--- /dev/null
+/*
+ * Simple Telnet server code, adapted from PuTTY's own Telnet
+ * client code for use as a Cygwin local pty proxy.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sel.h"
+#include "telnet.h"
+#include "malloc.h"
+#include "pty.h"
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#define IAC 255 /* interpret as command: */
+#define DONT 254 /* you are not to use option */
+#define DO 253 /* please, you use option */
+#define WONT 252 /* I won't use option */
+#define WILL 251 /* I will use option */
+#define SB 250 /* interpret as subnegotiation */
+#define SE 240 /* end sub negotiation */
+
+#define GA 249 /* you may reverse the line */
+#define EL 248 /* erase the current line */
+#define EC 247 /* erase the current character */
+#define AYT 246 /* are you there */
+#define AO 245 /* abort output--but let prog finish */
+#define IP 244 /* interrupt process--permanently */
+#define BREAK 243 /* break */
+#define DM 242 /* data mark--for connect. cleaning */
+#define NOP 241 /* nop */
+#define EOR 239 /* end of record (transparent mode) */
+#define ABORT 238 /* Abort process */
+#define SUSP 237 /* Suspend process */
+#define xEOF 236 /* End of file: EOF is already used... */
+
+#define TELOPTS(X) \
+ X(BINARY, 0) /* 8-bit data path */ \
+ X(ECHO, 1) /* echo */ \
+ X(RCP, 2) /* prepare to reconnect */ \
+ X(SGA, 3) /* suppress go ahead */ \
+ X(NAMS, 4) /* approximate message size */ \
+ X(STATUS, 5) /* give status */ \
+ X(TM, 6) /* timing mark */ \
+ X(RCTE, 7) /* remote controlled transmission and echo */ \
+ X(NAOL, 8) /* negotiate about output line width */ \
+ X(NAOP, 9) /* negotiate about output page size */ \
+ X(NAOCRD, 10) /* negotiate about CR disposition */ \
+ X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \
+ X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \
+ X(NAOFFD, 13) /* negotiate about formfeed disposition */ \
+ X(NAOVTS, 14) /* negotiate about vertical tab stops */ \
+ X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \
+ X(NAOLFD, 16) /* negotiate about output LF disposition */ \
+ X(XASCII, 17) /* extended ascic character set */ \
+ X(LOGOUT, 18) /* force logout */ \
+ X(BM, 19) /* byte macro */ \
+ X(DET, 20) /* data entry terminal */ \
+ X(SUPDUP, 21) /* supdup protocol */ \
+ X(SUPDUPOUTPUT, 22) /* supdup output */ \
+ X(SNDLOC, 23) /* send location */ \
+ X(TTYPE, 24) /* terminal type */ \
+ X(EOR, 25) /* end or record */ \
+ X(TUID, 26) /* TACACS user identification */ \
+ X(OUTMRK, 27) /* output marking */ \
+ X(TTYLOC, 28) /* terminal location number */ \
+ X(3270REGIME, 29) /* 3270 regime */ \
+ X(X3PAD, 30) /* X.3 PAD */ \
+ X(NAWS, 31) /* window size */ \
+ X(TSPEED, 32) /* terminal speed */ \
+ X(LFLOW, 33) /* remote flow control */ \
+ X(LINEMODE, 34) /* Linemode option */ \
+ X(XDISPLOC, 35) /* X Display Location */ \
+ X(OLD_ENVIRON, 36) /* Old - Environment variables */ \
+ X(AUTHENTICATION, 37) /* Authenticate */ \
+ X(ENCRYPT, 38) /* Encryption option */ \
+ X(NEW_ENVIRON, 39) /* New - Environment variables */ \
+ X(TN3270E, 40) /* TN3270 enhancements */ \
+ X(XAUTH, 41) \
+ X(CHARSET, 42) /* Character set */ \
+ X(RSP, 43) /* Remote serial port */ \
+ X(COM_PORT_OPTION, 44) /* Com port control */ \
+ X(SLE, 45) /* Suppress local echo */ \
+ X(STARTTLS, 46) /* Start TLS */ \
+ X(KERMIT, 47) /* Automatic Kermit file transfer */ \
