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/dns.cpp@37:793b39683406, 2017-10-04 (annotated)

Committer:
andrewboyson
Date:
Wed Oct 04 07:51:02 2017 +0000
Revision:
37:793b39683406
Parent:
33:714a0345e59b
Child:
41:db727df5f98b
Added trace back and trace forward to log messages

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 13:9cd54f7db57a 1 #include "dns.h"
andrewboyson 13:9cd54f7db57a 2 #include "dnshdr.h"
andrewboyson 13:9cd54f7db57a 3 #include "dnsquery.h"
andrewboyson 13:9cd54f7db57a 4 #include "dnsreply.h"
andrewboyson 13:9cd54f7db57a 5 #include "dnsserver.h"
andrewboyson 13:9cd54f7db57a 6 #include "io.h"
andrewboyson 32:679654f2d023 7 #include "log.h"
andrewboyson 32:679654f2d023 8 #include "dhcp.h"
andrewboyson 13:9cd54f7db57a 9
andrewboyson 13:9cd54f7db57a 10 void DnsProtocolToString(uint8_t protocol, int size, char* text)
andrewboyson 13:9cd54f7db57a 11 {
andrewboyson 13:9cd54f7db57a 12 switch (protocol)
andrewboyson 13:9cd54f7db57a 13 {
andrewboyson 13:9cd54f7db57a 14 case DNS_PROTOCOL_UDNS: strncpy (text, "DNS", size); break;
andrewboyson 13:9cd54f7db57a 15 case DNS_PROTOCOL_MDNS: strncpy (text, "MDNS", size); break;
andrewboyson 13:9cd54f7db57a 16 case DNS_PROTOCOL_LLMNR: strncpy (text, "LLMNR", size); break;
andrewboyson 13:9cd54f7db57a 17 default: snprintf(text, size, "%d", protocol); break;
andrewboyson 13:9cd54f7db57a 18 }
andrewboyson 13:9cd54f7db57a 19 }
andrewboyson 13:9cd54f7db57a 20
andrewboyson 13:9cd54f7db57a 21 void DnsRecordTypeToString(uint8_t recordtype, int size, char* text)
andrewboyson 13:9cd54f7db57a 22 {
andrewboyson 13:9cd54f7db57a 23 switch (recordtype)
andrewboyson 13:9cd54f7db57a 24 {
andrewboyson 13:9cd54f7db57a 25 case DNS_RECORD_A: strncpy (text, "A", size); break;
andrewboyson 13:9cd54f7db57a 26 case DNS_RECORD_AAAA: strncpy (text, "AAAA", size); break;
andrewboyson 13:9cd54f7db57a 27 case DNS_RECORD_PTR: strncpy (text, "PTR", size); break;
andrewboyson 15:6ca6778168b1 28 case DNS_RECORD_TXT: strncpy (text, "TXT", size); break;
andrewboyson 15:6ca6778168b1 29 case DNS_RECORD_SRV: strncpy (text, "SRV", size); break;
andrewboyson 13:9cd54f7db57a 30 default: snprintf(text, size, "%d", recordtype); break;
andrewboyson 13:9cd54f7db57a 31 }
andrewboyson 13:9cd54f7db57a 32 }
andrewboyson 32:679654f2d023 33 int DnsGetNextProtocol(int protocol)
andrewboyson 32:679654f2d023 34 {
andrewboyson 32:679654f2d023 35 switch(protocol)
andrewboyson 32:679654f2d023 36 {
andrewboyson 32:679654f2d023 37 case DNS_PROTOCOL_NONE: return DNS_PROTOCOL_UDNS;
andrewboyson 32:679654f2d023 38 case DNS_PROTOCOL_UDNS: return DNS_PROTOCOL_MDNS;
andrewboyson 32:679654f2d023 39 case DNS_PROTOCOL_MDNS: return DNS_PROTOCOL_LLMNR;
andrewboyson 32:679654f2d023 40 case DNS_PROTOCOL_LLMNR: return DNS_PROTOCOL_NONE;
andrewboyson 32:679654f2d023 41 default: LogTimeF("DNS invalid protocol %d\r\n", protocol); return DNS_PROTOCOL_NONE;
andrewboyson 32:679654f2d023 42 }
andrewboyson 32:679654f2d023 43 }
andrewboyson 33:714a0345e59b 44 bool DnsHostNamesEquate(char* pA, char* pB)
andrewboyson 33:714a0345e59b 45 {
andrewboyson 33:714a0345e59b 46 while(true)
andrewboyson 33:714a0345e59b 47 {
andrewboyson 33:714a0345e59b 48 char a = *pA++;
andrewboyson 33:714a0345e59b 49 char b = *pB++;
andrewboyson 33:714a0345e59b 50 if (a >= 'A' && a <= 'Z') a |= 0x20; //Make lower case
andrewboyson 33:714a0345e59b 51 if (b >= 'A' && b <= 'Z') b |= 0x20; //Make lower case
andrewboyson 33:714a0345e59b 52 if (a != b) return false; //If different then stop and return the fact
andrewboyson 33:714a0345e59b 53 if (!a) break; //No need to check 'b' too as it will necessarily be equal to 'a' at this point.
