1 files changed, 88 insertions, 0 deletions
diff --git a/ffd/ack.c b/ffd/ack.c
new file mode 100644
index 0000000..0dbb13c
--- /dev/null
+++ b/ffd/ack.c
@@ -0,0 +1,88 @@
+/*
+  Copyright (c) 2012, Matthias Schiffer <mschiffer@universe-factory.net>
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright notice,
+       this list of conditions and the following disclaimer in the documentation
+       and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+
+#include "ffd.h"
+#include "queue.h"
+
+
+static uint8_t acks[1 << 13] = {};
+static ffd_queue_t *ack_requests = NULL;
+static uint16_t nonce = 0;
+
+
+#define SET_ACK(n) do {acks[n >> 3] |= 1 << (n & 7);} while(0)
+#define UNSET_ACK(n) do {acks[n >> 3] &= ~(1 << (n & 7));} while(0)
+#define GET_ACK(n) ((acks[n >> 3] & (1 << (n & 7))) != 0)
+
+
+typedef struct _ack_arg_t {
+	void (*cb)(uint16_t nonce, void *arg);
+	void *arg;
+
+	uint16_t nonce;
+	unsigned interval;
+	unsigned retries;
+} ack_arg_t;
+
+
+void ffd_ack_handle(uint16_t n) {
+	SET_ACK(n);
+}
+
+static void ack_resend(const struct timespec *timeout, void *argp) {
+	ack_arg_t *arg = argp;
+
+	if (GET_ACK(arg->nonce) || !(--arg->retries)) {
+		free(arg);
+		return;
+	}
+
+	arg->cb(arg->nonce, arg->arg);
+
+	ffd_queue_put_delayed(&ack_requests, ack_resend, timeout, arg->interval, arg);
+}
+
+void ffd_ack_request(void (*cb)(uint16_t nonce, void *arg), unsigned interval, unsigned retries, void *arg) {
+	UNSET_ACK(nonce);
+	cb(nonce, arg);
+
+	ack_arg_t *ack_arg = malloc(sizeof(ack_arg_t));
+	ack_arg->cb = cb;
+	ack_arg->arg = arg;
+	ack_arg->nonce = nonce++;
+	ack_arg->interval = interval;
+	ack_arg->retries = retries;
+
+	ffd_queue_put_delayed(&ack_requests, ack_resend, &now, interval, ack_arg);
+}
+
+int ffd_ack_timeout(void) {
+	return ffd_queue_timeout(&ack_requests);
+}
+
+void ffd_ack_run(void) {
+	ffd_queue_run(&ack_requests);
+}