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cloudflared-mirror/vendor/github.com/denisenkom/go-mssqldb/tds.go

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STOR-519: Add db-connect, a SQL over HTTPS server
2019-08-20 18:13:29 +00:00
package mssql
import (
"context"
"crypto/tls"
"crypto/x509"
"encoding/binary"
"errors"
"fmt"
"io"
"io/ioutil"
"net"
"net/url"
"os"
"sort"
"strconv"
"strings"
"time"
"unicode"
"unicode/utf16"
"unicode/utf8"
)
func parseInstances(msg []byte) map[string]map[string]string {
results := map[string]map[string]string{}
if len(msg) > 3 && msg[0] == 5 {
out_s := string(msg[3:])
tokens := strings.Split(out_s, ";")
instdict := map[string]string{}
got_name := false
var name string
for _, token := range tokens {
if got_name {
instdict[name] = token
got_name = false
} else {
name = token
if len(name) == 0 {
if len(instdict) == 0 {
break
}
results[strings.ToUpper(instdict["InstanceName"])] = instdict
instdict = map[string]string{}
continue
}
got_name = true
}
}
}
return results
}
func getInstances(ctx context.Context, d Dialer, address string) (map[string]map[string]string, error) {
maxTime := 5 * time.Second
ctx, cancel := context.WithTimeout(ctx, maxTime)
defer cancel()
conn, err := d.DialContext(ctx, "udp", address+":1434")
if err != nil {
return nil, err
}
defer conn.Close()
conn.SetDeadline(time.Now().Add(maxTime))
_, err = conn.Write([]byte{3})
if err != nil {
return nil, err
}
var resp = make([]byte, 16*1024-1)
read, err := conn.Read(resp)
if err != nil {
return nil, err
}
return parseInstances(resp[:read]), nil
}
// tds versions
const (
verTDS70 = 0x70000000
verTDS71 = 0x71000000
verTDS71rev1 = 0x71000001
verTDS72 = 0x72090002
verTDS73A = 0x730A0003
verTDS73 = verTDS73A
verTDS73B = 0x730B0003
verTDS74 = 0x74000004
)
// packet types
// https://msdn.microsoft.com/en-us/library/dd304214.aspx
const (
packSQLBatch packetType = 1
packRPCRequest = 3
packReply = 4
// 2.2.1.7 Attention: https://msdn.microsoft.com/en-us/library/dd341449.aspx
// 4.19.2 Out-of-Band Attention Signal: https://msdn.microsoft.com/en-us/library/dd305167.aspx
packAttention = 6
packBulkLoadBCP = 7
packTransMgrReq = 14
packNormal = 15
packLogin7 = 16
packSSPIMessage = 17
packPrelogin = 18
)
// prelogin fields
// http://msdn.microsoft.com/en-us/library/dd357559.aspx
const (
preloginVERSION = 0
preloginENCRYPTION = 1
preloginINSTOPT = 2
preloginTHREADID = 3
preloginMARS = 4
preloginTRACEID = 5
preloginTERMINATOR = 0xff
)
const (
encryptOff = 0 // Encryption is available but off.
encryptOn = 1 // Encryption is available and on.
encryptNotSup = 2 // Encryption is not available.
encryptReq = 3 // Encryption is required.
)
type tdsSession struct {
buf *tdsBuffer
loginAck loginAckStruct
database string
partner string
columns []columnStruct
tranid uint64
logFlags uint64
log optionalLogger
routedServer string
routedPort uint16
}
const (
logErrors = 1
logMessages = 2
logRows = 4
logSQL = 8
logParams = 16
logTransaction = 32
logDebug = 64
)
type columnStruct struct {
UserType uint32
Flags uint16
ColName string
ti typeInfo
}
type keySlice []uint8
func (p keySlice) Len() int { return len(p) }
func (p keySlice) Less(i, j int) bool { return p[i] < p[j] }
func (p keySlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
// http://msdn.microsoft.com/en-us/library/dd357559.aspx
func writePrelogin(w *tdsBuffer, fields map[uint8][]byte) error {
var err error
w.BeginPacket(packPrelogin, false)
offset := uint16(5*len(fields) + 1)
keys := make(keySlice, 0, len(fields))
for k, _ := range fields {
keys = append(keys, k)
}
sort.Sort(keys)
// writing header
for _, k := range keys {
err = w.WriteByte(k)
if err != nil {
return err
}
err = binary.Write(w, binary.BigEndian, offset)
if err != nil {
return err
}
v := fields[k]
size := uint16(len(v))
err = binary.Write(w, binary.BigEndian, size)
if err != nil {
return err
}
offset += size
}
err = w.WriteByte(preloginTERMINATOR)
if err != nil {
return err
}
// writing values
for _, k := range keys {