+ X(SEND_URL, 48) \
+ X(FORWARD_X, 49) \
+ X(PRAGMA_LOGON, 138) \
+ X(SSPI_LOGON, 139) \
+ X(PRAGMA_HEARTBEAT, 140) \
+ X(EXOPL, 255) /* extended-options-list */
+
+#define telnet_enum(x,y) TELOPT_##x = y,
+enum { TELOPTS(telnet_enum) dummy=0 };
+#undef telnet_enum
+
+#define TELQUAL_IS 0 /* option is... */
+#define TELQUAL_SEND 1 /* send option */
+#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
+#define BSD_VAR 1
+#define BSD_VALUE 0
+#define RFC_VAR 0
+#define RFC_VALUE 1
+
+#define CR 13
+#define LF 10
+#define NUL 0
+
+#define iswritable(x) ( (x) != IAC && (x) != CR )
+
+static char *telopt(int opt)
+{
+#define telnet_str(x,y) case TELOPT_##x: return #x;
+ switch (opt) {
+ TELOPTS(telnet_str)
+ default:
+ return "<unknown>";
+ }
+#undef telnet_str
+}
+
+static void telnet_size(void *handle, int width, int height);
+
+struct Opt {
+ int send; /* what we initially send */
+ int nsend; /* -ve send if requested to stop it */
+ int ack, nak; /* +ve and -ve acknowledgements */
+ int option; /* the option code */
+ int index; /* index into telnet->opt_states[] */
+ enum {
+ REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
+ } initial_state;
+};
+
+enum {
+ OPTINDEX_NAWS,
+ OPTINDEX_TSPEED,
+ OPTINDEX_TTYPE,
+ OPTINDEX_OENV,
+ OPTINDEX_NENV,
+ OPTINDEX_ECHO,
+ OPTINDEX_WE_SGA,
+ OPTINDEX_THEY_SGA,
+ OPTINDEX_WE_BIN,
+ OPTINDEX_THEY_BIN,
+ NUM_OPTS
+};
+
+static const struct Opt o_naws =
+ { DO, DONT, WILL, WONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
+static const struct Opt o_ttype =
+ { DO, DONT, WILL, WONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
+static const struct Opt o_oenv =
+ { DO, DONT, WILL, WONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
+static const struct Opt o_nenv =
+ { DO, DONT, WILL, WONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
+static const struct Opt o_echo =
+ { WILL, WONT, DO, DONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
+static const struct Opt o_they_sga =
+ { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
+static const struct Opt o_we_sga =
+ { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
+
+static const struct Opt *const opts[] = {
+ &o_echo, &o_we_sga, &o_they_sga, &o_naws, &o_ttype, &o_oenv, &o_nenv, NULL
+};
+
+struct telnet_tag {
+ int opt_states[NUM_OPTS];
+
+ int sb_opt, sb_len;
+ unsigned char *sb_buf;
+ int sb_size;
+
+ enum {
+ TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
+ SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
+ } state;
+
+ sel_wfd *net, *pty;
+
+ /*
+ * Options we must finish processing before launching the shell
+ */
+ int old_environ_done, new_environ_done, ttype_done;
+
+ /*
+ * Ready to start shell?
+ */
+ int shell_ok;
+ int envvarsize;
+ struct shell_data shdata;
+};
+
+#define TELNET_MAX_BACKLOG 4096
+
+#define SB_DELTA 1024
+
+static void send_opt(Telnet telnet, int cmd, int option)
+{
+ unsigned char b[3];
+
+ b[0] = IAC;
+ b[1] = cmd;
+ b[2] = option;
+ sel_write(telnet->net, (char *)b, 3);
+}
+
+static void deactivate_option(Telnet telnet, const struct Opt *o)
+{
+ if (telnet->opt_states[o->index] == REQUESTED ||
+ telnet->opt_states[o->index] == ACTIVE)
+ send_opt(telnet, o->nsend, o->option);
+ telnet->opt_states[o->index] = REALLY_INACTIVE;
+}
+
+/*
+ * Generate side effects of enabling or disabling an option.
