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Date: Sat, 21 Mar 2015 20:15:32 +0100 (CET)
From: Tilman Schmidt <tilman@...p.cc>
To: netdev@...r.kernel.org
Cc: David Miller <davem@...emloft.net>, Hansjoerg Lipp <hjlipp@....de>,
Karsten Keil <isdn@...ux-pingi.de>,
isdn4linux@...tserv.isdn4linux.de
Subject: [PATCH 4/4] 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@...p.cc>
---
drivers/isdn/gigaset/ev-layer.c | 258 +++++++++++++++++++++++-----------------
1 file changed, 151 insertions(+), 107 deletions(-)
diff --git a/drivers/isdn/gigaset/ev-layer.c b/drivers/isdn/gigaset/ev-layer.c
index dc6e6a3..1cfcea6 100644
--- a/drivers/isdn/gigaset/ev-layer.c
+++ b/drivers/isdn/gigaset/ev-layer.c
@@ -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;
- }
+ switch (rt->type) {
+ case RT_NOTHING:
+ /* check parameter separator */
+ if (*eoc)
+ goto bad_param; /* extra parameter */
- ++curarg;
+ add_cid_event(cs, cid, rt->resp_code, NULL, 0);
+ break;
- 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))
+ case RT_RING:
+ /* 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);
+
+ /* 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)
+ }
+
+ /* all legal parameters are of type RT_STRING */
+ if (!psep || rt->type != RT_STRING) {
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;
+ "illegal RING parameter: '%s'\n",
+ eoc);
+ return;
}
- gig_dbg(DEBUG_EVENT, "string==%s", ptr ? ptr : "NULL");
+
+ /* 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_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, ¶meter))
- 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;
- break;
}
+ break;
- if (abort)
+ 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 (curarg != params)
- gig_dbg(DEBUG_EVENT,
- "invalid number of processed parameters: %d/%d",
- curarg, params);
+ /* 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, ¶meter))
+ 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);
+ }
}
EXPORT_SYMBOL_GPL(gigaset_handle_modem_response);
--
1.9.2.459.g68773ac
--
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