RBS2000: Move SABM re-transmit logic into LAPD code
This means we now can support multiple LAPD links
diff --git a/openbsc/src/input/lapd.c b/openbsc/src/input/lapd.c
index 0c3b469..1212fb3 100644
--- a/openbsc/src/input/lapd.c
+++ b/openbsc/src/input/lapd.c
@@ -1,9 +1,9 @@
/* OpenBSC minimal LAPD implementation */
/* (C) 2009 by oystein@homelien.no
- * (C) 2011 by Harald Welte <laforge@gnumonks.org>
* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2010 by Digium and Matthew Fredrickson <creslin@digium.com>
+ * (C) 2011 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
@@ -23,6 +23,12 @@
*
*/
+/* TODO:
+ * detect RR timeout and set SAP state back to SABM_RETRANSMIT
+ * use of value_string
+ * further code cleanup (spaghetti)
+ */
+
#include <stdio.h>
#include <string.h>
#include <assert.h>
@@ -33,13 +39,14 @@
#include <osmocore/linuxlist.h>
#include <osmocore/talloc.h>
#include <osmocore/msgb.h>
+#include <osmocore/timer.h>
#include <openbsc/debug.h>
+#define SABM_INTERVAL 0, 300000
+
typedef enum {
LAPD_TEI_NONE = 0,
-
LAPD_TEI_ASSIGNED,
-
LAPD_TEI_ACTIVE,
} lapd_tei_state;
@@ -93,10 +100,24 @@
};
+enum lapd_sap_state {
+ SAP_STATE_INACTIVE,
+ SAP_STATE_SABM_RETRANS,
+ SAP_STATE_ACTIVE,
+};
+
+const char *lapd_sap_states[] = {
+ "INACTIVE",
+ "SABM_RETRANS",
+ "ACTIVE",
+};
+
const char *lapd_msg_types = "?ISU";
+/* structure representing an allocated TEI within a LAPD instance */
struct lapd_tei {
struct llist_head list;
+ struct lapd_instance *li;
uint8_t tei;
/* A valid N(R) value is one that is in the range V(A) ≤ N(R) ≤ V(S). */
@@ -104,6 +125,19 @@
int va; /* last acked by peer */
int vr; /* next expected to be received */
lapd_tei_state state;
+
+ struct llist_head sap_list;
+};
+
+/* Structure representing a SAP within a TEI. We use this for TE-mode to
+ * re-transmit SABM */
+struct lapd_sap {
+ struct llist_head list;
+ struct lapd_tei *tei;
+ uint8_t sapi;
+ enum lapd_sap_state state;
+
+ struct timer_list sabme_timer; /* timer to re-transmit SABM message */
};
/* 3.5.2.2 Send state variable V(S)
@@ -142,6 +176,7 @@
* correctly received all I frames numbered up to and including N(R) − 1.
*/
+/* Resolve TEI structure from given numeric TEI */
static struct lapd_tei *teip_from_tei(struct lapd_instance *li, uint8_t tei)
{
struct lapd_tei *lt;
@@ -155,28 +190,87 @@
static void lapd_tei_set_state(struct lapd_tei *teip, int newstate)
{
- DEBUGP(DMI, "state change on tei %d: %s -> %s\n", teip->tei,
+ DEBUGP(DMI, "state change on TEI %d: %s -> %s\n", teip->tei,
lapd_tei_states[teip->state], lapd_tei_states[newstate]);
teip->state = newstate;
};
-
-int lapd_tei_alloc(struct lapd_instance *li, uint8_t tei)
+/* Allocate a new TEI */
+struct lapd_tei *lapd_tei_alloc(struct lapd_instance *li, uint8_t tei)
{
struct lapd_tei *teip;
teip = talloc_zero(li, struct lapd_tei);
if (!teip)
- return -ENOMEM;
+ return NULL;
+ teip->li = li;
teip->tei = tei;
llist_add(&teip->list, &li->tei_list);
+ INIT_LLIST_HEAD(&teip->sap_list);
lapd_tei_set_state(teip, LAPD_TEI_ASSIGNED);
- return 0;
+ return teip;
}
+/* Find a SAP within a given TEI */
+static struct lapd_sap *lapd_sap_find(struct lapd_tei *teip, uint8_t sapi)
+{
+ struct lapd_sap *sap;
+
+ llist_for_each_entry(sap, &teip->sap_list, list) {
+ if (sap->sapi == sapi)
+ return sap;
+ }
+
+ return NULL;
+}
+
+static void sabme_timer_cb(void *_sap);
+
+/* Allocate a new SAP within a given TEI */
+static struct lapd_sap *lapd_sap_alloc(struct lapd_tei *teip, uint8_t sapi)
+{
+ struct lapd_sap *sap = talloc_zero(teip, struct lapd_sap);
+
