David Howells | 17926a7 | 2007-04-26 15:48:28 -0700 | [diff] [blame] | 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 <net/sock.h> |
| 16 | #include <net/af_rxrpc.h> |
| 17 | #include "ar-internal.h" |
| 18 | |
| 19 | static LIST_HEAD(rxrpc_locals); |
| 20 | DEFINE_RWLOCK(rxrpc_local_lock); |
| 21 | static DECLARE_RWSEM(rxrpc_local_sem); |
| 22 | static DECLARE_WAIT_QUEUE_HEAD(rxrpc_local_wq); |
| 23 | |
| 24 | static void rxrpc_destroy_local(struct work_struct *work); |
| 25 | |
| 26 | /* |
| 27 | * allocate a new local |
| 28 | */ |
| 29 | static |
| 30 | struct rxrpc_local *rxrpc_alloc_local(struct sockaddr_rxrpc *srx) |
| 31 | { |
| 32 | struct rxrpc_local *local; |
| 33 | |
| 34 | local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); |
| 35 | if (local) { |
| 36 | INIT_WORK(&local->destroyer, &rxrpc_destroy_local); |
| 37 | INIT_WORK(&local->acceptor, &rxrpc_accept_incoming_calls); |
| 38 | INIT_WORK(&local->rejecter, &rxrpc_reject_packets); |
| 39 | INIT_LIST_HEAD(&local->services); |
| 40 | INIT_LIST_HEAD(&local->link); |
| 41 | init_rwsem(&local->defrag_sem); |
| 42 | skb_queue_head_init(&local->accept_queue); |
| 43 | skb_queue_head_init(&local->reject_queue); |
| 44 | spin_lock_init(&local->lock); |
| 45 | rwlock_init(&local->services_lock); |
| 46 | atomic_set(&local->usage, 1); |
| 47 | local->debug_id = atomic_inc_return(&rxrpc_debug_id); |
| 48 | memcpy(&local->srx, srx, sizeof(*srx)); |
| 49 | } |
| 50 | |
| 51 | _leave(" = %p", local); |
| 52 | return local; |
| 53 | } |
| 54 | |
| 55 | /* |
| 56 | * create the local socket |
| 57 | * - must be called with rxrpc_local_sem writelocked |
| 58 | */ |
| 59 | static int rxrpc_create_local(struct rxrpc_local *local) |
| 60 | { |
| 61 | struct sock *sock; |
| 62 | int ret, opt; |
| 63 | |
| 64 | _enter("%p{%d}", local, local->srx.transport_type); |
| 65 | |
| 66 | /* create a socket to represent the local endpoint */ |
| 67 | ret = sock_create_kern(PF_INET, local->srx.transport_type, IPPROTO_UDP, |
| 68 | &local->socket); |
| 69 | if (ret < 0) { |
| 70 | _leave(" = %d [socket]", ret); |
| 71 | return ret; |
| 72 | } |
| 73 | |
| 74 | /* if a local address was supplied then bind it */ |
| 75 | if (local->srx.transport_len > sizeof(sa_family_t)) { |
| 76 | _debug("bind"); |
| 77 | ret = kernel_bind(local->socket, |
| 78 | (struct sockaddr *) &local->srx.transport, |
| 79 | local->srx.transport_len); |
| 80 | if (ret < 0) { |
| 81 | _debug("bind failed"); |
| 82 | goto error; |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | /* we want to receive ICMP errors */ |
| 87 | opt = 1; |
| 88 | ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR, |
| 89 | (char *) &opt, sizeof(opt)); |
| 90 | if (ret < 0) { |
| 91 | _debug("setsockopt failed"); |
| 92 | goto error; |
| 93 | } |
| 94 | |
| 95 | /* we want to set the don't fragment bit */ |
| 96 | opt = IP_PMTUDISC_DO; |
| 97 | ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER, |
| 98 | (char *) &opt, sizeof(opt)); |
| 99 | if (ret < 0) { |
| 100 | _debug("setsockopt failed"); |
| 101 | goto error; |
| 102 | } |
| 103 | |
| 104 | write_lock_bh(&rxrpc_local_lock); |
| 105 | list_add(&local->link, &rxrpc_locals); |
| 106 | write_unlock_bh(&rxrpc_local_lock); |
| 107 | |
