X-Git-Url: http://git.nikiroo.be/?p=nikiroo-utils.git;a=blobdiff_plain;f=src%2Fjexer%2Fnet%2FTelnetInputStream.java;h=d8164a4567d6f5d15a88e49b4e2221ce024a7c61;hp=f409b7a6d17084fe021a9cbeb4920f1a087f6d4e;hb=9b1afdde02c30f0d4a80ba330a4bc72384093253;hpb=005ec49709aab8590ee9571f17a67440969c6248 diff --git a/src/jexer/net/TelnetInputStream.java b/src/jexer/net/TelnetInputStream.java index f409b7a..d8164a4 100644 --- a/src/jexer/net/TelnetInputStream.java +++ b/src/jexer/net/TelnetInputStream.java @@ -32,6 +32,7 @@ package jexer.net; import java.io.InputStream; import java.io.IOException; +import java.util.ArrayList; import java.util.Map; import java.util.TreeMap; @@ -41,7 +42,8 @@ import static jexer.net.TelnetSocket.*; /** * TelnetInputStream works with TelnetSocket to perform the telnet protocol. */ -public final class TelnetInputStream extends InputStream implements SessionInfo { +public final class TelnetInputStream extends InputStream + implements SessionInfo { /** * The root TelnetSocket that has my telnet protocol state. @@ -94,6 +96,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo readBuffer = new byte[1024]; readBufferStart = 0; readBufferEnd = 0; + subnegBuffer = new ArrayList(); } // SessionInfo interface -------------------------------------------------- @@ -186,6 +189,10 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * skipped over) from this input stream without blocking by the next * invocation of a method for this input stream. * + * @return an estimate of the number of bytes that can be read (or + * skipped over) from this input stream without blocking or 0 when it + * reaches the end of the input stream. + * @throws IOException if an I/O error occurs */ @Override public int available() throws IOException { @@ -201,6 +208,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Closes this input stream and releases any system resources associated * with the stream. + * + * @throws IOException if an I/O error occurs */ @Override public void close() throws IOException { @@ -212,14 +221,20 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Marks the current position in this input stream. + * + * @param readLimit the maximum limit of bytes that can be read before + * the mark position becomes invalid */ @Override - public void mark(int readlimit) { + public void mark(final int readLimit) { // Do nothing } /** * Tests if this input stream supports the mark and reset methods. + * + * @return true if this stream instance supports the mark and reset + * methods; false otherwise */ @Override public boolean markSupported() { @@ -228,6 +243,10 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Reads the next byte of data from the input stream. + * + * @return the next byte of data, or -1 if there is no more data because + * the end of the stream has been reached. + * @throws IOException if an I/O error occurs */ @Override public int read() throws IOException { @@ -261,18 +280,32 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Reads some number of bytes from the input stream and stores them into * the buffer array b. + * + * @param b the buffer into which the data is read. + * @return the total number of bytes read into the buffer, or -1 if there + * is no more data because the end of the stream has been reached. + * @throws IOException if an I/O error occurs */ @Override - public int read(byte[] b) throws IOException { + public int read(final byte[] b) throws IOException { return read(b, 0, b.length); } /** * Reads up to len bytes of data from the input stream into an array of * bytes. + * + * @param b the buffer into which the data is read. + * @param off the start offset in array b at which the data is written. + * @param len the maximum number of bytes to read. + * @return the total number of bytes read into the buffer, or -1 if there + * is no more data because the end of the stream has been reached. + * @throws IOException if an I/O error occurs */ @Override - public int read(byte[] b, int off, int len) throws IOException { + public int read(final byte[] b, final int off, + final int len) throws IOException { + // The only time we can return 0 is if len is 0, as per the // InputStream