contrib/bind-9.5.2/lib/dns/tcpmsg.c

   1 /*
   2  * Copyright (C) 2004-2007  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 1999-2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and/or 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 1.31 2007/06/19 23:47:16 tbox Exp $ */
  19
  20 /*! \file */
  21
  22 #include <config.h>
  23
  24 #include <isc/mem.h>
  25 #include <isc/task.h>
  26 #include <isc/util.h>
  27
  28 #include <dns/events.h>
  29 #include <dns/result.h>
  30 #include <dns/tcpmsg.h>
  31
  32 #ifdef TCPMSG_DEBUG
  33 #include <stdio.h>              /* Required for printf. */
  34 #define XDEBUG(x) printf x
  35 #else
  36 #define XDEBUG(x)
  37 #endif
  38
  39 #define TCPMSG_MAGIC            ISC_MAGIC('T', 'C', 'P', 'm')
  40 #define VALID_TCPMSG(foo)       ISC_MAGIC_VALID(foo, TCPMSG_MAGIC)
  41
  42 static void recv_length(isc_task_t *, isc_event_t *);
  43 static void recv_message(isc_task_t *, isc_event_t *);
  44
  45
  46 static void
  47 recv_length(isc_task_t *task, isc_event_t *ev_in) {
  48         isc_socketevent_t *ev = (isc_socketevent_t *)ev_in;
  49         isc_event_t *dev;
  50         dns_tcpmsg_t *tcpmsg = ev_in->ev_arg;
  51         isc_region_t region;
  52         isc_result_t result;
  53
  54         INSIST(VALID_TCPMSG(tcpmsg));
  55
  56         dev = &tcpmsg->event;
  57         tcpmsg->address = ev->address;
  58
  59         if (ev->result != ISC_R_SUCCESS) {
  60                 tcpmsg->result = ev->result;
  61                 goto send_and_free;
  62         }
  63
  64         /*
  65          * Success.
  66          */
  67         tcpmsg->size = ntohs(tcpmsg->size);
  68         if (tcpmsg->size == 0) {
  69                 tcpmsg->result = ISC_R_UNEXPECTEDEND;
  70                 goto send_and_free;
  71         }
  72         if (tcpmsg->size > tcpmsg->maxsize) {
  73                 tcpmsg->result = ISC_R_RANGE;
  74                 goto send_and_free;
  75         }
  76
  77         region.base = isc_mem_get(tcpmsg->mctx, tcpmsg->size);
  78         region.length = tcpmsg->size;
  79         if (region.base == NULL) {
  80                 tcpmsg->result = ISC_R_NOMEMORY;
  81                 goto send_and_free;
  82         }
  83         XDEBUG(("Allocated %d bytes\n", tcpmsg->size));
  84
  85         isc_buffer_init(&tcpmsg->buffer, region.base, region.length);
  86         result = isc_socket_recv(tcpmsg->sock, &region, 0,
  87                                  task, recv_message, tcpmsg);
  88         if (result != ISC_R_SUCCESS) {
  89                 tcpmsg->result = result;
  90                 goto send_and_free;
  91         }
  92
  93         isc_event_free(&ev_in);
  94         return;
  95
  96  send_and_free:
  97         isc_task_send(tcpmsg->task, &dev);
  98         tcpmsg->task = NULL;
  99         isc_event_free(&ev_in);
 100         return;
 101 }
 102
 103 static void
 104 recv_message(isc_task_t *task, isc_event_t *ev_in) {
 105         isc_socketevent_t *ev = (isc_socketevent_t *)ev_in;
 106         isc_event_t *dev;
 107         dns_tcpmsg_t *tcpmsg = ev_in->ev_arg;
 108
 109         (void)task;
 110
 111         INSIST(VALID_TCPMSG(tcpmsg));
 112
 113         dev = &tcpmsg->event;
 114         tcpmsg->address = ev->address;
 115
 116         if (ev->result != ISC_R_SUCCESS) {
 117                 tcpmsg->result = ev->result;
 118                 goto send_and_free;
 119         }
 120
 121         tcpmsg->result = ISC_R_SUCCESS;
 122         isc_buffer_add(&tcpmsg->buffer, ev->n);
 123
 124         XDEBUG(("Received %d bytes (of %d)\n", ev->n, tcpmsg->size));
 125
 126  send_and_free:
 127         isc_task_send(tcpmsg->task, &dev);
 128         tcpmsg->task = NULL;
 129         isc_event_free(&ev_in);
 130 }
 131
 132 void
 133 dns_tcpmsg_init(isc_mem_t *mctx, isc_socket_t *sock, dns_tcpmsg_t *tcpmsg) {
 134         REQUIRE(mctx != NULL);
 135         REQUIRE(sock != NULL);
 136         REQUIRE(tcpmsg != NULL);
 137
 138         tcpmsg->magic = TCPMSG_MAGIC;
 139         tcpmsg->size = 0;
 140         tcpmsg->buffer.base = NULL;
 141         tcpmsg->buffer.length = 0;
 142         tcpmsg->maxsize = 65535;                /* Largest message possible. */
 143         tcpmsg->mctx = mctx;
 144         tcpmsg->sock = sock;
 145         tcpmsg->task = NULL;                    /* None yet. */
 146         tcpmsg->result = ISC_R_UNEXPECTED;      /* None yet. */
 147         /*
 148          * Should probably initialize the event here, but it can wait.
