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
udp/dns/dnshdr.cpp@59:e0e556c8bd46, 2017-12-14 (annotated)
- Committer:
- andrewboyson
- Date:
- Thu Dec 14 20:55:40 2017 +0000
- Revision:
- 59:e0e556c8bd46
- Parent:
- 58:d48c899e482f
Added buffer length to help avoid over runs
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
andrewboyson | 13:9cd54f7db57a | 1 | #include "mbed.h" |
andrewboyson | 13:9cd54f7db57a | 2 | #include "dns.h" |
andrewboyson | 13:9cd54f7db57a | 3 | #include "net.h" |
andrewboyson | 13:9cd54f7db57a | 4 | #include "log.h" |
andrewboyson | 14:e75a59c1123d | 5 | #include "net.h" |
andrewboyson | 14:e75a59c1123d | 6 | #include "eth.h" |
andrewboyson | 49:1a6336f2b3f9 | 7 | #include "ip4addr.h" |
andrewboyson | 49:1a6336f2b3f9 | 8 | #include "ip6addr.h" |
andrewboyson | 14:e75a59c1123d | 9 | #include "udp.h" |
andrewboyson | 37:793b39683406 | 10 | #include "dnsname.h" |
andrewboyson | 13:9cd54f7db57a | 11 | |
andrewboyson | 13:9cd54f7db57a | 12 | #define HEADER_LENGTH 12 |
andrewboyson | 13:9cd54f7db57a | 13 | |
andrewboyson | 13:9cd54f7db57a | 14 | __packed struct header |
andrewboyson | 13:9cd54f7db57a | 15 | { |
andrewboyson | 13:9cd54f7db57a | 16 | uint16_t id; |
andrewboyson | 13:9cd54f7db57a | 17 | uint8_t uflags; |
andrewboyson | 13:9cd54f7db57a | 18 | uint8_t lflags; |
andrewboyson | 13:9cd54f7db57a | 19 | |
andrewboyson | 13:9cd54f7db57a | 20 | uint16_t qdcount; |
andrewboyson | 13:9cd54f7db57a | 21 | uint16_t ancount; |
andrewboyson | 13:9cd54f7db57a | 22 | uint16_t nscount; |
andrewboyson | 13:9cd54f7db57a | 23 | uint16_t arcount; |
andrewboyson | 13:9cd54f7db57a | 24 | }; |
andrewboyson | 13:9cd54f7db57a | 25 | |
andrewboyson | 13:9cd54f7db57a | 26 | uint16_t DnsHdrId; |
andrewboyson | 13:9cd54f7db57a | 27 | |
andrewboyson | 13:9cd54f7db57a | 28 | bool DnsHdrIsReply; |
andrewboyson | 13:9cd54f7db57a | 29 | bool DnsHdrIsAuthoritative; |
andrewboyson | 13:9cd54f7db57a | 30 | bool DnsHdrIsRecursiveQuery; |
andrewboyson | 13:9cd54f7db57a | 31 | |
andrewboyson | 13:9cd54f7db57a | 32 | uint16_t DnsHdrQdcount; |
andrewboyson | 13:9cd54f7db57a | 33 | uint16_t DnsHdrAncount; |
andrewboyson | 13:9cd54f7db57a | 34 | uint16_t DnsHdrNscount; |
andrewboyson | 13:9cd54f7db57a | 35 | uint16_t DnsHdrArcount; |
andrewboyson | 13:9cd54f7db57a | 36 | |
andrewboyson | 13:9cd54f7db57a | 37 | char* DnsHdrPacket; |
andrewboyson | 13:9cd54f7db57a | 38 | char* DnsHdrData; |
andrewboyson | 59:e0e556c8bd46 | 39 | int DnsHdrDataLength; |
andrewboyson | 13:9cd54f7db57a | 40 | |
andrewboyson | 59:e0e556c8bd46 | 41 | void DnsHdrSetup(void* pPacket, int lenPacket) |
andrewboyson | 13:9cd54f7db57a | 42 | { |
andrewboyson | 13:9cd54f7db57a | 43 | DnsHdrPacket = (char*)pPacket; |
andrewboyson | 59:e0e556c8bd46 | 44 | DnsHdrData = DnsHdrPacket + sizeof(header); |
andrewboyson | 59:e0e556c8bd46 | 45 | DnsHdrDataLength = lenPacket - sizeof(header); |