contract. if (len == 0) { @@ -300,7 +333,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo // If we got something, return it. if (rc > 0) { - System.arraycopy(readBuffer, 0, b, off, len); + System.arraycopy(readBuffer, 0, b, off, rc); return rc; } // If we read 0, I screwed up big time. @@ -312,7 +345,10 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Repositions this stream to the position at the time the mark method - * was last called on this input stream. + * was last called on this input stream. This is not supported by + * TelnetInputStream, so IOException is always thrown. + * + * @throws IOException if this function is used */ @Override public void reset() throws IOException { @@ -321,9 +357,13 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Skips over and discards n bytes of data from this input stream. + * + * @param n the number of bytes to be skipped + * @return the actual number of bytes skipped + * @throws IOException if an I/O error occurs */ @Override - public long skip(long n) throws IOException { + public long skip(final long n) throws IOException { if (n < 0) { return 0; } @@ -335,15 +375,43 @@ public final class TelnetInputStream extends InputStream implements SessionInfo // Telnet protocol -------------------------------------------------------- + + /** + * When true, the last read byte from the remote side was IAC. + */ + private boolean iac = false; + + /** + * When true, we are in the middle of a DO/DONT/WILL/WONT negotiation. + */ + private boolean dowill = false; + + /** + * The telnet option being negotiated. + */ + private int dowillType = 0; + + /** + * When true, we are waiting to see the end of the sub-negotiation + * sequence. + */ + private boolean subnegEnd = false; + + /** + * When true, the last byte read from the remote side was CR. + */ + private boolean readCR = false; + /** * The subnegotiation buffer. */ - private byte [] subnegBuffer; + private ArrayList subnegBuffer; /** * For debugging, return a descriptive string for this telnet option. * These are pulled from: http://www.iana.org/assignments/telnet-options * + * @param option the telnet option byte * @return a string describing the telnet option code */ private String optionString(final int option) { @@ -415,6 +483,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * * @param response a TELNET_DO/DONT/WILL/WONT byte * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void respond(final int response, final int option) throws IOException { @@ -431,6 +500,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * Tell the remote side we WILL support an option. * * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void WILL(final int option) throws IOException { respond(TELNET_WILL, option); @@ -440,6 +510,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * Tell the remote side we WON'T support an option. * * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void WONT(final int option) throws IOException { respond(TELNET_WONT, option); @@ -449,6 +520,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * Tell the remote side we DO support an option. * * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void DO(final int option) throws IOException { respond(TELNET_DO, option); @@ -458,6 +530,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * Tell the remote side we DON'T support an option. * * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void DONT(final int option) throws IOException { respond(TELNET_DONT, option); @@ -468,6 +541,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * * @param remoteQuery a TELNET_DO/DONT/WILL/WONT byte * @param option telnet option byte (binary mode, term type, etc.) + * @throws IOException if an I/O error occurs */ private void refuse(final int remoteQuery, final int option) throws IOException { @@ -480,10 +554,11 @@ public final class TelnetInputStream extends InputStream implements SessionInfo } /** - * Build sub-negotiation packet (RFC 855) + * Build sub-negotiation packet (RFC 855). * * @param option telnet option * @param response output buffer of response bytes + * @throws IOException if an I/O error occurs */ private void telnetSendSubnegResponse(final