| 108 | /* set the socket up */ |
| 109 | sock = local->socket->sk; |
| 110 | sock->sk_user_data = local; |
| 111 | sock->sk_data_ready = rxrpc_data_ready; |
| 112 | sock->sk_error_report = rxrpc_UDP_error_report; |
| 113 | _leave(" = 0"); |
| 114 | return 0; |
| 115 | |
| 116 | error: |
| 117 | local->socket->ops->shutdown(local->socket, 2); |
| 118 | local->socket->sk->sk_user_data = NULL; |
| 119 | sock_release(local->socket); |
| 120 | local->socket = NULL; |
| 121 | |
| 122 | _leave(" = %d", ret); |
| 123 | return ret; |
| 124 | } |
| 125 | |
| 126 | /* |
| 127 | * create a new local endpoint using the specified UDP address |
| 128 | */ |
| 129 | struct rxrpc_local *rxrpc_lookup_local(struct sockaddr_rxrpc *srx) |
| 130 | { |
| 131 | struct rxrpc_local *local; |
| 132 | int ret; |
| 133 | |
| 134 | _enter("{%d,%u,%u.%u.%u.%u+%hu}", |
| 135 | srx->transport_type, |
| 136 | srx->transport.family, |
| 137 | NIPQUAD(srx->transport.sin.sin_addr), |
| 138 | ntohs(srx->transport.sin.sin_port)); |
| 139 | |
| 140 | down_write(&rxrpc_local_sem); |
| 141 | |
| 142 | /* see if we have a suitable local local endpoint already */ |
| 143 | read_lock_bh(&rxrpc_local_lock); |
| 144 | |
| 145 | list_for_each_entry(local, &rxrpc_locals, link) { |
| 146 | _debug("CMP {%d,%u,%u.%u.%u.%u+%hu}", |
| 147 | local->srx.transport_type, |
| 148 | local->srx.transport.family, |
| 149 | NIPQUAD(local->srx.transport.sin.sin_addr), |
| 150 | ntohs(local->srx.transport.sin.sin_port)); |
| 151 | |
| 152 | if (local->srx.transport_type != srx->transport_type || |
| 153 | local->srx.transport.family != srx->transport.family) |
| 154 | continue; |
| 155 | |
| 156 | switch (srx->transport.family) { |
| 157 | case AF_INET: |
| 158 | if (local->srx.transport.sin.sin_port != |
| 159 | srx->transport.sin.sin_port) |
| 160 | continue; |
| 161 | if (memcmp(&local->srx.transport.sin.sin_addr, |
| 162 | &srx->transport.sin.sin_addr, |
| 163 | sizeof(struct in_addr)) != 0) |
| 164 | continue; |
| 165 | goto found_local; |
| 166 | |
| 167 | default: |
| 168 | BUG(); |
| 169 | } |
| 170 | } |
| 171 | |
| 172 | read_unlock_bh(&rxrpc_local_lock); |
| 173 | |
| 174 | /* we didn't find one, so we need to create one */ |
| 175 | local = rxrpc_alloc_local(srx); |
| 176 | if (!local) { |
| 177 | up_write(&rxrpc_local_sem); |
| 178 | return ERR_PTR(-ENOMEM); |
| 179 | } |
| 180 | |
| 181 | ret = rxrpc_create_local(local); |
| 182 | if (ret < 0) { |
| 183 | up_write(&rxrpc_local_sem); |
| 184 | kfree(local); |
| 185 | _leave(" = %d", ret); |
| 186 | return ERR_PTR(ret); |
| 187 | } |
| 188 | |
| 189 | up_write(&rxrpc_local_sem); |
| 190 | |
| 191 | _net("LOCAL new %d {%d,%u,%u.%u.%u.%u+%hu}", |
| 192 | local->debug_id, |
| 193 | local->srx.transport_type, |
| 194 | local->srx.transport.family, |
| 195 | NIPQUAD(local->srx.transport.sin.sin_addr), |
| 196 | ntohs(local->srx.transport.sin.sin_port)); |
| 197 | |
| 198 | _leave(" = %p [new]", local); |
| 199 | return local; |
| 200 | |
| 201 | found_local: |
| 202 | rxrpc_get_local(local); |
| 203 | read_unlock_bh(&rxrpc_local_lock); |
| 204 | up_write(&rxrpc_local_sem); |
| 205 | |
| 206 | _net("LOCAL old %d {%d,%u,%u.%u.%u.%u+%hu}", |
| 207 | local->debug_id, |
| 208 | local->srx.transport_type, |
