X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/7ffdbc1adcc37edecd9737e9b59de3d73b2e7901..HEAD:/proxy.c

diff --git a/proxy.c b/proxy.c
index 2ea0bc8c..8a146231 100644
--- a/proxy.c
+++ b/proxy.c
@@ -14,9 +14,10 @@
 #include "network.h"
 #include "proxy.h"
 
-#define do_proxy_dns(cfg) \
-    (cfg->proxy_dns == FORCE_ON || \
-	 (cfg->proxy_dns == AUTO && cfg->proxy_type != PROXY_SOCKS))
+#define do_proxy_dns(conf) \
+    (conf_get_int(conf, CONF_proxy_dns) == FORCE_ON || \
+	 (conf_get_int(conf, CONF_proxy_dns) == AUTO && \
+	      conf_get_int(conf, CONF_proxy_type) != PROXY_SOCKS4))
 
 /*
  * Call this when proxy negotiation is complete, so that this
@@ -64,6 +65,9 @@ void proxy_activate (Proxy_Socket p)
      */
     if (p->pending_flush) sk_flush(p->sub_socket);
 
+    /* if we have a pending EOF to send, send it */
+    if (p->pending_eof) sk_write_eof(p->sub_socket);
+
     /* if the backend wanted the socket unfrozen, try to unfreeze.
      * our set_frozen handler will flush buffered receive data before
      * unfreezing the actual underlying socket.
@@ -88,6 +92,7 @@ static void sk_proxy_close (Socket s)
     Proxy_Socket ps = (Proxy_Socket) s;
 
     sk_close(ps->sub_socket);
+    sk_addr_free(ps->remote_addr);
     sfree(ps);
 }
 
@@ -115,6 +120,17 @@ static int sk_proxy_write_oob (Socket s, const char *data, int len)
     return sk_write_oob(ps->sub_socket, data, len);
 }
 
+static void sk_proxy_write_eof (Socket s)
+{
+    Proxy_Socket ps = (Proxy_Socket) s;
+
+    if (ps->state != PROXY_STATE_ACTIVE) {
+        ps->pending_eof = 1;
+	return;
+    }
+    sk_write_eof(ps->sub_socket);
+}
+
 static void sk_proxy_flush (Socket s)
 {
     Proxy_Socket ps = (Proxy_Socket) s;
@@ -158,10 +174,14 @@ static void sk_proxy_set_frozen (Socket s, int is_frozen)
 	 */
         while (!ps->freeze && bufchain_size(&ps->pending_input_data) > 0) {
 	    void *data;
+	    char databuf[512];
 	    int len;
 	    bufchain_prefix(&ps->pending_input_data, &data, &len);
-	    plug_receive(ps->plug, 0, data, len);
+	    if (len > lenof(databuf))
+		len = lenof(databuf);
+	    memcpy(databuf, data, len);
 	    bufchain_consume(&ps->pending_input_data, len);
+	    plug_receive(ps->plug, 0, databuf, len);
 	}
 
 	/* if we're still frozen, we'll have to wait for another
@@ -173,7 +193,7 @@ static void sk_proxy_set_frozen (Socket s, int is_frozen)
     sk_set_frozen(ps->sub_socket, is_frozen);
 }
 
-static char * sk_proxy_socket_error (Socket s)
+static const char * sk_proxy_socket_error (Socket s)
 {
     Proxy_Socket ps = (Proxy_Socket) s;
     if (ps->error != NULL || ps->sub_socket == NULL) {
@@ -184,7 +204,16 @@ static char * sk_proxy_socket_error (Socket s)
 
 /* basic proxy plug functions */
 
-static int plug_proxy_closing (Plug p, char *error_msg,
+static void plug_proxy_log(Plug plug, int type, SockAddr addr, int port,
+			   const char *error_msg, int error_code)
+{
+    Proxy_Plug pp = (Proxy_Plug) plug;
+    Proxy_Socket ps = pp->proxy_socket;
+
+    plug_log(ps->plug, type, addr, port, error_msg, error_code);
+}
+
+static int plug_proxy_closing (Plug p, const char *error_msg,
 			       int error_code, int calling_back)
 {
     Proxy_Plug pp = (Proxy_Plug) p;
@@ -232,7 +261,7 @@ static void plug_proxy_sent (Plug p, int bufsize)
     plug_sent(ps->plug, bufsize);
 }
 
