net/phonet/pn_netlink.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * File: pn_netlink.c
   4  *
   5  * Phonet netlink interface
   6  *
   7  * Copyright (C) 2008 Nokia Corporation.
   8  *
   9  * Authors: Sakari Ailus <sakari.ailus@nokia.com>
  10  *          Remi Denis-Courmont
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/netlink.h>
  15 #include <linux/phonet.h>
  16 #include <linux/slab.h>
  17 #include <net/sock.h>
  18 #include <net/phonet/pn_dev.h>
  19
  20 /* Device address handling */
  21
  22 static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,
  23                      u32 portid, u32 seq, int event);
  24
  25 void phonet_address_notify(struct net *net, int event, u32 ifindex, u8 addr)
  26 {
  27         struct sk_buff *skb;
  28         int err = -ENOBUFS;
  29
  30         skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
  31                         nla_total_size(1), GFP_KERNEL);
  32         if (skb == NULL)
  33                 goto errout;
  34
  35         err = fill_addr(skb, ifindex, addr, 0, 0, event);
  36         if (err < 0) {
  37                 WARN_ON(err == -EMSGSIZE);
  38                 kfree_skb(skb);
  39                 goto errout;
  40         }
  41
  42         rtnl_notify(skb, net, 0, RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
  43         return;
  44 errout:
  45         rtnl_set_sk_err(net, RTNLGRP_PHONET_IFADDR, err);
  46 }
  47
  48 static const struct nla_policy ifa_phonet_policy[IFA_MAX+1] = {
  49         [IFA_LOCAL] = { .type = NLA_U8 },
  50 };
  51
  52 static int addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
  53                      struct netlink_ext_ack *extack)
  54 {
  55         struct net *net = sock_net(skb->sk);
  56         struct nlattr *tb[IFA_MAX+1];
  57         struct net_device *dev;
  58         struct ifaddrmsg *ifm;
  59         int err;
  60         u8 pnaddr;
  61
  62         if (!netlink_capable(skb, CAP_NET_ADMIN))
  63                 return -EPERM;
  64
  65         if (!netlink_capable(skb, CAP_SYS_ADMIN))
  66                 return -EPERM;
  67
  68         err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
  69                                      ifa_phonet_policy, extack);
  70         if (err < 0)
  71                 return err;
  72
  73         ifm = nlmsg_data(nlh);
  74         if (tb[IFA_LOCAL] == NULL)
  75                 return -EINVAL;
  76         pnaddr = nla_get_u8(tb[IFA_LOCAL]);
  77         if (pnaddr & 3)
  78                 /* Phonet addresses only have 6 high-order bits */
  79                 return -EINVAL;
  80
  81         rcu_read_lock();
  82
  83         dev = dev_get_by_index_rcu(net, ifm->ifa_index);
  84         if (!dev) {
  85                 rcu_read_unlock();
  86                 return -ENODEV;
  87         }
  88
  89         if (nlh->nlmsg_type == RTM_NEWADDR)
  90                 err = phonet_address_add(dev, pnaddr);
  91         else
  92                 err = phonet_address_del(dev, pnaddr);
  93
  94         rcu_read_unlock();
  95
  96         if (!err)
  97                 phonet_address_notify(net, nlh->nlmsg_type, ifm->ifa_index, pnaddr);
  98
  99         return err;
 100 }
 101
 102 static int fill_addr(struct sk_buff *skb, u32 ifindex, u8 addr,
 103                      u32 portid, u32 seq, int event)
 104 {
 105         struct ifaddrmsg *ifm;
 106         struct nlmsghdr *nlh;
 107
 108         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*ifm), 0);
 109         if (nlh == NULL)
 110                 return -EMSGSIZE;
 111
 112         ifm = nlmsg_data(nlh);
 113         ifm->ifa_family = AF_PHONET;
 114         ifm->ifa_prefixlen = 0;
 115         ifm->ifa_flags = IFA_F_PERMANENT;
 116         ifm->ifa_scope = RT_SCOPE_LINK;
 117         ifm->ifa_index = ifindex;
 118         if (nla_put_u8(skb, IFA_LOCAL, addr))
 119                 goto nla_put_failure;
 120         nlmsg_end(skb, nlh);
 121         return 0;
 122
 123 nla_put_failure:
 124         nlmsg_cancel(skb, nlh);
 125         return -EMSGSIZE;
 126 }
 127
 128 static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 129 {
 130         int addr_idx = 0, addr_start_idx = cb->args[1];
 131         int dev_idx = 0, dev_start_idx = cb->args[0];
 132         struct phonet_device_list *pndevs;
 133         struct phonet_device *pnd;
 134         int err = 0;
 135
 136         pndevs = phonet_device_list(sock_net(skb->sk));
 137
 138         rcu_read_lock();
 139         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
 140                 DECLARE_BITMAP(addrs, 64);
 141                 u8 addr;
 142
 143                 if (dev_idx > dev_start_idx)
 144                         addr_start_idx = 0;
 145                 if (dev_idx++ < dev_start_idx)
 146                         continue;
 147
 148                 addr_idx = 0;
 149                 memcpy(addrs, pnd->addrs, sizeof(pnd->addrs));
 150
 151                 for_each_set_bit(addr, addrs, 64) {
 152                         if (addr_idx++ < addr_start_idx)
 153                                 continue;
