host2wire.c

/*
 * host2wire.c
 *
 * conversion routines from the host to the wire format.
 * This will usually just a re-ordering of the
 * data (as we store it in network format)
 *
 * a Net::DNS like library for C
 *
 * (c) NLnet Labs, 2004-2006
 *
 * See the file LICENSE for the license
 */

#include <ldns/config.h>

#include <ldns/ldns.h>

ldns_status
ldns_dname2buffer_wire(ldns_buffer *buffer, const ldns_rdf *name)
{
	return ldns_dname2buffer_wire_compress(buffer, name, NULL);
}

ldns_status
ldns_dname2buffer_wire_compress(ldns_buffer *buffer, const ldns_rdf *name, ldns_rbtree_t *compression_data)
{
	ldns_rbnode_t *node;
	uint8_t *data;
	size_t size;
	ldns_rdf *label;
	ldns_rdf *rest;
	ldns_status s;

	/* If no tree, just add the data */
	if(!compression_data)
	{
		if (ldns_buffer_reserve(buffer, ldns_rdf_size(name)))
		{
			ldns_buffer_write(buffer, ldns_rdf_data(name), ldns_rdf_size(name));
		}
		return ldns_buffer_status(buffer);
	}

	/* No labels left, write final zero */
	if(ldns_dname_label_count(name)==0)
	{
		if(ldns_buffer_reserve(buffer,1))
		{
			ldns_buffer_write_u8(buffer, 0);
		}
		return ldns_buffer_status(buffer);
	}

	/* Can we find the name in the tree? */
	if((node = ldns_rbtree_search(compression_data, name)) != NULL)
	{
		/* Found */
		uint16_t position = (uint16_t) (intptr_t) node->data | 0xC000;
		if (ldns_buffer_reserve(buffer, 2))
		{
			ldns_buffer_write_u16(buffer, position);
		}
		return ldns_buffer_status(buffer);
	}
	else
	{
		/* Not found. Write cache entry, take off first label, write it, */
		/* try again with the rest of the name. */
		if (ldns_buffer_position(buffer) < 16384) {
			ldns_rdf *key;

			node = LDNS_MALLOC(ldns_rbnode_t);
			if(!node)
			{
				return LDNS_STATUS_MEM_ERR;
			}

			key = ldns_rdf_clone(name);
			if (!key) {
				LDNS_FREE(node);
				return LDNS_STATUS_MEM_ERR;
			}
			node->key = key;
			node->data = (void *) (intptr_t) ldns_buffer_position(buffer);
			if(!ldns_rbtree_insert(compression_data,node))
			{
				/* fprintf(stderr,"Name not found but now it's there?\n"); */
				ldns_rdf_deep_free(key);
				LDNS_FREE(node);
			}
		}
		label = ldns_dname_label(name, 0);
		rest = ldns_dname_left_chop(name);
		size = ldns_rdf_size(label) - 1; /* Don't want the final zero */
		data = ldns_rdf_data(label);
		if(ldns_buffer_reserve(buffer, size))
		{
			ldns_buffer_write(buffer, data, size);
		}
		ldns_rdf_deep_free(label);
		s = ldns_dname2buffer_wire_compress(buffer, rest, compression_data);
		ldns_rdf_deep_free(rest);
		return s;
	}
}

ldns_status
ldns_rdf2buffer_wire(ldns_buffer *buffer, const ldns_rdf *rdf)
{
	return ldns_rdf2buffer_wire_compress(buffer, rdf, NULL);
}

ldns_status
ldns_rdf2buffer_wire_compress(ldns_buffer *buffer, const ldns_rdf *rdf, ldns_rbtree_t *compression_data)
{
	/* If it's a DNAME, call that function to get compression */
	if(compression_data && ldns_rdf_get_type(rdf) == LDNS_RDF_TYPE_DNAME)
	{
		return ldns_dname2buffer_wire_compress(buffer,rdf,compression_data);
	}

