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DNS resolver rewritten, moved to proto/dns.c

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This commit is contained in:
Michael Brown
2005-04-30 14:50:33 +00:00
parent d817e60d21
commit 78cdb1da8b
4 changed files with 414 additions and 477 deletions
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81
src/include/dns.h Normal file
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@@ -0,0 +1,81 @@
#ifndef DNS_RESOLVER_H
#define DNS_RESOLVER_H
#include "stdint.h"
#include "nic.h"
#include "in.h"
/*
* Constants
*
*/
#define DNS_TYPE_A 1
#define DNS_TYPE_CNAME 5
#define DNS_TYPE_ANY 255
#define DNS_CLASS_IN 1
#define DNS_CLASS_CS 2
#define DNS_CLASS_CH 3
#define DNS_CLASS_HS 4
#define DNS_FLAG_QUERY ( 0x00 << 15 )
#define DNS_FLAG_RESPONSE ( 0x01 << 15 )
#define DNS_FLAG_QR(flags) ( (flags) & ( 0x01 << 15 ) )
#define DNS_FLAG_OPCODE_QUERY ( 0x00 << 11 )
#define DNS_FLAG_OPCODE_IQUERY ( 0x01 << 11 )
#define DNS_FLAG_OPCODE_STATUS ( 0x02 << 11 )
#define DNS_FLAG_OPCODE(flags) ( (flags) & ( 0x0f << 11 ) )
#define DNS_FLAG_RD ( 0x01 << 8 )
#define DNS_FLAG_RA ( 0x01 << 7 )
#define DNS_FLAG_RCODE_OK ( 0x00 << 0 )
#define DNS_FLAG_RCODE_NX ( 0x03 << 0 )
#define DNS_FLAG_RCODE(flags) ( (flags) & ( 0x0f << 0 ) )
#define DNS_UDP_PORT 53
#define DNS_MAX_RETRIES 3
#define DNS_MAX_CNAME_RECURSION 0x30
/*
* DNS protocol structures
*
*/
struct dns_header {
uint16_t id;
uint16_t flags;
uint16_t qdcount;
uint16_t ancount;
uint16_t nscount;
uint16_t arcount;
} __attribute__ (( packed ));
struct dns_query_info {
uint16_t qtype;
uint16_t qclass;
} __attribute__ (( packed ));
struct dns_query {
struct iphdr ip;
struct udphdr udp;
struct dns_header dns;
char payload[ 256 + sizeof ( struct dns_query_info ) ];
} __attribute__ (( packed ));
struct dns_rr_info {
uint16_t type;
uint16_t class;
uint16_t ttl;
uint16_t rdlength;
} __attribute__ (( packed ));
struct dns_rr_info_a {
struct dns_rr_info;
struct in_addr in_addr;
} __attribute__ (( packed ));
struct dns_rr_info_cname {
struct dns_rr_info;
char cname[0];
};
#endif /* DNS_RESOLVER_H */

58
src/include/dns_resolver.h
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@@ -1,58 +0,0 @@
// dns_resolver.h - #define statements for the DNS resolver
// We only need A and CNAME queries (later possibly AAAA/A6?)
#define QUERYTYPE_A 1
#define QUERYTYPE_CNAME 5
// We only query with INTERNET class (not CHAOS or whatever)
#define QUERYCLASS_INET 1
// Our first query will have the identifier <1> (arbitrary -
// remember however that (256 - QUERYIDENTIFIER)/2 > MAX_CNAME_RECURSION !!!
#define QUERYIDENTIFIER 1
// Query flags are standard values here
#define QUERYFLAGS 0x0100
#define QUERYFLAGS_MASK 0xf8
#define QUERYFLAGS_WANT 0x80
// Indices inside the byte array that holds DNS queries/answers
#define QINDEX_ID 0
#define QINDEX_FLAGS 2
#define QINDEX_NUMQUEST 4
#define QINDEX_NUMANSW 6
#define QINDEX_NUMAUTH 8
#define QINDEX_NUMADDIT 10
#define QINDEX_QUESTION 12
#define QINDEX_QTYPE 14
#define QINDEX_QCLASS 16
#define QINDEX_STORE_A 256
// Constant UDP port number for DNS traffic
#define UDP_PORT_DNS 53
// Return values that the package parser may give
// This packet was not for us (broadcast or whatever)
#define RET_PACK_GARBAG 0
// Retrieved an address - query finishes
#define RET_GOT_ADDR 1
// No A record for that hostname - try running a CNAME query
#define RET_RUN_CNAME_Q 2
// The CNAME query returned a valid hostname - run A query on that
#define RET_RUN_NEXT_A 3
// The CNAME query failed - stop resolving
#define RET_CNAME_FAIL 4
// We have a reliable input that claims that the hostname does not exist
#define RET_NOSUCHNAME 5
// The name server response is somehow bogus/can not be parsed -> Abort
#define RET_DNSERROR 6
// Return values that the query engine may give
// DNS query succeeded, IP address delivered
#define RET_DNS_OK 0
// DNS query failed
#define RET_DNS_FAIL 1
// Error codes the DNS server can send to us
#define ERR_NOSUCHNAME 3