 154
 155                         err = fill_addr(skb, READ_ONCE(pnd->netdev->ifindex),
 156                                         addr << 2, NETLINK_CB(cb->skb).portid,
 157                                         cb->nlh->nlmsg_seq, RTM_NEWADDR);
 158                         if (err < 0)
 159                                 goto out;
 160                 }
 161         }
 162 out:
 163         rcu_read_unlock();
 164
 165         cb->args[0] = dev_idx;
 166         cb->args[1] = addr_idx;
 167
 168         return err;
 169 }
 170
 171 /* Routes handling */
 172
 173 static int fill_route(struct sk_buff *skb, u32 ifindex, 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) || nla_put_u32(skb, RTA_OIF, ifindex))
 194                 goto nla_put_failure;
 195         nlmsg_end(skb, nlh);
 196         return 0;
 197
 198 nla_put_failure:
 199         nlmsg_cancel(skb, nlh);
 200         return -EMSGSIZE;
 201 }
 202
 203 void rtm_phonet_notify(struct net *net, int event, u32 ifindex, u8 dst)
 204 {
 205         struct sk_buff *skb;
 206         int err = -ENOBUFS;
 207
 208         skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct rtmsg)) +
 209                         nla_total_size(1) + nla_total_size(4), GFP_KERNEL);
 210         if (skb == NULL)
 211                 goto errout;
 212
 213         err = fill_route(skb, ifindex, dst, 0, 0, event);
 214         if (err < 0) {
 215                 WARN_ON(err == -EMSGSIZE);
 216                 kfree_skb(skb);
 217                 goto errout;
 218         }
 219
 220         rtnl_notify(skb, net, 0, RTNLGRP_PHONET_ROUTE, NULL, GFP_KERNEL);
 221         return;
 222 errout:
 223         rtnl_set_sk_err(net, 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         bool sync_needed = false;
 237         struct net_device *dev;
 238         struct rtmsg *rtm;
 239         u32 ifindex;
 240         int err;
 241         u8 dst;
 242
 243         if (!netlink_capable(skb, CAP_NET_ADMIN))
 244                 return -EPERM;
 245
 246         if (!netlink_capable(skb, CAP_SYS_ADMIN))
 247                 return -EPERM;
 248
 249         err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
 250                                      rtm_phonet_policy, 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         ifindex = nla_get_u32(tb[RTA_OIF]);
 264
 265         rcu_read_lock();
 266
 267         dev = dev_get_by_index_rcu(net, ifindex);
 268         if (!dev) {
 269                 rcu_read_unlock();
 270                 return -ENODEV;
 271         }
 272
 273         if (nlh->nlmsg_type == RTM_NEWROUTE) {
 274                 err = phonet_route_add(dev, dst);
 275         } else {
 276                 err = phonet_route_del(dev, dst);
 277                 if (!err)
 278                         sync_needed = true;
 279         }
 280
 281         rcu_read_unlock();
 282
 283         if (sync_needed) {
 284                 synchronize_rcu();
 285                 dev_put(dev);
 286         }
 287         if (!err)
 288                 rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst);
 289
 290         return err;
 291 }
 292
 293 static int route_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 294 {
 295         struct net *net = sock_net(skb->sk);
 296         int err = 0;
 297         u8 addr;
 298
 299         rcu_read_lock();
 300         for (addr = cb->args[0]; addr < 64; addr++) {
 301                 struct net_device *dev = phonet_route_get_rcu(net, addr << 2);
 302
 303                 if (!dev)
 304                         continue;
 305
 306                 err = fill_route(skb, READ_ONCE(dev->ifindex), addr << 2,
 307                                  NETLINK_CB(cb->skb).portid,
 308                                  cb->nlh->nlmsg_seq, RTM_NEWROUTE);
 309                 if (err < 0)
 310                         break;
 311         }
 312         rcu_read_unlock();
 313         cb->args[0] = addr;
 314
 315         return err;
 316 }
 317
 318 static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_module = {
 319         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWADDR,
 320          .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
 321         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELADDR,
 322          .doit = addr_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
 323         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR,
 324          .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
 325         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE,
 326          .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
 327         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,
 328          .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
 329         {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETROUTE,
 330          .dumpit = route_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
 331 };
 332
 333 int __init phonet_netlink_register(void)
 334 {
 335         return rtnl_register_many(phonet_rtnl_msg_handlers);
 336 }