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         flen = bpf_classic_proglen(fprog);
  94
  95         attr = nla_reserve(skb, attrtype, flen);
  96         if (attr == NULL) {
  97                 err = -EMSGSIZE;
  98                 goto out;
  99         }
 100
 101         memcpy(nla_data(attr), fprog->filter, flen);
 102 out:
 103         rcu_read_unlock();
 104         return err;
 105 }
 106 EXPORT_SYMBOL(sock_diag_put_filterinfo);
 107
 108 struct broadcast_sk {
 109         struct sock *sk;
 110         struct work_struct work;
 111 };
 112
 113 static size_t sock_diag_nlmsg_size(void)
 114 {
 115         return NLMSG_ALIGN(sizeof(struct inet_diag_msg)
 116                + nla_total_size(sizeof(u8)) /* INET_DIAG_PROTOCOL */
 117                + nla_total_size(sizeof(struct tcp_info))); /* INET_DIAG_INFO */
 118 }
 119
 120 static void sock_diag_broadcast_destroy_work(struct work_struct *work)
 121 {
 122         struct broadcast_sk *bsk =
 123                 container_of(work, struct broadcast_sk, work);
 124         struct sock *sk = bsk->sk;
 125         const struct sock_diag_handler *hndl;
 126         struct sk_buff *skb;
 127         const enum sknetlink_groups group = sock_diag_destroy_group(sk);
 128         int err = -1;
 129
 130         WARN_ON(group == SKNLGRP_NONE);
 131
 132         skb = nlmsg_new(sock_diag_nlmsg_size(), GFP_KERNEL);
 133         if (!skb)
 134                 goto out;
 135
 136         mutex_lock(&sock_diag_table_mutex);
 137         hndl = sock_diag_handlers[sk->sk_family];
 138         if (hndl && hndl->get_info)
 139                 err = hndl->get_info(skb, sk);
 140         mutex_unlock(&sock_diag_table_mutex);
 141
 142         if (!err)
 143                 nlmsg_multicast(sock_net(sk)->diag_nlsk, skb, 0, group,
 144                                 GFP_KERNEL);
 145         else
 146                 kfree_skb(skb);
 147 out:
 148         sk_destruct(sk);
 149         kfree(bsk);
 150 }
 151
 152 void sock_diag_broadcast_destroy(struct sock *sk)
 153 {
 154         /* Note, this function is often called from an interrupt context. */
 155         struct broadcast_sk *bsk =
 156                 kmalloc(sizeof(struct broadcast_sk), GFP_ATOMIC);
 157         if (!bsk)
 158                 return sk_destruct(sk);
 159         bsk->sk = sk;
 160         INIT_WORK(&bsk->work, sock_diag_broadcast_destroy_work);
 161         queue_work(broadcast_wq, &bsk->work);
 162 }
 163
 164 void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 165 {
 166         mutex_lock(&sock_diag_table_mutex);
 167         inet_rcv_compat = fn;
 168         mutex_unlock(&sock_diag_table_mutex);
 169 }
 170 EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
 171
 172 void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
 173 {
 174         mutex_lock(&sock_diag_table_mutex);
 175         inet_rcv_compat = NULL;
 176         mutex_unlock(&sock_diag_table_mutex);
 177 }
 178 EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
 179
 180 int sock_diag_register(const struct sock_diag_handler *hndl)
 181 {
 182         int err = 0;
 183
 184         if (hndl->family >= AF_MAX)
 185                 return -EINVAL;
 186
 187         mutex_lock(&sock_diag_table_mutex);
 188         if (sock_diag_handlers[hndl->family])
 189                 err = -EBUSY;
 190         else
 191                 sock_diag_handlers[hndl->family] = hndl;
 192         mutex_unlock(&sock_diag_table_mutex);
 193
 194         return err;
 195 }
 196 EXPORT_SYMBOL_GPL(sock_diag_register);
 197
 198 void sock_diag_unregister(const struct sock_diag_handler *hnld)
 199 {
 200         int family = hnld->family;
 201
 202         if (family >= AF_MAX)
 203                 return;
 204
 205         mutex_lock(&sock_diag_table_mutex);
 206         BUG_ON(sock_diag_handlers[family] != hnld);
 207         sock_diag_handlers[family] = NULL;
 208         mutex_unlock(&sock_diag_table_mutex);
 209 }
 210 EXPORT_SYMBOL_GPL(sock_diag_unregister);
 211
 212 static int __sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 213 {
 214         int err;
 215         struct sock_diag_req *req = nlmsg_data(nlh);
