mirror of
https://github.com/wader/fq.git
synced 2024-09-20 08:18:51 +03:00
2fc0a71a47
Move scalar into own package. Split scalar code into decode related scalar code (that reads etc) and scalar code that just transform the scalar value. Use a scalar.Mapper interface instead of just a function. Make mappers, assert and validat impement the interface.
283 lines
8.0 KiB
Go
283 lines
8.0 KiB
Go
package dns
|
|
|
|
// https://datatracker.ietf.org/doc/html/rfc1035
|
|
// https://github.com/Forescout/namewreck/blob/main/rfc/draft-dashevskyi-dnsrr-antipatterns-00.txt
|
|
|
|
import (
|
|
"net"
|
|
"strings"
|
|
|
|
"github.com/wader/fq/format"
|
|
"github.com/wader/fq/format/registry"
|
|
"github.com/wader/fq/pkg/decode"
|
|
"github.com/wader/fq/pkg/scalar"
|
|
)
|
|
|
|
func init() {
|
|
registry.MustRegister(decode.Format{
|
|
Name: format.DNS,
|
|
Description: "DNS packet",
|
|
Groups: []string{
|
|
format.TCP_STREAM,
|
|
format.UDP_PAYLOAD,
|
|
},
|
|
DecodeFn: dnsUDPDecode,
|
|
})
|
|
}
|
|
|
|
const (
|
|
classIN = 1
|
|
)
|
|
|
|
var classNames = scalar.URangeToScalar{
|
|
{0x0000, 0x0000}: {Sym: "Reserved", Description: "Reserved"},
|
|
{classIN, classIN}: {Sym: "IN", Description: "Internet"},
|
|
{0x0002, 0x0002}: {Sym: "Unassigned", Description: "Unassigned"},
|
|
{0x0003, 0x0003}: {Sym: "Chaos", Description: "Chaos"},
|
|
{0x0004, 0x0004}: {Sym: "Hesiod", Description: "Hesiod"},
|
|
{0x0005, 0x00fd}: {Sym: "Unassigned", Description: "Unassigned"},
|
|
{0x00fe, 0x00fe}: {Sym: "QCLASS_NONE", Description: "QCLASS NONE"},
|
|
{0x00ff, 0x00ff}: {Sym: "QCLASS_ANY", Description: "QCLASS ANY"},
|
|
{0x0100, 0xfeff}: {Sym: "Unassigned", Description: "Unassigned"},
|
|
{0xff00, 0xfffe}: {Sym: "Private", Description: "Reserved for Private Use"},
|
|
{0xffff, 0xffff}: {Sym: "Reserved", Description: "Reserved"},
|
|
}
|
|
|
|
const (
|
|
typeA = 1
|
|
typeNS = 2
|
|
typeCNAME = 5
|
|
typeSOA = 6
|
|
typePTR = 12
|
|
typeTXT = 16
|
|
typeAAAA = 28
|
|
)
|
|
|
|
var typeNames = scalar.UToSymStr{
|
|
typeA: "A",
|
|
typeAAAA: "AAAA",
|
|
18: "AFSDB",
|
|
42: "APL",
|
|
257: "CAA",
|
|
60: "CDNSKEY",
|
|
59: "CDS",
|
|
37: "CERT",
|
|
typeCNAME: "CNAME",
|
|
62: "CSYNC",
|
|
49: "DHCID",
|
|
32769: "DLV",
|
|
39: "DNAME",
|
|
48: "DNSKEY",
|
|
43: "DS",
|
|
108: "EUI48",
|
|
109: "EUI64",
|
|
13: "HINFO",
|
|
55: "HIP",
|
|
45: "IPSECKEY",
|
|
25: "KEY",
|
|
36: "KX",
|
|
29: "LOC",
|
|
15: "MX",
|
|
35: "NAPTR",
|
|
typeNS: "NS",
|
|
47: "NSEC",
|
|
50: "NSEC3",
|
|
51: "NSEC3PARAM",
|
|
61: "OPENPGPKEY",
|
|
typePTR: "PTR",
|
|
46: "RRSIG",
|
|
17: "RP",
|
|
24: "SIG",
|
|
53: "SMIMEA",
|
|
typeSOA: "SOA",
|
|
33: "SRV",
|
|
44: "SSHFP",
|
|
32768: "TA",
|
|
249: "TKEY",
|
|
52: "TLSA",
|
|
250: "TSIG",
|
|
typeTXT: "TXT",
|
|
256: "URI",
|
|
63: "ZONEMD",
|
|
64: "SVCB",
|
|
65: "HTTPS",
|
|
}
|
|
|
|
var rcodeNames = scalar.UToScalar{
|
|
0: {Sym: "NoError", Description: "No error"},
|
|