v := fields[k]
written, err := w.Write(v)
if err != nil {
return err
}
if written != len(v) {
return errors.New("Write method didn't write the whole value")
}
}
return w.FinishPacket()
}
func readPrelogin(r *tdsBuffer) (map[uint8][]byte, error) {
packet_type, err := r.BeginRead()
if err != nil {
return nil, err
}
struct_buf, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
if packet_type != 4 {
return nil, errors.New("Invalid respones, expected packet type 4, PRELOGIN RESPONSE")
}
offset := 0
results := map[uint8][]byte{}
for true {
rec_type := struct_buf[offset]
if rec_type == preloginTERMINATOR {
break
}
rec_offset := binary.BigEndian.Uint16(struct_buf[offset+1:])
rec_len := binary.BigEndian.Uint16(struct_buf[offset+3:])
value := struct_buf[rec_offset : rec_offset+rec_len]
results[rec_type] = value
offset += 5
}
return results, nil
}
// OptionFlags2
// http://msdn.microsoft.com/en-us/library/dd304019.aspx
const (
fLanguageFatal = 1
fODBC = 2
fTransBoundary = 4
fCacheConnect = 8
fIntSecurity = 0x80
)
// TypeFlags
const (
// 4 bits for fSQLType
// 1 bit for fOLEDB
fReadOnlyIntent = 32
)
type login struct {
TDSVersion uint32
PacketSize uint32
ClientProgVer uint32
ClientPID uint32
ConnectionID uint32
OptionFlags1 uint8
OptionFlags2 uint8
TypeFlags uint8
OptionFlags3 uint8
ClientTimeZone int32
ClientLCID uint32
HostName string
UserName string
Password string
AppName string
ServerName string
CtlIntName string
Language string
Database string
ClientID [6]byte
SSPI []byte
AtchDBFile string
ChangePassword string
}
type loginHeader struct {
Length uint32
TDSVersion uint32
PacketSize uint32
ClientProgVer uint32
ClientPID uint32
ConnectionID uint32
OptionFlags1 uint8
OptionFlags2 uint8
TypeFlags uint8
OptionFlags3 uint8
ClientTimeZone int32
ClientLCID uint32
HostNameOffset uint16
HostNameLength uint16
UserNameOffset uint16
UserNameLength uint16
PasswordOffset uint16
PasswordLength uint16
AppNameOffset uint16
AppNameLength uint16
ServerNameOffset uint16
ServerNameLength uint16
ExtensionOffset uint16
ExtensionLenght uint16
CtlIntNameOffset uint16
CtlIntNameLength uint16
LanguageOffset uint16
LanguageLength uint16
DatabaseOffset uint16
DatabaseLength uint16
ClientID [6]byte
SSPIOffset uint16
SSPILength uint16
AtchDBFileOffset uint16
AtchDBFileLength uint16
ChangePasswordOffset uint16
ChangePasswordLength uint16
SSPILongLength uint32
}
// convert Go string to UTF-16 encoded []byte (littleEndian)
// done manually rather than using bytes and binary packages
// for performance reasons
func str2ucs2(s string) []byte {
res := utf16.Encode([]rune(s))
ucs2 := make([]byte, 2*len(res))
for i := 0; i < len(res); i++ {
ucs2[2*i] = byte(res[i])
ucs2[2*i+1] = byte(res[i] >> 8)
}
return ucs2
}
func ucs22str(s []byte) (string, error) {
if len(s)%2 != 0 {
return "", fmt.Errorf("Illegal UCS2 string length: %d", len(s))
}
buf := make([]uint16, len(s)/2)
for i := 0; i < len(s); i += 2 {
buf[i/2] = binary.LittleEndian.Uint16(s[i:])
}
return string(utf16.Decode(buf)), nil
}
func manglePassword(password string) []byte {
var ucs2password []byte = str2ucs2(password)
for i, ch := range ucs2password {
ucs2password[i] = ((ch<<4)&0xff | (ch >> 4)) ^ 0xA5
}
return ucs2password
}
// http://msdn.microsoft.com/en-us/library/dd304019.aspx
func sendLogin(w *tdsBuffer, login login) error {
w.BeginPacket(packLogin7, false)
hostname := str2ucs2(login.HostName)
username := str2ucs2(login.UserName)
password := manglePassword(login.Password)
appname := str2ucs2(login.AppName)
servername := str2ucs2(login.ServerName)
ctlintname := str2ucs2(login.CtlIntName)
language := str2ucs2(login.Language)
database := str2ucs2(login.Database)
atchdbfile := str2ucs2(login.AtchDBFile)
changepassword := str2ucs2(login.ChangePassword)
hdr := loginHeader{
TDSVersion: login.TDSVersion,
PacketSize: login.PacketSize,
ClientProgVer: login.ClientProgVer,
ClientPID: login.ClientPID,
ConnectionID: login.ConnectionID,
OptionFlags1: login.OptionFlags1,
OptionFlags2: login.OptionFlags2,
