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@167:3ba4e3c49631, 2020-04-02 (annotated)

Committer:
andrewboyson
Date:
Thu Apr 02 19:08:25 2020 +0000
Revision:
167:3ba4e3c49631
Parent:
128:79052cb4a41c
Child:
170:96c637dc3f52
Modified resolution cache ajaxs to include the index

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 128:79052cb4a41c 15 #include "dnslabel.h"
andrewboyson 37:793b39683406 16 #include "dhcp.h"
andrewboyson 13:9cd54f7db57a 17
andrewboyson 37:793b39683406 18 bool DnsReplyTrace = false;
andrewboyson 13:9cd54f7db57a 19
andrewboyson 13:9cd54f7db57a 20 char DnsReplyRecordName[256];
andrewboyson 13:9cd54f7db57a 21 uint32_t DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 22 char DnsReplyRecordNameAsIp6[16];
andrewboyson 13:9cd54f7db57a 23 char DnsReplyName[64];
andrewboyson 13:9cd54f7db57a 24 uint32_t DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 25 char DnsReplyIp6[16];
andrewboyson 13:9cd54f7db57a 26
andrewboyson 58:d48c899e482f 27 static char* p;
andrewboyson 58:d48c899e482f 28 static char* pRecordName;
andrewboyson 58:d48c899e482f 29 static int recordType;
andrewboyson 58:d48c899e482f 30 static int recordDataLength;
andrewboyson 13:9cd54f7db57a 31 static char* pRecordData;
andrewboyson 13:9cd54f7db57a 32
andrewboyson 13:9cd54f7db57a 33 static int scanQuery()
andrewboyson 13:9cd54f7db57a 34 {
andrewboyson 13:9cd54f7db57a 35 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 36 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 37
andrewboyson 58:d48c899e482f 38 pRecordName = p;
andrewboyson 13:9cd54f7db57a 39 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 40
andrewboyson 13:9cd54f7db57a 41 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 42 recordType = *p++;
andrewboyson 13:9cd54f7db57a 43
andrewboyson 13:9cd54f7db57a 44 p += 2; //skip the class
andrewboyson 13:9cd54f7db57a 45
andrewboyson 13:9cd54f7db57a 46 return 0; //success
andrewboyson 13:9cd54f7db57a 47 }
andrewboyson 13:9cd54f7db57a 48
andrewboyson 13:9cd54f7db57a 49 static int scanAnswer()
andrewboyson 13:9cd54f7db57a 50 {
andrewboyson 13:9cd54f7db57a 51 int recordNameLength = DnsNameLength(p);
andrewboyson 43:bc028d5a6424 52 if (!recordNameLength) return -1; //failure
andrewboyson 13:9cd54f7db57a 53
andrewboyson 58:d48c899e482f 54 pRecordName = p;
andrewboyson 13:9cd54f7db57a 55 p += recordNameLength;
andrewboyson 13:9cd54f7db57a 56
andrewboyson 13:9cd54f7db57a 57 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 58 recordType = *p++;
andrewboyson 13:9cd54f7db57a 59
andrewboyson 13:9cd54f7db57a 60 p += 6; //skip the class, TTL
andrewboyson 13:9cd54f7db57a 61 recordDataLength = 0;
andrewboyson 13:9cd54f7db57a 62 recordDataLength |= *p++ << 8;
andrewboyson 13:9cd54f7db57a 63 recordDataLength |= *p++;
andrewboyson 13:9cd54f7db57a 64
andrewboyson 13:9cd54f7db57a 65 pRecordData = p; //record the start of the data
