diff options
Diffstat (limited to 'rpcap-protocol.c')
| -rw-r--r-- | rpcap-protocol.c | 176 |
1 files changed, 15 insertions, 161 deletions
diff --git a/rpcap-protocol.c b/rpcap-protocol.c index 9b8f6638..a7375f47 100644 --- a/rpcap-protocol.c +++ b/rpcap-protocol.c @@ -61,13 +61,15 @@ * * \param sock: the socket we are currently using. * + * \param ver: the protocol version we want to put in the reply. + * + * \param errcode: a integer which tells the other party the type of error + * we had. + * * \param error: an user-allocated (and '0' terminated) buffer that contains * the error description that has to be transmitted to our peer. The * error message cannot be longer than PCAP_ERRBUF_SIZE. * - * \param errcode: a integer which tells the other party the type of error - * we had; currently is is not too much used. - * * \param errbuf: a pointer to a user-allocated buffer (of size * PCAP_ERRBUF_SIZE) that will contain the error message (in case there * is one). It could be network problem. @@ -76,7 +78,7 @@ * error message is returned in the 'errbuf' variable. */ int -rpcap_senderror(SOCKET sock, char *error, unsigned short errcode, char *errbuf) +rpcap_senderror(SOCKET sock, uint8 ver, unsigned short errcode, char *error, char *errbuf) { char sendbuf[RPCAP_NETBUF_SIZE]; /* temporary buffer in which data to be sent is buffered */ int sendbufidx = 0; /* index which keeps the number of bytes currently buffered */ @@ -87,7 +89,7 @@ rpcap_senderror(SOCKET sock, char *error, unsigned short errcode, char *errbuf) if (length > PCAP_ERRBUF_SIZE) length = PCAP_ERRBUF_SIZE; - rpcap_createhdr((struct rpcap_header *) sendbuf, RPCAP_MSG_ERROR, errcode, length); + rpcap_createhdr((struct rpcap_header *) sendbuf, ver, RPCAP_MSG_ERROR, errcode, length); if (sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE)) @@ -113,10 +115,14 @@ rpcap_senderror(SOCKET sock, char *error, unsigned short errcode, char *errbuf) * \param header: a pointer to a user-allocated buffer which will contain * the serialized header, ready to be sent on the network. * - * \param type: a value (in the host by order) which will be placed into the + * \param ver: a value (in the host byte order) which will be placed into the + * header.ver field and that represents the protocol version number of the + * current message. + * + * \param type: a value (in the host byte order) which will be placed into the * header.type field and that represents the type of the current message. * - * \param value: a value (in the host by order) which will be placed into + * \param value: a value (in the host byte order) which will be placed into * the header.value field and that has a message-dependent meaning. * * \param length: a value (in the host by order) which will be placed into @@ -126,11 +132,11 @@ rpcap_senderror(SOCKET sock, char *error, unsigned short errcode, char *errbuf) * variable. */ void -rpcap_createhdr(struct rpcap_header *header, uint8 type, uint16 value, uint32 length) +rpcap_createhdr(struct rpcap_header *header, uint8 ver, uint8 type, uint16 value, uint32 length) { memset(header, 0, sizeof(struct rpcap_header)); - header->ver = RPCAP_VERSION; + header->ver = ver; header->type = type; header->value = htons(value); header->plen = htonl(length); @@ -187,155 +193,3 @@ rpcap_msg_type_string(uint8 type) return requests[type]; } } - -/* - * This function checks whether the header of the received message is correct. - * - * It is a way to easily check if the message received, in a certain state - * of the RPCAP protocol Finite State Machine, is valid. This function accepts, - * as a parameter, the list of message types that are allowed in a certain - * situation, and it returns the one that occurs. - * - * \param errbuf: a pointer to a user-allocated buffer (of size - * PCAP_ERRBUF_SIZE) that will contain the error message (in case there - * is one). It could either be a problem that occurred inside this function - * (e.g. a network problem in case it tries to send an error to our peer - * and the send() call fails), an error message thathas been sent to us - * from the other party, or a version error (the message received