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