-static int plug_proxy_accepting (Plug p, void *sock)
+static int plug_proxy_accepting (Plug p, OSSocket sock)
 {
     Proxy_Plug pp = (Proxy_Plug) p;
     Proxy_Socket ps = pp->proxy_socket;
@@ -248,8 +277,8 @@ static int plug_proxy_accepting (Plug p, void *sock)
  * This function can accept a NULL pointer as `addr', in which case
  * it will only check the host name.
  */
-static int proxy_for_destination (SockAddr addr, char *hostname, int port,
-				  const Config *cfg)
+static int proxy_for_destination (SockAddr addr, const char *hostname,
+                                  int port, Conf *conf)
 {
     int s = 0, e = 0;
     char hostip[64];
@@ -257,10 +286,19 @@ static int proxy_for_destination (SockAddr addr, char *hostname, int port,
     const char *exclude_list;
 
     /*
+     * Special local connections such as Unix-domain sockets
+     * unconditionally cannot be proxied, even in proxy-localhost
+     * mode. There just isn't any way to ask any known proxy type for
+     * them.
+     */
+    if (addr && sk_address_is_special_local(addr))
+        return 0;                      /* do not proxy */
+
+    /*
      * Check the host name and IP against the hard-coded
      * representations of `localhost'.
      */
-    if (!cfg->even_proxy_localhost &&
+    if (!conf_get_int(conf, CONF_even_proxy_localhost) &&
 	(sk_hostname_is_local(hostname) ||
 	 (addr && sk_address_is_local(addr))))
 	return 0;		       /* do not proxy */
@@ -274,7 +312,7 @@ static int proxy_for_destination (SockAddr addr, char *hostname, int port,
 
     hostname_len = strlen(hostname);
 
-    exclude_list = cfg->proxy_exclude_list;
+    exclude_list = conf_get_str(conf, CONF_proxy_exclude_list);
 
     /* now parse the exclude list, and see if either our IP
      * or hostname matches anything in it.
@@ -316,9 +354,9 @@ static int proxy_for_destination (SockAddr addr, char *hostname, int port,
 	     * match (ie. a specific IP)
 	     */
 
-	    if (addr && stricmp(hostip, exclude_list + s) == 0)
+	    if (addr && strnicmp(hostip, exclude_list + s, e - s) == 0)
 		return 0; /* IP/hostname excluded. do not use proxy. */
-	    if (stricmp(hostname, exclude_list + s) == 0)
+	    if (strnicmp(hostname, exclude_list + s, e - s) == 0)
 		return 0; /* IP/hostname excluded. do not use proxy. */
 	}
 
@@ -335,28 +373,29 @@ static int proxy_for_destination (SockAddr addr, char *hostname, int port,
 }
 
 SockAddr name_lookup(char *host, int port, char **canonicalname,
-		     const Config *cfg)
+		     Conf *conf, int addressfamily)
 {
-    if (cfg->proxy_type != PROXY_NONE &&
-	do_proxy_dns(cfg) &&
-	proxy_for_destination(NULL, host, port, cfg)) {
+    if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
+	do_proxy_dns(conf) &&
+	proxy_for_destination(NULL, host, port, conf)) {
 	*canonicalname = dupstr(host);
 	return sk_nonamelookup(host);
     }
 
-    return sk_namelookup(host, canonicalname);
+    return sk_namelookup(host, canonicalname, addressfamily);
 }
 
 Socket new_connection(SockAddr addr, char *hostname,
 		      int port, int privport,
-		      int oobinline, int nodelay, Plug plug,
-		      const Config *cfg)
+		      int oobinline, int nodelay, int keepalive,
+		      Plug plug, Conf *conf)
 {
     static const struct socket_function_table socket_fn_table = {
 	sk_proxy_plug,
 	sk_proxy_close,
 	sk_proxy_write,
 	sk_proxy_write_oob,
+	sk_proxy_write_eof,
 	sk_proxy_flush,
 	sk_proxy_set_private_ptr,
 	sk_proxy_get_private_ptr,
@@ -365,29 +404,39 @@ Socket new_connection(SockAddr addr, char *hostname,
     };
 
     static const struct plug_function_table plug_fn_table = {
+	plug_proxy_log,
 	plug_proxy_closing,
 	plug_proxy_receive,
 	plug_proxy_sent,
 	plug_proxy_accepting
     };
 