	if (ldns_buffer_reserve(buffer, ldns_rdf_size(rdf))) {
		ldns_buffer_write(buffer, ldns_rdf_data(rdf), ldns_rdf_size(rdf));
	}
	return ldns_buffer_status(buffer);
}

ldns_status
ldns_rdf2buffer_wire_canonical(ldns_buffer *buffer, const ldns_rdf *rdf)
{
	size_t i;
	uint8_t *rdf_data;

	if (ldns_rdf_get_type(rdf) == LDNS_RDF_TYPE_DNAME) {
		if (ldns_buffer_reserve(buffer, ldns_rdf_size(rdf))) {
			rdf_data = ldns_rdf_data(rdf);
			for (i = 0; i < ldns_rdf_size(rdf); i++) {
				ldns_buffer_write_u8(buffer,
				    (uint8_t) LDNS_DNAME_NORMALIZE((int)rdf_data[i]));
			}
		}
	} else {
		/* direct copy for all other types */
		if (ldns_buffer_reserve(buffer, ldns_rdf_size(rdf))) {
			ldns_buffer_write(buffer,
						   ldns_rdf_data(rdf),
						   ldns_rdf_size(rdf));
		}
	}
	return ldns_buffer_status(buffer);
}

/* convert a rr list to wireformat */
ldns_status
ldns_rr_list2buffer_wire(ldns_buffer *buffer,const ldns_rr_list *rr_list)
{
	uint16_t rr_count;
	uint16_t i;

	rr_count = ldns_rr_list_rr_count(rr_list);
	for(i = 0; i < rr_count; i++) {
		(void)ldns_rr2buffer_wire(buffer, ldns_rr_list_rr(rr_list, i), 
					  LDNS_SECTION_ANY);
	}
	return ldns_buffer_status(buffer);
}


ldns_status
ldns_rr2buffer_wire_canonical(ldns_buffer *buffer,
						const ldns_rr *rr,
						int section)
{
	uint16_t i;
	uint16_t rdl_pos = 0;
	bool pre_rfc3597 = false;
	switch (ldns_rr_get_type(rr)) {
	case LDNS_RR_TYPE_NS:
	case LDNS_RR_TYPE_MD:
	case LDNS_RR_TYPE_MF:
	case LDNS_RR_TYPE_CNAME:
	case LDNS_RR_TYPE_SOA:
	case LDNS_RR_TYPE_MB:
	case LDNS_RR_TYPE_MG:
	case LDNS_RR_TYPE_MR:
	case LDNS_RR_TYPE_PTR:
	case LDNS_RR_TYPE_HINFO:
	case LDNS_RR_TYPE_MINFO:
	case LDNS_RR_TYPE_MX:
	case LDNS_RR_TYPE_RP:
	case LDNS_RR_TYPE_AFSDB:
	case LDNS_RR_TYPE_RT:
	case LDNS_RR_TYPE_SIG:
	case LDNS_RR_TYPE_PX:
	case LDNS_RR_TYPE_NXT:
	case LDNS_RR_TYPE_NAPTR:
	case LDNS_RR_TYPE_KX:
	case LDNS_RR_TYPE_SRV:
	case LDNS_RR_TYPE_DNAME:
	case LDNS_RR_TYPE_A6:
	case LDNS_RR_TYPE_RRSIG:
		pre_rfc3597 = true;
		break;
	default:
		break;
	}
	
	if (ldns_rr_owner(rr)) {
		(void) ldns_rdf2buffer_wire_canonical(buffer, ldns_rr_owner(rr));
	}
	
	if (ldns_buffer_reserve(buffer, 4)) {
		(void) ldns_buffer_write_u16(buffer, ldns_rr_get_type(rr));
		(void) ldns_buffer_write_u16(buffer, ldns_rr_get_class(rr));
	}