TypeFlags: login.TypeFlags,
OptionFlags3: login.OptionFlags3,
ClientTimeZone: login.ClientTimeZone,
ClientLCID: login.ClientLCID,
HostNameLength: uint16(utf8.RuneCountInString(login.HostName)),
UserNameLength: uint16(utf8.RuneCountInString(login.UserName)),
PasswordLength: uint16(utf8.RuneCountInString(login.Password)),
AppNameLength: uint16(utf8.RuneCountInString(login.AppName)),
ServerNameLength: uint16(utf8.RuneCountInString(login.ServerName)),
CtlIntNameLength: uint16(utf8.RuneCountInString(login.CtlIntName)),
LanguageLength: uint16(utf8.RuneCountInString(login.Language)),
DatabaseLength: uint16(utf8.RuneCountInString(login.Database)),
ClientID: login.ClientID,
SSPILength: uint16(len(login.SSPI)),
AtchDBFileLength: uint16(utf8.RuneCountInString(login.AtchDBFile)),
ChangePasswordLength: uint16(utf8.RuneCountInString(login.ChangePassword)),
}
offset := uint16(binary.Size(hdr))
hdr.HostNameOffset = offset
offset += uint16(len(hostname))
hdr.UserNameOffset = offset
offset += uint16(len(username))
hdr.PasswordOffset = offset
offset += uint16(len(password))
hdr.AppNameOffset = offset
offset += uint16(len(appname))
hdr.ServerNameOffset = offset
offset += uint16(len(servername))
hdr.CtlIntNameOffset = offset
offset += uint16(len(ctlintname))
hdr.LanguageOffset = offset
offset += uint16(len(language))
hdr.DatabaseOffset = offset
offset += uint16(len(database))
hdr.SSPIOffset = offset
offset += uint16(len(login.SSPI))
hdr.AtchDBFileOffset = offset
offset += uint16(len(atchdbfile))
hdr.ChangePasswordOffset = offset
offset += uint16(len(changepassword))
hdr.Length = uint32(offset)
var err error
err = binary.Write(w, binary.LittleEndian, &hdr)
if err != nil {
return err
}
_, err = w.Write(hostname)
if err != nil {
return err
}
_, err = w.Write(username)
if err != nil {
return err
}
_, err = w.Write(password)
if err != nil {
return err
}
_, err = w.Write(appname)
if err != nil {
return err
}
_, err = w.Write(servername)
if err != nil {
return err
}
_, err = w.Write(ctlintname)
if err != nil {
return err
}
_, err = w.Write(language)
if err != nil {
return err
}
_, err = w.Write(database)
if err != nil {
return err
}
_, err = w.Write(login.SSPI)
if err != nil {
return err
}
_, err = w.Write(atchdbfile)
if err != nil {
return err
}
_, err = w.Write(changepassword)
if err != nil {
return err
}
return w.FinishPacket()
}
func readUcs2(r io.Reader, numchars int) (res string, err error) {
buf := make([]byte, numchars*2)
_, err = io.ReadFull(r, buf)
if err != nil {
return "", err
}
return ucs22str(buf)
}
func readUsVarChar(r io.Reader) (res string, err error) {
var numchars uint16
err = binary.Read(r, binary.LittleEndian, &numchars)
if err != nil {
return "", err
}
return readUcs2(r, int(numchars))
}
func writeUsVarChar(w io.Writer, s string) (err error) {
buf := str2ucs2(s)
var numchars int = len(buf) / 2
if numchars > 0xffff {
panic("invalid size for US_VARCHAR")
}
err = binary.Write(w, binary.LittleEndian, uint16(numchars))
if err != nil {
return
}
_, err = w.Write(buf)
return
}
func readBVarChar(r io.Reader) (res string, err error) {
var numchars uint8
err = binary.Read(r, binary.LittleEndian, &numchars)
if err != nil {
return "", err
}
// A zero length could be returned, return an empty string
if numchars == 0 {
return "", nil
}
return readUcs2(r, int(numchars))
}
func writeBVarChar(w io.Writer, s string) (err error) {
buf := str2ucs2(s)
var numchars int = len(buf) / 2
if numchars > 0xff {
panic("invalid size for B_VARCHAR")
}
err = binary.Write(w, binary.LittleEndian, uint8(numchars))
if err != nil {
return
}
_, err = w.Write(buf)
return
}
func readBVarByte(r io.Reader) (res []byte, err error) {
var length uint8
err = binary.Read(r, binary.LittleEndian, &length)
if err != nil {
return
}
res = make([]byte, length)
_, err = io.ReadFull(r, res)
return
}
func readUshort(r io.Reader) (res uint16, err error) {
err = binary.Read(r, binary.LittleEndian, &res)
return
}
func readByte(r io.Reader) (res byte, err error) {
var b [1]byte