 216         const struct sock_diag_handler *hndl;
 217
 218         if (nlmsg_len(nlh) < sizeof(*req))
 219                 return -EINVAL;
 220
 221         if (req->sdiag_family >= AF_MAX)
 222                 return -EINVAL;
 223
 224         if (sock_diag_handlers[req->sdiag_family] == NULL)
 225                 request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 226                                 NETLINK_SOCK_DIAG, req->sdiag_family);
 227
 228         mutex_lock(&sock_diag_table_mutex);
 229         hndl = sock_diag_handlers[req->sdiag_family];
 230         if (hndl == NULL)
 231                 err = -ENOENT;
 232         else
 233                 err = hndl->dump(skb, nlh);
 234         mutex_unlock(&sock_diag_table_mutex);
 235
 236         return err;
 237 }
 238
 239 static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 240 {
 241         int ret;
 242
 243         switch (nlh->nlmsg_type) {
 244         case TCPDIAG_GETSOCK:
 245         case DCCPDIAG_GETSOCK:
 246                 if (inet_rcv_compat == NULL)
 247                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 248                                         NETLINK_SOCK_DIAG, AF_INET);
 249
 250                 mutex_lock(&sock_diag_table_mutex);
 251                 if (inet_rcv_compat != NULL)
 252                         ret = inet_rcv_compat(skb, nlh);
 253                 else
 254                         ret = -EOPNOTSUPP;
 255                 mutex_unlock(&sock_diag_table_mutex);
 256
 257                 return ret;
 258         case SOCK_DIAG_BY_FAMILY:
 259                 return __sock_diag_rcv_msg(skb, nlh);
 260         default:
 261                 return -EINVAL;
 262         }
 263 }
 264
 265 static DEFINE_MUTEX(sock_diag_mutex);
 266
 267 static void sock_diag_rcv(struct sk_buff *skb)
 268 {
 269         mutex_lock(&sock_diag_mutex);
 270         netlink_rcv_skb(skb, &sock_diag_rcv_msg);
 271         mutex_unlock(&sock_diag_mutex);
 272 }
 273
 274 static int sock_diag_bind(struct net *net, int group)
 275 {
 276         switch (group) {
 277         case SKNLGRP_INET_TCP_DESTROY:
 278         case SKNLGRP_INET_UDP_DESTROY:
 279                 if (!sock_diag_handlers[AF_INET])
 280                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 281                                        NETLINK_SOCK_DIAG, AF_INET);
 282                 break;
 283         case SKNLGRP_INET6_TCP_DESTROY:
 284         case SKNLGRP_INET6_UDP_DESTROY:
 285                 if (!sock_diag_handlers[AF_INET6])
 286                         request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,
 287                                        NETLINK_SOCK_DIAG, AF_INET);
 288                 break;
 289         }
 290         return 0;
 291 }
 292
 293 static int __net_init diag_net_init(struct net *net)
 294 {
 295         struct netlink_kernel_cfg cfg = {
 296                 .groups = SKNLGRP_MAX,
 297                 .input  = sock_diag_rcv,
 298                 .bind   = sock_diag_bind,
 299                 .flags  = NL_CFG_F_NONROOT_RECV,
 300         };
 301
 302         net->diag_nlsk = netlink_kernel_create(net, NETLINK_SOCK_DIAG, &cfg);
 303         return net->diag_nlsk == NULL ? -ENOMEM : 0;
 304 }
 305
 306 static void __net_exit diag_net_exit(struct net *net)
 307 {
 308         netlink_kernel_release(net->diag_nlsk);
 309         net->diag_nlsk = NULL;
 310 }
 311
 312 static struct pernet_operations diag_net_ops = {
 313         .init = diag_net_init,
 314         .exit = diag_net_exit,
 315 };
 316
 317 static int __init sock_diag_init(void)
 318 {
 319         broadcast_wq = alloc_workqueue("sock_diag_events", 0, 0);
 320         BUG_ON(!broadcast_wq);
 321         return register_pernet_subsys(&diag_net_ops);
 322 }
 323
 324 static void __exit sock_diag_exit(void)
 325 {
 326         unregister_pernet_subsys(&diag_net_ops);
 327         destroy_workqueue(broadcast_wq);
 328 }
 329
 330 module_init(sock_diag_init);
 331 module_exit(sock_diag_exit);
 332 MODULE_LICENSE("GPL");
 333 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_SOCK_DIAG);