net/rxrpc/output.c

   1 /* RxRPC packet transmission
   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/net.h>
  15 #include <linux/gfp.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/export.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 struct rxrpc_ack_buffer {
  23         struct rxrpc_wire_header whdr;
  24         struct rxrpc_ackpacket ack;
  25         u8 acks[255];
  26         u8 pad[3];
  27         struct rxrpc_ackinfo ackinfo;
  28 };
  29
  30 struct rxrpc_abort_buffer {
  31         struct rxrpc_wire_header whdr;
  32         __be32 abort_code;
  33 };
  34
  35 /*
  36  * Fill out an ACK packet.
  37  */
  38 static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
  39                                  struct rxrpc_ack_buffer *pkt,
  40                                  rxrpc_seq_t *_hard_ack,
  41                                  rxrpc_seq_t *_top,
  42                                  u8 reason)
  43 {
  44         rxrpc_serial_t serial;
  45         rxrpc_seq_t hard_ack, top, seq;
  46         int ix;
  47         u32 mtu, jmax;
  48         u8 *ackp = pkt->acks;
  49
  50         /* Barrier against rxrpc_input_data(). */
  51         serial = call->ackr_serial;
  52         hard_ack = READ_ONCE(call->rx_hard_ack);
  53         top = smp_load_acquire(&call->rx_top);
  54         *_hard_ack = hard_ack;
  55         *_top = top;
  56
  57         pkt->ack.bufferSpace    = htons(8);
  58         pkt->ack.maxSkew        = htons(call->ackr_skew);
  59         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  60         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  61         pkt->ack.serial         = htonl(serial);
  62         pkt->ack.reason         = reason;
  63         pkt->ack.nAcks          = top - hard_ack;
  64
  65         if (reason == RXRPC_ACK_PING)
  66                 pkt->whdr.flags |= RXRPC_REQUEST_ACK;
  67
  68         if (after(top, hard_ack)) {
  69                 seq = hard_ack + 1;
  70                 do {
  71                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  72                         if (call->rxtx_buffer[ix])
  73                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  74                         else
  75                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  76                         seq++;
  77                 } while (before_eq(seq, top));
  78         }
  79
  80         mtu = call->conn->params.peer->if_mtu;
  81         mtu -= call->conn->params.peer->hdrsize;
  82         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
  83         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
  84         pkt->ackinfo.maxMTU     = htonl(mtu);
  85         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
  86         pkt->ackinfo.jumbo_max  = htonl(jmax);
  87
  88         *ackp++ = 0;
  89         *ackp++ = 0;
  90         *ackp++ = 0;
  91         return top - hard_ack + 3;
  92 }
  93
  94 /*
  95  * Send an ACK call packet.
  96  */
  97 int rxrpc_send_ack_packet(struct rxrpc_call *call, bool ping)
  98 {
  99         struct rxrpc_connection *conn;
 100         struct rxrpc_ack_buffer *pkt;
 101         struct msghdr msg;
 102         struct kvec iov[2];
 103         rxrpc_serial_t serial;
 104         rxrpc_seq_t hard_ack, top;
 105         size_t len, n;
 106         int ret;
 107         u8 reason;
 108
 109         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 110                 return -ECONNRESET;
 111
 112         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 113         if (!pkt)
 114                 return -ENOMEM;
 115
 116         conn = call->conn;
 117
 118         msg.msg_name    = &call->peer->srx.transport;
 119         msg.msg_namelen = call->peer->srx.transport_len;
 120         msg.msg_control = NULL;
 121         msg.msg_controllen = 0;