andrewboyson | 13:9cd54f7db57a | 46 | } |
andrewboyson | 13:9cd54f7db57a | 47 | |
andrewboyson | 13:9cd54f7db57a | 48 | void DnsHdrRead() |
andrewboyson | 13:9cd54f7db57a | 49 | { |
andrewboyson | 13:9cd54f7db57a | 50 | struct header* pHeader = (header*)DnsHdrPacket; |
andrewboyson | 13:9cd54f7db57a | 51 | |
andrewboyson | 13:9cd54f7db57a | 52 | DnsHdrId = NetToHost16(pHeader->id); |
andrewboyson | 13:9cd54f7db57a | 53 | |
andrewboyson | 13:9cd54f7db57a | 54 | uint8_t uflags = pHeader->uflags; |
andrewboyson | 13:9cd54f7db57a | 55 | DnsHdrIsReply = uflags & 0x80; |
andrewboyson | 13:9cd54f7db57a | 56 | DnsHdrIsAuthoritative = uflags & 0x04; |
andrewboyson | 33:714a0345e59b | 57 | DnsHdrIsRecursiveQuery = uflags & 0x01; |
andrewboyson | 13:9cd54f7db57a | 58 | |
andrewboyson | 13:9cd54f7db57a | 59 | DnsHdrQdcount = NetToHost16(pHeader->qdcount); |
andrewboyson | 13:9cd54f7db57a | 60 | DnsHdrAncount = NetToHost16(pHeader->ancount); |
andrewboyson | 13:9cd54f7db57a | 61 | DnsHdrNscount = NetToHost16(pHeader->nscount); |
andrewboyson | 13:9cd54f7db57a | 62 | DnsHdrArcount = NetToHost16(pHeader->arcount); |
andrewboyson | 13:9cd54f7db57a | 63 | |
andrewboyson | 13:9cd54f7db57a | 64 | } |
andrewboyson | 13:9cd54f7db57a | 65 | void DnsHdrWrite() |
andrewboyson | 13:9cd54f7db57a | 66 | { |
andrewboyson | 13:9cd54f7db57a | 67 | struct header* pHeader = (header*)DnsHdrPacket; |
andrewboyson | 13:9cd54f7db57a | 68 | |
andrewboyson | 13:9cd54f7db57a | 69 | pHeader->id = NetToHost16(DnsHdrId); |
andrewboyson | 13:9cd54f7db57a | 70 | |
andrewboyson | 13:9cd54f7db57a | 71 | uint8_t uflags = 0; |
andrewboyson | 13:9cd54f7db57a | 72 | uint8_t lflags = 0; |
andrewboyson | 13:9cd54f7db57a | 73 | if (DnsHdrIsReply) uflags |= 0x80; |
andrewboyson | 13:9cd54f7db57a | 74 | if (DnsHdrIsAuthoritative) uflags |= 0x04; |
andrewboyson | 13:9cd54f7db57a | 75 | if (DnsHdrIsRecursiveQuery) uflags |= 0x01; |
andrewboyson | 13:9cd54f7db57a | 76 | pHeader->uflags = uflags; |
andrewboyson | 13:9cd54f7db57a | 77 | pHeader->lflags = lflags; |
andrewboyson | 13:9cd54f7db57a | 78 | |
andrewboyson | 13:9cd54f7db57a | 79 | pHeader->qdcount = NetToHost16(DnsHdrQdcount); |
andrewboyson | 13:9cd54f7db57a | 80 | pHeader->ancount = NetToHost16(DnsHdrAncount); |
andrewboyson | 13:9cd54f7db57a | 81 | pHeader->nscount = NetToHost16(DnsHdrNscount); |
andrewboyson | 13:9cd54f7db57a | 82 | pHeader->arcount = NetToHost16(DnsHdrArcount); |
andrewboyson | 13:9cd54f7db57a | 83 | } |
andrewboyson | 58:d48c899e482f | 84 | static uint16_t decodeUint16(char* p) |
andrewboyson | 58:d48c899e482f | 85 | { |
andrewboyson | 58:d48c899e482f | 86 | uint16_t value = *p++; |
andrewboyson | 58:d48c899e482f | 87 | value <<= 8; value += *p++; |
andrewboyson | 58:d48c899e482f | 88 | return value; |
andrewboyson | 58:d48c899e482f | 89 | } |
andrewboyson | 58:d48c899e482f | 90 | static uint32_t decodeUint32(char* p) |
andrewboyson | 58:d48c899e482f | 91 | { |
