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Diffstat (limited to 'include/haproxy/fd-t.h')
| -rw-r--r-- | include/haproxy/fd-t.h | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/include/haproxy/fd-t.h b/include/haproxy/fd-t.h new file mode 100644 index 0000000..c5e94cb --- /dev/null +++ b/include/haproxy/fd-t.h @@ -0,0 +1,251 @@ +/* + * include/haproxy/fd-t.h + * File descriptors states - check src/fd.c for explanations. + * + * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation, version 2.1 + * exclusively. + * + * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef _HAPROXY_FD_T_H +#define _HAPROXY_FD_T_H + +#include <haproxy/api-t.h> +#include <haproxy/port_range-t.h> +#include <haproxy/show_flags-t.h> + +/* Direction for each FD event update */ +enum { + DIR_RD=0, + DIR_WR=1, +}; + + +/* fdtab[].state is a composite state describing what is known about the FD. + * For now, the following information are stored in it: + * - event configuration and status for each direction (R,W) split into + * active, ready, shutdown categories (FD_EV_*). These are known by their + * bit values as well so that test-and-set bit operations are possible. + * + * - last known polling status (FD_POLL_*). For ease of troubleshooting, + * avoid visually mixing these ones with the other ones above. 3 of these + * flags are updated on each poll() report (FD_POLL_IN, FD_POLL_OUT, + * FD_POLL_PRI). FD_POLL_HUP and FD_POLL_ERR are "sticky" in that once they + * are reported, they will not be cleared until the FD is closed. + */ + +/* bits positions for a few flags */ +#define FD_EV_ACTIVE_R_BIT 0 +#define FD_EV_READY_R_BIT 1 +#define FD_EV_SHUT_R_BIT 2 +/* unused: 3 */ + +#define FD_EV_ACTIVE_W_BIT 4 +#define FD_EV_READY_W_BIT 5 +#define FD_EV_SHUT_W_BIT 6 +#define FD_EV_ERR_RW_BIT 7 + +#define FD_POLL_IN_BIT 8 +#define FD_POLL_PRI_BIT 9 +#define FD_POLL_OUT_BIT 10 +#define FD_POLL_ERR_BIT 11 +#define FD_POLL_HUP_BIT 12 + +/* info/config bits */ +#define FD_LINGER_RISK_BIT 16 /* must kill lingering before closing */ +#define FD_CLONED_BIT 17 /* cloned socket, requires EPOLL_CTL_DEL on close */ +#define FD_INITIALIZED_BIT 18 /* init phase was done (e.g. output pipe set non-blocking) */ +#define FD_ET_POSSIBLE_BIT 19 /* edge-triggered is possible on this FD */ +#define FD_EXPORTED_BIT 20 /* FD is exported and must not be closed */ +#define FD_EXCL_SYSCALL_BIT 21 /* a syscall claims exclusivity on this FD */ +#define FD_DISOWN_BIT 22 /* this fd will be closed by some external code */ +#define FD_MUST_CLOSE_BIT 23 /* this fd will be closed by some external code */ + + +/* and flag values */ +#define FD_EV_ACTIVE_R (1U << FD_EV_ACTIVE_R_BIT) +#define FD_EV_ACTIVE_W (1U << FD_EV_ACTIVE_W_BIT) +#define FD_EV_ACTIVE_RW (FD_EV_ACTIVE_R | FD_EV_ACTIVE_W) + +#define FD_EV_READY_R (1U << FD_EV_READY_R_BIT) +#define FD_EV_READY_W (1U << FD_EV_READY_W_BIT) +#define FD_EV_READY_RW (FD_EV_READY_R | FD_EV_READY_W) + +/* note that when FD_EV_SHUT is set, ACTIVE and READY are cleared */ +#define FD_EV_SHUT_R (1U << FD_EV_SHUT_R_BIT) +#define FD_EV_SHUT_W (1U << FD_EV_SHUT_W_BIT) +#define FD_EV_SHUT_RW (FD_EV_SHUT_R | FD_EV_SHUT_W) + +/* note that when FD_EV_ERR is set, SHUT is also set. Also, ERR is for both + * directions