_, err = r.Read(b[:])
res = b[0]
return
}
// Packet Data Stream Headers
// http://msdn.microsoft.com/en-us/library/dd304953.aspx
type headerStruct struct {
hdrtype uint16
data []byte
}
const (
dataStmHdrQueryNotif = 1 // query notifications
dataStmHdrTransDescr = 2 // MARS transaction descriptor (required)
dataStmHdrTraceActivity = 3
)
// Query Notifications Header
// http://msdn.microsoft.com/en-us/library/dd304949.aspx
type queryNotifHdr struct {
notifyId string
ssbDeployment string
notifyTimeout uint32
}
func (hdr queryNotifHdr) pack() (res []byte) {
notifyId := str2ucs2(hdr.notifyId)
ssbDeployment := str2ucs2(hdr.ssbDeployment)
res = make([]byte, 2+len(notifyId)+2+len(ssbDeployment)+4)
b := res
binary.LittleEndian.PutUint16(b, uint16(len(notifyId)))
b = b[2:]
copy(b, notifyId)
b = b[len(notifyId):]
binary.LittleEndian.PutUint16(b, uint16(len(ssbDeployment)))
b = b[2:]
copy(b, ssbDeployment)
b = b[len(ssbDeployment):]
binary.LittleEndian.PutUint32(b, hdr.notifyTimeout)
return res
}
// MARS Transaction Descriptor Header
// http://msdn.microsoft.com/en-us/library/dd340515.aspx
type transDescrHdr struct {
transDescr uint64 // transaction descriptor returned from ENVCHANGE
outstandingReqCnt uint32 // outstanding request count
}
func (hdr transDescrHdr) pack() (res []byte) {
res = make([]byte, 8+4)
binary.LittleEndian.PutUint64(res, hdr.transDescr)
binary.LittleEndian.PutUint32(res[8:], hdr.outstandingReqCnt)
return res
}
func writeAllHeaders(w io.Writer, headers []headerStruct) (err error) {
// Calculating total length.
var totallen uint32 = 4
for _, hdr := range headers {
totallen += 4 + 2 + uint32(len(hdr.data))
}
// writing
err = binary.Write(w, binary.LittleEndian, totallen)
if err != nil {
return err
}
for _, hdr := range headers {
var headerlen uint32 = 4 + 2 + uint32(len(hdr.data))
err = binary.Write(w, binary.LittleEndian, headerlen)
if err != nil {
return err
}
err = binary.Write(w, binary.LittleEndian, hdr.hdrtype)
if err != nil {
return err
}
_, err = w.Write(hdr.data)
if err != nil {
return err
}
}
return nil
}
func sendSqlBatch72(buf *tdsBuffer, sqltext string, headers []headerStruct, resetSession bool) (err error) {
buf.BeginPacket(packSQLBatch, resetSession)
if err = writeAllHeaders(buf, headers); err != nil {
return
}
_, err = buf.Write(str2ucs2(sqltext))
if err != nil {
return
}
return buf.FinishPacket()
}
// 2.2.1.7 Attention: https://msdn.microsoft.com/en-us/library/dd341449.aspx
// 4.19.2 Out-of-Band Attention Signal: https://msdn.microsoft.com/en-us/library/dd305167.aspx
func sendAttention(buf *tdsBuffer) error {
buf.BeginPacket(packAttention, false)
return buf.FinishPacket()
}
type connectParams struct {
logFlags uint64
port uint64
host string
instance string
database string
user string
password string
dial_timeout time.Duration
conn_timeout time.Duration
keepAlive time.Duration
encrypt bool
disableEncryption bool
trustServerCertificate bool
certificate string
hostInCertificate string
hostInCertificateProvided bool
serverSPN string
workstation string
appname string
typeFlags uint8
failOverPartner string
failOverPort uint64
packetSize uint16
}
func splitConnectionString(dsn string) (res map[string]string) {
res = map[string]string{}
parts := strings.Split(dsn, ";")
for _, part := range parts {
if len(part) == 0 {
continue
}
lst := strings.SplitN(part, "=", 2)
name := strings.TrimSpace(strings.ToLower(lst[0]))
if len(name) == 0 {
continue
}
var value string = ""
if len(lst) > 1 {
value = strings.TrimSpace(lst[1])
}
res[name] = value
}
return res
}
// Splits a URL in the ODBC format
func splitConnectionStringOdbc(dsn string) (map[string]string, error) {
res := map[string]string{}
type parserState int
const (
// Before the start of a key
parserStateBeforeKey parserState = iota
// Inside a key
parserStateKey
// Beginning of a value. May be bare or braced
parserStateBeginValue
// Inside a bare value
parserStateBareValue
// Inside a braced value
parserStateBracedValue
// A closing brace inside a braced value.
