net/core/sock_diag.c

   1 #include <linux/mutex.h>
   2 #include <linux/socket.h>
   3 #include <linux/skbuff.h>
   4 #include <net/netlink.h>
   5 #include <net/net_namespace.h>
   6 #include <linux/module.h>
   7 #include <net/sock.h>
   8 #include <linux/kernel.h>
   9 #include <linux/tcp.h>
  10 #include <linux/workqueue.h>
  11
  12 #include <linux/inet_diag.h>
  13 #include <linux/sock_diag.h>
  14
  15 static const struct sock_diag_handler *sock_diag_handlers[AF_MAX];
  16 static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
  17 static DEFINE_MUTEX(sock_diag_table_mutex);
  18 static struct workqueue_struct *broadcast_wq;
  19
  20 static u64 sock_gen_cookie(struct sock *sk)
  21 {
  22         while (1) {
  23                 u64 res = atomic64_read(&sk->sk_cookie);
  24
  25                 if (res)
  26                         return res;
  27                 res = atomic64_inc_return(&sock_net(sk)->cookie_gen);
  28                 atomic64_cmpxchg(&sk->sk_cookie, 0, res);
  29         }
  30 }
  31
  32 int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie)
  33 {
  34         u64 res;
  35
  36         if (cookie[0] == INET_DIAG_NOCOOKIE && cookie[1] == INET_DIAG_NOCOOKIE)
  37                 return 0;
  38
  39         res = sock_gen_cookie(sk);
  40         if ((u32)res != cookie[0] || (u32)(res >> 32) != cookie[1])
  41                 return -ESTALE;
  42
  43         return 0;
  44 }
  45 EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
  46
  47 void sock_diag_save_cookie(struct sock *sk, __u32 *cookie)
  48 {
  49         u64 res = sock_gen_cookie(sk);
  50
  51         cookie[0] = (u32)res;
  52         cookie[1] = (u32)(res >> 32);
  53 }
  54 EXPORT_SYMBOL_GPL(sock_diag_save_cookie);
  55
  56 int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
  57 {
  58         u32 mem[SK_MEMINFO_VARS];
  59
  60         mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
  61         mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
  62         mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
  63         mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
  64         mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
  65         mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
  66         mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
  67         mem[SK_MEMINFO_BACKLOG] = sk->sk_backlog.len;
  68
  69         return nla_put(skb, attrtype, sizeof(mem), &mem);
  70 }
  71 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
  72
  73 int sock_diag_put_filterinfo(bool may_report_filterinfo, struct sock *sk,
  74                              struct sk_buff *skb, int attrtype)
  75 {
  76         struct sock_fprog_kern *fprog;
  77         struct sk_filter *filter;
  78         struct nlattr *attr;
  79         unsigned int flen;
  80         int err = 0;
  81
  82         if (!may_report_filterinfo) {
  83                 nla_reserve(skb, attrtype, 0);
  84                 return 0;
  85         }
  86
  87         rcu_read_lock();
  88         filter = rcu_dereference(sk->sk_filter);
  89         if (!filter)
  90                 goto out;
  91
  92         fprog = filter->prog->orig_prog;
  93         if (!fprog)
  94                 goto out;
  95
  96         flen = bpf_classic_proglen(fprog);
  97
  98         attr = nla_reserve(skb, attrtype, flen);
  99         if (attr == NULL) {
 100                 err = -EMSGSIZE;
 101                 goto out;
 102         }
 103
 104         memcpy(nla_data(attr), fprog->filter, flen);
 105 out:
 106         rcu_read_unlock();
 107         return err;
 108 }
 109 EXPORT_SYMBOL(sock_diag_put_filterinfo);
 110
 111 struct broadcast_sk {
 112         struct sock *sk;
 113         struct work_struct work;
 114 };
 115
 116 static size_t sock_diag_nlmsg_size(void)
 117 {
 118         return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
 119                + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
 120                + nla_total_size(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
 121 }
 122
 123 static void sock_diag_broadcast_destroy_work(struct work_struct *work)
 124 {
 125         struct broadcast_sk *bsk =
 126                 container_of(work, struct broadcast_sk, work);
 127         struct sock *sk = bsk->sk;
 128         const struct sock_diag_handler *hndl;
 129         struct sk_buff *skb;
 130         const enum sknetlink_groups group = sock_diag_destroy_group(sk);
 131         int err = -1;
 132
 133         WARN_ON(group == SKNLGRP_NONE);
 134
 135         skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
 136         if (!skb)
 137                 goto out;
 138
 139         mutex_lock(&sock_diag_table_mutex);
 140         hndl = sock_diag_handlers[sk->sk_family];
 141         if (hndl && hndl->get_info)
 142                 err = hndl->get_info(skb, sk);
 143         mutex_unlock(&sock_diag_table_mutex);
 144
 145         if (!err)
 146                 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
 147                                 GFP_KERNEL);
 148         else
 149                 kfree_skb(skb);
 150 out:
 151         sk_destruct(sk);
 152         kfree(bsk);
 153 }
 154
 155 void sock_diag_broadcast_destroy(struct sock *sk)
 156 {
 157         /* Note, this function is often called from an interrupt context. */
 158         struct broadcast_sk *bsk =
 159                 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
 160         if (!bsk)
 161                 return sk_destruct(sk);
 162         bsk->sk = sk;
 163         INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
 164         queue_work(broadcast_wq, &bsk->work);
 165 }
 166
