1 /** @file
2
3 A brief file description
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 /* output_header.c: a plugin prints out the client request header
25 * fields to stdout
26 * A sample internal plugin to use the HdrPrint functions and the TSIOBuffers
27 * that the functions utilize.
28 *
29 * The plugin simply prints all the incoming request headers
30 *
31 * Note: tested on Solaris only.
32 */
33
34 #include <stdio.h>
35 #include <string.h>
36 #include <unistd.h>
37
38 #include "ts/ts.h"
39 #include "tscore/ink_defs.h"
40
41 #define PLUGIN_NAME "output_header"
42
43 static void
handle_dns(TSHttpTxn txnp,TSCont contp ATS_UNUSED)44 handle_dns(TSHttpTxn txnp, TSCont contp ATS_UNUSED)
45 {
46 TSMBuffer bufp;
47 TSMLoc hdr_loc;
48
49 TSIOBuffer output_buffer;
50 TSIOBufferReader reader;
51 int total_avail;
52
53 TSIOBufferBlock block;
54 const char *block_start;
55 int64_t block_avail;
56
57 char *output_string;
58 int64_t output_len;
59
60 if (TSHttpTxnClientReqGet(txnp, &bufp, &hdr_loc) != TS_SUCCESS) {
61 TSDebug(PLUGIN_NAME, "couldn't retrieve client request header");
62 TSError("[%s] Couldn't retrieve client request header", PLUGIN_NAME);
63 goto done;
64 }
65
66 output_buffer = TSIOBufferCreate();
67 reader = TSIOBufferReaderAlloc(output_buffer);
68
69 /* This will print just MIMEFields and not
70 the http request line */
71 TSDebug(PLUGIN_NAME, "Printing the hdrs ... ");
72 TSMimeHdrPrint(bufp, hdr_loc, output_buffer);
73
74 if (TSHandleMLocRelease(bufp, TS_NULL_MLOC, hdr_loc) == TS_ERROR) {
75 TSDebug(PLUGIN_NAME, "non-fatal: error releasing MLoc");
76 TSError("[%s] non-fatal: Couldn't release MLoc", PLUGIN_NAME);
77 }
78
79 /* Find out how the big the complete header is by
80 seeing the total bytes in the buffer. We need to
81 look at the buffer rather than the first block to
82 see the size of the entire header */
83 total_avail = TSIOBufferReaderAvail(reader);
84
85 /* Allocate the string with an extra byte for the string
86 terminator */
87 output_string = (char *)TSmalloc(total_avail + 1);
88 output_len = 0;
89
90 /* We need to loop over all the buffer blocks to make
91 sure we get the complete header since the header can
92 be in multiple blocks */
93 block = TSIOBufferReaderStart(reader);
94 while (block) {
95 block_start = TSIOBufferBlockReadStart(block, reader, &block_avail);
96
97 /* We'll get a block pointer back even if there is no data
98 left to read so check for this condition and break out of
99 the loop. A block with no data to read means we've exhausted
100 buffer of data since if there was more data on a later
101 block in the chain, this block would have been skipped over */
102 if (block_avail == 0) {
103 break;
104 }
105
106 memcpy(output_string + output_len, block_start, block_avail);
107 output_len += block_avail;
108
109 /* Consume the data so that we get to the next block */
110 TSIOBufferReaderConsume(reader, block_avail);
111
112 /* Get the next block now that we've consumed the
113 data off the last block */
114 block = TSIOBufferReaderStart(reader);
115 }
116
117 /* Terminate the string */
118 output_string[output_len] = '\0';
119 output_len++;
120
121 /* Free up the TSIOBuffer that we used to print out the header */
122 TSIOBufferReaderFree(reader);
123 TSIOBufferDestroy(output_buffer);
124
125 /* Although I'd never do this a production plugin, printf
126 the header so that we can see it's all there */
127 TSDebug(PLUGIN_NAME, "%s", output_string);
128
129 TSfree(output_string);
130
131 done:
132 TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
133 }
134
135 static int
hdr_plugin(TSCont contp,TSEvent event,void * edata)136 hdr_plugin(TSCont contp, TSEvent event, void *edata)
137 {
138 TSHttpTxn txnp = (TSHttpTxn)edata;
139
140 switch (event) {
141 case TS_EVENT_HTTP_OS_DNS:
142 handle_dns(txnp, contp);
143 return 0;
144 default:
145 break;
146 }
147
148 return 0;
149 }
150
151 void
TSPluginInit(int argc ATS_UNUSED,const char * argv[]ATS_UNUSED)152 TSPluginInit(int argc ATS_UNUSED, const char *argv[] ATS_UNUSED)
153 {
154 TSPluginRegistrationInfo info;
155
156 info.plugin_name = PLUGIN_NAME;
157 info.vendor_name = "Apache Software Foundation";
158 info.support_email = "dev@trafficserver.apache.org";
159
160 if (TSPluginRegister(&info) != TS_SUCCESS) {
161 TSError("[%s] Plugin registration failed", PLUGIN_NAME);
162
163 goto error;
164 }
165
166 TSHttpHookAdd(TS_HTTP_OS_DNS_HOOK, TSContCreate(hdr_plugin, NULL));
167
168 error:
169 TSError("[%s] Plugin not initialized", PLUGIN_NAME);
170 }
171