783 lines
17 KiB
C
783 lines
17 KiB
C
/*
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* util/data/dname.h - domain name handling
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*
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* Copyright (c) 2007, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file contains domain name handling functions.
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*/
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#include "config.h"
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#include <ctype.h>
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#include "util/data/dname.h"
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#include "util/data/msgparse.h"
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#include "util/log.h"
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#include "util/storage/lookup3.h"
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#include "ldns/sbuffer.h"
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/* determine length of a dname in buffer, no compression pointers allowed */
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size_t
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query_dname_len(sldns_buffer* query)
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{
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size_t len = 0;
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size_t labellen;
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while(1) {
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if(sldns_buffer_remaining(query) < 1)
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return 0; /* parse error, need label len */
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labellen = sldns_buffer_read_u8(query);
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if(labellen&0xc0)
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return 0; /* no compression allowed in queries */
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len += labellen + 1;
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if(len > LDNS_MAX_DOMAINLEN)
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return 0; /* too long */
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if(labellen == 0)
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return len;
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if(sldns_buffer_remaining(query) < labellen)
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return 0; /* parse error, need content */
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sldns_buffer_skip(query, (ssize_t)labellen);
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}
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}
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size_t
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dname_valid(uint8_t* dname, size_t maxlen)
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{
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size_t len = 0;
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size_t labellen;
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labellen = *dname++;
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while(labellen) {
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if(labellen&0xc0)
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return 0; /* no compression ptrs allowed */
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len += labellen + 1;
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if(len >= LDNS_MAX_DOMAINLEN)
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return 0; /* too long */
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if(len > maxlen)
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return 0; /* does not fit in memory allocation */
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dname += labellen;
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labellen = *dname++;
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}
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len += 1;
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if(len > maxlen)
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return 0; /* does not fit in memory allocation */
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return len;
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}
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/** compare uncompressed, noncanonical, registers are hints for speed */
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int
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query_dname_compare(register uint8_t* d1, register uint8_t* d2)
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{
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register uint8_t lab1, lab2;
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log_assert(d1 && d2);
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lab1 = *d1++;
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lab2 = *d2++;
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while( lab1 != 0 || lab2 != 0 ) {
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/* compare label length */
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/* if one dname ends, it has labellength 0 */
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if(lab1 != lab2) {
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if(lab1 < lab2)
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return -1;
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return 1;
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}
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log_assert(lab1 == lab2 && lab1 != 0);
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/* compare lowercased labels. */
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while(lab1--) {
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/* compare bytes first for speed */
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if(*d1 != *d2 &&
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tolower((int)*d1) != tolower((int)*d2)) {
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if(tolower((int)*d1) < tolower((int)*d2))
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return -1;
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return 1;
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}
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d1++;
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d2++;
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}
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/* next pair of labels. */
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lab1 = *d1++;
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lab2 = *d2++;
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}
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return 0;
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}
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void
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query_dname_tolower(uint8_t* dname)
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{
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/* the dname is stored uncompressed */
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uint8_t labellen;
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labellen = *dname;
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while(labellen) {
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dname++;
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while(labellen--) {
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*dname = (uint8_t)tolower((int)*dname);
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dname++;
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}
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labellen = *dname;
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}
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}
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void
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pkt_dname_tolower(sldns_buffer* pkt, uint8_t* dname)
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{
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uint8_t lablen;
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int count = 0;
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if(dname >= sldns_buffer_end(pkt))
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return;
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lablen = *dname++;
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while(lablen) {
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if(LABEL_IS_PTR(lablen)) {
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if((size_t)PTR_OFFSET(lablen, *dname)
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>= sldns_buffer_limit(pkt))
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return;
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dname = sldns_buffer_at(pkt, PTR_OFFSET(lablen, *dname));
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lablen = *dname++;
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if(count++ > MAX_COMPRESS_PTRS)
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return;
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continue;
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}
