host2wire.c

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/*
 * 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;
}