-    if (cfg->proxy_type != PROXY_NONE &&
-	proxy_for_destination(addr, hostname, port, cfg))
+    if (conf_get_int(conf, CONF_proxy_type) != PROXY_NONE &&
+	proxy_for_destination(addr, hostname, port, conf))
     {
 	Proxy_Socket ret;
 	Proxy_Plug pplug;
 	SockAddr proxy_addr;
-	char *proxy_canonical_name, *err;
+	char *proxy_canonical_name;
+	Socket sret;
+	int type;
+
+	if ((sret = platform_new_connection(addr, hostname, port, privport,
+					    oobinline, nodelay, keepalive,
+					    plug, conf)) !=
+	    NULL)
+	    return sret;
 
 	ret = snew(struct Socket_proxy_tag);
 	ret->fn = &socket_fn_table;
-	ret->cfg = *cfg;	       /* STRUCTURE COPY */
+	ret->conf = conf_copy(conf);
 	ret->plug = plug;
-	ret->remote_addr = addr;
+	ret->remote_addr = addr;       /* will need to be freed on close */
 	ret->remote_port = port;
 
 	ret->error = NULL;
 	ret->pending_flush = 0;
+	ret->pending_eof = 0;
 	ret->freeze = 0;
 
 	bufchain_init(&ret->pending_input_data);
@@ -397,15 +446,15 @@ Socket new_connection(SockAddr addr, char *hostname,
 	ret->sub_socket = NULL;
 	ret->state = PROXY_STATE_NEW;
 	ret->negotiate = NULL;
-	
-	if (cfg->proxy_type == PROXY_HTTP) {
+
+	type = conf_get_int(conf, CONF_proxy_type);
+	if (type == PROXY_HTTP) {
 	    ret->negotiate = proxy_http_negotiate;
-	} else if (cfg->proxy_type == PROXY_SOCKS) {
-	    if (cfg->proxy_socks_version == 4)
-		ret->negotiate = proxy_socks4_negotiate;
-	    else
-		ret->negotiate = proxy_socks5_negotiate;
-	} else if (cfg->proxy_type == PROXY_TELNET) {
+	} else if (type == PROXY_SOCKS4) {
+            ret->negotiate = proxy_socks4_negotiate;
+	} else if (type == PROXY_SOCKS5) {
+            ret->negotiate = proxy_socks5_negotiate;
+	} else if (type == PROXY_TELNET) {
 	    ret->negotiate = proxy_telnet_negotiate;
 	} else {
 	    ret->error = "Proxy error: Unknown proxy method";
@@ -419,10 +468,13 @@ Socket new_connection(SockAddr addr, char *hostname,
 	pplug->proxy_socket = ret;
 
 	/* look-up proxy */
-	proxy_addr = sk_namelookup(cfg->proxy_host,
-				   &proxy_canonical_name);
-	if ((err = sk_addr_error(proxy_addr)) != NULL) {
+	proxy_addr = sk_namelookup(conf_get_str(conf, CONF_proxy_host),
+				   &proxy_canonical_name,
+				   conf_get_int(conf, CONF_addressfamily));
+	if (sk_addr_error(proxy_addr) != NULL) {
 	    ret->error = "Proxy error: Unable to resolve proxy host name";
+            sfree(pplug);
+            sk_addr_free(proxy_addr);
 	    return (Socket)ret;
 	}
 	sfree(proxy_canonical_name);
@@ -430,14 +482,13 @@ Socket new_connection(SockAddr addr, char *hostname,
 	/* create the actual socket we will be using,
 	 * connected to our proxy server and port.
 	 */
-	ret->sub_socket = sk_new(proxy_addr, cfg->proxy_port,
+	ret->sub_socket = sk_new(proxy_addr,
+				 conf_get_int(conf, CONF_proxy_port),
 				 privport, oobinline,
-				 nodelay, (Plug) pplug);
+				 nodelay, keepalive, (Plug) pplug);
 	if (sk_socket_error(ret->sub_socket) != NULL)
 	    return (Socket) ret;
 
