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// Copyright 2012-2014 Apcera Inc. All rights reserved.
package server
import (
"fmt"
)
type pubArg struct {
subject []byte
reply []byte
sid []byte
szb []byte
size int
}
type parseState struct {
state int
as int
drop int
pa pubArg
argBuf []byte
msgBuf []byte
scratch [MAX_CONTROL_LINE_SIZE]byte
}
const (
OP_START = iota
OP_PLUS
OP_PLUS_O
OP_PLUS_OK
OP_MINUS
OP_MINUS_E
OP_MINUS_ER
OP_MINUS_ERR
OP_MINUS_ERR_SPC
MINUS_ERR_ARG
OP_C
OP_CO
OP_CON
OP_CONN
OP_CONNE
OP_CONNEC
OP_CONNECT
CONNECT_ARG
OP_P
OP_PU
OP_PUB
OP_PUB_SPC
PUB_ARG
OP_PI
OP_PIN
OP_PING
OP_PO
OP_PON
OP_PONG
MSG_PAYLOAD
MSG_END
OP_S
OP_SU
OP_SUB
OP_SUB_SPC
SUB_ARG
OP_U
OP_UN
OP_UNS
OP_UNSU
OP_UNSUB
UNSUB_ARG
OP_M
OP_MS
OP_MSG
OP_MSG_SPC
MSG_ARG
OP_I
OP_IN
OP_INF
OP_INFO
INFO_ARG
)
func (c *client) parse(buf []byte) error {
var i int
var b byte
// snapshot this, and reset when we receive a
// proper CONNECT if needed.
authSet := c.isAuthTimerSet()
// Move to loop instead of range syntax to allow jumping of i
for i = 0; i < len(buf); i++ {
b = buf[i]
switch c.state {
case OP_START:
if b != 'C' && b != 'c' && authSet {
goto authErr
}
switch b {
case 'P', 'p':
c.state = OP_P
case 'S', 's':
c.state = OP_S
case 'U', 'u':
c.state = OP_U
case 'M', 'm':
c.state = OP_M
case 'C', 'c':
c.state = OP_C
case 'I', 'i':
c.state = OP_I
case '+':
c.state = OP_PLUS
case '-':
c.state = OP_MINUS
default:
goto parseErr
}
case OP_P:
switch b {
case 'U', 'u':
c.state = OP_PU
case 'I', 'i':
c.state = OP_PI
case 'O', 'o':
c.state = OP_PO
default:
goto parseErr
}
case OP_PU:
switch b {
case 'B', 'b':
c.state = OP_PUB
default:
goto parseErr
}
case OP_PUB:
switch b {
case ' ', '\t':
c.state = OP_PUB_SPC
default:
goto parseErr
}
case OP_PUB_SPC:
switch b {
case ' ', '\t':
continue
default:
c.state = PUB_ARG
c.as = i
}
case PUB_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
} else {
arg = buf[c.as : i-c.drop]
}
if err := c.processPub(arg); err != nil {
return err
}
c.drop, c.as, c.state = 0, i+1, MSG_PAYLOAD
// If we don't have a saved buffer then jump ahead with
// the index. If this overruns what is left we fall out
// and process split buffer.
if c.msgBuf == nil {
i = c.as + c.pa.size - LEN_CR_LF
}
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
case MSG_PAYLOAD:
if c.msgBuf != nil {
// copy as much as we can to the buffer and skip ahead.
toCopy := c.pa.size - len(c.msgBuf)
avail := len(buf) - i
if avail < toCopy {
toCopy = avail
}
if toCopy > 0 {
start := len(c.msgBuf)
// This is needed for copy to work.
c.msgBuf = c.msgBuf[:start+toCopy]
copy(c.msgBuf[start:], buf[i:i+toCopy])
// Update our index
i = (i + toCopy) - 1
} else {
// Fall back to append if needed.
