1 files changed, 63 insertions, 0 deletions
diff --git a/src/lib/cap.h b/src/lib/cap.h
new file mode 100644
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+++ b/src/lib/cap.h
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+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Link capacity estimation
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#ifndef OUROBOROS_LIB_CAP_H
+#define OUROBOROS_LIB_CAP_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define CAP_ALIGN 64
+
+struct cap_est {
+        uint64_t c_pkt;  /* total packets enqueued (relaxed)  */
+        uint64_t c_byt;  /* total bytes enqueued (relaxed)    */
+        uint64_t c_idl;  /* times ring seen empty (relaxed)   */
+
+        uint64_t t_gate; /* last window close (ns)            */
+        uint64_t t_last; /* last update, to spot a gap (ns)   */
+        uint8_t  busy;   /* close in progress (try-lock)      */
+
+        uint64_t t0;     /* window start (ns), 0 = no window  */
+        uint64_t q0;     /* ring occupancy at window start    */
+        uint64_t pkt0;   /* c_pkt snapshot at window start    */
+        uint64_t byt0;   /* c_byt snapshot at window start    */
+        uint64_t idl0;   /* c_idl snapshot at window start    */
+        uint64_t rate;   /* filtered drain rate (bytes/s)     */
+
+        uint64_t est;    /* published estimate (bytes/s)      */
+} __attribute__((aligned(CAP_ALIGN)));
+
+void     cap_clear(struct cap_est * e);
+
+void     cap_update(struct cap_est * e,
+                    size_t           qlen,
+                    size_t           len);
+
+void     cap_update_at(struct cap_est * e,
+                       size_t           qlen,
+                       size_t           len,
+                       uint64_t         now);
+
+uint64_t cap_rate(const struct cap_est * e);
+
+#endif /* OUROBOROS_LIB_CAP_H */