kernel/net/rxrpc/ar-local.c

   1 /* AF_RXRPC local endpoint management
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/slab.h>
  16 #include <linux/udp.h>
  17 #include <linux/ip.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include <generated/utsrelease.h>
  21 #include "ar-internal.h"
  22
  23 static const char rxrpc_version_string[65] = "linux-" UTS_RELEASE " AF_RXRPC";
  24
  25 static LIST_HEAD(rxrpc_locals);
  26 DEFINE_RWLOCK(rxrpc_local_lock);
  27 static DECLARE_RWSEM(rxrpc_local_sem);
  28 static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq);
  29
  30 static void rxrpc_destroy_local(struct work_struct *work);
  31 static void rxrpc_process_local_events(struct work_struct *work);
  32
  33 /*
  34  * allocate a new local
  35  */
  36 static
  37 struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx)
  38 {
  39         struct rxrpc_local *local;
  40
  41         local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL);
  42         if (local) {
  43                 INIT_WORK(&local->destroyer, &rxrpc_destroy_local);
  44                 INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls);
  45                 INIT_WORK(&local->rejecter, &rxrpc_reject_packets);
  46                 INIT_WORK(&local->event_processor, &rxrpc_process_local_events);
  47                 INIT_LIST_HEAD(&local->services);
  48                 INIT_LIST_HEAD(&local->link);
  49                 init_rwsem(&local->defrag_sem);
  50                 skb_queue_head_init(&local->accept_queue);
  51                 skb_queue_head_init(&local->reject_queue);
  52                 skb_queue_head_init(&local->event_queue);
  53                 spin_lock_init(&local->lock);
  54                 rwlock_init(&local->services_lock);
  55                 atomic_set(&local->usage, 1);
  56                 local->debug_id = atomic_inc_return(&rxrpc_debug_id);
  57                 memcpy(&local->srx, srx, sizeof(*srx));
  58         }
  59
  60         _leave(" = %p", local);
  61         return local;
  62 }
  63
  64 /*
  65  * create the local socket
  66  * - must be called with rxrpc_local_sem writelocked
  67  */
  68 static int rxrpc_create_local(struct rxrpc_local *local)
  69 {
  70         struct sock *sock;
  71         int ret, opt;
  72
  73         _enter("%p{%d}", local, local->srx.transport_type);
  74
  75         /* create a socket to represent the local endpoint */
  76         ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP,
  77                                &local->socket);
  78         if (ret < 0) {
  79                 _leave(" = %d [socket]", ret);
  80                 return ret;
  81         }
  82
  83         /* if a local address was supplied then bind it */
  84         if (local->srx.transport_len > sizeof(sa_family_t)) {
  85                 _debug("bind");
  86                 ret = kernel_bind(local->socket,
  87                                   (struct sockaddr *) &local->srx.transport,
  88                                   local->srx.transport_len);
  89                 if (ret < 0) {
  90                         _debug("bind failed");
  91                         goto error;
  92                 }
  93         }
  94
  95         /* we want to receive ICMP errors */
  96         opt = 1;
  97         ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR,
  98                                 (char *) &opt, sizeof(opt));
  99         if (ret < 0) {
 100                 _debug("setsockopt failed");
 101                 goto error;
 102         }
 103
 104         /* we want to set the don't fragment bit */
 105         opt = IP_PMTUDISC_DO;
 106         ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER,
 107                                 (char *) &opt, sizeof(opt));
 108         if (ret < 0) {
 109                 _debug("setsockopt failed");
 110                 goto error;
 111         }
 112
 113         write_lock_bh(&rxrpc_local_lock);
 114         list_add(&local->link, &rxrpc_locals);
 115         write_unlock_bh(&rxrpc_local_lock);
 116
 117         /* set the socket up */
 118         sock = local->socket->sk;
 119         sock->sk_user_data      = local;
 120         sock->sk_data_ready     = rxrpc_data_ready;
 121         sock->sk_error_report   = rxrpc_UDP_error_report;
 122         _leave(" = 0");
 123         return 0;
 124
 125 error:
 126         kernel_sock_shutdown(local->socket, SHUT_RDWR);
 127         local->socket->sk->sk_user_data = NULL;
 128         sock_release(local->socket);
 129         local->socket = NULL;
 130
 131         _leave(" = %d", ret);
 132         return ret;
 133 }
 134
 135 /*
 136  * create a new local endpoint using the specified UDP address
 137  */
