/*
* wire2host.c
*
* conversion routines from the wire to the host
* 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>
/*#include <ldns/wire2host.h>*/
#include <strings.h>
#include <limits.h>
/*
* Set of macro's to deal with the dns message header as specified
* in RFC1035 in portable way.
*
*/
/*
*
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ID |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* |QR| Opcode |AA|TC|RD|RA| Z|AD|CD| RCODE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QDCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ANCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | NSCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ARCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*
*/
/* allocates memory to *dname! */
ldns_status
ldns_wire2dname(ldns_rdf **dname, const uint8_t *wire, size_t max, size_t *pos)
{
uint8_t label_size;
uint16_t pointer_target;
uint8_t pointer_target_buf[2];
size_t dname_pos = 0;
size_t uncompressed_length = 0;
size_t compression_pos = 0;
uint8_t tmp_dname[LDNS_MAX_DOMAINLEN];
unsigned int pointer_count = 0;
if (*pos >= max) {
return LDNS_STATUS_PACKET_OVERFLOW;
}
label_size = wire[*pos];
while (label_size > 0) {
/* compression */
if (label_size >= 192) {
if (compression_pos == 0) {
compression_pos = *pos + 2;
}
pointer_count++;
/* remove first two bits */
if (*pos + 2 > max) {
return LDNS_STATUS_PACKET_OVERFLOW;
}
pointer_target_buf[0] = wire[*pos] & 63;
pointer_target_buf[1] = wire[*pos + 1];
pointer_target = ldns_read_uint16(pointer_target_buf);
if (pointer_target == 0) {
return LDNS_STATUS_INVALID_POINTER;
} else if (pointer_target > max) {
return LDNS_STATUS_INVALID_POINTER;
} else if (pointer_count > LDNS_MAX_POINTERS) {
return LDNS_STATUS_INVALID_POINTER;
}
*pos = pointer_target;
label_size = wire[*pos];
}
if (label_size > LDNS_MAX_LABELLEN) {
return LDNS_STATUS_LABEL_OVERFLOW;
}
if (*pos + label_size > max) {
return LDNS_STATUS_LABEL_OVERFLOW;
}
tmp_dname[dname_pos] = label_size;
dname_pos++;
*pos = *pos + 1;
memcpy(&tmp_dname[dname_pos], &wire[*pos], label_size);
uncompressed_length += label_size + 1;
dname_pos += label_size;
*pos = *pos + label_size;
if (dname_pos > LDNS_MAX_DOMAINLEN) {
return LDNS_STATUS_DOMAINNAME_OVERFLOW;
}
if (*pos < max) {
label_size = wire[*pos];
}
}
if (compression_pos > 0) {
*pos = compression_pos;
} else {
*pos = *pos + 1;
}
tmp_dname[dname_pos] = 0;
dname_pos++;
*dname = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME,
(uint16_t) dname_pos, tmp_dname);
if (!*dname) {
return LDNS_STATUS_MEM_ERR;
}
return LDNS_STATUS_OK;
}
/* maybe make this a goto error so data can be freed or something/ */
#define LDNS_STATUS_CHECK_RETURN(st) {if (st != LDNS_STATUS_OK) { return st; }}
#define LDNS_STATUS_CHECK_GOTO(st, label) {if (st != LDNS_STATUS_OK) { /*printf("STG %s:%d: status code %d\n", __FILE__, __LINE__, st);*/ goto label; }}
ldns_status
ldns_wire2rdf(ldns_rr *rr, const uint8_t *wire, size_t max, size_t *pos)
{
size_t end;
size_t cur_rdf_length;
uint8_t rdf_index;
uint8_t *data;
uint16_t rd_length;
ldns_rdf *cur_rdf;
ldns_rdf_type cur_rdf_type;
const ldns_rr_descriptor *descriptor = ldns_rr_descript(ldns_rr_get_type(rr));
ldns_status status;
if (*pos + 2 > max) {
return LDNS_STATUS_PACKET_OVERFLOW;
}
rd_length = ldns_read_uint16(&wire[*pos]);
*pos = *pos + 2;
if (*pos + rd_length > max) {
