extend the ipa keepalive fsm

The new and improved fsm supports multipe use cases:
1) plain old ipa server/client operation
2) ipa client/server operation with custom send callback (i.e. to bypass
the tx queue)
3) all of the above + custom timeout callback
4) fully generic operation that will pass opaque data to the callbacks

The current code will always kill the fsm and deallocate it upon
timeout, so the timeout callback will now return a value: 1 means the
fsm will be automatically terminated, 0 means no action, which allows
manually stopping/starting the fsm to reuse it.

Change-Id: Ie453fdee8bfd7fc1a3f1ed67ef0331f0abb1d59b

2 files changed, 58 insertions, 9 deletions

diff --git a/include/osmocom/abis/ipa.h b/include/osmocom/abis/ipa.h
index 4f6081f..ff00697 100644
--- a/include/osmocom/abis/ipa.h
+++ b/include/osmocom/abis/ipa.h
@@ -113,7 +113,9 @@ struct ipa_keepalive_params {
 	unsigned int wait_for_resp;
 };
 
-typedef void ipa_keepalive_timeout_cb_t(struct osmo_fsm_inst *fi, void *conn);
+typedef int ipa_keepalive_timeout_cb_t(struct osmo_fsm_inst *fi, void *conn);
+
+typedef void ipa_keepalive_send_cb_t(struct osmo_fsm_inst *fi, void *conn, struct msgb *msg);
 
 struct osmo_fsm_inst *ipa_client_conn_alloc_keepalive_fsm(struct ipa_client_conn *client,
 							  const struct ipa_keepalive_params *params,
@@ -123,12 +125,14 @@ struct osmo_fsm_inst *ipa_server_conn_alloc_keepalive_fsm(struct ipa_server_conn
 							  const struct ipa_keepalive_params *params,
 							  const char *id);
 
-struct osmo_fsm_inst *ipa_keepalive_alloc_server(struct ipa_server_conn *server,
-						 const struct ipa_keepalive_params *params,
-						 const char *id);
+struct osmo_fsm_inst *ipa_generic_conn_alloc_keepalive_fsm(void *ctx, void* data,
+							  const struct ipa_keepalive_params *params,
+							  const char *id);
 
 void ipa_keepalive_fsm_set_timeout_cb(struct osmo_fsm_inst *fi, ipa_keepalive_timeout_cb_t *cb);
 
+void ipa_keepalive_fsm_set_send_cb(struct osmo_fsm_inst *fi, ipa_keepalive_send_cb_t *fn);
+
 void ipa_keepalive_fsm_start(struct osmo_fsm_inst *fi);
 
 void ipa_keepalive_fsm_stop(struct osmo_fsm_inst *fi);
diff --git a/src/input/ipa_keepalive.c b/src/input/ipa_keepalive.c
index 81b5a26..d8eec77 100644
--- a/src/input/ipa_keepalive.c
+++ b/src/input/ipa_keepalive.c
@@ -76,7 +76,9 @@ struct ipa_fsm_priv {
 
 	struct ipa_server_conn *srv_conn;
 	struct ipa_client_conn *client_conn;
+	void *generic;
 	ipa_keepalive_timeout_cb_t *timeout_cb;
+	ipa_keepalive_send_cb_t *send_fn;
 };
 
 static void ipa_ka_init(struct osmo_fsm_inst *fi, uint32_t event, void *data)
@@ -103,11 +105,23 @@ static void ipa_ka_wait_resp_onenter(struct osmo_fsm_inst *fi, uint32_t prev_sta
 	msg = gen_ipa_ping();
 	OSMO_ASSERT(msg);
 
-	if (ifp->srv_conn)
-		ipa_server_conn_send(ifp->srv_conn, msg);
+	if (ifp->send_fn && ifp->generic) {
+		ifp->send_fn(fi, ifp->generic, msg);
+		return;
+	}
+
+	if (ifp->srv_conn) {
+		if (ifp->send_fn)
+			ifp->send_fn(fi, ifp->srv_conn, msg);
+		else
+			ipa_server_conn_send(ifp->srv_conn, msg);
+	}
 	else {
 		OSMO_ASSERT(ifp->client_conn);
-		ipa_client_conn_send(ifp->client_conn, msg);
+		if (ifp->send_fn)
+			ifp->send_fn(fi, ifp->client_conn, msg);
+		else
+			ipa_client_conn_send(ifp->client_conn, msg);
 	}
 }
 
@@ -140,10 +154,12 @@ static int ipa_ka_fsm_timer_cb(struct osmo_fsm_inst *fi)
 		/* PONG not received within time */
 		if (ifp->srv_conn)
 			conn = ifp->srv_conn;
-		else
+		else if (ifp->client_conn)
 			conn = ifp->client_conn;
+		else
+			conn = ifp->generic;
 		if (ifp->timeout_cb)
-			ifp->timeout_cb(fi, conn);
+			return ifp->timeout_cb(fi, conn);
 		/* ask fsm core to terminate us */
 		return 1;
 	default:
@@ -261,6 +277,27 @@ struct osmo_fsm_inst *ipa_server_conn_alloc_keepalive_fsm(struct ipa_server_conn
 	return fi;
 }
 
+/*! Create a new instance of an IPA keepalive FSM: Periodically transmit PING and expect PONG.
+ *  \param[in] ctx Talloc context.
+ *  \param[in] data Data to pass to write/timeout cb.
+ *  \param[in] params Parameters describing the keepalive FSM time-outs.
+ *  \param[in] id String used as identifier for the FSM.
+ *  \returns pointer to the newly-created FSM instance; NULL in case of error. */
+struct osmo_fsm_inst *ipa_generic_conn_alloc_keepalive_fsm(void *ctx, void* data,
+							   const struct ipa_keepalive_params *params,
+							   const char *id)
+{
+	struct osmo_fsm_inst *fi;
+	struct ipa_fsm_priv *ifp;
+	
+	fi = __ipa_conn_alloc_keepalive_fsm(ctx, params, id);
+	if (!fi)
+		return NULL;
+	ifp = fi->priv;
+	ifp->generic = data;
+	return fi;
+}
+
 /*! Set a timeout call-back which is to be called once the peer doesn't respond anymore */
 void ipa_keepalive_fsm_set_timeout_cb(struct osmo_fsm_inst *fi, ipa_keepalive_timeout_cb_t *cb)
 {
@@ -269,6 +306,14 @@ void ipa_keepalive_fsm_set_timeout_cb(struct osmo_fsm_inst *fi, ipa_keepalive_ti
 	ifp->timeout_cb = cb;
 }
 
+/*! Set a custom send callback for sending pings */
+void ipa_keepalive_fsm_set_send_cb(struct osmo_fsm_inst *fi, ipa_keepalive_send_cb_t *fn)
+{
+	struct ipa_fsm_priv *ifp = fi->priv;
+	OSMO_ASSERT(fi->fsm == &ipa_keepalive_fsm);
+	ifp->send_fn = fn;
+}
+
 /*! Inform IPA Keepalive FSM that a PONG has been received. */
 void ipa_keepalive_fsm_pong_received(struct osmo_fsm_inst *fi)
 {