Andrew Boyson / net

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

Dependents:   oldheating gps motorhome heating

eth/arp.cpp@35:93c39d260a83, 2017-09-22 (annotated)

Committer:
andrewboyson
Date:
Fri Sep 22 13:55:56 2017 +0000
Revision:
35:93c39d260a83
Parent:
30:e34173b7585c
Child:
36:900e24b27bfb
Added name resolution and address resolution

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 14:e75a59c1123d 4 #include "eth.h"
andrewboyson 13:9cd54f7db57a 5 #include "mac.h"
andrewboyson 10:f0854784e960 6 #include "dhcp.h"
andrewboyson 22:914b970356f0 7 #include "ar.h"
andrewboyson 35:93c39d260a83 8 #include "nr.h"
andrewboyson 22:914b970356f0 9 #include "io.h"
andrewboyson 10:f0854784e960 10
andrewboyson 10:f0854784e960 11 #define REQUEST 1
andrewboyson 10:f0854784e960 12 #define REPLY 2
andrewboyson 10:f0854784e960 13
andrewboyson 35:93c39d260a83 14 #define DEBUG false
andrewboyson 35:93c39d260a83 15
andrewboyson 22:914b970356f0 16 uint32_t ArpAddressToResolve;
andrewboyson 22:914b970356f0 17 bool ArpResolveRequestFlag = false;
andrewboyson 22:914b970356f0 18
andrewboyson 10:f0854784e960 19 __packed struct header
andrewboyson 10:f0854784e960 20 {
andrewboyson 10:f0854784e960 21 int16_t hardwareType; //16.bit: (ar$hrd) Hardware address space (e.g., Ethernet, Packet Radio Net). Always 1.
andrewboyson 10:f0854784e960 22 int16_t protocolType; //16.bit: (ar$pro) Protocol address space. For Ethernet hardware, this is from the set of type fields ether_typ$<protocol>. As held in eth.h, eg IPv4 = 0x8000.
andrewboyson 10:f0854784e960 23 int8_t hardwareLength; // 8.bit: (ar$hln) byte length of each hardware address. Always 6 bytes.
andrewboyson 10:f0854784e960 24 int8_t protocolLength; // 8.bit: (ar$pln) byte length of each protocol address. Always 4 bytes.
andrewboyson 10:f0854784e960 25 int16_t opCode; //16.bit: (ar$op) opcode (ares_op$REQUEST = 1 | ares_op$REPLY = 2), high byte transmitted first.
andrewboyson 10:f0854784e960 26 char senderHardwareAddress[6]; //nbytes: (ar$sha) Hardware address of sender of this packet, n from the ar$hln field.
andrewboyson 10:f0854784e960 27 uint32_t senderProtocolAddress; //mbytes: (ar$spa) Protocol address of sender of this packet, m from the ar$pln field.
andrewboyson 10:f0854784e960 28 char targetHardwareAddress[6]; //nbytes: (ar$tha) Hardware address of target of this packet (if known).
andrewboyson 10:f0854784e960 29 uint32_t targetProtocolAddress; //mbytes: (ar$tpa) Protocol address of target.
andrewboyson 10:f0854784e960 30 };
andrewboyson 10:f0854784e960 31 int ArpHandleReceivedPacket(char* pSrcMac, void * pPacket, int* pSize, char* pDstMac)
andrewboyson 10:f0854784e960 32 {
andrewboyson 10:f0854784e960 33 struct header* pHeader = (header*)pPacket;
andrewboyson 10:f0854784e960 34 int16_t hardwareType = NetToHost16(pHeader->hardwareType);
andrewboyson 10:f0854784e960 35 int16_t protocolType = NetToHost16(pHeader->protocolType);
andrewboyson 10:f0854784e960 36 int8_t hardwareLength = pHeader->hardwareLength;
andrewboyson 10:f0854784e960 37 int8_t protocolLength = pHeader->protocolLength;
andrewboyson 10:f0854784e960 38 int16_t opCode = NetToHost16(pHeader->opCode);
