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ip4/icmp/icmp4.cpp@59:e0e556c8bd46, 2017-12-14 (annotated)

Committer:
andrewboyson
Date:
Thu Dec 14 20:55:40 2017 +0000
Revision:
59:e0e556c8bd46
Parent:
52:fbc5a46b5e16 
Added buffer length to help avoid over runs

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 43:bc028d5a6424 1 #include "mbed.h"
andrewboyson 43:bc028d5a6424 2 #include "log.h"
andrewboyson 43:bc028d5a6424 3 #include "net.h"
andrewboyson 43:bc028d5a6424 4 #include "action.h"
andrewboyson 43:bc028d5a6424 5 #include "ip4.h"
andrewboyson 43:bc028d5a6424 6 #include "dhcp.h"
andrewboyson 43:bc028d5a6424 7 #include "echo4.h"
andrewboyson 43:bc028d5a6424 8
andrewboyson 43:bc028d5a6424 9 #define ECHO_REPLY 0
andrewboyson 43:bc028d5a6424 10 #define UNREACHABLE 3
andrewboyson 43:bc028d5a6424 11 #define REDIRECT 5
andrewboyson 43:bc028d5a6424 12 #define ECHO_REQUEST 8
andrewboyson 43:bc028d5a6424 13
andrewboyson 43:bc028d5a6424 14 __packed struct header
andrewboyson 43:bc028d5a6424 15 {
andrewboyson 43:bc028d5a6424 16 uint8_t type;
andrewboyson 43:bc028d5a6424 17 uint8_t code;
andrewboyson 43:bc028d5a6424 18 uint16_t checksum;
andrewboyson 43:bc028d5a6424 19 };
andrewboyson 43:bc028d5a6424 20 static uint8_t type;
andrewboyson 43:bc028d5a6424 21 static uint8_t code;
andrewboyson 43:bc028d5a6424 22 static uint16_t checksum;
andrewboyson 43:bc028d5a6424 23 static uint16_t calculated;
andrewboyson 43:bc028d5a6424 24
andrewboyson 47:73af5c0b0dc2 25 static void logType(uint16_t type)
andrewboyson 43:bc028d5a6424 26 {
andrewboyson 43:bc028d5a6424 27 switch (type)
andrewboyson 43:bc028d5a6424 28 {
andrewboyson 47:73af5c0b0dc2 29 case ECHO_REPLY: Log ("Echo Reply" ); break;
andrewboyson 47:73af5c0b0dc2 30 case ECHO_REQUEST: Log ("Echo Request" ); break;
andrewboyson 47:73af5c0b0dc2 31 default: LogF("Unknown type %d", type); break;
andrewboyson 43:bc028d5a6424 32 }
andrewboyson 43:bc028d5a6424 33 }
andrewboyson 43:bc028d5a6424 34 static void logHeader()
andrewboyson 47:73af5c0b0dc2 35 {
andrewboyson 43:bc028d5a6424 36 if (NetTraceVerbose)
andrewboyson 43:bc028d5a6424 37 {
andrewboyson 43:bc028d5a6424 38 Log ("ICMP4 header\r\n");
andrewboyson 47:73af5c0b0dc2 39 LogF(" Type "); logType(type); Log("\r\n");
andrewboyson 43:bc028d5a6424 40 LogF(" Code %u\r\n", code);
andrewboyson 43:bc028d5a6424 41 LogF(" Checksum (hex) %04hX\r\n", checksum);
andrewboyson 43:bc028d5a6424 42 LogF(" Calculated %04hX\r\n", calculated);
andrewboyson 43:bc028d5a6424 43 }
andrewboyson 43:bc028d5a6424 44 else
andrewboyson 43:bc028d5a6424 45 {
andrewboyson 43:bc028d5a6424 46 Log("ICMP4 header ");
andrewboyson 47:73af5c0b0dc2 47 logType(type);
andrewboyson 43:bc028d5a6424 48 Log("\r\n");
andrewboyson 43:bc028d5a6424 49 }
andrewboyson 43:bc028d5a6424 50 }
andrewboyson 43:bc028d5a6424 51 static void readHeader(void* pPacket, int size)
andrewboyson 43:bc028d5a6424 52 {
andrewboyson 43:bc028d5a6424 53 struct header* pHeader = (header*)pPacket;
andrewboyson 43:bc028d5a6424 54 type = pHeader->type;
andrewboyson 43:bc028d5a6424 55 code = pHeader->code;