	if (section != LDNS_SECTION_QUESTION) {
		if (ldns_buffer_reserve(buffer, 6)) {
			ldns_buffer_write_u32(buffer, ldns_rr_ttl(rr));
			/* remember pos for later */
			rdl_pos = ldns_buffer_position(buffer);
			ldns_buffer_write_u16(buffer, 0);
		}	
		for (i = 0; i < ldns_rr_rd_count(rr); i++) {
			if (pre_rfc3597) {
				(void) ldns_rdf2buffer_wire_canonical(
					buffer, ldns_rr_rdf(rr, i));
			} else {
				(void) ldns_rdf2buffer_wire(
					buffer, ldns_rr_rdf(rr, i));
			}
		}
		if (rdl_pos != 0) {
			ldns_buffer_write_u16_at(buffer, rdl_pos,
			                         ldns_buffer_position(buffer)
		        	                   - rdl_pos - 2);
		}
	}
	return ldns_buffer_status(buffer);
}

ldns_status
ldns_rr2buffer_wire(ldns_buffer *buffer, const ldns_rr *rr, int section)
{
	return ldns_rr2buffer_wire_compress(buffer,rr,section,NULL);
}

ldns_status
ldns_rr2buffer_wire_compress(ldns_buffer *buffer, const ldns_rr *rr, int section, ldns_rbtree_t *compression_data)
{
	uint16_t i;
	uint16_t rdl_pos = 0;

	if (ldns_rr_owner(rr)) {
		(void) ldns_dname2buffer_wire_compress(buffer, ldns_rr_owner(rr), compression_data);
	}
	
	if (ldns_buffer_reserve(buffer, 4)) {
		(void) ldns_buffer_write_u16(buffer, ldns_rr_get_type(rr));
		(void) ldns_buffer_write_u16(buffer, ldns_rr_get_class(rr));
	}

	if (section != LDNS_SECTION_QUESTION) {
		if (ldns_buffer_reserve(buffer, 6)) {
			ldns_buffer_write_u32(buffer, ldns_rr_ttl(rr));
			/* remember pos for later */
			rdl_pos = ldns_buffer_position(buffer);
			ldns_buffer_write_u16(buffer, 0);
		}
		if (LDNS_RR_COMPRESS ==
		    ldns_rr_descript(ldns_rr_get_type(rr))->_compress) {

			for (i = 0; i < ldns_rr_rd_count(rr); i++) {
				(void) ldns_rdf2buffer_wire_compress(buffer,
				    ldns_rr_rdf(rr, i), compression_data);
			}
		} else {
			for (i = 0; i < ldns_rr_rd_count(rr); i++) {
				(void) ldns_rdf2buffer_wire(
				    buffer, ldns_rr_rdf(rr, i));
			}
		}
		if (rdl_pos != 0) {
			ldns_buffer_write_u16_at(buffer, rdl_pos,
			                         ldns_buffer_position(buffer)
		        	                   - rdl_pos - 2);
		}
	}
	return ldns_buffer_status(buffer);
}

ldns_status
ldns_rrsig2buffer_wire(ldns_buffer *buffer, const ldns_rr *rr)
{
	uint16_t i;

	/* it must be a sig RR */
	if (ldns_rr_get_type(rr) != LDNS_RR_TYPE_RRSIG) {
		return LDNS_STATUS_ERR;
	}
	
	/* Convert all the rdfs, except the actual signature data
	 * rdf number 8  - the last, hence: -1 */
	for (i = 0; i < ldns_rr_rd_count(rr) - 1; i++) {
		(void) ldns_rdf2buffer_wire_canonical(buffer, 
				ldns_rr_rdf(rr, i));
	}

	return ldns_buffer_status(buffer);
}

ldns_status
ldns_rr_rdata2buffer_wire(ldns_buffer *buffer, const ldns_rr *rr)
{
	uint16_t i;

