Github user SolidWallOfCode commented on a diff in the pull request:
https://github.com/apache/trafficserver/pull/843#discussion_r75854284
--- Diff: plugins/experimental/carp/carp.cc ---
@@ -0,0 +1,713 @@
+/** @file
+
+ A brief file description
+
+ @section license License
+
+ Licensed to the Apache Software Foundation (ASF) under one
+ or more contributor license agreements. See the NOTICE file
+ distributed with this work for additional information
+ regarding copyright ownership. The ASF licenses this file
+ to you under the Apache License, Version 2.0 (the
+ "License"); you may not use this file except in compliance
+ with the License. You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+ */
+
+#include <errno.h>
+
+#include <string>
+#include <sstream>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <memory.h>
+
+#include <ts/ts.h>
+
+#include "Common.h"
+#include "CarpConfig.h"
+#include "CarpConfigPool.h"
+#include "CarpHashAlgorithm.h"
+#include "UrlComponents.h"
+
+using namespace std;
+
+CarpConfigPool* g_CarpConfigPool = NULL;
+int g_carpSelectedHostArgIndex = 0;
+TSTextLogObject g_logObject = NULL;
+
+const char *logFileName = "carp";
+
+//////////////////////////////////////////////////////////////////////////////
+//////////////////////////////////////////////////////////////////////////////
+/*
+ check for our carp routed header, dump status if requested
+ */
+static int
+processCarpRoutedHeader(TSHttpTxn txnp, TSMBuffer bufp, TSMLoc hdr_loc)
+{
+ string value;
+ if (getHeader(bufp, hdr_loc, CARP_ROUTED_HEADER, value)) { // if found
header
+ if (value.compare("1") == 0) { // is loop prevention value
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with loop prevention value,
not forwarding again", CARP_ROUTED_HEADER.c_str());
+ return 0;
+ } else if (value.compare("dump") == 0) { // is dump status request
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with dump request",
CARP_ROUTED_HEADER.c_str());
+ string status;
+ g_CarpConfigPool->getGlobalHashAlgo()->dump(status);
+ TSHttpTxnSetHttpRetStatus(txnp, TS_HTTP_STATUS_MULTI_STATUS);
+ TSHttpTxnErrorBodySet(txnp, TSstrdup(status.c_str()),
status.length(), NULL);
+ return -1;
+ }
+ TSDebug(DEBUG_TAG_HOOK, "Found %s header with unknown value of %s,
ignoring", CARP_ROUTED_HEADER.c_str(), value.c_str());
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ }
+ return 1; // all OK
+}
+
+static bool
+checkListForSelf(std::vector<HashNode *> list)
+{
+ for (size_t k = 0; k < list.size(); k++) {
+ if (list[k]->isSelf) return true;
+ }
+ return false;
+}
+
+/**
+ bIsPOSTRemap = false --- Hash request and forward to peer
+ bIsPOSTRemap = true --- hash request, extract OS sockaddr, insert
forwarding header, forward
+ */
+static int
+handleRequestProcessing(TSCont contp, TSEvent event, void *edata, bool
bIsPOSTRemap)
+{
+ TSHttpTxn txnp = (TSHttpTxn) edata;
+ TSMBuffer bufp;
+ TSMLoc hdr_loc;
+ TSMLoc url_loc;
+
+ // get the client request so we can get URL and add header
+ if (TSHttpTxnClientReqGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
+ TSError("carp couldn't get request headers");
+ return -1;
+ }
+
+ int method_len;
+ const char *method = TSHttpHdrMethodGet(bufp, hdr_loc, &method_len);
+ if (NULL == method) {
+ TSError("carp couldn't get http method");
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return -1;
+ }
+ if (((method_len == TS_HTTP_LEN_DELETE) && (strncasecmp(method,
TS_HTTP_METHOD_DELETE, TS_HTTP_LEN_DELETE) == 0)) ||
+ ((method_len == TS_HTTP_LEN_PURGE) && (strncasecmp(method,
TS_HTTP_METHOD_PURGE, TS_HTTP_LEN_PURGE) == 0))) {
+ TSDebug(DEBUG_TAG_HOOK, "Request method is '%s' so not routing
request", string(method,method_len).c_str());
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return 0;
