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minimr.c
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minimr.c
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/**
* minimr - mini mDNS Responder (framework)
*
* https://github.com/tschiemer/minimr
*
* MIT License
*
* Copyright (c) 2020 Philip Tschiemer, filou.se
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "minimr.h"
const uint8_t * minimr_dns_type_tostr(uint16_t type)
{
switch (type) {
case MINIMR_DNS_TYPE_ANY: return (uint8_t*)"ANY";
case MINIMR_DNS_TYPE_A: return (uint8_t*)"A";
case MINIMR_DNS_TYPE_AAAA: return (uint8_t*)"AAAA";
case MINIMR_DNS_TYPE_SRV: return (uint8_t*)"SRV";
case MINIMR_DNS_TYPE_TXT: return (uint8_t*)"TXT";
case MINIMR_DNS_TYPE_PTR: return (uint8_t*)"PTR";
}
return (uint8_t*)"?";
}
const uint8_t * minimr_dns_class_tostr(uint16_t glass)
{
switch (glass) {
case MINIMR_DNS_CLASS_ANY: return (uint8_t*)"ANY";
case MINIMR_DNS_CLASS_IN: return (uint8_t*)"IN";
}
return (uint8_t*)"?";
}
#define _seq1_(lhs, rhs) ( lhs[0] == rhs[0] )
#define _seq2_(lhs, rhs) ( lhs[0] == rhs[0] && lhs[1] == rhs[1] )
#define _seq3_(lhs, rhs) ( lhs[0] == rhs[0] && lhs[1] == rhs[1] && lhs[2] == rhs[2] )
#define _seq4_(lhs, rhs) ( lhs[0] == rhs[0] && lhs[1] == rhs[1] && lhs[2] == rhs[2] && lhs[3] == rhs[4])
uint16_t minimr_dns_type_fromstr(uint8_t * typestr)
{
// in decreasing order of length
if (_seq4_(typestr, "AAAA")) return MINIMR_DNS_TYPE_AAAA;
if (_seq3_(typestr, "ANY")) return MINIMR_DNS_TYPE_ANY;
if (_seq3_(typestr, "SRV")) return MINIMR_DNS_TYPE_SRV;
if (_seq3_(typestr, "TXT")) return MINIMR_DNS_TYPE_TXT;
if (_seq3_(typestr, "PTR")) return MINIMR_DNS_TYPE_PTR;
if (_seq1_(typestr, "A")) return MINIMR_DNS_TYPE_A;
MINIMR_DEBUGF("type not recognized! %s\n", typestr);
return 0;
}
uint16_t minimr_dns_class_fromstr(uint8_t * classstr)
{
// in decreasing order of length
if (_seq3_(classstr, "ANY")) return MINIMR_DNS_CLASS_ANY;
if (_seq2_(classstr, "IN")) return MINIMR_DNS_CLASS_IN;
MINIMR_DEBUGF("class not recognized! %s\n", classstr);
return 0;
}
#undef _seq1_
#undef _seq2_
#undef _seq3_
#undef _seq4_
void minimr_dns_hdr_read(struct minimr_dns_hdr *hdr, uint8_t *src) {
MINIMR_DNS_HDR_READ(src, hdr->transaction_id, hdr->flags[0], hdr->flags[1], hdr->nqueries, hdr->nanswers, hdr->nauthrr, hdr->nextrarr)
MINIMR_DEBUGF("hdr\n id %04x flag %02x%02x nq %04x nrr %04x narr %04x nexrr %04x\n", hdr->transaction_id, hdr->flags[0], hdr->flags[1], hdr->nqueries, hdr->nanswers, hdr->nauthrr, hdr->nextrarr);
}
void minimr_dns_hdr_write(uint8_t *dst, struct minimr_dns_hdr *hdr) {
MINIMR_DNS_HDR_WRITE(dst, hdr->transaction_id, hdr->flags[0], hdr->flags[1], hdr->nqueries, hdr->nanswers, hdr->nauthrr, hdr->nextrarr)
MINIMR_DEBUGF("hdr\n id %04x flag %02x%02x nq %04x nrr %04x narr %04x nexrr %04x\n", hdr->transaction_id, hdr->flags[0], hdr->flags[1], hdr->nqueries, hdr->nanswers, hdr->nauthrr, hdr->nextrarr);
}
uint8_t minimr_extract_query_stat(struct minimr_query_stat * stat, uint8_t * msg, uint16_t * pos, uint16_t msglen)
{
uint16_t p = *pos;
// minlen = QNAME(2)[= <pointer>] QTYPE(2) UNICAST/QCLASS(2)
if (p + 5 >= msglen){
// MINIMR_DEBUGF("0 p %d msglen %d\n", p, msglen);
return MINIMR_NOT_OK;
}
for(; p < msglen && msg[p] != '\0'; p++){
// just looking for the end of rrname
// note: it's not checked wether the rrname is correctly formatted
if ( (msg[p] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME){
p ++;
// MINIMR_DEBUGF("is jump\n");
break;
}
// MINIMR_DEBUGF("p + %d\n", msg[p]);
p += msg[p];
}
// simple sanity check
// did not go beyond msg
// read at least 1 bytes?
