Andrew Boyson / net

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependents:   oldheating gps motorhome heating

udp/dns/dnsserver.cpp@22:914b970356f0, 2017-07-03 (annotated)

Committer:
andrewboyson
Date:
Mon Jul 03 14:29:07 2017 +0000
Revision:
22:914b970356f0
Parent:
13:9cd54f7db57a
Child:
32:679654f2d023
Corrected NTP client function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 13:9cd54f7db57a 1 #include "mbed.h"
andrewboyson 13:9cd54f7db57a 2 #include "dnshdr.h"
andrewboyson 13:9cd54f7db57a 3 #include "dnsname.h"
andrewboyson 13:9cd54f7db57a 4 #include "net.h"
andrewboyson 13:9cd54f7db57a 5 #include "dns.h"
andrewboyson 13:9cd54f7db57a 6 #include "log.h"
andrewboyson 13:9cd54f7db57a 7 #include "dhcp.h"
andrewboyson 13:9cd54f7db57a 8 #include "slaac.h"
andrewboyson 13:9cd54f7db57a 9 #include "io.h"
andrewboyson 13:9cd54f7db57a 10
andrewboyson 13:9cd54f7db57a 11 #define DEBUG false
andrewboyson 13:9cd54f7db57a 12
andrewboyson 13:9cd54f7db57a 13 int DnsServerHandleQuery(int dnsProtocol, int *pSize) //Received an mdns or llmnr query on port 5353 or 5355
andrewboyson 13:9cd54f7db57a 14 {
andrewboyson 13:9cd54f7db57a 15 if (DEBUG) DnsHdrLog("server received query", dnsProtocol);
andrewboyson 13:9cd54f7db57a 16
andrewboyson 22:914b970356f0 17 if ( *pSize > 512)
andrewboyson 22:914b970356f0 18 {
andrewboyson 22:914b970356f0 19 if (DEBUG) LogTimeF("DnsServerHandleQuery length %d too long\r\n", *pSize);
andrewboyson 22:914b970356f0 20 return DO_NOTHING;
andrewboyson 22:914b970356f0 21 }
andrewboyson 22:914b970356f0 22 if (DnsHdrQdcount > 4)
andrewboyson 22:914b970356f0 23 {
andrewboyson 22:914b970356f0 24 if (DEBUG) LogTimeF("DnsServerHandleQuery too many queries %d\r\n", *pSize);
andrewboyson 22:914b970356f0 25 return DO_NOTHING;
andrewboyson 22:914b970356f0 26 }
andrewboyson 13:9cd54f7db57a 27
andrewboyson 13:9cd54f7db57a 28 char *p = DnsHdrData;
andrewboyson 13:9cd54f7db57a 29
andrewboyson 13:9cd54f7db57a 30 char iEncodedName;
andrewboyson 13:9cd54f7db57a 31 bool isMe = false;
andrewboyson 13:9cd54f7db57a 32 int types[4];
andrewboyson 13:9cd54f7db57a 33 bool mdnsUnicastReply = false;
andrewboyson 13:9cd54f7db57a 34
andrewboyson 13:9cd54f7db57a 35 //Get the questions
andrewboyson 13:9cd54f7db57a 36 DnsHdrAncount = 0;
andrewboyson 13:9cd54f7db57a 37 for (int q = 0; q < DnsHdrQdcount; q++)
andrewboyson 13:9cd54f7db57a 38 {
andrewboyson 13:9cd54f7db57a 39 iEncodedName = DnsNameIndexFromPointer(p);
andrewboyson 13:9cd54f7db57a 40 int nameLength = DnsNameLength(p);
andrewboyson 13:9cd54f7db57a 41 if (!nameLength) return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 42 if (!q) isMe = DnsNameCompare(p, NetName); //get the name: rtc.local; 3.1.168.192.inaddr.arpa; etc
andrewboyson 13:9cd54f7db57a 43 p += nameLength; //Skip past the name
