LAPD: Propagate lapd_receive() errors to the E1 driver
Scenario: BTS are configured and working, then the BSC stops working
for some reason (crash or administrative stop).
If the BSC comes back to life, LAPD among other things does not know
about the previous existing TEIs. Instead of ignoring these frames,
we notify the driver that we are seeing frames with unknown TEIs, so
it can try to recover, e.g. by resending the SABM message.
diff --git a/src/input/lapd.c b/src/input/lapd.c
index ddcce5a..0287e14 100644
--- a/src/input/lapd.c
+++ b/src/input/lapd.c
@@ -312,8 +312,9 @@
};
/* General input function for any data received for this LAPD instance */
-uint8_t *lapd_receive(struct lapd_instance *li, uint8_t * data, unsigned int len,
- int *ilen, lapd_mph_type *prim)
+uint8_t *
+lapd_receive(struct lapd_instance *li, uint8_t * data, unsigned int len,
+ int *ilen, lapd_mph_type *prim, int *error)
{
uint8_t sapi, cr, tei, command;
int pf, ns, nr;
@@ -329,12 +330,14 @@
if (len < 2) {
LOGP(DLMI, LOGL_ERROR, "LAPD receive len %d < 2, ignoring\n", len);
+ *error = LAPD_ERR_BAD_LEN;
return NULL;
};
if ((data[0] & 1) != 0 || (data[1] & 1) != 1) {
LOGP(DLMI, LOGL_ERROR, "LAPD address field %x/%x not well formed\n",
data[0], data[1]);
+ *error = LAPD_ERR_BAD_ADDR;
return NULL;
};
@@ -346,6 +349,7 @@
if (len < 3) {
LOGP(DLMI, LOGL_ERROR, "LAPD receive len %d < 3, ignoring\n", len);
+ *error = LAPD_ERR_BAD_LEN;
return NULL;
};
@@ -358,6 +362,7 @@
typ = LAPD_TYPE_I;
if (len < 4) {
LOGP(DLMI, LOGL_ERROR, "LAPD I frame, len %d < 4\n", len);
+ *error = LAPD_ERR_BAD_LEN;
return NULL;
}
ns = data[2] >> 1;
@@ -368,6 +373,7 @@
typ = LAPD_TYPE_S;
if (len < 4) {
LOGP(DLMI, LOGL_ERROR, "LAPD S frame, len %d < 4\n", len);
+ *error = LAPD_ERR_BAD_LEN;
return NULL;
}
nr = data[3] >> 1;
@@ -384,6 +390,7 @@
break;
default:
LOGP(DLMI, LOGL_ERROR, "LAPD unknown S cmd %x\n", data[2]);
+ *error = LAPD_ERR_UNKNOWN_S_CMD;
return NULL;
};
} else if ((data[2] & 3) == 3) {
@@ -416,6 +423,7 @@
default:
LOGP(DLMI, LOGL_ERROR, "LAPD unknown U cmd %x "
"(pf %x data %x)\n", val, pf, data[2]);
+ *error = LAPD_ERR_UNKNOWN_U_CMD;
return NULL;
};
};
@@ -431,6 +439,7 @@
teip = teip_from_tei(li, tei);
if (!teip) {
LOGP(DLMI, LOGL_NOTICE, "LAPD Unknown TEI %u\n", tei);
+ *error = LAPD_ERR_UNKNOWN_TEI;
return NULL;
}
@@ -589,6 +598,7 @@
return contents;
}
+ *error = LAPD_ERR_BAD_CMD;
return NULL;
};