if (p >= msglen || p == *pos ){
// MINIMR_DEBUGF("1 *pos %d p %d msglen %d\n", *pos, p, msglen);
return MINIMR_NOT_OK;
}
// stat->name_length = p - *pos;
// move past last name byte (either NUL or second byte of pointer offset
p++;
stat->name_offset = *pos;
stat->type = msg[p++] << 8;
stat->type |= msg[p++];
stat->unicast_class = msg[p++] << 8;
stat->unicast_class |= msg[p++];
*pos = p;
// MINIMR_DEBUGF("qstat\n type %d unicast %d class %d name_offset %d\n", stat->type, (stat->unicast_class & MINIMR_DNS_QUNICAST) == MINIMR_DNS_QUNICAST, stat->unicast_class & MINIMR_DNS_QCLASS, stat->name_offset);
return MINIMR_OK;
}
uint8_t minimr_extract_rr_stat(struct minimr_rr_stat * stat, uint8_t * msg, uint16_t *pos, uint16_t msglen)
{
uint16_t p = *pos;
// minlen = QNAME(2) RRTYPE(2) CACHE/RRCLASS(2) TTL(4) RDLENGTH(2) + RDLENGTH
if (p + 11 >= msglen){
return MINIMR_NOT_OK;
}
stat->name_offset = p;
for(; p < msglen && msg[p] != '\0'; p++){
// just looking for the end of rrname
// note: it's not checked wether the rrname is correctly formatted
if ( (msg[p] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME){
p ++;
// MINIMR_DEBUGF("is jump\n");
break;
}
// MINIMR_DEBUGF("p + %d\n", msg[p]);
p += msg[p];
}
// simple sanity check
// did not go beyond msg
// read at least 1 bytes?