has a - * version number that is incompatible with ours). - * - * \param sock: the socket that has to be used to receive data. This - * function can read data from socket in case the version contained into - * the message is not compatible with ours. In that case, all the message - * is purged from the socket, so that the following recv() calls will - * return a new message. - * - * \param header: a pointer to and 'rpcap_header' structure that keeps - * the data received from the network (still in network byte order) and - * that has to be checked. - * - * \param first: this function has a variable number of parameters. From - * this point on, all the messages that are valid in this context must be - * passed as parameters. The message type list must be terminated with a - * '0' value, the null message type, which means 'no more types to check'. - * The RPCAP protocol does not define anything with message type equal to - * zero, so there is no ambiguity in using this value as a list terminator. - * - * \return The message type of the message that has been detected. In case - * of errors (e.g. the header contains a type that is not listed among the - * allowed types), this function will return the following codes: - * - (-1) if the version is incompatible. - * - (-2) if the code is not among the one listed into the parameters list - * - (-3) if a network error (connection reset, ...) - * - RPCAP_MSG_ERROR if the message is an error message (it follows that - * the RPCAP_MSG_ERROR could not be present in the allowed message-types - * list, because this function checks for errors anyway) - * - * In case either the version is incompatible or nothing matches (i.e. it - * returns '-1' or '-2'), it discards the message body (i.e. it reads the - * remaining part of the message from the network and it discards it) so - * that the application is ready to receive a new message. - */ -int -rpcap_checkmsg(char *errbuf, SOCKET sock, struct rpcap_header *header, uint8 first, ...) -{ - va_list ap; - uint8 type; - int32 len; - char remote_errbuf[PCAP_ERRBUF_SIZE]; - - /* Check if the present version of the protocol can handle this message */ - if (header->ver != RPCAP_VERSION) - { - pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "Incompatible version number: message discarded."); - - /* - * Discard the rest of the packet. - */ - if (sock_discard(sock, ntohl(header->plen), NULL, 0) == -1) { - /* - * Network error. - */ - return -3; - } - return -1; - } - - va_start(ap, first); - - type = first; - - while (type != 0) - { - /* - * The message matches with one of the types listed - * There is no need of conversions since both values are uint8 - * - * Check if the other side reported an error. - * If yes, it retrieves it and it returns it back to the caller - */ - if (header->type == RPCAP_MSG_ERROR) - { - len = ntohl(header->plen); - - if (len >= PCAP_ERRBUF_SIZE) - { - if (sock_recv(sock, remote_errbuf, PCAP_ERRBUF_SIZE - 1, SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE) == -1) - { - va_end(ap); - return -3; - } - - sock_discard(sock, len - (PCAP_ERRBUF_SIZE - 1), NULL, 0); - - /* - * Copy the received string to errbuf, and - * null-terminate it. - */ - memcpy(errbuf, remote_errbuf, PCAP_ERRBUF_SIZE - 1); - errbuf[PCAP_ERRBUF_SIZE - 1] = '\0'; - } - else if (len == 0) - { - /* Empty error string. */ - errbuf[0] = '\0'; - } - else - { - if (sock_recv(sock, remote_errbuf, len, SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE) == -1) - { - va_end(ap); - return -3; - } - - /* - * Copy the received string to errbuf, and - * null-terminate it. - */ - memcpy(errbuf, remote_errbuf, len - 1); - errbuf[len] = '\0'; - } - - va_end(ap); - return header->type; - } - - if (header->type == type) - { - va_end(ap); - return header->type; - } - - /* get next argument */ - type = va_arg(ap, int); - } - - /* we already have an error, so please discard this one */ - sock_discard(sock, ntohl(header->plen), NULL, 0); - - pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "The other endpoint sent a message that is not allowed here."); - SOCK_ASSERT(errbuf, 1); - - va_end(ap); - return -2; -} |