1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* incoming call handling 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/net.h> 12 #include <linux/skbuff.h> 13 #include <linux/errqueue.h> 14 #include <linux/udp.h> 15 #include <linux/in.h> 16 #include <linux/in6.h> 17 #include <linux/icmp.h> 18 #include <linux/gfp.h> 19 #include <linux/circ_buf.h> 20 #include <net/sock.h> 21 #include <net/af_rxrpc.h> 22 #include <net/ip.h> 23 #include "ar-internal.h" 24 25 static void rxrpc_dummy_notify(struct sock *sk, struct rxrpc_call *call, 26 unsigned long user_call_ID) 27 { 28 } 29 30 /* 31 * Preallocate a single service call, connection and peer and, if possible, 32 * give them a user ID and attach the user's side of the ID to them. 33 */ 34 static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx, 35 struct rxrpc_backlog *b, 36 rxrpc_notify_rx_t notify_rx, 37 rxrpc_user_attach_call_t user_attach_call, 38 unsigned long user_call_ID, gfp_t gfp, 39 unsigned int debug_id) 40 { 41 struct rxrpc_call *call, *xcall; 42 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); 43 struct rb_node *parent, **pp; 44 int max, tmp; 45 unsigned int size = RXRPC_BACKLOG_MAX; 46 unsigned int head, tail, call_head, call_tail; 47 48 max = rx->sk.sk_max_ack_backlog; 49 tmp = rx->sk.sk_ack_backlog; 50 if (tmp >= max) { 51 _leave(" = -ENOBUFS [full %u]", max); 52 return -ENOBUFS; 53 } 54 max -= tmp; 55 56 /* We don't need more conns and peers than we have calls, but on the 57 * other hand, we shouldn't ever use more peers than conns or conns 58 * than calls. 59 */ 60 call_head = b->call_backlog_head; 61 call_tail = READ_ONCE(b->call_backlog_tail); 62 tmp = CIRC_CNT(call_head, call_tail, size); 63 if (tmp >= max) { 64 _leave(" = -ENOBUFS [enough %u]", tmp); 65 return -ENOBUFS; 66 } 67 max = tmp + 1; 68 69 head = b->peer_backlog_head; 70 tail = READ_ONCE(b->peer_backlog_tail); 71 if (CIRC_CNT(head, tail, size) < max) { 72 struct rxrpc_peer *peer; 73 74 peer = rxrpc_alloc_peer(rx->local, gfp, rxrpc_peer_new_prealloc); 75 if (!peer) 76 return -ENOMEM; 77 b->peer_backlog[head] = peer; 78 smp_store_release(&b->peer_backlog_head, 79 (head + 1) & (size - 1)); 80 } 81 82 head = b->conn_backlog_head; 83 tail = READ_ONCE(b->conn_backlog_tail); 84 if (CIRC_CNT(head, tail, size) < max) { 85 struct rxrpc_connection *conn; 86 87 conn = rxrpc_prealloc_service_connection(rxnet, gfp); 88 if (!conn) 89 return -ENOMEM; 90 b->conn_backlog[head] = conn; 91 smp_store_release(&b->conn_backlog_head, 92 (head + 1) & (size - 1)); 93 } 94 95 /* Now it gets complicated, because calls get registered with the 96 * socket here, with a user ID preassigned by the user. 97 */ 98 call = rxrpc_alloc_call(rx, gfp, debug_id); 99 if (!call) 100 return -ENOMEM; 101 call->flags |= (1 << RXRPC_CALL_IS_SERVICE); 102 rxrpc_set_call_state(call, RXRPC_CALL_SERVER_PREALLOC); 103 __set_bit(RXRPC_CALL_EV_INITIAL_PING, &call->events); 104 105 trace_rxrpc_call(call->debug_id, refcount_read(&call->ref), 106 user_call_ID, rxrpc_call_new_prealloc_service); 107 108 write_lock(&rx->call_lock); 109 110 /* Check the user ID isn't already in use */ 111 pp = &rx->calls.rb_node; 112 parent = NULL; 113 while (*pp) { 114 parent = *pp; 115 xcall = rb_entry(parent, struct rxrpc_call, sock_node); 116 if (user_call_ID < xcall->user_call_ID) 117 pp = &(*pp)->rb_left; 118 else if (user_call_ID > xcall->user_call_ID) 119 pp = &(*pp)->rb_right; 120 else 121 goto id_in_use; 122 } 123 124 call->user_call_ID = user_call_ID; 125 call->notify_rx = notify_rx; 126 if (user_attach_call) { 127 rxrpc_get_call(call, rxrpc_call_get_kernel_service); 128 user_attach_call(call, user_call_ID); 129 } 130 131 rxrpc_get_call(call, rxrpc_call_get_userid); 132 rb_link_node(&call->sock_node, parent, pp); 