net/rxrpc/conn_event.c

   1 /* connection-level event handling
   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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include <net/ip.h>
  21 #include "ar-internal.h"
  22
  23 /*
  24  * Retransmit terminal ACK or ABORT of the previous call.
  25  */
  26 static void rxrpc_conn_retransmit_call(struct rxrpc_connection *conn,
  27                                        struct sk_buff *skb,
  28                                        unsigned int channel)
  29 {
  30         struct rxrpc_skb_priv *sp = skb ? rxrpc_skb(skb) : NULL;
  31         struct rxrpc_channel *chan;
  32         struct msghdr msg;
  33         struct kvec iov[3];
  34         struct {
  35                 struct rxrpc_wire_header whdr;
  36                 union {
  37                         __be32 abort_code;
  38                         struct rxrpc_ackpacket ack;
  39                 };
  40         } __attribute__((packed)) pkt;
  41         struct rxrpc_ackinfo ack_info;
  42         size_t len;
  43         int ioc;
  44         u32 serial, mtu, call_id, padding;
  45
  46         _enter("%d", conn->debug_id);
  47
  48         chan = &conn->channels[channel];
  49
  50         /* If the last call got moved on whilst we were waiting to run, just
  51          * ignore this packet.
  52          */
  53         call_id = READ_ONCE(chan->last_call);
  54         /* Sync with __rxrpc_disconnect_call() */
  55         smp_rmb();
  56         if (skb && call_id != sp->hdr.callNumber)
  57                 return;
  58
  59         msg.msg_name    = &conn->params.peer->srx.transport;
  60         msg.msg_namelen = conn->params.peer->srx.transport_len;
  61         msg.msg_control = NULL;
  62         msg.msg_controllen = 0;
  63         msg.msg_flags   = 0;
  64
  65         iov[0].iov_base = &pkt;
  66         iov[0].iov_len  = sizeof(pkt.whdr);
  67         iov[1].iov_base = &padding;
  68         iov[1].iov_len  = 3;
  69         iov[2].iov_base = &ack_info;
  70         iov[2].iov_len  = sizeof(ack_info);
  71
  72         pkt.whdr.epoch          = htonl(conn->proto.epoch);
  73         pkt.whdr.cid            = htonl(conn->proto.cid);
  74         pkt.whdr.callNumber     = htonl(call_id);
  75         pkt.whdr.seq            = 0;
  76         pkt.whdr.type           = chan->last_type;
  77         pkt.whdr.flags          = conn->out_clientflag;
  78         pkt.whdr.userStatus     = 0;
  79         pkt.whdr.securityIndex  = conn->security_ix;
  80         pkt.whdr._rsvd          = 0;
  81         pkt.whdr.serviceId      = htons(conn->service_id);
  82
  83         len = sizeof(pkt.whdr);
  84         switch (chan->last_type) {
  85         case RXRPC_PACKET_TYPE_ABORT:
  86                 pkt.abort_code  = htonl(chan->last_abort);
  87                 iov[0].iov_len += sizeof(pkt.abort_code);
  88                 len += sizeof(pkt.abort_code);
  89                 ioc = 1;
  90                 break;
  91
  92         case RXRPC_PACKET_TYPE_ACK:
  93                 mtu = conn->params.peer->if_mtu;
  94                 mtu -= conn->params.peer->hdrsize;
  95                 pkt.ack.bufferSpace     = 0;
  96                 pkt.ack.maxSkew         = htons(skb ? skb->priority : 0);
  97                 pkt.ack.firstPacket     = htonl(chan->last_seq + 1);
  98                 pkt.ack.previousPacket  = htonl(chan->last_seq);
  99                 pkt.ack.serial          = htonl(skb ? sp->hdr.serial : 0);
 100                 pkt.ack.reason          = skb ? RXRPC_ACK_DUPLICATE : RXRPC_ACK_IDLE;
 101                 pkt.ack.nAcks           = 0;
 102                 ack_info.rxMTU          = htonl(rxrpc_rx_mtu);
 103                 ack_info.maxMTU         = htonl(mtu);
 104                 ack_info.rwind          = htonl(rxrpc_rx_window_size);
 105                 ack_info.jumbo_max      = htonl(rxrpc_rx_jumbo_max);
 106                 pkt.whdr.flags          |= RXRPC_SLOW_START_OK;
 107                 padding                 = 0;
 108                 iov[0].iov_len += sizeof(pkt.ack);
 109                 len += sizeof(pkt.ack) + 3 + sizeof(ack_info);
 110                 ioc = 3;
 111                 break;
 112
 113         default:
 114                 return;
 115         }
 116
 117         /* Resync with __rxrpc_disconnect_call() and check that the last call
 118          * didn't get advanced whilst we were filling out the packets.
