net/phonet/pn_netlink.c

   1 /*
   2  * File: pn_netlink.c
   3  *
   4  * Phonet netlink interface
   5  *
   6  * Copyright (C) 2008 Nokia Corporation.
   7  *
   8  * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
   9  * Original author: Sakari Ailus <sakari.ailus@nokia.com>
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * version 2 as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  23  * 02110-1301 USA
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/netlink.h>
  28 #include <linux/phonet.h>
  29 #include <net/sock.h>
  30 #include <net/phonet/pn_dev.h>
  31
  32 static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
  33                      u32 pid, u32 seq, int event);
  34
  35 static void rtmsg_notify(int event, struct net_device *dev, u8 addr)
  36 {
  37         struct sk_buff *skb;
  38         int err = -ENOBUFS;
  39
  40         skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
  41                         nla_total_size(1), GFP_KERNEL);
  42         if (skb == NULL)
  43                 goto errout;
  44         err = fill_addr(skb, dev, addr, 0, 0, event);
  45         if (err < 0) {
  46                 WARN_ON(err == -EMSGSIZE);
  47                 kfree_skb(skb);
  48                 goto errout;
  49         }
  50         rtnl_notify(skb, dev_net(dev), 0,
  51                     RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
  52         return;
  53 errout:
  54         if (err < 0)
  55                 rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
  56 }
  57
  58 static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
  59         [IFA_LOCAL] = { .type = NLA_U8 },
  60 };
  61
  62 static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *attr)
  63 {
  64         struct net *net = sock_net(skb->sk);
  65         struct nlattr *tb[IFA_MAX+1];
  66         struct net_device *dev;
  67         struct ifaddrmsg *ifm;
  68         int err;
  69         u8 pnaddr;
  70
  71         if (!capable(CAP_SYS_ADMIN))
  72                 return -EPERM;
  73
  74         ASSERT_RTNL();
  75
  76         err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_phonet_policy);
  77         if (err < 0)
  78                 return err;
  79
  80         ifm = nlmsg_data(nlh);
  81         if (tb[IFA_LOCAL] == NULL)
  82                 return -EINVAL;
  83         pnaddr = nla_get_u8(tb[IFA_LOCAL]);
  84         if (pnaddr & 3)
  85                 /* Phonet addresses only have 6 high-order bits */
  86                 return -EINVAL;
  87
  88         dev = __dev_get_by_index(net, ifm->ifa_index);
  89         if (dev == NULL)
  90                 return -ENODEV;
  91
  92         if (nlh->nlmsg_type == RTM_NEWADDR)
  93                 err = phonet_address_add(dev, pnaddr);
  94         else
  95                 err = phonet_address_del(dev, pnaddr);
  96         if (!err)
  97                 rtmsg_notify(nlh->nlmsg_type, dev, pnaddr);
  98         return err;
  99 }
 100
 101 static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
 102                         u32 pid, u32 seq, int event)
 103 {
 104         struct ifaddrmsg *ifm;
 105         struct nlmsghdr *nlh;
 106
 107         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*ifm), 0);
 108         if (nlh == NULL)
 109                 return -EMSGSIZE;
 110
 111         ifm = nlmsg_data(nlh);
 112         ifm->ifa_family = AF_PHONET;
 113         ifm->ifa_prefixlen = 0;
 114         ifm->ifa_flags = IFA_F_PERMANENT;
 115         ifm->ifa_scope = RT_SCOPE_LINK;
 116         ifm->ifa_index = dev->ifindex;
 117         NLA_PUT_U8(skb, IFA_LOCAL, addr);
 118         return nlmsg_end(skb, nlh);
 119
 120 nla_put_failure:
 121         nlmsg_cancel(skb, nlh);
 122         return -EMSGSIZE;
 123 }
 124
 125 static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 126 {
 127         struct phonet_device_list *pndevs;
 128         struct phonet_device *pnd;
 129         int dev_idx = 0, dev_start_idx = cb->args[0];
 130         int addr_idx = 0, addr_start_idx = cb->args[1];
 131
 132         pndevs = phonet_device_list(sock_net(skb->sk));
 133         spin_lock_bh(&pndevs->lock);
 134         list_for_each_entry(pnd, &pndevs->list, list) {
 135                 u8 addr;
 136
 137                 if (dev_idx > dev_start_idx)
 138                         addr_start_idx = 0;
 139                 if (dev_idx++ < dev_start_idx)
 140                         continue;
 141
 142                 addr_idx = 0;
 143                 for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
 144                         addr = find_next_bit(pnd->addrs, 64, 1+addr)) {
 145                         if (addr_idx++ < addr_start_idx)
 146                                 continue;
 147
 148                         if (fill_addr(skb, pnd->netdev, addr << 2,
 149                                          NETLINK_CB(cb->skb).pid,
 150                                         cb->nlh->nlmsg_seq, RTM_NEWADDR))
 151                                 goto out;
 152                 }
 153         }
 154
 155 out:
 156         spin_unlock_bh(&pndevs->lock);
 157         cb->args[0] = dev_idx;
 158         cb->args[1] = addr_idx;
 159
 160         return skb->len;
 161 }
 162
 163 int __init phonet_netlink_register(void)
 164 {
 165         int err = __rtnl_register(PF_PHONET, RTM_NEWADDR, addr_doit, NULL);
 166         if (err)
 167                 return err;
 168
 169         /* Further __rtnl_register() cannot fail */
 170         __rtnl_register(PF_PHONET, RTM_DELADDR, addr_doit, NULL);
 171         __rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit);
 172         return 0;
 173 }