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  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
   9  *          Remi Denis-Courmont
  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 <linux/slab.h>
  30 #include <net/sock.h>
  31 #include <net/phonet/pn_dev.h>
  32
  33 /* Device address handling */
  34
  35 static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
  36                      u32 portid, u32 seq, int event);
  37
  38 void phonet_address_notify(int event, struct net_device *dev, u8 addr)
  39 {
  40         struct sk_buff *skb;
  41         int err = -ENOBUFS;
  42
  43         skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
  44                         nla_total_size(1), GFP_KERNEL);
  45         if (skb == NULL)
  46                 goto errout;
  47         err = fill_addr(skb, dev, addr, 0, 0, event);
  48         if (err < 0) {
  49                 WARN_ON(err == -EMSGSIZE);
  50                 kfree_skb(skb);
  51                 goto errout;
  52         }
  53         rtnl_notify(skb, dev_net(dev), 0,
  54                     RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
  55         return;
  56 errout:
  57         rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
  58 }
  59
  60 static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
  61         [IFA_LOCAL] = { .type = NLA_U8 },
  62 };
  63
  64 static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
  65                      struct netlink_ext_ack *extack)
  66 {
  67         struct net *net = sock_net(skb->sk);
  68         struct nlattr *tb[IFA_MAX+1];
  69         struct net_device *dev;
  70         struct ifaddrmsg *ifm;
  71         int err;
  72         u8 pnaddr;
  73
  74         if (!netlink_capable(skb, CAP_NET_ADMIN))
  75                 return -EPERM;
  76
  77         if (!netlink_capable(skb, CAP_SYS_ADMIN))
  78                 return -EPERM;
  79
  80         ASSERT_RTNL();
  81
  82         err = nlmsg_parse(nlh, sizeof(*ifm), tb, IFA_MAX, ifa_phonet_policy,
  83                           extack);
  84         if (err < 0)
  85                 return err;
  86
  87         ifm = nlmsg_data(nlh);
  88         if (tb[IFA_LOCAL] == NULL)
  89                 return -EINVAL;
  90         pnaddr = nla_get_u8(tb[IFA_LOCAL]);
  91         if (pnaddr & 3)
  92                 /* Phonet addresses only have 6 high-order bits */
  93                 return -EINVAL;
  94
  95         dev = __dev_get_by_index(net, ifm->ifa_index);
  96         if (dev == NULL)
  97                 return -ENODEV;
  98
  99         if (nlh->nlmsg_type == RTM_NEWADDR)
 100                 err = phonet_address_add(dev, pnaddr);
 101         else
 102                 err = phonet_address_del(dev, pnaddr);
 103         if (!err)
 104                 phonet_address_notify(nlh->nlmsg_type, dev, pnaddr);
 105         return err;
 106 }
 107
 108 static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
 109                         u32 portid, u32 seq, int event)
 110 {
 111         struct ifaddrmsg *ifm;
 112         struct nlmsghdr *nlh;
 113
 114         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), 0);
 115         if (nlh == NULL)
 116                 return -EMSGSIZE;
 117
 118         ifm = nlmsg_data(nlh);
 119         ifm->ifa_family = AF_PHONET;
 120         ifm->ifa_prefixlen = 0;
 121         ifm->ifa_flags = IFA_F_PERMANENT;
 122         ifm->ifa_scope = RT_SCOPE_LINK;
 123         ifm->ifa_index = dev->ifindex;
 124         if (nla_put_u8(skb, IFA_LOCAL, addr))
 125                 goto nla_put_failure;
 126         nlmsg_end(skb, nlh);
 127         return 0;
 128
 129 nla_put_failure:
 130         nlmsg_cancel(skb, nlh);
 131         return -EMSGSIZE;
 132 }
 133
 134 static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 135 {
 136         struct phonet_device_list *pndevs;
 137         struct phonet_device *pnd;
 138         int dev_idx = 0, dev_start_idx = cb->args[0];
 139         int addr_idx = 0, addr_start_idx = cb->args[1];
 140
 141         pndevs = phonet_device_list(sock_net(skb->sk));
 142         rcu_read_lock();
 143         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 144                 u8 addr;
 145
 146                 if (dev_idx > dev_start_idx)
 147                         addr_start_idx = 0;
 148                 if (dev_idx++ < dev_start_idx)
 149                         continue;
 150
 151                 addr_idx = 0;
 152                 for_each_set_bit(addr, pnd->addrs, 64) {
 153                         if (addr_idx++ < addr_start_idx)
 154                                 continue;
 155
 156                         if (fill_addr(skb, pnd->netdev, addr << 2,
 157                                          NETLINK_CB(cb->skb).portid,
 158                                         cb->nlh->nlmsg_seq, RTM_NEWADDR) < 0)
 159                                 goto out;
 160                 }
 161         }
 162
 163 out:
 164         rcu_read_unlock();
 165         cb->args[0] = dev_idx;
 166         cb->args[1] = addr_idx;
 167
 168         return skb->len;
 169 }
 170
 171 /* Routes handling */
 172