andrewboyson 43:bc028d5a6424 56 checksum = NetToHost16(pHeader->checksum);
andrewboyson 43:bc028d5a6424 57 calculated = NetCheckSum(size, pPacket);
andrewboyson 43:bc028d5a6424 58 }
andrewboyson 43:bc028d5a6424 59 static void writeHeader(void* pPacket, int size)
andrewboyson 43:bc028d5a6424 60 {
andrewboyson 43:bc028d5a6424 61 struct header* pHeader = (header*)pPacket;
andrewboyson 43:bc028d5a6424 62 pHeader->type = type;
andrewboyson 43:bc028d5a6424 63 pHeader->code = code;
andrewboyson 43:bc028d5a6424 64 pHeader->checksum = 0;
andrewboyson 43:bc028d5a6424 65 pHeader->checksum = NetCheckSum(size, pPacket);
andrewboyson 43:bc028d5a6424 66 calculated = 0;
andrewboyson 43:bc028d5a6424 67 }
andrewboyson 43:bc028d5a6424 68 static void (*pTraceBack)(void);
andrewboyson 43:bc028d5a6424 69 static void trace()
andrewboyson 43:bc028d5a6424 70 {
andrewboyson 43:bc028d5a6424 71 pTraceBack();
andrewboyson 43:bc028d5a6424 72 logHeader();
andrewboyson 43:bc028d5a6424 73 }
andrewboyson 59:e0e556c8bd46 74 int Icmp4HandleReceivedPacket(void (*traceback)(void), void* pPacketRx, int sizeRx, void* pPacketTx, int* pSizeTx, uint32_t* pSrcIp, uint32_t* pDstIp)
andrewboyson 43:bc028d5a6424 75 {
andrewboyson 43:bc028d5a6424 76 pTraceBack = traceback;
andrewboyson 43:bc028d5a6424 77
andrewboyson 59:e0e556c8bd46 78 readHeader(pPacketRx, sizeRx);
andrewboyson 59:e0e556c8bd46 79
andrewboyson 59:e0e556c8bd46 80 int dataLengthRx = sizeRx - sizeof(header);
andrewboyson 59:e0e556c8bd46 81 int dataLengthTx = *pSizeTx - sizeof(header);
andrewboyson 59:e0e556c8bd46 82 char* pPayloadRx = (char*)pPacketRx + sizeof(header);
andrewboyson 59:e0e556c8bd46 83 char* pPayloadTx = (char*)pPacketTx + sizeof(header);
andrewboyson 43:bc028d5a6424 84
andrewboyson 43:bc028d5a6424 85 int action = DO_NOTHING;
andrewboyson 43:bc028d5a6424 86 switch (type)
andrewboyson 43:bc028d5a6424 87 {
andrewboyson 43:bc028d5a6424 88 case ECHO_REQUEST:
andrewboyson 59:e0e556c8bd46 89 action = Echo4HandleRequest(trace, &type, &code, pPayloadRx, dataLengthRx, pPayloadTx, &dataLengthTx);
andrewboyson 43:bc028d5a6424 90 break;
andrewboyson 43:bc028d5a6424 91 case UNREACHABLE:
andrewboyson 43:bc028d5a6424 92 return DO_NOTHING;
andrewboyson 43:bc028d5a6424 93 case REDIRECT:
andrewboyson 43:bc028d5a6424 94 return DO_NOTHING;
andrewboyson 43:bc028d5a6424 95 default:
andrewboyson 43:bc028d5a6424 96 LogTimeF("ICMP4 packet type %d unknown\r\n", type);
andrewboyson 43:bc028d5a6424 97 return DO_NOTHING;
andrewboyson 43:bc028d5a6424 98 }
andrewboyson 43:bc028d5a6424 99 if (!action) return DO_NOTHING;
andrewboyson 43:bc028d5a6424 100
andrewboyson 43:bc028d5a6424 101 *pDstIp = *pSrcIp;
andrewboyson 43:bc028d5a6424 102 *pSrcIp = DhcpLocalIp;
andrewboyson 43:bc028d5a6424 103
andrewboyson 59:e0e556c8bd46 104 *pSizeTx = sizeof(header) + dataLengthTx;
andrewboyson 43:bc028d5a6424 105
andrewboyson 59:e0e556c8bd46 106 writeHeader(pPacketTx, *pSizeTx);
andrewboyson 43:bc028d5a6424 107
andrewboyson 43:bc028d5a6424 108 if (ActionGetTracePart(action)) logHeader();
andrewboyson 43:bc028d5a6424 109
andrewboyson 43:bc028d5a6424 110 return action;
andrewboyson 43:bc028d5a6424 111 }