return LDNS_STATUS_PACKET_OVERFLOW;
}
end = *pos + (size_t) rd_length;
for (rdf_index = 0;
rdf_index < ldns_rr_descriptor_maximum(descriptor); rdf_index++) {
if (*pos >= end) {
break;
}
cur_rdf_length = 0;
cur_rdf_type = ldns_rr_descriptor_field_type(descriptor, rdf_index);
/* handle special cases immediately, set length
for fixed length rdata and do them below */
switch (cur_rdf_type) {
case LDNS_RDF_TYPE_DNAME:
status = ldns_wire2dname(&cur_rdf, wire, max, pos);
LDNS_STATUS_CHECK_RETURN(status);
break;
case LDNS_RDF_TYPE_CLASS:
case LDNS_RDF_TYPE_ALG:
case LDNS_RDF_TYPE_INT8:
cur_rdf_length = LDNS_RDF_SIZE_BYTE;
break;
case LDNS_RDF_TYPE_TYPE:
case LDNS_RDF_TYPE_INT16:
case LDNS_RDF_TYPE_CERT_ALG:
cur_rdf_length = LDNS_RDF_SIZE_WORD;
break;
case LDNS_RDF_TYPE_TIME:
case LDNS_RDF_TYPE_INT32:
case LDNS_RDF_TYPE_A:
case LDNS_RDF_TYPE_PERIOD:
cur_rdf_length = LDNS_RDF_SIZE_DOUBLEWORD;
break;
case LDNS_RDF_TYPE_TSIGTIME:
cur_rdf_length = LDNS_RDF_SIZE_6BYTES;
break;
case LDNS_RDF_TYPE_AAAA:
cur_rdf_length = LDNS_RDF_SIZE_16BYTES;
break;
case LDNS_RDF_TYPE_STR:
/* len is stored in first byte
* it should be in the rdf too, so just
* copy len+1 from this position
*/
cur_rdf_length = ((size_t) wire[*pos]) + 1;
break;
case LDNS_RDF_TYPE_INT16_DATA:
cur_rdf_length = (size_t) ldns_read_uint16(&wire[*pos]) + 2;
break;
case LDNS_RDF_TYPE_APL:
case LDNS_RDF_TYPE_B64:
case LDNS_RDF_TYPE_HEX:
case LDNS_RDF_TYPE_NSEC:
case LDNS_RDF_TYPE_UNKNOWN:
case LDNS_RDF_TYPE_SERVICE:
case LDNS_RDF_TYPE_LOC:
case LDNS_RDF_TYPE_WKS:
case LDNS_RDF_TYPE_NSAP:
case LDNS_RDF_TYPE_IPSECKEY:
case LDNS_RDF_TYPE_TSIG:
case LDNS_RDF_TYPE_NONE:
/*
* Read to end of rr rdata
*/
cur_rdf_length = end - *pos;
break;
}
/* fixed length rdata */
if (cur_rdf_length > 0) {
data = LDNS_XMALLOC(uint8_t, rd_length);
if (!data) {
return LDNS_STATUS_MEM_ERR;
}
memcpy(data, &wire[*pos], cur_rdf_length);
cur_rdf = ldns_rdf_new(cur_rdf_type, cur_rdf_length, data);
*pos = *pos + cur_rdf_length;
}
ldns_rr_push_rdf(rr, cur_rdf);
}
return LDNS_STATUS_OK;
}
/* TODO:
can *pos be incremented at READ_INT? or maybe use something like
RR_CLASS(wire)?
uhhm Jelte??
*/
ldns_status
ldns_wire2rr(ldns_rr **rr_p, const uint8_t *wire, size_t max,
size_t *pos, ldns_pkt_section section)
{
ldns_rdf *owner;
ldns_rr *rr = ldns_rr_new();
ldns_status status;
status = ldns_wire2dname(&owner, wire, max, pos);
LDNS_STATUS_CHECK_GOTO(status, status_error);
ldns_rr_set_owner(rr, owner);
if (*pos + 4 > max) {
status = LDNS_STATUS_PACKET_OVERFLOW;
goto status_error;
}
ldns_rr_set_type(rr, ldns_read_uint16(&wire[*pos]));
*pos = *pos + 2;
ldns_rr_set_class(rr, ldns_read_uint16(&wire[*pos]));
*pos = *pos + 2;
if (section != LDNS_SECTION_QUESTION) {
if (*pos + 4 > max) {
status = LDNS_STATUS_PACKET_OVERFLOW;
goto status_error;
}
ldns_rr_set_ttl(rr, ldns_read_uint32(&wire[*pos]));
*pos = *pos + 4;
status = ldns_wire2rdf(rr, wire, max, pos);
LDNS_STATUS_CHECK_GOTO(status, status_error);
}
*rr_p = rr;
return LDNS_STATUS_OK;
status_error:
ldns_rr_free(rr);
return status;
}
static ldns_status
ldns_wire2pkt_hdr(ldns_pkt *packet, const uint8_t *wire, size_t max, size_t *pos)
{
if (*pos + LDNS_HEADER_SIZE > max) {
return LDNS_STATUS_WIRE_INCOMPLETE_HEADER;
} else {
ldns_pkt_set_id(packet, LDNS_ID_WIRE(wire));
ldns_pkt_set_qr(packet, LDNS_QR_WIRE(wire));
ldns_pkt_set_opcode(packet, LDNS_OPCODE_WIRE(wire));
ldns_pkt_set_aa(packet, LDNS_AA_WIRE(wire));
