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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: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tilman Schmidt 2015-03-21 20:15:32 +01:00 committed by David S. Miller
parent d93187eb10
commit 4656e0a360
1 changed files with 151 additions and 107 deletions
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258
drivers/isdn/gigaset/ev-layer.c
View File

@ -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;
switch (rt->type) {
case RT_NOTHING:
/* check parameter separator */
if (*eoc)
goto bad_param; /* extra parameter */
if (!rt->response) {
add_cid_event(cs, 0, RSP_NONE, NULL, 0);
gig_dbg(DEBUG_EVENT, "unknown modem response: '%s'\n",
argv[curarg]);
break;
}
add_cid_event(cs, cid, rt->resp_code, NULL, 0);
break;
++curarg;
case RT_RING:
/* check parameter separator */
if (!*eoc)
eoc = NULL; /* no parameter */
else if (*eoc++ != ',')
goto bad_param;
switch (rt->type) {
case RT_NOTHING:
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 {
add_cid_event(cs, 0, rt->resp_code, NULL, cid);
abort = 0;
}
break;
case RT_ZSAU:
if (curarg >= params) {
add_cid_event(cs, cid, rt->resp_code, NULL,
ZSAU_NONE);
break;
}
for (zr = zsau_resp; zr->str; ++zr)
if (!strcmp(argv[curarg], zr->str))
add_cid_event(cs, 0, rt->resp_code, NULL, cid);
/* 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;
if (!zr->str)
dev_warn(cs->dev,
"%s: unknown parameter %s after ZSAU\n",
__func__, argv[curarg]);
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");
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)
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);
if (rt->resp_code == RSP_ZDLE)
cs->dle = parameter;
/* 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:
/* check parameter separator */
if (!*eoc) {
/* no parameter */
add_cid_event(cs, cid, rt->resp_code, NULL, ZSAU_NONE);
break;
}
if (*eoc++ != '=')
goto bad_param;
if (abort)
break;
/* look up parameter value */
for (zr = zsau_resp; zr->str; ++zr)
if (!strcmp(eoc, zr->str))
break;
if (!zr->str)
goto bad_param;
add_cid_event(cs, cid, rt->resp_code, NULL, zr->code);
break;
case RT_STRING:
/* 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:
/* 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;
add_cid_event(cs, cid, rt->resp_code, NULL, parameter);
break;
case RT_NUMBER:
/* 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;
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;
default:
dev_err(cs->dev, "%s: internal error on '%s'\n",
__func__, cs->respdata);
}
if (curarg != params)
gig_dbg(DEBUG_EVENT,
"invalid number of processed parameters: %d/%d",
curarg, params);
}
EXPORT_SYMBOL_GPL(gigaset_handle_modem_response);