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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udp/dns/dnsreply.c@61:aad055f1b0d1, 2018-01-11 (annotated)

Committer:
andrewboyson
Date:
Thu Jan 11 17:38:21 2018 +0000
Revision:
61:aad055f1b0d1
Parent:
udp/dns/dnsreply.cpp@59:e0e556c8bd46
Child:
128:79052cb4a41c
Removed dependence on Mbed OS

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 61:aad055f1b0d1 1 #include <stdint.h>
andrewboyson 61:aad055f1b0d1 2 #include <stdbool.h>
andrewboyson 61:aad055f1b0d1 3 #include <string.h>
andrewboyson 61:aad055f1b0d1 4
andrewboyson 37:793b39683406 5 #include "log.h"
andrewboyson 37:793b39683406 6 #include "net.h"
andrewboyson 37:793b39683406 7 #include "action.h"
andrewboyson 37:793b39683406 8 #include "ip4.h"
andrewboyson 37:793b39683406 9 #include "ip6.h"
andrewboyson 50:492f2d2954e4 10 #include "nr4.h"
andrewboyson 50:492f2d2954e4 11 #include "nr6.h"
andrewboyson 37:793b39683406 12 #include "dns.h"
andrewboyson 37:793b39683406 13 #include "dnshdr.h"
andrewboyson 37:793b39683406 14 #include "dnsname.h"
andrewboyson 37:793b39683406 15 #include "dhcp.h"
andrewboyson 13:9cd54f7db57a 16
andrewboyson 37:793b39683406 17 bool DnsReplyTrace = false;
andrewboyson 13:9cd54f7db57a 18
andrewboyson 13:9cd54f7db57a 19 char DnsReplyRecordName[256];
andrewboyson 13:9cd54f7db57a 20 uint32_t DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 21 char DnsReplyRecordNameAsIp6[16];
andrewboyson 13:9cd54f7db57a 22 char DnsReplyName[64];
andrewboyson 13:9cd54f7db57a 23 uint32_t DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 24 char DnsReplyIp6[16];
andrewboyson 13:9cd54f7db57a 25
andrewboyson 58:d48c899e482f 26 static char* p;
andrewboyson 58:d48c899e482f 27 static char* pRecordName;
andrewboyson 58:d48c899e482f 28 static int recordType;
andrewboyson 58:d48c899e482f 29 static int recordDataLength;
andrewboyson 13:9cd54f7db57a 30 static char* pRecordData;
andrewboyson 13:9cd54f7db57a 31
andrewboyson 13:9cd54f7db57a 32 static int scanQuery()
andrewboyson 13:9cd54f7db57a 33 {
andrewboyson 13:9cd54f7db57a 34 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 35 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 36
andrewboyson 58:d48c899e482f 37 pRecordName = p;
andrewboyson 13:9cd54f7db57a 38 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 39
andrewboyson 13:9cd54f7db57a 40 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 41 recordType = *p++;
andrewboyson 13:9cd54f7db57a 42
andrewboyson 13:9cd54f7db57a 43 p += 2; //skip the class
andrewboyson 13:9cd54f7db57a 44
andrewboyson 13:9cd54f7db57a 45 return 0; //success
andrewboyson 13:9cd54f7db57a 46 }
andrewboyson 13:9cd54f7db57a 47
andrewboyson 13:9cd54f7db57a 48 static int scanAnswer()
andrewboyson 13:9cd54f7db57a 49 {
andrewboyson 13:9cd54f7db57a 50 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 51 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 52
andrewboyson 58:d48c899e482f 53 pRecordName = p;
andrewboyson 13:9cd54f7db57a 54 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 55
andrewboyson 13:9cd54f7db57a 56 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 57 recordType = *p++;
