contrib/bind-9.3/lib/dns/tcpmsg.c

   1 /*
   2  * Copyright (C) 2004, 2006  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: tcpmsg.c,v 1.24.206.3 2006/08/10 23:59:28 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <isc/mem.h>
  23 #include <isc/task.h>
  24 #include <isc/util.h>
  25
  26 #include <dns/events.h>
  27 #include <dns/result.h>
  28 #include <dns/tcpmsg.h>
  29
  30 #ifdef TCPMSG_DEBUG
  31 #include <stdio.h>              /* Required for printf. */
  32 #define XDEBUG(x) printf x
  33 #else
  34 #define XDEBUG(x)
  35 #endif
  36
  37 #define TCPMSG_MAGIC            ISC_MAGIC('T', 'C', 'P', 'm')
  38 #define VALID_TCPMSG(foo)       ISC_MAGIC_VALID(foo, TCPMSG_MAGIC)
  39
  40 static void recv_length(isc_task_t *, isc_event_t *);
  41 static void recv_message(isc_task_t *, isc_event_t *);
  42
  43
  44 static void
  45 recv_length(isc_task_t *task, isc_event_t *ev_in) {
  46         isc_socketevent_t *ev = (isc_socketevent_t *)ev_in;
  47         isc_event_t *dev;
  48         dns_tcpmsg_t *tcpmsg = ev_in->ev_arg;
  49         isc_region_t region;
  50         isc_result_t result;
  51
  52         INSIST(VALID_TCPMSG(tcpmsg));
  53
  54         dev = &tcpmsg->event;
  55         tcpmsg->address = ev->address;
  56
  57         if (ev->result != ISC_R_SUCCESS) {
  58                 tcpmsg->result = ev->result;
  59                 goto send_and_free;
  60         }
  61
  62         /*
  63          * Success.
  64          */
  65         tcpmsg->size = ntohs(tcpmsg->size);
  66         if (tcpmsg->size == 0) {
  67                 tcpmsg->result = ISC_R_UNEXPECTEDEND;
  68                 goto send_and_free;
  69         }
  70         if (tcpmsg->size > tcpmsg->maxsize) {
  71                 tcpmsg->result = ISC_R_RANGE;
  72                 goto send_and_free;
  73         }
  74
  75         region.base = isc_mem_get(tcpmsg->mctx, tcpmsg->size);
  76         region.length = tcpmsg->size;
  77         if (region.base == NULL) {
  78                 tcpmsg->result = ISC_R_NOMEMORY;
  79                 goto send_and_free;
  80         }
  81         XDEBUG(("Allocated %d bytes\n", tcpmsg->size));
  82
  83         isc_buffer_init(&tcpmsg->buffer, region.base, region.length);
  84         result = isc_socket_recv(tcpmsg->sock, &region, 0,
  85                                  task, recv_message, tcpmsg);
  86         if (result != ISC_R_SUCCESS) {
  87                 tcpmsg->result = result;
  88                 goto send_and_free;
  89         }
  90
  91         isc_event_free(&ev_in);
  92         return;
  93
  94  send_and_free:
  95         isc_task_send(tcpmsg->task, &dev);
  96         tcpmsg->task = NULL;
  97         isc_event_free(&ev_in);
  98         return;
  99 }
 100
 101 static void
 102 recv_message(isc_task_t *task, isc_event_t *ev_in) {
 103         isc_socketevent_t *ev = (isc_socketevent_t *)ev_in;
 104         isc_event_t *dev;
 105         dns_tcpmsg_t *tcpmsg = ev_in->ev_arg;
 106
 107         (void)task;
 108
 109         INSIST(VALID_TCPMSG(tcpmsg));
 110
 111         dev = &tcpmsg->event;
 112         tcpmsg->address = ev->address;
 113
 114         if (ev->result != ISC_R_SUCCESS) {
 115                 tcpmsg->result = ev->result;
 116                 goto send_and_free;
 117         }
 118
 119         tcpmsg->result = ISC_R_SUCCESS;
 120         isc_buffer_add(&tcpmsg->buffer, ev->n);
 121
 122         XDEBUG(("Received %d bytes (of %d)\n", ev->n, tcpmsg->size));
 123
 124  send_and_free:
 125         isc_task_send(tcpmsg->task, &dev);
 126         tcpmsg->task = NULL;
 127         isc_event_free(&ev_in);
 128 }
 129
 130 void
 131 dns_tcpmsg_init(isc_mem_t *mctx, isc_socket_t *sock, dns_tcpmsg_t *tcpmsg) {
 132         REQUIRE(mctx != NULL);
 133         REQUIRE(sock != NULL);
 134         REQUIRE(tcpmsg != NULL);
 135
 136         tcpmsg->magic = TCPMSG_MAGIC;
 137         tcpmsg->size = 0;
 138         tcpmsg->buffer.base = NULL;
 139         tcpmsg->buffer.length = 0;
 140         tcpmsg->maxsize = 65535;                /* Largest message possible. */
 141         tcpmsg->mctx = mctx;
 142         tcpmsg->sock = sock;
 143         tcpmsg->task = NULL;                    /* None yet. */
 144         tcpmsg->result = ISC_R_UNEXPECTED;      /* None yet. */
 145         /*
 146          * Should probably initialize the event here, but it can wait.