	/* convert all the rdf's */
	for (i = 0; i < ldns_rr_rd_count(rr); i++) {
		(void) ldns_rdf2buffer_wire(buffer, ldns_rr_rdf(rr,i));
	}
	return ldns_buffer_status(buffer);
}

/*
 * Copies the packet header data to the buffer in wire format
 */
static ldns_status
ldns_hdr2buffer_wire(ldns_buffer *buffer, const ldns_pkt *packet)
{
	uint8_t flags;
	uint16_t arcount;

	if (ldns_buffer_reserve(buffer, 12)) {
		ldns_buffer_write_u16(buffer, ldns_pkt_id(packet));
		
		flags = ldns_pkt_qr(packet) << 7
		        | ldns_pkt_get_opcode(packet) << 3
		        | ldns_pkt_aa(packet) << 2
		        | ldns_pkt_tc(packet) << 1 | ldns_pkt_rd(packet);
		ldns_buffer_write_u8(buffer, flags);
		
		flags = ldns_pkt_ra(packet) << 7
		        /*| ldns_pkt_z(packet) << 6*/
		        | ldns_pkt_ad(packet) << 5
		        | ldns_pkt_cd(packet) << 4
			| ldns_pkt_get_rcode(packet);
		ldns_buffer_write_u8(buffer, flags);
		
		ldns_buffer_write_u16(buffer, ldns_pkt_qdcount(packet));
		ldns_buffer_write_u16(buffer, ldns_pkt_ancount(packet));
		ldns_buffer_write_u16(buffer, ldns_pkt_nscount(packet));
		/* add EDNS0 and TSIG to additional if they are there */
		arcount = ldns_pkt_arcount(packet);
		if (ldns_pkt_tsig(packet)) {
			arcount++;
		}
		if (ldns_pkt_edns(packet)) {
			arcount++;
		}
		ldns_buffer_write_u16(buffer, arcount);
	}
	
	return ldns_buffer_status(buffer);
}

static void
compression_node_free(ldns_rbnode_t *node, void *arg)
{
	(void)arg; /* Yes, dear compiler, it is used */
	ldns_rdf_deep_free((ldns_rdf *)node->key);
	LDNS_FREE(node);
}

ldns_status
ldns_pkt2buffer_wire(ldns_buffer *buffer, const ldns_pkt *packet)
{
	ldns_status status;
	ldns_rbtree_t *compression_data = ldns_rbtree_create((int (*)(const void *, const void *))ldns_dname_compare);

	status = ldns_pkt2buffer_wire_compress(buffer, packet, compression_data);

	ldns_traverse_postorder(compression_data,compression_node_free,NULL);
	ldns_rbtree_free(compression_data);

	return status;
}

ldns_status
ldns_pkt2buffer_wire_compress(ldns_buffer *buffer, const ldns_pkt *packet, ldns_rbtree_t *compression_data)
{
	ldns_rr_list *rr_list;
	uint16_t i;

	/* edns tmp vars */
	ldns_rr *edns_rr;
	uint8_t edata[4];

	(void) ldns_hdr2buffer_wire(buffer, packet);

	rr_list = ldns_pkt_question(packet);
	if (rr_list) {
		for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
			(void) ldns_rr2buffer_wire_compress(buffer, 
			             ldns_rr_list_rr(rr_list, i), LDNS_SECTION_QUESTION, compression_data);
		}
	}
	rr_list = ldns_pkt_answer(packet);
	if (rr_list) {
		for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
			(void) ldns_rr2buffer_wire_compress(buffer, 
			             ldns_rr_list_rr(rr_list, i), LDNS_SECTION_ANSWER, compression_data);
		}
	}
	rr_list = ldns_pkt_authority(packet);
	if (rr_list) {
		for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
			(void) ldns_rr2buffer_wire_compress(buffer, 
			             ldns_rr_list_rr(rr_list, i), LDNS_SECTION_AUTHORITY, compression_data);
		}
	}
	rr_list = ldns_pkt_additional(packet);
	if (rr_list) {
		for (i = 0; i < ldns_rr_list_rr_count(rr_list); i++) {
			(void) ldns_rr2buffer_wire_compress(buffer, 
			             ldns_rr_list_rr(rr_list, i), LDNS_SECTION_ADDITIONAL, compression_data);
		}
	}
	
