Andrew Boyson / net

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/dnslabel.c@200:5acbc41bf469, 2021-05-20 (annotated)

Committer:
andrewboyson
Date:
Thu May 20 14:32:52 2021 +0000
Revision:
200:5acbc41bf469
Parent:
183:ee809769bf89 
Increased number of arp entries from 20 to 30 to accommodate the number of WIZ devices plus a few incoming port 80 calls from the internet.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
andrewboyson 128:79052cb4a41c 1 #include <stdbool.h>
andrewboyson 128:79052cb4a41c 2 #include <string.h>
andrewboyson 128:79052cb4a41c 3
andrewboyson 128:79052cb4a41c 4 #include "dns.h"
andrewboyson 128:79052cb4a41c 5 #include "dnslabel.h"
andrewboyson 128:79052cb4a41c 6 #include "dhcp.h"
andrewboyson 128:79052cb4a41c 7
andrewboyson 183:ee809769bf89 8 bool DnsLabelIsExternal(char* p)
andrewboyson 183:ee809769bf89 9 {
andrewboyson 183:ee809769bf89 10 while (true)
andrewboyson 183:ee809769bf89 11 {
andrewboyson 183:ee809769bf89 12 if (*p == '\0') return false;
andrewboyson 183:ee809769bf89 13 if (*p == '.') return true;
andrewboyson 183:ee809769bf89 14 p++;
andrewboyson 183:ee809769bf89 15 }
andrewboyson 183:ee809769bf89 16 }
andrewboyson 183:ee809769bf89 17
andrewboyson 128:79052cb4a41c 18 void DnsLabelCopy(char* dst, char* src)
andrewboyson 128:79052cb4a41c 19 {
andrewboyson 128:79052cb4a41c 20 strncpy(dst, src, DNS_MAX_LABEL_LENGTH); //Copies up to 63 bytes
andrewboyson 128:79052cb4a41c 21 dst[DNS_MAX_LABEL_LENGTH] = 0; //dst[63] is the 64th position from 0..63 is set to null. All labels must be declared as a size of 64
andrewboyson 128:79052cb4a41c 22 }
andrewboyson 128:79052cb4a41c 23
andrewboyson 128:79052cb4a41c 24 bool DnsLabelIsSame(char* pA, char* pB)
andrewboyson 128:79052cb4a41c 25 {
andrewboyson 128:79052cb4a41c 26 while(true)
andrewboyson 128:79052cb4a41c 27 {
andrewboyson 128:79052cb4a41c 28 char a = *pA++;
andrewboyson 128:79052cb4a41c 29 char b = *pB++;
andrewboyson 128:79052cb4a41c 30 if (a >= 'A' && a <= 'Z') a |= 0x20; //Make lower case
andrewboyson 128:79052cb4a41c 31 if (b >= 'A' && b <= 'Z') b |= 0x20; //Make lower case
andrewboyson 128:79052cb4a41c 32 if (a != b) return false; //If different then stop and return the fact
andrewboyson 128:79052cb4a41c 33 if (!a) break; //No need to check 'b' too as it will necessarily be equal to 'a' at this point.
andrewboyson 128:79052cb4a41c 34 }
andrewboyson 128:79052cb4a41c 35 return true; //If we get here the strings must equate.
