Redo the message processing in the server.

Have two service loops, one of which runs before we are authenticated
(so the only messages we accept are "authenticate me" messages) and one
which runs after we are authenticated (where we can accept command
messages, but not "authenticate me" messages).

Have the service loops do protocol version checking; currently, we only
support one version, but the first loop would do protocol negotiation in
the future, while the second loop would treat messages with a version
other than the negotiated one as an error (and there might be different
loops for different versions, as some or all messages might have
different formats with different versions).

They already need a switch statement to switch on the message type, so
we don't need to have rpcap_checkmsg() do the type checking.

Have routines to process the various message types; they do all the work
of processing the message, and return 0 on success, send an error
message to the client and return 0 on failure, and log an error message
and return -1 on a network error.

Check for errors when receiving and sending network data; always log
those messages.

Check to make sure the message length isn't too short; send an error
message to the client, and discard the message, if it is.

1 files changed, 11 insertions, 9 deletions

diff --git a/rpcap-protocol.h b/rpcap-protocol.h
index 6c6f13ba..1e4b3763 100644
--- a/rpcap-protocol.h
+++ b/rpcap-protocol.h
@@ -265,6 +265,8 @@ struct rpcap_sampling
 };
 
 /* Messages field coding */
+#define RPCAP_MSG_IS_REPLY		0x080	/* Flag indicating a reply */
+
 #define RPCAP_MSG_ERROR			1	/* Message that keeps an error notification */
 #define RPCAP_MSG_FINDALLIF_REQ		2	/* Request to list all the remote interfaces */
 #define RPCAP_MSG_OPEN_REQ		3	/* Request to open a remote device */
@@ -277,14 +279,14 @@ struct rpcap_sampling
 #define RPCAP_MSG_ENDCAP_REQ		10	/* Stops the current capture, keeping the device open */
 #define RPCAP_MSG_SETSAMPLING_REQ	11	/* Set sampling parameters */
 
-#define RPCAP_MSG_FINDALLIF_REPLY	(128+RPCAP_MSG_FINDALLIF_REQ)		/* Keeps the list of all the remote interfaces */
-#define RPCAP_MSG_OPEN_REPLY		(128+RPCAP_MSG_OPEN_REQ)		/* The remote device has been opened correctly */
-#define RPCAP_MSG_STARTCAP_REPLY	(128+RPCAP_MSG_STARTCAP_REQ)		/* The capture is starting correctly */
-#define RPCAP_MSG_UPDATEFILTER_REPLY	(128+RPCAP_MSG_UPDATEFILTER_REQ)	/* The filter has been applied correctly on the remote device */
-#define RPCAP_MSG_AUTH_REPLY		(128+RPCAP_MSG_AUTH_REQ)		/* Sends a message that says 'ok, authorization successful' */
-#define RPCAP_MSG_STATS_REPLY		(128+RPCAP_MSG_STATS_REQ)		/* Message that keeps the network statistics */
-#define RPCAP_MSG_ENDCAP_REPLY		(128+RPCAP_MSG_ENDCAP_REQ)		/* Confirms that the capture stopped successfully */
-#define RPCAP_MSG_SETSAMPLING_REPLY	(128+RPCAP_MSG_SETSAMPLING_REQ)		/* Confirms that the capture stopped successfully */
+#define RPCAP_MSG_FINDALLIF_REPLY	(RPCAP_MSG_FINDALLIF_REQ | RPCAP_MSG_IS_REPLY)		/* Keeps the list of all the remote interfaces */
+#define RPCAP_MSG_OPEN_REPLY		(RPCAP_MSG_OPEN_REQ | RPCAP_MSG_IS_REPLY)		/* The remote device has been opened correctly */
+#define RPCAP_MSG_STARTCAP_REPLY	(RPCAP_MSG_STARTCAP_REQ | RPCAP_MSG_IS_REPLY)		/* The capture is starting correctly */
+#define RPCAP_MSG_UPDATEFILTER_REPLY	(RPCAP_MSG_UPDATEFILTER_REQ | RPCAP_MSG_IS_REPLY)	/* The filter has been applied correctly on the remote device */
+#define RPCAP_MSG_AUTH_REPLY		(RPCAP_MSG_AUTH_REQ | RPCAP_MSG_IS_REPLY)		/* Sends a message that says 'ok, authorization successful' */
+#define RPCAP_MSG_STATS_REPLY		(RPCAP_MSG_STATS_REQ | RPCAP_MSG_IS_REPLY)		/* Message that keeps the network statistics */
+#define RPCAP_MSG_ENDCAP_REPLY		(RPCAP_MSG_ENDCAP_REQ | RPCAP_MSG_IS_REPLY)		/* Confirms that the capture stopped successfully */
+#define RPCAP_MSG_SETSAMPLING_REPLY	(RPCAP_MSG_SETSAMPLING_REQ | RPCAP_MSG_IS_REPLY)		/* Confirms that the capture stopped successfully */
 
 #define RPCAP_STARTCAPREQ_FLAG_PROMISC		0x00000001	/* Enables promiscuous mode (default: disabled) */
 #define RPCAP_STARTCAPREQ_FLAG_DGRAM		0x00000002	/* Use a datagram (i.e. UDP) connection for the data stream (default: use TCP)*/
@@ -327,8 +329,8 @@ struct rpcap_sampling
 
 #include "sockutils.h"
 
-extern int rpcap_checkver(SOCKET sock, struct rpcap_header *header, char *errbuf);
 extern void rpcap_createhdr(struct rpcap_header *header, uint8 type, uint16 value, uint32 length);
+extern const char *rpcap_msg_type_string(uint8 type);
 extern int rpcap_checkmsg(char *errbuf, SOCKET sock, struct rpcap_header *header, uint8 first, ...);
 extern int rpcap_senderror(SOCKET sock, char *error, unsigned short errcode, char *errbuf);