 173 static int fill_route(struct sk_buff *skb, struct net_device *dev, u8 dst,
 174                         u32 portid, u32 seq, int event)
 175 {
 176         struct rtmsg *rtm;
 177         struct nlmsghdr *nlh;
 178
 179         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), 0);
 180         if (nlh == NULL)
 181                 return -EMSGSIZE;
 182
 183         rtm = nlmsg_data(nlh);
 184         rtm->rtm_family = AF_PHONET;
 185         rtm->rtm_dst_len = 6;
 186         rtm->rtm_src_len = 0;
 187         rtm->rtm_tos = 0;
 188         rtm->rtm_table = RT_TABLE_MAIN;
 189         rtm->rtm_protocol = RTPROT_STATIC;
 190         rtm->rtm_scope = RT_SCOPE_UNIVERSE;
 191         rtm->rtm_type = RTN_UNICAST;
 192         rtm->rtm_flags = 0;
 193         if (nla_put_u8(skb, RTA_DST, dst) ||
 194             nla_put_u32(skb, RTA_OIF, dev->ifindex))
 195                 goto nla_put_failure;
 196         nlmsg_end(skb, nlh);
 197         return 0;
 198
 199 nla_put_failure:
 200         nlmsg_cancel(skb, nlh);
 201         return -EMSGSIZE;
 202 }
 203
 204 void rtm_phonet_notify(int event, struct net_device *dev, u8 dst)
 205 {
 206         struct sk_buff *skb;
 207         int err = -ENOBUFS;
 208
 209         skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
 210                         nla_total_size(1) + nla_total_size(4), GFP_KERNEL);
 211         if (skb == NULL)
 212                 goto errout;
 213         err = fill_route(skb, dev, dst, 0, 0, event);
 214         if (err < 0) {
 215                 WARN_ON(err == -EMSGSIZE);
 216                 kfree_skb(skb);
 217                 goto errout;
 218         }
 219         rtnl_notify(skb, dev_net(dev), 0,
 220                           RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);
 221         return;
 222 errout:
 223         rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_ROUTE, err);
 224 }
 225
 226 static const struct nla_policy rtm_phonet_policy[RTA_MAX+1] = {
 227         [RTA_DST] = { .type = NLA_U8 },
 228         [RTA_OIF] = { .type = NLA_U32 },
 229 };
 230
 231 static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
 232                       struct netlink_ext_ack *extack)
 233 {
 234         struct net *net = sock_net(skb->sk);
 235         struct nlattr *tb[RTA_MAX+1];
 236         struct net_device *dev;
 237         struct rtmsg *rtm;
 238         int err;
 239         u8 dst;
 240
 241         if (!netlink_capable(skb, CAP_NET_ADMIN))
 242                 return -EPERM;
 243
 244         if (!netlink_capable(skb, CAP_SYS_ADMIN))
 245                 return -EPERM;
 246
 247         ASSERT_RTNL();
 248
 249         err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_phonet_policy,
 250                           extack);
 251         if (err < 0)
 252                 return err;
 253
 254         rtm = nlmsg_data(nlh);
 255         if (rtm->rtm_table != RT_TABLE_MAIN || rtm->rtm_type != RTN_UNICAST)
 256                 return -EINVAL;
 257         if (tb[RTA_DST] == NULL || tb[RTA_OIF] == NULL)
 258                 return -EINVAL;
 259         dst = nla_get_u8(tb[RTA_DST]);
 260         if (dst & 3) /* Phonet addresses only have 6 high-order bits */
 261                 return -EINVAL;
 262
 263         dev = __dev_get_by_index(net, nla_get_u32(tb[RTA_OIF]));
 264         if (dev == NULL)
 265                 return -ENODEV;
 266
 267         if (nlh->nlmsg_type == RTM_NEWROUTE)
 268                 err = phonet_route_add(dev, dst);
 269         else
 270                 err = phonet_route_del(dev, dst);
 271         if (!err)
 272                 rtm_phonet_notify(nlh->nlmsg_type, dev, dst);
 273         return err;
 274 }
 275
 276 static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 277 {
 278         struct net *net = sock_net(skb->sk);
 279         u8 addr;
 280
 281         rcu_read_lock();
 282         for (addr = cb->args[0]; addr < 64; addr++) {
 283                 struct net_device *dev = phonet_route_get_rcu(net, addr << 2);
 284
 285                 if (!dev)
 286                         continue;
 287
 288                 if (fill_route(skb, dev, addr << 2, NETLINK_CB(cb->skb).portid,
 289                                cb->nlh->nlmsg_seq, RTM_NEWROUTE) < 0)
 290                         goto out;
 291         }
 292
 293 out:
 294         rcu_read_unlock();
 295         cb->args[0] = addr;
 296
 297         return skb->len;
 298 }
 299
 300 int __init phonet_netlink_register(void)
 301 {
 302         int err = __rtnl_register(PF_PHONET, RTM_NEWADDR, addr_doit,
 303                                   NULL, NULL);
 304         if (err)
 305                 return err;
 306
 307         /* Further __rtnl_register() cannot fail */
 308         __rtnl_register(PF_PHONET, RTM_DELADDR, addr_doit, NULL, NULL);
 309         __rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit, NULL);
 310         __rtnl_register(PF_PHONET, RTM_NEWROUTE, route_doit, NULL, NULL);
 311         __rtnl_register(PF_PHONET, RTM_DELROUTE, route_doit, NULL, NULL);
 312         __rtnl_register(PF_PHONET, RTM_GETROUTE, NULL, route_dumpit, NULL);
 313         return 0;
 314 }