 138 struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx)
 139 {
 140         struct rxrpc_local *local;
 141         int ret;
 142
 143         _enter("{%d,%u,%pI4+%hu}",
 144                srx->transport_type,
 145                srx->transport.family,
 146                &srx->transport.sin.sin_addr,
 147                ntohs(srx->transport.sin.sin_port));
 148
 149         down_write(&rxrpc_local_sem);
 150
 151         /* see if we have a suitable local local endpoint already */
 152         read_lock_bh(&rxrpc_local_lock);
 153
 154         list_for_each_entry(local, &rxrpc_locals, link) {
 155                 _debug("CMP {%d,%u,%pI4+%hu}",
 156                        local->srx.transport_type,
 157                        local->srx.transport.family,
 158                        &local->srx.transport.sin.sin_addr,
 159                        ntohs(local->srx.transport.sin.sin_port));
 160
 161                 if (local->srx.transport_type != srx->transport_type ||
 162                     local->srx.transport.family != srx->transport.family)
 163                         continue;
 164
 165                 switch (srx->transport.family) {
 166                 case AF_INET:
 167                         if (local->srx.transport.sin.sin_port !=
 168                             srx->transport.sin.sin_port)
 169                                 continue;
 170                         if (memcmp(&local->srx.transport.sin.sin_addr,
 171                                    &srx->transport.sin.sin_addr,
 172                                    sizeof(struct in_addr)) != 0)
 173                                 continue;
 174                         goto found_local;
 175
 176                 default:
 177                         BUG();
 178                 }
 179         }
 180
 181         read_unlock_bh(&rxrpc_local_lock);
 182
 183         /* we didn't find one, so we need to create one */
 184         local = rxrpc_alloc_local(srx);
 185         if (!local) {
 186                 up_write(&rxrpc_local_sem);
 187                 return ERR_PTR(-ENOMEM);
 188         }
 189
 190         ret = rxrpc_create_local(local);
 191         if (ret < 0) {
 192                 up_write(&rxrpc_local_sem);
 193                 kfree(local);
 194                 _leave(" = %d", ret);
 195                 return ERR_PTR(ret);
 196         }
 197
 198         up_write(&rxrpc_local_sem);
 199
 200         _net("LOCAL new %d {%d,%u,%pI4+%hu}",
 201              local->debug_id,
 202              local->srx.transport_type,
 203              local->srx.transport.family,
 204              &local->srx.transport.sin.sin_addr,
 205              ntohs(local->srx.transport.sin.sin_port));
 206
 207         _leave(" = %p [new]", local);
 208         return local;
 209
 210 found_local:
 211         rxrpc_get_local(local);
 212         read_unlock_bh(&rxrpc_local_lock);
 213         up_write(&rxrpc_local_sem);
 214
 215         _net("LOCAL old %d {%d,%u,%pI4+%hu}",
 216              local->debug_id,
 217              local->srx.transport_type,
 218              local->srx.transport.family,
 219              &local->srx.transport.sin.sin_addr,
 220              ntohs(local->srx.transport.sin.sin_port));
 221
 222         _leave(" = %p [reuse]", local);
 223         return local;
 224 }
 225
 226 /*
 227  * release a local endpoint
 228  */
 229 void rxrpc_put_local(struct rxrpc_local *local)
 230 {
 231         _enter("%p{u=%d}", local, atomic_read(&local->usage));
 232
 233         ASSERTCMP(atomic_read(&local->usage), >, 0);
 234
 235         /* to prevent a race, the decrement and the dequeue must be effectively
 236          * atomic */
 237         write_lock_bh(&rxrpc_local_lock);
 238         if (unlikely(atomic_dec_and_test(&local->usage))) {
 239                 _debug("destroy local");
 240                 rxrpc_queue_work(&local->destroyer);
 241         }
 242         write_unlock_bh(&rxrpc_local_lock);
 243         _leave("");
 244 }
 245
 246 /*
 247  * destroy a local endpoint
 248  */
 249 static void rxrpc_destroy_local(struct work_struct *work)
 250 {
 251         struct rxrpc_local *local =
 252                 container_of(work, struct rxrpc_local, destroyer);
 253
 254         _enter("%p{%d}", local, atomic_read(&local->usage));
 255
 256         down_write(&rxrpc_local_sem);
 257
 258         write_lock_bh(&rxrpc_local_lock);
 259         if (atomic_read(&local->usage) > 0) {
 260                 write_unlock_bh(&rxrpc_local_lock);
 261                 up_read(&rxrpc_local_sem);
 262                 _leave(" [resurrected]");
 263                 return;
 264         }
 265
 266         list_del(&local->link);
 267         local->socket->sk->sk_user_data = NULL;
 268         write_unlock_bh(&rxrpc_local_lock);