 119          */
 120         smp_rmb();
 121         if (READ_ONCE(chan->last_call) != call_id)
 122                 return;
 123
 124         serial = atomic_inc_return(&conn->serial);
 125         pkt.whdr.serial = htonl(serial);
 126
 127         switch (chan->last_type) {
 128         case RXRPC_PACKET_TYPE_ABORT:
 129                 _proto("Tx ABORT %%%u { %d } [re]", serial, conn->local_abort);
 130                 break;
 131         case RXRPC_PACKET_TYPE_ACK:
 132                 trace_rxrpc_tx_ack(NULL, serial, chan->last_seq, 0,
 133                                    RXRPC_ACK_DUPLICATE, 0);
 134                 _proto("Tx ACK %%%u [re]", serial);
 135                 break;
 136         }
 137
 138         kernel_sendmsg(conn->params.local->socket, &msg, iov, ioc, len);
 139         conn->params.peer->last_tx_at = ktime_get_real();
 140         _leave("");
 141         return;
 142 }
 143
 144 /*
 145  * pass a connection-level abort onto all calls on that connection
 146  */
 147 static void rxrpc_abort_calls(struct rxrpc_connection *conn,
 148                               enum rxrpc_call_completion compl,
 149                               u32 abort_code, int error)
 150 {
 151         struct rxrpc_call *call;
 152         int i;
 153
 154         _enter("{%d},%x", conn->debug_id, abort_code);
 155
 156         spin_lock(&conn->channel_lock);
 157
 158         for (i = 0; i < RXRPC_MAXCALLS; i++) {
 159                 call = rcu_dereference_protected(
 160                         conn->channels[i].call,
 161                         lockdep_is_held(&conn->channel_lock));
 162                 if (call) {
 163                         if (compl == RXRPC_CALL_LOCALLY_ABORTED)
 164                                 trace_rxrpc_abort(call->debug_id,
 165                                                   "CON", call->cid,
 166                                                   call->call_id, 0,
 167                                                   abort_code, error);
 168                         if (rxrpc_set_call_completion(call, compl,
 169                                                       abort_code, error))
 170                                 rxrpc_notify_socket(call);
 171                 }
 172         }
 173
 174         spin_unlock(&conn->channel_lock);
 175         _leave("");
 176 }
 177
 178 /*
 179  * generate a connection-level abort
 180  */
 181 static int rxrpc_abort_connection(struct rxrpc_connection *conn,
 182                                   int error, u32 abort_code)
 183 {
 184         struct rxrpc_wire_header whdr;
 185         struct msghdr msg;
 186         struct kvec iov[2];
 187         __be32 word;
 188         size_t len;
 189         u32 serial;
 190         int ret;
 191
 192         _enter("%d,,%u,%u", conn->debug_id, error, abort_code);
 193
 194         /* generate a connection-level abort */
 195         spin_lock_bh(&conn->state_lock);
 196         if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 197                 spin_unlock_bh(&conn->state_lock);
 198                 _leave(" = 0 [already dead]");
 199                 return 0;
 200         }
 201
 202         conn->state = RXRPC_CONN_LOCALLY_ABORTED;
 203         spin_unlock_bh(&conn->state_lock);
 204
 205         rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, abort_code, error);
 206
 207         msg.msg_name    = &conn->params.peer->srx.transport;
 208         msg.msg_namelen = conn->params.peer->srx.transport_len;
 209         msg.msg_control = NULL;
 210         msg.msg_controllen = 0;
 211         msg.msg_flags   = 0;
 212
 213         whdr.epoch      = htonl(conn->proto.epoch);
 214         whdr.cid        = htonl(conn->proto.cid);
 215         whdr.callNumber = 0;
 216         whdr.seq        = 0;
 217         whdr.type       = RXRPC_PACKET_TYPE_ABORT;
 218         whdr.flags      = conn->out_clientflag;
 219         whdr.userStatus = 0;
 220         whdr.securityIndex = conn->security_ix;
 221         whdr._rsvd      = 0;
 222         whdr.serviceId  = htons(conn->service_id);
 223
 224         word            = htonl(conn->local_abort);
 225
 226         iov[0].iov_base = &whdr;
 227         iov[0].iov_len  = sizeof(whdr);
 228         iov[1].iov_base = &word;
 229         iov[1].iov_len  = sizeof(word);
 230
 231         len = iov[0].iov_len + iov[1].iov_len;
 232
 233         serial = atomic_inc_return(&conn->serial);
 234         whdr.serial = htonl(serial);
 235         _proto("Tx CONN ABORT %%%u { %d }", serial, conn->local_abort);
 236
 237         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 238         if (ret < 0) {
 239                 _debug("sendmsg failed: %d", ret);
 240                 return -EAGAIN;
 241         }
 242
 243         conn->params.peer->last_tx_at = ktime_get_real();
 244
 245         _leave(" = 0");
 246         return 0;
 247 }
 248
 249 /*
 250  * mark a call as being on a now-secured channel
 251  * - must be called with BH's disabled.