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if(dname+lablen >= sldns_buffer_end(pkt))
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return;
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while(lablen--) {
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*dname = (uint8_t)tolower((int)*dname);
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dname++;
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}
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if(dname >= sldns_buffer_end(pkt))
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return;
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lablen = *dname++;
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}
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}
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size_t
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pkt_dname_len(sldns_buffer* pkt)
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{
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size_t len = 0;
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int ptrcount = 0;
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uint8_t labellen;
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size_t endpos = 0;
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/* read dname and determine length */
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/* check compression pointers, loops, out of bounds */
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while(1) {
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/* read next label */
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if(sldns_buffer_remaining(pkt) < 1)
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return 0;
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labellen = sldns_buffer_read_u8(pkt);
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if(LABEL_IS_PTR(labellen)) {
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/* compression ptr */
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uint16_t ptr;
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if(sldns_buffer_remaining(pkt) < 1)
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return 0;
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ptr = PTR_OFFSET(labellen, sldns_buffer_read_u8(pkt));
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if(ptrcount++ > MAX_COMPRESS_PTRS)
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return 0; /* loop! */
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if(sldns_buffer_limit(pkt) <= ptr)
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return 0; /* out of bounds! */
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if(!endpos)
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endpos = sldns_buffer_position(pkt);
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sldns_buffer_set_position(pkt, ptr);
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} else {
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/* label contents */
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if(labellen > 0x3f)
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return 0; /* label too long */
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len += 1 + labellen;
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if(len > LDNS_MAX_DOMAINLEN)
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return 0;
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if(labellen == 0) {
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/* end of dname */
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break;
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}
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if(sldns_buffer_remaining(pkt) < labellen)
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return 0;
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sldns_buffer_skip(pkt, (ssize_t)labellen);
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}
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}
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if(endpos)
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sldns_buffer_set_position(pkt, endpos);
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return len;
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}
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int
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dname_pkt_compare(sldns_buffer* pkt, uint8_t* d1, uint8_t* d2)
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{
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uint8_t len1, len2;
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log_assert(pkt && d1 && d2);
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len1 = *d1++;
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len2 = *d2++;
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while( len1 != 0 || len2 != 0 ) {
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/* resolve ptrs */
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if(LABEL_IS_PTR(len1)) {
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d1 = sldns_buffer_at(pkt, PTR_OFFSET(len1, *d1));
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len1 = *d1++;
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continue;
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}
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if(LABEL_IS_PTR(len2)) {
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d2 = sldns_buffer_at(pkt, PTR_OFFSET(len2, *d2));
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len2 = *d2++;
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continue;
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}
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/* check label length */
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log_assert(len1 <= LDNS_MAX_LABELLEN);
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log_assert(len2 <= LDNS_MAX_LABELLEN);
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if(len1 != len2) {
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if(len1 < len2) return -1;
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return 1;
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}
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log_assert(len1 == len2 && len1 != 0);
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/* compare labels */
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while(len1--) {
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if(tolower((int)*d1++) != tolower((int)*d2++)) {
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if(tolower((int)d1[-1]) < tolower((int)d2[-1]))
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return -1;
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return 1;
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}
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}
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len1 = *d1++;
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len2 = *d2++;
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}
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return 0;
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}
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hashvalue_t
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dname_query_hash(uint8_t* dname, hashvalue_t h)
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{
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uint8_t labuf[LDNS_MAX_LABELLEN+1];
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uint8_t lablen;
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int i;
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/* preserve case of query, make hash label by label */
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lablen = *dname++;
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while(lablen) {
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log_assert(lablen <= LDNS_MAX_LABELLEN);
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labuf[0] = lablen;
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i=0;
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while(lablen--)
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labuf[++i] = (uint8_t)tolower((int)*dname++);
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h = hashlittle(labuf, labuf[0] + 1, h);
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lablen = *dname++;
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}
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return h;
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}
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hashvalue_t
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dname_pkt_hash(sldns_buffer* pkt, uint8_t* dname, hashvalue_t h)
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{
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uint8_t labuf[LDNS_MAX_LABELLEN+1];
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uint8_t lablen;
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int i;
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/* preserve case of query, make hash label by label */
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lablen = *dname++;
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while(lablen) {