 269
 270         downgrade_write(&rxrpc_local_sem);
 271
 272         ASSERT(list_empty(&local->services));
 273         ASSERT(!work_pending(&local->acceptor));
 274         ASSERT(!work_pending(&local->rejecter));
 275         ASSERT(!work_pending(&local->event_processor));
 276
 277         /* finish cleaning up the local descriptor */
 278         rxrpc_purge_queue(&local->accept_queue);
 279         rxrpc_purge_queue(&local->reject_queue);
 280         rxrpc_purge_queue(&local->event_queue);
 281         kernel_sock_shutdown(local->socket, SHUT_RDWR);
 282         sock_release(local->socket);
 283
 284         up_read(&rxrpc_local_sem);
 285
 286         _net("DESTROY LOCAL %d", local->debug_id);
 287         kfree(local);
 288
 289         if (list_empty(&rxrpc_locals))
 290                 wake_up_all(&rxrpc_local_wq);
 291
 292         _leave("");
 293 }
 294
 295 /*
 296  * preemptively destroy all local local endpoint rather than waiting for
 297  * them to be destroyed
 298  */
 299 void __exit rxrpc_destroy_all_locals(void)
 300 {
 301         DECLARE_WAITQUEUE(myself,current);
 302
 303         _enter("");
 304
 305         /* we simply have to wait for them to go away */
 306         if (!list_empty(&rxrpc_locals)) {
 307                 set_current_state(TASK_UNINTERRUPTIBLE);
 308                 add_wait_queue(&rxrpc_local_wq, &myself);
 309
 310                 while (!list_empty(&rxrpc_locals)) {
 311                         schedule();
 312                         set_current_state(TASK_UNINTERRUPTIBLE);
 313                 }
 314
 315                 remove_wait_queue(&rxrpc_local_wq, &myself);
 316                 set_current_state(TASK_RUNNING);
 317         }
 318
 319         _leave("");
 320 }
 321
 322 /*
 323  * Reply to a version request
 324  */
 325 static void rxrpc_send_version_request(struct rxrpc_local *local,
 326                                        struct rxrpc_header *hdr,
 327                                        struct sk_buff *skb)
 328 {
 329         struct sockaddr_in sin;
 330         struct msghdr msg;
 331         struct kvec iov[2];
 332         size_t len;
 333         int ret;
 334
 335         _enter("");
 336
 337         sin.sin_family = AF_INET;
 338         sin.sin_port = udp_hdr(skb)->source;
 339         sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 340
 341         msg.msg_name    = &sin;
 342         msg.msg_namelen = sizeof(sin);
 343         msg.msg_control = NULL;
 344         msg.msg_controllen = 0;
 345         msg.msg_flags   = 0;
 346
 347         hdr->seq        = 0;
 348         hdr->serial     = 0;
 349         hdr->type       = RXRPC_PACKET_TYPE_VERSION;
 350         hdr->flags      = RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
 351         hdr->userStatus = 0;
 352         hdr->_rsvd      = 0;
 353
 354         iov[0].iov_base = hdr;
 355         iov[0].iov_len  = sizeof(*hdr);
 356         iov[1].iov_base = (char *)rxrpc_version_string;
 357         iov[1].iov_len  = sizeof(rxrpc_version_string);
 358
 359         len = iov[0].iov_len + iov[1].iov_len;
 360
 361         _proto("Tx VERSION (reply)");
 362
 363         ret = kernel_sendmsg(local->socket, &msg, iov, 2, len);
 364         if (ret < 0)
 365                 _debug("sendmsg failed: %d", ret);
 366
 367         _leave("");
 368 }
 369
 370 /*
 371  * Process event packets targetted at a local endpoint.
 372  */
 373 static void rxrpc_process_local_events(struct work_struct *work)
 374 {
 375         struct rxrpc_local *local = container_of(work, struct rxrpc_local, event_processor);
 376         struct sk_buff *skb;
 377         char v;
 378
 379         _enter("");
 380
 381         atomic_inc(&local->usage);
 382
 383         while ((skb = skb_dequeue(&local->event_queue))) {
 384                 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 385
 386                 kdebug("{%d},{%u}", local->debug_id, sp->hdr.type);
 387
 388                 switch (sp->hdr.type) {
 389                 case RXRPC_PACKET_TYPE_VERSION:
 390                         if (skb_copy_bits(skb, 0, &v, 1) < 0)
 391                                 return;
 392                         _proto("Rx VERSION { %02x }", v);
 393                         if (v == 0)
 394                                 rxrpc_send_version_request(local, &sp->hdr, skb);
 395                         break;
 396
 397                 default:
 398                         /* Just ignore anything we don't understand */
 399                         break;
 400                 }
 401
 402                 rxrpc_put_local(local);
 403                 rxrpc_free_skb(skb);
 404         }
 405
 406         rxrpc_put_local(local);
 407         _leave("");
 408 }