DHCPCommon.c
3.85 KB
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
/*
LUFA Library
Copyright (C) Dean Camera, 2017.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
Copyright 2017 Dean Camera (dean [at] fourwalledcubicle [dot] com)
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby granted
without fee, provided that the above copyright notice appear in
all copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of the author not be used in
advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
The author disclaims all warranties with regard to this
software, including all implied warranties of merchantability
and fitness. In no event shall the author be liable for any
special, indirect or consequential damages or any damages
whatsoever resulting from loss of use, data or profits, whether
in an action of contract, negligence or other tortious action,
arising out of or in connection with the use or performance of
this software.
*/
/** \file
*
* Common DHCP routines to manage DHCP packet data.
*/
#include "DHCPCommon.h"
#if defined(ENABLE_DHCP_CLIENT) || defined(ENABLE_DHCP_SERVER) || defined(__DOXYGEN__)
/** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the
* end of options terminator past the new option in the options list.
*
* \param[in,out] DHCPOptionList Pointer to the start of the DHCP packet's options list
* \param[in] Option DHCP option to add to the list
* \param[in] DataLen Size in bytes of the option data to add
* \param[in] OptionData Buffer where the option's data is to be sourced from
*
* \return Number of bytes added to the DHCP packet
*/
uint8_t DHCPCommon_SetOption(uint8_t* DHCPOptionList,
const uint8_t Option,
const uint8_t DataLen,
void* const OptionData)
{
/* Skip through the DHCP options list until the terminator option is found */
while (*DHCPOptionList != DHCP_OPTION_END)
DHCPOptionList += (DHCPOptionList[1] + 2);
/* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
DHCPOptionList[0] = Option;
DHCPOptionList[1] = DataLen;
memcpy(&DHCPOptionList[2], OptionData, DataLen);
DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
/* Calculate the total number of bytes added to the outgoing packet */
return (2 + DataLen);
}
/** Retrieves the given option's data (if present) from the DHCP packet's options list.
*
* \param[in,out] DHCPOptionList Pointer to the start of the DHCP packet's options list
* \param[in] Option DHCP option to retrieve to the list
* \param[out] Destination Buffer where the option's data is to be written to if found
*
* \return Boolean \c true if the option was found in the DHCP packet's options list, \c false otherwise
*/
bool DHCPCommon_GetOption(const uint8_t* DHCPOptionList,
const uint8_t Option,
void* const Destination)
{
/* Look through the incoming DHCP packet's options list for the requested option */
while (*DHCPOptionList != DHCP_OPTION_END)
{
/* Check if the current DHCP option in the packet is the one requested */
if (DHCPOptionList[0] == Option)
{
/* Copy request option's data to the destination buffer */
memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
/* Indicate that the requested option data was successfully retrieved */
return true;
}
/* Skip to next DHCP option in the options list */
DHCPOptionList += (DHCPOptionList[1] + 2);
}
/* Requested option not found in the incoming packet's DHCP options list */
return false;
}
#endif