/*
 * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: lwresutil.c,v 1.2 2004/09/20 18:00:36 mcr Exp $ */

#include <config.h>

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <lwres/lwbuffer.h>
#include <lwres/lwres.h>
#include <lwres/result.h>

#include "assert_p.h"
#include "context_p.h"

/*
 * Requires:
 *
 *	The "current" pointer in "b" points to encoded raw data.
 *
 * Ensures:
 *
 *	The address of the first byte of the data is returned via "p",
 *	and the length is returned via "len".  If NULL, they are not
 *	set.
 *
 *	On return, the current pointer of "b" will point to the character
 *	following the data length and the data.
 *
 */
lwres_result_t
lwres_data_parse(lwres_buffer_t *b, unsigned char **p, lwres_uint16_t *len)
{
	lwres_uint16_t datalen;
	unsigned char *data;

	REQUIRE(b != NULL);

	/*
	 * Pull off the length (2 bytes)
	 */
	if (!SPACE_REMAINING(b, 2))
		return (LWRES_R_UNEXPECTEDEND);
	datalen = lwres_buffer_getuint16(b);

	/*
	 * Set the pointer to this string to the right place, then
	 * advance the buffer pointer.
	 */
	if (!SPACE_REMAINING(b, datalen))
		return (LWRES_R_UNEXPECTEDEND);
	data = b->base + b->current;
	lwres_buffer_forward(b, datalen);

	if (len != NULL)
		*len = datalen;
	if (p != NULL)
		*p = data;

	return (LWRES_R_SUCCESS);
}

/*
 * Requires:
 *
 *	The "current" pointer in "b" point to an encoded string.
 *
 * Ensures:
 *
 *	The address of the first byte of the string is returned via "c",
 *	and the length is returned via "len".  If NULL, they are not
 *	set.
 *
 *	On return, the current pointer of "b" will point to the character
 *	following the string length, the string, and the trailing NULL.
 *
 */
lwres_result_t
lwres_string_parse(lwres_buffer_t *b, char **c, lwres_uint16_t *len)
{
	lwres_uint16_t datalen;
	char *string;

	REQUIRE(b != NULL);

	/*
	 * Pull off the length (2 bytes)
	 */
	if (!SPACE_REMAINING(b, 2))
		return (LWRES_R_UNEXPECTEDEND);
	datalen = lwres_buffer_getuint16(b);

	/*
	 * Set the pointer to this string to the right place, then
	 * advance the buffer pointer.
	 */
	if (!SPACE_REMAINING(b, datalen))
		return (LWRES_R_UNEXPECTEDEND);
	string = (char *)b->base + b->current;
	lwres_buffer_forward(b, datalen);

	/*
	 * Skip the "must be zero" byte.
	 */
	if (!SPACE_REMAINING(b, 1))
		return (LWRES_R_UNEXPECTEDEND);
	if (0 != lwres_buffer_getuint8(b))
		return (LWRES_R_FAILURE);

	if (len != NULL)
		*len = datalen;
	if (c != NULL)
		*c = string;

	return (LWRES_R_SUCCESS);
}

lwres_result_t
lwres_addr_parse(lwres_buffer_t *b, lwres_addr_t *addr)
{
	REQUIRE(addr != NULL);

	if (!SPACE_REMAINING(b, 6))
		return (LWRES_R_UNEXPECTEDEND);

	addr->family = lwres_buffer_getuint32(b);
	addr->length = lwres_buffer_getuint16(b);

	if (!SPACE_REMAINING(b, addr->length))
		return (LWRES_R_UNEXPECTEDEND);
	if (addr->length > LWRES_ADDR_MAXLEN)
		return (LWRES_R_FAILURE);

	lwres_buffer_getmem(b, addr->address, addr->length);

	return (LWRES_R_SUCCESS);
}

lwres_result_t
lwres_getaddrsbyname(lwres_context_t *ctx, const char *name,
		     lwres_uint32_t addrtypes, lwres_gabnresponse_t **structp)
{
	lwres_gabnrequest_t request;
	lwres_gabnresponse_t *response;
	int ret;
	int recvlen;
	lwres_buffer_t b_in, b_out;
	lwres_lwpacket_t pkt;
	lwres_uint32_t serial;
	char *buffer;
	char target_name[1024];
	unsigned int target_length;

