Go/GoLang check IP address in range

Question

In Go/GoLang, what is the fastest way to check if an IP address is in a specific range?

For example, given range 216.14.49.184 to 216.14.49.191, how would I check if a given input IP address is in that range?

Answer 1

IP addresses are represented as bigendian []byte slices in go (the IP type) so will compare correctly using bytes.Compare.

Eg (play)

package main  import (     "bytes"     "fmt"     "net" )  var (     ip1 = net.ParseIP("216.14.49.184")     ip2 = net.ParseIP("216.14.49.191") )  func check(ip string) bool {     trial := net.ParseIP(ip)     if trial.To4() == nil {         fmt.Printf("%v is not an IPv4 address\n", trial)         return false     }     if bytes.Compare(trial, ip1) >= 0 && bytes.Compare(trial, ip2) <= 0 {         fmt.Printf("%v is between %v and %v\n", trial, ip1, ip2)         return true     }     fmt.Printf("%v is NOT between %v and %v\n", trial, ip1, ip2)     return false }  func main() {     check("1.2.3.4")     check("216.14.49.185")     check("1::16") } 

Which produces

1.2.3.4 is NOT between 216.14.49.184 and 216.14.49.191 216.14.49.185 is between 216.14.49.184 and 216.14.49.191 1::16 is not an IPv4 address