andrewboyson | 58:d48c899e482f | 92 | uint32_t value = *p++; |
andrewboyson | 58:d48c899e482f | 93 | value <<= 8; value += *p++; |
andrewboyson | 58:d48c899e482f | 94 | value <<= 8; value += *p++; |
andrewboyson | 58:d48c899e482f | 95 | value <<= 8; value += *p++; |
andrewboyson | 58:d48c899e482f | 96 | return value; |
andrewboyson | 58:d48c899e482f | 97 | } |
andrewboyson | 58:d48c899e482f | 98 | static void logRecordA(int len, char* p) |
andrewboyson | 58:d48c899e482f | 99 | { |
andrewboyson | 58:d48c899e482f | 100 | if (len == 4) Ip4AddressLog(*(uint32_t*)p); |
andrewboyson | 58:d48c899e482f | 101 | else LogF("expected 4 bytes but had %d", len); |
andrewboyson | 58:d48c899e482f | 102 | } |
andrewboyson | 58:d48c899e482f | 103 | static void logRecordAAAA(int len, char* p) |
andrewboyson | 58:d48c899e482f | 104 | { |
andrewboyson | 58:d48c899e482f | 105 | if (len == 16) Ip6AddressLog(p); |
andrewboyson | 58:d48c899e482f | 106 | else LogF("expected 16 bytes but had %d", len); |
andrewboyson | 58:d48c899e482f | 107 | } |
andrewboyson | 58:d48c899e482f | 108 | static void logRecordPTR(int len, char* p) |
andrewboyson | 58:d48c899e482f | 109 | { |
andrewboyson | 58:d48c899e482f | 110 | if (len <= DNS_MAX_LABEL_LENGTH) DnsNameLogPtr(p); |
andrewboyson | 58:d48c899e482f | 111 | else LogF("length %d is greater than max DNS label length of %d\r\n", len, DNS_MAX_LABEL_LENGTH); |
andrewboyson | 58:d48c899e482f | 112 | } |
andrewboyson | 58:d48c899e482f | 113 | static void logRecordSRV(int len, char* p) |
andrewboyson | 58:d48c899e482f | 114 | { |
andrewboyson | 58:d48c899e482f | 115 | LogF("pri=%d " , decodeUint16(p)); p += 2; |
andrewboyson | 58:d48c899e482f | 116 | LogF("wei=%d " , decodeUint16(p)); p += 2; |
andrewboyson | 58:d48c899e482f | 117 | LogF("port=%d ", decodeUint16(p)); p += 2; |
andrewboyson | 58:d48c899e482f | 118 | DnsNameLogPtr(p); |
andrewboyson | 58:d48c899e482f | 119 | } |
andrewboyson | 58:d48c899e482f | 120 | static void logRecordTXT(int len, char* p) |
andrewboyson | 58:d48c899e482f | 121 | { |
andrewboyson | 58:d48c899e482f | 122 | char* pEnd = p + len; |
andrewboyson | 58:d48c899e482f | 123 | while (p < pEnd) |
andrewboyson | 58:d48c899e482f | 124 | { |
andrewboyson | 58:d48c899e482f | 125 | Log("\r\n "); |
andrewboyson | 58:d48c899e482f | 126 | int fieldLen = *p++; |
andrewboyson | 58:d48c899e482f | 127 | for (int i = 0; i < fieldLen; i++) LogPush(*p++); |
andrewboyson | 58:d48c899e482f | 128 | } |
andrewboyson | 58:d48c899e482f | 129 | } |
andrewboyson | 37:793b39683406 | 130 | static void logContent() |
andrewboyson | 37:793b39683406 | 131 | { |
andrewboyson | 58:d48c899e482f | 132 | char* p = DnsHdrData; |
andrewboyson | 37:793b39683406 | 133 | |
andrewboyson | 37:793b39683406 | 134 | //Get the questions |
andrewboyson | 37:793b39683406 | 135 | for (int q = 0; q < DnsHdrQdcount; q++) |
andrewboyson | 37:793b39683406 | 136 | { |
