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104 lines
3.2 KiB
104 lines
3.2 KiB
5 months ago
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/*
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* include/haproxy/port_range.h
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* This file defines everything needed to manage port ranges
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*
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* Copyright (C) 2000-2020 Willy Tarreau - w@1wt.eu
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _HAPROXY_PORT_RANGE_H
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#define _HAPROXY_PORT_RANGE_H
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#include <stdlib.h>
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#include <haproxy/api.h>
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#include <haproxy/port_range-t.h>
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#define GET_NEXT_OFF(range, off) ((off) == (range)->size - 1 ? 0 : (off) + 1)
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/* return an available port from range <range>, or zero if none is left */
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static inline int port_range_alloc_port(struct port_range *range)
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{
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int ret;
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int get;
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int put;
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get = _HA_ATOMIC_LOAD(&range->get);
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do {
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/* barrier to make sure get is loaded before put */
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__ha_barrier_atomic_load();
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put = _HA_ATOMIC_LOAD(&range->put_t);
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if (unlikely(put == get))
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return 0;
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ret = range->ports[get];
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} while (!(_HA_ATOMIC_CAS(&range->get, &get, GET_NEXT_OFF(range, get))));
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return ret;
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}
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/* release port <port> into port range <range>. Does nothing if <port> is zero
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* nor if <range> is null. The caller is responsible for marking the port
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* unused by either setting the port to zero or the range to NULL.
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*/
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static inline void port_range_release_port(struct port_range *range, int port)
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{
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int put;
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if (!port || !range)
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return;
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put = range->put_h;
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/* put_h is reserved for producers, so that they can each get a
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* free slot, put_t is what is used by consumers to know if there's
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* elements available or not
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*/
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/* First reserve or slot, we know the ring buffer can't be full,
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* as we will only ever release port we allocated before
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*/
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while (!(_HA_ATOMIC_CAS(&range->put_h, &put, GET_NEXT_OFF(range, put))));
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_HA_ATOMIC_STORE(&range->ports[put], port);
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/* Barrier to make sure the new port is visible before we change put_t */
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__ha_barrier_atomic_store();
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/* Wait until all the threads that got a slot before us are done */
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while ((volatile int)range->put_t != put)
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__ha_compiler_barrier();
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/* Let the world know we're done, and any potential consumer they
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* can use that port.
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*/
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_HA_ATOMIC_STORE(&range->put_t, GET_NEXT_OFF(range, put));
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}
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/* return a new initialized port range of N ports. The ports are not
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* filled in, it's up to the caller to do it.
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*/
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static inline struct port_range *port_range_alloc_range(int n)
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{
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struct port_range *ret;
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ret = calloc(1, sizeof(struct port_range) +
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(n + 1) * sizeof(((struct port_range *)0)->ports[0]));
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ret->size = n + 1;
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/* Start at the first free element */
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ret->put_h = ret->put_t = n;
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return ret;
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}
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#endif /* _HAPROXY_PORT_RANGE_H */
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/*
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* Local variables:
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* c-indent-level: 8
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* c-basic-offset: 8
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* End:
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*/
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