#include <acess/fd_set.h> // FD_SET
#include <net.h>
#include "include/dns.h"
+#include "include/dns_int.h"
// === PROTOTYPES ===
//int DNS_Query(int ServerAType, const void *ServerAddr, const char *name, enum eTypes type, enum eClass class, handle_record_t* handle_record, void *info);
-int DNS_int_ParseResponse(const void* packet, size_t return_len, void *info, handle_record_t* handle_record_t);
-size_t DNS_EncodeName(void *buf, const char *dotted_name);
-int DNS_DecodeName(char dotted_name[256], const void *buf, size_t ofs, size_t space);
-int DNS_int_ParseRR(const void *buf, size_t ofs, size_t space, char* name_p, enum eTypes* type_p, enum eClass* class_p, uint32_t* ttl_p, size_t* rdlength_p);
-
-static uint16_t get16(const void *buf);
-static uint32_t get32(const void *buf);
-static size_t put16(void *buf, uint16_t val);
-
// === CODE ===
int DNS_Query(int ServerAType, const void *ServerAddr, const char *name, enum eTypes type, enum eClass class, handle_record_t* handle_record, void *info)
{
- int namelen = DNS_EncodeName(NULL, name);
- assert(namelen < 256);
- size_t pos = 0;
- char packet[ 512 ];
- assert( (6*2) + (namelen + 2*2) < 512 );
- // - Header
- pos += put16(packet + pos, 0xAC00); // Identifier (arbitary)
- pos += put16(packet + pos, (0 << 0) | (0 << 1) | (1 << 8) ); // Op : Query, Standard, Recursion
- pos += put16(packet + pos, 1); // QDCount
- pos += put16(packet + pos, 0); // ANCount
- pos += put16(packet + pos, 0); // NSCount
- pos += put16(packet + pos, 0); // ARCount
- // - Question
- pos += DNS_EncodeName(packet + pos, name);
- pos += put16(packet + pos, type); // QType
- pos += put16(packet + pos, class); // QClass
-
- assert(pos <= sizeof(packet));
+ char packet[512];
+ size_t packlen = DNS_int_EncodeQuery(packet, sizeof(packet), name, type, class);
// Send and wait for reply
// - Lock
return DNS_int_ParseResponse(packet, return_len, info, handle_record);
}
-int DNS_int_ParseResponse(const void* buf, size_t return_len, void *info, handle_record_t* handle_record)
-{
- const uint8_t* packet = buf;
- char rr_name[256];
- unsigned int id = get16(packet + 0);
- if( id != 0xAC00 ) {
- _SysDebug("DNS_Query - Packet ID mismatch");
- return 2;
- }
- unsigned int flags = get16(packet + 2);
- unsigned int qd_count = get16(packet + 4);
- unsigned int an_count = get16(packet + 6);
- unsigned int ns_count = get16(packet + 8);
- unsigned int ar_count = get16(packet + 10);
- size_t pos = 6*2;
- // TODO: Can I safely assert / fail if qd_count is non-zero?
- // - Questions, ignored
- for( unsigned int i = 0; i < qd_count; i ++ ) {
- int rv = DNS_DecodeName(rr_name, packet, pos, return_len);
- if( rv < 0 ) {
- _SysDebug("DNS_Query - Parse error in QD");
- return 1;
- }
- pos += rv + 2*2;
- }
- // - Answers, pass on to handler
- for( unsigned int i = 0; i < an_count; i ++ )
- {
- enum eTypes type;
- enum eClass class;
- uint32_t ttl;
- size_t rdlength;
- int rv = DNS_int_ParseRR(packet, pos, return_len, rr_name, &type, &class, &ttl, &rdlength);
- if( rv < 0 ) {
- _SysDebug("DNS_Query - Parse error in AN");
- return 1;
- }
- pos += rv;
-
- handle_record(info, rr_name, type, class, ttl, rdlength, packet + pos - rdlength);
- }
- // Authority Records (should all be NS records)
- for( unsigned int i = 0; i < ns_count; i ++ )
- {
- size_t rdlength;
- int rv = DNS_int_ParseRR(packet, pos, return_len, rr_name, NULL, NULL, NULL, &rdlength);
- if( rv < 0 ) {
- _SysDebug("DNS_Query - Parse error in NS");
- return 1;
- }
- pos += rv;
- }
- // - Additional records, pass to handler
- for( unsigned int i = 0; i < ar_count; i ++ )
- {
- enum eTypes type;
- enum eClass class;
- uint32_t ttl;
- size_t rdlength;
- int rv = DNS_int_ParseRR(packet, pos, return_len, rr_name, &type, &class, &ttl, &rdlength);
- if( rv < 0 ) {
- _SysDebug("DNS_Query - Parse error in AR");
- return 1;
- }
- pos += rv;
-
- handle_record(info, rr_name, type, class, ttl, rdlength, packet + pos - rdlength);
- }
-
- return 0;
-}
-
