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path: root/src/pkg/net/dnsmsg.go
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Diffstat (limited to 'src/pkg/net/dnsmsg.go')
-rw-r--r--src/pkg/net/dnsmsg.go887
1 files changed, 0 insertions, 887 deletions
diff --git a/src/pkg/net/dnsmsg.go b/src/pkg/net/dnsmsg.go
deleted file mode 100644
index 161afb2a5..000000000
--- a/src/pkg/net/dnsmsg.go
+++ /dev/null
@@ -1,887 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// DNS packet assembly. See RFC 1035.
-//
-// This is intended to support name resolution during Dial.
-// It doesn't have to be blazing fast.
-//
-// Each message structure has a Walk method that is used by
-// a generic pack/unpack routine. Thus, if in the future we need
-// to define new message structs, no new pack/unpack/printing code
-// needs to be written.
-//
-// The first half of this file defines the DNS message formats.
-// The second half implements the conversion to and from wire format.
-// A few of the structure elements have string tags to aid the
-// generic pack/unpack routines.
-//
-// TODO(rsc): There are enough names defined in this file that they're all
-// prefixed with dns. Perhaps put this in its own package later.
-
-package net
-
-// Packet formats
-
-// Wire constants.
-const (
- // valid dnsRR_Header.Rrtype and dnsQuestion.qtype
- dnsTypeA = 1
- dnsTypeNS = 2
- dnsTypeMD = 3
- dnsTypeMF = 4
- dnsTypeCNAME = 5
- dnsTypeSOA = 6
- dnsTypeMB = 7
- dnsTypeMG = 8
- dnsTypeMR = 9
- dnsTypeNULL = 10
- dnsTypeWKS = 11
- dnsTypePTR = 12
- dnsTypeHINFO = 13
- dnsTypeMINFO = 14
- dnsTypeMX = 15
- dnsTypeTXT = 16
- dnsTypeAAAA = 28
- dnsTypeSRV = 33
-
- // valid dnsQuestion.qtype only
- dnsTypeAXFR = 252
- dnsTypeMAILB = 253
- dnsTypeMAILA = 254
- dnsTypeALL = 255
-
- // valid dnsQuestion.qclass
- dnsClassINET = 1
- dnsClassCSNET = 2
- dnsClassCHAOS = 3
- dnsClassHESIOD = 4
- dnsClassANY = 255
-
- // dnsMsg.rcode
- dnsRcodeSuccess = 0
- dnsRcodeFormatError = 1
- dnsRcodeServerFailure = 2
- dnsRcodeNameError = 3
- dnsRcodeNotImplemented = 4
- dnsRcodeRefused = 5
-)
-
-// A dnsStruct describes how to iterate over its fields to emulate
-// reflective marshalling.
-type dnsStruct interface {
- // Walk iterates over fields of a structure and calls f
- // with a reference to that field, the name of the field
- // and a tag ("", "domain", "ipv4", "ipv6") specifying
- // particular encodings. Possible concrete types
- // for v are *uint16, *uint32, *string, or []byte, and
- // *int, *bool in the case of dnsMsgHdr.
- // Whenever f returns false, Walk must stop and return
- // false, and otherwise return true.
- Walk(f func(v interface{}, name, tag string) (ok bool)) (ok bool)
-}
-
-// The wire format for the DNS packet header.
-type dnsHeader struct {
- Id uint16
- Bits uint16
- Qdcount, Ancount, Nscount, Arcount uint16
-}
-
-func (h *dnsHeader) Walk(f func(v interface{}, name, tag string) bool) bool {
- return f(&h.Id, "Id", "") &&
- f(&h.Bits, "Bits", "") &&
- f(&h.Qdcount, "Qdcount", "") &&
- f(&h.Ancount, "Ancount", "") &&
- f(&h.Nscount, "Nscount", "") &&
- f(&h.Arcount, "Arcount", "")
-}
-
-const (
- // dnsHeader.Bits
- _QR = 1 << 15 // query/response (response=1)
- _AA = 1 << 10 // authoritative
- _TC = 1 << 9 // truncated
- _RD = 1 << 8 // recursion desired
- _RA = 1 << 7 // recursion available
-)
-
-// DNS queries.