 122         msg.msg_flags   = 0;
 123
 124         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 125         pkt->whdr.cid           = htonl(call->cid);
 126         pkt->whdr.callNumber    = htonl(call->call_id);
 127         pkt->whdr.seq           = 0;
 128         pkt->whdr.type          = RXRPC_PACKET_TYPE_ACK;
 129         pkt->whdr.flags         = RXRPC_SLOW_START_OK | conn->out_clientflag;
 130         pkt->whdr.userStatus    = 0;
 131         pkt->whdr.securityIndex = call->security_ix;
 132         pkt->whdr._rsvd         = 0;
 133         pkt->whdr.serviceId     = htons(call->service_id);
 134
 135         spin_lock_bh(&call->lock);
 136         if (ping) {
 137                 reason = RXRPC_ACK_PING;
 138         } else {
 139                 reason = call->ackr_reason;
 140                 if (!call->ackr_reason) {
 141                         spin_unlock_bh(&call->lock);
 142                         ret = 0;
 143                         goto out;
 144                 }
 145                 call->ackr_reason = 0;
 146         }
 147         n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top, reason);
 148
 149         spin_unlock_bh(&call->lock);
 150
 151         iov[0].iov_base = pkt;
 152         iov[0].iov_len  = sizeof(pkt->whdr) + sizeof(pkt->ack) + n;
 153         iov[1].iov_base = &pkt->ackinfo;
 154         iov[1].iov_len  = sizeof(pkt->ackinfo);
 155         len = iov[0].iov_len + iov[1].iov_len;
 156
 157         serial = atomic_inc_return(&conn->serial);
 158         pkt->whdr.serial = htonl(serial);
 159         trace_rxrpc_tx_ack(call, serial,
 160                            ntohl(pkt->ack.firstPacket),
 161                            ntohl(pkt->ack.serial),
 162                            pkt->ack.reason, pkt->ack.nAcks);
 163
 164         if (ping) {
 165                 call->ping_serial = serial;
 166                 smp_wmb();
 167                 /* We need to stick a time in before we send the packet in case
 168                  * the reply gets back before kernel_sendmsg() completes - but
 169                  * asking UDP to send the packet can take a relatively long
 170                  * time, so we update the time after, on the assumption that
 171                  * the packet transmission is more likely to happen towards the
 172                  * end of the kernel_sendmsg() call.
 173                  */
 174                 call->ping_time = ktime_get_real();
 175                 set_bit(RXRPC_CALL_PINGING, &call->flags);
 176                 trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
 177         }
 178
 179         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 180         if (ping)
 181                 call->ping_time = ktime_get_real();
 182
 183         if (call->state < RXRPC_CALL_COMPLETE) {
 184                 if (ret < 0) {
 185                         if (ping)
 186                                 clear_bit(RXRPC_CALL_PINGING, &call->flags);
 187                         rxrpc_propose_ACK(call, pkt->ack.reason,
 188                                           ntohs(pkt->ack.maxSkew),
 189                                           ntohl(pkt->ack.serial),
 190                                           true, true,
 191                                           rxrpc_propose_ack_retry_tx);
 192                 } else {
 193                         spin_lock_bh(&call->lock);
 194                         if (after(hard_ack, call->ackr_consumed))
 195                                 call->ackr_consumed = hard_ack;
 196                         if (after(top, call->ackr_seen))
 197                                 call->ackr_seen = top;
 198                         spin_unlock_bh(&call->lock);
 199                 }
 200         }
 201
 202 out:
 203         kfree(pkt);
 204         return ret;
 205 }
 206
 207 /*
 208  * Send an ABORT call packet.
