addr.go 7.76 KB
Newer Older
Juan Batiz-Benet's avatar
Juan Batiz-Benet committed
1 2 3 4 5
package addrutil

import (
	"fmt"

Jeromy's avatar
Jeromy committed
6
	logging "QmWRypnfEwrgH4k93KEHN5hng7VjKYkWmzDYRuTZeh2Mgh/go-log"
Juan Batiz-Benet's avatar
Juan Batiz-Benet committed
7

Jeromy's avatar
Jeromy committed
8 9 10
	ma "github.com/jbenet/go-multiaddr"
	manet "github.com/jbenet/go-multiaddr-net"
	context "golang.org/x/net/context"
Juan Batiz-Benet's avatar
Juan Batiz-Benet committed
11 12
)

Jeromy's avatar
Jeromy committed
13
var log = logging.Logger("github.com/ipfs/go-libp2p/p2p/net/swarm/addr")
Juan Batiz-Benet's avatar
Juan Batiz-Benet committed
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275

// SupportedTransportStrings is the list of supported transports for the swarm.
// These are strings of encapsulated multiaddr protocols. E.g.:
//   /ip4/tcp
var SupportedTransportStrings = []string{
	"/ip4/tcp",
	"/ip6/tcp",
	// "/ip4/udp/utp", disabled because the lib is broken
	// "/ip6/udp/utp", disabled because the lib is broken
	// "/ip4/udp/udt", disabled because the lib doesnt work on arm
	// "/ip6/udp/udt", disabled because the lib doesnt work on arm
}

// SupportedTransportProtocols is the list of supported transports for the swarm.
// These are []ma.Protocol lists. Populated at runtime from SupportedTransportStrings
var SupportedTransportProtocols = [][]ma.Protocol{}

func init() {
	// initialize SupportedTransportProtocols
	transports := make([][]ma.Protocol, len(SupportedTransportStrings))
	for _, s := range SupportedTransportStrings {
		t, err := ma.ProtocolsWithString(s)
		if err != nil {
			panic(err) // important to fix this in the codebase
		}
		transports = append(transports, t)
	}
	SupportedTransportProtocols = transports
}

// FilterAddrs is a filter that removes certain addresses, according to filter.
// if filter returns true, the address is kept.
func FilterAddrs(a []ma.Multiaddr, filter func(ma.Multiaddr) bool) []ma.Multiaddr {
	b := make([]ma.Multiaddr, 0, len(a))
	for _, addr := range a {
		if filter(addr) {
			b = append(b, addr)
		}
	}
	return b
}

// FilterUsableAddrs removes certain addresses
// from a list. the addresses removed are those known NOT
// to work with our network. Namely, addresses with UTP.
func FilterUsableAddrs(a []ma.Multiaddr) []ma.Multiaddr {
	return FilterAddrs(a, func(m ma.Multiaddr) bool {
		return AddrUsable(m, false)
	})
}

// AddrOverNonLocalIP returns whether the addr uses a non-local ip link
func AddrOverNonLocalIP(a ma.Multiaddr) bool {
	split := ma.Split(a)
	if len(split) < 1 {
		return false
	}
	if manet.IsIP6LinkLocal(split[0]) {
		return false
	}
	return true
}

// AddrUsable returns whether our network can use this addr.
// We only use the transports in SupportedTransportStrings,
// and we do not link local addresses. Loopback is ok
// as we need to be able to connect to multiple ipfs nodes
// in the same machine.
func AddrUsable(a ma.Multiaddr, partial bool) bool {
	if a == nil {
		return false
	}

	if !AddrOverNonLocalIP(a) {
		return false
	}

	// test the address protocol list is in SupportedTransportProtocols
	matches := func(supported, test []ma.Protocol) bool {
		if len(test) > len(supported) {
			return false
		}

		// when partial, it's ok if test < supported.
		if !partial && len(supported) != len(test) {
			return false
		}

		for i := range test {
			if supported[i].Code != test[i].Code {
				return false
			}
		}
		return true
	}

	transport := a.Protocols()
	for _, supported := range SupportedTransportProtocols {
		if matches(supported, transport) {
			return true
		}
	}

	return false
}

// ResolveUnspecifiedAddress expands an unspecified ip addresses (/ip4/0.0.0.0, /ip6/::) to
// use the known local interfaces. If ifaceAddr is nil, we request interface addresses
// from the network stack. (this is so you can provide a cached value if resolving many addrs)
func ResolveUnspecifiedAddress(resolve ma.Multiaddr, ifaceAddrs []ma.Multiaddr) ([]ma.Multiaddr, error) {
	// split address into its components
	split := ma.Split(resolve)