// May be the end of the value or an escaped closing brace, depending on the next character
parserStateBracedValueClosingBrace
// After a value. Next character should be a semicolon or whitespace.
parserStateEndValue
)
var state = parserStateBeforeKey
var key string
var value string
for i, c := range dsn {
switch state {
case parserStateBeforeKey:
switch {
case c == '=':
return res, fmt.Errorf("Unexpected character = at index %d. Expected start of key or semi-colon or whitespace.", i)
case !unicode.IsSpace(c) && c != ';':
state = parserStateKey
key += string(c)
}
case parserStateKey:
switch c {
case '=':
key = normalizeOdbcKey(key)
if len(key) == 0 {
return res, fmt.Errorf("Unexpected end of key at index %d.", i)
}
state = parserStateBeginValue
case ';':
// Key without value
key = normalizeOdbcKey(key)
if len(key) == 0 {
return res, fmt.Errorf("Unexpected end of key at index %d.", i)
}
res[key] = value
key = ""
value = ""
state = parserStateBeforeKey
default:
key += string(c)
}
case parserStateBeginValue:
switch {
case c == '{':
state = parserStateBracedValue
case c == ';':
// Empty value
res[key] = value
key = ""
state = parserStateBeforeKey
case unicode.IsSpace(c):
// Ignore whitespace
default:
state = parserStateBareValue
value += string(c)
}
case parserStateBareValue:
if c == ';' {
res[key] = strings.TrimRightFunc(value, unicode.IsSpace)
key = ""
value = ""
state = parserStateBeforeKey
} else {
value += string(c)
}
case parserStateBracedValue:
if c == '}' {
state = parserStateBracedValueClosingBrace
} else {
value += string(c)
}
case parserStateBracedValueClosingBrace:
if c == '}' {
// Escaped closing brace
value += string(c)
state = parserStateBracedValue
continue
}
// End of braced value
res[key] = value
key = ""
value = ""
// This character is the first character past the end,
// so it needs to be parsed like the parserStateEndValue state.
state = parserStateEndValue
switch {
case c == ';':
state = parserStateBeforeKey
case unicode.IsSpace(c):
// Ignore whitespace
default:
return res, fmt.Errorf("Unexpected character %c at index %d. Expected semi-colon or whitespace.", c, i)
}
case parserStateEndValue:
switch {
case c == ';':
state = parserStateBeforeKey
case unicode.IsSpace(c):
// Ignore whitespace
default:
return res, fmt.Errorf("Unexpected character %c at index %d. Expected semi-colon or whitespace.", c, i)
}
}
}
switch state {
case parserStateBeforeKey: // Okay
case parserStateKey: // Unfinished key. Treat as key without value.