andrewboyson 33:714a0345e59b 54 }
andrewboyson 33:714a0345e59b 55 return true; //If we get here the strings must equate.
andrewboyson 33:714a0345e59b 56 }
andrewboyson 33:714a0345e59b 57
andrewboyson 32:679654f2d023 58 int DnsMakeFullNameFromName(int protocol, char* p, int size, char* result)
andrewboyson 32:679654f2d023 59 {
andrewboyson 32:679654f2d023 60 int i = 0;
andrewboyson 32:679654f2d023 61 char c;
andrewboyson 32:679654f2d023 62
andrewboyson 32:679654f2d023 63 while (i < size - 1)
andrewboyson 32:679654f2d023 64 {
andrewboyson 32:679654f2d023 65 c = *p++;
andrewboyson 32:679654f2d023 66 if (!c) break;
andrewboyson 32:679654f2d023 67 *result++ = c;
andrewboyson 32:679654f2d023 68 i++;
andrewboyson 32:679654f2d023 69 }
andrewboyson 32:679654f2d023 70 if (protocol == DNS_PROTOCOL_MDNS)
andrewboyson 32:679654f2d023 71 {
andrewboyson 32:679654f2d023 72 p = ".local";
andrewboyson 32:679654f2d023 73 while (i < size - 1)
andrewboyson 32:679654f2d023 74 {
andrewboyson 32:679654f2d023 75 c = *p++;
andrewboyson 32:679654f2d023 76 if (!c) break;
andrewboyson 32:679654f2d023 77 *result++ = c;
andrewboyson 32:679654f2d023 78 i++;
andrewboyson 32:679654f2d023 79 }
andrewboyson 32:679654f2d023 80 }
andrewboyson 32:679654f2d023 81 if (protocol == DNS_PROTOCOL_UDNS && DhcpDomainName[0]) //Shouldn't do this in IPv6 as DHCP is IPv4 only
andrewboyson 32:679654f2d023 82 {
andrewboyson 32:679654f2d023 83 if (i < size - 1)
andrewboyson 32:679654f2d023 84 {
andrewboyson 32:679654f2d023 85 *result++ = '.';
andrewboyson 32:679654f2d023 86 i++;
andrewboyson 32:679654f2d023 87 }
andrewboyson 32:679654f2d023 88 p = DhcpDomainName;
andrewboyson 32:679654f2d023 89 while (i < size - 1)
andrewboyson 32:679654f2d023 90 {
andrewboyson 32:679654f2d023 91 c = *p++;
andrewboyson 32:679654f2d023 92 if (!c) break;
andrewboyson 32:679654f2d023 93 *result++ = c;
andrewboyson 32:679654f2d023 94 i++;
andrewboyson 32:679654f2d023 95 }
andrewboyson 32:679654f2d023 96 }
andrewboyson 32:679654f2d023 97 *result = 0; //Terminate the resulting string
andrewboyson 32:679654f2d023 98 return i;
andrewboyson 32:679654f2d023 99 }
andrewboyson 32:679654f2d023 100 int DnsStripNameFromFullName(int protocol, char* p, int size, char* result)
andrewboyson 32:679654f2d023 101 {
andrewboyson 32:679654f2d023 102 int i = 0;
andrewboyson 32:679654f2d023 103 char c;
andrewboyson 32:679654f2d023 104
andrewboyson 32:679654f2d023 105 while (i < size - 1)
andrewboyson 32:679654f2d023 106 {
andrewboyson 32:679654f2d023 107 c = *p++;
andrewboyson 32:679654f2d023 108 if (c == 0) break; //End of the fqdn so stop
andrewboyson 32:679654f2d023 109 if (c == '.')
