mediocre-go-lib/mnet/mnet.go

109 lines
3.6 KiB
Go

// Package mnet extends the standard package with extra functionality which is
// commonly useful
package mnet
import (
"net"
"github.com/mediocregopher/mediocre-go-lib/mcfg"
"github.com/mediocregopher/mediocre-go-lib/mctx"
"github.com/mediocregopher/mediocre-go-lib/mlog"
"github.com/mediocregopher/mediocre-go-lib/mrun"
)
// MListen returns a Listener which will be initialized when the start event is
// triggered on ctx (see mrun.Start), and closed when the stop event is
// triggered on ctx (see mrun.Stop).
//
// network defaults to "tcp" if empty. defaultAddr defaults to ":0" if empty,
// and will be configurable via mcfg.
func MListen(ctx mctx.Context, network, defaultAddr string) net.Listener {
if network == "" {
network = "tcp"
}
if defaultAddr == "" {
defaultAddr = ":0"
}
addr := mcfg.String(ctx, "addr", defaultAddr, network+" address to listen on in format [host]:port. If port is 0 then a random one will be chosen")
var l struct{ net.Listener }
mrun.OnStart(ctx, func(mctx.Context) error {
var err error
if l.Listener, err = net.Listen(network, *addr); err != nil {
return err
}
mlog.From(ctx).Info("listening", mlog.KV{"addr": l.Addr()})
return nil
})
// TODO track connections and wait for them to complete before shutting
// down?
mrun.OnStop(ctx, func(mctx.Context) error {
return l.Close()
})
return &l
}
////////////////////////////////////////////////////////////////////////////////
func mustGetCIDRNetwork(cidr string) *net.IPNet {
_, n, err := net.ParseCIDR(cidr)
if err != nil {
panic(err)
}
return n
}
// https://en.wikipedia.org/wiki/Reserved_IP_addresses
var reservedCIDRs4 = []*net.IPNet{
mustGetCIDRNetwork("0.0.0.0/8"), // current network
mustGetCIDRNetwork("10.0.0.0/8"), // private network
mustGetCIDRNetwork("100.64.0.0/10"), // private network
mustGetCIDRNetwork("127.0.0.0/8"), // localhost
mustGetCIDRNetwork("169.254.0.0/16"), // link-local
mustGetCIDRNetwork("172.16.0.0/12"), // private network
mustGetCIDRNetwork("192.0.0.0/24"), // IETF protocol assignments
mustGetCIDRNetwork("192.0.2.0/24"), // documentation and examples
mustGetCIDRNetwork("192.88.99.0/24"), // 6to4 Relay
mustGetCIDRNetwork("192.168.0.0/16"), // private network
mustGetCIDRNetwork("198.18.0.0/15"), // private network
mustGetCIDRNetwork("198.51.100.0/24"), // documentation and examples
mustGetCIDRNetwork("203.0.113.0/24"), // documentation and examples
mustGetCIDRNetwork("224.0.0.0/4"), // IP multicast
mustGetCIDRNetwork("240.0.0.0/4"), // reserved
mustGetCIDRNetwork("255.255.255.255/32"), // limited broadcast address
}
var reservedCIDRs6 = []*net.IPNet{
mustGetCIDRNetwork("::/128"), // unspecified address
mustGetCIDRNetwork("::1/128"), // loopback address
mustGetCIDRNetwork("100::/64"), // discard prefix
mustGetCIDRNetwork("2001::/32"), // Teredo tunneling
mustGetCIDRNetwork("2001:20::/28"), // ORCHID v2
mustGetCIDRNetwork("2001:db8::/32"), // documentation and examples
mustGetCIDRNetwork("2002::/16"), // 6to4 addressing
mustGetCIDRNetwork("fc00::/7"), // unique local
mustGetCIDRNetwork("fe80::/10"), // link local
mustGetCIDRNetwork("ff00::/8"), // multicast
}
// IsReservedIP returns true if the given valid IP is part of a reserved IP
// range.
func IsReservedIP(ip net.IP) bool {
containedBy := func(cidrs []*net.IPNet) bool {
for _, cidr := range cidrs {
if cidr.Contains(ip) {
return true
}
}
return false
}
if ip.To4() != nil {
return containedBy(reservedCIDRs4)
}
return containedBy(reservedCIDRs6)
}