 252  */
 253 static void rxrpc_call_is_secure(struct rxrpc_call *call)
 254 {
 255         _enter("%p", call);
 256         if (call) {
 257                 write_lock_bh(&call->state_lock);
 258                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
 259                         call->state = RXRPC_CALL_SERVER_ACCEPTING;
 260                         rxrpc_notify_socket(call);
 261                 }
 262                 write_unlock_bh(&call->state_lock);
 263         }
 264 }
 265
 266 /*
 267  * connection-level Rx packet processor
 268  */
 269 static int rxrpc_process_event(struct rxrpc_connection *conn,
 270                                struct sk_buff *skb,
 271                                u32 *_abort_code)
 272 {
 273         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 274         __be32 wtmp;
 275         u32 abort_code;
 276         int loop, ret;
 277
 278         if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
 279                 _leave(" = -ECONNABORTED [%u]", conn->state);
 280                 return -ECONNABORTED;
 281         }
 282
 283         _enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, sp->hdr.serial);
 284
 285         switch (sp->hdr.type) {
 286         case RXRPC_PACKET_TYPE_DATA:
 287         case RXRPC_PACKET_TYPE_ACK:
 288                 rxrpc_conn_retransmit_call(conn, skb,
 289                                            sp->hdr.cid & RXRPC_CHANNELMASK);
 290                 return 0;
 291
 292         case RXRPC_PACKET_TYPE_BUSY:
 293                 /* Just ignore BUSY packets for now. */
 294                 return 0;
 295
 296         case RXRPC_PACKET_TYPE_ABORT:
 297                 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
 298                                   &wtmp, sizeof(wtmp)) < 0) {
 299                         trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
 300                                               tracepoint_string("bad_abort"));
 301                         return -EPROTO;
 302                 }
 303                 abort_code = ntohl(wtmp);
 304                 _proto("Rx ABORT %%%u { ac=%d }", sp->hdr.serial, abort_code);
 305
 306                 conn->state = RXRPC_CONN_REMOTELY_ABORTED;
 307                 rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED,
 308                                   abort_code, -ECONNABORTED);
 309                 return -ECONNABORTED;
 310
 311         case RXRPC_PACKET_TYPE_CHALLENGE:
 312                 return conn->security->respond_to_challenge(conn, skb,
 313                                                             _abort_code);
 314
 315         case RXRPC_PACKET_TYPE_RESPONSE:
 316                 ret = conn->security->verify_response(conn, skb, _abort_code);
 317                 if (ret < 0)
 318                         return ret;
 319
 320                 ret = conn->security->init_connection_security(conn);
 321                 if (ret < 0)
 322                         return ret;
 323
 324                 ret = conn->security->prime_packet_security(conn);
 325                 if (ret < 0)
 326                         return ret;
 327
 328                 spin_lock(&conn->channel_lock);
 329                 spin_lock(&conn->state_lock);
 330
 331                 if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
 332                         conn->state = RXRPC_CONN_SERVICE;
 333                         spin_unlock(&conn->state_lock);
 334                         for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
 335                                 rxrpc_call_is_secure(
 336                                         rcu_dereference_protected(
 337                                                 conn->channels[loop].call,
 338                                                 lockdep_is_held(&conn->channel_lock)));
 339                 } else {
 340                         spin_unlock(&conn->state_lock);
 341                 }
 342
 343                 spin_unlock(&conn->channel_lock);
 344                 return 0;
 345
 346         default:
 347                 trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
 348                                       tracepoint_string("bad_conn_pkt"));
 349                 return -EPROTO;
 350         }
 351 }
 352
 353 /*
 354  * set up security and issue a challenge
 355  */
 356 static void rxrpc_secure_connection(struct rxrpc_connection *conn)
 357 {
 358         u32 abort_code;
 359         int ret;
 360
 361         _enter("{%d}", conn->debug_id);
 362
 363         ASSERT(conn->security_ix != 0);
 364
 365         if (!conn->params.key) {
