Been meaning to do this for years: introduce a configuration option

[u/mdw/putty] / telnet.c

diff --git a/telnet.c b/telnet.c
index 8b2c428..ed685f1 100644 (file)
--- a/telnet.c
+++ b/telnet.c
@@ -1,3 +1,7 @@
+/*
+ * Telnet backend.
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -196,12 +200,10 @@ static const struct Opt o_tspeed =
     { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
 static const struct Opt o_ttype =
     { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
-static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
-    OPTINDEX_OENV, INACTIVE
-};
-static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
-    OPTINDEX_NENV, REQUESTED
-};
+static const struct Opt o_oenv =
+    { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
+static const struct Opt o_nenv =
+    { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
 static const struct Opt o_echo =
     { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
 static const struct Opt o_we_sga =
@@ -252,11 +254,10 @@ typedef struct telnet_tag {
 
 #define SB_DELTA 1024
 
-static void c_write1(Telnet telnet, int c)
+static void c_write(Telnet telnet, char *buf, int len)
 {
     int backlog;
-    char cc = (char) c;
-    backlog = from_backend(telnet->frontend, 0, &cc, 1);
+    backlog = from_backend(telnet->frontend, 0, buf, len);
     sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
 }
 
@@ -396,9 +397,12 @@ static void proc_rec_opt(Telnet telnet, int cmd, int option)
     }
     /*
      * If we reach here, the option was one we weren't prepared to
-     * cope with. So send a negative ack.
+     * 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.
      */
-    send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
+    if (cmd == WILL || cmd == DO)
+        send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
 }
 
 static void process_subneg(Telnet telnet)
@@ -536,6 +540,16 @@ static void process_subneg(Telnet telnet)
 
 static void do_telnet_read(Telnet telnet, char *buf, int len)
 {
+    char *outbuf = NULL;
+    int outbuflen = 0, outbufsize = 0;
+
+#define ADDTOBUF(c) do { \
+    if (outbuflen >= outbufsize) { \
+       outbufsize = outbuflen + 256; \
+        outbuf = sresize(outbuf, outbufsize, char); \
+    } \
+    outbuf[outbuflen++] = (c); \
+} while (0)
 
     while (len--) {
        int c = (unsigned char) *buf++;
@@ -549,7 +563,7 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
                telnet->state = SEENIAC;
            else {
                if (!telnet->in_synch)
-                   c_write1(telnet, c);
+                   ADDTOBUF(c);
 
 #if 1
                /* I can't get the F***ing winsock to insert the urgent IAC
@@ -586,7 +600,7 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
            } else {
                /* ignore everything else; print it if it's IAC */
                if (c == IAC) {
-                   c_write1(telnet, c);
+                   ADDTOBUF(c);
                }
                telnet->state = TOP_LEVEL;
            }
@@ -636,6 +650,26 @@ static void do_telnet_read(Telnet telnet, char *buf, int len)
            break;
        }
     }
+
+    if (outbuflen)
+       c_write(telnet, outbuf, outbuflen);
+    sfree(outbuf);
+}
+
+static void telnet_log(Plug plug, int type, SockAddr addr, int port,
+                      const char *error_msg, int error_code)
+{
+    Telnet telnet = (Telnet) plug;
+    char addrbuf[256], *msg;
+
+    sk_getaddr(addr, addrbuf, lenof(addrbuf));
+
+    if (type == 0)
+       msg = dupprintf("Connecting to %s port %d", addrbuf, port);
+    else
+       msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
+
+    logevent(telnet->frontend, msg);
 }
 
 static int telnet_closing(Plug plug, const char *error_msg, int error_code,
@@ -649,10 +683,10 @@ static int telnet_closing(Plug plug, const char *error_msg, int error_code,
        notify_remote_exit(telnet->frontend);
     }
     if (error_msg) {
-       /* A socket error has occurred. */
        logevent(telnet->frontend, error_msg);
        connection_fatal(telnet->frontend, "%s", error_msg);
-    }                                 /* Otherwise, the remote side closed the connection normally. */
+    }
+    /* Otherwise, the remote side closed the connection normally. */
     return 0;
 }
 
@@ -685,6 +719,7 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
                               int nodelay, int keepalive)
 {
     static const struct plug_function_table fn_table = {
+       telnet_log,
        telnet_closing,
        telnet_receive,
        telnet_sent
@@ -715,11 +750,14 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
      */
     {
        char *buf;
-       buf = dupprintf("Looking up host \"%s\"", host);
+       buf = dupprintf("Looking up host \"%s\"%s", host,
+                       (cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
+                        (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
+                         "")));
        logevent(telnet->frontend, buf);
        sfree(buf);
     }
-    addr = name_lookup(host, port, realhost, &telnet->cfg);
+    addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);
     if ((err = sk_addr_error(addr)) != NULL) {
        sk_addr_free(addr);
        return err;
@@ -731,13 +769,6 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
     /*
      * Open socket.
      */
-    {
-       char *buf, addrbuf[100];
-       sk_getaddr(addr, addrbuf, 100);
-       buf = dupprintf("Connecting to %s port %d", addrbuf, port);
-       logevent(telnet->frontend, buf);
-       sfree(buf);
-    }
     telnet->s = new_connection(addr, *realhost, port, 0, 1,
                               nodelay, keepalive, (Plug) telnet, &telnet->cfg);
     if ((err = sk_socket_error(telnet->s)) != NULL)
@@ -774,6 +805,25 @@ static const char *telnet_init(void *frontend_handle, void **backend_handle,
      */
     update_specials_menu(telnet->frontend);
 
+    /*
+     * loghost overrides realhost, if specified.
+     */
+    if (*telnet->cfg.loghost) {
+       char *colon;
+
+       sfree(*realhost);
+       *realhost = dupstr(telnet->cfg.loghost);
+       colon = strrchr(*realhost, ':');
+       if (colon) {
+           /*
+            * FIXME: if we ever update this aspect of ssh.c for
+            * IPv6 literal management, this should change in line
+            * with it.
+            */
+           *colon++ = '\0';
+       }
+    }
+
     return NULL;
 }
 
@@ -1001,10 +1051,10 @@ static const struct telnet_special *telnet_get_specials(void *handle)
     return specials;
 }
 
-static Socket telnet_socket(void *handle)
+static int telnet_connected(void *handle)
 {
     Telnet telnet = (Telnet) handle;
-    return telnet->s;
+    return telnet->s != NULL;
 }
 
 static int telnet_sendok(void *handle)
@@ -1050,6 +1100,14 @@ static int telnet_exitcode(void *handle)
         return 0;
 }
 
+/*
+ * cfg_info for Telnet does nothing at all.
+ */
+static int telnet_cfg_info(void *handle)
+{
+    return 0;
+}
+
 Backend telnet_backend = {
     telnet_init,
     telnet_free,
@@ -1059,12 +1117,15 @@ Backend telnet_backend = {
     telnet_size,
     telnet_special,
     telnet_get_specials,
-    telnet_socket,
+    telnet_connected,
     telnet_exitcode,
     telnet_sendok,
     telnet_ldisc,
     telnet_provide_ldisc,
     telnet_provide_logctx,
     telnet_unthrottle,
+    telnet_cfg_info,
+    "telnet",
+    PROT_TELNET,
     23
 };