 209  */
 210 int rxrpc_send_abort_packet(struct rxrpc_call *call)
 211 {
 212         struct rxrpc_connection *conn;
 213         struct rxrpc_abort_buffer pkt;
 214         struct msghdr msg;
 215         struct kvec iov[1];
 216         rxrpc_serial_t serial;
 217         int ret;
 218
 219         if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))
 220                 return -ECONNRESET;
 221
 222         conn = call->conn;
 223
 224         msg.msg_name    = &call->peer->srx.transport;
 225         msg.msg_namelen = call->peer->srx.transport_len;
 226         msg.msg_control = NULL;
 227         msg.msg_controllen = 0;
 228         msg.msg_flags   = 0;
 229
 230         pkt.whdr.epoch          = htonl(conn->proto.epoch);
 231         pkt.whdr.cid            = htonl(call->cid);
 232         pkt.whdr.callNumber     = htonl(call->call_id);
 233         pkt.whdr.seq            = 0;
 234         pkt.whdr.type           = RXRPC_PACKET_TYPE_ABORT;
 235         pkt.whdr.flags          = conn->out_clientflag;
 236         pkt.whdr.userStatus     = 0;
 237         pkt.whdr.securityIndex  = call->security_ix;
 238         pkt.whdr._rsvd          = 0;
 239         pkt.whdr.serviceId      = htons(call->service_id);
 240         pkt.abort_code          = htonl(call->abort_code);
 241
 242         iov[0].iov_base = &pkt;
 243         iov[0].iov_len  = sizeof(pkt);
 244
 245         serial = atomic_inc_return(&conn->serial);
 246         pkt.whdr.serial = htonl(serial);
 247
 248         ret = kernel_sendmsg(conn->params.local->socket,
 249                              &msg, iov, 1, sizeof(pkt));
 250
 251         return ret;
 252 }
 253
 254 /*
 255  * send a packet through the transport endpoint
 256  */
 257 int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
 258                            bool retrans)
 259 {
 260         struct rxrpc_connection *conn = call->conn;
 261         struct rxrpc_wire_header whdr;
 262         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 263         struct msghdr msg;
 264         struct kvec iov[2];
 265         rxrpc_serial_t serial;
 266         size_t len;
 267         bool lost = false;
 268         int ret, opt;
 269
 270         _enter(",{%d}", skb->len);
 271
 272         /* Each transmission of a Tx packet needs a new serial number */
 273         serial = atomic_inc_return(&conn->serial);
 274
 275         whdr.epoch      = htonl(conn->proto.epoch);
 276         whdr.cid        = htonl(call->cid);
 277         whdr.callNumber = htonl(call->call_id);
 278         whdr.seq        = htonl(sp->hdr.seq);
 279         whdr.serial     = htonl(serial);
 280         whdr.type       = RXRPC_PACKET_TYPE_DATA;
 281         whdr.flags      = sp->hdr.flags;
 282         whdr.userStatus = 0;
 283         whdr.securityIndex = call->security_ix;
 284         whdr._rsvd      = htons(sp->hdr._rsvd);
 285         whdr.serviceId  = htons(call->service_id);
 286
 287         iov[0].iov_base = &whdr;
 288         iov[0].iov_len = sizeof(whdr);
 289         iov[1].iov_base = skb->head;
 290         iov[1].iov_len = skb->len;
 291         len = iov[0].iov_len + iov[1].iov_len;
 292
 293         msg.msg_name = &call->peer->srx.transport;
 294         msg.msg_namelen = call->peer->srx.transport_len;
 295         msg.msg_control = NULL;
 296         msg.msg_controllen = 0;
 297         msg.msg_flags = 0;
 298
 299         /* If our RTT cache needs working on, request an ACK.  Also request
 300          * ACKs if a DATA packet appears to have been lost.