ldns_pkt_set_tc(packet, LDNS_TC_WIRE(wire));
ldns_pkt_set_rd(packet, LDNS_RD_WIRE(wire));
ldns_pkt_set_ra(packet, LDNS_RA_WIRE(wire));
ldns_pkt_set_ad(packet, LDNS_AD_WIRE(wire));
ldns_pkt_set_cd(packet, LDNS_CD_WIRE(wire));
ldns_pkt_set_rcode(packet, LDNS_RCODE_WIRE(wire));
ldns_pkt_set_qdcount(packet, LDNS_QDCOUNT(wire));
ldns_pkt_set_ancount(packet, LDNS_ANCOUNT(wire));
ldns_pkt_set_nscount(packet, LDNS_NSCOUNT(wire));
ldns_pkt_set_arcount(packet, LDNS_ARCOUNT(wire));
*pos += LDNS_HEADER_SIZE;
return LDNS_STATUS_OK;
}
}
ldns_status
ldns_buffer2pkt_wire(ldns_pkt **packet, ldns_buffer *buffer)
{
/* lazy */
return ldns_wire2pkt(packet, ldns_buffer_begin(buffer),
ldns_buffer_capacity(buffer));
}
ldns_status
ldns_wire2pkt(ldns_pkt **packet_p, const uint8_t *wire, size_t max)
{
size_t pos = 0;
uint16_t i;
ldns_rr *rr;
ldns_pkt *packet = ldns_pkt_new();
ldns_status status = LDNS_STATUS_OK;
uint8_t data[4];
status = ldns_wire2pkt_hdr(packet, wire, max, &pos);
LDNS_STATUS_CHECK_GOTO(status, status_error);
for (i = 0; i < ldns_pkt_qdcount(packet); i++) {
status = ldns_wire2rr(&rr, wire, max, &pos, LDNS_SECTION_QUESTION);
if (status == LDNS_STATUS_PACKET_OVERFLOW) {
status = LDNS_STATUS_WIRE_INCOMPLETE_QUESTION;
}
LDNS_STATUS_CHECK_GOTO(status, status_error);
if (!ldns_rr_list_push_rr(ldns_pkt_question(packet), rr)) {
ldns_pkt_free(packet);
return LDNS_STATUS_INTERNAL_ERR;
}
}
for (i = 0; i < ldns_pkt_ancount(packet); i++) {
status = ldns_wire2rr(&rr, wire, max, &pos, LDNS_SECTION_ANSWER);
if (status == LDNS_STATUS_PACKET_OVERFLOW) {
status = LDNS_STATUS_WIRE_INCOMPLETE_ANSWER;
}
LDNS_STATUS_CHECK_GOTO(status, status_error);
if (!ldns_rr_list_push_rr(ldns_pkt_answer(packet), rr)) {
ldns_pkt_free(packet);
return LDNS_STATUS_INTERNAL_ERR;
}
}
for (i = 0; i < ldns_pkt_nscount(packet); i++) {
status = ldns_wire2rr(&rr, wire, max, &pos, LDNS_SECTION_AUTHORITY);
if (status == LDNS_STATUS_PACKET_OVERFLOW) {
status = LDNS_STATUS_WIRE_INCOMPLETE_AUTHORITY;
}
LDNS_STATUS_CHECK_GOTO(status, status_error);
if (!ldns_rr_list_push_rr(ldns_pkt_authority(packet), rr)) {
ldns_pkt_free(packet);
return LDNS_STATUS_INTERNAL_ERR;
}
}
for (i = 0; i < ldns_pkt_arcount(packet); i++) {
status = ldns_wire2rr(&rr, wire, max, &pos, LDNS_SECTION_ADDITIONAL);
if (status == LDNS_STATUS_PACKET_OVERFLOW) {
status = LDNS_STATUS_WIRE_INCOMPLETE_ADDITIONAL;
}
LDNS_STATUS_CHECK_GOTO(status, status_error);
if (ldns_rr_get_type(rr) == LDNS_RR_TYPE_OPT) {
ldns_pkt_set_edns_udp_size(packet, ldns_rr_get_class(rr));
ldns_write_uint32(data, ldns_rr_ttl(rr));
ldns_pkt_set_edns_extended_rcode(packet, data[0]);
ldns_pkt_set_edns_version(packet, data[1]);
ldns_pkt_set_edns_z(packet, ldns_read_uint16(&data[2]));
/* edns might not have rdfs */
if (ldns_rr_rdf(rr, 0)) {
ldns_pkt_set_edns_data(packet, ldns_rdf_clone(ldns_rr_rdf(rr, 0)));
}
ldns_rr_free(rr);
ldns_pkt_set_arcount(packet, ldns_pkt_arcount(packet) - 1);
} else if (ldns_rr_get_type(rr) == LDNS_RR_TYPE_TSIG) {
ldns_pkt_set_tsig(packet, rr);
ldns_pkt_set_arcount(packet, ldns_pkt_arcount(packet) - 1);
} else if (!ldns_rr_list_push_rr(ldns_pkt_additional(packet), rr)) {
ldns_pkt_free(packet);
return LDNS_STATUS_INTERNAL_ERR;
}
}
ldns_pkt_set_size(packet, max);
*packet_p = packet;
return status;
status_error:
ldns_pkt_free(packet);
return status;
}
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