| 1 | // dns_resolver.h - #define statements for the DNS resolver
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| 2 |
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| 3 | // We only need A and CNAME queries (later possibly AAAA/A6?)
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| 4 | #define QUERYTYPE_A 1
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| 5 | #define QUERYTYPE_CNAME 5
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| 6 |
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| 7 | // We only query with INTERNET class (not CHAOS or whatever)
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| 8 | #define QUERYCLASS_INET 1
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| 9 |
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| 10 | // Our first query will have the identifier <1> (arbitrary -
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| 11 | // remember however that (256 - QUERYIDENTIFIER)/2 > MAX_CNAME_RECURSION !!!
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| 12 | #define QUERYIDENTIFIER 1
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| 13 |
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| 14 | // Query flags are standard values here
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| 15 | #define QUERYFLAGS 0x0100
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| 16 | #define QUERYFLAGS_MASK 0xf8
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| 17 | #define QUERYFLAGS_WANT 0x80
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| 18 |
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| 19 | // Indices inside the byte array that holds DNS queries/answers
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| 20 | #define QINDEX_ID 0
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| 21 | #define QINDEX_FLAGS 2
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| 22 | #define QINDEX_NUMQUEST 4
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| 23 | #define QINDEX_NUMANSW 6
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| 24 | #define QINDEX_NUMAUTH 8
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| 25 | #define QINDEX_NUMADDIT 10
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| 26 | #define QINDEX_QUESTION 12
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| 27 | #define QINDEX_QTYPE 14
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| 28 | #define QINDEX_QCLASS 16
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| 29 | #define QINDEX_STORE_A 256
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| 30 |
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| 31 | // Constant UDP port number for DNS traffic
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| 32 | #define UDP_PORT_DNS 53
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| 33 |
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| 34 | // Return values that the package parser may give
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| 35 | // This packet was not for us (broadcast or whatever)
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| 36 | #define RET_PACK_GARBAG 0
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| 37 | // Retrieved an address - query finishes
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| 38 | #define RET_GOT_ADDR 1
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| 39 | // No A record for that hostname - try running a CNAME query
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| 40 | #define RET_RUN_CNAME_Q 2
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| 41 | // The CNAME query returned a valid hostname - run A query on that
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| 42 | #define RET_RUN_NEXT_A 3
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| 43 | // The CNAME query failed - stop resolving
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| 44 | #define RET_CNAME_FAIL 4
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| 45 | // We have a reliable input that claims that the hostname does not exist
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| 46 | #define RET_NOSUCHNAME 5
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| 47 | // The name server response is somehow bogus/can not be parsed -> Abort
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| 48 | #define RET_DNSERROR 6
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| 49 |
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| 50 | // Return values that the query engine may give
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| 51 | // DNS query succeeded, IP address delivered
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| 52 | #define RET_DNS_OK 0
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| 53 | // DNS query failed
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| 54 | #define RET_DNS_FAIL 1
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| 55 |
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| 56 | // Error codes the DNS server can send to us
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| 57 | #define ERR_NOSUCHNAME 3
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| 58 |
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