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 (after(top, hard_ack)) {
  61                 seq = hard_ack + 1;
  62                 do {
  63                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  64                         if (call->rxtx_buffer[ix])
  65                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  66                         else
  67                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  68                         seq++;
  69                 } while (before_eq(seq, top));
  70         }
  71
  72         mtu = call->conn->params.peer->if_mtu;
  73         mtu -= call->conn->params.peer->hdrsize;
  74         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
  75         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
  76         pkt->ackinfo.maxMTU     = htonl(mtu);
  77         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
  78         pkt->ackinfo.jumbo_max  = htonl(jmax);
  79
  80         trace_rxrpc_tx_ack(call, hard_ack + 1, serial, call->ackr_reason,
  81                            top - hard_ack);
  82
  83         *ackp++ = 0;
  84         *ackp++ = 0;
  85         *ackp++ = 0;
  86         return top - hard_ack + 3;
  87 }
  88
  89 /*
  90  * Send an ACK or ABORT call packet.
  91  */
  92 int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
  93 {
  94         struct rxrpc_connection *conn = NULL;
  95         struct rxrpc_pkt_buffer *pkt;
  96         struct msghdr msg;
  97         struct kvec iov[2];
  98         rxrpc_serial_t serial;
  99         size_t len, n;
 100         int ioc, ret;
 101         u32 abort_code;
 102
 103         _enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
 104
 105         spin_lock_bh(&call->lock);
 106         if (call->conn)
 107                 conn = rxrpc_get_connection_maybe(call->conn);
 108         spin_unlock_bh(&call->lock);
 109         if (!conn)
 110                 return -ECONNRESET;
 111
 112         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 113         if (!pkt) {
 114                 rxrpc_put_connection(conn);
 115                 return -ENOMEM;
 116         }
 117
 118         serial = atomic_inc_return(&conn->serial);
 119
 120         msg.msg_name    = &call->peer->srx.transport;
 121         msg.msg_namelen = call->peer->srx.transport_len;
 122         msg.msg_control = NULL;
 123         msg.msg_controllen = 0;
 124         msg.msg_flags   = 0;
 125
 126         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 127         pkt->whdr.cid           = htonl(call->cid);
 128         pkt->whdr.callNumber    = htonl(call->call_id);
 129         pkt->whdr.seq           = 0;
 130         pkt->whdr.serial        = htonl(serial);
 131         pkt->whdr.type          = type;
 132         pkt->whdr.flags         = conn->out_clientflag;
 133         pkt->whdr.userStatus    = 0;
 134         pkt->whdr.securityIndex = call->security_ix;
 135         pkt->whdr._rsvd         = 0;
 136         pkt->whdr.serviceId     = htons(call->service_id);
 137
 138         iov[0].iov_base = pkt;
 139         iov[0].iov_len  = sizeof(pkt->whdr);
 140         len = sizeof(pkt->whdr);
 141
 142         switch (type) {
 143         case RXRPC_PACKET_TYPE_ACK:
 144                 spin_lock_bh(&call->lock);
 145                 if (!call->ackr_reason) {
 146                         spin_unlock_bh(&call->lock);
 147                         ret = 0;
 148                         goto out;
 149                 }
 150                 n = rxrpc_fill_out_ack(call, pkt);
 151                 call->ackr_reason = 0;
 152
 153                 spin_unlock_bh(&call->lock);
 154
 155                 _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 156                        serial,
 157                        ntohs(pkt->ack.maxSkew),
 158                        ntohl(pkt->ack.firstPacket),
 159                        ntohl(pkt->ack.previousPacket),
 160                        ntohl(pkt->ack.serial),
 161                        rxrpc_acks(pkt->ack.reason),
 162                        pkt->ack.nAcks);
 163
 164                 iov[0].iov_len += sizeof(pkt->ack) + n;
 165                 iov[1].iov_base = &pkt->ackinfo;
 166                 iov[1].iov_len  = sizeof(pkt->ackinfo);
 167                 len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
 168                 ioc = 2;
 169                 break;
 170
 171         case RXRPC_PACKET_TYPE_ABORT:
 172                 abort_code = call->abort_code;
 173                 pkt->abort_code = htonl(abort_code);
 174                 _proto("Tx ABORT %%%u { %d }", serial, abort_code);
 175                 iov[0].iov_len += sizeof(pkt->abort_code);
 176                 len += sizeof(pkt->abort_code);
 177                 ioc = 1;
 178                 break;
 179
 180         default:
 181                 BUG();
 182                 ret = -ENOANO;
 183                 goto out;
 184         }
 185
 186         ret = kernel_sendmsg(conn->params.local->socket,
 187                              &msg, iov, ioc, len);
 188
 189         if (ret < 0 && call->state < RXRPC_CALL_COMPLETE) {
 190                 switch (type) {
 191                 case RXRPC_PACKET_TYPE_ACK:
 192                         rxrpc_propose_ACK(call, pkt->ack.reason,
 193                                           ntohs(pkt->ack.maxSkew),
 194                                           ntohl(pkt->ack.serial),
 195                                           true, true);
 196                         break;
 197                 case RXRPC_PACKET_TYPE_ABORT:
 198                         break;
 199                 }
 200         }
 201
 202 out:
 203         rxrpc_put_connection(conn);
 204         kfree(pkt);
 205         return ret;
 206 }
 207
 208 /*
 209  * send a packet through the transport endpoint
 210  */
 211 int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
 212 {
 213         struct kvec iov[1];
 214         struct msghdr msg;
