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      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 #include <config.h>
     35 
     36 #include <string.h>		/* for strlen(), ... */
     37 #include <stdlib.h>		/* for malloc(), free(), ... */
     38 #include <stdarg.h>		/* for functions with variable number of arguments */
     39 #include <errno.h>		/* for the errno variable */
     40 #include "sockutils.h"
     41 #include "rpcap-protocol.h"
     42 #include <pcap/pcap.h>
     43 
     44 #include "portability.h"
     45 
     46 /*
     47  * This file contains functions used both by the rpcap client and the
     48  * rpcap daemon.
     49  */
     50 
     51 /*
     52  * This function sends a RPCAP error to our peer.
     53  *
     54  * It has to be called when the main program detects an error.
     55  * It will send to our peer the 'buffer' specified by the user.
     56  * This function *does not* request a RPCAP CLOSE connection. A CLOSE
     57  * command must be sent explicitly by the program, since we do not know
     58  * whether the error can be recovered in some way or if it is a
     59  * non-recoverable one.
     60  *
     61  * \param sock: the socket we are currently using.
     62  *
     63  * \param ssl: if compiled with openssl, the optional ssl handler to use with the above socket.
     64  *
     65  * \param ver: the protocol version we want to put in the reply.
     66  *
     67  * \param errcode: a integer which tells the other party the type of error
     68  * we had.
     69  *
     70  * \param error: an user-allocated (and '0' terminated) buffer that contains
     71  * the error description that has to be transmitted to our peer. The
     72  * error message cannot be longer than PCAP_ERRBUF_SIZE.
     73  *
     74  * \param errbuf: a pointer to a user-allocated buffer (of size
     75  * PCAP_ERRBUF_SIZE) that will contain the error message (in case there
     76  * is one). It could be network problem.
     77  *
     78  * \return '0' if everything is fine, '-1' if some errors occurred. The
     79  * error message is returned in the 'errbuf' variable.
     80  */
     81 int
     82 rpcap_senderror(PCAP_SOCKET sock, SSL *ssl, uint8 ver, unsigned short errcode, const char *error, char *errbuf)
     83 {
     84 	char sendbuf[RPCAP_NETBUF_SIZE];	/* temporary buffer in which data to be sent is buffered */
     85 	int sendbufidx = 0;			/* index which keeps the number of bytes currently buffered */
     86 	uint16 length;
     87 
     88 	length = (uint16)strlen(error);
     89 
     90 	if (length > PCAP_ERRBUF_SIZE)
     91 		length = PCAP_ERRBUF_SIZE;
     92 
     93 	rpcap_createhdr((struct rpcap_header *) sendbuf, ver, RPCAP_MSG_ERROR, errcode, length);
     94 
     95 	if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
     96 		RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE))
     97 		return -1;
     98 
     99 	if (sock_bufferize(error, length, sendbuf, &sendbufidx,
    100 		RPCAP_NETBUF_SIZE, SOCKBUF_BUFFERIZE, errbuf, PCAP_ERRBUF_SIZE))
    101 		return -1;
    102 
    103 	if (sock_send(sock, ssl, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) < 0)
    104 		return -1;
    105 
    106 	return 0;
    107 }
    108 
    109 /*
    110  * This function fills in a structure of type rpcap_header.
    111  *
    112  * It is provided just because the creation of an rpcap header is a common
    113  * task. It accepts all the values that appears into an rpcap_header, and
    114  * it puts them in place using the proper hton() calls.
    115  *
    116  * \param header: a pointer to a user-allocated buffer which will contain
    117  * the serialized header, ready to be sent on the network.
    118  *
    119  * \param ver: a value (in the host byte order) which will be placed into the
    120  * header.ver field and that represents the protocol version number of the
    121  * current message.
    122  *
    123  * \param type: a value (in the host byte order) which will be placed into the
    124  * header.type field and that represents the type of the current message.
    125  *
    126  * \param value: a value (in the host byte order) which will be placed into
    127  * the header.value field and that has a message-dependent meaning.
    128  *
    129  * \param length: a value (in the host by order) which will be placed into
    130  * the header.length field, representing the payload length of the message.
    131  *
    132  * \return Nothing. The serialized header is returned into the 'header'
    133  * variable.
    134  */
    135 void
    136 rpcap_createhdr(struct rpcap_header *header, uint8 ver, uint8 type, uint16 value, uint32 length)
    137 {
    138 	memset(header, 0, sizeof(struct rpcap_header));
    139 
    140 	header->ver = ver;
    141 	header->type = type;
    142 	header->value = htons(value);
    143 	header->plen = htonl(length);
    144 }
    145 
    146 /*
    147  * Convert a message type to a string containing the type name.
    148  */
    149 static const char *requests[] =
    150 {
    151 	NULL,				/* not a valid message type */
    152 	"RPCAP_MSG_ERROR",
    153 	"RPCAP_MSG_FINDALLIF_REQ",
    154 	"RPCAP_MSG_OPEN_REQ",
    155 	"RPCAP_MSG_STARTCAP_REQ",
    156 	"RPCAP_MSG_UPDATEFILTER_REQ",
    157 	"RPCAP_MSG_CLOSE",
    158 	"RPCAP_MSG_PACKET",
    159 	"RPCAP_MSG_AUTH_REQ",
    160 	"RPCAP_MSG_STATS_REQ",
    161 	"RPCAP_MSG_ENDCAP_REQ",
    162 	"RPCAP_MSG_SETSAMPLING_REQ",
    163 };
    164 #define NUM_REQ_TYPES	(sizeof requests / sizeof requests[0])
    165 
    166 static const char *replies[] =
    167 {
    168 	NULL,
    169 	NULL,			/* this would be a reply to RPCAP_MSG_ERROR */
    170 	"RPCAP_MSG_FINDALLIF_REPLY",
    171 	"RPCAP_MSG_OPEN_REPLY",
    172 	"RPCAP_MSG_STARTCAP_REPLY",
    173 	"RPCAP_MSG_UPDATEFILTER_REPLY",
    174 	NULL,			/* this would be a reply to RPCAP_MSG_CLOSE */
    175 	NULL,			/* this would be a reply to RPCAP_MSG_PACKET */
    176 	"RPCAP_MSG_AUTH_REPLY",
    177 	"RPCAP_MSG_STATS_REPLY",
    178 	"RPCAP_MSG_ENDCAP_REPLY",
    179 	"RPCAP_MSG_SETSAMPLING_REPLY",
    180 };
    181 #define NUM_REPLY_TYPES	(sizeof replies / sizeof replies[0])
    182 
    183 const char *
    184 rpcap_msg_type_string(uint8 type)
    185 {
    186 	if (type & RPCAP_MSG_IS_REPLY) {
    187 		type &= ~RPCAP_MSG_IS_REPLY;
    188 		if (type >= NUM_REPLY_TYPES)
    189 			return NULL;
    190 		return replies[type];
    191 	} else {
    192 		if (type >= NUM_REQ_TYPES)
    193 			return NULL;
    194 		return requests[type];
    195 	}
    196 }
    197