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Diffstat (limited to 'lib/qpselect.h')
| -rw-r--r-- | lib/qpselect.h | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/lib/qpselect.h b/lib/qpselect.h new file mode 100644 index 00000000..1e67d174 --- /dev/null +++ b/lib/qpselect.h @@ -0,0 +1,208 @@ +/* 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 ; + +/* 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 we are looking after */ + 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 + */ + +qps_selection +qps_selection_init_new(qps_selection qps) ; + +void +qps_add_file(qps_selection qps, qps_file qf, int fd, void* file_info) ; + +void +qps_remove_file(qps_file qf) ; + +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) + +void +qps_set_signal(qps_selection qps, int signum, sigset_t sigmask) ; + +int +qps_pselect(qps_selection qps, qtime_mono_t timeout) ; + +int +qps_dispatch_next(qps_selection qps) ; + +/*============================================================================== + * qps_file structure handling + */ + +qps_file +qps_file_init_new(qps_file qf, qps_file template) ; + +void +qps_file_free(qps_file qf) ; + +void +qps_enable_mode(qps_file qf, qps_mnum_t mnum, qps_action* action) ; + +void +qps_set_action(qps_file qf, qps_mnum_t mnum, qps_action* action) ; + +void +qps_disable_modes(qps_file qf, qps_mbit_t mbits) ; + +#endif /* _ZEBRA_QPSELECT_H */ |