-type dnsQuestion struct {
- Name string `net:"domain-name"` // `net:"domain-name"` specifies encoding; see packers below
- Qtype uint16
- Qclass uint16
-}
-
-func (q *dnsQuestion) Walk(f func(v interface{}, name, tag string) bool) bool {
- return f(&q.Name, "Name", "domain") &&
- f(&q.Qtype, "Qtype", "") &&
- f(&q.Qclass, "Qclass", "")
-}
-
-// DNS responses (resource records).
-// There are many types of messages,
-// but they all share the same header.
-type dnsRR_Header struct {
- Name string `net:"domain-name"`
- Rrtype uint16
- Class uint16
- Ttl uint32
- Rdlength uint16 // length of data after header
-}
-
-func (h *dnsRR_Header) Header() *dnsRR_Header {
- return h
-}
-
-func (h *dnsRR_Header) Walk(f func(v interface{}, name, tag string) bool) bool {
- return f(&h.Name, "Name", "domain") &&
- f(&h.Rrtype, "Rrtype", "") &&
- f(&h.Class, "Class", "") &&
- f(&h.Ttl, "Ttl", "") &&
- f(&h.Rdlength, "Rdlength", "")
-}
-
-type dnsRR interface {
- dnsStruct
- Header() *dnsRR_Header
-}
-
-// Specific DNS RR formats for each query type.
-
-type dnsRR_CNAME struct {
- Hdr dnsRR_Header
- Cname string `net:"domain-name"`
-}
-
-func (rr *dnsRR_CNAME) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_CNAME) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Cname, "Cname", "domain")
-}
-
-type dnsRR_HINFO struct {
- Hdr dnsRR_Header
- Cpu string
- Os string
-}
-
-func (rr *dnsRR_HINFO) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_HINFO) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Cpu, "Cpu", "") && f(&rr.Os, "Os", "")
-}
-
-type dnsRR_MB struct {
- Hdr dnsRR_Header
- Mb string `net:"domain-name"`
-}
-
-func (rr *dnsRR_MB) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_MB) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Mb, "Mb", "domain")
-}
-
-type dnsRR_MG struct {
- Hdr dnsRR_Header
- Mg string `net:"domain-name"`
-}
-
-func (rr *dnsRR_MG) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_MG) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Mg, "Mg", "domain")
-}
-
-type dnsRR_MINFO struct {
- Hdr dnsRR_Header
- Rmail string `net:"domain-name"`
- Email string `net:"domain-name"`
-}
-
-func (rr *dnsRR_MINFO) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_MINFO) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Rmail, "Rmail", "domain") && f(&rr.Email, "Email", "domain")
-}
-
-type dnsRR_MR struct {
- Hdr dnsRR_Header
- Mr string `net:"domain-name"`
-}
-
-func (rr *dnsRR_MR) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_MR) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Mr, "Mr", "domain")
-}
-
-type dnsRR_MX struct {
- Hdr dnsRR_Header
- Pref uint16
- Mx string `net:"domain-name"`
-}
-
-func (rr *dnsRR_MX) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_MX) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Pref, "Pref", "") && f(&rr.Mx, "Mx", "domain")
-}
-
-type dnsRR_NS struct {
- Hdr dnsRR_Header
- Ns string `net:"domain-name"`
-}
-
-func (rr *dnsRR_NS) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_NS) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Ns, "Ns", "domain")
-}
-
-type dnsRR_PTR struct {
- Hdr dnsRR_Header
- Ptr string `net:"domain-name"`
-}
-
-func (rr *dnsRR_PTR) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_PTR) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Ptr, "Ptr", "domain")
-}
-
-type dnsRR_SOA struct {
- Hdr dnsRR_Header
- Ns string `net:"domain-name"`
- Mbox string `net:"domain-name"`
- Serial uint32
- Refresh uint32
- Retry uint32
- Expire uint32
- Minttl uint32
-}
-
-func (rr *dnsRR_SOA) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_SOA) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) &&
- f(&rr.Ns, "Ns", "domain") &&
- f(&rr.Mbox, "Mbox", "domain") &&
- f(&rr.Serial, "Serial", "") &&
- f(&rr.Refresh, "Refresh", "") &&
