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Diffstat (limited to 'p2p/netutil/net.go')
| -rw-r--r-- | p2p/netutil/net.go | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/p2p/netutil/net.go b/p2p/netutil/net.go new file mode 100644 index 000000000..3c3715788 --- /dev/null +++ b/p2p/netutil/net.go @@ -0,0 +1,166 @@ +// Copyright 2016 The go-ethereum Authors +// This file is part of the go-ethereum library. +// +// The go-ethereum library is free software: you can redistribute it and/or modify +// it under the terms of the GNU Lesser General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. +// +// The go-ethereum library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU Lesser General Public License for more details. +// +// You should have received a copy of the GNU Lesser General Public License +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. + +// Package netutil contains extensions to the net package. +package netutil + +import ( + "errors" + "net" + "strings" +) + +var lan4, lan6, special4, special6 Netlist + +func init() { + // Lists from RFC 5735, RFC 5156, + // https://www.iana.org/assignments/iana-ipv4-special-registry/ + lan4.Add("0.0.0.0/8") // "This" network + lan4.Add("10.0.0.0/8") // Private Use + lan4.Add("172.16.0.0/12") // Private Use + lan4.Add("192.168.0.0/16") // Private Use + lan6.Add("fe80::/10") // Link-Local + lan6.Add("fc00::/7") // Unique-Local + special4.Add("192.0.0.0/29") // IPv4 Service Continuity + special4.Add("192.0.0.9/32") // PCP Anycast + special4.Add("192.0.0.170/32") // NAT64/DNS64 Discovery + special4.Add("192.0.0.171/32") // NAT64/DNS64 Discovery + special4.Add("192.0.2.0/24") // TEST-NET-1 + special4.Add("192.31.196.0/24") // AS112 + special4.Add("192.52.193.0/24") // AMT + special4.Add("192.88.99.0/24") // 6to4 Relay Anycast + special4.Add("192.175.48.0/24") // AS112 + special4.Add("198.18.0.0/15") // Device Benchmark Testing + special4.Add("198.51.100.0/24") // TEST-NET-2 + special4.Add("203.0.113.0/24") // TEST-NET-3 + special4.Add("255.255.255.255/32") // Limited Broadcast + + // http://www.iana.org/assignments/iana-ipv6-special-registry/ + special6.Add("100::/64") + special6.Add("2001::/32") + special6.Add("2001:1::1/128") + special6.Add("2001:2::/48") + special6.Add("2001:3::/32") + special6.Add("2001:4:112::/48") + special6.Add("2001:5::/32") + special6.Add("2001:10::/28") + special6.Add("2001:20::/28") + special6.Add("2001:db8::/32") + special6.Add("2002::/16") +} + +// Netlist is a list of IP networks. +type Netlist []net.IPNet + +// ParseNetlist parses a comma-separated list of CIDR masks. +// Whitespace and extra commas are ignored. +func ParseNetlist(s string) (*Netlist, error) { + ws := strings.NewReplacer(" ", "", "\n", "", "\t", "") + masks := strings.Split(ws.Replace(s), ",") + l := make(Netlist, 0) + for _, mask := range masks { + if mask == "" { + continue + } + _, n, err := net.ParseCIDR(mask) + if err != nil { + return nil, err + } + l = append(l, *n) + } + return &l, nil +} + +// Add parses a CIDR mask and appends it to the list. It panics for invalid masks and is +// intended to be used for setting up static lists. +func (l *Netlist) Add(cidr string) { + _, n, err := net.ParseCIDR(cidr) + if err != nil { + panic(err) + } + *l = append(*l, *n) +} + +// Contains reports whether the given IP is contained in the list. +func (l *Netlist) Contains(ip net.IP) bool { + if l == nil { + return false + } + for _, net := range *l { + if net.Contains(ip) { + return true + } + } + return false +} + +// IsLAN reports whether an IP is a local network address. +func IsLAN(ip net.IP) bool { + if ip.IsLoopback() { + return true + } + if v4 := ip.To4(); v4 != nil { + return lan4.Contains(v4) + } + return lan6.Contains(ip) +} + +// IsSpecialNetwork reports whether an IP is located in a special-use network range +// This includes broadcast, multicast and documentation addresses. +func IsSpecialNetwork(ip net.IP) bool { + if ip.IsMulticast() { + return true + } + if v4 := ip.To4(); v4 != nil { + return special4.Contains(v4) + } + return special6.Contains(ip) +} + +var ( + errInvalid = errors.New("invalid IP") + errUnspecified = errors.New("zero address") + errSpecial = errors.New("special network") + errLoopback = errors.New("loopback address from non-loopback host") + errLAN = errors.New("LAN address from WAN host") +) + +// CheckRelayIP reports whether an IP relayed from the given sender IP +// is a valid connection target. +// +// There are four rules: +// - Special network addresses are never valid. +// - Loopback addresses are OK if relayed by a loopback host. +// - LAN addresses are OK if relayed by a LAN host. +// - All other addresses are always acceptable. +func CheckRelayIP(sender, addr net.IP) error { + if len(addr) != net.IPv4len && len(addr) != net.IPv6len { + return errInvalid + } + if addr.IsUnspecified() { + return errUnspecified + } + if IsSpecialNetwork(addr) { + return errSpecial + } + if addr.IsLoopback() && !sender.IsLoopback() { + return errLoopback + } + if IsLAN(addr) && !IsLAN(sender) { + return errLAN + } + return nil +} |