at once (write error, socket dead, etc). + */ +#define FD_EV_ERR_RW (1U << FD_EV_ERR_RW_BIT) + +/* mask covering all use cases above */ +#define FD_EV_ANY (FD_EV_ACTIVE_RW | FD_EV_READY_RW | FD_EV_SHUT_RW | FD_EV_ERR_RW) + +/* polling status */ +#define FD_POLL_IN (1U << FD_POLL_IN_BIT) +#define FD_POLL_PRI (1U << FD_POLL_PRI_BIT) +#define FD_POLL_OUT (1U << FD_POLL_OUT_BIT) +#define FD_POLL_ERR (1U << FD_POLL_ERR_BIT) +#define FD_POLL_HUP (1U << FD_POLL_HUP_BIT) +#define FD_POLL_UPDT_MASK (FD_POLL_IN | FD_POLL_PRI | FD_POLL_OUT) +#define FD_POLL_ANY_MASK (FD_POLL_IN | FD_POLL_PRI | FD_POLL_OUT | FD_POLL_ERR | FD_POLL_HUP) + +/* information/configuration flags */ +#define FD_LINGER_RISK (1U << FD_LINGER_RISK_BIT) +#define FD_CLONED (1U << FD_CLONED_BIT) +#define FD_INITIALIZED (1U << FD_INITIALIZED_BIT) +#define FD_ET_POSSIBLE (1U << FD_ET_POSSIBLE_BIT) +#define FD_EXPORTED (1U << FD_EXPORTED_BIT) +#define FD_EXCL_SYSCALL (1U << FD_EXCL_SYSCALL_BIT) +#define FD_DISOWN (1U << FD_DISOWN_BIT) +#define FD_MUST_CLOSE (1U << FD_MUST_CLOSE_BIT) + +/* This function is used to report flags in debugging tools. Please reflect + * below any single-bit flag addition above in the same order via the + * __APPEND_FLAG macro. The new end of the buffer is returned. + */ +static forceinline char *fd_show_flags(char *buf, size_t len, const char *delim, uint flg) +{ +#define _(f, ...) __APPEND_FLAG(buf, len, delim, flg, f, #f, __VA_ARGS__) + /* prologue */ + _(0); + /* flags */ + _(FD_EV_ACTIVE_R, _(FD_EV_ACTIVE_W, _(FD_EV_READY_R, _(FD_EV_READY_W, + _(FD_EV_SHUT_R, _(FD_EV_SHUT_W, _(FD_EV_ERR_RW, _(FD_POLL_IN, + _(FD_POLL_PRI, _(FD_POLL_OUT, _(FD_POLL_ERR, _(FD_POLL_HUP, + _(FD_LINGER_RISK, _(FD_CLONED, _(FD_INITIALIZED, _(FD_ET_POSSIBLE, + _(FD_EXPORTED, _(FD_EXCL_SYSCALL, _(FD_DISOWN))))))))))))))))))); + /* epilogue */ + _(~0U); + return buf; +#undef _ +} + +/* FD update status after fd_update_events() */ +enum { + FD_UPDT_DONE = 0, // update done, nothing else to be done + FD_UPDT_CLOSED, // FD was closed + FD_UPDT_MIGRATED, // FD was migrated, ignore it now +}; + +/* This is the value used to mark a file descriptor as dead. This value is + * negative, this is important so that tests on fd < 0 properly match. It + * also has the nice property of being highly negative but neither overflowing + * nor changing sign on 32-bit machines when multiplied by sizeof(fdtab). + * This ensures that any unexpected dereference of such an uninitialized + * file descriptor will lead to so large a dereference that it will crash + * the process at the exact location of the bug with a clean stack trace + * instead of causing silent manipulation of other FDs. And it's readable + * when found in a dump. + */ +#define DEAD_FD_MAGIC 0xFDDEADFD + +/* fdlist_entry: entry used by the fd cache. + * >= 0 means we're in the cache and gives the FD of the next in the cache, + * -1 means we're in the cache and the last element, + * -2 means the entry is locked, + * <= -3 means not in the cache, and next element is -4-fd + * + * It must remain 8-aligned so that aligned CAS operations may be done on both + * entries at once. + */ +struct fdlist_entry { + int next; + int prev; +} ALIGNED(8); + +/* head of the fd cache, per-group */ +struct fdlist { + int