1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
|
// $Id: Packet.nc,v 1.9 2010-06-29 22:07:46 scipio Exp $
/*
* Copyright (c) 2004-5 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
* - Neither the name of the University of California nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright (c) 2004-5 Intel Corporation
* All rights reserved.
*
* This file is distributed under the terms in the attached INTEL-LICENSE
* file. If you do not find these files, copies can be found by writing to
* Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA,
* 94704. Attention: Intel License Inquiry.
*/
/**
* The basic message data type accessors. Protocols may use
* additional packet interfaces for their protocol specific
* data/metadata.
*
* @author Philip Levis
* @date January 5 2005
* @see TEP 116: Packet Protocols
*/
#include <message.h>
interface Packet {
/**
* Clear out this packet. Note that this is a deep operation and
* total operation: calling clear() on any layer will completely
* clear the packet for reuse.
* @param 'message_t* ONE msg' the packet to clear
*/
command void clear(message_t* msg);
/**
* Return the length of the payload of msg. This value may be less
* than what maxPayloadLength() returns, if the packet is smaller than
* the MTU. If a communication component does not support variably
* sized data regions, then payloadLength() will always return
* the same value as maxPayloadLength().
*
* @param 'message_t* ONE msg' the packet to examine
* @return the length of its current payload
*/
command uint8_t payloadLength(message_t* msg);
/**
* Set the length field of the packet. This value is not checked
* for validity (e.g., if it is larger than the maximum payload
* size). This command is not used when sending packets, as calls
* to send include a length parameter. Rather, it is used by
* components, such as queues, that need to buffer requests to
* send. This command allows the component to store the length
* specified in the request and later recover it when actually
* sending.
*
* @param 'message_t* ONE msg' the packet
* @param len the value to set its length field to
*/
command void setPayloadLength(message_t* msg, uint8_t len);
/**
* Return the maximum payload length that this communication layer
* can provide. Note that, depending on protocol fields, a given
* request to send a packet may not be able to send the maximum
* payload length (e.g., if there are variable length
* fields). Protocols may provide specialized interfaces for these
* circumstances.
*
* @return the maximum size payload allowed by this layer
*/
command uint8_t maxPayloadLength();
/**
* Return a pointer to a protocol's payload region in a packet.
* If the caller intends to write to the payload region then
* the <tt>len</tt> parameter must reflect the maximum required
* length. If the caller (only) wants to read from the payload
* region, then <tt>len</tt> may be set to the value of
* payloadLength(). If the payload region is smaller than
* <tt>len</tt> this command returns NULL. The offset where
* the payload region starts within a packet is fixed, i.e. for
* a given <tt>msg</tt> this command will always return the same
* pointer or NULL.
*
* @param 'message_t* ONE msg' the packet
* @param len the length of payload required
* @return 'void* COUNT_NOK(len)' a pointer to the packet's data payload for this layer
* or NULL if <tt>len</tt> is too big
*/
command void* getPayload(message_t* msg, uint8_t len);
}
|
