xref: /freebsd/contrib/libpcap/rpcap-protocol.c (revision 911f0260390e18cf85f3dbf2c719b593efdc1e3c)
1 /*
2  * Copyright (c) 2002 - 2005 NetGroup, Politecnico di Torino (Italy)
3  * Copyright (c) 2005 - 2008 CACE Technologies, Davis (California)
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the Politecnico di Torino, CACE Technologies
16  * nor the names of its contributors may be used to endorse or promote
17  * products derived from this software without specific prior written
18  * permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  *
32  */
33 
34 #ifdef HAVE_CONFIG_H
35 #include <config.h>
36 #endif
37 
38 #include <string.h>		/* for strlen(), ... */
39 #include <stdlib.h>		/* for malloc(), free(), ... */
40 #include <stdarg.h>		/* for functions with variable number of arguments */
41 #include <errno.h>		/* for the errno variable */
42 #include "sockutils.h"
43 #include "portability.h"
44 #include "rpcap-protocol.h"
45 #include <pcap/pcap.h>
46 
47 /*
48  * This file contains functions used both by the rpcap client and the
49  * rpcap daemon.
50  */
51 
52 /*
53  * This function sends a RPCAP error to our peer.
54  *
55  * It has to be called when the main program detects an error.
56  * It will send to our peer the 'buffer' specified by the user.
57  * This function *does not* request a RPCAP CLOSE connection. A CLOSE
58  * command must be sent explicitly by the program, since we do not know
59  * whether the error can be recovered in some way or if it is a
60  * non-recoverable one.
61  *
62  * \param sock: the socket we are currently using.
63  *
64  * \param ssl: if compiled with openssl, the optional ssl handler to use with the above socket.
65  *
66  * \param ver: the protocol version we want to put in the reply.
67  *
68  * \param errcode: a integer which tells the other party the type of error
69  * we had.
70  *
71  * \param error: an user-allocated (and '0' terminated) buffer that contains
72  * the error description that has to be transmitted to our peer. The
73  * error message cannot be longer than PCAP_ERRBUF_SIZE.
74  *
75  * \param errbuf: a pointer to a user-allocated buffer (of size
76  * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
77  * is one). It could be network problem.
78  *
79  * \return '0' if everything is fine, '-1' if some errors occurred. The
80  * error message is returned in the 'errbuf' variable.
81  */
82 int
83 rpcap_senderror(SOCKET sock, SSL *ssl, uint8 ver, unsigned short errcode, const char *error, char *errbuf)
84 {
85 	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data to be sent is buffered */
86 	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
87 	uint16 length;
88 
89 	length = (uint16)strlen(error);
90 
91 	if (length > PCAP_ERRBUF_SIZE)
92 		length = PCAP_ERRBUF_SIZE;
93 
94 	rpcap_createhdr((struct rpcap_header *) sendbuf, ver, RPCAP_MSG_ERROR, errcode, length);
95 
96 	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
97 		RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
98 		return -1;
99 
100 	if (sock_bufferize(error, length, sendbuf, &sendbufidx,
101 		RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
102 		return -1;
103 
104 	if (sock_send(sock, ssl, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) < 0)
105 		return -1;
106 
107 	return 0;
108 }
109 
110 /*
111  * This function fills in a structure of type rpcap_header.
112  *
113  * It is provided just because the creation of an rpcap header is a common
114  * task. It accepts all the values that appears into an rpcap_header, and
115  * it puts them in place using the proper hton() calls.
116  *
117  * \param header: a pointer to a user-allocated buffer which will contain
118  * the serialized header, ready to be sent on the network.
119  *
120  * \param ver: a value (in the host byte order) which will be placed into the
121  * header.ver field and that represents the protocol version number of the
122  * current message.
123  *
124  * \param type: a value (in the host byte order) which will be placed into the
125  * header.type field and that represents the type of the current message.
126  *
127  * \param value: a value (in the host byte order) which will be placed into
128  * the header.value field and that has a message-dependent meaning.
129  *
130  * \param length: a value (in the host by order) which will be placed into
131  * the header.length field, representing the payload length of the message.
132  *
133  * \return Nothing. The serialized header is returned into the 'header'
134  * variable.
135  */
136 void
137 rpcap_createhdr(struct rpcap_header *header, uint8 ver, uint8 type, uint16 value, uint32 length)
138 {
139 	memset(header, 0, sizeof(struct rpcap_header));
140 
141 	header->ver = ver;
142 	header->type = type;
143 	header->value = htons(value);
144 	header->plen = htonl(length);
145 }
146 
147 /*
148  * Convert a message type to a string containing the type name.
149  */
150 static const char *requests[] =
151 {
152 	NULL,				/* not a valid message type */
153 	"RPCAP_MSG_ERROR",
154 	"RPCAP_MSG_FINDALLIF_REQ",
155 	"RPCAP_MSG_OPEN_REQ",
156 	"RPCAP_MSG_STARTCAP_REQ",
157 	"RPCAP_MSG_UPDATEFILTER_REQ",
158 	"RPCAP_MSG_CLOSE",
159 	"RPCAP_MSG_PACKET",
160 	"RPCAP_MSG_AUTH_REQ",
161 	"RPCAP_MSG_STATS_REQ",
162 	"RPCAP_MSG_ENDCAP_REQ",
163 	"RPCAP_MSG_SETSAMPLING_REQ",
164 };
165 #define NUM_REQ_TYPES	(sizeof requests / sizeof requests[0])
166 
167 static const char *replies[] =
168 {
169 	NULL,
170 	NULL,			/* this would be a reply to RPCAP_MSG_ERROR */
171 	"RPCAP_MSG_FINDALLIF_REPLY",
172 	"RPCAP_MSG_OPEN_REPLY",
173 	"RPCAP_MSG_STARTCAP_REPLY",
174 	"RPCAP_MSG_UPDATEFILTER_REPLY",
175 	NULL,			/* this would be a reply to RPCAP_MSG_CLOSE */
176 	NULL,			/* this would be a reply to RPCAP_MSG_PACKET */
177 	"RPCAP_MSG_AUTH_REPLY",
178 	"RPCAP_MSG_STATS_REPLY",
179 	"RPCAP_MSG_ENDCAP_REPLY",
180 	"RPCAP_MSG_SETSAMPLING_REPLY",
181 };
182 #define NUM_REPLY_TYPES	(sizeof replies / sizeof replies[0])
183 
184 const char *
185 rpcap_msg_type_string(uint8 type)
186 {
187 	if (type & RPCAP_MSG_IS_REPLY) {
188 		type &= ~RPCAP_MSG_IS_REPLY;
189 		if (type >= NUM_REPLY_TYPES)
190 			return NULL;
191 		return replies[type];
192 	} else {
193 		if (type >= NUM_REQ_TYPES)
194 			return NULL;
195 		return requests[type];
196 	}
197 }
198