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Commit 4656e0a3 authored by Tilman Schmidt's avatar Tilman Schmidt Committed by David S. Miller
Browse files

isdn/gigaset: restructure modem response parser (4) 



Restructure the control structure of the modem response parser
to improve readability and error handling.

Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d93187eb

drivers/isdn/gigaset/ev-layer.c

+151 −107
Original line number Diff line number Diff line
@@ -389,6 +389,20 @@ zsau_resp[] = 
	{NULL,				ZSAU_UNKNOWN}

};



/* check for and remove fixed string prefix

 * If s starts with prefix terminated by a non-alphanumeric character,

 * return pointer to the first character after that, otherwise return NULL.

 */

static char *skip_prefix(char *s, const char *prefix)

{

	while (*prefix)

		if (*s++ != *prefix++)

			return NULL;

	if (isalnum(*s))

		return NULL;

	return s;

}



/* queue event with CID */

static void add_cid_event(struct cardstate *cs, int cid, int type,

			  void *ptr, int parameter)
@@ -430,15 +444,11 @@ static void add_cid_event(struct cardstate *cs, int cid, int type, 
 */

void gigaset_handle_modem_response(struct cardstate *cs)

{

	unsigned char *argv[MAX_REC_PARAMS + 1];

	int params;

	int i, j;

	char *psep, *ptr;

	char *eoc, *psep, *ptr;

	const struct resp_type_t *rt;

	const struct zsau_resp_t *zr;

	int curarg;

	int abort;

	int cid, parameter;

	u8 type, value;



	if (!cs->cbytes) {

		/* ignore additional LFs/CRs (M10x config mode or cx100) */
@@ -456,6 +466,19 @@ void gigaset_handle_modem_response(struct cardstate *cs) 
		return;

	}



	/* look up response type */

	for (rt = resp_type; rt->response; ++rt) {

		eoc = skip_prefix(cs->respdata, rt->response);

		if (eoc)

			break;

	}

	if (!rt->response) {

		add_cid_event(cs, 0, RSP_NONE, NULL, 0);

		gig_dbg(DEBUG_EVENT, "unknown modem response: '%s'\n",

			cs->respdata);

		return;

	}



	/* check for CID */

	psep = strrchr(cs->respdata, ';');

	if (psep &&
@@ -468,120 +491,141 @@ void gigaset_handle_modem_response(struct cardstate *cs) 
		cid = 0;

	}



	/* parse line */

	argv[0] = cs->respdata;

	params = 1;

	for (i = 0; i < cs->cbytes; i++)

		switch (cs->respdata[i]) {

		case ';':

		case ',':

		case '=':

			cs->respdata[i] = 0;

			if (params > MAX_REC_PARAMS)

				dev_warn(cs->dev,

					 "too many parameters in response\n");

			else

				argv[params++] = cs->respdata + i + 1;

		}



	gig_dbg(DEBUG_EVENT, "CMD received: %s", argv[0]);

	gig_dbg(DEBUG_EVENT, "CMD received: %s", cs->respdata);

	if (cid)

		gig_dbg(DEBUG_EVENT, "CID: %d", cid);

	gig_dbg(DEBUG_EVENT, "available params: %d", params - 1);

	for (j = 1; j < params; j++)

		gig_dbg(DEBUG_EVENT, "param %d: %s", j, argv[j]);



	abort = 1;

	curarg = 0;

	while (curarg < params) {

		for (rt = resp_type; rt->response; ++rt)

			if (!strcmp(argv[curarg], rt->response))

				break;



		if (!rt->response) {

			add_cid_event(cs, 0, RSP_NONE, NULL, 0);

			gig_dbg(DEBUG_EVENT, "unknown modem response: '%s'\n",

				argv[curarg]);

			break;

		}



		++curarg;



	switch (rt->type) {

	case RT_NOTHING:

		/* check parameter separator */

		if (*eoc)

			goto bad_param;	/* extra parameter */



		add_cid_event(cs, cid, rt->resp_code, NULL, 0);

		break;



	case RT_RING:

			if (!cid) {

				dev_err(cs->dev,

					"received RING without CID!\n");

				add_cid_event(cs, 0, RSP_INVAL, NULL, 0);

				abort = 1;

			} else {

		/* check parameter separator */

		if (!*eoc)

			eoc = NULL;	/* no parameter */

		else if (*eoc++ != ',')

			goto bad_param;



		add_cid_event(cs, 0, rt->resp_code, NULL, cid);

				abort = 0;