key = normalizeOdbcKey(key)
if len(key) == 0 {
return res, fmt.Errorf("Unexpected end of key at index %d.", len(dsn))
}
res[key] = value
case parserStateBeginValue: // Empty value
res[key] = value
case parserStateBareValue:
res[key] = strings.TrimRightFunc(value, unicode.IsSpace)
case parserStateBracedValue:
return res, fmt.Errorf("Unexpected end of braced value at index %d.", len(dsn))
case parserStateBracedValueClosingBrace: // End of braced value
res[key] = value
case parserStateEndValue: // Okay
}
return res, nil
}
// Normalizes the given string as an ODBC-format key
func normalizeOdbcKey(s string) string {
return strings.ToLower(strings.TrimRightFunc(s, unicode.IsSpace))
}
// Splits a URL of the form sqlserver://username:password@host/instance?param1=value&param2=value
func splitConnectionStringURL(dsn string) (map[string]string, error) {
res := map[string]string{}
u, err := url.Parse(dsn)
if err != nil {
return res, err
}
if u.Scheme != "sqlserver" {
return res, fmt.Errorf("scheme %s is not recognized", u.Scheme)
}
if u.User != nil {
res["user id"] = u.User.Username()
p, exists := u.User.Password()
if exists {
res["password"] = p
}
}
host, port, err := net.SplitHostPort(u.Host)
if err != nil {
host = u.Host
}
if len(u.Path) > 0 {
res["server"] = host + "\\" + u.Path[1:]
} else {
res["server"] = host
}
if len(port) > 0 {
res["port"] = port
}
query := u.Query()
for k, v := range query {
if len(v) > 1 {
return res, fmt.Errorf("key %s provided more than once", k)
}
res[strings.ToLower(k)] = v[0]
}
return res, nil
}
func parseConnectParams(dsn string) (connectParams, error) {
var p connectParams
var params map[string]string
if strings.HasPrefix(dsn, "odbc:") {
parameters, err := splitConnectionStringOdbc(dsn[len("odbc:"):])
if err != nil {
return p, err
}
params = parameters
} else if strings.HasPrefix(dsn, "sqlserver://") {
parameters, err := splitConnectionStringURL(dsn)
if err != nil {
return p, err
}
params = parameters
} else {
params = splitConnectionString(dsn)
}
strlog, ok := params["log"]
if ok {
var err error
p.logFlags, err = strconv.ParseUint(strlog, 10, 64)
if err != nil {
return p, fmt.Errorf("Invalid log parameter '%s': %s", strlog, err.Error())
}
}
server := params["server"]
parts := strings.SplitN(server, `\`, 2)
p.host = parts[0]
if p.host == "." || strings.ToUpper(p.host) == "(LOCAL)" || p.host == "" {
p.host = "localhost"
}
if len(parts) > 1 {
p.instance = parts[1]
}
p.database = params["database"]
p.user = params["user id"]
p.password = params["password"]
p.port = 1433
strport, ok := params["port"]
if ok {
var err error
p.port, err = strconv.ParseUint(strport, 10, 16)
if err != nil {
f := "Invalid tcp port '%v': %v"
return p, fmt.Errorf(f, strport, err.Error())
}
}
// https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/configure-the-network-packet-size-server-configuration-option
// Default packet size remains at 4096 bytes
p.packetSize = 4096
strpsize, ok := params["packet size"]
if ok {
var err error
psize, err := strconv.ParseUint(strpsize, 0, 16)
if err != nil {
f := "Invalid packet size '%v': %v"
return p, fmt.Errorf(f, strpsize, err.Error())
}
// Ensure packet size falls within the TDS protocol range of 512 to 32767 bytes
// NOTE: Encrypted connections have a maximum size of 16383 bytes. If you request
// a higher packet size, the server will respond with an ENVCHANGE request to
// alter the packet size to 16383 bytes.
p.packetSize = uint16(psize)
if p.packetSize < 512 {
p.packetSize = 512
} else if p.packetSize > 32767 {
p.packetSize = 32767
}
}
// https://msdn.microsoft.com/en-us/library/dd341108.aspx
//
// Do not set a connection timeout. Use Context to manage such things.
// Default to zero, but still allow it to be set.
if strconntimeout, ok := params["connection timeout"]; ok {
timeout, err := strconv.ParseUint(strconntimeout, 10, 64)
if err != nil {
f := "Invalid connection timeout '%v': %v"
return p, fmt.Errorf(f, strconntimeout, err.Error())
}
p.conn_timeout = time.Duration(timeout) * time.Second
}
p.dial_timeout = 15 * time.Second
if strdialtimeout, ok := params["dial timeout"]; ok {
timeout, err := strconv.ParseUint(strdialtimeout, 10, 64)
if err != nil {
f := "Invalid dial timeout '%v': %v"
return p, fmt.Errorf(f, strdialtimeout, err.Error())
}
p.dial_timeout = time.Duration(timeout) * time.Second
