1/*
2 * Copyright (c) 2015-2017, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * * Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Intel Corporation nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** \file
30 * \brief Hamster Wheel Literal Matcher: runtime API.
31 */
32
33#ifndef HWLM_H
34#define HWLM_H
35
36#include "ue2common.h"
37
38#ifdef __cplusplus
39extern "C"
40{
41#endif
42
43/** \brief Error return type for exec functions. */
44typedef int hwlm_error_t;
45
46/** \brief Type representing a set of groups as a bitmap. */
47typedef u64a hwlm_group_t;
48
49/** \brief HWLM callback return type. */
50typedef hwlm_group_t hwlmcb_rv_t;
51
52/** \brief Value representing all possible literal groups. */
53#define HWLM_ALL_GROUPS ((hwlm_group_t)~0ULL)
54
55/** \brief Callback return value indicating that we should continue matching. */
56#define HWLM_CONTINUE_MATCHING HWLM_ALL_GROUPS
57
58/** \brief Callback return value indicating that we should halt matching. */
59#define HWLM_TERMINATE_MATCHING 0
60
61/** \brief Matching finished without being terminated by the user. */
62#define HWLM_SUCCESS 0
63
64/** \brief The user terminated matching by returning HWLM_TERMINATE_MATCHING
65 * from the match callback. */
66#define HWLM_TERMINATED 1
67
68/** \brief An error occurred during matching.
69 *
70 * This should only be used if an unsupported engine was called (like one
71 * designed for a different architecture). */
72#define HWLM_ERROR_UNKNOWN 2
73
74/** \brief Max length of the literal passed to HWLM. */
75#define HWLM_LITERAL_MAX_LEN 8
76
77struct hs_scratch;
78struct HWLM;
79
80/** \brief The type for an HWLM callback.
81 *
82 * This callback receives an end-of-match offset, the ID of the match and
83 * the context pointer that was passed into \ref hwlmExec or
84 * \ref hwlmExecStreaming.
85 *
86 * A callback return of \ref HWLM_TERMINATE_MATCHING will stop matching.
87 *
88 * A callback return of \ref HWLM_CONTINUE_MATCHING continues matching.
89 *
90 * An arbitrary group mask may be given as the return value. This will be taken
91 * as a hint by the underlying engine that only literals with groups
92 * overlapping the provided mask need to be reported.
93 *
94 * The underlying engine may choose not to report a match if there is no group
95 * belonging to the literal which was active at the when the end match location
96 * was first reached.
97 */
98typedef hwlmcb_rv_t (*HWLMCallback)(size_t end, u32 id,
99 struct hs_scratch *scratch);
100
101/** \brief Match strings in table.
102 *
103 * If a match occurs, the callback function given will be called with the index
104 * of the last character in the string and the \p context (passed through
105 * without interpretation).
106 *
107 * Returns \ref HWLM_TERMINATED if scanning is cancelled due to the callback
108 * returning \ref HWLM_TERMINATE_MATCHING.
109 *
110 * \p start is the first offset at which a match may start. Note: match
111 * starts may include masks overhanging the main literal.
112 *
113 * The underlying engine may choose not to report any match which starts before
114 * the first possible match of a literal which is in the initial group mask.
115 */
116hwlm_error_t hwlmExec(const struct HWLM *tab, const u8 *buf, size_t len,
117 size_t start, HWLMCallback callback,
118 struct hs_scratch *scratch, hwlm_group_t groups);
119
120/** \brief As for \ref hwlmExec, but a streaming case across two buffers.
121 *
122 * \p len is the length of the main buffer to be scanned.
123 *
124 * \p start is an advisory hint representing the first offset at which a match
125 * may start. Some underlying literal matches may not respect it. Note: match
126 * starts may include masks overhanging the main literal.
127 *
128 * \p scratch is used to access the history buffer, history length and
129 * the main buffer.
130 *
131 * Two buffers/lengths are provided. Matches that occur entirely within
132 * the history buffer will not be reported by this function. The offsets
133 * reported for the main buffer are relative to the start of that buffer (a
134 * match at byte 10 of the main buffer is reported as 10). Matches that start
135 * in the history buffer will have starts reported with 'negative' values.
136 */
137hwlm_error_t hwlmExecStreaming(const struct HWLM *tab, size_t len, size_t start,
138 HWLMCallback callback,
139 struct hs_scratch *scratch, hwlm_group_t groups);
140
141#ifdef __cplusplus
142} /* extern "C" */
143#endif
144
145#endif
146