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if(LABEL_IS_PTR(lablen)) {
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/* follow pointer */
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dname = sldns_buffer_at(pkt, PTR_OFFSET(lablen, *dname));
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lablen = *dname++;
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continue;
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}
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log_assert(lablen <= LDNS_MAX_LABELLEN);
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labuf[0] = lablen;
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i=0;
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while(lablen--)
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labuf[++i] = (uint8_t)tolower((int)*dname++);
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h = hashlittle(labuf, labuf[0] + 1, h);
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lablen = *dname++;
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}
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return h;
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}
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void dname_pkt_copy(sldns_buffer* pkt, uint8_t* to, uint8_t* dname)
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{
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/* copy over the dname and decompress it at the same time */
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size_t len = 0;
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uint8_t lablen;
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lablen = *dname++;
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while(lablen) {
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if(LABEL_IS_PTR(lablen)) {
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/* follow pointer */
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dname = sldns_buffer_at(pkt, PTR_OFFSET(lablen, *dname));
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lablen = *dname++;
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continue;
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}
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log_assert(lablen <= LDNS_MAX_LABELLEN);
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len += (size_t)lablen+1;
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if(len >= LDNS_MAX_DOMAINLEN) {
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*to = 0; /* end the result prematurely */
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log_err("bad dname in dname_pkt_copy");
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return;
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}
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*to++ = lablen;
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memmove(to, dname, lablen);
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dname += lablen;
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to += lablen;
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lablen = *dname++;
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}
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/* copy last \0 */
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*to = 0;
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}
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void dname_print(FILE* out, struct sldns_buffer* pkt, uint8_t* dname)
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{
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uint8_t lablen;
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if(!out) out = stdout;
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if(!dname) return;
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lablen = *dname++;
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if(!lablen)
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fputc('.', out);
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while(lablen) {
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if(LABEL_IS_PTR(lablen)) {
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/* follow pointer */
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if(!pkt) {
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fputs("??compressionptr??", out);
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return;
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}
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dname = sldns_buffer_at(pkt, PTR_OFFSET(lablen, *dname));
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lablen = *dname++;
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continue;
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}
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if(lablen > LDNS_MAX_LABELLEN) {
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fputs("??extendedlabel??", out);
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return;
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}
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while(lablen--)
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fputc((int)*dname++, out);
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fputc('.', out);
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lablen = *dname++;
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}
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}
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int
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dname_count_labels(uint8_t* dname)
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{
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uint8_t lablen;
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int labs = 1;
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lablen = *dname++;
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while(lablen) {
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labs++;
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dname += lablen;
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lablen = *dname++;
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}
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return labs;
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}
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int
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dname_count_size_labels(uint8_t* dname, size_t* size)
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{
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uint8_t lablen;
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int labs = 1;
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size_t sz = 1;
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lablen = *dname++;
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while(lablen) {
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labs++;
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sz += lablen+1;
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dname += lablen;
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lablen = *dname++;
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}
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*size = sz;
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return labs;
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}
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/**
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* Compare labels in memory, lowercase while comparing.
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* @param p1: label 1
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* @param p2: label 2
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* @param len: number of bytes to compare.
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* @return: 0, -1, +1 comparison result.
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*/
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static int
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memlowercmp(uint8_t* p1, uint8_t* p2, uint8_t len)
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{
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while(len--) {
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if(*p1 != *p2 && tolower((int)*p1) != tolower((int)*p2)) {
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if(tolower((int)*p1) < tolower((int)*p2))
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return -1;
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return 1;
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}
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p1++;
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p2++;
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}
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return 0;
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}
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int
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dname_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, int* mlabs)
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{
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uint8_t len1, len2;
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int atlabel = labs1;
