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