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