From ec371af84f133167b6310c1ffa827b72a9e6dc66 Mon Sep 17 00:00:00 2001 From: Neil Alexander Date: Fri, 18 May 2018 17:59:29 +0100 Subject: [PATCH 1/2] Track TX/RX bytes over session and if MTU was adjusted, add to admin socket getSession --- src/yggdrasil/admin.go | 3 +++ src/yggdrasil/session.go | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/src/yggdrasil/admin.go b/src/yggdrasil/admin.go index 3270365..db485d1 100644 --- a/src/yggdrasil/admin.go +++ b/src/yggdrasil/admin.go @@ -374,6 +374,9 @@ func (a *admin) getData_getSessions() []admin_nodeInfo { {"IP", net.IP(sinfo.theirAddr[:]).String()}, {"coords", fmt.Sprint(sinfo.coords)}, {"MTU", fmt.Sprint(sinfo.getMTU())}, + {"wasMTUFixed", fmt.Sprint(sinfo.wasMTUFixed)}, + {"bytesSent", fmt.Sprint(sinfo.bytesSent)}, + {"bytesRecvd", fmt.Sprint(sinfo.bytesRecvd)}, } infos = append(infos, info) } diff --git a/src/yggdrasil/session.go b/src/yggdrasil/session.go index f413174..df76042 100644 --- a/src/yggdrasil/session.go +++ b/src/yggdrasil/session.go @@ -21,6 +21,7 @@ type sessionInfo struct { myNonce boxNonce theirMTU uint16 myMTU uint16 + wasMTUFixed bool // Was the MTU fixed by a receive error? time time.Time // Time we last received a packet coords []byte // coords of destination packet []byte // a buffered packet, sent immediately on ping/pong @@ -32,6 +33,8 @@ type sessionInfo struct { mtuTime time.Time // time myMTU was last changed pingTime time.Time // time the first ping was sent since the last received packet pingSend time.Time // time the last ping was sent + bytesSent uint64 // Bytes of real traffic sent in this session + bytesRecvd uint64 // Bytes of real traffic received in this session } type sessionPing struct { @@ -384,6 +387,7 @@ func (sinfo *sessionInfo) doSend(bs []byte) { payload: payload, } packet := p.encode() + sinfo.bytesSent += uint64(len(bs)) sinfo.core.router.out(packet) } @@ -411,6 +415,7 @@ func (sinfo *sessionInfo) doRecv(p *wire_trafficPacket) { //sinfo.core.log.Println("DEBUG set MTU to:", sinfo.myMTU) sinfo.core.sessions.sendPingPong(sinfo, false) sinfo.mtuTime = time.Now() + sinfo.wasMTUFixed = true } } go func() { sinfo.core.router.admin <- fixSessionMTU }() @@ -427,5 +432,6 @@ func (sinfo *sessionInfo) doRecv(p *wire_trafficPacket) { go func() { sinfo.core.router.admin <- fixSessionMTU }() sinfo.updateNonce(&p.nonce) sinfo.time = time.Now() + sinfo.bytesRecvd += uint64(len(bs)) sinfo.core.router.recvPacket(bs, &sinfo.theirAddr, &sinfo.theirSubnet) } From ca96bbf01457fbc6fed668fb78af05207026c0e9 Mon Sep 17 00:00:00 2001 From: Neil Alexander Date: Fri, 18 May 2018 18:56:33 +0100 Subject: [PATCH 2/2] Accept exchanging an MTU of 0 to signify that TUN/TAP is disabled, don't send traffic to a node in that case --- src/yggdrasil/admin.go | 11 +++++++++++ src/yggdrasil/router.go | 25 +++++++++++++++++++++++++ src/yggdrasil/session.go | 5 ++++- 3 files changed, 40 insertions(+), 1 deletion(-) diff --git a/src/yggdrasil/admin.go b/src/yggdrasil/admin.go index db485d1..75561bd 100644 --- a/src/yggdrasil/admin.go +++ b/src/yggdrasil/admin.go @@ -280,6 +280,17 @@ func (a *admin) startTunWithMTU(ifname string, iftapmode bool, ifmtu int) error if err != nil { return err } + // If we have open sessions then we need to notify them + // that our MTU has now changed + for _, sinfo := range a.core.sessions.sinfos { + if ifname == "none" { + sinfo.myMTU = 0 + } else { + sinfo.myMTU = uint16(ifmtu) + } + a.core.sessions.sendPingPong(sinfo, false) + } + // Aaaaand... go! go a.core.tun.read() } go a.core.tun.write() diff --git a/src/yggdrasil/router.go b/src/yggdrasil/router.go index 78bfa36..ad11d6e 100644 --- a/src/yggdrasil/router.go +++ b/src/yggdrasil/router.go @@ -164,6 +164,31 @@ func (r *router) sendPacket(bs []byte) { } fallthrough // Also send the packet default: + // Drop packets if the session MTU is 0 - this means that one or other + // side probably has their TUN adapter disabled + if sinfo.getMTU() == 0 { + // Get the size of the oversized payload, up to a max of 900 bytes + window := 900 + if len(bs) < window { + window = len(bs) + } + + // Create the Destination Unreachable response + ptb := &icmp.DstUnreach{ + Data: bs[:window], + } + + // Create the ICMPv6 response from it + icmpv6Buf, err := r.core.tun.icmpv6.create_icmpv6_tun( + bs[8:24], bs[24:40], + ipv6.ICMPTypeDestinationUnreachable, 1, ptb) + if err == nil { + r.recv <- icmpv6Buf + } + + // Don't continue - drop the packet + return + } // Generate an ICMPv6 Packet Too Big for packets larger than session MTU if len(bs) > int(sinfo.getMTU()) { // Get the size of the oversized payload, up to a max of 900 bytes diff --git a/src/yggdrasil/session.go b/src/yggdrasil/session.go index df76042..090c973 100644 --- a/src/yggdrasil/session.go +++ b/src/yggdrasil/session.go @@ -65,7 +65,7 @@ func (s *sessionInfo) update(p *sessionPing) bool { s.theirNonce = boxNonce{} s.nonceMask = 0 } - if p.mtu >= 1280 { + if p.mtu >= 1280 || p.mtu == 0 { s.theirMTU = p.mtu } s.coords = append([]byte{}, p.coords...) @@ -313,6 +313,9 @@ func (n *boxNonce) minus(m *boxNonce) int64 { } func (sinfo *sessionInfo) getMTU() uint16 { + if sinfo.theirMTU == 0 || sinfo.myMTU == 0 { + return 0 + } if sinfo.theirMTU < sinfo.myMTU { return sinfo.theirMTU }