int option, final byte [] response) throws IOException { @@ -500,6 +575,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Telnet option: Terminal Speed (RFC 1079). Client side. + * + * @throws IOException if an I/O error occurs */ private void telnetSendTerminalSpeed() throws IOException { byte [] response = {0, '3', '8', '4', '0', '0', ',', @@ -509,6 +586,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Telnet option: Terminal Type (RFC 1091). Client side. + * + * @throws IOException if an I/O error occurs */ private void telnetSendTerminalType() throws IOException { byte [] response = {0, 'v', 't', '1', '0', '0' }; @@ -517,6 +596,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Telnet option: Terminal Type (RFC 1091). Server side. + * + * @throws IOException if an I/O error occurs */ private void requestTerminalType() throws IOException { byte [] response = new byte[1]; @@ -526,6 +607,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Telnet option: Terminal Speed (RFC 1079). Server side. + * + * @throws IOException if an I/O error occurs */ private void requestTerminalSpeed() throws IOException { byte [] response = new byte[1]; @@ -535,6 +618,8 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Telnet option: New Environment (RFC 1572). Server side. + * + * @throws IOException if an I/O error occurs */ private void requestEnvironment() throws IOException { byte [] response = new byte[1]; @@ -543,7 +628,12 @@ public final class TelnetInputStream extends InputStream implements SessionInfo } /** - * Send the options we want to negotiate on: + * Send the options we want to negotiate on. + * + *

The options we use are: + * + *

+ * 

      *     Binary Transmission           RFC 856
      *     Suppress Go Ahead             RFC 858
      *     Negotiate About Window Size   RFC 1073
@@ -552,70 +642,75 @@ public final class TelnetInputStream extends InputStream implements SessionInfo
      *     New Environment               RFC 1572
      *
      * When run as a server:
-     *     Echo
+     *     Echo                          RFC 857
+     *
+ * + * @throws IOException if an I/O error occurs */ void telnetSendOptions() throws IOException { - if (master.nvt.binaryMode == false) { + if (master.binaryMode == false) { // Binary Transmission: must ask both do and will DO(0); WILL(0); } - if (master.nvt.goAhead == true) { + if (master.goAhead == true) { // Suppress Go Ahead DO(3); WILL(3); } // Server only options - if (master.nvt.isServer == true) { + if (master.isServer == true) { // Enable Echo - I echo to them, they do not echo back to me. DONT(1); WILL(1); - if (master.nvt.doTermType == true) { + if (master.doTermType == true) { // Terminal type - request it DO(24); } - if (master.nvt.doTermSpeed == true) { + if (master.doTermSpeed == true) { // Terminal speed - request it DO(32); } - if (master.nvt.doNAWS == true) { + if (master.doNAWS == true) { // NAWS - request it DO(31); } - if (master.nvt.doEnvironment == true) { + if (master.doEnvironment == true) { // Environment - request it DO(39); } } else { - if (master.nvt.doTermType == true) { + if (master.doTermType == true) { // Terminal type - request it WILL(24); } - if (master.nvt.doTermSpeed == true) { + if (master.doTermSpeed == true) { // Terminal speed - request it WILL(32); } - if (master.nvt.doNAWS == true) { + if (master.doNAWS == true) { // NAWS - request it WILL(31); } - if (master.nvt.doEnvironment == true) { + if (master.doEnvironment == true) { // Environment - request it WILL(39); } - } + + // Push it all out + output.flush(); } /** @@ -633,13 +728,15 @@ public final class TelnetInputStream extends InputStream implements SessionInfo * fails to handle ESC as defined in RFC 1572. */ private void handleNewEnvironment() { - Map newEnv = new TreeMap(); + Map newEnv = + new TreeMap(); + EnvState state = EnvState.INIT; StringBuilder name = new StringBuilder(); StringBuilder value = new StringBuilder(); - for (int i = 0; i < subnegBuffer.length; i++) { - byte b = subnegBuffer[i]; + for (int i = 0; i < subnegBuffer.size(); i++) { + Byte b = subnegBuffer.get(i); switch (state) { @@ -677,7 +774,7 @@ public final class TelnetInputStream