if (p >= msglen || p == *pos ){
return MINIMR_NOT_OK;
}
// minlen = RRTYPE(2) CACHE/RRCLASS(2) TTL(4) RDLENGTH(2) + RDLENGTH
if (p + 10 >= msglen){
return MINIMR_NOT_OK;
}
// move past last name byte (either NUL or second byte of pointer offset
p++;
stat->type = msg[p++] << 8;
stat->type |= msg[p++];
stat->cache_class = msg[p++] << 8;
stat->cache_class |= msg[p++];
stat->ttl = msg[p++] << 24;
stat->ttl |= msg[p++] << 16;
stat->ttl |= msg[p++] << 8;
stat->ttl |= msg[p++];
stat->dlength = msg[p++] << 8;
stat->dlength |= msg[p++];
if (p + stat->dlength > msglen){
return MINIMR_NOT_OK;
}
stat->data_offset = p;
*pos = p + stat->dlength;
return MINIMR_OK;
}
int8_t minimr_dns_rr_lexcmp(uint16_t lhsclass, uint16_t lhstype, uint8_t * lhsrdata, uint16_t lhsrdatalen,
uint16_t rhsclass, uint16_t rhstype, uint8_t * rhsrdata, uint16_t rhsrdatalen)
{
if ( (lhsclass & MINIMR_DNS_QCLASS) < (rhsclass & MINIMR_DNS_QCLASS)) return -1;
if ( (lhsclass & MINIMR_DNS_QCLASS) > (rhsclass & MINIMR_DNS_QCLASS)) return 1;
if ( lhstype < rhstype) return -1;
if ( lhstype > rhstype ) return 1;
uint16_t len = lhsrdatalen < rhsrdatalen ? lhsrdatalen : rhsrdatalen;
uint16_t i = 0;
for (; i < len; i++){
if (lhsrdata[i] < rhsrdata[i]) return -1;
if (lhsrdata[i] > rhsrdata[i]) return 1;
}
//
if (lhsrdatalen < rhsrdatalen) return -1;
if (lhsrdatalen > rhsrdatalen) return 1;
return 0;
}
void minimr_field_normalize(uint8_t * field, uint16_t * length, uint8_t marker)
{
MINIMR_ASSERT(field != NULL);
// if first byte does not match marker, we assume the field has already been normalized
// note: this could the source of an error where the field to be normalized in fact was just wrongly formatted..
if (field[0] != marker){
MINIMR_DEBUGF("WARNING first byte of field to be normalized is not marker '%c' - assumed to be normalized alread\n", marker);
return;
}
uint16_t i = 0;
while(field[i] != '\0'){
MINIMR_ASSERT(field[i] == marker);
uint16_t l = 1;
for(; field[i+l] != '\0' && field[i+l] != marker; l++){
// just looking for boundary
}
MINIMR_ASSERT(l > 0);
field[i] = l - 1;
i += l;
}
if (length != NULL){
*length = i + 1;
}
}
void minimr_field_denormalize(uint8_t * field, uint16_t length, uint8_t marker)
{
MINIMR_ASSERT(field != NULL);
uint8_t seglen;
for(uint16_t pos = 0; pos < length; pos += seglen + 1){
seglen = field[pos];
field[pos] = marker;
}
}
//uint8_t minimr_dns_name_len(uint16_t namepos, uint8_t * msg, uint16_t msglen, uint8_t * namelen, uint8_t * bytelen)
//{
// return MINIMR_OK;
//}
int32_t minimr_name_cmp(uint8_t * uncompressed_name, uint16_t namepos, uint8_t * msg, uint16_t msglen)
{
MINIMR_ASSERT(uncompressed_name != NULL);
MINIMR_ASSERT(msg != NULL);
MINIMR_ASSERT(msglen > 0);
MINIMR_ASSERT(namepos < msglen);
uint16_t len = 0;
uint8_t njumps = 0;
while (uncompressed_name[len] != '\0' && namepos < msglen && msg[namepos] != '\0'){
// is name compressed? jump
if ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME){
uint16_t offset;
// is pointer to pointer?????
do {
// is offset address in msg?
if (namepos+1 >= msglen){
return -1;
}
offset = ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME_OFFSET) << 8) | msg[namepos+1];
njumps++;
// MINIMR_DEBUGF("jumping (%d) to %d\n", njumps, offset);
// evil (or faulty) messages can loop
if (njumps > MINIMR_COMPRESSION_MAX_JUMPS){
return -1;
}
// actually make jump
namepos = offset;
} while ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME);
// repeat
continue;
}
uint8_t seglen = uncompressed_name[len];
// MINIMR_DEBUGF("2 namepos %d seglen %d\n", namepos, seglen);
for(uint8_t i = 0; i <= seglen && namepos < msglen; i++){
uint8_t lhs = uncompressed_name[len++];
uint8_t rhs = msg[namepos++];
#define LOWERCASE(c) ( ('A' <= (c) && (c) <= 'Z') ? ((c) - 'A' + 'a' ) : (c) )
lhs = LOWERCASE(lhs);
rhs = LOWERCASE(rhs);
#undef LOWERCASE
if (lhs < rhs) return -1;
if (lhs > rhs) return 1;
}
}
if (namepos >= msglen){
return 1;
}
// if both are equal, both are NUL
if (uncompressed_name[len] == msg[namepos]) return 0;
if (uncompressed_name[len] == '\0') return -1;
return 1;
}
int32_t minimr_name_uncompress(uint8_t * uncompressed_name, uint16_t maxlen, uint16_t namepos, uint8_t * msg, uint8_t msglen)
{
MINIMR_ASSERT(uncompressed_name != NULL);
MINIMR_ASSERT(maxlen > 0);
MINIMR_ASSERT(msg != NULL);
MINIMR_ASSERT(msglen > 0);
MINIMR_ASSERT(namepos < msglen);
uint16_t len = 0;
uint8_t njumps = 0;
while (len < maxlen && namepos < msglen && msg[namepos] != '\0'){
// is name compressed? jump
if ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME){
uint16_t offset;
// is pointer to pointer?????