1: {Sym: "FormErr", Description: "Format error"},
|
|
2: {Sym: "ServFail", Description: "Server failure"},
|
|
3: {Sym: "NXDomain", Description: "Non-Existent Domain"},
|
|
4: {Sym: "NotiImpl", Description: "Not implemented"},
|
|
5: {Sym: "Refused", Description: "Refused"},
|
|
6: {Sym: "YXDomain", Description: "DescriptionName Exists when it should not"}, // RFC 2136
|
|
7: {Sym: "YXRRSet", Description: "RR Set Exists when it should not"}, // RFC 2136
|
|
8: {Sym: "NXRRSet", Description: "RR Set that should exist does not"}, // RFC 2136
|
|
9: {Sym: "NotAuth", Description: "Server Not Authoritative for zone"}, // RFC 2136
|
|
10: {Sym: "NotZone", Description: "Name not contained in zone"}, // RFC 2136
|
|
// collision in RFCs
|
|
// 16: {Sym: "BADVERS", Description: "Bad OPT Version"}, // RFC 2671
|
|
16: {Sym: "BADSIG", Description: "TSIG Signature Failure"}, // RFC 2845
|
|
17: {Sym: "BADKEY", Description: "Key not recognized"}, // RFC 2845
|
|
18: {Sym: "BADTIME", Description: "Signature out of time window"}, // RFC 2845
|
|
19: {Sym: "BADMODE", Description: "Bad TKEY Mode"}, // RFC 2930
|
|
20: {Sym: "BADNAME", Description: "Duplicate key name"}, // RFC 2930
|
|
21: {Sym: "BADALG", Description: "Algorithm not supported"}, // RFC 2930
|
|
}
|
|
|
|
func decodeAStr(d *decode.D) string {
|
|
return net.IP(d.BytesLen(4)).String()
|
|
}
|
|
|
|
func decodeAAAAStr(d *decode.D) string {
|
|
return net.IP(d.BytesLen(16)).String()
|
|
}
|
|
|
|
func fieldDecodeLabel(d *decode.D, pointerOffset int64, name string) {
|
|
var endPos int64
|
|
const maxJumps = 100
|
|
jumpCount := 0
|
|
|
|
d.FieldStruct(name, func(d *decode.D) {
|
|
var ls []string
|
|
d.FieldArray("labels", func(d *decode.D) {
|
|
seenTermintor := false
|
|
for !seenTermintor {
|
|
d.FieldStruct("label", func(d *decode.D) {
|
|
if d.PeekBits(2) == 0b11 {
|
|
d.FieldU2("is_pointer")
|
|
pointer := d.FieldU14("pointer")
|
|
if endPos == 0 {
|
|
endPos = d.Pos()
|
|
}
|
|
jumpCount++
|
|
if jumpCount > maxJumps {
|
|
d.Fatalf("label has more than %d jumps", maxJumps)
|
|
}
|
|
d.SeekAbs(int64(pointer)*8 + pointerOffset)
|
|
}
|
|
|
|
l := d.FieldU8("length")
|
|
if l == 0 {
|
|
seenTermintor = true
|
|
return
|
|
}
|
|
ls = append(ls, d.FieldUTF8("value", int(l)))
|
|
})
|
|
}
|
|
})
|
|
d.FieldValueStr("value", strings.Join(ls, "."))
|
|
})
|
|
|
|
if endPos != 0 {
|
|
d.SeekAbs(endPos)
|
|
}
|
|
}
|
|
|
|
func dnsDecodeRR(d *decode.D, pointerOffset int64, resp bool, count uint64, name string, structName string) {
|
|
d.FieldArray(name, func(d *decode.D) {
|
|
for i := uint64(0); i < count; i++ {
|
|
d.FieldStruct(structName, func(d *decode.D) {
|
|
fieldDecodeLabel(d, pointerOffset, "name")
|
|
typ := d.FieldU16("type", typeNames)
|
|
class := d.FieldU16("class", classNames)
|
|
if resp {
|
|
d.FieldU32("ttl")
|
|
rdLength := d.FieldU16("rdlength")
|
|
d.LenFn(int64(rdLength)*8, func(d *decode.D) {
|
|
// TODO: all only for classIN?
