1 files changed, 113 insertions, 0 deletions
diff --git a/src/knot/common/fdset.h b/src/knot/common/fdset.h
new file mode 100644
index 0000000..a5623f7
--- /dev/null
+++ b/src/knot/common/fdset.h
@@ -0,0 +1,113 @@
+/*  Copyright (C) 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*!
+ * \brief I/O multiplexing with context and timeouts for each fd.
+ */
+
+#pragma once
+
+#include <stddef.h>
+#include <poll.h>
+#include <sys/time.h>
+#include <signal.h>
+
+#define FDSET_INIT_SIZE 256 /* Resize step. */
+
+/*! \brief Set of filedescriptors with associated context and timeouts. */
+typedef struct fdset {
+	unsigned n;          /*!< Active fds. */
+	unsigned size;       /*!< Array size (allocated). */
+	void* *ctx;          /*!< Context for each fd. */
+	struct pollfd *pfd;  /*!< poll state for each fd */
+	time_t *timeout;     /*!< Timeout for each fd (seconds precision). */
+} fdset_t;
+
+/*! \brief Mark-and-sweep state. */
+enum fdset_sweep_state {
+	FDSET_KEEP,
+	FDSET_SWEEP
+};
+
+/*! \brief Sweep callback (set, index, data) */
+typedef enum fdset_sweep_state (*fdset_sweep_cb_t)(fdset_t*, int, void*);
+
+/*!
+ * \brief Initialize fdset to given size.
+ */
+int fdset_init(fdset_t *set, unsigned size);
+
+/*!
+ * \brief Destroy FDSET.
+ *
+ * \retval 0 if successful.
+ * \retval -1 on error.
+ */
+int fdset_clear(fdset_t* set);
+
+/*!
+ * \brief Add file descriptor to watched set.
+ *
+ * \param set Target set.
+ * \param fd Added file descriptor.
+ * \param events Mask of watched events.
+ * \param ctx Context (optional).
+ *
+ * \retval index of the added fd if successful.
+ * \retval -1 on errors.
+ */
+int fdset_add(fdset_t *set, int fd, unsigned events, void *ctx);
+
+/*!
+ * \brief Remove file descriptor from watched set.
+ *
+ * \param set Target set.
+ * \param i Index of the removed fd.
+ *
+ * \retval 0 if successful.
+ * \retval -1 on errors.
+ */
+int fdset_remove(fdset_t *set, unsigned i);
+
+/*!
+ * \brief Set file descriptor watchdog interval.
+ *
+ * Set time (interval from now) after which the associated file descriptor
+ * should be sweeped (see fdset_sweep). Good example is setting a grace period
+ * of N seconds between socket activity. If socket is not active within
+ * <now, now + interval>, it is sweeped and potentially closed.
+ *
+ * \param set Target set.
+ * \param i Index for the file descriptor.
+ * \param interval Allowed interval without activity (seconds).
+ *                 -1 disables watchdog timer
+ *
+ * \retval 0 if successful.
+ * \retval -1 on errors.
+ */
+int fdset_set_watchdog(fdset_t* set, int i, int interval);
+
+/*!
+ * \brief Sweep file descriptors with exceeding inactivity period.
+ *
+ * \param set Target set.
+ * \param cb Callback for sweeped descriptors.
+ * \param data Pointer to extra data.
+ *
+ * \retval number of sweeped descriptors.
+ * \retval -1 on errors.
+ */
+int fdset_sweep(fdset_t* set, fdset_sweep_cb_t cb, void *data);