do {
// MINIMR_DEBUGF("is jump\n");
// is offset address in msg?
if (namepos+1 >= msglen){
return -1;
}
offset = ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME_OFFSET) << 8) | msg[namepos+1];
njumps++;
// MINIMR_DEBUGF("jumping (%d) to %d\n", njumps, offset);
// evil (or faulty) messages can loop
if (njumps > MINIMR_COMPRESSION_MAX_JUMPS){
return -1;
}
// actually make jump
namepos = offset;
} while ((msg[namepos] & MINIMR_DNS_COMPRESSED_NAME) == MINIMR_DNS_COMPRESSED_NAME);
// repeat
continue;
}
uint8_t seglen = msg[namepos];
if (namepos + seglen >= msglen){
return -1;
}
// seglen
uncompressed_name[len++] = msg[namepos++];
for (uint8_t i = 0; i < seglen; i++){
uncompressed_name[len++] = msg[namepos++];
}
}
if (len >= maxlen || namepos >= msglen){
return -1;
}
uncompressed_name[len] = '\0';
return len;
}
int32_t minimr_parse_msg(
uint8_t *msg, uint16_t msglen,
minimr_msgtype msgtype,
minimr_query_handler qhandler, struct minimr_filter * qfilters, uint16_t nqfilters,
minimr_rr_handler rrhandler, struct minimr_filter * rrfilters, uint16_t nrrfilters,
void * user_data
)
{
MINIMR_ASSERT(msg != NULL);
MINIMR_ASSERT(nqfilters == 0 || qfilters != NULL);
MINIMR_ASSERT(nrrfilters == 0 || rrfilters != NULL);
MINIMR_ASSERT(qhandler != NULL && rrhandler != NULL); // doesn't make any sense not to use any handler at all.
// MINIMR_DEBUGF("\nnew msg %p (len %d)\n", msg, msglen);
//
// MINIMR_DEBUGF("msglen check\n");
// ignore messages that are not long enough to even have a complete header
if (msglen < MINIMR_DNS_HDR_SIZE){
return MINIMR_OK;
}
struct minimr_dns_hdr hdr;
// read header info
minimr_dns_hdr_read(&hdr, msg);
// if asked for specific type but other at hand, abort
if ((msgtype == minimr_msgtype_query && (hdr.flags[0] & MINIMR_DNS_HDR1_QR) == MINIMR_DNS_HDR1_QR_REPLY )
|| (msgtype == minimr_msgtype_response && (hdr.flags[0] & MINIMR_DNS_HDR1_QR) == MINIMR_DNS_HDR1_QR_REPLY )){
return MINIMR_OK;
}
uint16_t pos = MINIMR_DNS_HDR_SIZE;
for(uint16_t iq = 0; iq < hdr.nqueries && pos < msglen; iq++){
struct minimr_query_stat qstat;
uint8_t res = minimr_extract_query_stat(&qstat, msg, &pos, msglen);
// in case of a server fail, pass this along
if (res == MINIMR_DNS_HDR2_RCODE_SERVAIL) {
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
if (res != MINIMR_OK){
// we could respond that it was a faulty query..
