167
 168         dev = __dev_get_by_index(net, ifm->ifi_index);
 169         if (!dev)
 170                 return -ENODEV;
 171
 172         if (!br_port_exists(dev))
 173                 return -EINVAL;
 174         p = br_port_get(dev);
 175
 176         /* if kernel STP is running, don't allow changes */
 177         if (p->br->stp_enabled == BR_KERNEL_STP)
 178                 return -EBUSY;
 179
 180         if (!netif_running(dev) ||
 181             (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED))
 182                 return -ENETDOWN;
 183
 184         p->state = new_state;
 185         br_log_state(p);
 186         return 0;
 187 }
 188
 189
 190 int __init br_netlink_init(void)
 191 {
 192         if (__rtnl_register(PF_BRIDGE, RTM_GETLINK, NULL, br_dump_ifinfo))
 193                 return -ENOBUFS;
 194
 195         /* Only the first call to __rtnl_register can fail */
 196         __rtnl_register(PF_BRIDGE, RTM_SETLINK, br_rtm_setlink, NULL);
 197
 198         return 0;
 199 }
 200
 201 void __exit br_netlink_fini(void)
 202 {
 203         rtnl_unregister_all(PF_BRIDGE);
 204 }
 205