andrewboyson 128:79052cb4a41c 36 }
andrewboyson 128:79052cb4a41c 37
andrewboyson 128:79052cb4a41c 38 int DnsLabelMakeFullNameFromName(int protocol, const char* p, int size, char* result)
andrewboyson 128:79052cb4a41c 39 {
andrewboyson 128:79052cb4a41c 40 int i = 0;
andrewboyson 128:79052cb4a41c 41 char c;
andrewboyson 182:ff48c6ea91c1 42 bool isExternal = false;
andrewboyson 128:79052cb4a41c 43
andrewboyson 128:79052cb4a41c 44 while (i < size - 1)
andrewboyson 128:79052cb4a41c 45 {
andrewboyson 128:79052cb4a41c 46 c = *p++;
andrewboyson 182:ff48c6ea91c1 47 if (c == '.') isExternal = true;
andrewboyson 128:79052cb4a41c 48 if (!c) break;
andrewboyson 128:79052cb4a41c 49 *result++ = c;
andrewboyson 128:79052cb4a41c 50 i++;
andrewboyson 128:79052cb4a41c 51 }
andrewboyson 128:79052cb4a41c 52 if (protocol == DNS_PROTOCOL_MDNS)
andrewboyson 128:79052cb4a41c 53 {
andrewboyson 128:79052cb4a41c 54 p = ".local";
andrewboyson 128:79052cb4a41c 55 while (i < size - 1)
andrewboyson 128:79052cb4a41c 56 {
andrewboyson 128:79052cb4a41c 57 c = *p++;
andrewboyson 128:79052cb4a41c 58 if (!c) break;
andrewboyson 128:79052cb4a41c 59 *result++ = c;
andrewboyson 128:79052cb4a41c 60 i++;
andrewboyson 128:79052cb4a41c 61 }
andrewboyson 128:79052cb4a41c 62 }
andrewboyson 182:ff48c6ea91c1 63 if (protocol == DNS_PROTOCOL_UDNS && !isExternal && DhcpDomainName[0]) //Shouldn't do this in IPv6 as DHCP is IPv4 only
andrewboyson 128:79052cb4a41c 64 {
andrewboyson 128:79052cb4a41c 65 if (i < size - 1)
andrewboyson 128:79052cb4a41c 66 {
andrewboyson 128:79052cb4a41c 67 *result++ = '.';
andrewboyson 128:79052cb4a41c 68 i++;
andrewboyson 128:79052cb4a41c 69 }
andrewboyson 128:79052cb4a41c 70 p = DhcpDomainName;
andrewboyson 128:79052cb4a41c 71 while (i < size - 1)
andrewboyson 128:79052cb4a41c 72 {
andrewboyson 128:79052cb4a41c 73 c = *p++;
andrewboyson 128:79052cb4a41c 74 if (!c) break;
andrewboyson 128:79052cb4a41c 75 *result++ = c;
andrewboyson 128:79052cb4a41c 76 i++;
andrewboyson 128:79052cb4a41c 77 }
andrewboyson 128:79052cb4a41c 78 }
andrewboyson 128:79052cb4a41c 79 *result = 0; //Terminate the resulting string
andrewboyson 128:79052cb4a41c 80 return i;
andrewboyson 128:79052cb4a41c 81 }
andrewboyson 128:79052cb4a41c 82 int DnsLabelStripNameFromFullName(int protocol, char* p, int size, char* result)
andrewboyson 128:79052cb4a41c 83 {
andrewboyson 128:79052cb4a41c 84 int i = 0;
andrewboyson 128:79052cb4a41c 85 char c;
andrewboyson 128:79052cb4a41c 86
andrewboyson 128:79052cb4a41c 87 while (i < size - 1)
andrewboyson 128:79052cb4a41c 88 {
andrewboyson 128:79052cb4a41c 89 c = *p++;
andrewboyson 128:79052cb4a41c 90 if (c == 0) break; //End of the fqdn so stop
andrewboyson 128:79052cb4a41c 91 if (c == '.')
andrewboyson 128:79052cb4a41c 92 {
andrewboyson 128:79052cb4a41c 93 if (protocol == DNS_PROTOCOL_UDNS)
andrewboyson 128:79052cb4a41c 94 {
andrewboyson 128:79052cb4a41c 95 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 128:79052cb4a41c 96 }
andrewboyson 128:79052cb4a41c 97 else
andrewboyson 128:79052cb4a41c 98 {
andrewboyson 128:79052cb4a41c 99 break; //Strip the domain from an LLMNR (there shouldn't be one) or MDNS (it should always be '.local') fqdn
andrewboyson 128:79052cb4a41c 100 }
andrewboyson 128:79052cb4a41c 101 }
andrewboyson 128:79052cb4a41c 102 *result++ = c;
andrewboyson 128:79052cb4a41c 103 i++;
andrewboyson 128:79052cb4a41c 104 }
andrewboyson 128:79052cb4a41c 105 *result = 0; //Terminate the copied string
andrewboyson 128:79052cb4a41c 106 return i;
andrewboyson 128:79052cb4a41c 107 }