andrewboyson 13:9cd54f7db57a 44 p++ ; //skip the first byte of the type
andrewboyson 13:9cd54f7db57a 45 char recordType = *p++; //read the record type
andrewboyson 13:9cd54f7db57a 46 if (*p++ & 0x80) mdnsUnicastReply = true; //Check the 15th bit (UNICAST-RESPONSE)
andrewboyson 13:9cd54f7db57a 47 p += 1; //skip the class
andrewboyson 13:9cd54f7db57a 48
andrewboyson 13:9cd54f7db57a 49 types[q] = recordType;
andrewboyson 13:9cd54f7db57a 50
andrewboyson 13:9cd54f7db57a 51 if (DEBUG)
andrewboyson 13:9cd54f7db57a 52 {
andrewboyson 13:9cd54f7db57a 53 switch (recordType)
andrewboyson 13:9cd54f7db57a 54 {
andrewboyson 13:9cd54f7db57a 55 case DNS_RECORD_A: LogF(" for IP4 address\r\n"); break;
andrewboyson 13:9cd54f7db57a 56 case DNS_RECORD_PTR: LogF(" for name\r\n"); break;
andrewboyson 13:9cd54f7db57a 57 case DNS_RECORD_AAAA: LogF(" for IP6 address\r\n"); break;
andrewboyson 13:9cd54f7db57a 58 default: LogF(" for unrecognised record type %d\r\n", recordType); break;
andrewboyson 13:9cd54f7db57a 59 }
andrewboyson 13:9cd54f7db57a 60 char text[256];
andrewboyson 13:9cd54f7db57a 61 DnsNameDecode(iEncodedName, sizeof(text), text);
andrewboyson 13:9cd54f7db57a 62 LogF(" Name %s\r\n", text);
andrewboyson 13:9cd54f7db57a 63 }
andrewboyson 13:9cd54f7db57a 64 }
andrewboyson 13:9cd54f7db57a 65 if (!isMe) return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 66
andrewboyson 13:9cd54f7db57a 67 //Respond to the questions
andrewboyson 13:9cd54f7db57a 68 for (int q = 0; q < DnsHdrQdcount; q++)
andrewboyson 13:9cd54f7db57a 69 {
andrewboyson 13:9cd54f7db57a 70 switch (types[q])
andrewboyson 13:9cd54f7db57a 71 {
andrewboyson 13:9cd54f7db57a 72 case DNS_RECORD_A:
andrewboyson 13:9cd54f7db57a 73 if (p - DnsHdrPacket > 500)
andrewboyson 13:9cd54f7db57a 74 {
andrewboyson 13:9cd54f7db57a 75 LogTimeF("DNS server ip4 query reply is getting too big\r\n");
andrewboyson 13:9cd54f7db57a 76 return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 77 }
andrewboyson 13:9cd54f7db57a 78 DnsHdrAncount++;
andrewboyson 13:9cd54f7db57a 79 //Name
andrewboyson 13:9cd54f7db57a 80 DnsNameEncode(NetName, &p);
andrewboyson 13:9cd54f7db57a 81
andrewboyson 13:9cd54f7db57a 82 //16 bit Type
andrewboyson 13:9cd54f7db57a 83 *p++ = 0; //MSB type
andrewboyson 13:9cd54f7db57a 84 *p++ = DNS_RECORD_A;
andrewboyson 13:9cd54f7db57a 85
andrewboyson 13:9cd54f7db57a 86 //Class
andrewboyson 13:9cd54f7db57a 87 *p++ = dnsProtocol == DNS_PROTOCOL_MDNS ? 0x80 : 0; //Set the 15th bit (CACHE_FLUSH) to 1 if MDNS
andrewboyson 13:9cd54f7db57a 88 *p++ = 1; //QCLASS_IN = 1 - internet
andrewboyson 13:9cd54f7db57a 89
andrewboyson 13:9cd54f7db57a 90 //32 bit TTL seconds
andrewboyson 13:9cd54f7db57a 91 *p++ = 0;
andrewboyson 13:9cd54f7db57a 92 *p++ = 0;
andrewboyson 13:9cd54f7db57a 93 *p++ = 4; //1024 seconds
andrewboyson 13:9cd54f7db57a 94 *p++ = 0;
andrewboyson 13:9cd54f7db57a 95
