diff options
Diffstat (limited to 'src/cmd/fix/testdata/reflect.dnsmsg.go.in')
-rw-r--r-- | src/cmd/fix/testdata/reflect.dnsmsg.go.in | 777 |
1 files changed, 0 insertions, 777 deletions
diff --git a/src/cmd/fix/testdata/reflect.dnsmsg.go.in b/src/cmd/fix/testdata/reflect.dnsmsg.go.in deleted file mode 100644 index 3d9c312f2..000000000 --- a/src/cmd/fix/testdata/reflect.dnsmsg.go.in +++ /dev/null @@ -1,777 +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 net.Dial. -// It doesn't have to be blazing fast. -// -// Rather than write the usual handful of routines to pack and -// unpack every message that can appear on the wire, we use -// reflection to write a generic pack/unpack for structs and then -// use it. 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 - -import ( - "fmt" - "os" - "reflect" -) - -// 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 -) - -// The wire format for the DNS packet header. -type dnsHeader struct { - Id uint16 - Bits uint16 - Qdcount, Ancount, Nscount, Arcount uint16 -} - -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 "domain-name" // "domain-name" specifies encoding; see packers below - Qtype uint16 - Qclass uint16 -} - -// DNS responses (resource records). -// There are many types of messages, -// but they all share the same header. -type dnsRR_Header struct { - Name string "domain-name" - Rrtype uint16 - Class uint16 - Ttl uint32 - Rdlength uint16 // length of data after header -} - -func (h *dnsRR_Header) Header() *dnsRR_Header { - return h -} - -type dnsRR interface { - Header() *dnsRR_Header -} - -// Specific DNS RR formats for each query type. - -type dnsRR_CNAME struct { - Hdr dnsRR_Header - Cname string "domain-name" -} - -func (rr *dnsRR_CNAME) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_HINFO struct { - Hdr dnsRR_Header - Cpu string - Os string -} - -func (rr *dnsRR_HINFO) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_MB struct { - Hdr dnsRR_Header - Mb string "domain-name" -} - -func (rr *dnsRR_MB) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_MG struct { - Hdr dnsRR_Header - Mg string "domain-name" -} - -func (rr *dnsRR_MG) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_MINFO struct { - Hdr dnsRR_Header - Rmail string "domain-name" - Email string "domain-name" -} - -func (rr *dnsRR_MINFO) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_MR struct { - Hdr dnsRR_Header - Mr string "domain-name" -} - -func (rr *dnsRR_MR) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_MX struct { - Hdr dnsRR_Header - Pref uint16 - Mx string "domain-name" -} - -func (rr *dnsRR_MX) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_NS struct { - Hdr dnsRR_Header - Ns string "domain-name" -} - -func (rr *dnsRR_NS) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_PTR struct { - Hdr dnsRR_Header - Ptr string "domain-name" -} - -func (rr *dnsRR_PTR) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_SOA struct { - Hdr dnsRR_Header - Ns string "domain-name" - Mbox string "domain-name" - Serial uint32 - Refresh uint32 - Retry uint32 - Expire uint32 - Minttl uint32 -} - -func (rr *dnsRR_SOA) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_TXT struct { - Hdr dnsRR_Header - Txt string // not domain name -} - -func (rr *dnsRR_TXT) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_SRV struct { - Hdr dnsRR_Header - Priority uint16 - Weight uint16 - Port uint16 - Target string "domain-name" -} - -func (rr *dnsRR_SRV) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_A struct { - Hdr dnsRR_Header - A uint32 "ipv4" -} - -func (rr *dnsRR_A) Header() *dnsRR_Header { - return &rr.Hdr -} - -type dnsRR_AAAA struct { - Hdr dnsRR_Header - AAAA [16]byte "ipv6" -} - -func (rr *dnsRR_AAAA) Header() *dnsRR_Header { - return &rr.Hdr -} - -// 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 -} - -// TODO(rsc): Move into generic library? -// Pack a reflect.StructValue into msg. Struct members can only be uint16, uint32, string, -// [n]byte, and other (often anonymous) structs. -func packStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int, ok bool) { - for i := 0; i < val.NumField(); i++ { - f := val.Type().(*reflect.StructType).Field(i) - switch fv := val.Field(i).(type) { - default: - BadType: - fmt.Fprintf(os.Stderr, "net: dns: unknown packing type %v", f.Type) - return len(msg), false - case *reflect.StructValue: - off, ok = packStructValue(fv, msg, off) - case *reflect.UintValue: - i := fv.Get() - switch fv.Type().Kind() { - default: - goto BadType - case reflect.Uint16: - if off+2 > len(msg) { - return len(msg), false - } - msg[off] = byte(i >> 8) - msg[off+1] = byte(i) - off += 2 - case reflect.Uint32: - if off+4 > len(msg) { - return len(msg), false - } - 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 *reflect.ArrayValue: - if fv.Type().