35 lines
1022 B
Nim
35 lines
1022 B
Nim
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import asyncnet, asyncdispatch, nativesockets
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import strutils, options, tables, strformat
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import ../lib/dns, state
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proc handleDnsRequest(records: RecordsTable, data: string): Option[string] =
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let msg = parseMessage(data)
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if len(msg.questions) == 0:
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return
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let question = msg.questions[0]
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let response = mkResponse(
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msg.header.id,
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question,
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records.getOrDefault((name: question.qname, dtype: question.qtype), @[])
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)
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return some(packMessage(response))
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proc serveDns*(config: AppConfig) {.async.} =
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let dns = newAsyncSocket(sockType=SockType.SOCK_DGRAM, protocol=Protocol.IPPROTO_UDP, buffered = false)
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dns.setSockOpt(OptReuseAddr, true)
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dns.bindAddr(config.dnsPort)
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echo &"DNS listening on port {config.dnsPort.int}"
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while true:
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try:
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let request = await dns.recvFrom(size=512)
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let response = handleDnsRequest(records, request.data)
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if (response.isSome):
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await dns.sendTo(request.address, request.port, response.unsafeGet)
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except:
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continue
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