-	sk_addr_free(proxy_addr);
-
 	/* start the proxy negotiation process... */
 	sk_set_frozen(ret->sub_socket, 0);
 	ret->negotiate(ret, PROXY_CHANGE_NEW);
@@ -446,17 +497,17 @@ Socket new_connection(SockAddr addr, char *hostname,
     }
 
     /* no proxy, so just return the direct socket */
-    return sk_new(addr, port, privport, oobinline, nodelay, plug);
+    return sk_new(addr, port, privport, oobinline, nodelay, keepalive, plug);
 }
 
 Socket new_listener(char *srcaddr, int port, Plug plug, int local_host_only,
-		    const Config *cfg)
+		    Conf *conf, int addressfamily)
 {
     /* TODO: SOCKS (and potentially others) support inbound
      * TODO: connections via the proxy. support them.
      */
 
-    return sk_newlistener(srcaddr, port, plug, local_host_only);
+    return sk_newlistener(srcaddr, port, plug, local_host_only, addressfamily);
 }
 
 /* ----------------------------------------------------------------------
@@ -506,6 +557,7 @@ int proxy_http_negotiate (Proxy_Socket p, int change)
 	 * request
 	 */
 	char *buf, dest[512];
+	char *username, *password;
 
 	sk_getaddr(p->remote_addr, dest, lenof(dest));
 
@@ -514,18 +566,22 @@ int proxy_http_negotiate (Proxy_Socket p, int change)
 	sk_write(p->sub_socket, buf, strlen(buf));
 	sfree(buf);
 
-	if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
-	    char buf[sizeof(p->cfg.proxy_username)+sizeof(p->cfg.proxy_password)];
-	    char buf2[sizeof(buf)*4/3 + 100];
+	username = conf_get_str(p->conf, CONF_proxy_username);
+	password = conf_get_str(p->conf, CONF_proxy_password);
+	if (username[0] || password[0]) {
+	    char *buf, *buf2;
 	    int i, j, len;
-	    sprintf(buf, "%s:%s", p->cfg.proxy_username, p->cfg.proxy_password);
+	    buf = dupprintf("%s:%s", username, password);
 	    len = strlen(buf);
+	    buf2 = snewn(len * 4 / 3 + 100, char);
 	    sprintf(buf2, "Proxy-Authorization: Basic ");
 	    for (i = 0, j = strlen(buf2); i < len; i += 3, j += 4)
 		base64_encode_atom((unsigned char *)(buf+i),
 				   (len-i > 3 ? 3 : len-i), buf2+j);
 	    strcpy(buf2+j, "\r\n");
 	    sk_write(p->sub_socket, buf2, strlen(buf2));
+	    sfree(buf);
+	    sfree(buf2);
 	}
 
 	sk_write(p->sub_socket, "\r\n", 2);
@@ -580,8 +636,14 @@ int proxy_http_negotiate (Proxy_Socket p, int change)
 	    /* get the status line */
 	    len = bufchain_size(&p->pending_input_data);
 	    assert(len > 0);	       /* or we wouldn't be here */
-	    data = snewn(len, char);
+	    data = snewn(len+1, char);
 	    bufchain_fetch(&p->pending_input_data, data, len);
+	    /*
+	     * We must NUL-terminate this data, because Windows
+	     * sscanf appears to require a NUL at the end of the
+	     * string because it strlens it _first_. Sigh.
+	     */
+	    data[len] = '\0';
 
 	    eol = get_line_end(data, len);
 	    if (eol < 0) {
@@ -686,11 +748,11 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change)
 
 	int length, type, namelen;
 	char *command, addr[4], hostname[512];
+	char *username;
 
 	type = sk_addrtype(p->remote_addr);
 	if (type == ADDRTYPE_IPV6) {
-	    plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
-			 " not support IPv6", PROXY_ERROR_GENERAL, 0);
+            p->error = "Proxy error: SOCKS version 4 does not support IPv6";
 	    return 1;
 	} else if (type == ADDRTYPE_IPV4) {
 	    namelen = 0;
@@ -703,9 +765,10 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change)
 	    addr[3] = 1;
 	}
 