| 209 | local->srx.transport.family, |
| 210 | NIPQUAD(local->srx.transport.sin.sin_addr), |
| 211 | ntohs(local->srx.transport.sin.sin_port)); |
| 212 | |
| 213 | _leave(" = %p [reuse]", local); |
| 214 | return local; |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * release a local endpoint |
| 219 | */ |
| 220 | void rxrpc_put_local(struct rxrpc_local *local) |
| 221 | { |
| 222 | _enter("%p{u=%d}", local, atomic_read(&local->usage)); |
| 223 | |
| 224 | ASSERTCMP(atomic_read(&local->usage), >, 0); |
| 225 | |
| 226 | /* to prevent a race, the decrement and the dequeue must be effectively |
| 227 | * atomic */ |
| 228 | write_lock_bh(&rxrpc_local_lock); |
| 229 | if (unlikely(atomic_dec_and_test(&local->usage))) { |
| 230 | _debug("destroy local"); |
| 231 | schedule_work(&local->destroyer); |
| 232 | } |
| 233 | write_unlock_bh(&rxrpc_local_lock); |
| 234 | _leave(""); |
| 235 | } |
| 236 | |
| 237 | /* |
| 238 | * destroy a local endpoint |
| 239 | */ |
| 240 | static void rxrpc_destroy_local(struct work_struct *work) |
| 241 | { |
| 242 | struct rxrpc_local *local = |
| 243 | container_of(work, struct rxrpc_local, destroyer); |
| 244 | |
| 245 | _enter("%p{%d}", local, atomic_read(&local->usage)); |
| 246 | |
| 247 | down_write(&rxrpc_local_sem); |
| 248 | |
| 249 | write_lock_bh(&rxrpc_local_lock); |
| 250 | if (atomic_read(&local->usage) > 0) { |
| 251 | write_unlock_bh(&rxrpc_local_lock); |
| 252 | up_read(&rxrpc_local_sem); |
| 253 | _leave(" [resurrected]"); |
| 254 | return; |
| 255 | } |
| 256 | |
| 257 | list_del(&local->link); |
| 258 | local->socket->sk->sk_user_data = NULL; |
| 259 | write_unlock_bh(&rxrpc_local_lock); |
| 260 | |
| 261 | downgrade_write(&rxrpc_local_sem); |
| 262 | |
| 263 | ASSERT(list_empty(&local->services)); |
| 264 | ASSERT(!work_pending(&local->acceptor)); |
| 265 | ASSERT(!work_pending(&local->rejecter)); |
| 266 | |
| 267 | /* finish cleaning up the local descriptor */ |
| 268 | rxrpc_purge_queue(&local->accept_queue); |
| 269 | rxrpc_purge_queue(&local->reject_queue); |
| 270 | local->socket->ops->shutdown(local->socket, 2); |
| 271 | sock_release(local->socket); |
| 272 | |
| 273 | up_read(&rxrpc_local_sem); |
| 274 | |
| 275 | _net("DESTROY LOCAL %d", local->debug_id); |
| 276 | kfree(local); |
| 277 | |
| 278 | if (list_empty(&rxrpc_locals)) |
| 279 | wake_up_all(&rxrpc_local_wq); |
| 280 | |
| 281 | _leave(""); |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * preemptively destroy all local local endpoint rather than waiting for |
| 286 | * them to be destroyed |
| 287 | */ |
| 288 | void __exit rxrpc_destroy_all_locals(void) |
| 289 | { |
| 290 | DECLARE_WAITQUEUE(myself,current); |
| 291 | |
| 292 | _enter(""); |
| 293 | |
| 294 | /* we simply have to wait for them to go away */ |
| 295 | if (!list_empty(&rxrpc_locals)) { |
| 296 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 297 | add_wait_queue(&rxrpc_local_wq, &myself); |
| 298 | |
| 299 | while (!list_empty(&rxrpc_locals)) { |
| 300 | schedule(); |
| 301 | set_current_state(TASK_UNINTERRUPTIBLE); |
| 302 | } |
| 303 | |
| 304 | remove_wait_queue(&rxrpc_local_wq, &myself); |
| 305 | set_current_state(TASK_RUNNING); |
| 306 | } |
| 307 | |
| 308 | _leave(""); |
| 309 | } |