#include <stdint.h> // uint*_t
#include <string.h> // memcpy, strchr
#include <assert.h>
+#include <acess/sys.h> // for _SysSelect
+#include <acess/fd_set.h> // FD_SET
#include <net.h>
#include "include/dns.h"
+#include "include/dns_int.h"
// === PROTOTYPES ===
-size_t DNS_EncodeName(void *buf, const char *dotted_name);
-int DNS_DecodeName(char dotted_name[256], const void *buf, size_t space);
-int DNS_int_ParseRR(const void *buf, 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 size_t put16(void *buf, uint16_t val);
-
+//int DNS_Query(int ServerAType, const void *ServerAddr, const char *name, enum eTypes type, enum eClass class, handle_record_t* handle_record, void *info);
// === 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) ); // Op : Query, Standard, no other flags
- 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
int sock = Net_OpenSocket_UDP(ServerAType, ServerAddr, 53, 0);
if( sock < 0 ) {
// Connection failed
+ _SysDebug("DNS_Query - UDP open failed");
// TODO: Correctly report this failure with a useful error code
return 1;
}
- int rv = _SysWrite(sock, packet, pos);
+ int rv = Net_UDP_SendTo(sock, 53, ServerAType, ServerAddr, pos, packet);
if( rv != pos ) {
+ _SysDebug("DNS_Query - Write failed");
// TODO: Error reporting
_SysClose(sock);
return 1;
}
// - Wait
- int return_len = 0;
- do {
- return_len = _SysRead(sock, packet, sizeof(packet));
- } while( return_len == 0 );
- if( return_len < 0 ) {
- // TODO: Error reporting
- _SysClose(sock);
- return 1;
- }
- _SysClose(sock);
- // - Release
- // > TODO: Lock DNS queries
-
- // For each response in the answer (and additional) sections, call the passed callback
- char rr_name[256];
- 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);
- 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 ++ ) {
- pos += DNS_DecodeName(NULL, packet + pos, return_len - pos);
- pos += 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 - pos, rr_name, &type, &class, &ttl, &rdlength);
- if( rv < 0 ) {
+ int nfd = sock + 1;
+ fd_set fds;
+ FD_ZERO(&fds);
+ FD_SET(sock, &fds);
+ int64_t timeout = 2000; // Give it two seconds, should be long enough
+ rv = _SysSelect(nfd, &fds, NULL, NULL, &timeout, 0);
+ if( rv == 0 ) {
+ // Timeout with no reply, give up
+ _SysDebug("DNS_Query - Timeout");
+ _SysClose(sock);
return 1;
}
- pos += rv;
-
- handle_record(info, rr_name, type, class, ttl, rdlength, packet + pos);
- }
- // 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 - pos, rr_name, NULL, NULL, NULL, &rdlength);
if( rv < 0 ) {
+ // Oops, select failed
+ _SysDebug("DNS_Query - Select failure");
+ _SysClose(sock);
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 - pos, rr_name, &type, &class, &ttl, &rdlength);
- if( rv < 0 ) {
- return 1;
- }
- pos += rv;
-
- handle_record(info, rr_name, type, class, ttl, rdlength, packet + pos);
- }
-
- 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 space)
-{
- int consumed = 0;
- int out_pos = 0;
- const uint8_t *buf8 = buf;
- while( *buf8 && space > 0 )
- {
- if( consumed + 1 > space ) return -1;
- uint8_t seg_len = *buf8;
- buf8 ++;
- consumed ++;
- // Protocol violation (overflowed end of buffer)
- if( consumed + seg_len > space )
- return -1;
- // Protocol violation (segment too long)
- if( seg_len >= 64 )
- return -1;
- // Protocol violation (name was too long)
- if( out_pos + seg_len + 1 > sizeof(dotted_name)-1 )
- return -1;
-
- // Read segment
- memcpy(dotted_name + out_pos, buf8, seg_len);
- buf8 += seg_len;
- consumed += seg_len;
-
- // Place '.'
- dotted_name[out_pos+seg_len+1] = '.';
- // Increment output counter
- out_pos += seg_len + 1;
+ int return_len = Net_UDP_RecvFrom(sock, NULL, NULL, NULL, sizeof(packet), packet);
+ if( return_len <= 0 ) {
+ // TODO: Error reporting
+ _SysDebug("DNS_Query - Read failure");
+ _SysClose(sock);
+ return 1;
}
+ _SysClose(sock);
+ // - Release
+ // > TODO: Lock DNS queries
- dotted_name[out_pos] = '\0';
- return consumed;
-}
-
-// Parse a Resource Record
-int DNS_int_ParseRR(const void *buf, 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, buf8, space);
- if(rv < 0) return -1;
-
- buf8 += rv, consumed += rv;
-
- if( type_p )
- *type_p = get16(buf8);
- buf8 += 2, consumed += 2;
-
- if( class_p )
- *class_p = get16(buf8);
- buf8 += 2, consumed += 2;
-
- return consumed;
-}
-
-static uint16_t get16(const void *buf) {
- const uint8_t* buf8 = buf;
- uint16_t rv = 0;
- rv |= buf8[0];
- rv |= (uint16_t)buf8[1] << 8;
- return rv;
-}
-static size_t put16(void *buf, uint16_t val) {
- uint8_t* buf8 = buf;
- buf8[0] = val & 0xFF;
- buf8[1] = val >> 8;
- return 2;
+ // For each response in the answer (and additional) sections, call the passed callback
+ return DNS_int_ParseResponse(packet, return_len, info, handle_record);
}
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