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_seq_t hard_ack, top, seq;
  42         int ix;
  43         u32 mtu, jmax;
  44         u8 *ackp = pkt->acks;
  45
  46         /* Barrier against rxrpc_input_data(). */
  47         hard_ack = READ_ONCE(call->rx_hard_ack);
  48         top = smp_load_acquire(&call->rx_top);
  49
  50         pkt->ack.bufferSpace    = htons(8);
  51         pkt->ack.maxSkew        = htons(call->ackr_skew);
  52         pkt->ack.firstPacket    = htonl(hard_ack + 1);
  53         pkt->ack.previousPacket = htonl(call->ackr_prev_seq);
  54         pkt->ack.serial         = htonl(call->ackr_serial);
  55         pkt->ack.reason         = call->ackr_reason;
  56         pkt->ack.nAcks          = top - hard_ack;
  57
  58         if (after(top, hard_ack)) {
  59                 seq = hard_ack + 1;
  60                 do {
  61                         ix = seq & RXRPC_RXTX_BUFF_MASK;
  62                         if (call->rxtx_buffer[ix])
  63                                 *ackp++ = RXRPC_ACK_TYPE_ACK;
  64                         else
  65                                 *ackp++ = RXRPC_ACK_TYPE_NACK;
  66                         seq++;
  67                 } while (before_eq(seq, top));
  68         }
  69
  70         mtu = call->conn->params.peer->if_mtu;
  71         mtu -= call->conn->params.peer->hdrsize;
  72         jmax = (call->nr_jumbo_bad > 3) ? 1 : rxrpc_rx_jumbo_max;
  73         pkt->ackinfo.rxMTU      = htonl(rxrpc_rx_mtu);
  74         pkt->ackinfo.maxMTU     = htonl(mtu);
  75         pkt->ackinfo.rwind      = htonl(call->rx_winsize);
  76         pkt->ackinfo.jumbo_max  = htonl(jmax);
  77
  78         *ackp++ = 0;
  79         *ackp++ = 0;
  80         *ackp++ = 0;
  81         return top - hard_ack + 3;
  82 }
  83
  84 /*
  85  * Send an ACK or ABORT call packet.
  86  */
  87 int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
  88 {
  89         struct rxrpc_connection *conn = NULL;
  90         struct rxrpc_pkt_buffer *pkt;
  91         struct msghdr msg;
  92         struct kvec iov[2];
  93         rxrpc_serial_t serial;
  94         size_t len, n;
  95         int ioc, ret;
  96         u32 abort_code;
  97
  98         _enter("%u,%s", call->debug_id, rxrpc_pkts[type]);
  99
 100         spin_lock_bh(&call->lock);
 101         if (call->conn)
 102                 conn = rxrpc_get_connection_maybe(call->conn);
 103         spin_unlock_bh(&call->lock);
 104         if (!conn)
 105                 return -ECONNRESET;
 106
 107         pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
 108         if (!pkt) {
 109                 rxrpc_put_connection(conn);
 110                 return -ENOMEM;
 111         }
 112
 113         serial = atomic_inc_return(&conn->serial);
 114
 115         msg.msg_name    = &call->peer->srx.transport;
 116         msg.msg_namelen = call->peer->srx.transport_len;
 117         msg.msg_control = NULL;
 118         msg.msg_controllen = 0;
 119         msg.msg_flags   = 0;
 120
 121         pkt->whdr.epoch         = htonl(conn->proto.epoch);
 122         pkt->whdr.cid           = htonl(call->cid);
 123         pkt->whdr.callNumber    = htonl(call->call_id);
 124         pkt->whdr.seq           = 0;
 125         pkt->whdr.serial        = htonl(serial);
 126         pkt->whdr.type          = type;
 127         pkt->whdr.flags         = conn->out_clientflag;
 128         pkt->whdr.userStatus    = 0;
 129         pkt->whdr.securityIndex = call->security_ix;
 130         pkt->whdr._rsvd         = 0;
 131         pkt->whdr.serviceId     = htons(call->service_id);
 132
 133         iov[0].iov_base = pkt;
 134         iov[0].iov_len  = sizeof(pkt->whdr);
 135         len = sizeof(pkt->whdr);
 136
 137         switch (type) {
 138         case RXRPC_PACKET_TYPE_ACK:
 139                 spin_lock_bh(&call->lock);
 140                 n = rxrpc_fill_out_ack(call, pkt);
 141                 call->ackr_reason = 0;
 142
 143                 spin_unlock_bh(&call->lock);
 144
 145                 _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 146                        serial,
 147                        ntohs(pkt->ack.maxSkew),
 148                        ntohl(pkt->ack.firstPacket),
 149                        ntohl(pkt->ack.previousPacket),
 150                        ntohl(pkt->ack.serial),
 151                        rxrpc_acks(pkt->ack.reason),
 152                        pkt->ack.nAcks);
 153
 154                 iov[0].iov_len += sizeof(pkt->ack) + n;
 155                 iov[1].iov_base = &pkt->ackinfo;
 156                 iov[1].iov_len  = sizeof(pkt->ackinfo);
 157                 len += sizeof(pkt->ack) + n + sizeof(pkt->ackinfo);
 158                 ioc = 2;
 159                 break;
 160
 161         case RXRPC_PACKET_TYPE_ABORT:
 162                 abort_code = call->abort_code;
 163                 pkt->abort_code = htonl(abort_code);
 164                 _proto("Tx ABORT %%%u { %d }", serial, abort_code);
 165                 iov[0].iov_len += sizeof(pkt->abort_code);
 166                 len += sizeof(pkt->abort_code);
 167                 ioc = 1;
 168                 break;
 169
 170         default:
 171                 BUG();
 172                 ret = -ENOANO;
 173                 goto out;
 174         }
 175
 176         ret = kernel_sendmsg(conn->params.local->socket,
 177                              &msg, iov, ioc, len);
 178
 179         if (ret < 0 && call->state < RXRPC_CALL_COMPLETE) {