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int lastmlabs;
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int lastdiff = 0;
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/* first skip so that we compare same label. */
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if(labs1 > labs2) {
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while(atlabel > labs2) {
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len1 = *d1++;
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d1 += len1;
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atlabel--;
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}
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log_assert(atlabel == labs2);
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} else if(labs1 < labs2) {
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atlabel = labs2;
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while(atlabel > labs1) {
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len2 = *d2++;
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d2 += len2;
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atlabel--;
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}
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log_assert(atlabel == labs1);
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}
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lastmlabs = atlabel+1;
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/* now at same label in d1 and d2, atlabel */
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/* www.example.com. */
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/* 4 3 2 1 atlabel number */
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/* repeat until at root label (which is always the same) */
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while(atlabel > 1) {
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len1 = *d1++;
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len2 = *d2++;
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if(len1 != len2) {
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log_assert(len1 != 0 && len2 != 0);
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if(len1<len2)
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lastdiff = -1;
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else lastdiff = 1;
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lastmlabs = atlabel;
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d1 += len1;
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d2 += len2;
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} else {
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/* memlowercmp is inlined here; or just like
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* if((c=memlowercmp(d1, d2, len1)) != 0) {
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* lastdiff = c;
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* lastmlabs = atlabel; } apart from d1++,d2++ */
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while(len1) {
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if(*d1 != *d2 && tolower((int)*d1)
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!= tolower((int)*d2)) {
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if(tolower((int)*d1) <
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tolower((int)*d2)) {
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lastdiff = -1;
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lastmlabs = atlabel;
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d1 += len1;
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d2 += len1;
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break;
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}
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lastdiff = 1;
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lastmlabs = atlabel;
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d1 += len1;
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d2 += len1;
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break; /* out of memlowercmp */
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}
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d1++;
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d2++;
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len1--;
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}
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}
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atlabel--;
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}
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/* last difference atlabel number, so number of labels matching,
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* at the right side, is one less. */
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*mlabs = lastmlabs-1;
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if(lastdiff == 0) {
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/* all labels compared were equal, check if one has more
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* labels, so that example.com. > com. */
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if(labs1 > labs2)
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return 1;
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else if(labs1 < labs2)
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return -1;
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}
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return lastdiff;
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}
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int
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dname_buffer_write(sldns_buffer* pkt, uint8_t* dname)
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{
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uint8_t lablen;
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if(sldns_buffer_remaining(pkt) < 1)
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return 0;
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lablen = *dname++;
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|
sldns_buffer_write_u8(pkt, lablen);
|
|
while(lablen) {
|
|
if(sldns_buffer_remaining(pkt) < (size_t)lablen+1)
|
|
return 0;
|
|
sldns_buffer_write(pkt, dname, lablen);
|
|
dname += lablen;
|
|
lablen = *dname++;
|
|
sldns_buffer_write_u8(pkt, lablen);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
void dname_str(uint8_t* dname, char* str)
|
|
{
|
|
size_t len = 0;
|
|
uint8_t lablen = 0;
|
|
char* s = str;
|
|
if(!dname || !*dname) {
|
|
*s++ = '.';
|
|
*s = 0;
|
|
return;
|
|
}
|
|
lablen = *dname++;
|
|
while(lablen) {
|
|
if(lablen > LDNS_MAX_LABELLEN) {
|
|
*s++ = '#';
|
|
*s = 0;
|
|
return;
|
|
}
|
|
len += lablen+1;
|
|
if(len >= LDNS_MAX_DOMAINLEN-1) {
|
|
*s++ = '&';
|
|
*s = 0;
|
|
return;
|
|
}
|
|
while(lablen--) {
|
|
if(isalnum((int)*dname)
|
|
|| *dname == '-' || *dname == '_'
|
|
|| *dname == '*')
|
|
*s++ = *(char*)dname++;
|
|
else {
|
|
*s++ = '?';
|
|
dname++;
|
|
}
|
|
}
|
|
*s++ = '.';
|
|
lablen = *dname++;
|
|
}
|
|
*s = 0;
|
|
}
|
|
|
|
int
|
|
dname_strict_subdomain(uint8_t* d1, int labs1, uint8_t* d2, int labs2)
|
|
{
|
|
int m;
|
|
/* check subdomain: d1: www.example.com. and d2: example.com. */
|
|
if(labs2 >= labs1)
|
|
return 0;
|
|
if(dname_lab_cmp(d1, labs1, d2, labs2, &m) > 0) {
|
|
/* subdomain if all labels match */
|
|
return (m == labs2);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
dname_strict_subdomain_c(uint8_t* d1, uint8_t* d2)
|
|
{
|
|
return dname_strict_subdomain(d1, dname_count_labels(d1), d2,
|
|
dname_count_labels(d2));
|
|
}
|
|
|
|
int
|
|
dname_subdomain_c(uint8_t* d1, uint8_t* d2)
|
|
{
|
|
int m;
|
|
/* check subdomain: d1: www.example.com. and d2: example.com. */
|
|
/* or d1: example.com. and d2: example.com. */
|
|
int labs1 = dname_count_labels(d1);
|
|
int labs2 = dname_count_labels(d2);
|
|
if(labs2 > labs1)
|
|
return 0;
|
|
if(dname_lab_cmp(d1, labs1, d2, labs2, &m) < 0) {
|
|
/* must have been example.com , www.example.com - wrong */
|
|
/* or otherwise different dnames */
|
|
return 0;
|
|
}
|
|
return (m == labs2);
|
|
}
|
|
|
|
int
|
|
dname_is_root(uint8_t* dname)
|
|
{
|
|
uint8_t len;
|
|
log_assert(dname);
|
|
len = dname[0];
|
|
log_assert(!LABEL_IS_PTR(len));
|
|
return (len == 0);
|
|
}
|
|
|
|
void
|
|
dname_remove_label(uint8_t** dname, size_t* len)
|
|
{
|
|
size_t lablen;
|
|
log_assert(dname && *dname && len);
|
|
lablen = (*dname)[0];
|
|
log_assert(!LABEL_IS_PTR(lablen));
|
|
log_assert(*len > lablen);
|
|
if(lablen == 0)
|
|
return; /* do not modify root label */
|
|
*len -= lablen+1;
|
|
*dname += lablen+1;
|
|
}
|
|
|
|
void
|
|
dname_remove_labels(uint8_t** dname, size_t* len, int n)
|
|
{
|
|
int i;
|
|
for(i=0; i<n; i++)
|
|
dname_remove_label(dname, len);
|
|
}
|
|
|
|
int
|
|
dname_signame_label_count(uint8_t* dname)
|
|
{
|
|
uint8_t lablen;
|
|
int count = 0;
|
|
if(!*dname)
|
|
return 0;
|
|
if(dname[0] == 1 && dname[1] == '*')
|
|
dname += 2;
|
|
lablen = dname[0];
|
|
while(lablen) {
|
|
count++;
|
|
dname += lablen;
|
|
dname += 1;
|
|
lablen = dname[0];
|
|
}
|
|
return count;
|
|
}
|
|
|
|
int
|
|
dname_is_wild(uint8_t* dname)
|
|
{
|
|
return (dname[0] == 1 && dname[1] == '*');
|
|
}
|
|
|
|
/**
|
|
* Compare labels in memory, lowercase while comparing.