return MINIMR_DNS_HDR2_RCODE_FORMERR;
}
if (qhandler == NULL){
continue;
}
uint8_t cont = MINIMR_CONTINUE;
if (nqfilters == 0){
cont = qhandler(&hdr, &qstat, msg, msglen, user_data);
} else {
for (uint16_t i = 0; i < nqfilters; i++){
MINIMR_ASSERT(qfilters[i].name != NULL);
// type match?
if (qfilters[i].type != MINIMR_DNS_TYPE_ANY && qstat.type != MINIMR_DNS_TYPE_ANY && qfilters[i].type != qstat.type){
continue;
}
// class match?
if (qfilters[i].fclass != MINIMR_DNS_CLASS_ANY && (qstat.unicast_class & MINIMR_DNS_QCLASS) != MINIMR_DNS_CLASS_ANY && qfilters[i].fclass != (qstat.unicast_class & MINIMR_DNS_QCLASS) ){
continue;
}
if (minimr_name_cmp(qfilters[i].name, qstat.name_offset, msg, msglen) == 0){
qstat.match_i = i;
// pass to user rr handler
cont = qhandler(&hdr, &qstat, msg, msglen, user_data);
}
}
}
if (cont != MINIMR_CONTINUE){
return MINIMR_OK;
}
}
// msg seems to be faulty, stop processing
if (pos > msglen){
return MINIMR_DNS_HDR2_RCODE_FORMERR;
}
if (pos == msglen){
return MINIMR_OK;
}
// if we're not interested in records, skip further processing
if (rrhandler == NULL){
return MINIMR_OK;
}
MINIMR_DEBUGF("checking %d rr, %d authrr, %d extrarr\n", hdr.nanswers, hdr.nauthrr, hdr.nextrarr);
uint16_t nrr = hdr.nanswers + hdr.nauthrr + hdr.nextrarr;
minimr_rr_section section = minimr_rr_section_answer;
uint16_t section_until = hdr.nanswers;
for(uint16_t ir = 0; ir < nrr && pos < msglen; ir++){
struct minimr_rr_stat rstat;
uint8_t res = minimr_extract_rr_stat(&rstat, msg, &pos, msglen);
// in case of a server fail, pass this along
if (res == MINIMR_DNS_HDR2_RCODE_SERVAIL) {
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
if (res != MINIMR_OK){
// we could respond that it was a faulty query..
return MINIMR_DNS_HDR2_RCODE_FORMERR;
}
if (section == minimr_rr_section_answer && ir >= section_until){
section = minimr_rr_section_authority;
section_until += hdr.nauthrr;
}
if (section == minimr_rr_section_authority && ir >= section_until){
section = minimr_rr_section_extra;
}
uint8_t cont = MINIMR_CONTINUE;
// if any filter records were given, just look for these
if (nrrfilters == 0) {
cont = rrhandler(&hdr, section, &rstat, msg, msglen, user_data);
} else {
for (uint16_t i = 0; i < nrrfilters; i++){
MINIMR_ASSERT(rrfilters[i].name != NULL);
// type match?
if (rrfilters[i].type != MINIMR_DNS_TYPE_ANY && rrfilters[i].type != rstat.type){
continue;
}
// class match?