+ */
+static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
+{
+}
+
+static void activate_option(Telnet telnet, const struct Opt *o)
+{
+ if (o->option == TELOPT_NEW_ENVIRON ||
+ o->option == TELOPT_OLD_ENVIRON ||
+ o->option == TELOPT_TTYPE) {
+ char buf[6];
+ buf[0] = IAC;
+ buf[1] = SB;
+ buf[2] = o->option;
+ buf[3] = TELQUAL_SEND;
+ buf[4] = IAC;
+ buf[5] = SE;
+ sel_write(telnet->net, buf, 6);
+ }
+ option_side_effects(telnet, o, 1);
+}
+
+static void done_option(Telnet telnet, int option)
+{
+ if (option == TELOPT_OLD_ENVIRON)
+ telnet->old_environ_done = 1;
+ else if (option == TELOPT_NEW_ENVIRON)
+ telnet->new_environ_done = 1;
+ else if (option == TELOPT_TTYPE)
+ telnet->ttype_done = 1;
+
+ if (telnet->old_environ_done && telnet->new_environ_done &&
+ telnet->ttype_done) {
+ telnet->shell_ok = 1;
+ }
+}
+
+static void refused_option(Telnet telnet, const struct Opt *o)
+{
+ done_option(telnet, o->option);
+ if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
+ telnet->opt_states[o_oenv.index] == INACTIVE) {
+ send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
+ telnet->opt_states[o_oenv.index] = REQUESTED;
+ telnet->old_environ_done = 0;
+ }
+ option_side_effects(telnet, o, 0);
+}
+
+static void proc_rec_opt(Telnet telnet, int cmd, int option)
+{
+ const struct Opt *const *o;
+
+ for (o = opts; *o; o++) {
+ if ((*o)->option == option && (*o)->ack == cmd) {
+ switch (telnet->opt_states[(*o)->index]) {
+ case REQUESTED:
+ telnet->opt_states[(*o)->index] = ACTIVE;
+ activate_option(telnet, *o);
+ break;
+ case ACTIVE:
+ break;
+ case INACTIVE:
+ telnet->opt_states[(*o)->index] = ACTIVE;
+ send_opt(telnet, (*o)->send, option);
+ activate_option(telnet, *o);
+ break;
+ case REALLY_INACTIVE:
+ send_opt(telnet, (*o)->nsend, option);
+ break;
+ }
+ return;
+ } else if ((*o)->option == option && (*o)->nak == cmd) {
+ switch (telnet->opt_states[(*o)->index]) {
+ case REQUESTED:
+ telnet->opt_states[(*o)->index] = INACTIVE;
+ refused_option(telnet, *o);
+ break;
+ case ACTIVE:
+ telnet->opt_states[(*o)->index] = INACTIVE;
+ send_opt(telnet, (*o)->nsend, option);
+ option_side_effects(telnet, *o, 0);
+ break;
+ case INACTIVE:
+ case REALLY_INACTIVE:
+ break;
+ }
+ return;
+ }
+ }
+ /*
+ * If we reach here, the option was one we weren't prepared to
+ * cope with. If the request was positive (WILL or DO), we send
+ * a negative ack to indicate refusal. If the request was
+ * negative (WONT / DONT), we must do nothing.
