1 /** @file
2 
3   A plugin that sets custom 204 response bodies.
4 
5   @section license License
6 
7   Licensed to the Apache Software Foundation (ASF) under one
8   or more contributor license agreements.  See the NOTICE file
9   distributed with this work for additional information
10   regarding copyright ownership.  The ASF licenses this file
11   to you under the Apache License, Version 2.0 (the
12   "License"); you may not use this file except in compliance
13   with the License.  You may obtain a copy of the License at
14 
15       http://www.apache.org/licenses/LICENSE-2.0
16 
17   Unless required by applicable law or agreed to in writing, software
18   distributed under the License is distributed on an "AS IS" BASIS,
19   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   See the License for the specific language governing permissions and
21   limitations under the License.
22  */
23 
24 #include "ts/ts.h"
25 #include "string.h"
26 
27 #define PLUGIN_NAME "custom204plugintest"
28 
29 static int
local_handler(TSCont contp,TSEvent event,void * edata)30 local_handler(TSCont contp, TSEvent event, void *edata)
31 {
32   const char *msg = "<HTML>\n"
33                     "<HEAD>\n"
34                     "<TITLE>Spec-breaking 204!</TITLE>\n"
35                     "</HEAD>\n"
36                     "\n"
37                     "<BODY>\n"
38                     "<H1>This is body content for a 204.</H1>\n"
39                     "<HR>\n"
40                     "\n"
41                     "Description: According to rfc7231 I should not have been sent to you!<BR/>\n"
42                     "This response was sent via the custom204plugin via a call to TSHttpTxnErrorBodySet.\n"
43                     "<HR>\n"
44                     "</BODY>";
45   TSHttpTxn txnp = (TSHttpTxn)edata;
46   TSMBuffer bufp = nullptr;
47   TSMLoc hdr_loc = nullptr;
48   TSMLoc url_loc = nullptr;
49   ;
50   const char *host = nullptr;
51   int host_length;
52   const char *test_host = "www.customplugin204.test";
53 
54   switch (event) {
55   case TS_EVENT_HTTP_PRE_REMAP:
56     TSDebug(PLUGIN_NAME, "event TS_EVENT_HTTP_PRE_REMAP received");
57     TSDebug(PLUGIN_NAME, "running plugin logic.");
58     if (TSHttpTxnClientReqGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
59       TSDebug(PLUGIN_NAME, "Couldn't retrieve client request header");
60       TSError("[%s] Couldn't retrieve client request header", PLUGIN_NAME);
61       goto done;
62     }
63     TSDebug(PLUGIN_NAME, "got client request");
64 
65     if (TSHttpHdrUrlGet(bufp, hdr_loc, &url_loc) != TS_SUCCESS) {
66       TSError("[%s] Couldn't retrieve request url", PLUGIN_NAME);
67       TSDebug(PLUGIN_NAME, "Couldn't retrieve request url");
68       TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
69       goto done;
70     }
71     TSDebug(PLUGIN_NAME, "got client request url");
72 
73     host = TSUrlHostGet(bufp, url_loc, &host_length);
74     if (!host) {
75       TSError("[%s] Couldn't retrieve request hostname", PLUGIN_NAME);
76       TSDebug(PLUGIN_NAME, "Couldn't retrieve request hostname");
77       TSHandleMLocRelease(bufp, hdr_loc, url_loc);
78       TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
79       goto done;
80     }
81     TSDebug(PLUGIN_NAME, "request's host was retrieved");
82 
83     if (strncmp(host, test_host, strlen(test_host)) == 0) {
84       TSDebug(PLUGIN_NAME, "host matches, hook TS_HTTP_SEND_RESPONSE_HDR_HOOK");
85       TSHttpTxnHookAdd(txnp, TS_HTTP_SEND_RESPONSE_HDR_HOOK, contp);
86       TSHandleMLocRelease(bufp, hdr_loc, url_loc);
87       TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
88       TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
89       return 0;
90     }
91     TSDebug(PLUGIN_NAME, "Host != expected host '%s'", test_host);
92     break;
93   case TS_EVENT_HTTP_SEND_RESPONSE_HDR:
94     TSDebug(PLUGIN_NAME, "Returning 204 with custom response body.");
95     TSHttpTxnStatusSet(txnp, TS_HTTP_STATUS_NO_CONTENT);
96     TSHttpTxnErrorBodySet(txnp, TSstrdup(msg), strlen(msg), TSstrdup("text/html"));
97     break;
98 
99   case TS_EVENT_HTTP_TXN_CLOSE:
100     TSDebug(PLUGIN_NAME, "event TS_EVENT_HTTP_TXN_CLOSE received");
101     TSContDestroy(contp);
102     break;
103 
104   default:
105     TSAssert(!"Unexpected event");
106     break;
107   }
108 
109 done:
110   TSHandleMLocRelease(bufp, hdr_loc, url_loc);
111   TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc);
112   TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
113   return 1;
114 }
115 
116 static int
global_handler(TSCont contp,TSEvent event,void * edata)117 global_handler(TSCont contp, TSEvent event, void *edata)
118 {
119   TSHttpTxn txnp   = (TSHttpTxn)edata;
120   TSCont txn_contp = nullptr;
121 
122   switch (event) {
123   case TS_EVENT_HTTP_TXN_START:
124     txn_contp = TSContCreate(local_handler, TSMutexCreate());
125     TSHttpTxnHookAdd(txnp, TS_HTTP_PRE_REMAP_HOOK, txn_contp);
126     TSHttpTxnHookAdd(txnp, TS_HTTP_TXN_CLOSE_HOOK, txn_contp);
127     TSDebug(PLUGIN_NAME, "hooked TS_HTTP_OS_DNS_HOOK and TS_EVENT_HTTP_TXN_CLOSE_HOOK");
128     break;
129   default:
130     TSAssert(!"Unexpected event");
131     break;
132   }
133   TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
134   return 1;
135 }
136 
137 void
TSPluginInit(int argc,const char * argv[])138 TSPluginInit(int argc, const char *argv[])
139 {
140   TSPluginRegistrationInfo info;
141 
142   info.plugin_name   = PLUGIN_NAME;
143   info.vendor_name   = "Apache Software Foundation";
144   info.support_email = "dev@trafficserver.apache.org";
145 
146   if (TSPluginRegister(&info) != TS_SUCCESS) {
147     TSError("[%s] Plugin registration failed", PLUGIN_NAME);
148   }
149 
150   TSCont contp = TSContCreate(global_handler, TSMutexCreate());
151   TSHttpHookAdd(TS_HTTP_TXN_START_HOOK, contp);
152 }
153