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/dnsreply.c
- Committer:
- andrewboyson
- Date:
- 2021-05-20
- Revision:
- 200:5acbc41bf469
- Parent:
- 172:9bc3c7b2cca1
File content as of revision 200:5acbc41bf469:
#include <stdint.h> #include <stdbool.h> #include <string.h> #include "log.h" #include "net.h" #include "action.h" #include "ip4.h" #include "ip6.h" #include "nr.h" #include "dns.h" #include "dnshdr.h" #include "dnsname.h" #include "dnslabel.h" #include "dhcp.h" bool DnsReplyTrace = false; char DnsReplyRecordName[256]; uint32_t DnsReplyRecordNameAsIp4 = 0; char DnsReplyRecordNameAsIp6[16]; char DnsReplyName[64]; uint32_t DnsReplyIp4 = 0; char DnsReplyIp6[16]; static char* p; static char* pRecordName; static int recordType; static int recordDataLength; static char* pRecordData; static int scanQuery() { int recordNameLength = DnsNameLength(p); if (!recordNameLength) return -1; //failure pRecordName = p; p += recordNameLength; p++ ; //skip the first byte of the type recordType = *p++; p += 2; //skip the class return 0; //success } static int scanAnswer() { int recordNameLength = DnsNameLength(p); if (!recordNameLength) return -1; //failure pRecordName = p; p += recordNameLength; p++ ; //skip the first byte of the type recordType = *p++; p += 6; //skip the class, TTL recordDataLength = 0; recordDataLength |= *p++ << 8; recordDataLength |= *p++; pRecordData = p; //record the start of the data p += recordDataLength; //Move to the start of the next record return 0; //success } static void readAnswer() { DnsReplyRecordName[0] = 0; DnsReplyRecordNameAsIp4 = 0; DnsReplyRecordNameAsIp6[0] = 0; DnsReplyName[0] = 0; DnsReplyIp4 = 0; DnsReplyIp6[0] = 0; switch (recordType) { case DNS_RECORD_A: case DNS_RECORD_AAAA: case DNS_RECORD_PTR: case DNS_RECORD_SRV: case DNS_RECORD_TXT: break; default: return; } DnsNameDecodePtr(pRecordName, DnsReplyRecordName, sizeof(DnsReplyRecordName)); DnsNameDecodeIp4(pRecordName, &DnsReplyRecordNameAsIp4); DnsNameDecodeIp6(pRecordName, DnsReplyRecordNameAsIp6); switch (recordType) { case DNS_RECORD_A: if (recordDataLength != 4) return; memcpy(&DnsReplyIp4, pRecordData, 4); break; case DNS_RECORD_AAAA: if (recordDataLength != 16) return; memcpy(DnsReplyIp6, pRecordData, 16); break; case DNS_RECORD_PTR: if (recordDataLength > DNS_MAX_LABEL_LENGTH) return; DnsNameDecodePtr(pRecordData, DnsReplyName, sizeof(DnsReplyName)); break; } } static void sendToDnsCache(int dnsProtocol) { char strippedName[100]; if (DnsReplyRecordName[0]) DnsLabelStripNameFromFullName(dnsProtocol, DnsReplyRecordName, sizeof(strippedName), strippedName); if (DnsReplyName[0] ) DnsLabelStripNameFromFullName(dnsProtocol, DnsReplyName , sizeof(strippedName), strippedName); if (DnsReplyIp4 && DnsReplyRecordName[0]) NrAddAddress4(DnsReplyIp4, strippedName, dnsProtocol); if (DnsReplyIp6[0] && DnsReplyRecordName[0]) NrAddAddress6(DnsReplyIp6, strippedName, dnsProtocol); if (DnsReplyRecordNameAsIp4 && DnsReplyName[0] ) NrAddAddress4(DnsReplyRecordNameAsIp4, strippedName, dnsProtocol); if (DnsReplyRecordNameAsIp6[0] && DnsReplyName[0] ) NrAddAddress6(DnsReplyRecordNameAsIp6, strippedName, dnsProtocol); } int DnsReplyHandle(void (*traceback)(void), int dnsProtocol) { bool ok = true; if (!DnsHdrAncount) ok = false; p = DnsHdrData; if (DnsReplyTrace || NetTraceHostGetMatched()) { if (NetTraceNewLine) Log("\r\n"); LogTimeF("DnsReply received\r\n"); if (NetTraceStack) traceback(); DnsHdrLog(dnsProtocol); } if (ok) { for (int q = 0; q < DnsHdrQdcount; q++) { if (scanQuery()) { ok = false; break; } } } if (ok) { for (int a = 0; a < DnsHdrAncount; a++) { if (scanAnswer()) { ok = false; break; } readAnswer(); sendToDnsCache(dnsProtocol); } } NetTraceHostCheckIp6(DnsReplyIp6); NetTraceHostCheckIp6(DnsReplyRecordNameAsIp6); return DO_NOTHING; }