75 lines
1.2 KiB
Go
75 lines
1.2 KiB
Go
package resolve
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import (
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"context"
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"net"
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"runtime"
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"sort"
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"strings"
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"sync"
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"time"
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)
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type ReverseResult struct {
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IP string `json:"ip"`
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Hostname string `json:"hostname,omitempty"`
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}
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func ReverseLookupAll(ctx context.Context, ips []string, timeout time.Duration, jobs int) []ReverseResult {
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if jobs <= 0 {
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jobs = runtime.GOMAXPROCS(0)
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}
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in := make(chan string)
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out := make(chan ReverseResult)
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var wg sync.WaitGroup
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worker := func() {
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defer wg.Done()
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for ip := range in {
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r := ReverseResult{IP: ip}
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cctx, cancel := context.WithTimeout(ctx, timeout)
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names, err := net.DefaultResolver.LookupAddr(cctx, ip)
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cancel()
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if err == nil && len(names) > 0 {
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// trim trailing dot for readability
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r.Hostname = strings.TrimSuffix(names[0], ".")
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}
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select {
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case out <- r:
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case <-ctx.Done():
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return
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}
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}
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}
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wg.Add(jobs)
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for i := 0; i < jobs; i++ {
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go worker()
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}
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go func() {
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defer close(in)
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for _, ip := range ips {
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select {
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case in <- ip:
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case <-ctx.Done():
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return
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}
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}
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}()
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go func() {
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wg.Wait()
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close(out)
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}()
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var res []ReverseResult
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for r := range out {
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res = append(res, r)
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}
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sort.Slice(res, func(i, j int) bool { return res[i].IP < res[j].IP })
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return res
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}
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