if (rrfilters[i].fclass != MINIMR_DNS_CLASS_ANY && rrfilters[i].fclass != (rstat.cache_class & MINIMR_DNS_RRCLASS) ){
continue;
}
if (minimr_name_cmp(rrfilters[i].name, rstat.name_offset, msg, msglen) == 0){
rstat.match_i = i;
// pass to user rr handler
cont = rrhandler(&hdr, section, &rstat, msg, msglen, user_data);
}
}
}
if (cont != MINIMR_CONTINUE){
return MINIMR_OK;
}
}
return MINIMR_OK;
}
int32_t minimr_make_msg(
uint16_t tid, uint8_t flag1, uint8_t flag2,
struct minimr_query * queries, uint16_t nqueries,
struct minimr_rr ** answerrr, uint16_t nanswers,
struct minimr_rr ** authrr, uint16_t nauthrr,
struct minimr_rr ** extrarr, uint16_t nextrarr,
uint8_t *outmsg, uint16_t *outmsglen, uint16_t outmsgmaxlen,
void * user_data
)
{
MINIMR_ASSERT(nqueries == 0 || queries != NULL);
MINIMR_ASSERT(nanswers == 0 || answerrr != NULL);
MINIMR_ASSERT(nauthrr == 0 || authrr != NULL);
MINIMR_ASSERT(nextrarr == 0 || extrarr != NULL);
MINIMR_ASSERT(outmsg != NULL);
MINIMR_ASSERT(outmsglen != NULL);
// sanity check config
if (outmsgmaxlen <= MINIMR_DNS_HDR_SIZE){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
uint16_t outlen = MINIMR_DNS_HDR_SIZE;
for (uint16_t i = 0; i < nqueries; i++){
MINIMR_ASSERT(queries[i].name != NULL);
for(uint16_t j = 0; queries[i].name[j] != '\0'; j++){
if (outlen > outmsgmaxlen){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
outmsg[outlen++] = queries[i].name[j];
// MINIMR_DEBUGF("%02x ", queries[i].name[j]);
}
// MINIMR_DEBUGF("\n");
if (outlen + 5 > outmsgmaxlen){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
// name termination
outmsg[outlen++] = '\0';
MINIMR_DNS_Q_WRITE_TYPE( outmsg, outlen, queries[i].type);
MINIMR_DNS_Q_WRITE_CLASS( outmsg, outlen, queries[i].unicast_class );
}
MINIMR_DEBUGF("added %d queries\n", nqueries);
uint16_t final_nanswers = 0; // needed because there might be NULL entries
// add all normal answers RRs
for(uint16_t i = 0; i < nanswers; i++){
if (answerrr[i] == NULL){
continue;
}
uint16_t nrr = 0;
//minimr_rr_fun_handler( minimr_rr_fun_get_rr, struct minimr_rr * rr, uint8_t * outmsg, uint16_t * outlen, uint16_t outmsgmaxlen, uint16_t * nrr, void * user_data)
uint8_t res = answerrr[i]->MINIMR_RR_FUN_GET_RR(answerrr[i], outmsg, &outlen, outmsgmaxlen, &nrr, user_data);
if (res != MINIMR_OK){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
final_nanswers += nrr;
}
MINIMR_DEBUGF("added %d known answer rr\n", nanswers);
uint16_t final_nauthrr = 0;
// add all normal answers RRs
for(uint16_t i = 0; i < nauthrr; i++){
if (authrr[i] == NULL){
continue;
}
uint16_t nrr = 0;
uint8_t res = authrr[i]->MINIMR_RR_FUN_GET_RR(authrr[i], outmsg, &outlen, outmsgmaxlen, &nrr, user_data);
if (res != MINIMR_OK){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
final_nauthrr += nrr;
}
MINIMR_DEBUGF("added %d extra rr\n", nauthrr);
uint16_t final_nextrarr = 0;
// add all normal answers RRs
for(uint16_t i = 0; i < nextrarr; i++){
if (extrarr[i] == NULL){
continue;
}
uint16_t nrr = 0;
uint8_t res = extrarr[i]->MINIMR_RR_FUN_GET_RR(extrarr[i], outmsg, &outlen, outmsgmaxlen, &nrr, user_data);