extends InputStream implements SessionInfo value = new StringBuilder(); } else { // Take it as an environment variable name/key byte - name.append((char)b); + name.append((char)b.byteValue()); } break; @@ -700,9 +797,13 @@ public final class TelnetInputStream extends InputStream implements SessionInfo name = new StringBuilder(); } else { // Take it as an environment variable value byte - value.append((char)b); + value.append((char)b.byteValue()); } break; + + default: + throw new RuntimeException("Invalid state: " + state); + } } @@ -725,80 +826,84 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Handle an option sub-negotiation. + * + * @throws IOException if an I/O error occurs */ private void handleSubneg() throws IOException { - byte option; + Byte option; // Sanity check: there must be at least 1 byte in subnegBuffer - if (subnegBuffer.length < 1) { + if (subnegBuffer.size() < 1) { // Buffer too small: the other side is a broken telnetd, it did // not send the right sub-negotiation data. Bail out now. return; } - option = subnegBuffer[0]; + option = subnegBuffer.get(0); switch (option) { case 24: // Terminal Type - if ((subnegBuffer.length > 1) && (subnegBuffer[1] == 1)) { + if ((subnegBuffer.size() > 1) && (subnegBuffer.get(1) == 1)) { // Server sent "SEND", we say "IS" telnetSendTerminalType(); } - if ((subnegBuffer.length > 1) && (subnegBuffer[1] == 0)) { + if ((subnegBuffer.size() > 1) && (subnegBuffer.get(1) == 0)) { // Client sent "IS", record it StringBuilder terminalString = new StringBuilder(); - for (int i = 2; i < subnegBuffer.length; i++) { - terminalString.append((char)subnegBuffer[i]); + for (int i = 2; i < subnegBuffer.size(); i++) { + terminalString.append((char)subnegBuffer. + get(i).byteValue()); } - master.nvt.terminal = terminalString.toString(); + master.terminalType = terminalString.toString(); } break; case 32: // Terminal Speed - if ((subnegBuffer.length > 1) && (subnegBuffer[1] == 1)) { + if ((subnegBuffer.size() > 1) && (subnegBuffer.get(1) == 1)) { // Server sent "SEND", we say "IS" telnetSendTerminalSpeed(); } - if ((subnegBuffer.length > 1) && (subnegBuffer[1] == 0)) { + if ((subnegBuffer.size() > 1) && (subnegBuffer.get(1) == 0)) { // Client sent "IS", record it StringBuilder speedString = new StringBuilder(); - for (int i = 2; i < subnegBuffer.length; i++) { - speedString.append((char)subnegBuffer[i]); + for (int i = 2; i < subnegBuffer.size(); i++) { + speedString.append((char)subnegBuffer.get(i).byteValue()); } String termSpeed = speedString.toString(); + master.terminalSpeed = speedString.toString(); } break; case 31: // NAWS - if (subnegBuffer.length >= 5) { + if (subnegBuffer.size() >= 5) { int i = 0; i++; - if (subnegBuffer[i] == TELNET_IAC) { + if (subnegBuffer.get(i) == (byte)TELNET_IAC) { i++; } - windowWidth = subnegBuffer[i] * 256; + windowWidth = subnegBuffer.get(i) * 256; i++; - if (subnegBuffer[i] == TELNET_IAC) { + if (subnegBuffer.get(i) == (byte)TELNET_IAC) { i++; } - windowWidth += subnegBuffer[i]; + windowWidth += subnegBuffer.get(i); i++; - if (subnegBuffer[i] == TELNET_IAC) { + if (subnegBuffer.get(i) == (byte)TELNET_IAC) { i++; } - windowHeight = subnegBuffer[i] * 256; + windowHeight = subnegBuffer.get(i) * 256; i++; - if (subnegBuffer[i] == TELNET_IAC) { + if (subnegBuffer.get(i) == (byte)TELNET_IAC) { i++; } - windowHeight += subnegBuffer[i]; + windowHeight += subnegBuffer.get(i); } break; @@ -816,11 +921,406 @@ public final class TelnetInputStream extends InputStream implements SessionInfo /** * Reads up to len bytes of data from the input stream into an array of * bytes. + * + * @param buf the buffer into which the data is read. + * @param off the start offset in array b at which the data is written. + * @param len the maximum number of bytes to read. + * @return the total number of bytes read into the buffer, or -1 if there + * is no more data because the end of the stream has been reached. + * @throws IOException if an I/O error occurs */ - private int readImpl(byte[] b, int off, int len) throws IOException { + private int readImpl(final byte[] buf, final int off, + final int len) throws IOException { + assert (len > 0); - // TODO - return -1; + + // The current writing position in buf. + int bufN = 0; + + // We will keep trying to read() until we have something to return. + do { + + // Read up to len bytes + byte [] buffer = new byte[len]; + int bufferN = 0; + + // Read some data from the other end + int rc = input.read(buffer); + + // Check for EOF or error + if (rc > 0) { + // More data came in + bufferN = rc; + } else { + // EOF, just return it. + return rc; + } + + // Loop through the read bytes + for (int i = 0; i < bufferN; i++) { + byte b = buffer[i]; + + if (subnegEnd == true) { + // Looking for IAC SE to end this subnegotiation + if (b == (byte)TELNET_SE) { + if (iac == true) { + iac = false; + subnegEnd = false; + handleSubneg(); + } + } else if (b == (byte)TELNET_IAC) { + if (iac == true) { + // An argument to the subnegotiation option + subnegBuffer.add((byte)TELNET_IAC); + } else { + iac = true; + } + } else { + // An argument to the subnegotiation option + subnegBuffer.add(b); + } + continue; + } + + // Look for DO/DON'T/WILL/WON'T option + if (dowill == true) { + + // Look for option/ + switch (b) { + + case 0: + // Binary Transmission + if (dowillType == (byte)TELNET_WILL) { + // Server will use binary transmission, yay. + master.binaryMode = true; + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for binary transmission. + WILL(b); + master.binaryMode = true; + } else if (dowillType == (byte)TELNET_WONT) { + // We're screwed, server won't do binary + // transmission. + master.binaryMode = false; + } else { + // Server demands NVT ASCII mode. + master.binaryMode = false; + } + break; + + case 1: + // Echo + if (dowillType == (byte)TELNET_WILL) { + // Server will use echo, yay. + master.echoMode = true; + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for echo. + WILL(b); + master.echoMode = true; + } else if (dowillType == (byte)TELNET_WONT) { + // We're screwed, server won't do echo. + master.echoMode = false; + } else { + // Server demands no echo. + master.echoMode = false; + } + break; + + case 3: + // Suppress Go Ahead + if (dowillType == (byte)TELNET_WILL) { + // Server will use suppress go-ahead, yay. + master.goAhead = false; + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for suppress go-ahead. + WILL(b); + master.goAhead = false; + } else if (dowillType == (byte)TELNET_WONT) { + // We're screwed, server won't do suppress + // go-ahead. + master.goAhead = true; + } else { + // Server demands Go-Ahead mode. + master.goAhead = true; + } + break; + + case 24: + // Terminal Type - send what's in TERM + if (dowillType == (byte)TELNET_WILL) { + // Server will use terminal type, yay. + if (master.isServer + && master.doTermType + ) { + requestTerminalType(); + master.doTermType = false; + } else if (!master.isServer) { + master.doTermType = true; + } + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for terminal type. + WILL(b); + master.doTermType = true; + } else if (dowillType == (byte)TELNET_WONT) { + // We're screwed, server won't do terminal type. + master.doTermType = false; + } else { + // Server will not listen to terminal type. + master.doTermType = false; + } + break; + + case 31: + // NAWS + if (dowillType == (byte)TELNET_WILL) { + // Server will use NAWS, yay. + master.doNAWS = true; + // NAWS cannot be requested by the server, it is + // only sent by the client. + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for NAWS. + WILL(b); + master.doNAWS = true; + } else if (dowillType == (byte)TELNET_WONT) { + // Server won't do NAWS. + master.doNAWS = false; + } else { + // Server will not listen to NAWS. + master.doNAWS = false; + } + break; + + case 32: + // Terminal Speed + if (dowillType == (byte)TELNET_WILL) { + // Server will use terminal speed, yay. + if (master.isServer + && master.doTermSpeed + ) { + requestTerminalSpeed(); + master.doTermSpeed = false; + } else if (!master.isServer) { + master.doTermSpeed = true; + } + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for terminal speed. + WILL(b); + master.doTermSpeed = true; + } else if (dowillType == (byte)TELNET_WONT) { + // We're screwed, server won't do terminal speed. + master.doTermSpeed = false; + } else { + // Server will not listen