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/e1_input.c b/src/e1_input.c
index 701152c..b8b0130 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -544,6 +544,7 @@
if (!link)
return -EINVAL;
+ isd.line = ts->line;
isd.link_type = link->type;
isd.trx = link->trx;
isd.tei = tei;
diff --git a/src/input/dahdi.c b/src/input/dahdi.c
index 3adfa18..0eac0ab 100644
--- a/src/input/dahdi.c
+++ b/src/input/dahdi.c
@@ -93,7 +93,7 @@
struct msgb *msg = msgb_alloc(TS1_ALLOC_SIZE, "DAHDI TS1");
lapd_mph_type prim;
unsigned int sapi, tei;
- int ilen, ret;
+ int ilen, ret, error = 0;
uint8_t *idata;
if (!msg)
@@ -115,9 +115,21 @@
DEBUGP(DLMI, "<= len = %d, sapi(%d) tei(%d)", ret, sapi, tei);
- idata = lapd_receive(e1i_ts->driver.dahdi.lapd, msg->data, msg->len, &ilen, &prim);
- if (!idata && prim == 0)
- return -EIO;
+ idata = lapd_receive(e1i_ts->driver.dahdi.lapd, msg->data, msg->len, &ilen, &prim, &error);
+ if (!idata) {
+ switch(error) {
+ case LAPD_ERR_UNKNOWN_TEI:
+ /* We don't know about this TEI, probably the BSC
+ * lost local states (it crashed or it was stopped),
+ * notify the driver to see if it can do anything to
+ * recover the existing signalling links with the BTS.
+ */
+ e1inp_event(e1i_ts, S_INP_TEI_UNKNOWN, tei, sapi);
+ return -EIO;
+ }
+ if (prim == 0)
+ return -EIO;
+ }
msgb_pull(msg, 2);
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;
};