+ }
+
+ if (TSHttpHdrUrlGet(bufp, hdr_loc, &url_loc) != TS_SUCCESS) {
+ TSError("carp couldn't get url");
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return -1;
+ }
+ // if has carp loop prevention header, do not remap
+ int iTemp = processCarpRoutedHeader(txnp, bufp, hdr_loc);
+ if(iTemp <= 0) { // if dump or do not remap
+ // check origin client request's scheme for premap mode
+ if (!bIsPOSTRemap) {
+ string oriScheme;
+ if (!getHeader(bufp, hdr_loc, CARP_PREMAP_SCHEME, oriScheme)) {
+ TSDebug(DEBUG_TAG_HOOK, "couldn't get '%s' header",
CARP_PREMAP_SCHEME.c_str());
+ } else {
+ bool isHttps = (oriScheme == TS_URL_SCHEME_HTTPS);
+
+ if (isHttps) {
+ TSUrlSchemeSet(bufp, url_loc, TS_URL_SCHEME_HTTPS,
TS_URL_LEN_HTTPS);
+ } else {
+ TSUrlSchemeSet(bufp, url_loc, TS_URL_SCHEME_HTTP,
TS_URL_LEN_HTTP);
+ }
+
+ removeHeader(bufp, hdr_loc, CARP_STATUS_HEADER);
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ removeHeader(bufp, hdr_loc, CARP_PREMAP_SCHEME.c_str());
+ TSDebug(DEBUG_TAG_HOOK, "Set client request's scheme to %s through
%s header",
+ isHttps?"https":"http", CARP_PREMAP_SCHEME.c_str());
+ }
+ } else {
+ removeHeader(bufp, hdr_loc, CARP_ROUTED_HEADER);
+ }
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return iTemp;
+ }
+
+ UrlComponents reqUrl;
+ reqUrl.populate(bufp, url_loc);
+ // the url ONLY used to determine the cache owner
+ string sUrl;
+
+ if (!bIsPOSTRemap) { // if pre-remap, then host not in URL so get from
header
+ string sHost;
+ if (!getHeader(bufp, hdr_loc, TS_MIME_FIELD_HOST, sHost)) {
+ TSDebug(DEBUG_TAG_HOOK, "Could not find host header, ignoring it");
+ }
+ reqUrl.setHost(sHost);
+
+ //[YTSATS-836] heuristically ignore the scheme and port when calculate
cache owner
+ UrlComponents normalizedUrl = reqUrl;
+ normalizedUrl.setScheme(CARP_SCHEME_FOR_HASH);
+ normalizedUrl.setPort(CARP_PORT_FOR_HASH);
+ normalizedUrl.construct(sUrl);
+ } else {
+ reqUrl.construct(sUrl);
+ }
+
+
+ if (g_CarpConfigPool->getGlobalConfig()->hasWhiteList()) {
+ string sCarpable;
+ if (!getHeader(bufp, hdr_loc, CARPABLE_HEADER, sCarpable)) { // if no
carpable header check whitelist
+ if
(!g_CarpConfigPool->getGlobalConfig()->isWhiteListed(reqUrl.getHost())) { // if
white list exists, then host must be present
+ TSDebug(DEBUG_TAG_HOOK, "Host '%s' is not whitelisted, not going
through carp", reqUrl.getHost().c_str());
+ TSHandleMLocRelease(bufp, hdr_loc, url_loc);
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return 0;
+ } else {
+ TSDebug(DEBUG_TAG_HOOK, "Found host (%s) whitelisted,
routing...",reqUrl.getHost().c_str());
+ }
+ } else { // found carpable header, make sure it's 1
+ if (sCarpable.compare("1") != 0) { // carpable header present but
not 0, be strict and do not forward request
+ TSDebug(DEBUG_TAG_HOOK, "Carpable (%s) present but value not
acceptable (%s)", CARPABLE_HEADER.c_str(), sCarpable.c_str());
+ TSHandleMLocRelease(bufp, hdr_loc, url_loc);
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return 0;
+ } else {
+ TSDebug(DEBUG_TAG_HOOK, "Found Carpable header, routing...");
+ }
+ }
+ } else { // no whitelist so blacklist could be used
+ if
(g_CarpConfigPool->getGlobalConfig()->isBlackListed(reqUrl.getHost())) { // if
host black listed, do not carp
+ TSDebug(DEBUG_TAG_HOOK, "Host '%s' is blacklisted, not going through
carp", reqUrl.getHost().c_str());
+ TSHandleMLocRelease(bufp, hdr_loc, url_loc);
+ TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
+ return 0;
+ }
+ }
+
+ TSDebug(DEBUG_TAG_HOOK, "URL to hash with=%s", sUrl.c_str());
+
+ // get nodeList and select node to forward to
+ std::vector<HashNode *> nodeList =
g_CarpConfigPool->getGlobalHashAlgo()->getRemapProxyList(sUrl);
--- End diff --
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