andrewboyson 13:9cd54f7db57a 96 //16bit length in bytes
andrewboyson 13:9cd54f7db57a 97 *p++ = 0;
andrewboyson 13:9cd54f7db57a 98 *p++ = 4;
andrewboyson 13:9cd54f7db57a 99
andrewboyson 13:9cd54f7db57a 100 //Value
andrewboyson 13:9cd54f7db57a 101 memcpy(p, &DhcpLocalIp, 4);
andrewboyson 13:9cd54f7db57a 102 p += 4;
andrewboyson 13:9cd54f7db57a 103 break;
andrewboyson 13:9cd54f7db57a 104
andrewboyson 13:9cd54f7db57a 105 case DNS_RECORD_AAAA:
andrewboyson 13:9cd54f7db57a 106 if (p - DnsHdrPacket > 500)
andrewboyson 13:9cd54f7db57a 107 {
andrewboyson 13:9cd54f7db57a 108 LogTimeF("DNS server Ip6 query reply is getting too big\r\n");
andrewboyson 13:9cd54f7db57a 109 return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 110 }
andrewboyson 13:9cd54f7db57a 111 DnsHdrAncount++;
andrewboyson 13:9cd54f7db57a 112 //Name
andrewboyson 13:9cd54f7db57a 113 DnsNameEncode(NetName, &p);
andrewboyson 13:9cd54f7db57a 114
andrewboyson 13:9cd54f7db57a 115 //16 bit Type
andrewboyson 13:9cd54f7db57a 116 *p++ = 0; //MSB type
andrewboyson 13:9cd54f7db57a 117 *p++ = DNS_RECORD_AAAA;
andrewboyson 13:9cd54f7db57a 118
andrewboyson 13:9cd54f7db57a 119 //Class
andrewboyson 13:9cd54f7db57a 120 *p++ = dnsProtocol == DNS_PROTOCOL_MDNS ? 0x80 : 0; //Set the 15th bit (CACHE_FLUSH) to 1 if MDNS
andrewboyson 13:9cd54f7db57a 121 *p++ = 1; //QCLASS_IN = 1 - internet
andrewboyson 13:9cd54f7db57a 122
andrewboyson 13:9cd54f7db57a 123 //32 bit TTL seconds
andrewboyson 13:9cd54f7db57a 124 *p++ = 0;
andrewboyson 13:9cd54f7db57a 125 *p++ = 0;
andrewboyson 13:9cd54f7db57a 126 *p++ = 4; //1024 seconds
andrewboyson 13:9cd54f7db57a 127 *p++ = 0;
andrewboyson 13:9cd54f7db57a 128
andrewboyson 13:9cd54f7db57a 129 //16bit length in bytes
andrewboyson 13:9cd54f7db57a 130 *p++ = 0;
andrewboyson 13:9cd54f7db57a 131 *p++ = 16;
andrewboyson 13:9cd54f7db57a 132
andrewboyson 13:9cd54f7db57a 133 //Value
andrewboyson 13:9cd54f7db57a 134 memcpy(p, SlaacLinkLocalIp, 16);
andrewboyson 13:9cd54f7db57a 135 p += 16;
andrewboyson 13:9cd54f7db57a 136 break;
andrewboyson 13:9cd54f7db57a 137 }
andrewboyson 13:9cd54f7db57a 138 }
andrewboyson 13:9cd54f7db57a 139 if (!DnsHdrAncount) return DO_NOTHING;
andrewboyson 13:9cd54f7db57a 140
andrewboyson 13:9cd54f7db57a 141 DnsHdrIsReply = true;
andrewboyson 13:9cd54f7db57a 142 DnsHdrIsAuthoritative = true;
andrewboyson 13:9cd54f7db57a 143 DnsHdrWrite();
andrewboyson 13:9cd54f7db57a 144
andrewboyson 13:9cd54f7db57a 145 *pSize = p - DnsHdrPacket;
andrewboyson 13:9cd54f7db57a 146
andrewboyson 13:9cd54f7db57a 147 if (DEBUG) DnsHdrLog("server sending reply", dnsProtocol);
andrewboyson 13:9cd54f7db57a 148
andrewboyson 13:9cd54f7db57a 149 if (dnsProtocol == DNS_PROTOCOL_MDNS && !mdnsUnicastReply) return MULTICAST_MDNS;
andrewboyson 13:9cd54f7db57a 150 return UNICAST;
andrewboyson 13:9cd54f7db57a 151 }