133 rb_insert_color(&call->sock_node, &rx->calls); 134 set_bit(RXRPC_CALL_HAS_USERID, &call->flags); 135 136 list_add(&call->sock_link, &rx->sock_calls); 137 138 write_unlock(&rx->call_lock); 139 140 rxnet = call->rxnet; 141 spin_lock(&rxnet->call_lock); 142 list_add_tail_rcu(&call->link, &rxnet->calls); 143 spin_unlock(&rxnet->call_lock); 144 145 b->call_backlog[call_head] = call; 146 smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1)); 147 _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID); 148 return 0; 149 150 id_in_use: 151 write_unlock(&rx->call_lock); 152 rxrpc_cleanup_call(call); 153 _leave(" = -EBADSLT"); 154 return -EBADSLT; 155 } 156 157 /* 158 * Allocate the preallocation buffers for incoming service calls. These must 159 * be charged manually. 160 */ 161 int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp) 162 { 163 struct rxrpc_backlog *b = rx->backlog; 164 165 if (!b) { 166 b = kzalloc(sizeof(struct rxrpc_backlog), gfp); 167 if (!b) 168 return -ENOMEM; 169 rx->backlog = b; 170 } 171 172 return 0; 173 } 174 175 /* 176 * Discard the preallocation on a service. 177 */ 178 void rxrpc_discard_prealloc(struct rxrpc_sock *rx) 179 { 180 struct rxrpc_backlog *b = rx->backlog; 181 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); 182 unsigned int size = RXRPC_BACKLOG_MAX, head, tail; 183 184 if (!b) 185 return; 186 rx->backlog = NULL; 187 188 /* Make sure that there aren't any incoming calls in progress before we 189 * clear the preallocation buffers. 190 */ 191 spin_lock(&rx->incoming_lock); 192 spin_unlock(&rx->incoming_lock); 193 194 head = b->peer_backlog_head; 195 tail = b->peer_backlog_tail; 196 while (CIRC_CNT(head, tail, size) > 0) { 197 struct rxrpc_peer *peer = b->peer_backlog[tail]; 198 rxrpc_put_local(peer->local, rxrpc_local_put_prealloc_peer); 199 kfree(peer); 200 tail = (tail + 1) & (size - 1); 201 } 202 203 head = b->conn_backlog_head; 204 tail = b->conn_backlog_tail; 205 while (CIRC_CNT(head, tail, size) > 0) { 206 struct rxrpc_connection *conn = b->conn_backlog[tail]; 207 write_lock(&rxnet->conn_lock); 208 list_del(&conn->link); 209 list_del(&conn->proc_link); 210 write_unlock(&rxnet->conn_lock); 211 kfree(conn); 212 if (atomic_dec_and_test(&rxnet->nr_conns)) 213 wake_up_var(&rxnet->nr_conns); 214 tail = (tail + 1) & (size - 1); 215 } 216 217 head = b->call_backlog_head; 218 tail = b->call_backlog_tail; 219 while (CIRC_CNT(head, tail, size) > 0) { 220 struct rxrpc_call *call = b->call_backlog[tail]; 221 rcu_assign_pointer(call->socket, rx); 222 if (rx->discard_new_call) { 223 _debug("discard %lx", call->user_call_ID); 224 rx->discard_new_call(call, call->user_call_ID); 225 if (call->notify_rx) 226 call->notify_rx = rxrpc_dummy_notify; 227 rxrpc_put_call(call, rxrpc_call_put_kernel); 228 } 229 rxrpc_call_completed(call); 230 rxrpc_release_call(rx, call); 231 rxrpc_put_call(call, rxrpc_call_put_discard_prealloc); 232 tail = (tail + 1) & (size - 1); 233 } 234 235 kfree(b); 236 } 237 238 /* 239 * Allocate a new incoming call from the prealloc pool, along with a connection 240 * and a peer as necessary. 241 */ 242 static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx, 243 struct rxrpc_local *local, 244 struct rxrpc_peer *peer, 245 struct rxrpc_connection *conn, 246 const struct rxrpc_security *sec, 247 struct sockaddr_rxrpc *peer_srx, 248 struct sk_buff *skb) 249 { 250 struct rxrpc_backlog *b = rx->backlog; 251 struct rxrpc_call *call; 252 unsigned short call_head, conn_head, peer_head; 253 unsigned short call_tail, conn_tail, peer_tail; 254 unsigned short call_count, conn_count; 255 256 /* #calls >= #conns >= #peers must hold true. */ 257 call_head = smp_load_acquire(&b->call_backlog_head); 258 call_tail = b->call_backlog_tail; 259 call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX); 260 conn_head = smp_load_acquire(&b->conn_backlog_head); 261 conn_tail = b->conn_backlog_tail; 262 conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX); 263 ASSERTCMP(conn_count, >=, call_count); 264 peer_head = smp_load_acquire(&b->peer_backlog_head); 265 peer_tail = b->peer_backlog_tail; 266 ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=, 267 conn_count); 268 269 if (call_count == 0) 270 return NULL; 271 272 if (!conn) { 273 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_service_conn)) 274 peer = NULL; 275 if (!peer) { 276 peer = b->peer_backlog[peer_tail]; 277 peer->srx = *peer_srx; 278 b->peer_backlog[peer_tail] = NULL; 279 smp_store_release(&b->peer_backlog_tail, 280 (peer_tail + 1) & 281 (RXRPC_BACKLOG_MAX - 1)); 282 283 rxrpc_new_incoming_peer(local, peer); 284 } 285 286 /* Now allocate and set up the connection */ 287 conn = b->conn_backlog[conn_tail]; 288 b->conn_backlog[conn_tail] = NULL; 289 smp_store_release(&b->conn_backlog_tail, 290 (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); 291 conn->local = rxrpc_get_local(local, rxrpc_local_get_prealloc_conn); 292 conn->peer = peer; 293 rxrpc_see_connection(conn, rxrpc_conn_see_new_service_conn); 294 rxrpc_new_incoming_connection(rx, conn, sec, skb); 295 } else { 296 rxrpc_get_connection(conn, rxrpc_conn_get_service_conn); 297 atomic_inc(&conn->active); 298 } 299 300 /* And now we can allocate and set up a new call */ 301 call = b->call_backlog[call_tail]; 302 b->call_backlog[call_tail] = NULL; 303 smp_store_release(&b->call_backlog_tail, 304 (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1)); 305 306 rxrpc_see_call(call, rxrpc_call_see_accept); 307 call->local = rxrpc_get_local(conn->local, rxrpc_local_get_call); 308 call->conn = conn; 309 call->security = conn->security; 310 call->security_ix = conn->security_ix; 311 call->peer = rxrpc_get_peer(conn->peer, rxrpc_peer_get_accept); 312 call->dest_srx = peer->srx; 313 call->cong_ssthresh = call->peer->cong_ssthresh; 314 call->tx_last_sent = ktime_get_real(); 315 return call; 316 } 317 318 /* 319 * Set up a new incoming call. Called from the I/O thread. 320 * 321 * If this is for a kernel service, when we allocate the call, it will have 322 * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the 323 * retainer ref obtained from the backlog buffer. Prealloc calls for userspace 324 * services only have the ref from the backlog buffer. 325 * 326 * If we want to report an error, we mark the skb with the packet type and 327 * abort code and return false. 328 */ 329 bool rxrpc_new_incoming_call(struct rxrpc_local *local, 330 struct rxrpc_peer *peer, 331 struct rxrpc_connection *conn, 332 struct sockaddr_rxrpc *peer_srx, 333 struct sk_buff *skb) 334 { 335 const struct rxrpc_security *sec = NULL; 336 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 337 struct rxrpc_call *call = NULL; 338 struct rxrpc_sock *rx; 339 340 _enter(""); 341 342 /* Don't set up a call for anything other than a DATA packet. */ 343 if (sp->hdr.type != RXRPC_PACKET_TYPE_DATA) 344 return rxrpc_protocol_error(skb, rxrpc_eproto_no_service_call); 345 346 read_lock(&local->services_lock); 347 348 /* Weed out packets to services we're not offering. Packets that would 349 * begin a call are explicitly rejected and the rest are just 350 * discarded. 