 301          */
 302         if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
 303             (retrans ||
 304              call->cong_mode == RXRPC_CALL_SLOW_START ||
 305              (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
 306              ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
 307                           ktime_get_real())))
 308                 whdr.flags |= RXRPC_REQUEST_ACK;
 309
 310         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 311                 static int lose;
 312                 if ((lose++ & 7) == 7) {
 313                         ret = 0;
 314                         lost = true;
 315                         goto done;
 316                 }
 317         }
 318
 319         _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
 320
 321         /* send the packet with the don't fragment bit set if we currently
 322          * think it's small enough */
 323         if (iov[1].iov_len >= call->peer->maxdata)
 324                 goto send_fragmentable;
 325
 326         down_read(&conn->params.local->defrag_sem);
 327         /* send the packet by UDP
 328          * - returns -EMSGSIZE if UDP would have to fragment the packet
 329          *   to go out of the interface
 330          *   - in which case, we'll have processed the ICMP error
 331          *     message and update the peer record
 332          */
 333         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
 334
 335         up_read(&conn->params.local->defrag_sem);
 336         if (ret == -EMSGSIZE)
 337                 goto send_fragmentable;
 338
 339 done:
 340         trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
 341                             retrans, lost);
 342         if (ret >= 0) {
 343                 ktime_t now = ktime_get_real();
 344                 skb->tstamp = now;
 345                 smp_wmb();
 346                 sp->hdr.serial = serial;
 347                 if (whdr.flags & RXRPC_REQUEST_ACK) {
 348                         call->peer->rtt_last_req = now;
 349                         trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
 350                 }
 351         }
 352         _leave(" = %d [%u]", ret, call->peer->maxdata);
 353         return ret;
 354
 355 send_fragmentable:
 356         /* attempt to send this message with fragmentation enabled */
 357         _debug("send fragment");
 358
 359         down_write(&conn->params.local->defrag_sem);
 360
 361         switch (conn->params.local->srx.transport.family) {
 362         case AF_INET:
 363                 opt = IP_PMTUDISC_DONT;
 364                 ret = kernel_setsockopt(conn->params.local->socket,
 365                                         SOL_IP, IP_MTU_DISCOVER,
 366                                         (char *)&opt, sizeof(opt));
 367                 if (ret == 0) {
 368                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 369                                              iov, 2, len);
 370
 371                         opt = IP_PMTUDISC_DO;
 372                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 373                                           IP_MTU_DISCOVER,
 374                                           (char *)&opt, sizeof(opt));
 375                 }
 376                 break;
 377
 378 #ifdef CONFIG_AF_RXRPC_IPV6
 379         case AF_INET6:
 380                 opt = IPV6_PMTUDISC_DONT;
 381                 ret = kernel_setsockopt(conn->params.local->socket,
 382                                         SOL_IPV6, IPV6_MTU_DISCOVER,
 383                                         (char *)&opt, sizeof(opt));
 384                 if (ret == 0) {
 385                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 386                                              iov, 2, len);
 387
 388                         opt = IPV6_PMTUDISC_DO;
 389                         kernel_setsockopt(conn->params.local->socket,
 390                                           SOL_IPV6, IPV6_MTU_DISCOVER,
 391                                           (char *)&opt, sizeof(opt));
 392                 }
 393                 break;
 394 #endif
 395
 396         default:
 397                 BUG();
 398         }
 399
 400         up_write(&conn->params.local->defrag_sem);
 401         goto done;
 402 }
 403
 404 /*
 405  * reject packets through the local endpoint
 406  */
 407 void rxrpc_reject_packets(struct rxrpc_local *local)
 408 {
 409         struct sockaddr_rxrpc srx;
 410         struct rxrpc_skb_priv *sp;
 411         struct rxrpc_wire_header whdr;
 412         struct sk_buff *skb;
 413         struct msghdr msg;
 414         struct kvec iov[2];
 415         size_t size;
 416         __be32 code;
 417
 418         _enter("%d", local->debug_id);
 419
 420         iov[0].iov_base = &whdr;
 421         iov[0].iov_len = sizeof(whdr);
 422         iov[1].iov_base = &code;
 423         iov[1].iov_len = sizeof(code);
 424         size = sizeof(whdr) + sizeof(code);
 425
 426         msg.msg_name = &srx.transport;
 427         msg.msg_control = NULL;
 428         msg.msg_controllen = 0;
 429         msg.msg_flags = 0;
 430
 431         memset(&whdr, 0, sizeof(whdr));
 432         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 433
 434         while ((skb = skb_dequeue(&local->reject_queue))) {
 435                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 436                 sp = rxrpc_skb(skb);
 437
 438                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 439                         msg.msg_namelen = srx.transport_len;
 440
 441                         code = htonl(skb->priority);
 442
 443                         whdr.epoch      = htonl(sp->hdr.epoch);
 444                         whdr.cid        = htonl(sp->hdr.cid);
 445                         whdr.callNumber = htonl(sp->hdr.callNumber);
 446                         whdr.serviceId  = htons(sp->hdr.serviceId);
 447                         whdr.flags      = sp->hdr.flags;
 448                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 449                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 450
 451                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 452                 }
 453
 454                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 455         }
 456
 457         _leave("");
 458 }