1 /*- 2 * Copyright (c) 2010,2013 Lawrence Stewart <lstewart@freebsd.org> 3 * Copyright (c) 2010 The FreeBSD Foundation 4 * All rights reserved. 5 * 6 * This software was developed by Lawrence Stewart while studying at the Centre 7 * for Advanced Internet Architectures, Swinburne University of Technology, made 8 * possible in part by grants from the FreeBSD Foundation and Cisco University 9 * Research Program Fund at Community Foundation Silicon Valley. 10 * 11 * Portions of this software were developed at the Centre for Advanced 12 * Internet Architectures, Swinburne University of Technology, Melbourne, 13 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD$ 37 */ 38 39 /* 40 * A KPI modelled on the pfil framework for instantiating helper hook points 41 * within the kernel for use by Khelp modules. Originally released as part of 42 * the NewTCP research project at Swinburne University of Technology's Centre 43 * for Advanced Internet Architectures, Melbourne, Australia, which was made 44 * possible in part by a grant from the Cisco University Research Program Fund 45 * at Community Foundation Silicon Valley. More details are available at: 46 * http://caia.swin.edu.au/urp/newtcp/ 47 */ 48 49 #ifndef _SYS_HHOOK_H_ 50 #define _SYS_HHOOK_H_ 51 52 /* XXXLAS: Is there a way around this? */ 53 #include <sys/lock.h> 54 #include <sys/rmlock.h> 55 56 /* hhook_head flags. */ 57 #define HHH_ISINVNET 0x00000001 /* Is the hook point in a vnet? */ 58 59 /* Flags common to all register functions. */ 60 #define HHOOK_WAITOK 0x00000001 /* Sleeping allowed. */ 61 #define HHOOK_NOWAIT 0x00000002 /* Sleeping disallowed. */ 62 /* Flags only relevant to hhook_head_register() and hhook_head_is_virtual(). */ 63 #define HHOOK_HEADISINVNET 0x00000100 /* Public proxy for HHH_ISINVNET. */ 64 65 /* Helper hook types. */ 66 #define HHOOK_TYPE_TCP 1 67 68 struct helper; 69 struct osd; 70 71 /* Signature for helper hook functions. */ 72 typedef int (*hhook_func_t)(int32_t hhook_type, int32_t hhook_id, void *udata, 73 void *ctx_data, void *hdata, struct osd *hosd); 74 75 /* 76 * Information required to add/remove a helper hook function to/from a helper 77 * hook point. 78 */ 79 struct hookinfo { 80 hhook_func_t hook_func; 81 struct helper *hook_helper; 82 void *hook_udata; 83 int32_t hook_id; 84 int32_t hook_type; 85 }; 86 87 /* 88 * Ideally this would be private but we need access to the hhh_nhooks member 89 * variable in order to make the HHOOKS_RUN_IF() macro low impact. 90 */ 91 struct hhook_head { 92 STAILQ_HEAD(hhook_list, hhook) hhh_hooks; 93 struct rmlock hhh_lock; 94 uintptr_t hhh_vid; 95 int32_t hhh_id; 96 int32_t hhh_nhooks; 97 int32_t hhh_type; 98 uint32_t hhh_flags; 99 volatile uint32_t hhh_refcount; 100 LIST_ENTRY(hhook_head) hhh_next; 101 LIST_ENTRY(hhook_head) hhh_vnext; 102 }; 103 104 /* Public KPI functions. */ 105 void hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd); 106 107 int hhook_add_hook(struct hhook_head *hhh, struct hookinfo *hki, 108 uint32_t flags); 109 110 int hhook_add_hook_lookup(struct hookinfo *hki, uint32_t flags); 111 112 int hhook_remove_hook(struct hhook_head *hhh, struct hookinfo *hki); 113 114 int hhook_remove_hook_lookup(struct hookinfo *hki); 115 116 int hhook_head_register(int32_t hhook_type, int32_t hhook_id, 117 struct hhook_head **hhh, uint32_t flags); 118 119 int hhook_head_deregister(struct hhook_head *hhh); 120 121 int hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id); 122 123 struct hhook_head * hhook_head_get(int32_t hhook_type, int32_t hhook_id); 124 125 void hhook_head_release(struct hhook_head *hhh); 126 127 uint32_t hhook_head_is_virtualised(struct hhook_head *hhh); 128 129 uint32_t hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id); 130 131 /* 132 * A wrapper around hhook_run_hooks() that only calls the function if at least 133 * one helper hook function is registered for the specified helper hook point. 134 */ 135 #define HHOOKS_RUN_IF(hhh, ctx_data, hosd) do { \ 136 if (hhh != NULL && hhh->hhh_nhooks > 0) \ 137 hhook_run_hooks(hhh, ctx_data, hosd); \ 138 } while (0) 139 140 /* 141 * WARNING: This macro should only be used in code paths that execute 142 * infrequently, otherwise the refcounting overhead would be excessive. 143 * 144 * A similar wrapper to HHOOKS_RUN_IF() for situations where the caller prefers 145 * not to lookup and store the appropriate hhook_head pointer themselves. 146 */ 147 #define HHOOKS_RUN_LOOKUP_IF(hhook_type, hhook_id, ctx_data, hosd) do { \ 148 struct hhook_head *_hhh; \ 149 \ 150 _hhh = hhook_head_get(hhook_type, hhook_id); \ 151 if (_hhh != NULL) { \ 152 if (_hhh->hhh_nhooks > 0) \ 153 hhook_run_hooks(_hhh, ctx_data, hosd); \ 154 hhook_head_release(_hhh); \ 155 } \ 156 } while (0) 157 158 #endif /* _SYS_HHOOK_H_ */ 159