}
// default keep alive should be 30 seconds according to spec:
// https://msdn.microsoft.com/en-us/library/dd341108.aspx
p.keepAlive = 30 * time.Second
if keepAlive, ok := params["keepalive"]; ok {
timeout, err := strconv.ParseUint(keepAlive, 10, 64)
if err != nil {
f := "Invalid keepAlive value '%s': %s"
return p, fmt.Errorf(f, keepAlive, err.Error())
}
p.keepAlive = time.Duration(timeout) * time.Second
}
encrypt, ok := params["encrypt"]
if ok {
if strings.EqualFold(encrypt, "DISABLE") {
p.disableEncryption = true
} else {
var err error
p.encrypt, err = strconv.ParseBool(encrypt)
if err != nil {
f := "Invalid encrypt '%s': %s"
return p, fmt.Errorf(f, encrypt, err.Error())
}
}
} else {
p.trustServerCertificate = true
}
trust, ok := params["trustservercertificate"]
if ok {
var err error
p.trustServerCertificate, err = strconv.ParseBool(trust)
if err != nil {
f := "Invalid trust server certificate '%s': %s"
return p, fmt.Errorf(f, trust, err.Error())
}
}
p.certificate = params["certificate"]
p.hostInCertificate, ok = params["hostnameincertificate"]
if ok {
p.hostInCertificateProvided = true
} else {
p.hostInCertificate = p.host
p.hostInCertificateProvided = false
}
serverSPN, ok := params["serverspn"]
if ok {
p.serverSPN = serverSPN
} else {
p.serverSPN = fmt.Sprintf("MSSQLSvc/%s:%d", p.host, p.port)
}
workstation, ok := params["workstation id"]
if ok {
p.workstation = workstation
} else {
workstation, err := os.Hostname()
if err == nil {
p.workstation = workstation
}
}
appname, ok := params["app name"]
if !ok {
appname = "go-mssqldb"
}
p.appname = appname
appintent, ok := params["applicationintent"]
if ok {
if appintent == "ReadOnly" {
p.typeFlags |= fReadOnlyIntent
}
}
failOverPartner, ok := params["failoverpartner"]
if ok {
p.failOverPartner = failOverPartner
}
failOverPort, ok := params["failoverport"]
if ok {
var err error
p.failOverPort, err = strconv.ParseUint(failOverPort, 0, 16)
if err != nil {
f := "Invalid tcp port '%v': %v"
return p, fmt.Errorf(f, failOverPort, err.Error())
}
}
return p, nil
}
type auth interface {
InitialBytes() ([]byte, error)
NextBytes([]byte) ([]byte, error)
Free()
}
// SQL Server AlwaysOn Availability Group Listeners are bound by DNS to a
// list of IP addresses. So if there is more than one, try them all and
// use the first one that allows a connection.
func dialConnection(ctx context.Context, c *Connector, p connectParams) (conn net.Conn, err error) {
var ips []net.IP
ips, err = net.LookupIP(p.host)
if err != nil {
ip := net.ParseIP(p.host)
if ip == nil {
return nil, err
}
ips = []net.IP{ip}
}
if len(ips) == 1 {
d := c.getDialer(&p)
addr := net.JoinHostPort(ips[0].String(), strconv.Itoa(int(p.port)))
conn, err = d.DialContext(ctx, "tcp", addr)
} else {
//Try Dials in parallel to avoid waiting for timeouts.
connChan := make(chan net.Conn, len(ips))
errChan := make(chan error, len(ips))
portStr := strconv.Itoa(int(p.port))
for _, ip := range ips {
go func(ip net.IP) {
d := c.getDialer(&p)
addr := net.JoinHostPort(ip.String(), portStr)
conn, err := d.DialContext(ctx, "tcp", addr)
if err == nil {
connChan <- conn
} else {
errChan <- err
}
}(ip)
}
// Wait for either the *first* successful connection, or all the errors
wait_loop:
for i, _ := range ips {
select {
case conn = <-connChan:
// Got a connection to use, close any others
go func(n int) {
for i := 0; i < n; i++ {
select {
case conn := <-connChan:
conn.Close()
case <-errChan:
}
}
}(len(ips) - i - 1)
// Remove any earlier errors we may have collected
err = nil
break wait_loop
case err = <-errChan:
}
}
}
// Can't do the usual err != nil check, as it is possible to have gotten an error before a successful connection
if conn == nil {
f := "Unable to open tcp connection with host '%v:%v': %v"
return nil, fmt.Errorf(f, p.host, p.port, err.Error())
}
return conn, err
}
func connect(ctx context.Context, c *Connector, log optionalLogger, p connectParams) (res *tdsSession, err error) {
dialCtx := ctx
if p.dial_timeout > 0 {
var cancel func()
dialCtx, cancel = context.WithTimeout(ctx, p.dial_timeout)
defer cancel()
}
// if instance is specified use instance resolution service
if p.instance != "" {
p.instance = strings.ToUpper(p.instance)
d := c.getDialer(&p)
instances, err := getInstances(dialCtx, d, p.host)
if err != nil {
