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diff --git a/lib/lufa/Projects/Webserver/Lib/DHCPServerApp.c b/lib/lufa/Projects/Webserver/Lib/DHCPServerApp.c
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1/*
2 LUFA Library
3 Copyright (C) Dean Camera, 2017.
4
5 dean [at] fourwalledcubicle [dot] com
6 www.lufa-lib.org
7*/
8
9/*
10 Copyright 2017 Dean Camera (dean [at] fourwalledcubicle [dot] com)
11
12 Permission to use, copy, modify, distribute, and sell this
13 software and its documentation for any purpose is hereby granted
14 without fee, provided that the above copyright notice appear in
15 all copies and that both that the copyright notice and this
16 permission notice and warranty disclaimer appear in supporting
17 documentation, and that the name of the author not be used in
18 advertising or publicity pertaining to distribution of the
19 software without specific, written prior permission.
20
21 The author disclaims all warranties with regard to this
22 software, including all implied warranties of merchantability
23 and fitness. In no event shall the author be liable for any
24 special, indirect or consequential damages or any damages
25 whatsoever resulting from loss of use, data or profits, whether
26 in an action of contract, negligence or other tortious action,
27 arising out of or in connection with the use or performance of
28 this software.
29*/
30
31/** \file
32 *
33 * DHCP Server Application. When connected to the uIP stack, this will send IP configuration settings to a
34 * DHCP client on the network.
35 */
36
37#define INCLUDE_FROM_DHCPSERVERAPP_C
38#include "DHCPServerApp.h"
39
40#if defined(ENABLE_DHCP_SERVER) || defined(__DOXYGEN__)
41
42struct uip_conn* BroadcastConnection;
43
44uint8_t LeasedIPs[255 / 8];
45
46/** Initialization function for the DHCP server. */
47void DHCPServerApp_Init(void)
48{
49 /* Listen on port 67 for DHCP server connections from hosts */
50 uip_listen(HTONS(DHCP_SERVER_PORT));
51
52 /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
53 struct uip_udp_conn* BroadcastConnection = uip_udp_new(&uip_broadcast_addr, HTONS(DHCP_CLIENT_PORT));
54
55 /* If the connection was successfully created, bind it to the local DHCP client port */
56 if (BroadcastConnection != NULL)
57 uip_udp_bind(BroadcastConnection, HTONS(DHCP_SERVER_PORT));
58
59 /* Set all IP addresses as unleased */
60 memset(LeasedIPs, 0x00, sizeof(LeasedIPs));
61}
62
63/** uIP stack application callback for the DHCP server. This function must be called each time the TCP/IP stack
64 * needs a UDP packet to be processed.
65 */
66void DHCPServerApp_Callback(void)
67{
68 DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata;
69 uint16_t AppDataSize = 0;
70
71 /* Only process when new data arrives - don't retransmit lost packets */
72 if (uip_newdata())
73 {
74 /* Get the DHCP message type (if present), otherwise early-abort */
75 uint8_t DHCPMessageType;
76 if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
77 return;
78
79 uip_ipaddr_t Netmask, GatewayIPAddress, PreferredClientIP;
80 struct uip_eth_addr RemoteMACAddress;
81 uint32_t TransactionID;
82
83 /* Get configured network mask, gateway IP and extract out DHCP transaction ID and remote IP */
84 uip_getnetmask(&Netmask);
85 uip_getdraddr(&GatewayIPAddress);
86 memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
87 TransactionID = AppData->TransactionID;
88
89 /* Try to extract out the client's preferred IP address if it is indicated in the packet */
90 if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, &PreferredClientIP)))
91 memcpy(&PreferredClientIP, &uip_all_zeroes_addr, sizeof(uip_ipaddr_t));
92
93 switch (DHCPMessageType)
94 {
95 case DHCP_DISCOVER:
96 /* If no preference was made or the preferred IP is already taken, find a new address */
97 if (DHCPServerApp_CheckIfIPLeased(&PreferredClientIP))
98 DHCPServerApp_GetUnleasedIP(&PreferredClientIP);
99
100 /* Create a new DHCP OFFER packet with the offered IP address */
101 AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, &PreferredClientIP, TransactionID);
102
103 /* Add network mask and router information to the list of DHCP OFFER packet options */
104 AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
105 sizeof(uip_ipaddr_t), &Netmask);
106 AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
107 sizeof(uip_ipaddr_t), &GatewayIPAddress);
108
109 /* Send the DHCP OFFER packet */
110 uip_poll_conn(BroadcastConnection);
111 memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
112 uip_udp_send(AppDataSize);
113
114 break;
115 case DHCP_REQUEST:
116 /* Check to see if the requested IP address has already been leased to a client */
117 if (!(DHCPServerApp_CheckIfIPLeased(&PreferredClientIP)))
118 {
119 /* Create a new DHCP ACK packet to accept the IP address lease */
120 AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &RemoteMACAddress, &PreferredClientIP, TransactionID);
121
122 /* Add network mask and router information to the list of DHCP ACK packet options */
123 AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
124 sizeof(uip_ipaddr_t), &Netmask);
125 AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
126 sizeof(uip_ipaddr_t), &GatewayIPAddress);
127
128 /* Mark the requested IP as leased to a client */
129 DHCPServerApp_LeaseIP(&PreferredClientIP);
130 }
131 else
132 {
133 /* Create a new DHCP NAK packet to reject the requested allocation */
134 AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, &uip_all_zeroes_addr, TransactionID);
135 }
136
137 /* Send the DHCP ACK or NAK packet */
138 uip_poll_conn(BroadcastConnection);
139 memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
140 uip_udp_send(AppDataSize);
141
142 break;
143 case DHCP_RELEASE:
144 /* Mark the IP address as released in the allocation table */
145 DHCPServerApp_UnleaseIP(&uip_udp_conn->ripaddr);
146 break;
147 }
148 }
149}
150
151/** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
152 * fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP client.
