Compliance: reply with 400 (Bad Request) if request header is too big.

Reply with a standard 400 (Bad Request) instead of 601 (Unknown) status in
case of an ERR_TOO_BIG error. HTTP does not have a dedicated code for the
too-big header error. There is 414 (Request-URI Too Long), but Squid does not
distinguish too-large headers from too-large URIs.

Co-Advisor test case: test_case/rfc2616/longUri-65536

=== modified file 'src/HttpStatusCode.h'
--- src/HttpStatusCode.h	2010-01-01 21:16:57 +0000
+++ src/HttpStatusCode.h	2010-08-27 17:51:17 +0000
@@ -36,24 +36,26 @@ typedef enum {
     HTTP_CONFLICT = 409,
     HTTP_GONE = 410,
     HTTP_LENGTH_REQUIRED = 411,
     HTTP_PRECONDITION_FAILED = 412,
     HTTP_REQUEST_ENTITY_TOO_LARGE = 413,
     HTTP_REQUEST_URI_TOO_LARGE = 414,
     HTTP_UNSUPPORTED_MEDIA_TYPE = 415,
     HTTP_REQUESTED_RANGE_NOT_SATISFIABLE = 416,
     HTTP_EXPECTATION_FAILED = 417,
     HTTP_UNPROCESSABLE_ENTITY = 422,    /**< RFC2518 section 10.3 */
     HTTP_LOCKED = 423,                  /**< RFC2518 section 10.4 */
     HTTP_FAILED_DEPENDENCY = 424,       /**< RFC2518 section 10.5 */
     HTTP_INTERNAL_SERVER_ERROR = 500,
     HTTP_NOT_IMPLEMENTED = 501,
     HTTP_BAD_GATEWAY = 502,
     HTTP_SERVICE_UNAVAILABLE = 503,
     HTTP_GATEWAY_TIMEOUT = 504,
     HTTP_HTTP_VERSION_NOT_SUPPORTED = 505,
     HTTP_INSUFFICIENT_STORAGE = 507,    /**< RFC2518 section 10.6 */
     HTTP_INVALID_HEADER = 600,          /**< Squid header parsing error */
-    HTTP_HEADER_TOO_LARGE = 601         /* Header too large to process */
+    HTTP_HEADER_TOO_LARGE = 601         /**< Header too large to process. Used
+                                             internally only, replying to client
+                                             with HTTP_BAD_REQUEST instead. */
 } http_status;
 
 #endif /* _SQUID_SRC_HTTP_STATUSCODE_H */

=== modified file 'src/client_side.cc'
--- src/client_side.cc	2010-08-24 04:18:51 +0000
+++ src/client_side.cc	2010-08-27 17:47:19 +0000
@@ -2390,41 +2390,41 @@ clientProcessRequest(ConnStateData *conn
 {
     ClientHttpRequest *http = context->http;
     HttpRequest *request = NULL;
     bool notedUseOfBuffer = false;
     bool tePresent = false;
     bool deChunked = false;
     bool mustReplyToOptions = false;
     bool unsupportedTe = false;
 
     /* We have an initial client stream in place should it be needed */
     /* setup our private context */
     context->registerWithConn();
 
     if (context->flags.parsed_ok == 0) {
         clientStreamNode *node = context->getClientReplyContext();
         debugs(33, 1, "clientProcessRequest: Invalid Request");
         clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
         assert (repContext);
         switch (hp->request_parse_status) {
         case HTTP_HEADER_TOO_LARGE:
-            repContext->setReplyToError(ERR_TOO_BIG, HTTP_HEADER_TOO_LARGE, method, http->uri, conn->peer, NULL, conn->in.buf, NULL);
+            repContext->setReplyToError(ERR_TOO_BIG, HTTP_BAD_REQUEST, method, http->uri, conn->peer, NULL, conn->in.buf, NULL);
             break;
         case HTTP_METHOD_NOT_ALLOWED:
             repContext->setReplyToError(ERR_UNSUP_REQ, HTTP_METHOD_NOT_ALLOWED, method, http->uri, conn->peer, NULL, conn->in.buf, NULL);
             break;
         default:
             repContext->setReplyToError(ERR_INVALID_REQ, HTTP_BAD_REQUEST, method, http->uri, conn->peer, NULL, conn->in.buf, NULL);
         }
         assert(context->http->out.offset == 0);
         context->pullData();
         conn->flags.readMoreRequests = false;
         goto finish;
     }
 
     if ((request = HttpRequest::CreateFromUrlAndMethod(http->uri, method)) == NULL) {
         clientStreamNode *node = context->getClientReplyContext();
         debugs(33, 5, "Invalid URL: " << http->uri);
         clientReplyContext *repContext = dynamic_cast<clientReplyContext *>(node->data.getRaw());
         assert (repContext);
         repContext->setReplyToError(ERR_INVALID_URL, HTTP_BAD_REQUEST, method, http->uri, conn->peer, NULL, NULL, NULL);
         assert(context->http->out.offset == 0);