|
|
* Returns canonical order for labels. If all is equal, the
|
|
* shortest is first.
|
|
*
|
|
* @param p1: label 1
|
|
* @param len1: length of label 1.
|
|
* @param p2: label 2
|
|
* @param len2: length of label 2.
|
|
* @return: 0, -1, +1 comparison result.
|
|
*/
|
|
static int
|
|
memcanoncmp(uint8_t* p1, uint8_t len1, uint8_t* p2, uint8_t len2)
|
|
{
|
|
uint8_t min = (len1<len2)?len1:len2;
|
|
int c = memlowercmp(p1, p2, min);
|
|
if(c != 0)
|
|
return c;
|
|
/* equal, see who is shortest */
|
|
if(len1 < len2)
|
|
return -1;
|
|
if(len1 > len2)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
|
|
int
|
|
dname_canon_lab_cmp(uint8_t* d1, int labs1, uint8_t* d2, int labs2, int* mlabs)
|
|
{
|
|
/* like dname_lab_cmp, but with different label comparison,
|
|
* empty character sorts before \000.
|
|
* So ylyly is before z. */
|
|
uint8_t len1, len2;
|
|
int atlabel = labs1;
|
|
int lastmlabs;
|
|
int lastdiff = 0;
|
|
int c;
|
|
/* first skip so that we compare same label. */
|
|
if(labs1 > labs2) {
|
|
while(atlabel > labs2) {
|
|
len1 = *d1++;
|
|
d1 += len1;
|
|
atlabel--;
|
|
}
|
|
log_assert(atlabel == labs2);
|
|
} else if(labs1 < labs2) {
|
|
atlabel = labs2;
|
|
while(atlabel > labs1) {
|
|
len2 = *d2++;
|
|
d2 += len2;
|
|
atlabel--;
|
|
}
|
|
log_assert(atlabel == labs1);
|
|
}
|
|
lastmlabs = atlabel+1;
|
|
/* now at same label in d1 and d2, atlabel */
|
|
/* www.example.com. */
|
|
/* 4 3 2 1 atlabel number */
|
|
/* repeat until at root label (which is always the same) */
|
|
while(atlabel > 1) {
|
|
len1 = *d1++;
|
|
len2 = *d2++;
|
|
|
|
if((c=memcanoncmp(d1, len1, d2, len2)) != 0) {
|
|
if(c<0)
|
|
lastdiff = -1;
|
|
else lastdiff = 1;
|
|
lastmlabs = atlabel;
|
|
}
|
|
|
|
d1 += len1;
|
|
d2 += len2;
|
|
atlabel--;
|
|
}
|
|
/* last difference atlabel number, so number of labels matching,
|
|
* at the right side, is one less. */
|
|
*mlabs = lastmlabs-1;
|
|
if(lastdiff == 0) {
|
|
/* all labels compared were equal, check if one has more
|
|
* labels, so that example.com. > com. */
|
|
if(labs1 > labs2)
|
|
return 1;
|
|
else if(labs1 < labs2)
|
|
return -1;
|
|
}
|
|
return lastdiff;
|
|
}
|
|
|
|
int
|
|
dname_canonical_compare(uint8_t* d1, uint8_t* d2)
|
|
{
|
|
int labs1, labs2, m;
|
|
labs1 = dname_count_labels(d1);
|
|
labs2 = dname_count_labels(d2);
|
|
return dname_canon_lab_cmp(d1, labs1, d2, labs2, &m);
|
|
}
|
|
|
|
uint8_t* dname_get_shared_topdomain(uint8_t* d1, uint8_t* d2)
|
|
{
|
|
int labs1, labs2, m;
|
|
size_t len = LDNS_MAX_DOMAINLEN;
|
|
labs1 = dname_count_labels(d1);
|
|
labs2 = dname_count_labels(d2);
|
|
(void)dname_lab_cmp(d1, labs1, d2, labs2, &m);
|
|
dname_remove_labels(&d1, &len, labs1-m);
|
|
return d1;
|
|
}
|