Tom Wilkie
4f3dcf8dc9
The basic data structure used to share information about IP allocations between peers
50 lines
986 B
Go
50 lines
986 B
Go
package utils
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import (
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"net"
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)
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// We shouldn't ever get any errors on *encoding*, but if we do, this will make sure we get to hear about them.
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func panicOnError(err error) {
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if err != nil {
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panic(err)
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}
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}
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// IP4int converts an ipv4 address to a uint32
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func IP4int(ip4 net.IP) (r uint32) {
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for _, b := range ip4.To4() {
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r <<= 8
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r |= uint32(b)
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}
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return
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}
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// IntIP4 converts a uint32 to an ipv4 address
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func IntIP4(key uint32) (r net.IP) {
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r = make([]byte, net.IPv4len)
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for i := 3; i >= 0; i-- {
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r[i] = byte(key)
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key >>= 8
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}
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return
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}
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// Add - convert to 32-bit unsigned integer, add, and convert back
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func Add(addr net.IP, i uint32) net.IP {
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sum := IP4int(addr) + i
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return IntIP4(sum)
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}
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// Subtract - convert to 32-bit unsigned integer, subtract, and convert back
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func Subtract(a, b net.IP) int64 {
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return int64(IP4int(a)) - int64(IP4int(b))
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}
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// Assert test is true, panic otherwise
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func Assert(test bool, message string) {
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if !test {
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panic(message)
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}
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}
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