 366                 _debug("set up security");
 367                 ret = rxrpc_init_server_conn_security(conn);
 368                 switch (ret) {
 369                 case 0:
 370                         break;
 371                 case -ENOENT:
 372                         abort_code = RX_CALL_DEAD;
 373                         goto abort;
 374                 default:
 375                         abort_code = RXKADNOAUTH;
 376                         goto abort;
 377                 }
 378         }
 379
 380         if (conn->security->issue_challenge(conn) < 0) {
 381                 abort_code = RX_CALL_DEAD;
 382                 ret = -ENOMEM;
 383                 goto abort;
 384         }
 385
 386         _leave("");
 387         return;
 388
 389 abort:
 390         _debug("abort %d, %d", ret, abort_code);
 391         rxrpc_abort_connection(conn, ret, abort_code);
 392         _leave(" [aborted]");
 393 }
 394
 395 /*
 396  * Process delayed final ACKs that we haven't subsumed into a subsequent call.
 397  */
 398 static void rxrpc_process_delayed_final_acks(struct rxrpc_connection *conn)
 399 {
 400         unsigned long j = jiffies, next_j;
 401         unsigned int channel;
 402         bool set;
 403
 404 again:
 405         next_j = j + LONG_MAX;
 406         set = false;
 407         for (channel = 0; channel < RXRPC_MAXCALLS; channel++) {
 408                 struct rxrpc_channel *chan = &conn->channels[channel];
 409                 unsigned long ack_at;
 410
 411                 if (!test_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags))
 412                         continue;
 413
 414                 smp_rmb(); /* vs rxrpc_disconnect_client_call */
 415                 ack_at = READ_ONCE(chan->final_ack_at);
 416
 417                 if (time_before(j, ack_at)) {
 418                         if (time_before(ack_at, next_j)) {
 419                                 next_j = ack_at;
 420                                 set = true;
 421                         }
 422                         continue;
 423                 }
 424
 425                 if (test_and_clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel,
 426                                        &conn->flags))
 427                         rxrpc_conn_retransmit_call(conn, NULL, channel);
 428         }
 429
 430         j = jiffies;
 431         if (time_before_eq(next_j, j))
 432                 goto again;
 433         if (set)
 434                 rxrpc_reduce_conn_timer(conn, next_j);
 435 }
 436
 437 /*
 438  * connection-level event processor
 439  */
 440 void rxrpc_process_connection(struct work_struct *work)
 441 {
 442         struct rxrpc_connection *conn =
 443                 container_of(work, struct rxrpc_connection, processor);
 444         struct sk_buff *skb;
 445         u32 abort_code = RX_PROTOCOL_ERROR;
 446         int ret;
 447
 448         rxrpc_see_connection(conn);
 449
 450         if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
 451                 rxrpc_secure_connection(conn);
 452
 453         /* Process delayed ACKs whose time has come. */
 454         if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
 455                 rxrpc_process_delayed_final_acks(conn);
 456
 457         /* go through the conn-level event packets, releasing the ref on this
 458          * connection that each one has when we've finished with it */
 459         while ((skb = skb_dequeue(&conn->rx_queue))) {
 460                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 461                 ret = rxrpc_process_event(conn, skb, &abort_code);
 462                 switch (ret) {
 463                 case -EPROTO:
 464                 case -EKEYEXPIRED:
 465                 case -EKEYREJECTED:
 466                         goto protocol_error;
 467                 case -ENOMEM:
 468                 case -EAGAIN:
 469                         goto requeue_and_leave;
 470                 case -ECONNABORTED:
 471                 default:
 472                         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 473                         break;
 474                 }
 475         }
 476
 477 out:
 478         rxrpc_put_connection(conn);
 479         _leave("");
 480         return;
 481
 482 requeue_and_leave:
 483         skb_queue_head(&conn->rx_queue, skb);
 484         goto out;
 485
 486 protocol_error:
 487         if (rxrpc_abort_connection(conn, ret, abort_code) < 0)
 488                 goto requeue_and_leave;
 489         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 490         goto out;
 491 }