3 * $Id: pkbuf.h,v 1.2 2001/01/20 12:06:01 mdw Exp $
5 * Simple packet buffering
7 * (c) 2000 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
33 * Revision 1.2 2001/01/20 12:06:01 mdw
34 * Define flags with macros, to ensure unsignedness.
36 * Revision 1.1 2000/06/17 10:39:19 mdw
37 * Experimental new support for packet buffering.
48 /*----- Header files ------------------------------------------------------*/
60 /*----- Data structures ---------------------------------------------------*/
62 typedef struct pkbuf {
63 size_t sz; /* Size of current buffer */
64 size_t len; /* Length of data in the buffer */
65 size_t want; /* Want this many bytes for packet */
66 unsigned f; /* Various state flags */
67 void (*func)(octet */*b*/, size_t /*sz*/,
68 struct pkbuf */*pk*/, size_t */*keep*/,
69 void */*p*/); /* Handler function */
70 void *p; /* Argument for handler */
71 arena *a; /* Memory allocation arena */
72 octet *buf; /* Actual buffer space */
75 #define PKBUF_ENABLE 1u /* Buffer is currently enabled */
77 /*----- Functions provided ------------------------------------------------*/
79 /* --- @pkbuf_flush@ --- *
81 * Arguments: @pkbuf *pk@ = pointer to buffer block
82 * @octet *p@ = pointer to where to start searching
83 * @size_t len@ = length of new material added
87 * Use: Flushes any complete packets in a packet buffer. New
88 * material is assumed to have been added starting at @p@. If
89 * @p@ is null, then the scan starts at the beginning of the
90 * buffer, and the size of data already in the buffer is used in
93 * It is assumed that the buffer is initially enabled. You
94 * shouldn't be contributing data to a disabled buffer anyway.
95 * However, the buffer handler may at some point disable itself,
96 * and @pkbuf_flush@ can cope with this eventuality. Any
97 * pending data is left at the start of the buffer and can be
98 * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer
102 extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/);
104 /* --- @pkbuf_close@ --- *
106 * Arguments: @pkbuf *pk@ = pointer to buffer block
110 * Use: Informs the client that no more data is likely to arrive. If
111 * there is a partial packet in the buffer, it is discarded.
114 extern void pkbuf_close(pkbuf */*pk*/);
116 /* --- @pkbuf_free@ --- *
118 * Arguments: @pkbuf *pk@ = pointer to buffer block
119 * @octet **p@ = output pointer to free space
121 * Returns: Free buffer size.
123 * Use: Returns the free portion of a packet buffer. Data can then
124 * be written to this portion, and split out into packets by
125 * calling @pkbuf_flush@.
128 extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/);
130 /* --- @pkbuf_snarf@ --- *
132 * Arguments: @pkbuf *pk@ = pointer to buffer block
133 * @const void *p@ = pointer to input data buffer
134 * @size_t sz@ = size of data in input buffer
138 * Use: Snarfs the data from the input buffer and spits it out as
139 * packets. This interface ignores the complexities of dealing
140 * with disablement: you should be using @pkbuf_free@ to
141 * contribute data if you want to cope with that.
144 extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/);
146 /* --- @pkbuf_want@ --- *
148 * Arguments: @pkbuf *pk@ = pointer to buffer block
149 * @size_t want@ = how many octets wanted for next packet
153 * Use: Sets the desired size for the next packet to be read. If
154 * it's larger than the current buffer, the buffer is extended.
157 extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/);
159 /* --- @pkbuf_init@ --- *
161 * Arguments: @pkbuf *pk@ = pointer to buffer block
162 * @void (*func)(octet *b, size_t sz, pkbuf *pk,@
163 * @size_t *keep, void *p)@ =
165 * @void *p@ = argument pointer for @func@
169 * Use: Initializes a packet buffer block. Any packets are passed to
170 * the provided function for handling.
173 extern void pkbuf_init(pkbuf */*pk*/,
174 void (*/*func*/)(octet */*b*/, size_t /*sz*/,
175 pkbuf */*pk*/, size_t */*keep*/,
179 /* --- @pkbuf_destroy@ --- *
181 * Arguments: @pkbuf *pk@ = pointer to buffer block
185 * Use: Deallocates a packet buffer and frees any resources it owned.
188 extern void pkbuf_destroy(pkbuf */*pk*/);
190 /*----- That's all, folks -------------------------------------------------*/