if (res != MINIMR_OK){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
final_nextrarr += nrr;
}
MINIMR_DEBUGF("added %d extra rr\n", nextrarr);
// prepare outheader and out sanity check
struct minimr_dns_hdr outhdr;
// finalize header
outhdr.transaction_id = tid;
// set QR flag depending on queries given
flag1 = (flag1 & ~MINIMR_DNS_HDR1_QR) | (nqueries ? MINIMR_DNS_HDR1_QR_QUERY : MINIMR_DNS_HDR1_QR_REPLY);
// note: the AA flag is not set by default (because maybe, maybe you don't want to send an authorative answer ;)
outhdr.flags[0] = flag1;
outhdr.flags[1] = flag2;
outhdr.nqueries = nqueries;
outhdr.nanswers = final_nanswers;
outhdr.nauthrr = final_nauthrr;
outhdr.nextrarr = final_nextrarr;
// add header
minimr_dns_hdr_write(outmsg, &outhdr);
*outmsglen = outlen;
return MINIMR_OK;
}
int32_t minimr_probequery_msg(
uint8_t * name1,
uint8_t * name2,
struct minimr_rr ** proposed_rrs, uint16_t nproposed_rrs,
uint8_t *outmsg, uint16_t *outmsglen, uint16_t outmsgmaxlen,
uint8_t request_unicast,
void * user_data
)
{
MINIMR_ASSERT(name1 != NULL);
MINIMR_ASSERT(proposed_rrs != NULL);
MINIMR_ASSERT(nproposed_rrs > 0);
struct minimr_query queries[2];
queries[0].unicast_class = MINIMR_DNS_CLASS_IN | (request_unicast ? MINIMR_DNS_QUNICAST : 0);
queries[0].type = MINIMR_DNS_TYPE_ANY;
queries[0].name = name1;
uint16_t nqueries = 1;
if (name2 != NULL){
queries[1].unicast_class = MINIMR_DNS_CLASS_IN | (request_unicast ? MINIMR_DNS_QUNICAST : 0);
queries[1].type = MINIMR_DNS_TYPE_ANY;
queries[1].name = name2;
nqueries++;
}
return minimr_make_msg(
0, 0, 0, // no special header
queries, nqueries,
NULL, 0, // no answer rrs
proposed_rrs, nproposed_rrs, // proposed records in auth section
NULL, 0, // no extra rrs
outmsg, outmsglen, outmsgmaxlen,
user_data
);
}
int32_t minimr_query_msg(
uint8_t * name1,
uint8_t * name2,
struct minimr_rr ** knownanswer_rrs, uint16_t nknownanswer_rrs,
uint8_t *outmsg, uint16_t *outmsglen, uint16_t outmsgmaxlen,
uint8_t request_unicast,
void * user_data
)
{
MINIMR_ASSERT(name1 != NULL);
MINIMR_ASSERT(nknownanswer_rrs == 0 | knownanswer_rrs != NULL);
struct minimr_query queries[2];
queries[0].type = MINIMR_DNS_TYPE_ANY;
queries[0].unicast_class = MINIMR_DNS_CLASS_IN | (request_unicast ? MINIMR_DNS_QUNICAST : 0);
queries[0].name = name1;
uint16_t nqueries = 1;
if (name2 != NULL){
queries[1].type = MINIMR_DNS_TYPE_ANY;
queries[1].unicast_class = MINIMR_DNS_CLASS_IN | (request_unicast ? MINIMR_DNS_QUNICAST : 0);
queries[1].name = name2;
}
return minimr_make_msg(
0, 0, 0, // no special header
queries, nqueries,
knownanswer_rrs, nknownanswer_rrs,
NULL, 0, // no auth rrs
NULL, 0, // no extra rrs
outmsg, outmsglen, outmsgmaxlen,
user_data
);
}
int32_t minimr_announce_msg(
struct minimr_rr **records, uint16_t nrecords,
uint8_t *outmsg, uint16_t *outmsglen, uint16_t outmsgmaxlen,
void * user_data
)
{
// sanity check config
if (outmsgmaxlen <= MINIMR_DNS_HDR_SIZE){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
uint16_t outlen = MINIMR_DNS_HDR_SIZE;
uint16_t nanswers = 0;
// add all normal answers RRs