f := "Unable to get instances from Sql Server Browser on host %v: %v"
return nil, fmt.Errorf(f, p.host, err.Error())
}
strport, ok := instances[p.instance]["tcp"]
if !ok {
f := "No instance matching '%v' returned from host '%v'"
return nil, fmt.Errorf(f, p.instance, p.host)
}
p.port, err = strconv.ParseUint(strport, 0, 16)
if err != nil {
f := "Invalid tcp port returned from Sql Server Browser '%v': %v"
return nil, fmt.Errorf(f, strport, err.Error())
}
}
initiate_connection:
conn, err := dialConnection(dialCtx, c, p)
if err != nil {
return nil, err
}
toconn := newTimeoutConn(conn, p.conn_timeout)
outbuf := newTdsBuffer(p.packetSize, toconn)
sess := tdsSession{
buf: outbuf,
log: log,
logFlags: p.logFlags,
}
instance_buf := []byte(p.instance)
instance_buf = append(instance_buf, 0) // zero terminate instance name
var encrypt byte
if p.disableEncryption {
encrypt = encryptNotSup
} else if p.encrypt {
encrypt = encryptOn
} else {
encrypt = encryptOff
}
fields := map[uint8][]byte{
preloginVERSION: {0, 0, 0, 0, 0, 0},
preloginENCRYPTION: {encrypt},
preloginINSTOPT: instance_buf,
preloginTHREADID: {0, 0, 0, 0},
preloginMARS: {0}, // MARS disabled
}
err = writePrelogin(outbuf, fields)
if err != nil {
return nil, err
}
fields, err = readPrelogin(outbuf)
if err != nil {
return nil, err
}
encryptBytes, ok := fields[preloginENCRYPTION]
if !ok {
return nil, fmt.Errorf("Encrypt negotiation failed")
}
encrypt = encryptBytes[0]
if p.encrypt && (encrypt == encryptNotSup || encrypt == encryptOff) {
return nil, fmt.Errorf("Server does not support encryption")
}
if encrypt != encryptNotSup {
var config tls.Config
if p.certificate != "" {
pem, err := ioutil.ReadFile(p.certificate)
if err != nil {
return nil, fmt.Errorf("Cannot read certificate %q: %v", p.certificate, err)
}
certs := x509.NewCertPool()
certs.AppendCertsFromPEM(pem)
config.RootCAs = certs
}
if p.trustServerCertificate {
config.InsecureSkipVerify = true
}
config.ServerName = p.hostInCertificate
// fix for https://github.com/denisenkom/go-mssqldb/issues/166
// Go implementation of TLS payload size heuristic algorithm splits single TDS package to multiple TCP segments,
// while SQL Server seems to expect one TCP segment per encrypted TDS package.
// Setting DynamicRecordSizingDisabled to true disables that algorithm and uses 16384 bytes per TLS package
config.DynamicRecordSizingDisabled = true
outbuf.transport = conn
toconn.buf = outbuf
tlsConn := tls.Client(toconn, &config)
err = tlsConn.Handshake()
toconn.buf = nil
outbuf.transport = tlsConn
if err != nil {
return nil, fmt.Errorf("TLS Handshake failed: %v", err)
}
if encrypt == encryptOff {
outbuf.afterFirst = func() {
outbuf.transport = toconn
}
}
}
login := login{
TDSVersion: verTDS74,
PacketSize: uint32(outbuf.PackageSize()),
Database: p.database,
OptionFlags2: fODBC, // to get unlimited TEXTSIZE
HostName: p.workstation,
ServerName: p.host,
AppName: p.appname,
TypeFlags: p.typeFlags,
}
auth, auth_ok := getAuth(p.user, p.password, p.serverSPN, p.workstation)
if auth_ok {
login.SSPI, err = auth.InitialBytes()
if err != nil {
return nil, err
}
login.OptionFlags2 |= fIntSecurity
defer auth.Free()
} else {
login.UserName = p.user
login.Password = p.password
}
err = sendLogin(outbuf, login)
if err != nil {
return nil, err
}
// processing login response
success := false
for {
tokchan := make(chan tokenStruct, 5)
go processResponse(context.Background(), &sess, tokchan, nil)
for tok := range tokchan {
switch token := tok.(type) {
case sspiMsg:
sspi_msg, err := auth.NextBytes(token)
if err != nil {
return nil, err
}
if sspi_msg != nil && len(sspi_msg) > 0 {
outbuf.BeginPacket(packSSPIMessage, false)
_, err = outbuf.Write(sspi_msg)
if err != nil {
return nil, err
}
err = outbuf.FinishPacket()
if err != nil {
return nil, err
}
sspi_msg = nil
}
case loginAckStruct:
success = true
sess.loginAck = token
case error:
return nil, fmt.Errorf("Login error: %s", token.Error())
case doneStruct:
if token.isError() {
return nil, fmt.Errorf("Login error: %s", token.getError())
}
goto loginEnd
}
}
}
loginEnd:
if !success {
return nil, fmt.Errorf("Login failed")
}
if sess.routedServer != "" {
toconn.Close()
p.host = sess.routedServer
p.port = uint64(sess.routedPort)
if !p.hostInCertificateProvided {
p.hostInCertificate = sess.routedServer
}
goto initiate_connection
}
return &sess, nil
}