andrewboyson 10:f0854784e960 39 uint32_t targetProtocolAddress = pHeader->targetProtocolAddress;
andrewboyson 10:f0854784e960 40
andrewboyson 10:f0854784e960 41 if (hardwareType != ETHERNET ) return DO_NOTHING; //This is not ethernet
andrewboyson 10:f0854784e960 42 if (protocolType != IPV4 ) return DO_NOTHING; //This is not IPv4
andrewboyson 10:f0854784e960 43 if (hardwareLength != 6 ) return DO_NOTHING; //This is not a MAC hardware address
andrewboyson 10:f0854784e960 44 if (protocolLength != 4 ) return DO_NOTHING; //This is not an IPv4 IP address
andrewboyson 10:f0854784e960 45 if (targetProtocolAddress != DhcpLocalIp ) return DO_NOTHING; //This packet was not addressed to us
andrewboyson 10:f0854784e960 46
andrewboyson 22:914b970356f0 47 switch (opCode)
andrewboyson 22:914b970356f0 48 {
andrewboyson 22:914b970356f0 49 case REQUEST:
andrewboyson 22:914b970356f0 50 memcpy(pHeader->targetHardwareAddress, pHeader->senderHardwareAddress, 6);
andrewboyson 22:914b970356f0 51 pHeader->targetProtocolAddress = pHeader->senderProtocolAddress;
andrewboyson 22:914b970356f0 52 memcpy(pHeader->senderHardwareAddress, MacLocal,6);
andrewboyson 22:914b970356f0 53 pHeader->senderProtocolAddress = DhcpLocalIp;
andrewboyson 22:914b970356f0 54 pHeader->opCode = NetToHost16(REPLY);
andrewboyson 22:914b970356f0 55 memcpy(pDstMac, pSrcMac, 6);
andrewboyson 22:914b970356f0 56 return UNICAST;
andrewboyson 22:914b970356f0 57 case REPLY:
andrewboyson 35:93c39d260a83 58 ArAddIp4Record(pHeader->senderHardwareAddress, pHeader->senderProtocolAddress);
andrewboyson 35:93c39d260a83 59 NrMakeRequestForNameFromIp4(pHeader->senderProtocolAddress);
andrewboyson 22:914b970356f0 60 return DO_NOTHING;
andrewboyson 22:914b970356f0 61 default:
andrewboyson 22:914b970356f0 62 return DO_NOTHING;
andrewboyson 22:914b970356f0 63 }
andrewboyson 22:914b970356f0 64 }
andrewboyson 22:914b970356f0 65 int ArpPollForPacketToSend(void* pPacket, int* pSize)
andrewboyson 22:914b970356f0 66 {
andrewboyson 22:914b970356f0 67 if (!ArpResolveRequestFlag) return DO_NOTHING;
andrewboyson 22:914b970356f0 68 ArpResolveRequestFlag = false;
andrewboyson 22:914b970356f0 69
andrewboyson 22:914b970356f0 70 struct header* pHeader = (header*)pPacket;
andrewboyson 22:914b970356f0 71
andrewboyson 22:914b970356f0 72 pHeader->hardwareType = NetToHost16(ETHERNET);
andrewboyson 22:914b970356f0 73 pHeader->protocolType = NetToHost16(IPV4);
andrewboyson 22:914b970356f0 74 pHeader->hardwareLength = 6;
andrewboyson 22:914b970356f0 75 pHeader->protocolLength = 4;
andrewboyson 22:914b970356f0 76 pHeader->opCode = NetToHost16(REQUEST);
andrewboyson 22:914b970356f0 77
andrewboyson 22:914b970356f0 78 memset(pHeader->targetHardwareAddress, 0, 6);
andrewboyson 22:914b970356f0 79 pHeader->targetProtocolAddress = ArpAddressToResolve;
andrewboyson 13:9cd54f7db57a 80 memcpy(pHeader->senderHardwareAddress, MacLocal,6);
andrewboyson 10:f0854784e960 81 pHeader->senderProtocolAddress = DhcpLocalIp;
andrewboyson 22:914b970356f0 82
andrewboyson 22:914b970356f0 83 *pSize = sizeof(header);
andrewboyson 10:f0854784e960 84
andrewboyson 22:914b970356f0 85 return BROADCAST;
andrewboyson 35:93c39d260a83 86 }