- f(&rr.Retry, "Retry", "") &&
- f(&rr.Expire, "Expire", "") &&
- f(&rr.Minttl, "Minttl", "")
-}
-
-type dnsRR_TXT struct {
- Hdr dnsRR_Header
- Txt string // not domain name
-}
-
-func (rr *dnsRR_TXT) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_TXT) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.Txt, "Txt", "")
-}
-
-type dnsRR_SRV struct {
- Hdr dnsRR_Header
- Priority uint16
- Weight uint16
- Port uint16
- Target string `net:"domain-name"`
-}
-
-func (rr *dnsRR_SRV) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_SRV) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) &&
- f(&rr.Priority, "Priority", "") &&
- f(&rr.Weight, "Weight", "") &&
- f(&rr.Port, "Port", "") &&
- f(&rr.Target, "Target", "domain")
-}
-
-type dnsRR_A struct {
- Hdr dnsRR_Header
- A uint32 `net:"ipv4"`
-}
-
-func (rr *dnsRR_A) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_A) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(&rr.A, "A", "ipv4")
-}
-
-type dnsRR_AAAA struct {
- Hdr dnsRR_Header
- AAAA [16]byte `net:"ipv6"`
-}
-
-func (rr *dnsRR_AAAA) Header() *dnsRR_Header {
- return &rr.Hdr
-}
-
-func (rr *dnsRR_AAAA) Walk(f func(v interface{}, name, tag string) bool) bool {
- return rr.Hdr.Walk(f) && f(rr.AAAA[:], "AAAA", "ipv6")
-}
-
-// Packing and unpacking.
-//
-// All the packers and unpackers take a (msg []byte, off int)
-// and return (off1 int, ok bool). If they return ok==false, they
-// also return off1==len(msg), so that the next unpacker will
-// also fail. This lets us avoid checks of ok until the end of a
-// packing sequence.
-
-// Map of constructors for each RR wire type.
-var rr_mk = map[int]func() dnsRR{
- dnsTypeCNAME: func() dnsRR { return new(dnsRR_CNAME) },
- dnsTypeHINFO: func() dnsRR { return new(dnsRR_HINFO) },
- dnsTypeMB: func() dnsRR { return new(dnsRR_MB) },
- dnsTypeMG: func() dnsRR { return new(dnsRR_MG) },
- dnsTypeMINFO: func() dnsRR { return new(dnsRR_MINFO) },
- dnsTypeMR: func() dnsRR { return new(dnsRR_MR) },
- dnsTypeMX: func() dnsRR { return new(dnsRR_MX) },
- dnsTypeNS: func() dnsRR { return new(dnsRR_NS) },
- dnsTypePTR: func() dnsRR { return new(dnsRR_PTR) },
- dnsTypeSOA: func() dnsRR { return new(dnsRR_SOA) },
- dnsTypeTXT: func() dnsRR { return new(dnsRR_TXT) },
- dnsTypeSRV: func() dnsRR { return new(dnsRR_SRV) },
- dnsTypeA: func() dnsRR { return new(dnsRR_A) },
- dnsTypeAAAA: func() dnsRR { return new(dnsRR_AAAA) },
-}
-
-// Pack a domain name s into msg[off:].
-// Domain names are a sequence of counted strings
-// split at the dots. They end with a zero-length string.
-func packDomainName(s string, msg []byte, off int) (off1 int, ok bool) {
- // Add trailing dot to canonicalize name.
- if n := len(s); n == 0 || s[n-1] != '.' {
- s += "."
- }
-
- // Each dot ends a segment of the name.
- // We trade each dot byte for a length byte.
- // There is also a trailing zero.
- // Check that we have all the space we need.
- tot := len(s) + 1
- if off+tot > len(msg) {
- return len(msg), false
- }
-
- // Emit sequence of counted strings, chopping at dots.
- begin := 0
- for i := 0; i < len(s); i++ {
- if s[i] == '.' {
- if i-begin >= 1<<6 { // top two bits of length must be clear
- return len(msg), false
- }
- msg[off] = byte(i - begin)
- off++
- for j := begin; j < i; j++ {
- msg[off] = s[j]
- off++
- }
- begin = i + 1
- }
- }
- msg[off] = 0
- off++
- return off, true
-}
-
-// Unpack a domain name.
-// In addition to the simple sequences of counted strings above,
-// domain names are allowed to refer to strings elsewhere in the
-// packet, to avoid repeating common suffixes when returning
-// many entries in a single domain. The pointers are marked
-// by a length byte with the top two bits set. Ignoring those
-// two bits, that byte and the next give a 14 bit offset from msg[0]
-// where we should pick up the trail.