-	length = strlen(p->cfg.proxy_username) + namelen + 9;
+	username = conf_get_str(p->conf, CONF_proxy_username);
+	length = strlen(username) + namelen + 9;
 	command = snewn(length, char);
-	strcpy(command + 8, p->cfg.proxy_username);
+	strcpy(command + 8, username);
 
 	command[0] = 4; /* version 4 */
 	command[1] = 1; /* CONNECT command */
@@ -718,10 +781,11 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change)
 	memcpy(command + 4, addr, 4);
 
 	/* hostname */
-	memcpy(command + 8 + strlen(p->cfg.proxy_username) + 1,
+	memcpy(command + 8 + strlen(username) + 1,
 	       hostname, namelen);
 
 	sk_write(p->sub_socket, command, length);
+	sfree(username);
 	sfree(command);
 
 	p->state = 1;
@@ -842,15 +906,19 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
 	 *     0x03 = CHAP
 	 */
 
-	char command[4];
+	char command[5];
+	char *username, *password;
 	int len;
 
 	command[0] = 5; /* version 5 */
-	if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
-	    command[1] = 2;	       /* two methods supported: */
+	username = conf_get_str(p->conf, CONF_proxy_username);
+	password = conf_get_str(p->conf, CONF_proxy_password);
+	if (username[0] || password[0]) {
 	    command[2] = 0x00;	       /* no authentication */
-	    command[3] = 0x02;	       /* username/password */
-	    len = 4;
+	    len = 3;
+	    proxy_socks5_offerencryptedauth (command, &len);
+	    command[len++] = 0x02;	       /* username/password */
+	    command[1] = len - 2;	/* Number of methods supported */
 	} else {
 	    command[1] = 1;	       /* one methods supported: */
 	    command[2] = 0x00;	       /* no authentication */
@@ -906,7 +974,7 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
 	     *    authentication methods:
 	     *     0x00 = no authentication
 	     *     0x01 = GSSAPI
-	     *     0x02 = username/password 
+	     *     0x02 = username/password
 	     *     0x03 = CHAP
 	     *     0xff = no acceptable methods
 	     */
@@ -971,6 +1039,12 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
 	    p->state = 2;	       /* now proceed as authenticated */
 	}
 
+	if (p->state == 8) {
+	    int ret;
+	    ret = proxy_socks5_handlechap(p);
+	    if (ret) return ret;
+	}
+
 	if (p->state == 2) {
 
 	    /* request format:
@@ -1116,18 +1190,20 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
 	}
 
 	if (p->state == 5) {
-	    if (p->cfg.proxy_username[0] || p->cfg.proxy_password[0]) {
-		char userpwbuf[514];
+	    char *username = conf_get_str(p->conf, CONF_proxy_username);
+	    char *password = conf_get_str(p->conf, CONF_proxy_password);
+	    if (username[0] || password[0]) {
+		char userpwbuf[255 + 255 + 3];
 		int ulen, plen;
-		ulen = strlen(p->cfg.proxy_username);
+		ulen = strlen(username);
 		if (ulen > 255) ulen = 255; if (ulen < 1) ulen = 1;
-		plen = strlen(p->cfg.proxy_password);
+		plen = strlen(password);
 		if (plen > 255) plen = 255; if (plen < 1) plen = 1;
 		userpwbuf[0] = 1;      /* version number of subnegotiation */
 		userpwbuf[1] = ulen;
-		memcpy(userpwbuf+2, p->cfg.proxy_username, ulen);
+		memcpy(userpwbuf+2, username, ulen);
 		userpwbuf[ulen+2] = plen;
-		memcpy(userpwbuf+ulen+3, p->cfg.proxy_password, plen);
+		memcpy(userpwbuf+ulen+3, password, plen);
 		sk_write(p->sub_socket, userpwbuf, ulen + plen + 3);
 		p->state = 7;
 	    } else 
@@ -1139,10 +1215,9 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
 	}
 
 	if (p->state == 6) {
-	    /* TODO: Handle CHAP authentication */
-	    plug_closing(p->plug, "Proxy error: We don't support CHAP authentication",
-			 PROXY_ERROR_GENERAL, 0);
-	    return 1;
+	    int ret;
+	    ret = proxy_socks5_selectchap(p);
+	    if (ret) return ret;
 	}
 