	// if first component (ip) is not unspecified, use it as is.
	if !manet.IsIPUnspecified(split[0]) {
		return []ma.Multiaddr{resolve}, nil
	}

	out := make([]ma.Multiaddr, 0, len(ifaceAddrs))
	for _, ia := range ifaceAddrs {
		// must match the first protocol to be resolve.
		if ia.Protocols()[0].Code != resolve.Protocols()[0].Code {
			continue
		}

		split[0] = ia
		joined := ma.Join(split...)
		out = append(out, joined)
		log.Debug("adding resolved addr:", resolve, joined, out)
	}
	if len(out) < 1 {
		return nil, fmt.Errorf("failed to resolve: %s", resolve)
	}
	return out, nil
}

// ResolveUnspecifiedAddresses expands unspecified ip addresses (/ip4/0.0.0.0, /ip6/::) to
// use the known local interfaces.
func ResolveUnspecifiedAddresses(unspecAddrs, ifaceAddrs []ma.Multiaddr) ([]ma.Multiaddr, error) {

	// todo optimize: only fetch these if we have a "any" addr.
	if len(ifaceAddrs) < 1 {
		var err error
		ifaceAddrs, err = InterfaceAddresses()
		if err != nil {
			return nil, err
		}
		// log.Debug("InterfaceAddresses:", ifaceAddrs)
	}

	var outputAddrs []ma.Multiaddr
	for _, a := range unspecAddrs {
		// unspecified?
		resolved, err := ResolveUnspecifiedAddress(a, ifaceAddrs)
		if err != nil {
			continue // optimistic. if we cant resolve anything, we'll know at the bottom.
		}
		// log.Debug("resolved:", a, resolved)
		outputAddrs = append(outputAddrs, resolved...)
	}

	if len(outputAddrs) < 1 {
		return nil, fmt.Errorf("failed to specify addrs: %s", unspecAddrs)
	}

	log.Event(context.TODO(), "interfaceListenAddresses", func() logging.Loggable {
		var addrs []string
		for _, addr := range outputAddrs {
			addrs = append(addrs, addr.String())
		}
		return logging.Metadata{"addresses": addrs}
	}())

	log.Debug("ResolveUnspecifiedAddresses:", unspecAddrs, ifaceAddrs, outputAddrs)
	return outputAddrs, nil
}

// InterfaceAddresses returns a list of addresses associated with local machine
// Note: we do not return link local addresses. IP loopback is ok, because we
// may be connecting to other nodes in the same machine.
func InterfaceAddresses() ([]ma.Multiaddr, error) {
	maddrs, err := manet.InterfaceMultiaddrs()
	if err != nil {
		return nil, err
	}
	log.Debug("InterfaceAddresses: from manet:", maddrs)

	var out []ma.Multiaddr
	for _, a := range maddrs {
		if !AddrUsable(a, true) { // partial
			// log.Debug("InterfaceAddresses: skipping unusable:", a)
			continue
		}

		out = append(out, a)
	}

	log.Debug("InterfaceAddresses: usable:", out)
	return out, nil
}

// AddrInList returns whether or not an address is part of a list.
// this is useful to check if NAT is happening (or other bugs?)
func AddrInList(addr ma.Multiaddr, list []ma.Multiaddr) bool {
	for _, addr2 := range list {
		if addr.Equal(addr2) {
			return true
		}
	}
	return false
}

// AddrIsShareableOnWAN returns whether the given address should be shareable on the
// wide area network (wide internet).
func AddrIsShareableOnWAN(addr ma.Multiaddr) bool {
	s := ma.Split(addr)
	if len(s) < 1 {
		return false
	}
	a := s[0]
	if manet.IsIPLoopback(a) || manet.IsIP6LinkLocal(a) || manet.IsIPUnspecified(a) {
		return false
	}
	return manet.IsThinWaist(a)
}

// WANShareableAddrs filters addresses based on whether they're shareable on WAN
func WANShareableAddrs(inp []ma.Multiaddr) []ma.Multiaddr {
	return FilterAddrs(inp, AddrIsShareableOnWAN)
}

// Subtract filters out all addrs in b from a
func Subtract(a, b []ma.Multiaddr) []ma.Multiaddr {
	return FilterAddrs(a, func(m ma.Multiaddr) bool {
		for _, bb := range b {
			if m.Equal(bb) {
				return false
			}
		}
		return true
	})
}

// CheckNATWarning checks if our observed addresses differ. if so,
// informs the user that certain things might not work yet
func CheckNATWarning(observed, expected ma.Multiaddr, listen []ma.Multiaddr) {
	if observed.Equal(expected) {
		return
	}

	if !AddrInList(observed, listen) { // probably a nat
		log.Warningf(natWarning, observed, listen)
	}
}

const natWarning = `Remote peer observed our address to be: %s
The local addresses are: %s
Thus, connection is going through NAT, and other connections may fail.

IPFS NAT traversal is still under development. Please bug us on github or irc to fix this.
Baby steps: http://jbenet.static.s3.amazonaws.com/271dfcf/baby-steps.gif
`