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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: pkbuf.h,v 1.4 2002/01/13 13:33:51 mdw Exp $ |
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4 | * |
5 | * Simple packet buffering |
6 | * |
7 | * (c) 2000 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the mLib utilities library. |
13 | * |
14 | * mLib is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * mLib is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with mLib; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: pkbuf.h,v $ |
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33 | * Revision 1.4 2002/01/13 13:33:51 mdw |
34 | * Packet handler functions now have a @typedef@ name. |
35 | * |
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36 | * Revision 1.3 2001/02/03 16:23:33 mdw |
37 | * Bug fix: handle a disable during a close-induced flush without dumping |
38 | * core. |
39 | * |
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40 | * Revision 1.2 2001/01/20 12:06:01 mdw |
41 | * Define flags with macros, to ensure unsignedness. |
42 | * |
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43 | * Revision 1.1 2000/06/17 10:39:19 mdw |
44 | * Experimental new support for packet buffering. |
45 | * |
46 | */ |
47 | |
48 | #ifndef MLIB_PKBUF_H |
49 | #define MLIB_PKBUF_H |
50 | |
51 | #ifdef __cplusplus |
52 | extern "C" { |
53 | #endif |
54 | |
55 | /*----- Header files ------------------------------------------------------*/ |
56 | |
57 | #include <stddef.h> |
58 | |
59 | #ifndef MLIB_ARENA_H |
60 | # include "arena.h" |
61 | #endif |
62 | |
63 | #ifndef MLIB_BITS_H |
64 | # include "bits.h" |
65 | #endif |
66 | |
67 | /*----- Data structures ---------------------------------------------------*/ |
68 | |
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69 | struct pkbuf; |
70 | |
71 | typedef void pkbuf_func(octet */*b*/, size_t /*sz*/, |
72 | struct pkbuf */*pk*/, size_t */*keep*/, |
73 | void */*p*/); |
74 | |
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75 | typedef struct pkbuf { |
76 | size_t sz; /* Size of current buffer */ |
77 | size_t len; /* Length of data in the buffer */ |
78 | size_t want; /* Want this many bytes for packet */ |
79 | unsigned f; /* Various state flags */ |
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80 | pkbuf_func *func; /* Handler function */ |
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81 | void *p; /* Argument for handler */ |
82 | arena *a; /* Memory allocation arena */ |
83 | octet *buf; /* Actual buffer space */ |
84 | } pkbuf; |
85 | |
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86 | #define PKBUF_ENABLE 1u /* Buffer is currently enabled */ |
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87 | #define PKBUF_CLOSE 2u /* Buffer is now closed */ |
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88 | |
89 | /*----- Functions provided ------------------------------------------------*/ |
90 | |
91 | /* --- @pkbuf_flush@ --- * |
92 | * |
93 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
94 | * @octet *p@ = pointer to where to start searching |
95 | * @size_t len@ = length of new material added |
96 | * |
97 | * Returns: --- |
98 | * |
99 | * Use: Flushes any complete packets in a packet buffer. New |
100 | * material is assumed to have been added starting at @p@. If |
101 | * @p@ is null, then the scan starts at the beginning of the |
102 | * buffer, and the size of data already in the buffer is used in |
103 | * place of @len@. |
104 | * |
105 | * It is assumed that the buffer is initially enabled. You |
106 | * shouldn't be contributing data to a disabled buffer anyway. |
107 | * However, the buffer handler may at some point disable itself, |
108 | * and @pkbuf_flush@ can cope with this eventuality. Any |
109 | * pending data is left at the start of the buffer and can be |
110 | * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer |
111 | * is ever re-enabled. |
112 | */ |
113 | |
114 | extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/); |
115 | |
116 | /* --- @pkbuf_close@ --- * |
117 | * |
118 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
119 | * |
120 | * Returns: --- |
121 | * |
122 | * Use: Informs the client that no more data is likely to arrive. If |
123 | * there is a partial packet in the buffer, it is discarded. |
124 | */ |
125 | |
126 | extern void pkbuf_close(pkbuf */*pk*/); |
127 | |
128 | /* --- @pkbuf_free@ --- * |
129 | * |
130 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
131 | * @octet **p@ = output pointer to free space |
132 | * |
133 | * Returns: Free buffer size. |
134 | * |
135 | * Use: Returns the free portion of a packet buffer. Data can then |
136 | * be written to this portion, and split out into packets by |
137 | * calling @pkbuf_flush@. |
138 | */ |
139 | |
140 | extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/); |
141 | |
142 | /* --- @pkbuf_snarf@ --- * |
143 | * |
144 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
145 | * @const void *p@ = pointer to input data buffer |
146 | * @size_t sz@ = size of data in input buffer |
147 | * |
148 | * Returns: --- |
149 | * |
150 | * Use: Snarfs the data from the input buffer and spits it out as |
151 | * packets. This interface ignores the complexities of dealing |
152 | * with disablement: you should be using @pkbuf_free@ to |
153 | * contribute data if you want to cope with that. |
154 | */ |
155 | |
156 | extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/); |
157 | |
158 | /* --- @pkbuf_want@ --- * |
159 | * |
160 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
161 | * @size_t want@ = how many octets wanted for next packet |
162 | * |
163 | * Returns: --- |
164 | * |
165 | * Use: Sets the desired size for the next packet to be read. If |
166 | * it's larger than the current buffer, the buffer is extended. |
167 | */ |
168 | |
169 | extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/); |
170 | |
171 | /* --- @pkbuf_init@ --- * |
172 | * |
173 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
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174 | * @pkbuf_func *func@ = handler function |
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175 | * @void *p@ = argument pointer for @func@ |
176 | * |
177 | * Returns: --- |
178 | * |
179 | * Use: Initializes a packet buffer block. Any packets are passed to |
180 | * the provided function for handling. |
181 | */ |
182 | |
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183 | extern void pkbuf_init(pkbuf */*pk*/, pkbuf_func */*func*/, void */*p*/); |
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184 | |
185 | /* --- @pkbuf_destroy@ --- * |
186 | * |
187 | * Arguments: @pkbuf *pk@ = pointer to buffer block |
188 | * |
189 | * Returns: --- |
190 | * |
191 | * Use: Deallocates a packet buffer and frees any resources it owned. |
192 | */ |
193 | |
194 | extern void pkbuf_destroy(pkbuf */*pk*/); |
195 | |
196 | /*----- That's all, folks -------------------------------------------------*/ |
197 | |
198 | #ifdef __cplusplus |
199 | } |
200 | #endif |
201 | |
202 | #endif |