     }
@@ -1161,103 +1236,114 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
  * standardised or at all well-defined.)
  */
 
-int proxy_telnet_negotiate (Proxy_Socket p, int change)
+char *format_telnet_command(SockAddr addr, int port, Conf *conf)
 {
-    if (p->state == PROXY_CHANGE_NEW) {
-
-	int so = 0, eo = 0;
-
-	/* we need to escape \\, \%, \r, \n, \t, \x??, \0???, 
-	 * %%, %host, %port, %user, and %pass
-	 */
-
-	while (p->cfg.proxy_telnet_command[eo] != 0) {
-
-	    /* scan forward until we hit end-of-line, 
-	     * or an escape character (\ or %) */
-	    while (p->cfg.proxy_telnet_command[eo] != 0 &&
-		   p->cfg.proxy_telnet_command[eo] != '%' &&
-		   p->cfg.proxy_telnet_command[eo] != '\\') eo++;
-
-	    /* if we hit eol, break out of our escaping loop */
-	    if (p->cfg.proxy_telnet_command[eo] == 0) break;
-
-	    /* if there was any unescaped text before the escape
-	     * character, send that now */
-	    if (eo != so) {
-		sk_write(p->sub_socket, 
-			 p->cfg.proxy_telnet_command + so, eo - so);
-	    }
-
-	    so = eo++;
+    char *fmt = conf_get_str(conf, CONF_proxy_telnet_command);
+    char *ret = NULL;
+    int retlen = 0, retsize = 0;
+    int so = 0, eo = 0;
+#define ENSURE(n) do { \
+    if (retsize < retlen + n) { \
+	retsize = retlen + n + 512; \
+	ret = sresize(ret, retsize, char); \
+    } \
+} while (0)
+
+    /* we need to escape \\, \%, \r, \n, \t, \x??, \0???, 
+     * %%, %host, %port, %user, and %pass
+     */
 
-	    /* if the escape character was the last character of
-	     * the line, we'll just stop and send it. */
-	    if (p->cfg.proxy_telnet_command[eo] == 0) break;
+    while (fmt[eo] != 0) {
 
-	    if (p->cfg.proxy_telnet_command[so] == '\\') {
+	/* scan forward until we hit end-of-line,
+	 * or an escape character (\ or %) */
+	while (fmt[eo] != 0 && fmt[eo] != '%' && fmt[eo] != '\\')
+	    eo++;
 
-		/* we recognize \\, \%, \r, \n, \t, \x??. 
-		 * anything else, we just send unescaped (including the \). 
-		 */
+	/* if we hit eol, break out of our escaping loop */
+	if (fmt[eo] == 0) break;
 
-		switch (p->cfg.proxy_telnet_command[eo]) {
+	/* if there was any unescaped text before the escape
+	 * character, send that now */
+	if (eo != so) {
+	    ENSURE(eo - so);
+	    memcpy(ret + retlen, fmt + so, eo - so);
+	    retlen += eo - so;
+	}
 
-		  case '\\':
-		    sk_write(p->sub_socket, "\\", 1);
-		    eo++;
-		    break;
+	so = eo++;
 
-		  case '%':
-		    sk_write(p->sub_socket, "%%", 1);
-		    eo++;
-		    break;
+	/* if the escape character was the last character of
+	 * the line, we'll just stop and send it. */
+	if (fmt[eo] == 0) break;
 
-		  case 'r':
-		    sk_write(p->sub_socket, "\r", 1);
-		    eo++;
-		    break;
+	if (fmt[so] == '\\') {
 
-		  case 'n':
-		    sk_write(p->sub_socket, "\n", 1);
-		    eo++;
-		    break;
-
-		  case 't':
-		    sk_write(p->sub_socket, "\t", 1);
-		    eo++;
-		    break;
+	    /* we recognize \\, \%, \r, \n, \t, \x??.
+	     * anything else, we just send unescaped (including the \).
+	     */
 