c.msgBuf = append(c.msgBuf, b)
}
if len(c.msgBuf) >= c.pa.size {
c.state = MSG_END
}
} else if i-c.as >= c.pa.size {
c.state = MSG_END
}
case MSG_END:
switch b {
case '\n':
if c.msgBuf != nil {
c.msgBuf = append(c.msgBuf, b)
} else {
c.msgBuf = buf[c.as : i+1]
}
// strict check for proto
if len(c.msgBuf) != c.pa.size+LEN_CR_LF {
goto parseErr
}
c.processMsg(c.msgBuf)
c.argBuf, c.msgBuf = nil, nil
c.drop, c.as, c.state = 0, i+1, OP_START
default:
if c.msgBuf != nil {
c.msgBuf = append(c.msgBuf, b)
}
continue
}
case OP_S:
switch b {
case 'U', 'u':
c.state = OP_SU
default:
goto parseErr
}
case OP_SU:
switch b {
case 'B', 'b':
c.state = OP_SUB
default:
goto parseErr
}
case OP_SUB:
switch b {
case ' ', '\t':
c.state = OP_SUB_SPC
default:
goto parseErr
}
case OP_SUB_SPC:
switch b {
case ' ', '\t':
continue
default:
c.state = SUB_ARG
c.as = i
}
case SUB_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
c.argBuf = nil
} else {
arg = buf[c.as : i-c.drop]
}
if err := c.processSub(arg); err != nil {
return err
}
c.drop, c.as, c.state = 0, i+1, OP_START
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
case OP_U:
switch b {
case 'N', 'n':
c.state = OP_UN
default:
goto parseErr
}
case OP_UN:
switch b {
case 'S', 's':
c.state = OP_UNS
default:
goto parseErr
}
case OP_UNS:
switch b {
case 'U', 'u':
c.state = OP_UNSU
default:
goto parseErr
}
case OP_UNSU:
switch b {
case 'B', 'b':
c.state = OP_UNSUB
default:
goto parseErr
}
case OP_UNSUB:
switch b {
case ' ', '\t':
continue
default:
c.state = UNSUB_ARG
c.as = i
}
case UNSUB_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
c.argBuf = nil
} else {
arg = buf[c.as : i-c.drop]
}
if err := c.processUnsub(arg); err != nil {
return err
}
c.drop, c.as, c.state = 0, i+1, OP_START
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
case OP_PI:
switch b {
case 'N', 'n':
c.state = OP_PIN
default:
goto parseErr
}
case OP_PIN:
switch b {
case 'G', 'g':
c.state = OP_PING
default:
goto parseErr
}
case OP_PING:
switch b {
case '\n':
c.processPing()
c.drop, c.state = 0, OP_START
}
case OP_PO:
switch b {
case 'N', 'n':
c.state = OP_PON
default:
goto parseErr
}
case OP_PON:
switch b {
case 'G', 'g':
c.state = OP_PONG
default:
goto parseErr
}
case OP_PONG:
switch b {
case '\n':
c.processPong()
c.drop, c.state = 0, OP_START
}
case OP_C:
switch b {
case 'O', 'o':
c.state = OP_CO
default:
goto parseErr
}
case OP_CO:
switch b {
case 'N', 'n':
c.state = OP_CON
default:
goto parseErr
}
case OP_CON:
switch b {
case 'N', 'n':
c.state = OP_CONN
default:
goto parseErr
}
case OP_CONN:
switch b {
case 'E', 'e':
c.state = OP_CONNE
default:
goto parseErr
}
case OP_CONNE:
switch b {
case 'C', 'c':
c.state = OP_CONNEC
default:
goto parseErr
}
case OP_CONNEC:
switch b {
case 'T', 't':
c.state = OP_CONNECT
default:
goto parseErr
}
case OP_CONNECT:
switch b {
case ' ', '\t':
continue
default:
c.state = CONNECT_ARG
c.as = i
}
case CONNECT_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
c.argBuf = nil
} else {
arg = buf[c.as : i-c.drop]
}
if err := c.processConnect(arg); err != nil {
return err
}
c.drop, c.state = 0, OP_START
// Reset notion on authSet
authSet = c.isAuthTimerSet()
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
case OP_M:
switch b {
case 'S', 's':
c.state = OP_MS
default:
goto parseErr
}
case OP_MS:
switch b {
case 'G', 'g':
c.state = OP_MSG
default:
goto parseErr
}
case OP_MSG:
switch b {
case ' ', '\t':
c.state = OP_MSG_SPC
default:
goto parseErr
}
case OP_MSG_SPC:
switch b {
case ' ', '\t':
continue
default:
c.state = MSG_ARG
c.as = i
}
case MSG_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
} else {
arg = buf[c.as : i-c.drop]
}
if err := c.processMsgArgs(arg); err != nil {
return err
}
c.drop, c.as, c.state = 0, i+1, MSG_PAYLOAD