153 *
154 * \param[out] DHCPHeader Location in the packet buffer where the BOOTP header should be written to
155 * \param[in] DHCPMessageType DHCP Message type, such as DHCP_DISCOVER
156 * \param[in] ClientHardwareAddress Client MAC address the created transaction should be directed to
157 * \param[in] PreferredClientIP Preferred IP that should be given to the client if it is unallocated
158 * \param[in] TransactionID Transaction ID the created transaction should be associated with
159 *
160 * \return Size in bytes of the created DHCP packet
161 */
162static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
163 const uint8_t DHCPMessageType,
164 const struct uip_eth_addr* const ClientHardwareAddress,
165 const uip_ipaddr_t* const PreferredClientIP,
166 const uint32_t TransactionID)
167{
168 /* Erase existing packet data so that we start will all 0x00 DHCP header data */
169 memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
170
171 DHCPHeader->Operation = DHCPMessageType;
172 DHCPHeader->HardwareType = DHCP_HTYPE_ETHERNET;
173 DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
174 DHCPHeader->Hops = 0;
175 DHCPHeader->TransactionID = TransactionID;
176 DHCPHeader->ElapsedSeconds = 0;
177 DHCPHeader->Flags = 0;
178 memcpy(&DHCPHeader->NextServerIP, &uip_hostaddr, sizeof(uip_ipaddr_t));
179 memcpy(&DHCPHeader->YourIP, PreferredClientIP, sizeof(uip_ipaddr_t));
180 memcpy(&DHCPHeader->ClientHardwareAddress, ClientHardwareAddress, sizeof(struct uip_eth_addr));
181 DHCPHeader->Cookie = DHCP_MAGIC_COOKIE;
182
183 /* Add a DHCP message type and terminator options to the start of the DHCP options field */
184 DHCPHeader->Options[0] = DHCP_OPTION_MSG_TYPE;
185 DHCPHeader->Options[1] = 1;
186 DHCPHeader->Options[2] = DHCPMessageType;
187 DHCPHeader->Options[3] = DHCP_OPTION_END;
188
189 /* Calculate the total number of bytes added to the outgoing packet */
190 return (sizeof(DHCP_Header_t) + 4);
191}
192
193/** Checks to see if the nominated IP address has already been allocated to a client.
194 *
195 * \param[in] IPAddress IP Address whose lease status should be checked
196 *
197 * \pre The IP address must be within the same /24 subnet as the virtual webserver.
198 *
199 * \return Boolean \c true if the IP has already been leased to a client, \c false otherwise.
200 */
201static bool DHCPServerApp_CheckIfIPLeased(const uip_ipaddr_t* const IPAddress)
202{
203 uint8_t Byte = (IPAddress->u8[3] / 8);
204 uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
205
206 /* Make sure that the requested IP address isn't already leased to the virtual server or another client */
207 if (IPAddress->u8[3] && !(IPAddress->u8[3] == uip_hostaddr.u8[3]) && !(LeasedIPs[Byte] & Mask))
208 return false;
209 else
210 return true;
211}
212
213/** Retrieves the next unleased IP in the IP address pool.
214 *
215 * \param[out] NewIPAddress Location where the generated IP Address should be stored
216 */
217static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* const NewIPAddress)
218{
219 uip_ipaddr_copy(NewIPAddress, &uip_hostaddr);
220
221 /** Look through the current subnet, skipping the broadcast and zero IP addresses */
222 for (uint8_t IP = 1; IP < 254; IP++)
223 {
224 /* Update new IP address to lease with the current IP address to test */
225 NewIPAddress->u8[3] = IP;
226
227 /* If we've found an unleased IP, abort with the updated IP stored for the called */
228 if (!(DHCPServerApp_CheckIfIPLeased(NewIPAddress)))
229 return;
230 }
231}
232
233/** Marks the given IP Address as leased in the address pool, so that it will not be
234 * allocated to another client unless it is first released.
235 *
236 * \param[in] IPAddress IP Address to mark as leased
237 *
238 * \pre The IP address must be within the same /24 subnet as the virtual webserver.
239 */
240static void DHCPServerApp_LeaseIP(const uip_ipaddr_t* const IPAddress)
241{
242 uint8_t Byte = (IPAddress->u8[3] / 8);
243 uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
244
245 /* Mark the IP address as leased in the allocation table */
246 LeasedIPs[Byte] |= Mask;
247}
248
249/** Marks the given IP Address as not leased in the address pool, so that it can be
250 * allocated to another client upon request.
251 *
252 * \param[in] IPAddress IP Address to mark as not leased
253 *
254 * \pre The IP address must be within the same /24 subnet as the virtual webserver.
255 */
256static void DHCPServerApp_UnleaseIP(const uip_ipaddr_t* const IPAddress)
257{
258 uint8_t Byte = (IPAddress->u8[3] / 8);
259 uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
260
261 /* Mark the IP address as unleased in the allocation table */
262 LeasedIPs[Byte] &= ~Mask;
263}
264#endif
265
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-17 21:35:56 +0000