-		  case 'x':
-		  case 'X':
-		    {
+	    switch (fmt[eo]) {
+
+	      case '\\':
+		ENSURE(1);
+		ret[retlen++] = '\\';
+		eo++;
+		break;
+
+	      case '%':
+		ENSURE(1);
+		ret[retlen++] = '%';
+		eo++;
+		break;
+
+	      case 'r':
+		ENSURE(1);
+		ret[retlen++] = '\r';
+		eo++;
+		break;
+
+	      case 'n':
+		ENSURE(1);
+		ret[retlen++] = '\n';
+		eo++;
+		break;
+
+	      case 't':
+		ENSURE(1);
+		ret[retlen++] = '\t';
+		eo++;
+		break;
+
+	      case 'x':
+	      case 'X':
+		{
 		    /* escaped hexadecimal value (ie. \xff) */
 		    unsigned char v = 0;
 		    int i = 0;
 
 		    for (;;) {
 			eo++;
-			if (p->cfg.proxy_telnet_command[eo] >= '0' &&
-			    p->cfg.proxy_telnet_command[eo] <= '9')
-			    v += p->cfg.proxy_telnet_command[eo] - '0';
-			else if (p->cfg.proxy_telnet_command[eo] >= 'a' &&
-				 p->cfg.proxy_telnet_command[eo] <= 'f')
-			    v += p->cfg.proxy_telnet_command[eo] - 'a' + 10;
-			else if (p->cfg.proxy_telnet_command[eo] >= 'A' &&
-				 p->cfg.proxy_telnet_command[eo] <= 'F')
-			    v += p->cfg.proxy_telnet_command[eo] - 'A' + 10;
+			if (fmt[eo] >= '0' && fmt[eo] <= '9')
+			    v += fmt[eo] - '0';
+			else if (fmt[eo] >= 'a' && fmt[eo] <= 'f')
+			    v += fmt[eo] - 'a' + 10;
+			else if (fmt[eo] >= 'A' && fmt[eo] <= 'F')
+			    v += fmt[eo] - 'A' + 10;
 			else {
 			    /* non hex character, so we abort and just
 			     * send the whole thing unescaped (including \x)
 			     */
-			    sk_write(p->sub_socket, "\\", 1);
+			    ENSURE(1);
+			    ret[retlen++] = '\\';
 			    eo = so + 1;
 			    break;
 			}
 
 			/* we only extract two hex characters */
 			if (i == 1) {
-			    sk_write(p->sub_socket, (char *)&v, 1);
+			    ENSURE(1);
+			    ret[retlen++] = v;
 			    eo++;
 			    break;
 			}
@@ -1265,69 +1351,120 @@ int proxy_telnet_negotiate (Proxy_Socket p, int change)
 			i++;
 			v <<= 4;
 		    }
-		    }
-		    break;
-
-		  default:
-		    sk_write(p->sub_socket, 
-			     p->cfg.proxy_telnet_command + so, 2);
-		    eo++;
-		    break;
 		}
-	    } else {
+		break;
 
-		/* % escape. we recognize %%, %host, %port, %user, %pass. 
-		 * anything else, we just send unescaped (including the %). 
-		 */
-
-		if (p->cfg.proxy_telnet_command[eo] == '%') {
-		    sk_write(p->sub_socket, "%", 1);
-		    eo++;
-		}
-		else if (strnicmp(p->cfg.proxy_telnet_command + eo,
-				  "host", 4) == 0) {
-		    char dest[512];
-		    sk_getaddr(p->remote_addr, dest, lenof(dest));
-		    sk_write(p->sub_socket, dest, strlen(dest));
-		    eo += 4;
-		}
-		else if (strnicmp(p->cfg.proxy_telnet_command + eo,
-				  "port", 4) == 0) {
-		    char port[8];
-		    sprintf(port, "%i", p->remote_port);
-		    sk_write(p->sub_socket, port, strlen(port));
-		    eo += 4;
-		}
-		else if (strnicmp(p->cfg.proxy_telnet_command + eo,
-				  "user", 4) == 0) {
-		    sk_write(p->sub_socket, p->cfg.proxy_username, 
-			strlen(p->cfg.proxy_username));
-		    eo += 4;
-		}
-		else if (strnicmp(p->cfg.proxy_telnet_command + eo,
-				  "pass", 4) == 0) {
-		    sk_write(p->sub_socket, p->cfg.proxy_password, 
-			strlen(p->cfg.proxy_password));
-		    eo += 4;
-		}
-		else {
-		    /* we don't escape this, so send the % now, and
-		     * don't advance eo, so that we'll consider the
-		     * text immediately following the % as unescaped.
-		     */
-		    sk_write(p->sub_socket, "%", 1);
-		}
+	      default:
+		ENSURE(2);
+		memcpy(ret+retlen, fmt + so, 2);
+		retlen += 2;
+		eo++;
+		break;
 	    }
+	} else {
 
