diff options
Diffstat (limited to 'lib/lufa/Demos/Device/ClassDriver/RNDISEthernet/Lib/DHCP.c')
| -rw-r--r-- | lib/lufa/Demos/Device/ClassDriver/RNDISEthernet/Lib/DHCP.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/lib/lufa/Demos/Device/ClassDriver/RNDISEthernet/Lib/DHCP.c b/lib/lufa/Demos/Device/ClassDriver/RNDISEthernet/Lib/DHCP.c new file mode 100644 index 0000000000..7adc648360 --- /dev/null +++ b/lib/lufa/Demos/Device/ClassDriver/RNDISEthernet/Lib/DHCP.c @@ -0,0 +1,129 @@ +/* + 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 + * + * Dynamic Host Configuration Protocol (DHCP) packet handling routines. This protocol + * handles the automatic IP negotiation to the host, so that the host will use the provided + * IP address given to it by the device. + */ + +#include "DHCP.h" + +/** Processes a DHCP packet inside an Ethernet frame, and writes the appropriate response + * to the output Ethernet frame if the host is requesting or accepting an IP address. + * + * \param[in] IPHeaderInStart Pointer to the start of the incoming packet's IP header + * \param[in] DHCPHeaderInStart Pointer to the start of the incoming packet's DHCP header + * \param[out] DHCPHeaderOutStart Pointer to the start of the outgoing packet's DHCP header + * + * \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE otherwise + */ +int16_t DHCP_ProcessDHCPPacket(void* IPHeaderInStart, + void* DHCPHeaderInStart, + void* DHCPHeaderOutStart) +{ + IP_Header_t* IPHeaderIN = (IP_Header_t*)IPHeaderInStart; + DHCP_Header_t* DHCPHeaderIN = (DHCP_Header_t*)DHCPHeaderInStart; + DHCP_Header_t* DHCPHeaderOUT = (DHCP_Header_t*)DHCPHeaderOutStart; + + uint8_t* DHCPOptionsINStart = ((uint8_t*)DHCPHeaderInStart + sizeof(DHCP_Header_t)); + uint8_t* DHCPOptionsOUTStart = ((uint8_t*)DHCPHeaderOutStart + sizeof(DHCP_Header_t)); + + DecodeDHCPHeader(DHCPHeaderInStart); + + /* Zero out the response DHCP packet, as much of it is legacy and left at 0 */ + memset(DHCPHeaderOUT, 0, sizeof(DHCP_Header_t)); + + /* Fill out the response DHCP packet */ + DHCPHeaderOUT->HardwareType = DHCPHeaderIN->HardwareType; + DHCPHeaderOUT->Operation = DHCP_OP_BOOTREPLY; + DHCPHeaderOUT->HardwareAddressLength = DHCPHeaderIN->HardwareAddressLength; + DHCPHeaderOUT->Hops = 0; + DHCPHeaderOUT->TransactionID = DHCPHeaderIN->TransactionID; + DHCPHeaderOUT->ElapsedSeconds = 0; + DHCPHeaderOUT->Flags = DHCPHeaderIN->Flags; + DHCPHeaderOUT->YourIP = ClientIPAddress; + memmove(&DHCPHeaderOUT->ClientHardwareAddress, &DHCPHeaderIN->ClientHardwareAddress, sizeof(MAC_Address_t)); + DHCPHeaderOUT->Cookie = SwapEndian_32(DHCP_MAGIC_COOKIE); + + /* Alter the incoming IP packet header so that the corrected IP source and destinations are used - this means that + when the response IP header is generated, it will use the corrected addresses and not the null/broatcast addresses */ + IPHeaderIN->SourceAddress = ClientIPAddress; + IPHeaderIN->DestinationAddress = ServerIPAddress; + + /* Process the incoming DHCP packet options */ + while (DHCPOptionsINStart[0] != DHCP_OPTION_END) + { + /* Find the Message Type DHCP option, to determine the type of DHCP packet */ + if (DHCPOptionsINStart[0] == DHCP_OPTION_MESSAGETYPE) + { + if ((DHCPOptionsINStart[2] == DHCP_MESSAGETYPE_DISCOVER) || (DHCPOptionsINStart[2] == DHCP_MESSAGETYPE_REQUEST)) + { + /* Fill out the response DHCP packet options for a DHCP OFFER or ACK response */ + + *(DHCPOptionsOUTStart++) = DHCP_OPTION_MESSAGETYPE; + *(DHCPOptionsOUTStart++) = 1; + *(DHCPOptionsOUTStart++) = (DHCPOptionsINStart[2] == DHCP_MESSAGETYPE_DISCOVER) ? DHCP_MESSAGETYPE_OFFER + : DHCP_MESSAGETYPE_ACK; + + *(DHCPOptionsOUTStart++) = DHCP_OPTION_SUBNETMASK; + *(DHCPOptionsOUTStart++) = sizeof(IP_Address_t); + *(DHCPOptionsOUTStart++) = 0xFF; + *(DHCPOptionsOUTStart++) = 0xFF; + *(DHCPOptionsOUTStart++) = 0xFF; + *(DHCPOptionsOUTStart++) = 0x00; + + *(DHCPOptionsOUTStart++) = DHCP_OPTION_LEASETIME; + *(DHCPOptionsOUTStart++) = sizeof(uint32_t); + /* Lease Time 86400s (ONE_DAY) */ + *(DHCPOptionsOUTStart++) = 0x00; + *(DHCPOptionsOUTStart++) = 0x01; + *(DHCPOptionsOUTStart++) = 0x51; + *(DHCPOptionsOUTStart++) = 0x80; + + *(DHCPOptionsOUTStart++) = DHCP_OPTION_DHCPSERVER; + *(DHCPOptionsOUTStart++) = sizeof(IP_Address_t); + memcpy(DHCPOptionsOUTStart, &ServerIPAddress, sizeof(IP_Address_t)); + DHCPOptionsOUTStart += sizeof(IP_Address_t); + + *(DHCPOptionsOUTStart++) = DHCP_OPTION_END; + + return (sizeof(DHCP_Header_t) + 18 + sizeof(IP_Address_t)); + } + } + + /* Go to the next DHCP option - skip one byte if option is a padding byte, else skip the complete option's size */ + DHCPOptionsINStart += ((DHCPOptionsINStart[0] == DHCP_OPTION_PAD) ? 1 : (DHCPOptionsINStart[1] + 2)); + } + + return NO_RESPONSE; +} + |