 167 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 168 {
 169         mutex_lock(&sock_diag_table_mutex);
 170         inet_rcv_compat = fn;
 171         mutex_unlock(&sock_diag_table_mutex);
 172 }
 173 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
 174
 175 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 176 {
 177         mutex_lock(&sock_diag_table_mutex);
 178         inet_rcv_compat = NULL;
 179         mutex_unlock(&sock_diag_table_mutex);
 180 }
 181 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
 182
 183 int sock_diag_register(const struct sock_diag_handler *hndl)
 184 {
 185         int err = 0;
 186
 187         if (hndl->family >= AF_MAX)
 188                 return -EINVAL;
 189
 190         mutex_lock(&sock_diag_table_mutex);
 191         if (sock_diag_handlers[hndl->family])
 192                 err = -EBUSY;
 193         else
 194                 sock_diag_handlers[hndl->family] = hndl;
 195         mutex_unlock(&sock_diag_table_mutex);
 196
 197         return err;
 198 }
 199 EXPORT_SYMBOL_GPL(sock_diag_register);
 200
 201 void sock_diag_unregister(const struct sock_diag_handler *hnld)
 202 {
 203         int family = hnld->family;
 204
 205         if (family >= AF_MAX)
 206                 return;
 207
 208         mutex_lock(&sock_diag_table_mutex);
 209         BUG_ON(sock_diag_handlers[family] != hnld);
 210         sock_diag_handlers[family] = NULL;
 211         mutex_unlock(&sock_diag_table_mutex);
 212 }
 213 EXPORT_SYMBOL_GPL(sock_diag_unregister);
 214
 215 static int __sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 216 {
 217         int err;
 218         struct sock_diag_req *req = nlmsg_data(nlh);
 219         const struct sock_diag_handler *hndl;
 220
 221         if (nlmsg_len(nlh) < sizeof(*req))
 222                 return -EINVAL;
 223
 224         if (req->sdiag_family >= AF_MAX)
 225                 return -EINVAL;
 226
 227         if (sock_diag_handlers[req->sdiag_family] == NULL)
 228                 request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 229                                 NETLINK_SOCK_DIAG, req->sdiag_family);
 230
 231         mutex_lock(&sock_diag_table_mutex);
 232         hndl = sock_diag_handlers[req->sdiag_family];
 233         if (hndl == NULL)
 234                 err = -ENOENT;
 235         else
 236                 err = hndl->dump(skb, nlh);
 237         mutex_unlock(&sock_diag_table_mutex);
 238
 239         return err;
 240 }
 241
 242 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 243 {
 244         int ret;
 245
 246         switch (nlh->nlmsg_type) {
 247         case TCPDIAG_GETSOCK:
 248         case DCCPDIAG_GETSOCK:
 249                 if (inet_rcv_compat == NULL)
 250                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 251                                         NETLINK_SOCK_DIAG, AF_INET);
 252
 253                 mutex_lock(&sock_diag_table_mutex);
 254                 if (inet_rcv_compat != NULL)
 255                         ret = inet_rcv_compat(skb, nlh);
 256                 else
 257                         ret = -EOPNOTSUPP;
 258                 mutex_unlock(&sock_diag_table_mutex);
 259
 260                 return ret;
 261         case SOCK_DIAG_BY_FAMILY:
 262                 return __sock_diag_rcv_msg(skb, nlh);
 263         default:
 264                 return -EINVAL;
 265         }
 266 }
 267
 268 static DEFINE_MUTEX(sock_diag_mutex);
 269
 270 static void sock_diag_rcv(struct sk_buff *skb)
 271 {
 272         mutex_lock(&sock_diag_mutex);
 273         netlink_rcv_skb(skb, &sock_diag_rcv_msg);
 274         mutex_unlock(&sock_diag_mutex);
 275 }
 276
 277 static int sock_diag_bind(struct net *net, int group)
 278 {
 279         switch (group) {
 280         case SKNLGRP_INET_TCP_DESTROY:
 281         case SKNLGRP_INET_UDP_DESTROY:
 282                 if (!sock_diag_handlers[AF_INET])
 283                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 284                                        NETLINK_SOCK_DIAG, AF_INET);
 285                 break;
 286         case SKNLGRP_INET6_TCP_DESTROY:
 287         case SKNLGRP_INET6_UDP_DESTROY:
 288                 if (!sock_diag_handlers[AF_INET6])
 289                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 290                                        NETLINK_SOCK_DIAG, AF_INET);
 291                 break;
 292         }
 293         return 0;
 294 }
 295
 296 static int __net_init diag_net_init(struct net *net)
 297 {
 298         struct netlink_kernel_cfg cfg = {
 299                 .groups = SKNLGRP_MAX,
 300                 .input  = sock_diag_rcv,
 301                 .bind   = sock_diag_bind,
 302                 .flags  = NL_CFG_F_NONROOT_RECV,
 303         };
 304
 305         net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
 306         return net->diag_nlsk == NULL ? -ENOMEM : 0;
 307 }
 308
 309 static void __net_exit diag_net_exit(struct net *net)
 310 {
 311         netlink_kernel_release(net->diag_nlsk);
 312         net->diag_nlsk = NULL;
 313 }
 314
 315 static struct pernet_operations diag_net_ops = {
 316         .init = diag_net_init,
 317         .exit = diag_net_exit,
 318 };
 319
 320 static int __init sock_diag_init(void)
 321 {
 322         broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
 323         BUG_ON(!broadcast_wq);
 324         return register_pernet_subsys(&diag_net_ops);
 325 }
 326
 327 static void __exit sock_diag_exit(void)
 328 {
 329         unregister_pernet_subsys(&diag_net_ops);
 330         destroy_workqueue(broadcast_wq);
 331 }
 332
 333 module_init(sock_diag_init);
 334 module_exit(sock_diag_exit);
 335 MODULE_LICENSE("GPL");
 336 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_SOCK_DIAG);