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 <net/sock.h> 17#include <net/af_rxrpc.h> 18#include "ar-internal.h" 19 20static LIST_HEAD(rxrpc_locals); 21DEFINE_RWLOCK(rxrpc_local_lock); 22static DECLARE_RWSEM(rxrpc_local_sem); 23static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq); 24 25static void rxrpc_destroy_local(struct work_struct *work); 26 27/* 28 * allocate a new local 29 */ 30static 31struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx) 32{ 33 struct rxrpc_local *local; 34 35 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); 36 if (local) { 37 INIT_WORK(&local->destroyer, &rxrpc_destroy_local); 38 INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls); 39 INIT_WORK(&local->rejecter, &rxrpc_reject_packets); 40 INIT_LIST_HEAD(&local->services); 41 INIT_LIST_HEAD(&local->link); 42 init_rwsem(&local->defrag_sem); 43 skb_queue_head_init(&local->accept_queue); 44 skb_queue_head_init(&local->reject_queue); 45 spin_lock_init(&local->lock); 46 rwlock_init(&local->services_lock); 47 atomic_set(&local->usage, 1); 48 local->debug_id = atomic_inc_return(&rxrpc_debug_id); 49 memcpy(&local->srx, srx, sizeof(*srx)); 50 } 51 52 _leave(" = %p", local); 53 return local; 54} 55 56/* 57 * create the local socket 58 * - must be called with rxrpc_local_sem writelocked 59 */ 60static int rxrpc_create_local(struct rxrpc_local *local) 61{ 62 struct sock *sock; 63 int ret, opt; 64 65 _enter("%p{%d}", local, local->srx.transport_type); 66 67 /* create a socket to represent the local endpoint */ 68 ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP, 69 &local->socket); 70 if (ret < 0) { 71 _leave(" = %d [socket]", ret); 72 return ret; 73 } 74 75 /* if a local address was supplied then bind it */ 76 if (local->srx.transport_len > sizeof(sa_family_t)) { 77 _debug("bind"); 78 ret = kernel_bind(local->socket, 79 (struct sockaddr *) &local->srx.transport, 80 local->srx.transport_len); 81 if (ret < 0) { 82 _debug("bind failed"); 83 goto error; 84 } 85 } 86 87 /* we want to receive ICMP errors */ 88 opt = 1; 89 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR, 90 (char *) &opt, sizeof(opt)); 91 if (ret < 0) { 92 _debug("setsockopt failed"); 93 goto error; 94 } 95 96 /* we want to set the don't fragment bit */ 97 opt = IP_PMTUDISC_DO; 98 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER, 99 (char *) &opt, sizeof(opt)); 100 if (ret < 0) { 101 _debug("setsockopt failed"); 102 goto error; 103 } 104 105 write_lock_bh(&rxrpc_local_lock); 106 list_add(&local->link, &rxrpc_locals); 107 write_unlock_bh(&rxrpc_local_lock); 108 109 /* set the socket up */ 110 sock = local->socket->sk; 111 sock->sk_user_data = local; 112 sock->sk_data_ready = rxrpc_data_ready; 113 sock->sk_error_report = rxrpc_UDP_error_report; 114 _leave(" = 0"); 115 return 0; 116 117error: 118 kernel_sock_shutdown(local->socket, SHUT_RDWR); 119 local->socket->sk->sk_user_data = NULL; 120 sock_release(local->socket); 121 local->socket = NULL; 122 123 _leave(" = %d", ret); 124 return ret; 125} 126 127/* 128 * create a new local endpoint using the specified UDP address 129 */ 130struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx) 131{ 132 struct rxrpc_local *local; 133 int ret; 134 135 _enter("{%d,%u,%pI4+%hu}", 136 srx->transport_type, 137 srx->transport.family, 138 &srx->transport.sin.sin_addr, 139 ntohs(srx->transport.sin.sin_port)); 140 141 down_write(&rxrpc_local_sem); 142 143 /* see if we have a suitable local local endpoint already */ 144 read_lock_bh(&rxrpc_local_lock); 145 146 list_for_each_entry(local, &rxrpc_locals, link) { 147 _debug("CMP {%d,%u,%pI4+%hu}", 148 local->srx.transport_type, 149 local->srx.transport.family, 150 &local->srx.transport.sin.sin_addr, 151 ntohs(local->srx.transport.sin.sin_port)); 152 153 if (local->srx.transport_type != srx->transport_type || 154 local->srx.transport.family != srx->transport.family) 