|
|
switch {
|
|
case class == classIN && typ == typeA:
|
|
d.FieldStrFn("address", decodeAStr)
|
|
case typ == typeNS:
|
|
fieldDecodeLabel(d, pointerOffset, "ns")
|
|
case typ == typeCNAME:
|
|
fieldDecodeLabel(d, pointerOffset, "cname")
|
|
case typ == typeSOA:
|
|
fieldDecodeLabel(d, pointerOffset, "mname")
|
|
fieldDecodeLabel(d, pointerOffset, "rname")
|
|
d.FieldU32("serial")
|
|
d.FieldU32("refresh")
|
|
d.FieldU32("retry")
|
|
d.FieldU32("expire")
|
|
d.FieldU32("minimum")
|
|
case typ == typePTR:
|
|
fieldDecodeLabel(d, pointerOffset, "ptr")
|
|
case typ == typeTXT:
|
|
var ss []string
|
|
d.FieldStruct("txt", func(d *decode.D) {
|
|
d.FieldArray("strings", func(d *decode.D) {
|
|
for !d.End() {
|
|
ss = append(ss, d.FieldUTF8ShortString("string"))
|
|
}
|
|
})
|
|
d.FieldValueStr("value", strings.Join(ss, ""))
|
|
})
|
|
case class == classIN && typ == typeAAAA:
|
|
d.FieldStrFn("address", decodeAAAAStr)
|
|
default:
|
|
d.FieldUTF8("rdata", int(rdLength))
|
|
}
|
|
})
|
|
}
|
|
})
|
|
}
|
|
})
|
|
}
|
|
|
|
func dnsDecode(d *decode.D, isTCP bool) interface{} {
|
|
pointerOffset := int64(0)
|
|
d.FieldStruct("header", func(d *decode.D) {
|
|
if isTCP {
|
|
pointerOffset = 16
|
|
d.FieldU16("length")
|
|
}
|
|
d.FieldU16("id")
|
|
d.FieldU1("qr", scalar.UToSymStr{
|
|
0: "query",
|
|
1: "response",
|
|
})
|
|
d.FieldU4("opcode", scalar.UToSymStr{
|
|
0: "Query",
|
|
1: "IQuery",
|
|
2: "Status",
|
|
4: "Notify", // RFC 1996
|
|
5: "Update", // RFC 2136
|
|
})
|
|
d.FieldBool("authoritative_answer")
|
|
d.FieldBool("truncation")
|
|
d.FieldBool("recursion_desired")
|
|
d.FieldBool("recursion_available")
|
|
d.FieldU3("z")
|
|
d.FieldU4("rcode", rcodeNames)
|
|
})
|
|
|
|
qdCount := d.FieldU16("qd_count")
|
|
anCount := d.FieldU16("an_count")
|
|
nsCount := d.FieldU16("ns_count")
|
|
arCount := d.FieldU16("ar_count")
|
|
dnsDecodeRR(d, pointerOffset, false, qdCount, "questions", "question")
|
|
dnsDecodeRR(d, pointerOffset, true, anCount, "answers", "answer")
|
|
dnsDecodeRR(d, pointerOffset, true, nsCount, "nameservers", "nameserver")
|
|
dnsDecodeRR(d, pointerOffset, true, arCount, "additionals", "additional")
|
|
|
|
return nil
|
|
}
|
|
|
|
func dnsUDPDecode(d *decode.D, in interface{}) interface{} {
|
|
if tsi, ok := in.(format.TCPStreamIn); ok {
|
|
if tsi.DestinationPort == format.TCPPortDomain || tsi.SourcePort == format.TCPPortDomain {
|
|
return dnsDecode(d, true)
|
|
}
|
|
d.Fatalf("wrong port")
|
|
}
|
|
if udi, ok := in.(format.UDPDatagramIn); ok {
|
|
if udi.DestinationPort == format.UDPPortDomain || udi.SourcePort == format.UDPPortDomain ||
|
|
udi.DestinationPort == format.UDPPortMDNS || udi.SourcePort == format.UDPPortMDNS {
|
|
return dnsDecode(d, false)
|
|
}
|
|
d.Fatalf("wrong port")
|
|
}
|
|
return dnsDecode(d, false)
|
|
}
|