 180                 switch (pkt->whdr.type) {
 181                 case RXRPC_PACKET_TYPE_ACK:
 182                         rxrpc_propose_ACK(call, pkt->ack.reason,
 183                                           ntohs(pkt->ack.maxSkew),
 184                                           ntohl(pkt->ack.serial),
 185                                           true, true);
 186                         break;
 187                 case RXRPC_PACKET_TYPE_ABORT:
 188                         break;
 189                 }
 190         }
 191
 192 out:
 193         rxrpc_put_connection(conn);
 194         kfree(pkt);
 195         return ret;
 196 }
 197
 198 /*
 199  * send a packet through the transport endpoint
 200  */
 201 int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
 202 {
 203         struct kvec iov[1];
 204         struct msghdr msg;
 205         int ret, opt;
 206
 207         _enter(",{%d}", skb->len);
 208
 209         iov[0].iov_base = skb->head;
 210         iov[0].iov_len = skb->len;
 211
 212         msg.msg_name = &conn->params.peer->srx.transport;
 213         msg.msg_namelen = conn->params.peer->srx.transport_len;
 214         msg.msg_control = NULL;
 215         msg.msg_controllen = 0;
 216         msg.msg_flags = 0;
 217
 218         /* send the packet with the don't fragment bit set if we currently
 219          * think it's small enough */
 220         if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
 221                 down_read(&conn->params.local->defrag_sem);
 222                 /* send the packet by UDP
 223                  * - returns -EMSGSIZE if UDP would have to fragment the packet
 224                  *   to go out of the interface
 225                  *   - in which case, we'll have processed the ICMP error
 226                  *     message and update the peer record
 227                  */
 228                 ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 229                                      iov[0].iov_len);
 230
 231                 up_read(&conn->params.local->defrag_sem);
 232                 if (ret == -EMSGSIZE)
 233                         goto send_fragmentable;
 234
 235                 _leave(" = %d [%u]", ret, conn->params.peer->maxdata);
 236                 return ret;
 237         }
 238
 239 send_fragmentable:
 240         /* attempt to send this message with fragmentation enabled */
 241         _debug("send fragment");
 242
 243         down_write(&conn->params.local->defrag_sem);
 244
 245         switch (conn->params.local->srx.transport.family) {
 246         case AF_INET:
 247                 opt = IP_PMTUDISC_DONT;
 248                 ret = kernel_setsockopt(conn->params.local->socket,
 249                                         SOL_IP, IP_MTU_DISCOVER,
 250                                         (char *)&opt, sizeof(opt));
 251                 if (ret == 0) {
 252                         ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
 253                                              iov[0].iov_len);
 254
 255                         opt = IP_PMTUDISC_DO;
 256                         kernel_setsockopt(conn->params.local->socket, SOL_IP,
 257                                           IP_MTU_DISCOVER,
 258                                           (char *)&opt, sizeof(opt));
 259                 }
 260                 break;
 261         }
 262
 263         up_write(&conn->params.local->defrag_sem);
 264         _leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
 265         return ret;
 266 }
 267
 268 /*
 269  * reject packets through the local endpoint
 270  */
 271 void rxrpc_reject_packets(struct rxrpc_local *local)
 272 {
 273         struct sockaddr_rxrpc srx;
 274         struct rxrpc_skb_priv *sp;
 275         struct rxrpc_wire_header whdr;
 276         struct sk_buff *skb;
 277         struct msghdr msg;
 278         struct kvec iov[2];
 279         size_t size;
 280         __be32 code;
 281
 282         _enter("%d", local->debug_id);
 283
 284         iov[0].iov_base = &whdr;
 285         iov[0].iov_len = sizeof(whdr);
 286         iov[1].iov_base = &code;
 287         iov[1].iov_len = sizeof(code);
 288         size = sizeof(whdr) + sizeof(code);
 289
 290         msg.msg_name = &srx.transport;
 291         msg.msg_control = NULL;
 292         msg.msg_controllen = 0;
 293         msg.msg_flags = 0;
 294
 295         memset(&whdr, 0, sizeof(whdr));
 296         whdr.type = RXRPC_PACKET_TYPE_ABORT;
 297
 298         while ((skb = skb_dequeue(&local->reject_queue))) {
 299                 rxrpc_see_skb(skb);
 300                 sp = rxrpc_skb(skb);
 301
 302                 if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
 303                         msg.msg_namelen = srx.transport_len;
 304
 305                         code = htonl(skb->priority);
 306
 307                         whdr.epoch      = htonl(sp->hdr.epoch);
 308                         whdr.cid        = htonl(sp->hdr.cid);
 309                         whdr.callNumber = htonl(sp->hdr.callNumber);
 310                         whdr.serviceId  = htons(sp->hdr.serviceId);
 311                         whdr.flags      = sp->hdr.flags;
 312                         whdr.flags      ^= RXRPC_CLIENT_INITIATED;
 313                         whdr.flags      &= RXRPC_CLIENT_INITIATED;
 314
 315                         kernel_sendmsg(local->socket, &msg, iov, 2, size);
 316                 }
 317
 318                 rxrpc_free_skb(skb);
 319         }
 320
 321         _leave("");
 322 }