	/* add EDNS to additional if it is needed */
	if (ldns_pkt_edns(packet)) {
		edns_rr = ldns_rr_new();
		if(!edns_rr) return LDNS_STATUS_MEM_ERR;
		ldns_rr_set_owner(edns_rr,
				ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, "."));
		ldns_rr_set_type(edns_rr, LDNS_RR_TYPE_OPT);
		ldns_rr_set_class(edns_rr, ldns_pkt_edns_udp_size(packet));
		edata[0] = ldns_pkt_edns_extended_rcode(packet);
		edata[1] = ldns_pkt_edns_version(packet);
		ldns_write_uint16(&edata[2], ldns_pkt_edns_z(packet));
		ldns_rr_set_ttl(edns_rr, ldns_read_uint32(edata));
		/* don't forget to add the edns rdata (if any) */
		if (packet->_edns_data)
			ldns_rr_push_rdf (edns_rr, packet->_edns_data);
		(void)ldns_rr2buffer_wire_compress(buffer, edns_rr, LDNS_SECTION_ADDITIONAL, compression_data);
		/* take the edns rdata back out of the rr before we free rr */
		if (packet->_edns_data)
			(void)ldns_rr_pop_rdf (edns_rr);
		ldns_rr_free(edns_rr);
	}
	
	/* add TSIG to additional if it is there */
	if (ldns_pkt_tsig(packet)) {
		(void) ldns_rr2buffer_wire_compress(buffer,
		                           ldns_pkt_tsig(packet), LDNS_SECTION_ADDITIONAL, compression_data);
	}

	return LDNS_STATUS_OK;
}

ldns_status
ldns_rdf2wire(uint8_t **dest, const ldns_rdf *rdf, size_t *result_size)
{
	ldns_buffer *buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN);
	ldns_status status;
	*result_size = 0;
	*dest = NULL;
	if(!buffer) return LDNS_STATUS_MEM_ERR;
	
	status = ldns_rdf2buffer_wire(buffer, rdf);
	if (status == LDNS_STATUS_OK) {
		*result_size =  ldns_buffer_position(buffer);
		*dest = (uint8_t *) ldns_buffer_export(buffer);
	}
	ldns_buffer_free(buffer);
	return status;
}

ldns_status
ldns_rr2wire(uint8_t **dest, const ldns_rr *rr, int section, size_t *result_size)
{
	ldns_buffer *buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN);
	ldns_status status;
	*result_size = 0;
	*dest = NULL;
	if(!buffer) return LDNS_STATUS_MEM_ERR;
	
	status = ldns_rr2buffer_wire(buffer, rr, section);
	if (status == LDNS_STATUS_OK) {
		*result_size =  ldns_buffer_position(buffer);
		*dest = (uint8_t *) ldns_buffer_export(buffer);
	}
	ldns_buffer_free(buffer);
	return status;
}

ldns_status
ldns_pkt2wire(uint8_t **dest, const ldns_pkt *packet, size_t *result_size)
{
	ldns_buffer *buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN);
	ldns_status status;
	*result_size = 0;
	*dest = NULL;
	if(!buffer) return LDNS_STATUS_MEM_ERR;
	
	status = ldns_pkt2buffer_wire(buffer, packet);
	if (status == LDNS_STATUS_OK) {
		*result_size =  ldns_buffer_position(buffer);
		*dest = (uint8_t *) ldns_buffer_export(buffer);
	}
	ldns_buffer_free(buffer);
	return status;
}