96 lines
2.2 KiB
Nim
96 lines
2.2 KiB
Nim
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from std/strutils import join
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import utils
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type
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Opcode* = enum
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QUERY = 0, IQUERY = 1, STATUS = 2
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type
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Rcode* = enum
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NO_ERROR = 0, FORMAT_ERROR = 1, SERVER_FAULURE = 2, NAME_ERROR = 3,
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NOT_IMPLEMENTED = 4, REFUSED = 5
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type
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DnsHeader* = object
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id*: uint16
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qr*: bool
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opcode*: Opcode
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aa*: bool
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tc*: bool
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rd*: bool
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ra*: bool
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z*: uint8
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rcode*: Rcode
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qdcount*: uint16
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ancount*: uint16
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nscount*: uint16
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arcount*: uint16
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proc parseHeader*(data: string): DnsHeader =
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assert len(data) >= 12
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return DnsHeader(
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id: toUInt16(data[1], data[0]),
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qr: sliceBit(data[2], 0),
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opcode: Opcode((toUint8(data[2]) shr 3) and 0b00001111),
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aa: sliceBit(data[2], 5),
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tc: sliceBit(data[2], 6),
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rd: sliceBit(data[2], 7),
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ra: sliceBit(data[3], 0),
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z: (toUint8(data[3]) shr 4) and 0b00000111,
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rcode: Rcode(toUint8(data[3]) and 0b00001111),
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qdcount: toUint16(data[5], data[4]),
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ancount: toUint16(data[7], data[6]),
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nscount: toUint16(data[9], data[8]),
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arcount: toUint16(data[11], data[10])
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)
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type
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DnsType* = enum
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A = 1, NS = 2, MD =3, MF =4, CNAME = 5, SOA = 6, MB = 7, MG = 8,
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MR = 9, NULL = 10, WKS = 11, PTR = 12, HINFO = 13, MINFO = 14, MX = 15,
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TXT = 16, AXFR = 252, MAILB = 253, MAILA = 254, ANY = 255
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type
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DnsClass* = enum
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IN = 1, CS = 2, CH = 3, HS = 4
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type
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DnsQuestion* = object
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qname*: string
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qtype*: DnsType
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qclass*: DnsClass
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proc parseQuestion*(data: string): (DnsQuestion, uint16) =
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var qname: seq[string] = @[]
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var len = toUint8(data[0])
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var offset: uint16 = 1
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while len > 0:
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qname.add(data[offset .. offset + len - 1])
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offset += len + 1
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len = toUint8(data[offset - 1])
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return (DnsQuestion(
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qname: qname.join("."),
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qtype: DnsType(toUint16(data[offset + 1], data[offset])),
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qclass: DnsClass(toUint16(data[offset + 3], data[offset + 2]))
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), offset + 4)
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type
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DnsRecord* = object
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name*: string
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rtype*: DnsType
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class*: DnsClass
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ttl*: uint32
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rdlength*: uint16
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rdata: string
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type
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DnsMessage* = object
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header*: DnsHeader
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questions*: seq[DnsQuestion]
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answer*: seq[DnsRecord]
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authroity*: seq[DnsRecord]
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additional*: seq[DnsRecord]
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