andrewboyson 13:9cd54f7db57a 66
andrewboyson 13:9cd54f7db57a 67 p += recordDataLength; //Move to the start of the next record
andrewboyson 13:9cd54f7db57a 68
andrewboyson 13:9cd54f7db57a 69 return 0; //success
andrewboyson 13:9cd54f7db57a 70 }
andrewboyson 13:9cd54f7db57a 71 static void readAnswer()
andrewboyson 13:9cd54f7db57a 72 {
andrewboyson 13:9cd54f7db57a 73 DnsReplyRecordName[0] = 0;
andrewboyson 13:9cd54f7db57a 74 DnsReplyRecordNameAsIp4 = 0;
andrewboyson 13:9cd54f7db57a 75 DnsReplyRecordNameAsIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 76 DnsReplyName[0] = 0;
andrewboyson 13:9cd54f7db57a 77 DnsReplyIp4 = 0;
andrewboyson 13:9cd54f7db57a 78 DnsReplyIp6[0] = 0;
andrewboyson 13:9cd54f7db57a 79
andrewboyson 13:9cd54f7db57a 80 switch (recordType)
andrewboyson 13:9cd54f7db57a 81 {
andrewboyson 13:9cd54f7db57a 82 case DNS_RECORD_A:
andrewboyson 13:9cd54f7db57a 83 case DNS_RECORD_AAAA:
andrewboyson 13:9cd54f7db57a 84 case DNS_RECORD_PTR:
andrewboyson 15:6ca6778168b1 85 case DNS_RECORD_SRV:
andrewboyson 15:6ca6778168b1 86 case DNS_RECORD_TXT:
andrewboyson 13:9cd54f7db57a 87 break;
andrewboyson 43:bc028d5a6424 88 default:
andrewboyson 15:6ca6778168b1 89 return;
andrewboyson 15:6ca6778168b1 90 }
andrewboyson 13:9cd54f7db57a 91
andrewboyson 59:e0e556c8bd46 92 DnsNameDecodePtr(pRecordName, DnsReplyRecordName, sizeof(DnsReplyRecordName));
andrewboyson 58:d48c899e482f 93 DnsNameDecodeIp4(pRecordName, &DnsReplyRecordNameAsIp4);
andrewboyson 58:d48c899e482f 94 DnsNameDecodeIp6(pRecordName, DnsReplyRecordNameAsIp6);
andrewboyson 15:6ca6778168b1 95
andrewboyson 13:9cd54f7db57a 96 switch (recordType)
andrewboyson 13:9cd54f7db57a 97 {
andrewboyson 13:9cd54f7db57a 98 case DNS_RECORD_A:
andrewboyson 43:bc028d5a6424 99 if (recordDataLength != 4) return;
andrewboyson 13:9cd54f7db57a 100 memcpy(&DnsReplyIp4, pRecordData, 4);
andrewboyson 13:9cd54f7db57a 101 break;
andrewboyson 13:9cd54f7db57a 102 case DNS_RECORD_AAAA:
andrewboyson 43:bc028d5a6424 103 if (recordDataLength != 16) return;
andrewboyson 13:9cd54f7db57a 104 memcpy(DnsReplyIp6, pRecordData, 16);
andrewboyson 13:9cd54f7db57a 105 break;
andrewboyson 13:9cd54f7db57a 106 case DNS_RECORD_PTR:
andrewboyson 43:bc028d5a6424 107 if (recordDataLength > DNS_MAX_LABEL_LENGTH) return;
andrewboyson 59:e0e556c8bd46 108 DnsNameDecodePtr(pRecordData, DnsReplyName, sizeof(DnsReplyName));
andrewboyson 13:9cd54f7db57a 109 break;
andrewboyson 13:9cd54f7db57a 110 }
andrewboyson 13:9cd54f7db57a 111 }
andrewboyson 13:9cd54f7db57a 112
andrewboyson 32:679654f2d023 113 static void sendToDnsCache(int dnsProtocol)
andrewboyson 30:e34173b7585c 114 {
andrewboyson 32:679654f2d023 115 char strippedName[100];
andrewboyson 128:79052cb4a41c 116 if (DnsReplyRecordName[0]) DnsLabelStripNameFromFullName(dnsProtocol, DnsReplyRecordName, sizeof(strippedName), strippedName);
andrewboyson 128:79052cb4a41c 117 if (DnsReplyName[0] ) DnsLabelStripNameFromFullName(dnsProtocol, DnsReplyName , sizeof(strippedName), strippedName);