 147          */
 148 }
 149
 150
 151 void
 152 dns_tcpmsg_setmaxsize(dns_tcpmsg_t *tcpmsg, unsigned int maxsize) {
 153         REQUIRE(VALID_TCPMSG(tcpmsg));
 154         REQUIRE(maxsize < 65536);
 155
 156         tcpmsg->maxsize = maxsize;
 157 }
 158
 159
 160 isc_result_t
 161 dns_tcpmsg_readmessage(dns_tcpmsg_t *tcpmsg,
 162                        isc_task_t *task, isc_taskaction_t action, void *arg)
 163 {
 164         isc_result_t result;
 165         isc_region_t region;
 166
 167         REQUIRE(VALID_TCPMSG(tcpmsg));
 168         REQUIRE(task != NULL);
 169         REQUIRE(tcpmsg->task == NULL);  /* not currently in use */
 170
 171         if (tcpmsg->buffer.base != NULL) {
 172                 isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base,
 173                             tcpmsg->buffer.length);
 174                 tcpmsg->buffer.base = NULL;
 175                 tcpmsg->buffer.length = 0;
 176         }
 177
 178         tcpmsg->task = task;
 179         tcpmsg->action = action;
 180         tcpmsg->arg = arg;
 181         tcpmsg->result = ISC_R_UNEXPECTED;  /* unknown right now */
 182
 183         ISC_EVENT_INIT(&tcpmsg->event, sizeof(isc_event_t), 0, 0,
 184                        DNS_EVENT_TCPMSG, action, arg, tcpmsg,
 185                        NULL, NULL);
 186
 187         region.base = (unsigned char *)&tcpmsg->size;
 188         region.length = 2;  /* isc_uint16_t */
 189         result = isc_socket_recv(tcpmsg->sock, &region, 0,
 190                                  tcpmsg->task, recv_length, tcpmsg);
 191
 192         if (result != ISC_R_SUCCESS)
 193                 tcpmsg->task = NULL;
 194
 195         return (result);
 196 }
 197
 198 void
 199 dns_tcpmsg_cancelread(dns_tcpmsg_t *tcpmsg) {
 200         REQUIRE(VALID_TCPMSG(tcpmsg));
 201
 202         isc_socket_cancel(tcpmsg->sock, NULL, ISC_SOCKCANCEL_RECV);
 203 }
 204
 205 void
 206 dns_tcpmsg_keepbuffer(dns_tcpmsg_t *tcpmsg, isc_buffer_t *buffer) {
 207         REQUIRE(VALID_TCPMSG(tcpmsg));
 208         REQUIRE(buffer != NULL);
 209
 210         *buffer = tcpmsg->buffer;
 211         tcpmsg->buffer.base = NULL;
 212         tcpmsg->buffer.length = 0;
 213 }
 214
 215 #if 0
 216 void
 217 dns_tcpmsg_freebuffer(dns_tcpmsg_t *tcpmsg) {
 218         REQUIRE(VALID_TCPMSG(tcpmsg));
 219
 220         if (tcpmsg->buffer.base == NULL)
 221                 return;
 222
 223         isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base, tcpmsg->buffer.length);
 224         tcpmsg->buffer.base = NULL;
 225         tcpmsg->buffer.length = 0;
 226 }
 227 #endif
 228
 229 void
 230 dns_tcpmsg_invalidate(dns_tcpmsg_t *tcpmsg) {
 231         REQUIRE(VALID_TCPMSG(tcpmsg));
 232
 233         tcpmsg->magic = 0;
 234
 235         if (tcpmsg->buffer.base != NULL) {
 236                 isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base,
 237                             tcpmsg->buffer.length);
 238                 tcpmsg->buffer.base = NULL;
 239                 tcpmsg->buffer.length = 0;
 240         }
 241 }