andrewboyson 32:679654f2d023 110 {
andrewboyson 32:679654f2d023 111 if (protocol == DNS_PROTOCOL_UDNS)
andrewboyson 32:679654f2d023 112 {
andrewboyson 32:679654f2d023 113 if (strcmp(p, DhcpDomainName) == 0) break; //Strip the domain from a UDNS fqdn if, and only if, it matches the domain given in DHCP. IPv4 only.
andrewboyson 32:679654f2d023 114 }
andrewboyson 32:679654f2d023 115 else
andrewboyson 32:679654f2d023 116 {
andrewboyson 32:679654f2d023 117 break; //Strip the domain from an LLMNR (there shouldn't be one) or MDNS (it should always be '.local') fqdn
andrewboyson 32:679654f2d023 118 }
andrewboyson 32:679654f2d023 119 }
andrewboyson 32:679654f2d023 120 *result++ = c;
andrewboyson 32:679654f2d023 121 i++;
andrewboyson 32:679654f2d023 122 }
andrewboyson 32:679654f2d023 123 *result = 0; //Terminate the copied string
andrewboyson 32:679654f2d023 124 return i;
andrewboyson 32:679654f2d023 125 }
andrewboyson 13:9cd54f7db57a 126
andrewboyson 13:9cd54f7db57a 127 void DnsTick()
andrewboyson 13:9cd54f7db57a 128 {
andrewboyson 13:9cd54f7db57a 129 DnsQueryTick();
andrewboyson 13:9cd54f7db57a 130 }
andrewboyson 13:9cd54f7db57a 131
andrewboyson 37:793b39683406 132 int DnsHandlePacketReceived(void (*traceback)(void), int dnsProtocol, int* pSize, void* pPacket)
andrewboyson 13:9cd54f7db57a 133 {
andrewboyson 13:9cd54f7db57a 134 DnsHdrSetup(pPacket);
andrewboyson 13:9cd54f7db57a 135 DnsHdrRead();
andrewboyson 13:9cd54f7db57a 136 int action;
andrewboyson 13:9cd54f7db57a 137 if (DnsHdrIsReply)
andrewboyson 13:9cd54f7db57a 138 {
andrewboyson 37:793b39683406 139 action = DnsReplyHandle(traceback, dnsProtocol, pSize);
andrewboyson 13:9cd54f7db57a 140 }
andrewboyson 13:9cd54f7db57a 141 else
andrewboyson 13:9cd54f7db57a 142 {
andrewboyson 37:793b39683406 143 action = DnsServerHandleQuery(traceback, dnsProtocol, pSize);
andrewboyson 13:9cd54f7db57a 144 }
andrewboyson 13:9cd54f7db57a 145 return action;
andrewboyson 13:9cd54f7db57a 146 }
andrewboyson 13:9cd54f7db57a 147
andrewboyson 13:9cd54f7db57a 148 int DnsPollForPacketToSend(void* pPacket, int* pSize)
andrewboyson 13:9cd54f7db57a 149 {
andrewboyson 13:9cd54f7db57a 150 DnsHdrSetup(pPacket);
andrewboyson 13:9cd54f7db57a 151 return DnsQueryPoll(pSize);
andrewboyson 13:9cd54f7db57a 152 }