+ */
+ if (cmd == WILL || cmd == DO)
+ send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
+}
+
+static void process_subneg(Telnet telnet)
+{
+ unsigned char b[2048], *p, *q;
+ int var, value, n;
+ char *e;
+
+ switch (telnet->sb_opt) {
+ case TELOPT_OLD_ENVIRON:
+ case TELOPT_NEW_ENVIRON:
+ if (telnet->sb_buf[0] == TELQUAL_IS) {
+ if (telnet->sb_opt == TELOPT_NEW_ENVIRON) {
+ var = RFC_VAR;
+ value = RFC_VALUE;
+ } else {
+ if (telnet->sb_len > 1 && !(telnet->sb_buf[0] &~ 1)) {
+ var = telnet->sb_buf[0];
+ value = BSD_VAR ^ BSD_VALUE ^ var;
+ } else {
+ var = BSD_VAR;
+ value = BSD_VALUE;
+ }
+ }
+ }
+ n = 1;
+ while (n < telnet->sb_len && telnet->sb_buf[n] == var) {
+ int varpos, varlen, valpos, vallen;
+ char *result;
+
+ varpos = ++n;
+ while (n < telnet->sb_len && telnet->sb_buf[n] != value)
+ n++;
+ if (n == telnet->sb_len)
+ break;
+ varlen = n - varpos;
+ valpos = ++n;
+ while (n < telnet->sb_len && telnet->sb_buf[n] != var)
+ n++;
+ vallen = n - valpos;
+
+ result = snewn(varlen + vallen + 2, char);
+ sprintf(result, "%.*s=%.*s",
+ varlen, telnet->sb_buf+varpos,
+ vallen, telnet->sb_buf+valpos);
+ if (telnet->shdata.nenvvars >= telnet->envvarsize) {
+ telnet->envvarsize = telnet->shdata.nenvvars * 3 / 2 + 16;
+ telnet->shdata.envvars = sresize(telnet->shdata.envvars,
+ telnet->envvarsize, char *);
+ }
+ telnet->shdata.envvars[telnet->shdata.nenvvars++] = result;
+ }
+ done_option(telnet, telnet->sb_opt);
+ break;
+ case TELOPT_TTYPE:
+ if (telnet->sb_len >= 1 && telnet->sb_buf[0] == TELQUAL_IS) {
+ telnet->shdata.termtype = snewn(5 + telnet->sb_len, char);
+ strcpy(telnet->shdata.termtype, "TERM=");
+ for (n = 0; n < telnet->sb_len-1; n++) {
+ char c = telnet->sb_buf[n+1];
+ if (c >= 'A' && c <= 'Z')
+ c = c + 'a' - 'A';
+ telnet->shdata.termtype[n+5] = c;
+ }
+ telnet->shdata.termtype[telnet->sb_len+5-1] = '\0';
+ }
+ done_option(telnet, telnet->sb_opt);
+ break;
+ case TELOPT_NAWS:
+ if (telnet->sb_len == 4) {
+ int w, h;
+ w = (unsigned char)telnet->sb_buf[0];
+ w = (w << 8) | (unsigned char)telnet->sb_buf[1];
+ h = (unsigned char)telnet->sb_buf[2];
+ h = (h << 8) | (unsigned char)telnet->sb_buf[3];
+ pty_resize(w, h);
+ }
+ break;
+ }
+}
+
+void telnet_from_net(Telnet telnet, char *buf, int len)
+{
+ while (len--) {
+ int c = (unsigned char) *buf++;
+
+ switch (telnet->state) {
+ case TOP_LEVEL:
+ case SEENCR:
+ /*
+ * PuTTY sends Telnet's new line sequence (CR LF on
+ * the wire) in response to the return key. We must
+ * therefore treat that as equivalent to CR NUL, and
+ * send CR to the pty.
