/contrib/bind9/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
 42static void recv_length(isc_task_t *, isc_event_t *);
 43static void recv_message(isc_task_t *, isc_event_t *);
 44
 45
 46static void
 47recv_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
103static void
104recv_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
132void
133dns_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
153void
154dns_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
162isc_result_t
163dns_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
200void
201dns_tcpmsg_cancelread(dns_tcpmsg_t *tcpmsg) {
202	REQUIRE(VALID_TCPMSG(tcpmsg));
203
204	isc_socket_cancel(tcpmsg->sock, NULL, ISC_SOCKCANCEL_RECV);
205}
206
207void
208dns_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
218void
219dns_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
231void
232dns_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}