+ LOGP(DMI, LOGL_INFO, "Allocating SAP for SAPI=%u / TEI=%u\n",
+ sapi, teip->tei);
+
+ sap->sapi = sapi;
+ sap->tei = teip;
+ sap->sabme_timer.cb = &sabme_timer_cb;
+ sap->sabme_timer.data = sap;
+
+ llist_add(&sap->list, &teip->sap_list);
+
+ return sap;
+}
+
+static void lapd_sap_set_state(struct lapd_tei *teip, uint8_t sapi,
+ enum lapd_sap_state newstate)
+{
+ struct lapd_sap *sap = lapd_sap_find(teip, sapi);
+ if (!sap)
+ return;
+
+ DEBUGP(DMI, "state change on TEI %u / SAPI %u: %s -> %s\n", teip->tei,
+ sapi, lapd_sap_states[sap->state], lapd_sap_states[newstate]);
+ switch (sap->state) {
+ case SAP_STATE_SABM_RETRANS:
+ if (newstate != SAP_STATE_SABM_RETRANS)
+ bsc_del_timer(&sap->sabme_timer);
+ break;
+ default:
+ if (newstate == SAP_STATE_SABM_RETRANS)
+ bsc_schedule_timer(&sap->sabme_timer, SABM_INTERVAL);
+ break;
+ }
+
+ sap->state = newstate;
+};
+
+/* Input function into TEI manager */
static void lapd_tei_receive(struct lapd_instance *li, uint8_t *data, int len)
{
uint8_t entity = data[0];
@@ -214,6 +308,7 @@
};
};
+/* 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)
{
@@ -391,6 +486,7 @@
teip->vr = 0;
teip->va = 0;
lapd_tei_set_state(teip, LAPD_TEI_ACTIVE);
+ lapd_sap_set_state(teip, sapi, SAP_STATE_ACTIVE);
*prim = LAPD_MPH_ACTIVATE_IND;
break;
case LAPD_CMD_RR:
@@ -478,7 +574,8 @@
return NULL;
};
-int lapd_send_sabm(struct lapd_instance *li, uint8_t tei, uint8_t sapi)
+/* low-level function to send a single SABM message */
+static int lapd_send_sabm(struct lapd_instance *li, uint8_t tei, uint8_t sapi)
{
struct msgb *msg = msgb_alloc_headroom(1024, 128, "LAPD SABM");
if (!msg)
@@ -486,10 +583,6 @@
DEBUGP(DMI, "Sending SABM for TEI=%u, SAPI=%u\n", tei, sapi);
- /* make sure we know the TEI at the time the response comes in */
- if (!teip_from_tei(li, tei))
- lapd_tei_alloc(li, tei);
-
msgb_put_u8(msg, (sapi << 2) | (li->network_side ? 2 : 0));
msgb_put_u8(msg, (tei << 1) | 1);
msgb_put_u8(msg, 0x7F);
@@ -501,6 +594,60 @@
return 0;
}
+/* timer call-back function for SABM re-transmission */
+static void sabme_timer_cb(void *_sap)
+{
+ struct lapd_sap *sap = _sap;
+
+ lapd_send_sabm(sap->tei->li, sap->tei->tei, sap->sapi);
+
+ bsc_schedule_timer(&sap->sabme_timer, SABM_INTERVAL);
+}
+
+/* Start a (user-side) SAP for the specified TEI/SAPI on the LAPD instance */
+int lapd_sap_start(struct lapd_instance *li, uint8_t tei, uint8_t sapi)
+{
+ struct lapd_sap *sap;
+ struct lapd_tei *teip;
+
+ teip = teip_from_tei(li, tei);
+ if (!teip)
+ teip = lapd_tei_alloc(li, tei);
+
+ sap = lapd_sap_find(teip, sapi);
+ if (sap)
+ return -EEXIST;
+
+ sap = lapd_sap_alloc(teip, sapi);
+
+ lapd_sap_set_state(teip, sapi, SAP_STATE_SABM_RETRANS);
+
+ return 0;
+}
+
+/* Stop a (user-side) SAP for the specified TEI/SAPI on the LAPD instance */
+int lapd_sap_stop(struct lapd_instance *li, uint8_t tei, uint8_t sapi)
+{
+ struct lapd_tei *teip;
+ struct lapd_sap *sap;
+
+ teip = teip_from_tei(li, tei);
+ if (!teip)
+ return -ENODEV;
+
+ sap = lapd_sap_find(teip, sapi);
+ if (!sap)
+ return -ENODEV;
+
+ bsc_del_timer(&sap->sabme_timer);
+
+ llist_del(&sap->list);
+ talloc_free(sap);
+
+ return 0;
+}
+
+/* Transmit Data (I-Frame) on the given LAPD Instance / TEI / SAPI */
void lapd_transmit(struct lapd_instance *li, uint8_t tei, uint8_t sapi,
uint8_t *data, unsigned int len)
{
@@ -530,6 +677,7 @@
li->transmit_cb(buf, len, li->cbdata);
};
+/* Allocate a new LAPD instance */
struct lapd_instance *lapd_instance_alloc(int network_side,
void (*tx_cb)(uint8_t *data, int len,
void *cbdata), void *cbdata)