	REQUIRE(ctx != NULL);
	REQUIRE(name != NULL);
	REQUIRE(addrtypes != 0);
	REQUIRE(structp != NULL && *structp == NULL);

	b_in.base = NULL;
	b_out.base = NULL;
	response = NULL;
	buffer = NULL;
	serial = lwres_context_nextserial(ctx);

	buffer = CTXMALLOC(LWRES_RECVLENGTH);
	if (buffer == NULL) {
		ret = LWRES_R_NOMEMORY;
		goto out;
	}

	target_length = strlen(name);
	if (target_length >= sizeof(target_name))
		return (LWRES_R_FAILURE);
	strcpy(target_name, name); /* strcpy is safe */

	/*
	 * Set up our request and render it to a buffer.
	 */
	request.flags = 0;
	request.addrtypes = addrtypes;
	request.name = target_name;
	request.namelen = target_length;
	pkt.pktflags = 0;
	pkt.serial = serial;
	pkt.result = 0;
	pkt.recvlength = LWRES_RECVLENGTH;

 again:
	ret = lwres_gabnrequest_render(ctx, &request, &pkt, &b_out);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	ret = lwres_context_sendrecv(ctx, b_out.base, b_out.length, buffer,
				     LWRES_RECVLENGTH, &recvlen);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	lwres_buffer_init(&b_in, buffer, recvlen);
	b_in.used = recvlen;

	/*
	 * Parse the packet header.
	 */
	ret = lwres_lwpacket_parseheader(&b_in, &pkt);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	/*
	 * Sanity check.
	 */
	if (pkt.serial != serial)
		goto again;
	if (pkt.opcode != LWRES_OPCODE_GETADDRSBYNAME)
		goto again;

	/*
	 * Free what we've transmitted
	 */
	CTXFREE(b_out.base, b_out.length);
	b_out.base = NULL;
	b_out.length = 0;

	if (pkt.result != LWRES_R_SUCCESS) {
		ret = pkt.result;
		goto out;
	}

	/*
	 * Parse the response.
	 */
	ret = lwres_gabnresponse_parse(ctx, &b_in, &pkt, &response);
	if (ret != LWRES_R_SUCCESS)
		goto out;
	response->base = buffer;
	response->baselen = LWRES_RECVLENGTH;
	buffer = NULL; /* don't free this below */

	*structp = response;
	return (LWRES_R_SUCCESS);

 out:
	if (b_out.base != NULL)
		CTXFREE(b_out.base, b_out.length);
	if (buffer != NULL)
		CTXFREE(buffer, LWRES_RECVLENGTH);
	if (response != NULL)
		lwres_gabnresponse_free(ctx, &response);

	return (ret);
}


lwres_result_t
lwres_getnamebyaddr(lwres_context_t *ctx, lwres_uint32_t addrtype,
		    lwres_uint16_t addrlen, const unsigned char *addr,
		    lwres_gnbaresponse_t **structp)
{
	lwres_gnbarequest_t request;
	lwres_gnbaresponse_t *response;
	int ret;
	int recvlen;
	lwres_buffer_t b_in, b_out;
	lwres_lwpacket_t pkt;
	lwres_uint32_t serial;
	char *buffer;

	REQUIRE(ctx != NULL);
	REQUIRE(addrtype != 0);
	REQUIRE(addrlen != 0);
	REQUIRE(addr != NULL);
	REQUIRE(structp != NULL && *structp == NULL);

	b_in.base = NULL;
	b_out.base = NULL;
	response = NULL;
	buffer = NULL;
	serial = lwres_context_nextserial(ctx);

	buffer = CTXMALLOC(LWRES_RECVLENGTH);
	if (buffer == NULL) {
		ret = LWRES_R_NOMEMORY;
		goto out;
	}

	/*
	 * Set up our request and render it to a buffer.
	 */
	request.flags = 0;
	request.addr.family = addrtype;
	request.addr.length = addrlen;
	memcpy(request.addr.address, addr, addrlen);
	pkt.pktflags = 0;
	pkt.serial = serial;
	pkt.result = 0;
	pkt.recvlength = LWRES_RECVLENGTH;

 again:
	ret = lwres_gnbarequest_render(ctx, &request, &pkt, &b_out);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	ret = lwres_context_sendrecv(ctx, b_out.base, b_out.length, buffer,
				     LWRES_RECVLENGTH, &recvlen);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	lwres_buffer_init(&b_in, buffer, recvlen);
	b_in.used = recvlen;

