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udp/dns/dnsreply.cpp@48:952dddb74b8b, 2017-10-31 (annotated)

Committer:
andrewboyson
Date:
Tue Oct 31 21:25:09 2017 +0000
Revision:
48:952dddb74b8b
Parent:
43:bc028d5a6424
Child:
50:492f2d2954e4
Split address resolution into AR4 and AR6. Corrected issue clearing a AR6 record.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 37:793b39683406 1 #include "mbed.h"
andrewboyson 37:793b39683406 2 #include "log.h"
andrewboyson 37:793b39683406 3 #include "net.h"
andrewboyson 37:793b39683406 4 #include "action.h"
andrewboyson 37:793b39683406 5 #include "ip4.h"
andrewboyson 37:793b39683406 6 #include "ip6.h"
andrewboyson 37:793b39683406 7 #include "nr.h"
andrewboyson 37:793b39683406 8 #include "dns.h"
andrewboyson 37:793b39683406 9 #include "dnshdr.h"
andrewboyson 37:793b39683406 10 #include "dnsname.h"
andrewboyson 37:793b39683406 11 #include "dhcp.h"
andrewboyson 13:9cd54f7db57a 12
andrewboyson 37:793b39683406 13 bool DnsReplyTrace = false;
andrewboyson 13:9cd54f7db57a 14
andrewboyson 13:9cd54f7db57a 15 char DnsReplyRecordName[256];
andrewboyson 13:9cd54f7db57a 16 uint32_t DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 17 char DnsReplyRecordNameAsIp6[16];
andrewboyson 13:9cd54f7db57a 18 char DnsReplyName[64];
andrewboyson 13:9cd54f7db57a 19 uint32_t DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 20 char DnsReplyIp6[16];
andrewboyson 13:9cd54f7db57a 21
andrewboyson 13:9cd54f7db57a 22 static char *p;
andrewboyson 13:9cd54f7db57a 23 static int recordNameOffset;
andrewboyson 13:9cd54f7db57a 24 static int recordType;
andrewboyson 13:9cd54f7db57a 25 static int recordDataLength;
andrewboyson 13:9cd54f7db57a 26 static char* pRecordData;
andrewboyson 13:9cd54f7db57a 27
andrewboyson 13:9cd54f7db57a 28 static int scanQuery()
andrewboyson 13:9cd54f7db57a 29 {
andrewboyson 13:9cd54f7db57a 30 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 31 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 32
andrewboyson 13:9cd54f7db57a 33 recordNameOffset = DnsNameIndexFromPointer(p);
andrewboyson 13:9cd54f7db57a 34 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 35
andrewboyson 13:9cd54f7db57a 36 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 37 recordType = *p++;
andrewboyson 13:9cd54f7db57a 38
andrewboyson 13:9cd54f7db57a 39 p += 2; //skip the class
andrewboyson 13:9cd54f7db57a 40
andrewboyson 13:9cd54f7db57a 41 return 0; //success
andrewboyson 13:9cd54f7db57a 42 }
andrewboyson 13:9cd54f7db57a 43
andrewboyson 13:9cd54f7db57a 44 static int scanAnswer()
andrewboyson 13:9cd54f7db57a 45 {
andrewboyson 13:9cd54f7db57a 46 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 47 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 48
andrewboyson 13:9cd54f7db57a 49 recordNameOffset = DnsNameIndexFromPointer(p);
andrewboyson 13:9cd54f7db57a 50 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 51
andrewboyson 13:9cd54f7db57a 52 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 53 recordType = *p++;
andrewboyson 13:9cd54f7db57a 54
andrewboyson 13:9cd54f7db57a 55 p += 6; //skip the class, TTL
andrewboyson 13:9cd54f7db57a 56 recordDataLength = 0;
andrewboyson 13:9cd54f7db57a 57 recordDataLength |= *p++ << 8;
andrewboyson 13:9cd54f7db57a 58 recordDataLength |= *p++;
andrewboyson 13:9cd54f7db57a 59
andrewboyson 13:9cd54f7db57a 60 pRecordData = p; //record the start of the data
andrewboyson 13:9cd54f7db57a 61
andrewboyson 13:9cd54f7db57a 62 p += recordDataLength; //Move to the start of the next record
andrewboyson 13:9cd54f7db57a 63
andrewboyson 13:9cd54f7db57a 64 return 0; //success
andrewboyson 13:9cd54f7db57a 65 }
andrewboyson 13:9cd54f7db57a 66 static void readAnswer()
andrewboyson 13:9cd54f7db57a 67 {
andrewboyson 13:9cd54f7db57a 68 DnsReplyRecordName[0] = 0;
andrewboyson 13:9cd54f7db57a 69 DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 70 DnsReplyRecordNameAsIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 71 DnsReplyName[0] = 0;
andrewboyson 13:9cd54f7db57a 72 DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 73 DnsReplyIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 74
andrewboyson 13:9cd54f7db57a 75 switch (recordType)
andrewboyson 13:9cd54f7db57a 76 {