andrewboyson 13:9cd54f7db57a 58
andrewboyson 13:9cd54f7db57a 59 p += 6; //skip the class, TTL
andrewboyson 13:9cd54f7db57a 60 recordDataLength = 0;
andrewboyson 13:9cd54f7db57a 61 recordDataLength |= *p++ << 8;
andrewboyson 13:9cd54f7db57a 62 recordDataLength |= *p++;
andrewboyson 13:9cd54f7db57a 63
andrewboyson 13:9cd54f7db57a 64 pRecordData = p; //record the start of the data
andrewboyson 13:9cd54f7db57a 65
andrewboyson 13:9cd54f7db57a 66 p += recordDataLength; //Move to the start of the next record
andrewboyson 13:9cd54f7db57a 67
andrewboyson 13:9cd54f7db57a 68 return 0; //success
andrewboyson 13:9cd54f7db57a 69 }
andrewboyson 13:9cd54f7db57a 70 static void readAnswer()
andrewboyson 13:9cd54f7db57a 71 {
andrewboyson 13:9cd54f7db57a 72 DnsReplyRecordName[0] = 0;
andrewboyson 13:9cd54f7db57a 73 DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 74 DnsReplyRecordNameAsIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 75 DnsReplyName[0] = 0;
andrewboyson 13:9cd54f7db57a 76 DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 77 DnsReplyIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 78
andrewboyson 13:9cd54f7db57a 79 switch (recordType)
andrewboyson 13:9cd54f7db57a 80 {
andrewboyson 13:9cd54f7db57a 81 case DNS_RECORD_A:
andrewboyson 13:9cd54f7db57a 82 case DNS_RECORD_AAAA:
andrewboyson 13:9cd54f7db57a 83 case DNS_RECORD_PTR:
andrewboyson 15:6ca6778168b1 84 case DNS_RECORD_SRV:
andrewboyson 15:6ca6778168b1 85 case DNS_RECORD_TXT:
andrewboyson 13:9cd54f7db57a 86 break;
andrewboyson 43:bc028d5a6424 87 default:
andrewboyson 15:6ca6778168b1 88 return;
andrewboyson 15:6ca6778168b1 89 }
andrewboyson 13:9cd54f7db57a 90
andrewboyson 59:e0e556c8bd46 91 DnsNameDecodePtr(pRecordName, DnsReplyRecordName, sizeof(DnsReplyRecordName));
andrewboyson 58:d48c899e482f 92 DnsNameDecodeIp4(pRecordName, &DnsReplyRecordNameAsIp4);
andrewboyson 58:d48c899e482f 93 DnsNameDecodeIp6(pRecordName, DnsReplyRecordNameAsIp6);
andrewboyson 15:6ca6778168b1 94
andrewboyson 13:9cd54f7db57a 95 switch (recordType)
andrewboyson 13:9cd54f7db57a 96 {
andrewboyson 13:9cd54f7db57a 97 case DNS_RECORD_A:
andrewboyson 43:bc028d5a6424 98 if (recordDataLength != 4) return;
andrewboyson 13:9cd54f7db57a 99 memcpy(&DnsReplyIp4, pRecordData, 4);
andrewboyson 13:9cd54f7db57a 100 break;
andrewboyson 13:9cd54f7db57a 101 case DNS_RECORD_AAAA:
andrewboyson 43:bc028d5a6424 102 if (recordDataLength != 16) return;
andrewboyson 13:9cd54f7db57a 103 memcpy(DnsReplyIp6, pRecordData, 16);
andrewboyson 13:9cd54f7db57a 104 break;
andrewboyson 13:9cd54f7db57a 105 case DNS_RECORD_PTR:
andrewboyson 43:bc028d5a6424 106 if (recordDataLength > DNS_MAX_LABEL_LENGTH) return;
andrewboyson 59:e0e556c8bd46 107 DnsNameDecodePtr(pRecordData, DnsReplyName, sizeof(DnsReplyName));
andrewboyson 13:9cd54f7db57a 108 break;
andrewboyson 13:9cd54f7db57a 109 }
andrewboyson 13:9cd54f7db57a 110 }
andrewboyson 13:9cd54f7db57a 111
andrewboyson 32:679654f2d023 112 static void sendToDnsCache(int dnsProtocol)
andrewboyson 30:e34173b7585c 113 {
andrewboyson 32:679654f2d023 114 char strippedName[100];