first; + int last; +} ALIGNED(64); + +/* info about one given fd. Note: only align on cache lines when using threads; + * 32-bit small archs can put everything in 32-bytes when threads are disabled. + * refc_tgid is an atomic 32-bit composite value made of 16 higher bits + * containing a refcount on tgid and the running_mask, and 16 lower bits + * containing a thread group ID and a lock bit on the 16th. The tgid may only + * be changed when refc is zero and running may only be checked/changed when + * refc is held and shows the reader is alone. An FD with tgid zero belongs to + * nobody. + */ +struct fdtab { + unsigned long running_mask; /* mask of thread IDs currently using the fd */ + unsigned long thread_mask; /* mask of thread IDs authorized to process the fd */ + unsigned long update_mask; /* mask of thread IDs having an update for fd */ + struct fdlist_entry update; /* Entry in the global update list */ + void (*iocb)(int fd); /* I/O handler */ + void *owner; /* the connection or listener associated with this fd, NULL if closed */ + unsigned int state; /* FD state for read and write directions (FD_EV_*) + FD_POLL_* */ + unsigned int refc_tgid; /* refcounted tgid, updated atomically */ +#ifdef DEBUG_FD + unsigned int event_count; /* number of events reported */ +#endif +} THREAD_ALIGNED(64); + +/* polled mask, one bit per thread and per direction for each FD */ +struct polled_mask { + unsigned long poll_recv; + unsigned long poll_send; +}; + +/* less often used information */ +struct fdinfo { + struct port_range *port_range; /* optional port range to bind to */ + int local_port; /* optional local port */ +}; + +/* + * Poller descriptors. + * - <name> is initialized by the poller's register() function, and should not + * be allocated, just linked to. + * - <pref> is initialized by the poller's register() function. It is set to 0 + * by default, meaning the poller is disabled. init() should set it to 0 in + * case of failure. term() must set it to 0. A generic unoptimized select() + * poller should set it to 100. + * - <private> is initialized by the poller's init() function, and cleaned by + * the term() function. + * - clo() should be used to do indicate the poller that fd will be closed. + * - poll() calls the poller, expiring at <exp>, or immediately if <wake> is set + * - flags indicate what the poller supports (HAP_POLL_F_*) + */ + +#define HAP_POLL_F_RDHUP 0x00000001 /* the poller notifies of HUP with reads */ +#define HAP_POLL_F_ERRHUP 0x00000002 /* the poller reports ERR and HUP */ + +struct poller { + void *private; /* any private data for the poller */ + void (*clo)(const int fd); /* mark <fd> as closed */ + void (*poll)(struct poller *p, int exp, int wake); /* the poller itself */ + int (*init)(struct poller *p); /* poller initialization */ + void (*term)(struct poller *p); /* termination of this poller */ + int (*test)(struct poller *p); /* pre-init check of the poller */ + int (*fork)(struct poller *p); /* post-fork re-opening */ + const char *name; /* poller name */ + unsigned int flags; /* HAP_POLL_F_* */ + int pref; /* try pollers with higher preference first */ +}; + +#endif /* _HAPROXY_FD_T_H */ + +/* + * Local variables: + * c-indent-level: 8 + * c-basic-offset: 8 + * End: + */ |