net/core/sock_diag.c

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