155 continue; 156 157 switch (srx->transport.family) { 158 case AF_INET: 159 if (local->srx.transport.sin.sin_port != 160 srx->transport.sin.sin_port) 161 continue; 162 if (memcmp(&local->srx.transport.sin.sin_addr, 163 &srx->transport.sin.sin_addr, 164 sizeof(struct in_addr)) != 0) 165 continue; 166 goto found_local; 167 168 default: 169 BUG(); 170 } 171 } 172 173 read_unlock_bh(&rxrpc_local_lock); 174 175 /* we didn't find one, so we need to create one */ 176 local = rxrpc_alloc_local(srx); 177 if (!local) { 178 up_write(&rxrpc_local_sem); 179 return ERR_PTR(-ENOMEM); 180 } 181 182 ret = rxrpc_create_local(local); 183 if (ret < 0) { 184 up_write(&rxrpc_local_sem); 185 kfree(local); 186 _leave(" = %d", ret); 187 return ERR_PTR(ret); 188 } 189 190 up_write(&rxrpc_local_sem); 191 192 _net("LOCAL new %d {%d,%u,%pI4+%hu}", 193 local->debug_id, 194 local->srx.transport_type, 195 local->srx.transport.family, 196 &local->srx.transport.sin.sin_addr, 197 ntohs(local->srx.transport.sin.sin_port)); 198 199 _leave(" = %p [new]", local); 200 return local; 201 202found_local: 203 rxrpc_get_local(local); 204 read_unlock_bh(&rxrpc_local_lock); 205 up_write(&rxrpc_local_sem); 206 207 _net("LOCAL old %d {%d,%u,%pI4+%hu}", 208 local->debug_id, 209 local->srx.transport_type, 210 local->srx.transport.family, 211 &local->srx.transport.sin.sin_addr, 212 ntohs(local->srx.transport.sin.sin_port)); 213 214 _leave(" = %p [reuse]", local); 215 return local; 216} 217 218/* 219 * release a local endpoint 220 */ 221void rxrpc_put_local(struct rxrpc_local *local) 222{ 223 _enter("%p{u=%d}", local, atomic_read(&local->usage)); 224 225 ASSERTCMP(atomic_read(&local->usage), >, 0); 226 227 /* to prevent a race, the decrement and the dequeue must be effectively 228 * atomic */ 229 write_lock_bh(&rxrpc_local_lock); 230 if (unlikely(atomic_dec_and_test(&local->usage))) { 231 _debug("destroy local"); 232 rxrpc_queue_work(&local->destroyer); 233 } 234 write_unlock_bh(&rxrpc_local_lock); 235 _leave(""); 236} 237 238/* 239 * destroy a local endpoint 240 */ 241static void rxrpc_destroy_local(struct work_struct *work) 242{ 243 struct rxrpc_local *local = 244 container_of(work, struct rxrpc_local, destroyer); 245 246 _enter("%p{%d}", local, atomic_read(&local->usage)); 247 248 down_write(&rxrpc_local_sem); 249 250 write_lock_bh(&rxrpc_local_lock); 251 if (atomic_read(&local->usage) > 0) { 252 write_unlock_bh(&rxrpc_local_lock); 253 up_read(&rxrpc_local_sem); 254 _leave(" [resurrected]"); 255 return; 256 } 257 258 list_del(&local->link); 259 local->socket->sk->sk_user_data = NULL; 260 write_unlock_bh(&rxrpc_local_lock); 261 262 downgrade_write(&rxrpc_local_sem); 263 264 ASSERT(list_empty(&local->services)); 265 ASSERT(!work_pending(&local->acceptor)); 266 ASSERT(!work_pending(&local->rejecter)); 267 268 /* finish cleaning up the local descriptor */ 269 rxrpc_purge_queue(&local->accept_queue); 270 rxrpc_purge_queue(&local->reject_queue); 271 kernel_sock_shutdown(local->socket, SHUT_RDWR); 272 sock_release(local->socket); 273 274 up_read(&rxrpc_local_sem); 275 276 _net("DESTROY LOCAL %d", local->debug_id); 277 kfree(local); 278 279 if (list_empty(&rxrpc_locals)) 280 wake_up_all(&rxrpc_local_wq); 281 282 _leave(""); 283} 284 285/* 286 * preemptively destroy all local local endpoint rather than waiting for 287 * them to be destroyed 288 */ 289void __exit rxrpc_destroy_all_locals(void) 290{ 291 DECLARE_WAITQUEUE(myself,current); 292 293 _enter(""); 294 295 /* we simply have to wait for them to go away */ 296 if (!list_empty(&rxrpc_locals)) { 297 set_current_state(TASK_UNINTERRUPTIBLE); 298 add_wait_queue(&rxrpc_local_wq, &myself); 299 300 while (!list_empty(&rxrpc_locals)) { 301 schedule(); 302 set_current_state(TASK_UNINTERRUPTIBLE); 303 } 304 305 remove_wait_queue(&rxrpc_local_wq, &myself); 306 set_current_state(TASK_RUNNING); 307 } 308 309 _leave(""); 310} 311