to terminal speed. + master.doTermSpeed = false; + } + break; + + case 39: + // New Environment + if (dowillType == (byte)TELNET_WILL) { + // Server will use NewEnvironment, yay. + if (master.isServer + && master.doEnvironment + ) { + requestEnvironment(); + master.doEnvironment = false; + } else if (!master.isServer) { + master.doEnvironment = true; + } + } else if (dowillType == (byte)TELNET_DO) { + // Server asks for NewEnvironment. + WILL(b); + master.doEnvironment = true; + } else if (dowillType == (byte)TELNET_WONT) { + // Server won't do NewEnvironment. + master.doEnvironment = false; + } else { + // Server will not listen to New Environment. + master.doEnvironment = false; + } + break; + + + default: + // Other side asked for something we don't + // understand. Tell them we will not do this option. + refuse(dowillType, b); + break; + } + + dowill = false; + continue; + } // if (dowill == true) + + // Perform read processing + if (b == (byte)TELNET_IAC) { + + // Telnet command + if (iac == true) { + // IAC IAC -> IAC + buf[bufN++] = (byte)TELNET_IAC; + iac = false; + } else { + iac = true; + } + continue; + } else { + if (iac == true) { + + switch (b) { + + case (byte)TELNET_SE: + // log.debug1(" END Sub-Negotiation"); + break; + case (byte)TELNET_NOP: + // log.debug1(" NOP"); + break; + case (byte)TELNET_DM: + // log.debug1(" Data Mark"); + break; + case (byte)TELNET_BRK: + // log.debug1(" Break"); + break; + case (byte)TELNET_IP: + // log.debug1(" Interrupt Process"); + break; + case (byte)TELNET_AO: + // log.debug1(" Abort Output"); + break; + case (byte)TELNET_AYT: + // log.debug1(" Are You There?"); + break; + case (byte)TELNET_EC: + // log.debug1(" Erase Character"); + break; + case (byte)TELNET_EL: + // log.debug1(" Erase Line"); + break; + case (byte)TELNET_GA: + // log.debug1(" Go Ahead"); + break; + case (byte)TELNET_SB: + // log.debug1(" START Sub-Negotiation"); + // From here we wait for the IAC SE + subnegEnd = true; + subnegBuffer.clear(); + break; + case (byte)TELNET_WILL: + // log.debug1(" WILL"); + dowill = true; + dowillType = b; + break; + case (byte)TELNET_WONT: + // log.debug1(" WON'T"); + dowill = true; + dowillType = b; + break; + case (byte)TELNET_DO: + // log.debug1(" DO"); + dowill = true; + dowillType = b; + + if (master.binaryMode == true) { + // log.debug1("Telnet DO in binary mode"); + } + + break; + case (byte)TELNET_DONT: + // log.debug1(" DON'T"); + dowill = true; + dowillType = b; + break; + default: + // This should be equivalent to IAC NOP + // log.debug1("Will treat as IAC NOP"); + break; + } + iac = false; + continue; + + } // if (iac == true) + + /* + * All of the regular IAC processing is completed at this + * point. Now we need to handle the CR and CR LF cases. + * + * According to RFC 854, in NVT ASCII mode: + * Bare CR -> CR NUL + * CR LF -> CR LF + * + */ + if (master.binaryMode == false) { + + if (b == C_LF) { + if (readCR == true) { + // This is CR LF. Send CR LF and turn the cr + // flag off. + buf[bufN++] = C_CR; + buf[bufN++] = C_LF; + readCR = false; + continue; + } + // This is bare LF. Send LF. + buf[bufN++] = C_LF; + continue; + } + + if (b == C_NUL) { + if (readCR == true) { + // This is CR NUL. Send CR and turn the cr + // flag off. + buf[bufN++] = C_CR; + readCR = false; + continue; + } + // This is bare NUL. Send NUL. + buf[bufN++] = C_NUL; + continue; + } + + if (b == C_CR) { + if (readCR == true) { + // This is CR CR. Send a CR NUL and leave + // the cr flag on. + buf[bufN++] = C_CR; + buf[bufN++] = C_NUL; + continue; + } + // This is the first CR. Set the cr flag. + readCR = true; + continue; + } + + if (readCR == true) { + // This was a bare CR in the stream. + buf[bufN++] = C_CR; + readCR = false; + } + + // This is a regular character. Pass it on. + buf[bufN++] = b; + continue; + } + + /* + * This is the case for any of: + * + * 1) A NVT ASCII character that isn't CR, LF, or + * NUL. + * + * 2) A NVT binary character. + * + * For all of these cases, we just pass the character on. + */ + buf[bufN++] = b; + + } // if (b == TELNET_IAC) + + } // for (int i = 0; i < bufferN; i++) + + } while (bufN == 0); + + // Return bytes read + return bufN; }