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Diffstat (limited to 'freebsd/sys/sys/hhook.h')
| -rw-r--r-- | freebsd/sys/sys/hhook.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/freebsd/sys/sys/hhook.h b/freebsd/sys/sys/hhook.h new file mode 100644 index 00000000..51eda1fd --- /dev/null +++ b/freebsd/sys/sys/hhook.h @@ -0,0 +1,156 @@ +/*- + * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org> + * Copyright (c) 2010 The FreeBSD Foundation + * All rights reserved. + * + * This software was developed by Lawrence Stewart while studying at the Centre + * for Advanced Internet Architectures, Swinburne University of Technology, made + * possible in part by grants from the FreeBSD Foundation and Cisco University + * Research Program Fund at Community Foundation Silicon Valley. + * + * Portions of this software were developed at the Centre for Advanced + * Internet Architectures, Swinburne University of Technology, Melbourne, + * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ + +/* + * A KPI modelled on the pfil framework for instantiating helper hook points + * within the kernel for use by Khelp modules. Originally released as part of + * the NewTCP research project at Swinburne University of Technology's Centre + * for Advanced Internet Architectures, Melbourne, Australia, which was made + * possible in part by a grant from the Cisco University Research Program Fund + * at Community Foundation Silicon Valley. More details are available at: + * http://caia.swin.edu.au/urp/newtcp/ + */ + +#ifndef _SYS_HHOOK_H_ +#define _SYS_HHOOK_H_ + +/* XXXLAS: Is there a way around this? */ +#include <rtems/bsd/sys/lock.h> +#include <sys/rmlock.h> + +/* hhook_head flags. */ +#define HHH_ISINVNET 0x00000001 /* Is the hook point in a vnet? */ + +/* Flags common to all register functions. */ +#define HHOOK_WAITOK 0x00000001 /* Sleeping allowed. */ +#define HHOOK_NOWAIT 0x00000002 /* Sleeping disallowed. */ +/* Flags only relevant to hhook_head_register() and hhook_head_is_virtual(). */ +#define HHOOK_HEADISINVNET 0x00000100 /* Public proxy for HHH_ISINVNET. */ + +/* Helper hook types. */ +#define HHOOK_TYPE_TCP 1 + +struct helper; +struct osd; + +/* Signature for helper hook functions. */ +typedef int (*hhook_func_t)(int32_t hhook_type, int32_t hhook_id, void *udata, + void *ctx_data, void *hdata, struct osd *hosd); + +/* + * Information required to add/remove a helper hook function to/from a helper + * hook point. + */ +struct hookinfo { + hhook_func_t hook_func; + struct helper *hook_helper; + void *hook_udata; + int32_t hook_id; + int32_t hook_type; +}; + +/* + * Ideally this would be private but we need access to the hhh_nhooks member + * variable in order to make the HHOOKS_RUN_IF() macro low impact. + */ +struct hhook_head { + STAILQ_HEAD(hhook_list, hhook) hhh_hooks; + struct rmlock hhh_lock; + int32_t hhh_id; + int32_t hhh_nhooks; + int32_t hhh_type; + uint32_t hhh_flags; + volatile uint32_t hhh_refcount; + LIST_ENTRY(hhook_head) hhh_next; +}; + +/* Public KPI functions. */ +void hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd); + +int hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, + uint32_t flags); + +int hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags); + +int hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki); + +int hhook_remove_hook_lookup(struct hookinfo *hki); + +int hhook_head_register(int32_t hhook_type, int32_t hhook_id, + struct hhook_head **hhh, uint32_t flags); + +int hhook_head_deregister(struct hhook_head *hhh); + +int hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id); + +struct hhook_head * hhook_head_get(int32_t hhook_type, int32_t hhook_id); + +void hhook_head_release(struct hhook_head *hhh); + +uint32_t hhook_head_is_virtualised(struct hhook_head *hhh); + +uint32_t hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id); + +/* + * A wrapper around hhook_run_hooks() that only calls the function if at least + * one helper hook function is registered for the specified helper hook point. + */ +#define HHOOKS_RUN_IF(hhh, ctx_data, hosd) do { \ + if (hhh != NULL && hhh->hhh_nhooks > 0) \ + hhook_run_hooks(hhh, ctx_data, hosd); \ +} while (0) + +/* + * WARNING: This macro should only be used in code paths that execute + * infrequently, otherwise the refcounting overhead would be excessive. + * + * A similar wrapper to HHOOKS_RUN_IF() for situations where the caller prefers + * not to lookup and store the appropriate hhook_head pointer themselves. + */ +#define HHOOKS_RUN_LOOKUP_IF(hhook_type, hhook_id, ctx_data, hosd) do { \ + struct hhook_head *_hhh; \ + \ + _hhh = hhook_head_get(hhook_type, hhook_id); \ + if (_hhh != NULL) { \ + if (_hhh->hhh_nhooks > 0) \ + hhook_run_hooks(_hhh, ctx_data, hosd); \ + hhook_head_release(_hhh); \ + } \ +} while (0) + +#endif /* _SYS_HHOOK_H_ */ |