andrewboyson 32:679654f2d023 115 if (DnsReplyRecordName[0]) DnsStripNameFromFullName(dnsProtocol, DnsReplyRecordName, sizeof(strippedName), strippedName);
andrewboyson 32:679654f2d023 116 if (DnsReplyName[0] ) DnsStripNameFromFullName(dnsProtocol, DnsReplyName , sizeof(strippedName), strippedName);
andrewboyson 32:679654f2d023 117
andrewboyson 50:492f2d2954e4 118 if (DnsReplyIp4 && DnsReplyRecordName[0]) Nr4AddIpRecord(DnsReplyIp4, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 119 if (DnsReplyIp6[0] && DnsReplyRecordName[0]) Nr6AddIpRecord(DnsReplyIp6, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 120 if (DnsReplyRecordNameAsIp4 && DnsReplyName[0] ) Nr4AddIpRecord(DnsReplyRecordNameAsIp4, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 121 if (DnsReplyRecordNameAsIp6[0] && DnsReplyName[0] ) Nr6AddIpRecord(DnsReplyRecordNameAsIp6, strippedName, dnsProtocol);
andrewboyson 30:e34173b7585c 122 }
andrewboyson 59:e0e556c8bd46 123 int DnsReplyHandle(void (*traceback)(void), int dnsProtocol)
andrewboyson 57:e0fb648acf48 124 {
andrewboyson 59:e0e556c8bd46 125
andrewboyson 57:e0fb648acf48 126 bool ok = true;
andrewboyson 57:e0fb648acf48 127 if (!DnsHdrAncount) ok = false;
andrewboyson 57:e0fb648acf48 128
andrewboyson 57:e0fb648acf48 129 p = DnsHdrData;
andrewboyson 57:e0fb648acf48 130
andrewboyson 57:e0fb648acf48 131 if (ok)
andrewboyson 57:e0fb648acf48 132 {
andrewboyson 57:e0fb648acf48 133 for (int q = 0; q < DnsHdrQdcount; q++)
andrewboyson 57:e0fb648acf48 134 {
andrewboyson 57:e0fb648acf48 135 if (scanQuery())
andrewboyson 57:e0fb648acf48 136 {
andrewboyson 57:e0fb648acf48 137 ok = false;
andrewboyson 57:e0fb648acf48 138 break;
andrewboyson 57:e0fb648acf48 139 }
andrewboyson 57:e0fb648acf48 140 }
andrewboyson 57:e0fb648acf48 141 }
andrewboyson 57:e0fb648acf48 142 if (ok)
andrewboyson 57:e0fb648acf48 143 {
andrewboyson 57:e0fb648acf48 144 for (int a = 0; a < DnsHdrAncount; a++)
andrewboyson 57:e0fb648acf48 145 {
andrewboyson 57:e0fb648acf48 146 if (scanAnswer())
andrewboyson 57:e0fb648acf48 147 {
andrewboyson 57:e0fb648acf48 148 ok = false;
andrewboyson 57:e0fb648acf48 149 break;
andrewboyson 57:e0fb648acf48 150 }
andrewboyson 57:e0fb648acf48 151 readAnswer();
andrewboyson 57:e0fb648acf48 152 sendToDnsCache(dnsProtocol);
andrewboyson 57:e0fb648acf48 153 }
andrewboyson 57:e0fb648acf48 154 }
andrewboyson 57:e0fb648acf48 155
andrewboyson 57:e0fb648acf48 156 NetTraceHostCheckIp6(DnsReplyIp6);
andrewboyson 57:e0fb648acf48 157 NetTraceHostCheckIp6(DnsReplyRecordNameAsIp6);
andrewboyson 57:e0fb648acf48 158
andrewboyson 57:e0fb648acf48 159 if (DnsReplyTrace || NetTraceHostGetMatched())
andrewboyson 37:793b39683406 160 {
andrewboyson 43:bc028d5a6424 161 if (NetTraceNewLine) Log("\r\n");
andrewboyson 43:bc028d5a6424 162 LogTimeF("DnsReply received\r\n");
andrewboyson 43:bc028d5a6424 163 if (NetTraceStack) traceback();
andrewboyson 37:793b39683406 164 DnsHdrLog(dnsProtocol);
andrewboyson 37:793b39683406 165 }
andrewboyson 13:9cd54f7db57a 166
andrewboyson 13:9cd54f7db57a 167
andrewboyson 13:9cd54f7db57a 168 return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 169 }