-// Note that if we jump elsewhere in the packet,
-// we return off1 == the offset after the first pointer we found,
-// which is where the next record will start.
-// In theory, the pointers are only allowed to jump backward.
-// We let them jump anywhere and stop jumping after a while.
-func unpackDomainName(msg []byte, off int) (s string, off1 int, ok bool) {
- s = ""
- ptr := 0 // number of pointers followed
-Loop:
- for {
- if off >= len(msg) {
- return "", len(msg), false
- }
- c := int(msg[off])
- off++
- switch c & 0xC0 {
- case 0x00:
- if c == 0x00 {
- // end of name
- break Loop
- }
- // literal string
- if off+c > len(msg) {
- return "", len(msg), false
- }
- s += string(msg[off:off+c]) + "."
- off += c
- case 0xC0:
- // pointer to somewhere else in msg.
- // remember location after first ptr,
- // since that's how many bytes we consumed.
- // also, don't follow too many pointers --
- // maybe there's a loop.
- if off >= len(msg) {
- return "", len(msg), false
- }
- c1 := msg[off]
- off++
- if ptr == 0 {
- off1 = off
- }
- if ptr++; ptr > 10 {
- return "", len(msg), false
- }
- off = (c^0xC0)<<8 | int(c1)
- default:
- // 0x80 and 0x40 are reserved
- return "", len(msg), false
- }
- }
- if ptr == 0 {
- off1 = off
- }
- return s, off1, true
-}
-
-// packStruct packs a structure into msg at specified offset off, and
-// returns off1 such that msg[off:off1] is the encoded data.
-func packStruct(any dnsStruct, msg []byte, off int) (off1 int, ok bool) {
- ok = any.Walk(func(field interface{}, name, tag string) bool {
- switch fv := field.(type) {
- default:
- println("net: dns: unknown packing type")
- return false
- case *uint16:
- i := *fv
- if off+2 > len(msg) {
- return false
- }
- msg[off] = byte(i >> 8)
- msg[off+1] = byte(i)
- off += 2
- case *uint32:
- i := *fv
- msg[off] = byte(i >> 24)
- msg[off+1] = byte(i >> 16)
- msg[off+2] = byte(i >> 8)
- msg[off+3] = byte(i)
- off += 4
- case []byte:
- n := len(fv)
- if off+n > len(msg) {
- return false
- }
- copy(msg[off:off+n], fv)
- off += n
- case *string:
- s := *fv
- switch tag {
- default:
- println("net: dns: unknown string tag", tag)
- return false
- case "domain":
- off, ok = packDomainName(s, msg, off)
- if !ok {
- return false
- }
- case "":
- // Counted string: 1 byte length.
- if len(s) > 255 || off+1+len(s) > len(msg) {
- return false
- }
- msg[off] = byte(len(s))
- off++
- off += copy(msg[off:], s)
- }
- }
- return true
- })
- if !ok {
- return len(msg), false
- }
- return off, true
-}
-
-// unpackStruct decodes msg[off:] into the given structure, and
-// returns off1 such that msg[off:off1] is the encoded data.
-func unpackStruct(any dnsStruct, msg []byte, off int) (off1 int, ok bool) {
- ok = any.Walk(func(field interface{}, name, tag string) bool {
- switch fv := field.(type) {
- default:
- println("net: dns: unknown packing type")
- return false
- case *uint16:
- if off+2 > len(msg) {
- return false
- }
- *fv = uint16(msg[off])<<8 | uint16(msg[off+1])
- off += 2
- case *uint32:
- if off+4 > len(msg) {
- return false
- }
- *fv = uint32(msg[off])<<24 | uint32(msg[off+1])<<16 |
- uint32(msg[off+2])<<8 | uint32(msg[off+3])
- off += 4
- case []byte:
- n := len(fv)
- if off+n > len(msg) {
- return false
- }
- copy(fv, msg[off:off+n])
- off += n
- case *string:
- var s string
- switch tag {
- default:
- println("net: dns: unknown string tag", tag)
- return false
- case "domain":
- s, off, ok = unpackDomainName(msg, off)
- if !ok {
- return false
- }
- case "":
- if off >= len(msg) || off+1+int(msg[off]) > len(msg) {
- return false
- }
- n := int(msg[off])
- off++
- b := make([]byte, n)
- for i := 0; i < n; i++ {
- b[i] = msg[off+i]
- }
- off += n
- s = string(b)
- }
- *fv = s
- }
- return true
- })
- if !ok {
- return len(msg), false
- }
- return off, true
-}
-
-// Generic struct printer. Prints fields with tag "ipv4" or "ipv6"
-// as IP addresses.