andrewboyson 32:679654f2d023 118
andrewboyson 50:492f2d2954e4 119 if (DnsReplyIp4 && DnsReplyRecordName[0]) Nr4AddIpRecord(DnsReplyIp4, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 120 if (DnsReplyIp6[0] && DnsReplyRecordName[0]) Nr6AddIpRecord(DnsReplyIp6, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 121 if (DnsReplyRecordNameAsIp4 && DnsReplyName[0] ) Nr4AddIpRecord(DnsReplyRecordNameAsIp4, strippedName, dnsProtocol);
andrewboyson 50:492f2d2954e4 122 if (DnsReplyRecordNameAsIp6[0] && DnsReplyName[0] ) Nr6AddIpRecord(DnsReplyRecordNameAsIp6, strippedName, dnsProtocol);
andrewboyson 30:e34173b7585c 123 }
andrewboyson 59:e0e556c8bd46 124 int DnsReplyHandle(void (*traceback)(void), int dnsProtocol)
andrewboyson 57:e0fb648acf48 125 {
andrewboyson 59:e0e556c8bd46 126
andrewboyson 57:e0fb648acf48 127 bool ok = true;
andrewboyson 57:e0fb648acf48 128 if (!DnsHdrAncount) ok = false;
andrewboyson 57:e0fb648acf48 129
andrewboyson 57:e0fb648acf48 130 p = DnsHdrData;
andrewboyson 57:e0fb648acf48 131
andrewboyson 57:e0fb648acf48 132 if (ok)
andrewboyson 57:e0fb648acf48 133 {
andrewboyson 57:e0fb648acf48 134 for (int q = 0; q < DnsHdrQdcount; q++)
andrewboyson 57:e0fb648acf48 135 {
andrewboyson 57:e0fb648acf48 136 if (scanQuery())
andrewboyson 57:e0fb648acf48 137 {
andrewboyson 57:e0fb648acf48 138 ok = false;
andrewboyson 57:e0fb648acf48 139 break;
andrewboyson 57:e0fb648acf48 140 }
andrewboyson 57:e0fb648acf48 141 }
andrewboyson 57:e0fb648acf48 142 }
andrewboyson 57:e0fb648acf48 143 if (ok)
andrewboyson 57:e0fb648acf48 144 {
andrewboyson 57:e0fb648acf48 145 for (int a = 0; a < DnsHdrAncount; a++)
andrewboyson 57:e0fb648acf48 146 {
andrewboyson 57:e0fb648acf48 147 if (scanAnswer())
andrewboyson 57:e0fb648acf48 148 {
andrewboyson 57:e0fb648acf48 149 ok = false;
andrewboyson 57:e0fb648acf48 150 break;
andrewboyson 57:e0fb648acf48 151 }
andrewboyson 57:e0fb648acf48 152 readAnswer();
andrewboyson 57:e0fb648acf48 153 sendToDnsCache(dnsProtocol);
andrewboyson 57:e0fb648acf48 154 }
andrewboyson 57:e0fb648acf48 155 }
andrewboyson 57:e0fb648acf48 156
andrewboyson 57:e0fb648acf48 157 NetTraceHostCheckIp6(DnsReplyIp6);
andrewboyson 57:e0fb648acf48 158 NetTraceHostCheckIp6(DnsReplyRecordNameAsIp6);
andrewboyson 57:e0fb648acf48 159
andrewboyson 57:e0fb648acf48 160 if (DnsReplyTrace || NetTraceHostGetMatched())
andrewboyson 37:793b39683406 161 {
andrewboyson 43:bc028d5a6424 162 if (NetTraceNewLine) Log("\r\n");
andrewboyson 43:bc028d5a6424 163 LogTimeF("DnsReply received\r\n");
andrewboyson 43:bc028d5a6424 164 if (NetTraceStack) traceback();
andrewboyson 37:793b39683406 165 DnsHdrLog(dnsProtocol);
andrewboyson 37:793b39683406 166 }
andrewboyson 13:9cd54f7db57a 167
andrewboyson 13:9cd54f7db57a 168
andrewboyson 13:9cd54f7db57a 169 return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 170 }