Richard Atterer brought a patch that added support for SOCKS4a proxies, which

is an inofficial PROXY4 variant that sends the hostname to the proxy instead
of the resolved address (which is already supported by SOCKS5).  --socks4a is
the curl command line option for it and CURLOPT_PROXYTYPE can now be set to
CURLPROXY_SOCKS4A as well.

1 files changed, 40 insertions, 9 deletions

diff --git a/lib/socks.c b/lib/socks.c
index 2b3113ddf..5146b0dc4 100644
--- a/lib/socks.c
+++ b/lib/socks.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -118,16 +118,19 @@ static int blockread_all(struct connectdata *conn, /* connection data */
 *   http://socks.permeo.com/protocol/socks4.protocol
 *
 * Note :
-*   Nonsupport "SOCKS 4A (Simple Extension to SOCKS 4 Protocol)"
+*   Set protocol4a=true for  "SOCKS 4A (Simple Extension to SOCKS 4 Protocol)"
 *   Nonsupport "Identification Protocol (RFC1413)"
 */
 CURLcode Curl_SOCKS4(const char *proxy_name,
                      const char *hostname,
                      int remote_port,
                      int sockindex,
-                     struct connectdata *conn)
+                     struct connectdata *conn,
+                     bool protocol4a)
 {
-  unsigned char socksreq[262]; /* room for SOCKS4 request incl. user id */
+#define SOCKS4REQLEN 262
+  unsigned char socksreq[SOCKS4REQLEN]; /* room for SOCKS4 request incl. user
+                                           id */
   int result;
   CURLcode code;
   curl_socket_t sock = conn->sock[sockindex];
@@ -165,8 +168,8 @@ CURLcode Curl_SOCKS4(const char *proxy_name,
   socksreq[1] = 1; /* connect */
   *((unsigned short*)&socksreq[2]) = htons((unsigned short)remote_port);
 
-  /* DNS resolve */
-  {
+  /* DNS resolve only for SOCKS4, not SOCKS4a */
+  if (!protocol4a) {
     struct Curl_dns_entry *dns;
     Curl_addrinfo *hp=NULL;
     int rc;
@@ -225,15 +228,40 @@ CURLcode Curl_SOCKS4(const char *proxy_name,
   {
     ssize_t actualread;
     ssize_t written;
+    ssize_t hostnamelen = 0;
     int packetsize = 9 +
       (int)strlen((char*)socksreq + 8); /* size including NUL */
 
+    /* If SOCKS4a, set special invalid IP address 0.0.0.x */
+    if (protocol4a) {
+      socksreq[4] = 0;
+      socksreq[5] = 0;
+      socksreq[6] = 0;
+      socksreq[7] = 1;
+      /* If still enough room in buffer, also append hostname */
+      hostnamelen = strlen(hostname) + 1; /* length including NUL */
+      if (packetsize + hostnamelen <= SOCKS4REQLEN)
+        strcpy((char*)socksreq + packetsize, hostname);
+      else
+        hostnamelen = 0; /* Flag: hostname did not fit in buffer */
+    }
+
     /* Send request */
-    code = Curl_write(conn, sock, (char *)socksreq, packetsize, &written);
-    if((code != CURLE_OK) || (written != packetsize)) {
+    code = Curl_write(conn, sock, (char *)socksreq, packetsize + hostnamelen,
+                      &written);
+    if((code != CURLE_OK) || (written != packetsize + hostnamelen)) {
       failf(data, "Failed to send SOCKS4 connect request.");
       return CURLE_COULDNT_CONNECT;
     }
+    if (protocol4a && hostnamelen == 0) {
+      /* SOCKS4a with very long hostname - send that name separately */
+      hostnamelen = strlen(hostname) + 1;
+      code = Curl_write(conn, sock, (char *)hostname, hostnamelen, &written);
+      if((code != CURLE_OK) || (written != hostnamelen)) {
+        failf(data, "Failed to send SOCKS4 connect request.");
+        return CURLE_COULDNT_CONNECT;
+      }
+    }
 
     packetsize = 8; /* receive data size */
 
@@ -275,7 +303,10 @@ CURLcode Curl_SOCKS4(const char *proxy_name,
     switch(socksreq[1])
     {
     case 90:
-      infof(data, "SOCKS4 request granted.\n");
+      if (protocol4a)
+        infof(data, "SOCKS4a request granted.\n");
+      else
+        infof(data, "SOCKS4 request granted.\n");
       break;
     case 91:
       failf(data,