-func printStruct(any dnsStruct) string {
- s := "{"
- i := 0
- any.Walk(func(val interface{}, name, tag string) bool {
- i++
- if i > 1 {
- s += ", "
- }
- s += name + "="
- switch tag {
- case "ipv4":
- i := *val.(*uint32)
- s += IPv4(byte(i>>24), byte(i>>16), byte(i>>8), byte(i)).String()
- case "ipv6":
- i := val.([]byte)
- s += IP(i).String()
- default:
- var i int64
- switch v := val.(type) {
- default:
- // can't really happen.
- s += "<unknown type>"
- return true
- case *string:
- s += *v
- return true
- case []byte:
- s += string(v)
- return true
- case *bool:
- if *v {
- s += "true"
- } else {
- s += "false"
- }
- return true
- case *int:
- i = int64(*v)
- case *uint:
- i = int64(*v)
- case *uint8:
- i = int64(*v)
- case *uint16:
- i = int64(*v)
- case *uint32:
- i = int64(*v)
- case *uint64:
- i = int64(*v)
- case *uintptr:
- i = int64(*v)
- }
- s += itoa(int(i))
- }
- return true
- })
- s += "}"
- return s
-}
-
-// Resource record packer.
-func packRR(rr dnsRR, msg []byte, off int) (off2 int, ok bool) {
- var off1 int
- // pack twice, once to find end of header
- // and again to find end of packet.
- // a bit inefficient but this doesn't need to be fast.
- // off1 is end of header
- // off2 is end of rr
- off1, ok = packStruct(rr.Header(), msg, off)
- off2, ok = packStruct(rr, msg, off)
- if !ok {
- return len(msg), false
- }
- // pack a third time; redo header with correct data length
- rr.Header().Rdlength = uint16(off2 - off1)
- packStruct(rr.Header(), msg, off)
- return off2, true
-}
-
-// Resource record unpacker.
-func unpackRR(msg []byte, off int) (rr dnsRR, off1 int, ok bool) {
- // unpack just the header, to find the rr type and length
- var h dnsRR_Header
- off0 := off
- if off, ok = unpackStruct(&h, msg, off); !ok {
- return nil, len(msg), false
- }
- end := off + int(h.Rdlength)
-
- // make an rr of that type and re-unpack.
- // again inefficient but doesn't need to be fast.
- mk, known := rr_mk[int(h.Rrtype)]
- if !known {
- return &h, end, true
- }
- rr = mk()
- off, ok = unpackStruct(rr, msg, off0)
- if off != end {
- return &h, end, true
- }
- return rr, off, ok
-}
-
-// Usable representation of a DNS packet.
-
-// A manually-unpacked version of (id, bits).
-// This is in its own struct for easy printing.
-type dnsMsgHdr struct {
- id uint16
- response bool
- opcode int
- authoritative bool
- truncated bool
- recursion_desired bool
- recursion_available bool
- rcode int
-}
-
-func (h *dnsMsgHdr) Walk(f func(v interface{}, name, tag string) bool) bool {
- return f(&h.id, "id", "") &&
- f(&h.response, "response", "") &&
- f(&h.opcode, "opcode", "") &&
- f(&h.authoritative, "authoritative", "") &&
- f(&h.truncated, "truncated", "") &&
- f(&h.recursion_desired, "recursion_desired", "") &&
- f(&h.recursion_available, "recursion_available", "") &&
- f(&h.rcode, "rcode", "")
-}
-
-type dnsMsg struct {
- dnsMsgHdr
- question []dnsQuestion
- answer []dnsRR
- ns []dnsRR
- extra []dnsRR
-}
-
-func (dns *dnsMsg) Pack() (msg []byte, ok bool) {
- var dh dnsHeader
-
- // Convert convenient dnsMsg into wire-like dnsHeader.
