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Commit 63e055d1 authored by Tilman Schmidt's avatar Tilman Schmidt Committed by David S. Miller
Browse files

bas_gigaset: collapse CR/LF at end of AT response 



Copy the mechanism from ser_/usb_gigaset to avoid producing
spurious empty responses for CR/LF sequences from the device.
Add a comment in all drivers documenting that behaviour.
Correct an off by one error that might result in a one byte
buffer overflow when receiving an unexpectedly long reply.

Impact: minor bugfix
Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2ac2ed5f

drivers/isdn/gigaset/asyncdata.c

+2 −0
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ static inline int muststuff(unsigned char c) 
 * Append received bytes to the command response buffer and forward them

 * line by line to the response handler. Exit whenever a mode/state change

 * might have occurred.

 * Note: Received lines may be terminated by CR, LF, or CR LF, which will be

 * removed before passing the line to the response handler.

 * Return value:

 *	number of processed bytes

 */

drivers/isdn/gigaset/gigaset.h

+2 −2
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ 
#define GIG_COMPAT  {0, 4, 0, 0}



#define MAX_REC_PARAMS 10	/* Max. number of params in response string */

#define MAX_RESP_SIZE 512	/* Max. size of a response string */

#define MAX_RESP_SIZE 511	/* Max. size of a response string */



#define MAX_EVENTS 64		/* size of event queue */
@@ -498,7 +498,7 @@ struct cardstate { 
	spinlock_t ev_lock;



	/* current modem response */

	unsigned char respdata[MAX_RESP_SIZE];

	unsigned char respdata[MAX_RESP_SIZE+1];

	unsigned cbytes;



	/* private data of hardware drivers */

drivers/isdn/gigaset/isocdata.c

+31 −13
Original line number Diff line number Diff line
@@ -905,28 +905,48 @@ void gigaset_isoc_receive(unsigned char *src, unsigned count, 


/* == data input =========================================================== */



/* process a block of received bytes in command mode (mstate != MS_LOCKED)

 * Append received bytes to the command response buffer and forward them

 * line by line to the response handler.

 * Note: Received lines may be terminated by CR, LF, or CR LF, which will be

 * removed before passing the line to the response handler.

 */

static void cmd_loop(unsigned char *src, int numbytes, struct inbuf_t *inbuf)

{

	struct cardstate *cs = inbuf->cs;

	unsigned cbytes      = cs->cbytes;

	unsigned char c;



	while (numbytes--) {

		/* copy next character, check for end of line */

		switch (cs->respdata[cbytes] = *src++) {

		case '\r':

		c = *src++;

		switch (c) {

		case '\n':

			/* end of line */

			gig_dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",

				__func__, cbytes);

			if (cbytes >= MAX_RESP_SIZE - 1)

				dev_warn(cs->dev, "response too large\n");

			if (cbytes == 0 && cs->respdata[0] == '\r') {

				/* collapse LF with preceding CR */

				cs->respdata[0] = 0;

				break;

			}

			/* --v-- fall through --v-- */

		case '\r':

			/* end of message line, pass to response handler */

			if (cbytes >= MAX_RESP_SIZE) {

				dev_warn(cs->dev, "response too large (%d)\n",

					 cbytes);

				cbytes = MAX_RESP_SIZE;

			}

			cs->cbytes = cbytes;

			gigaset_dbg_buffer(DEBUG_TRANSCMD, "received response",

					   cbytes, cs->respdata);

			gigaset_handle_modem_response(cs);

			cbytes = 0;



			/* store EOL byte for CRLF collapsing */

			cs->respdata[0] = c;

			break;

		default:

			/* advance in line buffer, checking for overflow */

			if (cbytes < MAX_RESP_SIZE - 1)

			/* append to line buffer if possible */

			if (cbytes < MAX_RESP_SIZE)

				cs->respdata[cbytes] = c;

			cbytes++;

		}

	}
@@ -958,8 +978,6 @@ void gigaset_isoc_input(struct inbuf_t *inbuf) 
					   numbytes, src);

			gigaset_if_receive(inbuf->cs, src, numbytes);

		} else {

			gigaset_dbg_buffer(DEBUG_CMD, "received response",

					   numbytes, src);

			cmd_loop(src, numbytes, inbuf);

		}