1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2010,2013 Lawrence Stewart <lstewart@freebsd.org>
5 * Copyright (c) 2010 The FreeBSD Foundation
6 * All rights reserved.
7 *
8 * This software was developed by Lawrence Stewart while studying at the Centre
9 * for Advanced Internet Architectures, Swinburne University of Technology, made
10 * possible in part by grants from the FreeBSD Foundation and Cisco University
11 * Research Program Fund at Community Foundation Silicon Valley.
12 *
13 * Portions of this software were developed at the Centre for Advanced
14 * Internet Architectures, Swinburne University of Technology, Melbourne,
15 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
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#define HHOOK_TYPE_SOCKET 2
68#define HHOOK_TYPE_IPSEC_IN 3
69#define HHOOK_TYPE_IPSEC_OUT 4
70
71struct helper;
72struct osd;
73
74/* Signature for helper hook functions. */
75typedef int (*hhook_func_t)(int32_t hhook_type, int32_t hhook_id, void *udata,
76 void *ctx_data, void *hdata, struct osd *hosd);
77
78/*
79 * Information required to add/remove a helper hook function to/from a helper
80 * hook point.
81 */
82struct hookinfo {
83 hhook_func_t hook_func;
84 struct helper *hook_helper;
85 void *hook_udata;
86 int32_t hook_id;
87 int32_t hook_type;
88};
89
90/*
91 * Ideally this would be private but we need access to the hhh_nhooks member
92 * variable in order to make the HHOOKS_RUN_IF() macro low impact.
93 */
94struct hhook_head {
95 STAILQ_HEAD(hhook_list, hhook) hhh_hooks;
96 struct rmlock hhh_lock;
97 uintptr_t hhh_vid;
98 int32_t hhh_id;
99 int32_t hhh_nhooks;
100 int32_t hhh_type;
101 uint32_t hhh_flags;
102 volatile uint32_t hhh_refcount;
103 LIST_ENTRY(hhook_head) hhh_next;
104 LIST_ENTRY(hhook_head) hhh_vnext;
105};
106
107/* Public KPI functions. */
108void hhook_run_hooks(struct hhook_head *hhh, void *ctx_data, struct osd *hosd);
109
110int hhook_add_hook(struct hhook_head *hhh, const struct hookinfo *hki,
111 uint32_t flags);
112
113int hhook_add_hook_lookup(const struct hookinfo *hki, uint32_t flags);
114
115int hhook_remove_hook(struct hhook_head *hhh, const struct hookinfo *hki);
116
117int hhook_remove_hook_lookup(const struct hookinfo *hki);
118
119int hhook_head_register(int32_t hhook_type, int32_t hhook_id,
120 struct hhook_head **hhh, uint32_t flags);
121
122int hhook_head_deregister(struct hhook_head *hhh);
123
124int hhook_head_deregister_lookup(int32_t hhook_type, int32_t hhook_id);
125
126struct hhook_head * hhook_head_get(int32_t hhook_type, int32_t hhook_id);
127
128void hhook_head_release(struct hhook_head *hhh);
129
130uint32_t hhook_head_is_virtualised(struct hhook_head *hhh);
131
132uint32_t hhook_head_is_virtualised_lookup(int32_t hook_type, int32_t hook_id);
133
134/*
135 * A wrapper around hhook_run_hooks() that only calls the function if at least
136 * one helper hook function is registered for the specified helper hook point.
137 */
138#define HHOOKS_RUN_IF(hhh, ctx_data, hosd) do { \
139 if (hhh != NULL && hhh->hhh_nhooks > 0) \
140 hhook_run_hooks(hhh, ctx_data, hosd); \
141} while (0)
142
143/*
144 * WARNING: This macro should only be used in code paths that execute
145 * infrequently, otherwise the refcounting overhead would be excessive.
146 *
147 * A similar wrapper to HHOOKS_RUN_IF() for situations where the caller prefers
148 * not to lookup and store the appropriate hhook_head pointer themselves.
149 */
150#define HHOOKS_RUN_LOOKUP_IF(hhook_type, hhook_id, ctx_data, hosd) do { \
151 struct hhook_head *_hhh; \
152 \
153 _hhh = hhook_head_get(hhook_type, hhook_id); \
154 if (_hhh != NULL) { \
155 if (_hhh->hhh_nhooks > 0) \
156 hhook_run_hooks(_hhh, ctx_data, hosd); \
157 hhook_head_release(_hhh); \
158 } \
159} while (0)
160
161#endif /* _SYS_HHOOK_H_ */