3 * $Id: pkbuf.h,v 1.3 2001/02/03 16:23:33 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 1.3 2001/02/03 16:23:33 mdw
34 * Bug fix: handle a disable during a close-induced flush without dumping
37 * Revision 1.2 2001/01/20 12:06:01 mdw
38 * Define flags with macros, to ensure unsignedness.
40 * Revision 1.1 2000/06/17 10:39:19 mdw
41 * Experimental new support for packet buffering.
52 /*----- Header files ------------------------------------------------------*/
64 /*----- Data structures ---------------------------------------------------*/
66 typedef struct pkbuf {
67 size_t sz; /* Size of current buffer */
68 size_t len; /* Length of data in the buffer */
69 size_t want; /* Want this many bytes for packet */
70 unsigned f; /* Various state flags */
71 void (*func)(octet */*b*/, size_t /*sz*/,
72 struct pkbuf */*pk*/, size_t */*keep*/,
73 void */*p*/); /* Handler function */
74 void *p; /* Argument for handler */
75 arena *a; /* Memory allocation arena */
76 octet *buf; /* Actual buffer space */
79 #define PKBUF_ENABLE 1u /* Buffer is currently enabled */
80 #define PKBUF_CLOSE 2u /* Buffer is now closed */
82 /*----- Functions provided ------------------------------------------------*/
84 /* --- @pkbuf_flush@ --- *
86 * Arguments: @pkbuf *pk@ = pointer to buffer block
87 * @octet *p@ = pointer to where to start searching
88 * @size_t len@ = length of new material added
92 * Use: Flushes any complete packets in a packet buffer. New
93 * material is assumed to have been added starting at @p@. If
94 * @p@ is null, then the scan starts at the beginning of the
95 * buffer, and the size of data already in the buffer is used in
98 * It is assumed that the buffer is initially enabled. You
99 * shouldn't be contributing data to a disabled buffer anyway.
100 * However, the buffer handler may at some point disable itself,
101 * and @pkbuf_flush@ can cope with this eventuality. Any
102 * pending data is left at the start of the buffer and can be
103 * flushed out by calling @pkbuf_flush(b, 0, 0)@ if the buffer
104 * is ever re-enabled.
107 extern void pkbuf_flush(pkbuf */*pk*/, octet */*p*/, size_t /*len*/);
109 /* --- @pkbuf_close@ --- *
111 * Arguments: @pkbuf *pk@ = pointer to buffer block
115 * Use: Informs the client that no more data is likely to arrive. If
116 * there is a partial packet in the buffer, it is discarded.
119 extern void pkbuf_close(pkbuf */*pk*/);
121 /* --- @pkbuf_free@ --- *
123 * Arguments: @pkbuf *pk@ = pointer to buffer block
124 * @octet **p@ = output pointer to free space
126 * Returns: Free buffer size.
128 * Use: Returns the free portion of a packet buffer. Data can then
129 * be written to this portion, and split out into packets by
130 * calling @pkbuf_flush@.
133 extern size_t pkbuf_free(pkbuf */*pk*/, octet **/*p*/);
135 /* --- @pkbuf_snarf@ --- *
137 * Arguments: @pkbuf *pk@ = pointer to buffer block
138 * @const void *p@ = pointer to input data buffer
139 * @size_t sz@ = size of data in input buffer
143 * Use: Snarfs the data from the input buffer and spits it out as
144 * packets. This interface ignores the complexities of dealing
145 * with disablement: you should be using @pkbuf_free@ to
146 * contribute data if you want to cope with that.
149 extern void pkbuf_snarf(pkbuf */*pk*/, const void */*p*/, size_t /*sz*/);
151 /* --- @pkbuf_want@ --- *
153 * Arguments: @pkbuf *pk@ = pointer to buffer block
154 * @size_t want@ = how many octets wanted for next packet
158 * Use: Sets the desired size for the next packet to be read. If
159 * it's larger than the current buffer, the buffer is extended.
162 extern void pkbuf_want(pkbuf */*pk*/, size_t /*want*/);
164 /* --- @pkbuf_init@ --- *
166 * Arguments: @pkbuf *pk@ = pointer to buffer block
167 * @void (*func)(octet *b, size_t sz, pkbuf *pk,@
168 * @size_t *keep, void *p)@ =
170 * @void *p@ = argument pointer for @func@
174 * Use: Initializes a packet buffer block. Any packets are passed to
175 * the provided function for handling.
178 extern void pkbuf_init(pkbuf */*pk*/,
179 void (*/*func*/)(octet */*b*/, size_t /*sz*/,
180 pkbuf */*pk*/, size_t */*keep*/,
184 /* --- @pkbuf_destroy@ --- *
186 * Arguments: @pkbuf *pk@ = pointer to buffer block
190 * Use: Deallocates a packet buffer and frees any resources it owned.
193 extern void pkbuf_destroy(pkbuf */*pk*/);
195 /*----- That's all, folks -------------------------------------------------*/