andrewboyson 13:9cd54f7db57a 77 case DNS_RECORD_A:
andrewboyson 13:9cd54f7db57a 78 case DNS_RECORD_AAAA:
andrewboyson 13:9cd54f7db57a 79 case DNS_RECORD_PTR:
andrewboyson 15:6ca6778168b1 80 case DNS_RECORD_SRV:
andrewboyson 15:6ca6778168b1 81 case DNS_RECORD_TXT:
andrewboyson 13:9cd54f7db57a 82 break;
andrewboyson 43:bc028d5a6424 83 default:
andrewboyson 15:6ca6778168b1 84 return;
andrewboyson 15:6ca6778168b1 85 }
andrewboyson 13:9cd54f7db57a 86
andrewboyson 37:793b39683406 87 DnsNameDecodePtr(recordNameOffset, sizeof(DnsReplyRecordName), DnsReplyRecordName);
andrewboyson 13:9cd54f7db57a 88 DnsNameDecodeIp4(recordNameOffset, &DnsReplyRecordNameAsIp4);
andrewboyson 13:9cd54f7db57a 89 DnsNameDecodeIp6(recordNameOffset, DnsReplyRecordNameAsIp6);
andrewboyson 15:6ca6778168b1 90
andrewboyson 13:9cd54f7db57a 91 switch (recordType)
andrewboyson 13:9cd54f7db57a 92 {
andrewboyson 13:9cd54f7db57a 93 case DNS_RECORD_A:
andrewboyson 43:bc028d5a6424 94 if (recordDataLength != 4) return;
andrewboyson 13:9cd54f7db57a 95 memcpy(&DnsReplyIp4, pRecordData, 4);
andrewboyson 13:9cd54f7db57a 96 break;
andrewboyson 13:9cd54f7db57a 97 case DNS_RECORD_AAAA:
andrewboyson 43:bc028d5a6424 98 if (recordDataLength != 16) return;
andrewboyson 13:9cd54f7db57a 99 memcpy(DnsReplyIp6, pRecordData, 16);
andrewboyson 13:9cd54f7db57a 100 break;
andrewboyson 13:9cd54f7db57a 101 case DNS_RECORD_PTR:
andrewboyson 43:bc028d5a6424 102 if (recordDataLength > DNS_MAX_LABEL_LENGTH) return;
andrewboyson 37:793b39683406 103 DnsNameDecodePtr(DnsNameIndexFromPointer(pRecordData), sizeof(DnsReplyName), DnsReplyName);
andrewboyson 13:9cd54f7db57a 104 break;
andrewboyson 13:9cd54f7db57a 105 }
andrewboyson 13:9cd54f7db57a 106 }
andrewboyson 13:9cd54f7db57a 107
andrewboyson 32:679654f2d023 108 static void sendToDnsCache(int dnsProtocol)
andrewboyson 30:e34173b7585c 109 {
andrewboyson 32:679654f2d023 110 char strippedName[100];
andrewboyson 32:679654f2d023 111 if (DnsReplyRecordName[0]) DnsStripNameFromFullName(dnsProtocol, DnsReplyRecordName, sizeof(strippedName), strippedName);
andrewboyson 32:679654f2d023 112 if (DnsReplyName[0] ) DnsStripNameFromFullName(dnsProtocol, DnsReplyName , sizeof(strippedName), strippedName);
andrewboyson 32:679654f2d023 113
andrewboyson 35:93c39d260a83 114 if (DnsReplyIp4 && DnsReplyRecordName[0]) NrAddIp4Record(DnsReplyIp4, strippedName, dnsProtocol);
andrewboyson 35:93c39d260a83 115 if (DnsReplyIp6[0] && DnsReplyRecordName[0]) NrAddIp6Record(DnsReplyIp6, strippedName, dnsProtocol);
andrewboyson 35:93c39d260a83 116 if (DnsReplyRecordNameAsIp4 && DnsReplyName[0] ) NrAddIp4Record(DnsReplyRecordNameAsIp4, strippedName, dnsProtocol);
andrewboyson 35:93c39d260a83 117 if (DnsReplyRecordNameAsIp6[0] && DnsReplyName[0] ) NrAddIp6Record(DnsReplyRecordNameAsIp6, strippedName, dnsProtocol);
andrewboyson 30:e34173b7585c 118 }
andrewboyson 37:793b39683406 119 int DnsReplyHandle(void (*traceback)(void), int dnsProtocol, int *pSize)
andrewboyson 13:9cd54f7db57a 120 {
andrewboyson 13:9cd54f7db57a 121 if (!DnsHdrAncount) return DO_NOTHING;
andrewboyson 37:793b39683406 122 if (DnsReplyTrace)
andrewboyson 37:793b39683406 123 {
andrewboyson 43:bc028d5a6424 124 if (NetTraceNewLine) Log("\r\n");
andrewboyson 43:bc028d5a6424 125 LogTimeF("DnsReply received\r\n");
andrewboyson 43:bc028d5a6424 126 if (NetTraceStack) traceback();
andrewboyson 37:793b39683406 127 DnsHdrLog(dnsProtocol);
andrewboyson 37:793b39683406 128 }
andrewboyson 13:9cd54f7db57a 129
andrewboyson 13:9cd54f7db57a 130 p = DnsHdrData;
andrewboyson 13:9cd54f7db57a 131
andrewboyson 13:9cd54f7db57a 132 for (int q = 0; q < DnsHdrQdcount; q++)
andrewboyson 13:9cd54f7db57a 133 {
andrewboyson 13:9cd54f7db57a 134 if (scanQuery()) return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 135 }
andrewboyson 13:9cd54f7db57a 136 for (int a = 0; a < DnsHdrAncount; a++)
andrewboyson 13:9cd54f7db57a 137 {
andrewboyson 13:9cd54f7db57a 138 if (scanAnswer()) return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 139 readAnswer();
andrewboyson 32:679654f2d023 140 sendToDnsCache(dnsProtocol);
andrewboyson 13:9cd54f7db57a 141 }
andrewboyson 13:9cd54f7db57a 142
andrewboyson 13:9cd54f7db57a 143 return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 144 }