 149          */
 150 }
 151
 152
 153 void
 154 dns_tcpmsg_setmaxsize(dns_tcpmsg_t *tcpmsg, unsigned int maxsize) {
 155         REQUIRE(VALID_TCPMSG(tcpmsg));
 156         REQUIRE(maxsize < 65536);
 157
 158         tcpmsg->maxsize = maxsize;
 159 }
 160
 161
 162 isc_result_t
 163 dns_tcpmsg_readmessage(dns_tcpmsg_t *tcpmsg,
 164                        isc_task_t *task, isc_taskaction_t action, void *arg)
 165 {
 166         isc_result_t result;
 167         isc_region_t region;
 168
 169         REQUIRE(VALID_TCPMSG(tcpmsg));
 170         REQUIRE(task != NULL);
 171         REQUIRE(tcpmsg->task == NULL);  /* not currently in use */
 172
 173         if (tcpmsg->buffer.base != NULL) {
 174                 isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base,
 175                             tcpmsg->buffer.length);
 176                 tcpmsg->buffer.base = NULL;
 177                 tcpmsg->buffer.length = 0;
 178         }
 179
 180         tcpmsg->task = task;
 181         tcpmsg->action = action;
 182         tcpmsg->arg = arg;
 183         tcpmsg->result = ISC_R_UNEXPECTED;  /* unknown right now */
 184
 185         ISC_EVENT_INIT(&tcpmsg->event, sizeof(isc_event_t), 0, 0,
 186                        DNS_EVENT_TCPMSG, action, arg, tcpmsg,
 187                        NULL, NULL);
 188
 189         region.base = (unsigned char *)&tcpmsg->size;
 190         region.length = 2;  /* isc_uint16_t */
 191         result = isc_socket_recv(tcpmsg->sock, &region, 0,
 192                                  tcpmsg->task, recv_length, tcpmsg);
 193
 194         if (result != ISC_R_SUCCESS)
 195                 tcpmsg->task = NULL;
 196
 197         return (result);
 198 }
 199
 200 void
 201 dns_tcpmsg_cancelread(dns_tcpmsg_t *tcpmsg) {
 202         REQUIRE(VALID_TCPMSG(tcpmsg));
 203
 204         isc_socket_cancel(tcpmsg->sock, NULL, ISC_SOCKCANCEL_RECV);
 205 }
 206
 207 void
 208 dns_tcpmsg_keepbuffer(dns_tcpmsg_t *tcpmsg, isc_buffer_t *buffer) {
 209         REQUIRE(VALID_TCPMSG(tcpmsg));
 210         REQUIRE(buffer != NULL);
 211
 212         *buffer = tcpmsg->buffer;
 213         tcpmsg->buffer.base = NULL;
 214         tcpmsg->buffer.length = 0;
 215 }
 216
 217 #if 0
 218 void
 219 dns_tcpmsg_freebuffer(dns_tcpmsg_t *tcpmsg) {
 220         REQUIRE(VALID_TCPMSG(tcpmsg));
 221
 222         if (tcpmsg->buffer.base == NULL)
 223                 return;
 224
 225         isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base, tcpmsg->buffer.length);
 226         tcpmsg->buffer.base = NULL;
 227         tcpmsg->buffer.length = 0;
 228 }
 229 #endif
 230
 231 void
 232 dns_tcpmsg_invalidate(dns_tcpmsg_t *tcpmsg) {
 233         REQUIRE(VALID_TCPMSG(tcpmsg));
 234
 235         tcpmsg->magic = 0;
 236
 237         if (tcpmsg->buffer.base != NULL) {
 238                 isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base,
 239                             tcpmsg->buffer.length);
 240                 tcpmsg->buffer.base = NULL;
 241                 tcpmsg->buffer.length = 0;
 242         }
 243 }