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+/* Quagga pselect support -- header
+ * Copyright (C) 2009 Chris Hall (GMCH), Highwayman
+ *
+ * This file is part of GNU Zebra.
+ *
+ * GNU Zebra 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 2, or (at your
+ * option) any later version.
+ *
+ * GNU Zebra 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 GNU Zebra; see the file COPYING. If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef _ZEBRA_QPSELECT_H
+#define _ZEBRA_QPSELECT_H
+
+#include <sys/select.h>
+#include <errno.h>
+
+#include "zassert.h"
+#include "qtime.h"
+#include "vector.h"
+
+#ifndef Inline
+#define Inline static inline
+#endif
+
+/*==============================================================================
+ * Quagga pselect -- qps_xxxx
+ *
+ * Here and in qpselect.c is a data structure for managing multiple file
+ * descriptors and running pselect to wait for I/O activity and to multiplex
+ * between the file descriptors.
+ */
+
+enum qps_mnum /* "mode" numbers: error/read/write */
+{
+ qps_mnum_first = 0,
+
+ qps_error_mnum = 0,
+ qps_read_mnum = 1,
+ qps_write_mnum = 2,
+
+ qps_mnum_count = 3
+} ;
+
+typedef enum qps_mnum qps_mnum_t ;
+
+#define qps_mbit(mnum) (1 << mnum)
+
+enum qps_mbits /* "mode" bits: error/read/write */
+{
+ qps_error_mbit = qps_mbit(qps_error_mnum),
+ qps_read_mbit = qps_mbit(qps_read_mnum),
+ qps_write_mbit = qps_mbit(qps_write_mnum),
+
+ qps_all_mbits = qps_mbit(qps_mnum_count) - 1
+} ;
+
+typedef enum qps_mbits qps_mbit_t ;
+
+/* "fd_undef" -- used when fd is undefined */
+enum { fd_undef = -1 } ;
+
+/* Forward references */
+typedef struct qps_selection* qps_selection ;
+typedef struct qps_file* qps_file ;
+
+/*==============================================================================
+ * fd_super_set.
+ *
+ * To speed up scanning of large fd_set's this structure overlays a 32-bit
+ * word and a byte array over the (assumed) fd_set bit vector.
+ *
+ * There is no guarantee that FD_SETSIZE is a multiple of 32 (or of 8, for
+ * that matter) -- so some care must be taken.
+ */
+
+typedef uint32_t fd_word_t ;
+
+#define FD_WORD_BITS 32
+#define FD_WORD_BYTES (FD_WORD_BITS / 8)
+
+CONFIRM(FD_WORD_BITS == (FD_WORD_BYTES * 8)) ; /* for completeness */
+
+#define FD_SUPER_SET_WORD_SIZE ((FD_SETSIZE + FD_WORD_BITS - 1) / FD_WORD_BITS)
+#define FD_SUPER_SET_BYTE_SIZE (FD_SUPER_SET_WORD_SIZE * FD_WORD_BYTES)
+
+/* Make sure that the overlay is at least as big as the fd_set ! */
+CONFIRM(FD_SUPER_SET_BYTE_SIZE >= sizeof(fd_set)) ;
+
+typedef union /* see qps_make_super_set_map() */
+{
+ fd_word_t words[FD_SUPER_SET_WORD_SIZE] ;
+ uint8_t bytes[FD_SUPER_SET_BYTE_SIZE] ;
+ fd_set fdset ;
+} fd_super_set ;
+
+/* Make sure that the fd_super_set is an exact number of fd_word_t words */
+CONFIRM(sizeof(fd_super_set) == (FD_SUPER_SET_WORD_SIZE * FD_WORD_BYTES)) ;
+
+/*==============================================================================
+ * Action function.
+ *
+ * Each file has three action functions, to be called in qps_dispatch_next()
+ * when pselect() has reported error/read/write for the file.
+ *
+ * For further discussion, see: qps_file_init.
+ */
+
+typedef void qps_action(qps_file qf, void* file_info) ;
+
+/*==============================================================================
+ * Data Structures.
+ */
+
+typedef fd_super_set fd_full_set[qps_mnum_count] ;
+
+struct qps_selection
+{
+ int fd_count ; /* number of fds we are looking after */
+ int fd_direct ; /* direct lookup in vector or not */
+
+ struct vector files ; /* mapping fd to qps_file */
+
+ int fd_last ; /* highest numbered fd; -1 => none at all */
+ int enabled_count[qps_mnum_count] ; /* no. enabled fds in each mode */
+ fd_full_set enabled ; /* bit vectors for pselect enabled stuff */
+
+ int tried_fd_last ; /* highest numbered fd on last pselect */
+ int tried_count[qps_mnum_count] ; /* enabled_count on last pselect */
+ fd_full_set results ; /* last set of results from pselect */
+
+ int pend_count ; /* results pending (if any) */
+ qps_mnum_t pend_mnum ; /* error/read/write mode pending (if any) */
+ int pend_fd ; /* fd pending (if any) */
+
+ int signum ; /* signal that sigmask is enabling -- 0 => none */
+ sigset_t sigmask ; /* sigmask to use for duration of pselect */
+} ;
+
+struct qps_file
+{
+ qps_selection selection ;
+
+ void* file_info ;
+ int fd ;
+
+ qps_mbit_t enabled_bits ;
+
+ qps_action* actions[qps_mnum_count] ;
+} ;
+
+/*==============================================================================
+ * qps_selection handling
+ */
+
+extern void
+qps_start_up(void) ;
+
+extern qps_selection
+qps_selection_init_new(qps_selection qps) ;
+
+extern void
+qps_add_file(qps_selection qps, qps_file qf, int fd, void* file_info) ;
+
+extern void
+qps_remove_file(qps_file qf) ;
+
+extern qps_file
+qps_selection_ream(qps_selection qps, int free_structure) ;
+
+/* Ream out selection and free the selection structure. */
+#define qps_selection_ream_free(qps) qps_selection_ream(qps, 1)
+/* Ream out selection but keep the selection structure. */
+#define qps_selection_ream_keep(qps) qps_selection_ream(qps, 0)
+
+extern void
+qps_set_signal(qps_selection qps, int signum, sigset_t sigmask) ;
+
+extern int
+qps_pselect(qps_selection qps, qtime_mono_t timeout) ;
+
+extern int
+qps_dispatch_next(qps_selection qps) ;
+
+/*==============================================================================
+ * qps_file structure handling
+ */
+
+extern qps_file
+qps_file_init_new(qps_file qf, qps_file template) ;
+
+extern qps_file
+qps_file_free(qps_file qf) ;
+
+extern void
+qps_enable_mode(qps_file qf, qps_mnum_t mnum, qps_action* action) ;
+
+extern void
+qps_set_action(qps_file qf, qps_mnum_t mnum, qps_action* action) ;
+
+extern void
+qps_disable_modes(qps_file qf, qps_mbit_t mbits) ;
+
+Inline void*
+qps_file_info(qps_file qf)
+{
+ return qf->file_info ;
+} ;
+
+Inline int
+qps_file_fd(qps_file qf)
+{
+ return qf->fd ;
+} ;
+
+Inline int
+qps_file_unset_fd(qps_file qf)
+{
+ int fd = qf->fd ;
+ qf->fd = fd_undef ;
+
+ return fd ;
+} ;
+
+Inline void
+qps_set_file_info(qps_file qf, void* info)
+{
+ qf->file_info = info ;
+} ;
+
+#endif /* _ZEBRA_QPSELECT_H */
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