+ */
+ if ((c == NUL || c == '\n') && telnet->state == SEENCR)
+ telnet->state = TOP_LEVEL;
+ else if (c == IAC)
+ telnet->state = SEENIAC;
+ else {
+ char cc = c;
+ sel_write(telnet->pty, &cc, 1);
+
+ telnet->state = SEENCR;
+ }
+ break;
+ case SEENIAC:
+ if (c == DO)
+ telnet->state = SEENDO;
+ else if (c == DONT)
+ telnet->state = SEENDONT;
+ else if (c == WILL)
+ telnet->state = SEENWILL;
+ else if (c == WONT)
+ telnet->state = SEENWONT;
+ else if (c == SB)
+ telnet->state = SEENSB;
+ else if (c == DM)
+ telnet->state = TOP_LEVEL;
+ else {
+ /* ignore everything else; print it if it's IAC */
+ if (c == IAC) {
+ char cc = c;
+ sel_write(telnet->pty, &cc, 1);
+ }
+ telnet->state = TOP_LEVEL;
+ }
+ break;
+ case SEENWILL:
+ proc_rec_opt(telnet, WILL, c);
+ telnet->state = TOP_LEVEL;
+ break;
+ case SEENWONT:
+ proc_rec_opt(telnet, WONT, c);
+ telnet->state = TOP_LEVEL;
+ break;
+ case SEENDO:
+ proc_rec_opt(telnet, DO, c);
+ telnet->state = TOP_LEVEL;
+ break;
+ case SEENDONT:
+ proc_rec_opt(telnet, DONT, c);
+ telnet->state = TOP_LEVEL;
+ break;
+ case SEENSB:
+ telnet->sb_opt = c;
+ telnet->sb_len = 0;
+ telnet->state = SUBNEGOT;
+ break;
+ case SUBNEGOT:
+ if (c == IAC)
+ telnet->state = SUBNEG_IAC;
+ else {
+ subneg_addchar:
+ if (telnet->sb_len >= telnet->sb_size) {
+ telnet->sb_size += SB_DELTA;
+ telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
+ unsigned char);
+ }
+ telnet->sb_buf[telnet->sb_len++] = c;
+ telnet->state = SUBNEGOT; /* in case we came here by goto */
+ }
+ break;
+ case SUBNEG_IAC:
+ if (c != SE)
+ goto subneg_addchar; /* yes, it's a hack, I know, but... */
+ else {
+ process_subneg(telnet);
+ telnet->state = TOP_LEVEL;
+ }
+ break;
+ }
+ }
+}
+
+Telnet telnet_new(sel_wfd *net, sel_wfd *pty)
+{
+ Telnet telnet;
+
+ telnet = snew(struct telnet_tag);
+ telnet->sb_buf = NULL;
+ telnet->sb_size = 0;
+ telnet->state = TOP_LEVEL;
+ telnet->net = net;
+ telnet->pty = pty;
+ telnet->shdata.envvars = NULL;
+ telnet->shdata.nenvvars = telnet->envvarsize = 0;
+ telnet->shdata.termtype = NULL;
+
+ /*
+ * Initialise option states.
+ */
+ {
+ const struct Opt *const *o;
+
+ for (o = opts; *o; o++) {
+ telnet->opt_states[(*o)->index] = (*o)->initial_state;
+ if (telnet->opt_states[(*o)->index] == REQUESTED)
+ send_opt(telnet, (*o)->send, (*o)->option);
+ }
+ }
+
+ telnet->old_environ_done = 1; /* initially don't want to bother */
+ telnet->new_environ_done = 0;
+ telnet->ttype_done = 0;
+ telnet->shell_ok = 0;
+
+ return telnet;
+}
+
+void telnet_free(Telnet telnet)
+{
+ sfree(telnet->sb_buf);
+ sfree(telnet);
+}
+
+void telnet_from_pty(Telnet telnet, char *buf, int len)
+{
+ unsigned char *p, *end;
+ static const unsigned char iac[2] = { IAC, IAC };
+ static const unsigned char cr[2] = { CR, NUL };
+#if 0
+ static const unsigned char nl[2] = { CR, LF };
+#endif
+
+ p = (unsigned char *)buf;
+ end = (unsigned char *)(buf + len);
+ while (p < end) {
+ unsigned char *q = p;
+
+ while (p < end && iswritable(*p))
+ p++;
+ sel_write(telnet->net, (char *)q, p - q);
+
+ while (p < end && !iswritable(*p)) {
+ sel_write(telnet->net, (char *)(*p == IAC ? iac : cr), 2);
+ p++;
+ }
+ }
+}
+
+int telnet_shell_ok(Telnet telnet, struct shell_data *shdata)
+{
+ if (telnet->shell_ok)
+ *shdata = telnet->shdata; /* structure copy */
+ return telnet->shell_ok;
+}
~mdw / sgt / putty / blobdiff