- dh.Id = dns.id
- dh.Bits = uint16(dns.opcode)<<11 | uint16(dns.rcode)
- if dns.recursion_available {
- dh.Bits |= _RA
- }
- if dns.recursion_desired {
- dh.Bits |= _RD
- }
- if dns.truncated {
- dh.Bits |= _TC
- }
- if dns.authoritative {
- dh.Bits |= _AA
- }
- if dns.response {
- dh.Bits |= _QR
- }
-
- // Prepare variable sized arrays.
- question := dns.question
- answer := dns.answer
- ns := dns.ns
- extra := dns.extra
-
- dh.Qdcount = uint16(len(question))
- dh.Ancount = uint16(len(answer))
- dh.Nscount = uint16(len(ns))
- dh.Arcount = uint16(len(extra))
-
- // Could work harder to calculate message size,
- // but this is far more than we need and not
- // big enough to hurt the allocator.
- msg = make([]byte, 2000)
-
- // Pack it in: header and then the pieces.
- off := 0
- off, ok = packStruct(&dh, msg, off)
- for i := 0; i < len(question); i++ {
- off, ok = packStruct(&question[i], msg, off)
- }
- for i := 0; i < len(answer); i++ {
- off, ok = packRR(answer[i], msg, off)
- }
- for i := 0; i < len(ns); i++ {
- off, ok = packRR(ns[i], msg, off)
- }
- for i := 0; i < len(extra); i++ {
- off, ok = packRR(extra[i], msg, off)
- }
- if !ok {
- return nil, false
- }
- return msg[0:off], true
-}
-
-func (dns *dnsMsg) Unpack(msg []byte) bool {
- // Header.
- var dh dnsHeader
- off := 0
- var ok bool
- if off, ok = unpackStruct(&dh, msg, off); !ok {
- return false
- }
- dns.id = dh.Id
- dns.response = (dh.Bits & _QR) != 0
- dns.opcode = int(dh.Bits>>11) & 0xF
- dns.authoritative = (dh.Bits & _AA) != 0
- dns.truncated = (dh.Bits & _TC) != 0
- dns.recursion_desired = (dh.Bits & _RD) != 0
- dns.recursion_available = (dh.Bits & _RA) != 0
- dns.rcode = int(dh.Bits & 0xF)
-
- // Arrays.
- dns.question = make([]dnsQuestion, dh.Qdcount)
- dns.answer = make([]dnsRR, 0, dh.Ancount)
- dns.ns = make([]dnsRR, 0, dh.Nscount)
- dns.extra = make([]dnsRR, 0, dh.Arcount)
-
- var rec dnsRR
-
- for i := 0; i < len(dns.question); i++ {
- off, ok = unpackStruct(&dns.question[i], msg, off)
- }
- for i := 0; i < int(dh.Ancount); i++ {
- rec, off, ok = unpackRR(msg, off)
- if !ok {
- return false
- }
- dns.answer = append(dns.answer, rec)
- }
- for i := 0; i < int(dh.Nscount); i++ {
- rec, off, ok = unpackRR(msg, off)
- if !ok {
- return false
- }
- dns.ns = append(dns.ns, rec)
- }
- for i := 0; i < int(dh.Arcount); i++ {
- rec, off, ok = unpackRR(msg, off)
- if !ok {
- return false
- }
- dns.extra = append(dns.extra, rec)
- }
- // if off != len(msg) {
- // println("extra bytes in dns packet", off, "<", len(msg));
- // }
- return true
-}
-
-func (dns *dnsMsg) String() string {
- s := "DNS: " + printStruct(&dns.dnsMsgHdr) + "\n"
- if len(dns.question) > 0 {
- s += "-- Questions\n"
- for i := 0; i < len(dns.question); i++ {
- s += printStruct(&dns.question[i]) + "\n"
- }
- }
- if len(dns.answer) > 0 {
- s += "-- Answers\n"
- for i := 0; i < len(dns.answer); i++ {
- s += printStruct(dns.answer[i]) + "\n"
- }
- }
- if len(dns.ns) > 0 {
- s += "-- Name servers\n"
- for i := 0; i < len(dns.ns); i++ {
- s += printStruct(dns.ns[i]) + "\n"
- }
- }
- if len(dns.extra) > 0 {
- s += "-- Extra\n"
- for i := 0; i < len(dns.extra); i++ {
- s += printStruct(dns.extra[i]) + "\n"
- }
- }
- return s
-}
generated by cgit v1.2.3 (git 2.39.1) at 2025-04-29 16:04:42 +0000