-	    /* resume scanning for additional escapes after this one. */
-	    so = eo;
-	}
+	    /* % escape. we recognize %%, %host, %port, %user, %pass.
+	     * %proxyhost, %proxyport. Anything else we just send
+	     * unescaped (including the %).
+	     */
 
-	/* if there is any unescaped text at the end of the line, send it */
-	if (eo != so) {
-	    sk_write(p->sub_socket, p->cfg.proxy_telnet_command + so, eo - so);
+	    if (fmt[eo] == '%') {
+		ENSURE(1);
+		ret[retlen++] = '%';
+		eo++;
+	    }
+	    else if (strnicmp(fmt + eo, "host", 4) == 0) {
+		char dest[512];
+		int destlen;
+		sk_getaddr(addr, dest, lenof(dest));
+		destlen = strlen(dest);
+		ENSURE(destlen);
+		memcpy(ret+retlen, dest, destlen);
+		retlen += destlen;
+		eo += 4;
+	    }
+	    else if (strnicmp(fmt + eo, "port", 4) == 0) {
+		char portstr[8], portlen;
+		portlen = sprintf(portstr, "%i", port);
+		ENSURE(portlen);
+		memcpy(ret + retlen, portstr, portlen);
+		retlen += portlen;
+		eo += 4;
+	    }
+	    else if (strnicmp(fmt + eo, "user", 4) == 0) {
+		char *username = conf_get_str(conf, CONF_proxy_username);
+		int userlen = strlen(username);
+		ENSURE(userlen);
+		memcpy(ret+retlen, username, userlen);
+		retlen += userlen;
+		eo += 4;
+	    }
+	    else if (strnicmp(fmt + eo, "pass", 4) == 0) {
+		char *password = conf_get_str(conf, CONF_proxy_password);
+		int passlen = strlen(password);
+		ENSURE(passlen);
+		memcpy(ret+retlen, password, passlen);
+		retlen += passlen;
+		eo += 4;
+	    }
+	    else if (strnicmp(fmt + eo, "proxyhost", 9) == 0) {
+		char *host = conf_get_str(conf, CONF_proxy_host);
+		int phlen = strlen(host);
+		ENSURE(phlen);
+		memcpy(ret+retlen, host, phlen);
+		retlen += phlen;
+		eo += 9;
+	    }
+	    else if (strnicmp(fmt + eo, "proxyport", 9) == 0) {
+		int port = conf_get_int(conf, CONF_proxy_port);
+                char pport[50];
+		int pplen;
+                sprintf(pport, "%d", port);
+                pplen = strlen(pport);
+		ENSURE(pplen);
+		memcpy(ret+retlen, pport, pplen);
+		retlen += pplen;
+		eo += 9;
+	    }
+	    else {
+		/* we don't escape this, so send the % now, and
+		 * don't advance eo, so that we'll consider the
+		 * text immediately following the % as unescaped.
+		 */
+		ENSURE(1);
+		ret[retlen++] = '%';
+	    }
 	}
 
+	/* resume scanning for additional escapes after this one. */
+	so = eo;
+    }
+
+    /* if there is any unescaped text at the end of the line, send it */
+    if (eo != so) {
+	ENSURE(eo - so);
+	memcpy(ret + retlen, fmt + so, eo - so);
+	retlen += eo - so;
+    }
+
+    ENSURE(1);
+    ret[retlen] = '\0';
+    return ret;
+
+#undef ENSURE
+}
+
+int proxy_telnet_negotiate (Proxy_Socket p, int change)
+{
+    if (p->state == PROXY_CHANGE_NEW) {
+	char *formatted_cmd;
+
+	formatted_cmd = format_telnet_command(p->remote_addr, p->remote_port,
+					      p->conf);
+
+	sk_write(p->sub_socket, formatted_cmd, strlen(formatted_cmd));
+	sfree(formatted_cmd);
+
 	p->state = 1;
 	return 0;
     }