(*reflect.ArrayType).Elem().Kind() != reflect.Uint8 { - goto BadType - } - n := fv.Len() - if off+n > len(msg) { - return len(msg), false - } - reflect.Copy(reflect.NewValue(msg[off:off+n]).(*reflect.SliceValue), fv) - off += n - case *reflect.StringValue: - // There are multiple string encodings. - // The tag distinguishes ordinary strings from domain names. - s := fv.Get() - switch f.Tag { - default: - fmt.Fprintf(os.Stderr, "net: dns: unknown string tag %v", f.Tag) - return len(msg), false - case "domain-name": - off, ok = packDomainName(s, msg, off) - if !ok { - return len(msg), false - } - case "": - // Counted string: 1 byte length. - if len(s) > 255 || off+1+len(s) > len(msg) { - return len(msg), false - } - msg[off] = byte(len(s)) - off++ - off += copy(msg[off:], s) - } - } - } - return off, true -} - -func structValue(any interface{}) *reflect.StructValue { - return reflect.NewValue(any).(*reflect.PtrValue).Elem().(*reflect.StructValue) -} - -func packStruct(any interface{}, msg []byte, off int) (off1 int, ok bool) { - off, ok = packStructValue(structValue(any), msg, off) - return off, ok -} - -// TODO(rsc): Move into generic library? -// Unpack a reflect.StructValue from msg. -// Same restrictions as packStructValue. -func unpackStructValue(val *reflect.StructValue, msg []byte, off int) (off1 int, ok bool) { - for i := 0; i < val.NumField(); i++ { - f := val.Type().(*reflect.StructType).Field(i) - switch fv := val.Field(i).(type) { - default: - BadType: - fmt.Fprintf(os.Stderr, "net: dns: unknown packing type %v", f.Type) - return len(msg), false - case *reflect.StructValue: - off, ok = unpackStructValue(fv, msg, off) - case *reflect.UintValue: - switch fv.Type().Kind() { - default: - goto BadType - case reflect.Uint16: - if off+2 > len(msg) { - return len(msg), false - } - i := uint16(msg[off])<<8 | uint16(msg[off+1]) - fv.Set(uint64(i)) - off += 2 - case reflect.Uint32: - if off+4 > len(msg) { - return len(msg), false - } - i := uint32(msg[off])<<24 | uint32(msg[off+1])<<16 | uint32(msg[off+2])<<8 | uint32(msg[off+3]) - fv.Set(uint64(i)) - off += 4 - } - case *reflect.ArrayValue: - if fv.Type().(*reflect.ArrayType).Elem().Kind() != reflect.Uint8 { - goto BadType - } - n := fv.Len() - if off+n > len(msg) { - return len(msg), false - } - reflect.Copy(fv, reflect.NewValue(msg[off:off+n]).(*reflect.SliceValue)) - off += n - case *reflect.StringValue: - var s string - switch f.Tag { - default: - fmt.Fprintf(os.Stderr, "net: dns: unknown string tag %v", f.Tag) - return len(msg), false - case "domain-name": - s, off, ok = unpackDomainName(msg, off) - if !ok { - return len(msg), false - } - case "": - if off >= len(msg) || off+1+int(msg[off]) > len(msg) { - return len(msg), 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.Set(s) - } - } - return off, true -} - -func unpackStruct(any interface{}, msg []byte, off int) (off1 int, ok bool) { - off, ok = unpackStructValue(structValue(any), msg, off) - return off, ok -} - -// Generic struct printer. -// Doesn't care about the string tag "domain-name", -// but does look for an "ipv4" tag on uint32 variables -// and the "ipv6" tag on array variables, -// printing them as IP addresses. -func printStructValue(val *reflect.StructValue) string { - s := "{" - for i := 0; i < val.NumField(); i++ { - if i > 0 { - s += ", " - } - f := val.Type().(*reflect.StructType).Field(i) - if !f.Anonymous { - s += f.Name + "=" - } - fval := val.Field(i) - if fv, ok := fval.(*reflect.StructValue); ok { - s += printStructValue(fv) - } else if fv, ok := fval.(*reflect.UintValue); ok && f.Tag == "ipv4" { - i := fv.Get() - s += IPv4(byte(i>>24), byte(i>>16), byte(i>>8), byte(i)).String() - } else if fv, ok := fval.(*reflect.ArrayValue); ok && f.Tag == "ipv6" { - i := fv.Interface().([]byte) - s += IP(i).String() - } else { - s += fmt.Sprint(fval.Interface()) - } - } - s += "}" - return s -} - -func printStruct(any interface{}) string { return printStructValue(structValue(any)) } - -// 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 -} - -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, dh.Ancount) - dns.ns = make([]dnsRR, dh.Nscount) - dns.extra = make([]dnsRR, dh.Arcount) - - for i := 0; i < len(dns.question); i++ { - off, ok = unpackStruct(&dns.question[i], msg, off) - } - for i := 0; i < len(dns.answer); i++ { - dns.answer[i], off, ok = unpackRR(msg, off) - } - for i := 0; i < len(dns.ns); i++ { - dns.ns[i], off, ok = unpackRR(msg, off) - } - for i := 0; i < len(dns.extra); i++ { - dns.extra[i], off, ok = unpackRR(msg, off) - } - if !ok { - return false - } - // 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 -} |