	/*
	 * Parse the packet header.
	 */
	ret = lwres_lwpacket_parseheader(&b_in, &pkt);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	/*
	 * Sanity check.
	 */
	if (pkt.serial != serial)
		goto again;
	if (pkt.opcode != LWRES_OPCODE_GETNAMEBYADDR)
		goto again;

	/*
	 * Free what we've transmitted
	 */
	CTXFREE(b_out.base, b_out.length);
	b_out.base = NULL;
	b_out.length = 0;

	if (pkt.result != LWRES_R_SUCCESS) {
		ret = pkt.result;
		goto out;
	}

	/*
	 * Parse the response.
	 */
	ret = lwres_gnbaresponse_parse(ctx, &b_in, &pkt, &response);
	if (ret != LWRES_R_SUCCESS)
		goto out;
	response->base = buffer;
	response->baselen = LWRES_RECVLENGTH;
	buffer = NULL; /* don't free this below */

	*structp = response;
	return (LWRES_R_SUCCESS);

 out:
	if (b_out.base != NULL)
		CTXFREE(b_out.base, b_out.length);
	if (buffer != NULL)
		CTXFREE(buffer, LWRES_RECVLENGTH);
	if (response != NULL)
		lwres_gnbaresponse_free(ctx, &response);

	return (ret);
}

lwres_result_t
lwres_getrdatabyname(lwres_context_t *ctx, const char *name,
		     lwres_uint16_t rdclass, lwres_uint16_t rdtype,
		     lwres_uint32_t flags, lwres_grbnresponse_t **structp)
{
	int ret;
	int recvlen;
	lwres_buffer_t b_in, b_out;
	lwres_lwpacket_t pkt;
	lwres_uint32_t serial;
	char *buffer;
	lwres_grbnrequest_t request;
	lwres_grbnresponse_t *response;
	char target_name[1024];
	unsigned int target_length;

	REQUIRE(ctx != NULL);
	REQUIRE(name != NULL);
	REQUIRE(structp != NULL && *structp == NULL);

	b_in.base = NULL;
	b_out.base = NULL;
	response = NULL;
	buffer = NULL;
	serial = lwres_context_nextserial(ctx);

	buffer = CTXMALLOC(LWRES_RECVLENGTH);
	if (buffer == NULL) {
		ret = LWRES_R_NOMEMORY;
		goto out;
	}

	target_length = strlen(name);
	if (target_length >= sizeof(target_name))
		return (LWRES_R_FAILURE);
	strcpy(target_name, name); /* strcpy is safe */

	/*
	 * Set up our request and render it to a buffer.
	 */
	request.rdclass = rdclass;
	request.rdtype = rdtype;
	request.flags = flags;
	request.name = target_name;
	request.namelen = target_length;
	pkt.pktflags = 0;
	pkt.serial = serial;
	pkt.result = 0;
	pkt.recvlength = LWRES_RECVLENGTH;

 again:
	ret = lwres_grbnrequest_render(ctx, &request, &pkt, &b_out);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	ret = lwres_context_sendrecv(ctx, b_out.base, b_out.length, buffer,
				     LWRES_RECVLENGTH, &recvlen);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	lwres_buffer_init(&b_in, buffer, recvlen);
	b_in.used = recvlen;

	/*
	 * Parse the packet header.
	 */
	ret = lwres_lwpacket_parseheader(&b_in, &pkt);
	if (ret != LWRES_R_SUCCESS)
		goto out;

	/*
	 * Sanity check.
	 */
	if (pkt.serial != serial)
		goto again;
	if (pkt.opcode != LWRES_OPCODE_GETRDATABYNAME)
		goto again;

	/*
	 * Free what we've transmitted
	 */
	CTXFREE(b_out.base, b_out.length);
	b_out.base = NULL;
	b_out.length = 0;

	if (pkt.result != LWRES_R_SUCCESS) {
		ret = pkt.result;
		goto out;
	}

	/*
	 * Parse the response.
	 */
	ret = lwres_grbnresponse_parse(ctx, &b_in, &pkt, &response);
	if (ret != LWRES_R_SUCCESS)
		goto out;
	response->base = buffer;
	response->baselen = LWRES_RECVLENGTH;
	buffer = NULL; /* don't free this below */

	*structp = response;
	return (LWRES_R_SUCCESS);

 out:
	if (b_out.base != NULL)
		CTXFREE(b_out.base, b_out.length);
	if (buffer != NULL)
		CTXFREE(buffer, LWRES_RECVLENGTH);
	if (response != NULL)
		lwres_grbnresponse_free(ctx, &response);

	return (ret);
}