andrewboyson | 59:e0e556c8bd46 | 137 | if (p >= DnsHdrData + DnsHdrDataLength) |
andrewboyson | 37:793b39683406 | 138 | { |
andrewboyson | 58:d48c899e482f | 139 | Log(" Questions have overrun the buffer\r\n"); |
andrewboyson | 37:793b39683406 | 140 | return; |
andrewboyson | 37:793b39683406 | 141 | } |
andrewboyson | 58:d48c899e482f | 142 | char* pEncodedName = p; |
andrewboyson | 37:793b39683406 | 143 | int nameLength = DnsNameLength(p); |
andrewboyson | 58:d48c899e482f | 144 | if (!nameLength) { LogTimeF(" Questions namelength is zero\r\n"); return; } |
andrewboyson | 37:793b39683406 | 145 | p += nameLength; //Skip past the name |
andrewboyson | 37:793b39683406 | 146 | p++ ; //skip the first byte of the type |
andrewboyson | 37:793b39683406 | 147 | char recordType = *p++; //read the record type |
andrewboyson | 37:793b39683406 | 148 | p += 2; //skip the class |
andrewboyson | 37:793b39683406 | 149 | |
andrewboyson | 47:73af5c0b0dc2 | 150 | LogF(" Query "); |
andrewboyson | 47:73af5c0b0dc2 | 151 | DnsRecordTypeLog(recordType); |
andrewboyson | 47:73af5c0b0dc2 | 152 | Log(" type record of "); |
andrewboyson | 58:d48c899e482f | 153 | DnsNameLogPtr(pEncodedName); |
andrewboyson | 47:73af5c0b0dc2 | 154 | Log("\r\n"); |
andrewboyson | 37:793b39683406 | 155 | } |
andrewboyson | 37:793b39683406 | 156 | |
andrewboyson | 37:793b39683406 | 157 | //Get the answers |
andrewboyson | 37:793b39683406 | 158 | for (int a = 0; a < DnsHdrAncount; a++) |
andrewboyson | 37:793b39683406 | 159 | { |
andrewboyson | 59:e0e556c8bd46 | 160 | if (p >= DnsHdrData + DnsHdrDataLength) { Log(" Answers have overrun the buffer\r\n"); return; } |
andrewboyson | 37:793b39683406 | 161 | |
andrewboyson | 58:d48c899e482f | 162 | char* pEncodedName = p; |
andrewboyson | 37:793b39683406 | 163 | int nameLength = DnsNameLength(p); |
andrewboyson | 43:bc028d5a6424 | 164 | if (!nameLength) { Log(" Answer name length is zero\r\n"); return; } |
andrewboyson | 37:793b39683406 | 165 | p += nameLength; //Skip past the name |
andrewboyson | 37:793b39683406 | 166 | |
andrewboyson | 37:793b39683406 | 167 | p++; //Skip the high byte of the record type |
andrewboyson | 37:793b39683406 | 168 | int recordType = *p++; //Record type |
andrewboyson | 37:793b39683406 | 169 | |
andrewboyson | 37:793b39683406 | 170 | p++; //Skip the high byte of the class type |
andrewboyson | 37:793b39683406 | 171 | int classType = *p++; //Class type |
andrewboyson | 37:793b39683406 | 172 | |
andrewboyson | 58:d48c899e482f | 173 | int ttl = decodeUint32(p); p += 4; //32bit TTL |
andrewboyson | 37:793b39683406 | 174 | |
andrewboyson | 58:d48c899e482f | 175 | int len = decodeUint16(p); p += 2; //16bit length |
andrewboyson | 37:793b39683406 | 176 | |
andrewboyson | 43:bc028d5a6424 | 177 | Log(" Answer "); |
andrewboyson | 47:73af5c0b0dc2 | 178 | DnsRecordTypeLog(recordType); |
andrewboyson | 43:bc028d5a6424 | 179 | Log(" type record of "); |