		/* process parameters as individual responses */

		while (eoc) {

			/* look up parameter type */

			psep = NULL;

			for (rt = resp_type; rt->response; ++rt) {

				psep = skip_prefix(eoc, rt->response);

				if (psep)

					break;

			}



			/* all legal parameters are of type RT_STRING */

			if (!psep || rt->type != RT_STRING) {

				dev_warn(cs->dev,

					 "illegal RING parameter: '%s'\n",

					 eoc);

				return;

			}



			/* skip parameter value separator */

			if (*psep++ != '=')

				goto bad_param;



			/* look up end of parameter */

			eoc = strchr(psep, ',');

			if (eoc)

				*eoc++ = 0;



			/* retrieve parameter value */

			ptr = kstrdup(psep, GFP_ATOMIC);



			/* queue event */

			add_cid_event(cs, cid, rt->resp_code, ptr, 0);

		}

		break;



	case RT_ZSAU:

			if (curarg >= params) {

				add_cid_event(cs, cid, rt->resp_code, NULL,

					      ZSAU_NONE);

		/* check parameter separator */

		if (!*eoc) {

			/* no parameter */

			add_cid_event(cs, cid, rt->resp_code, NULL, ZSAU_NONE);

			break;

		}

		if (*eoc++ != '=')

			goto bad_param;



		/* look up parameter value */

		for (zr = zsau_resp; zr->str; ++zr)

				if (!strcmp(argv[curarg], zr->str))

			if (!strcmp(eoc, zr->str))

				break;

		if (!zr->str)

				dev_warn(cs->dev,

					 "%s: unknown parameter %s after ZSAU\n",

					 __func__, argv[curarg]);

			goto bad_param;



		add_cid_event(cs, cid, rt->resp_code, NULL, zr->code);

			++curarg;

		break;



	case RT_STRING:

			if (curarg < params) {

				ptr = kstrdup(argv[curarg], GFP_ATOMIC);

				if (!ptr)

					dev_err(cs->dev, "out of memory\n");

				++curarg;

			} else {

				ptr = NULL;

			}

			gig_dbg(DEBUG_EVENT, "string==%s", ptr ? ptr : "NULL");

		/* check parameter separator */

		if (*eoc++ != '=')

			goto bad_param;



		/* retrieve parameter value */

		ptr = kstrdup(eoc, GFP_ATOMIC);



		/* queue event */

		add_cid_event(cs, cid, rt->resp_code, ptr, 0);

		break;

		case RT_ZCAU:

			parameter = -1;

			if (curarg + 1 < params) {

				u8 type, value;



				i = kstrtou8(argv[curarg++], 16, &type);

				j = kstrtou8(argv[curarg++], 16, &value);

				if (i == 0 && j == 0)

	case RT_ZCAU:

		/* check parameter separators */

		if (*eoc++ != '=')

			goto bad_param;

		psep = strchr(eoc, ',');

		if (!psep)

			goto bad_param;

		*psep++ = 0;



		/* decode parameter values */

		if (kstrtou8(eoc, 16, &type) || kstrtou8(psep, 16, &value)) {

			*--psep = ',';

			goto bad_param;

		}

		parameter = (type << 8) | value;

			} else

				curarg = params - 1;



		add_cid_event(cs, cid, rt->resp_code, NULL, parameter);

		break;



	case RT_NUMBER:

			if (curarg >= params ||

			    kstrtoint(argv[curarg++], 10, &parameter))

				parameter = -1;

			gig_dbg(DEBUG_EVENT, "parameter==%d", parameter);

			add_cid_event(cs, cid, rt->resp_code, NULL, parameter);

		/* check parameter separator */

		if (*eoc++ != '=')

			goto bad_param;



		/* decode parameter value */

		if (kstrtoint(eoc, 10, &parameter))

			goto bad_param;



		/* special case ZDLE: set flag before queueing event */

		if (rt->resp_code == RSP_ZDLE)

			cs->dle = parameter;



		add_cid_event(cs, cid, rt->resp_code, NULL, parameter);

		break;

		}



		if (abort)

bad_param:

		/* parameter unexpected, incomplete or malformed */

		dev_warn(cs->dev, "bad parameter in response '%s'\n",

			 cs->respdata);

		add_cid_event(cs, cid, rt->resp_code, NULL, -1);

		break;

	}



	if (curarg != params)

		gig_dbg(DEBUG_EVENT,

			"invalid number of processed parameters: %d/%d",

			curarg, params);

	default:

		dev_err(cs->dev, "%s: internal error on '%s'\n",

			__func__, cs->respdata);

	}

}

EXPORT_SYMBOL_GPL(gigaset_handle_modem_response);