for(uint16_t i = 0; i < nrecords; i++){
if (records[i] == NULL){
continue;
}
uint16_t nrr = 0;
//minimr_rr_fun_handler( minimr_rr_fun_announce_get_*, struct minimr_rr * rr, uint8_t * outmsg, uint16_t * outlen, uint16_t outmsgmaxlen, uint16_t * nrr, void * user_data)
uint8_t res = records[i]->MINIMR_RR_FUN_ANNOUNCE_GET_RR( records[i], outmsg, &outlen, outmsgmaxlen, &nrr, user_data);
if (res != MINIMR_OK){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
nanswers += nrr;
}
MINIMR_DEBUGF("added %d answer rr\n", nanswers);
// add all additional RRs
uint16_t nextrarr = 0;
for(uint16_t i = 0; i < nrecords; i++){
// don't check questions that have become irrelevant
if (records[i] == NULL){
continue;
}
uint16_t nrr = 0;
//minimr_rr_fun_handler( minimr_rr_fun_announce_get_*, struct minimr_rr * rr, uint8_t * outmsg, uint16_t * outlen, uint16_t outmsgmaxlen, uint16_t * nrr, void * user_data)
uint8_t res = records[i]->MINIMR_RR_FUN_ANNOUNCE_GET_EXTRA_RRS( records[i], outmsg, &outlen, outmsgmaxlen, &nrr, user_data);
if (res != MINIMR_OK){
return MINIMR_DNS_HDR2_RCODE_SERVAIL;
}
nextrarr += nrr;
}
MINIMR_DEBUGF("added %d extra rr\n", nextrarr);
// prepare outheader and out sanity check
struct minimr_dns_hdr outhdr;
// finalize header
outhdr.transaction_id = 0;
outhdr.flags[0] = MINIMR_DNS_HDR1_QR_REPLY | MINIMR_DNS_HDR1_AA;
outhdr.flags[1] = MINIMR_DNS_HDR2_RCODE_NOERROR;
outhdr.nqueries = 0;
outhdr.nanswers = nanswers;
outhdr.nauthrr = 0;
outhdr.nextrarr = nextrarr;
// add header
minimr_dns_hdr_write(outmsg, &outhdr);
*outmsglen = outlen;
return MINIMR_DNS_HDR2_RCODE_NOERROR;
}
int32_t minimr_terminate_msg(
struct minimr_rr **records, uint16_t nrecords,
uint8_t *outmsg, uint16_t *outmsglen, uint16_t outmsgmaxlen,
void * user_data
)
{
for(uint16_t i = 0; i < nrecords; i++){
if (records[i] == NULL){
continue;
}
records[i]->ttl = 0;
}
return minimr_announce_msg(records, nrecords, outmsg, outmsglen, outmsgmaxlen, user_data);
}
int32_t minimr_query_response_msg(
uint8_t * msg, uint16_t msglen,
struct minimr_query_stat qstats[], uint16_t nqstats,
struct minimr_rr ** records, uint16_t nrecords,
uint8_t *outmsg, uint16_t * outmsglen, uint16_t outmsgmaxlen,
uint8_t *unicast_requested,
void * user_data
)
{
MINIMR_ASSERT(msg != NULL);
MINIMR_ASSERT(qstats != NULL);
MINIMR_ASSERT(nqstats > 0);
MINIMR_ASSERT(records != NULL);
MINIMR_ASSERT(nrecords > 0);
MINIMR_ASSERT(outmsg != NULL);
MINIMR_ASSERT(outmsglen != NULL);
MINIMR_ASSERT(outmsgmaxlen > MINIMR_DNS_HDR_SIZE);
// MINIMR_DEBUGF("\nnew msg %p (len %d)\n", msg, msglen);
// MINIMR_DEBUGF("msglen check\n");
// ignore messages that are not long enough to even have a complete header
if (msglen < MINIMR_DNS_HDR_SIZE){
return MINIMR_IGNORE;
}
struct minimr_dns_hdr hdr;
// read header info
minimr_dns_hdr_read(&hdr, msg);
// MINIMR_DEBUGF("is standard query?\n");
// not a (standard) query? ignore
// or no questions? nothing to do!
if ( (hdr.flags[0] & MINIMR_DNS_HDR1_QR) != MINIMR_DNS_HDR1_QR_QUERY ||
(hdr.flags[0] & MINIMR_DNS_HDR1_OPCODE) != MINIMR_DNS_HDR1_OPCODE_QUERY ||
hdr.nqueries == 0){
return MINIMR_IGNORE;
}