andrewboyson | 58:d48c899e482f | 180 | DnsNameLogPtr(pEncodedName); |
andrewboyson | 43:bc028d5a6424 | 181 | Log(" ==> "); |
andrewboyson | 37:793b39683406 | 182 | |
andrewboyson | 37:793b39683406 | 183 | switch (recordType) //Log the payload if its type is known |
andrewboyson | 37:793b39683406 | 184 | { |
andrewboyson | 58:d48c899e482f | 185 | case DNS_RECORD_A: logRecordA (len, p); break; |
andrewboyson | 58:d48c899e482f | 186 | case DNS_RECORD_AAAA: logRecordAAAA(len, p); break; |
andrewboyson | 58:d48c899e482f | 187 | case DNS_RECORD_PTR: logRecordPTR (len, p); break; |
andrewboyson | 58:d48c899e482f | 188 | case DNS_RECORD_SRV: logRecordSRV (len, p); break; |
andrewboyson | 58:d48c899e482f | 189 | case DNS_RECORD_TXT: logRecordTXT (len, p); break; |
andrewboyson | 58:d48c899e482f | 190 | default: LogF("%d characters", len); break; |
andrewboyson | 37:793b39683406 | 191 | } |
andrewboyson | 43:bc028d5a6424 | 192 | Log("\r\n"); |
andrewboyson | 37:793b39683406 | 193 | p += len; //Adjust the pointer to the next character after the payload |
andrewboyson | 37:793b39683406 | 194 | } |
andrewboyson | 37:793b39683406 | 195 | } |
andrewboyson | 37:793b39683406 | 196 | |
andrewboyson | 37:793b39683406 | 197 | void DnsHdrLog(int protocol) |
andrewboyson | 13:9cd54f7db57a | 198 | { |
andrewboyson | 43:bc028d5a6424 | 199 | if (NetTraceVerbose) |
andrewboyson | 15:6ca6778168b1 | 200 | { |
andrewboyson | 47:73af5c0b0dc2 | 201 | DnsProtocolLog(protocol); |
andrewboyson | 47:73af5c0b0dc2 | 202 | Log(" header\r\n"); |
andrewboyson | 43:bc028d5a6424 | 203 | LogF(" Ident %hd\r\n", DnsHdrId); |
andrewboyson | 43:bc028d5a6424 | 204 | if (DnsHdrIsReply) |
andrewboyson | 43:bc028d5a6424 | 205 | { |
andrewboyson | 43:bc028d5a6424 | 206 | if (DnsHdrIsAuthoritative) LogF(" Authoritative reply\r\n"); |
andrewboyson | 43:bc028d5a6424 | 207 | else LogF(" Non authoritative reply\r\n"); |
andrewboyson | 43:bc028d5a6424 | 208 | } |
andrewboyson | 43:bc028d5a6424 | 209 | else |
andrewboyson | 43:bc028d5a6424 | 210 | { |
andrewboyson | 43:bc028d5a6424 | 211 | if (DnsHdrIsRecursiveQuery) LogF(" Recursive query\r\n"); |
andrewboyson | 43:bc028d5a6424 | 212 | else LogF(" Non recursive query\r\n"); |
andrewboyson | 43:bc028d5a6424 | 213 | } |
andrewboyson | 43:bc028d5a6424 | 214 | LogF(" qd, an, ns, ar %hu, %hu, %hu, %hu\r\n", DnsHdrQdcount, DnsHdrAncount, DnsHdrNscount, DnsHdrArcount); |
andrewboyson | 15:6ca6778168b1 | 215 | } |
andrewboyson | 15:6ca6778168b1 | 216 | else |
andrewboyson | 15:6ca6778168b1 | 217 | { |
andrewboyson | 47:73af5c0b0dc2 | 218 | DnsProtocolLog(protocol); |
andrewboyson | 47:73af5c0b0dc2 | 219 | LogF(" header qd, an, ns, ar %hu, %hu, %hu, %hu\r\n", DnsHdrQdcount, DnsHdrAncount, DnsHdrNscount, DnsHdrArcount); |
andrewboyson | 15:6ca6778168b1 | 220 | } |
andrewboyson | 37:793b39683406 | 221 | logContent(); |
andrewboyson | 13:9cd54f7db57a | 222 | } |
andrewboyson | 13:9cd54f7db57a | 223 |