Andrew Boyson / net

A stack which works with or without an Mbed os library. Provides IPv4 or IPv6 with a full 1500 byte buffer.

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eth/arp.cpp@13:9cd54f7db57a, 2017-05-01 (annotated)

Committer:
andrewboyson
Date:
Mon May 01 18:20:55 2017 +0000
Revision:
13:9cd54f7db57a
Parent:
10:f0854784e960
Child:
14:e75a59c1123d
Added ability to read DNS queries with encoded IP addresses

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 10:f0854784e960 1 #include "mbed.h"
andrewboyson 10:f0854784e960 2 #include "log.h"
andrewboyson 10:f0854784e960 3 #include "net.h"
andrewboyson 13:9cd54f7db57a 4 #include "mac.h"
andrewboyson 10:f0854784e960 5 #include "dhcp.h"
andrewboyson 10:f0854784e960 6
andrewboyson 10:f0854784e960 7 #define REQUEST 1
andrewboyson 10:f0854784e960 8 #define REPLY 2
andrewboyson 10:f0854784e960 9
andrewboyson 10:f0854784e960 10 __packed struct header
andrewboyson 10:f0854784e960 11 {
andrewboyson 10:f0854784e960 12 int16_t hardwareType; //16.bit: (ar$hrd) Hardware address space (e.g., Ethernet, Packet Radio Net). Always 1.
andrewboyson 10:f0854784e960 13 int16_t protocolType; //16.bit: (ar$pro) Protocol address space. For Ethernet hardware, this is from the set of type fields ether_typ$<protocol>. As held in eth.h, eg IPv4 = 0x8000.
andrewboyson 10:f0854784e960 14 int8_t hardwareLength; // 8.bit: (ar$hln) byte length of each hardware address. Always 6 bytes.
andrewboyson 10:f0854784e960 15 int8_t protocolLength; // 8.bit: (ar$pln) byte length of each protocol address. Always 4 bytes.
andrewboyson 10:f0854784e960 16 int16_t opCode; //16.bit: (ar$op) opcode (ares_op$REQUEST = 1 | ares_op$REPLY = 2), high byte transmitted first.
andrewboyson 10:f0854784e960 17 char senderHardwareAddress[6]; //nbytes: (ar$sha) Hardware address of sender of this packet, n from the ar$hln field.
andrewboyson 10:f0854784e960 18 uint32_t senderProtocolAddress; //mbytes: (ar$spa) Protocol address of sender of this packet, m from the ar$pln field.
andrewboyson 10:f0854784e960 19 char targetHardwareAddress[6]; //nbytes: (ar$tha) Hardware address of target of this packet (if known).
andrewboyson 10:f0854784e960 20 uint32_t targetProtocolAddress; //mbytes: (ar$tpa) Protocol address of target.
andrewboyson 10:f0854784e960 21 };
andrewboyson 10:f0854784e960 22 int ArpHandleReceivedPacket(char* pSrcMac, void * pPacket, int* pSize, char* pDstMac)
andrewboyson 10:f0854784e960 23 {
andrewboyson 10:f0854784e960 24 struct header* pHeader = (header*)pPacket;
andrewboyson 10:f0854784e960 25 int16_t hardwareType = NetToHost16(pHeader->hardwareType);
andrewboyson 10:f0854784e960 26 int16_t protocolType = NetToHost16(pHeader->protocolType);
andrewboyson 10:f0854784e960 27 int8_t hardwareLength = pHeader->hardwareLength;
andrewboyson 10:f0854784e960 28 int8_t protocolLength = pHeader->protocolLength;
andrewboyson 10:f0854784e960 29 int16_t opCode = NetToHost16(pHeader->opCode);
andrewboyson 10:f0854784e960 30 uint32_t targetProtocolAddress = pHeader->targetProtocolAddress;
andrewboyson 10:f0854784e960 31
andrewboyson 10:f0854784e960 32 if (hardwareType != ETHERNET ) return DO_NOTHING; //This is not ethernet
andrewboyson 10:f0854784e960 33 if (protocolType != IPV4 ) return DO_NOTHING; //This is not IPv4
andrewboyson 10:f0854784e960 34 if (hardwareLength != 6 ) return DO_NOTHING; //This is not a MAC hardware address
andrewboyson 10:f0854784e960 35 if (protocolLength != 4 ) return DO_NOTHING; //This is not an IPv4 IP address
andrewboyson 10:f0854784e960 36 if (opCode != REQUEST ) return DO_NOTHING; //This is not a request
andrewboyson 10:f0854784e960 37 if (targetProtocolAddress != DhcpLocalIp ) return DO_NOTHING; //This packet was not addressed to us
andrewboyson 10:f0854784e960 38
andrewboyson 10:f0854784e960 39 memcpy(pHeader->targetHardwareAddress, pHeader->senderHardwareAddress, 6);
andrewboyson 10:f0854784e960 40 pHeader->targetProtocolAddress = pHeader->senderProtocolAddress;
andrewboyson 13:9cd54f7db57a 41 memcpy(pHeader->senderHardwareAddress, MacLocal,6);
andrewboyson 10:f0854784e960 42 pHeader->senderProtocolAddress = DhcpLocalIp;
andrewboyson 10:f0854784e960 43 pHeader->opCode = NetToHost16(REPLY);
andrewboyson 10:f0854784e960 44
andrewboyson 10:f0854784e960 45 memcpy(pDstMac, pSrcMac, 6);
andrewboyson 10:f0854784e960 46
andrewboyson 10:f0854784e960 47 return UNICAST;
andrewboyson 10:f0854784e960 48 }