351 */ 352 rx = local->service; 353 if (!rx || (sp->hdr.serviceId != rx->srx.srx_service && 354 sp->hdr.serviceId != rx->second_service) 355 ) { 356 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA && 357 sp->hdr.seq == 1) 358 goto unsupported_service; 359 goto discard; 360 } 361 362 if (!conn) { 363 sec = rxrpc_get_incoming_security(rx, skb); 364 if (!sec) 365 goto unsupported_security; 366 } 367 368 spin_lock(&rx->incoming_lock); 369 if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED || 370 rx->sk.sk_state == RXRPC_CLOSE) { 371 rxrpc_direct_abort(skb, rxrpc_abort_shut_down, 372 RX_INVALID_OPERATION, -ESHUTDOWN); 373 goto no_call; 374 } 375 376 call = rxrpc_alloc_incoming_call(rx, local, peer, conn, sec, peer_srx, 377 skb); 378 if (!call) { 379 skb->mark = RXRPC_SKB_MARK_REJECT_BUSY; 380 goto no_call; 381 } 382 383 trace_rxrpc_receive(call, rxrpc_receive_incoming, 384 sp->hdr.serial, sp->hdr.seq); 385 386 /* Make the call live. */ 387 rxrpc_incoming_call(rx, call, skb); 388 conn = call->conn; 389 390 if (rx->notify_new_call) 391 rx->notify_new_call(&rx->sk, call, call->user_call_ID); 392 393 spin_lock(&conn->state_lock); 394 if (conn->state == RXRPC_CONN_SERVICE_UNSECURED) { 395 conn->state = RXRPC_CONN_SERVICE_CHALLENGING; 396 set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events); 397 rxrpc_queue_conn(call->conn, rxrpc_conn_queue_challenge); 398 } 399 spin_unlock(&conn->state_lock); 400 401 spin_unlock(&rx->incoming_lock); 402 read_unlock(&local->services_lock); 403 404 if (hlist_unhashed(&call->error_link)) { 405 spin_lock(&call->peer->lock); 406 hlist_add_head(&call->error_link, &call->peer->error_targets); 407 spin_unlock(&call->peer->lock); 408 } 409 410 _leave(" = %p{%d}", call, call->debug_id); 411 rxrpc_input_call_event(call, skb); 412 rxrpc_put_call(call, rxrpc_call_put_input); 413 return true; 414 415 unsupported_service: 416 read_unlock(&local->services_lock); 417 return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered, 418 RX_INVALID_OPERATION, -EOPNOTSUPP); 419 unsupported_security: 420 read_unlock(&local->services_lock); 421 return rxrpc_direct_abort(skb, rxrpc_abort_service_not_offered, 422 RX_INVALID_OPERATION, -EKEYREJECTED); 423 no_call: 424 spin_unlock(&rx->incoming_lock); 425 read_unlock(&local->services_lock); 426 _leave(" = f [%u]", skb->mark); 427 return false; 428 discard: 429 read_unlock(&local->services_lock); 430 return true; 431 } 432 433 /* 434 * Charge up socket with preallocated calls, attaching user call IDs. 435 */ 436 int rxrpc_user_charge_accept(struct rxrpc_sock *rx, unsigned long user_call_ID) 437 { 438 struct rxrpc_backlog *b = rx->backlog; 439 440 if (rx->sk.sk_state == RXRPC_CLOSE) 441 return -ESHUTDOWN; 442 443 return rxrpc_service_prealloc_one(rx, b, NULL, NULL, user_call_ID, 444 GFP_KERNEL, 445 atomic_inc_return(&rxrpc_debug_id)); 446 } 447 448 /* 449 * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls 450 * @sock: The socket on which to preallocate 451 * @notify_rx: Event notification function for the call 452 * @user_attach_call: Func to attach call to user_call_ID 453 * @user_call_ID: The tag to attach to the preallocated call 454 * @gfp: The allocation conditions. 455 * @debug_id: The tracing debug ID. 456 * 457 * Charge up the socket with preallocated calls, each with a user ID. A 458 * function should be provided to effect the attachment from the user's side. 459 * The user is given a ref to hold on the call. 460 * 461 * Note that the call may be come connected before this function returns. 462 */ 463 int rxrpc_kernel_charge_accept(struct socket *sock, 464 rxrpc_notify_rx_t notify_rx, 465 rxrpc_user_attach_call_t user_attach_call, 466 unsigned long user_call_ID, gfp_t gfp, 467 unsigned int debug_id) 468 { 469 struct rxrpc_sock *rx = rxrpc_sk(sock->sk); 470 struct rxrpc_backlog *b = rx->backlog; 471 472 if (sock->sk->sk_state == RXRPC_CLOSE) 473 return -ESHUTDOWN; 474 475 return rxrpc_service_prealloc_one(rx, b, notify_rx, 476 user_attach_call, user_call_ID, 477 gfp, debug_id); 478 } 479 EXPORT_SYMBOL(rxrpc_kernel_charge_accept); 480