 215         int ret, opt;
 216
 217         _enter(",{%d}", skb->len);
 218
 219         iov[0].iov_base = skb->head;
 220         iov[0].iov_len = skb->len;
 221
 222         msg.msg_name = &conn->params.peer->srx.transport;
 223         msg.msg_namelen = conn->params.peer->srx.transport_len;
 224         msg.msg_control = NULL;
 225         msg.msg_controllen = 0;
 226         msg.msg_flags = 0;
 227
 228         if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
 229                 static int lose;
 230                 if ((lose++ & 7) == 7) {
 231                         rxrpc_lose_skb(skb, rxrpc_skb_tx_lost);
 232                         _leave(" = 0 [lose]");
 233                         return 0;
 234                 }
 235         }
 236
 237         /* send the packet with the don't fragment bit set if we currently
 238          * think it's small enough */
 239         if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
 240                 down_read(&conn->params.local->defrag_sem);
 241                 /* send the packet by UDP
 242                  * - returns -EMSGSIZE if UDP would have to fragment the packet
 243                  *   to go out of the interface
 244                  *   - in which case, we'll have processed the ICMP error
 245                  *     message and update the peer record
 246                  */
 247                 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 248                                      iov[0].iov_len);
 249
 250                 up_read(&conn->params.local->defrag_sem);
 251                 if (ret == -EMSGSIZE)
 252                         goto send_fragmentable;
 253
 254                 _leave(" = %d [%u]", ret, conn->params.peer->maxdata);
 255                 return ret;
 256         }
 257
 258 send_fragmentable:
 259         /* attempt to send this message with fragmentation enabled */
 260         _debug("send fragment");
 261
 262         down_write(&conn->params.local->defrag_sem);
 263
 264         switch (conn->params.local->srx.transport.family) {
 265         case AF_INET:
 266                 opt = IP_PMTUDISC_DONT;
 267                 ret = kernel_setsockopt(conn->params.local->socket,
 268                                         SOL_IP, IP_MTU_DISCOVER,
 269                                         (char *)&opt, sizeof(opt));
 270                 if (ret == 0) {
 271                         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 272                                              iov[0].iov_len);
 273
 274                         opt = IP_PMTUDISC_DO;
 275                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 276                                           IP_MTU_DISCOVER,
 277                                           (char *)&opt, sizeof(opt));
 278                 }
 279                 break;
 280
 281 #ifdef CONFIG_AF_RXRPC_IPV6
 282         case AF_INET6:
 283                 opt = IPV6_PMTUDISC_DONT;
 284                 ret = kernel_setsockopt(conn->params.local->socket,
 285                                         SOL_IPV6, IPV6_MTU_DISCOVER,
 286                                         (char *)&opt, sizeof(opt));
 287                 if (ret == 0) {
 288                         ret = kernel_sendmsg(conn->params.local->socket, &msg,
 289                                              iov, 1, iov[0].iov_len);
 290
 291                         opt = IPV6_PMTUDISC_DO;
 292                         kernel_setsockopt(conn->params.local->socket,
 293                                           SOL_IPV6, IPV6_MTU_DISCOVER,
 294                                           (char *)&opt, sizeof(opt));
 295                 }
 296                 break;
 297 #endif
 298         }
 299
 300         up_write(&conn->params.local->defrag_sem);
 301         _leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
 302         return ret;
 303 }
 304
 305 /*
 306  * reject packets through the local endpoint
 307  */
 308 void rxrpc_reject_packets(struct rxrpc_local *local)
 309 {
 310         struct sockaddr_rxrpc srx;
 311         struct rxrpc_skb_priv *sp;
 312         struct rxrpc_wire_header whdr;
 313         struct sk_buff *skb;
 314         struct msghdr msg;
 315         struct kvec iov[2];
 316         size_t size;
 317         __be32 code;
 318
 319         _enter("%d", local->debug_id);
 320
 321         iov[0].iov_base = &whdr;
 322         iov[0].iov_len = sizeof(whdr);
 323         iov[1].iov_base = &code;
 324         iov[1].iov_len = sizeof(code);
 325         size = sizeof(whdr) + sizeof(code);
 326
 327         msg.msg_name = &srx.transport;
 328         msg.msg_control = NULL;
 329         msg.msg_controllen = 0;
 330         msg.msg_flags = 0;
 331
 332         memset(&whdr, 0, sizeof(whdr));
 333         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 334
 335         while ((skb = skb_dequeue(&local->reject_queue))) {
 336                 rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
 337                 sp = rxrpc_skb(skb);
 338
 339                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 340                         msg.msg_namelen = srx.transport_len;
 341
 342                         code = htonl(skb->priority);
 343
 344                         whdr.epoch      = htonl(sp->hdr.epoch);
 345                         whdr.cid        = htonl(sp->hdr.cid);
 346                         whdr.callNumber = htonl(sp->hdr.callNumber);
 347                         whdr.serviceId  = htons(sp->hdr.serviceId);
 348                         whdr.flags      = sp->hdr.flags;
 349                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 350                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 351
 352                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 353                 }
 354
 355                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 356         }
 357
 358         _leave("");
 359 }