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
case OP_I:
switch b {
case 'N', 'n':
c.state = OP_IN
default:
goto parseErr
}
case OP_IN:
switch b {
case 'F', 'f':
c.state = OP_INF
default:
goto parseErr
}
case OP_INF:
switch b {
case 'O', 'o':
c.state = OP_INFO
default:
goto parseErr
}
case OP_INFO:
switch b {
case ' ', '\t':
continue
default:
c.state = INFO_ARG
c.as = i
}
case INFO_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
if err := c.processInfo(buf[c.as : i-c.drop]); err != nil {
return err
}
c.drop, c.state = 0, OP_START
}
case OP_PLUS:
switch b {
case 'O', 'o':
c.state = OP_PLUS_O
default:
goto parseErr
}
case OP_PLUS_O:
switch b {
case 'K', 'k':
c.state = OP_PLUS_OK
default:
goto parseErr
}
case OP_PLUS_OK:
switch b {
case '\n':
c.drop, c.state = 0, OP_START
}
case OP_MINUS:
switch b {
case 'E', 'e':
c.state = OP_MINUS_E
default:
goto parseErr
}
case OP_MINUS_E:
switch b {
case 'R', 'r':
c.state = OP_MINUS_ER
default:
goto parseErr
}
case OP_MINUS_ER:
switch b {
case 'R', 'r':
c.state = OP_MINUS_ERR
default:
goto parseErr
}
case OP_MINUS_ERR:
switch b {
case ' ', '\t':
c.state = OP_MINUS_ERR_SPC
default:
goto parseErr
}
case OP_MINUS_ERR_SPC:
switch b {
case ' ', '\t':
continue
default:
c.state = MINUS_ERR_ARG
c.as = i
}
case MINUS_ERR_ARG:
switch b {
case '\r':
c.drop = 1
case '\n':
var arg []byte
if c.argBuf != nil {
arg = c.argBuf
c.argBuf = nil
} else {
arg = buf[c.as : i-c.drop]
}
c.processErr(string(arg))
c.drop, c.as, c.state = 0, i+1, OP_START
default:
if c.argBuf != nil {
c.argBuf = append(c.argBuf, b)
}
}
default:
goto parseErr
}
}
// Check for split buffer scenarios for any ARG state.
if (c.state == SUB_ARG || c.state == UNSUB_ARG || c.state == PUB_ARG ||
c.state == MSG_ARG || c.state == MINUS_ERR_ARG ||
c.state == CONNECT_ARG) && c.argBuf == nil {
c.argBuf = c.scratch[:0]
c.argBuf = append(c.argBuf, buf[c.as:i-c.drop]...)
// FIXME, check max len
}
// Check for split msg
if (c.state == MSG_PAYLOAD || c.state == MSG_END) && c.msgBuf == nil {
// We need to clone the pubArg if it is still referencing the
// read buffer and we are not able to process the msg.
if c.argBuf == nil {
c.clonePubArg()
}
// If we will overflow the scratch buffer, just create a
// new buffer to hold the split message.
if c.pa.size > cap(c.scratch)-len(c.argBuf) {
lrem := len(buf[c.as:])
c.msgBuf = make([]byte, lrem, c.pa.size+LEN_CR_LF)
copy(c.msgBuf, buf[c.as:])
} else {
c.msgBuf = c.scratch[len(c.argBuf):len(c.argBuf)]
c.msgBuf = append(c.msgBuf, (buf[c.as:])...)
}
}
return nil
authErr:
c.authViolation()
return ErrAuthorization
parseErr:
c.sendErr("Unknown Protocol Operation")
snip := protoSnippet(i, buf)
err := fmt.Errorf("%s Parser ERROR, state=%d, i=%d: proto='%s...'",
c.typeString(), c.state, i, snip)
return err
}
func protoSnippet(start int, buf []byte) string {
stop := start + PROTO_SNIPPET_SIZE
if stop > len(buf) {
stop = len(buf) - 1
}
return fmt.Sprintf("%q", buf[start:stop])
}
// clonePubArg is used when the split buffer scenario has the pubArg in the existing read buffer, but
// we need to hold onto it into the next read.
func (c *client) clonePubArg() {
c.argBuf = c.scratch[:0]
c.argBuf = append(c.argBuf, c.pa.subject...)
c.argBuf = append(c.argBuf, c.pa.reply...)
c.argBuf = append(c.argBuf, c.pa.sid...)
c.argBuf = append(c.argBuf, c.pa.szb...)
c.pa.subject = c.argBuf[:len(c.pa.subject)]
if c.pa.reply != nil {
c.pa.reply = c.argBuf[len(c.pa.subject) : len(c.pa.subject)+len(c.pa.reply)]
}
if c.pa.sid != nil {
c.pa.sid = c.argBuf[len(c.pa.subject)+len(c.pa.reply) : len(c.pa.subject)+len(c.pa.reply)+len(c.pa.sid)]
}
c.pa.szb = c.argBuf[len(c.pa.subject)+len(c.pa.reply)+len(c.pa.sid):]
}
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