-/// Encode a dotted name as a DNS name
-size_t DNS_EncodeName(void *buf, const char *dotted_name)
-{
- size_t ret = 0;
- const char *str = dotted_name;
- uint8_t *buf8 = buf;
- while( *str )
- {
- const char *next = strchr(str, '.');
- size_t seg_len = (next ? next - str : strlen(str));
- if( seg_len > 63 ) {
- // Oops, too long (truncate)
- seg_len = 63;
- }
- if( seg_len == 0 && next != NULL ) {
- // '..' encountered, invalid (skip)
- str = next+1;
- continue ;
- }
-
- if( buf8 )
- {
- buf8[ret] = seg_len;
- memcpy(buf8+ret+1, str, seg_len);
- }
- ret += 1 + seg_len;
-
- if( next == NULL ) {
- // No trailing '.', assume it's there? Yes, need to be NUL terminated
- if(buf8) buf8[ret] = 0;
- ret ++;
- break;
- }
- else {
- str = next + 1;
- }
- }
- return ret;
-}
-
-// Decode a name (including trailing . for root)
-int DNS_DecodeName(char dotted_name[256], const void *buf, size_t ofs, size_t space)
-{
- int consumed = 0;
- int out_pos = 0;
- const uint8_t *buf8 = (const uint8_t*)buf + ofs;
- for( ;; )
- {
- if( ofs + consumed + 1 > space ) {
- _SysDebug("DNS_DecodeName - Len byte OOR space=%i", space);
- return -1;
- }
- uint8_t seg_len = *buf8;
- buf8 ++;
- consumed ++;
- // Done
- if( seg_len == 0 )
- break;
- if( (seg_len & 0xC0) == 0xC0 )
- {
- // Backreference, the rest of the name is a backref
- char tmp[256];
- int ref_ofs = get16(buf8 - 1) & 0x3FFF;
- consumed += 1, buf8 += 1; // Only one, previous inc still applies
- _SysDebug("DNS_DecodeName - Nested at %i", ref_ofs);
- if( DNS_DecodeName(tmp, buf, ref_ofs, space) < 0 )
- return -1;
- memcpy(dotted_name+out_pos, tmp, strlen(tmp));
- out_pos += strlen(tmp);
- break;
- }
- // Protocol violation (segment too long)
- if( seg_len >= 64 ) {
- _SysDebug("DNS_DecodeName - Seg too long %i", seg_len);
- return -1;
- }
- // Protocol violation (overflowed end of buffer)
- if( ofs + consumed + seg_len > space ) {
- _SysDebug("DNS_DecodeName - Seg OOR %i+%i>%i", consumed, seg_len, space);
- return -1;
- }
- // Protocol violation (name was too long)
- if( out_pos + seg_len + 1 > 255 ) {
- _SysDebug("DNS_DecodeName - Dotted name too long %i+%i+1 > %i",
- out_pos, seg_len, 255);
- return -1;
- }
-
- _SysDebug("DNS_DecodeName : Seg %i '%.*s'", seg_len, seg_len, buf8);
-
- // Read segment
- memcpy(dotted_name + out_pos, buf8, seg_len);
- buf8 += seg_len;
- consumed += seg_len;
- out_pos += seg_len;
-
- // Place '.'
- dotted_name[out_pos] = '.';
- out_pos ++;
- }
- dotted_name[out_pos] = '\0';
- _SysDebug("DNS_DecodeName - '%s', consumed = %i", dotted_name, consumed);
- return consumed;
-}
-
-// Parse a Resource Record
-int DNS_int_ParseRR(const void *buf, size_t ofs, size_t space, char* name_p, enum eTypes* type_p, enum eClass* class_p, uint32_t* ttl_p, size_t* rdlength_p)
-{
- const uint8_t *buf8 = buf;
- size_t consumed = 0;
-
- // 1. Name
- int rv = DNS_DecodeName(name_p, buf, ofs, space);
- if(rv < 0) return -1;
-
- ofs += rv, consumed += rv;
-
- if( type_p )
- *type_p = get16(buf8 + ofs);
- ofs += 2, consumed += 2;
-
- if( class_p )
- *class_p = get16(buf8 + ofs);
- ofs += 2, consumed += 2;
-
- if( ttl_p )
- *ttl_p = get32(buf + ofs);
- ofs += 4, consumed += 4;
-
- size_t rdlength = get16(buf + ofs);
- if( rdlength_p )
- *rdlength_p = rdlength;
- ofs += 2, consumed += 2;
-
- _SysDebug("DNS_int_ParseRR - name='%s', rdlength=%i", name_p, rdlength);
-
- return consumed + rdlength;
-}
-
-static uint16_t get16(const void *buf) {
- const uint8_t* buf8 = buf;
- uint16_t rv = 0;
- rv |= (uint16_t)buf8[0] << 8;
- rv |= (uint16_t)buf8[1] << 0;
- return rv;
-}
-static uint32_t get32(const void *buf) {
- const uint8_t* buf8 = buf;
- uint32_t rv = 0;
- rv |= (uint32_t)buf8[0] << 24;
- rv |= (uint32_t)buf8[1] << 16;
- rv |= (uint32_t)buf8[2] << 8;
- rv |= (uint32_t)buf8[3] << 0;
- return rv;
-}
-static size_t put16(void *buf, uint16_t val) {
- uint8_t* buf8 = buf;
- buf8[0] = val >> 8;
- buf8[1] = val & 0xFF;
- return 2;
-}
-
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