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ipn/ipnlocal,wgengine/netstack: move LocalBackend specifc serving logic to LocalBackend

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The netstack code had a bunch of logic to figure out if the LocalBackend should handle an
incoming connection and then would call the function directly on LocalBackend. Move that
logic to LocalBackend and refactor the methods to return conn handlers.

Updates #cleanup

Signed-off-by: Maisem Ali <maisem@tailscale.com>
This commit is contained in:
Maisem Ali
2023-06-08 16:57:40 -07:00
committed by Maisem Ali
parent 5b110685fb
commit fe95d81b43
4 changed files with 125 additions and 127 deletions
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60
wgengine/netstack/netstack.go
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@ -537,10 +537,6 @@ func (ns *Impl) isLocalIP(ip netip.Addr) bool {
return ns.atomicIsLocalIPFunc.Load()(ip)
}
func (ns *Impl) processSSH() bool {
return ns.lb != nil && ns.lb.ShouldRunSSH()
}
func (ns *Impl) peerAPIPortAtomic(ip netip.Addr) *atomic.Uint32 {
if ip.Is4() {
return &ns.peerapiPort4Atomic
@ -840,7 +836,7 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
// request until we're sure that the connection can be handled by this
// endpoint. This function sets up the TCP connection and should be
// called immediately before a connection is handled.
createConn := func(opts ...tcpip.SettableSocketOption) *gonet.TCPConn {
getConnOrReset := func(opts ...tcpip.SettableSocketOption) *gonet.TCPConn {
ep, err := r.CreateEndpoint(&wq)
if err != nil {
ns.logf("CreateEndpoint error for %s: %v", stringifyTEI(reqDetails), err)
@ -879,7 +875,7 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
// DNS
if reqDetails.LocalPort == 53 && (dialIP == magicDNSIP || dialIP == magicDNSIPv6) {
c := createConn()
c := getConnOrReset()
if c == nil {
return
}
@ -888,53 +884,13 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
}
if ns.lb != nil {
if reqDetails.LocalPort == 22 && ns.processSSH() && ns.isLocalIP(dialIP) {
// Use a higher keepalive idle time for SSH connections, as they are
// typically long lived and idle connections are more likely to be
// intentional. Ideally we would turn this off entirely, but we can't
// tell the difference between a long lived connection that is idle
// vs a connection that is dead because the peer has gone away.
// We pick 72h as that is typically sufficient for a long weekend.
idle := tcpip.KeepaliveIdleOption(72 * time.Hour)
c := createConn(&idle)
handler, opts := ns.lb.TCPHandlerForDst(clientRemoteAddrPort, dstAddrPort)
if handler != nil {
c := getConnOrReset(opts...) // will send a RST if it fails
if c == nil {
return
}
if err := ns.lb.HandleSSHConn(c); err != nil {
ns.logf("ssh error: %v", err)
}
return
}
if port, ok := ns.lb.GetPeerAPIPort(dialIP); ok {
if reqDetails.LocalPort == port && ns.isLocalIP(dialIP) {
c := createConn()
if c == nil {
return
}
src := netip.AddrPortFrom(clientRemoteIP, reqDetails.RemotePort)
dst := netip.AddrPortFrom(dialIP, port)
ns.lb.ServePeerAPIConnection(src, dst, c)
return
}
}
if reqDetails.LocalPort == 80 && (dialIP == magicDNSIP || dialIP == magicDNSIPv6) {
c := createConn()
if c == nil {
return
}
ns.lb.HandleQuad100Port80Conn(c)
return
}
if ns.lb.ShouldInterceptTCPPort(reqDetails.LocalPort) && ns.isLocalIP(dialIP) {
getTCPConn := func() (_ net.Conn, ok bool) {
c := createConn()
return c, c != nil
}
sendRST := func() {
r.Complete(true)
}
ns.lb.HandleInterceptedTCPConn(reqDetails.LocalPort, clientRemoteAddrPort, getTCPConn, sendRST)
handler(c)
return
}
}
@ -946,7 +902,7 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
r.Complete(true)
return
}
c := createConn() // will send a RST if it fails
c := getConnOrReset() // will send a RST if it fails
if c == nil {
return
}
@ -959,7 +915,7 @@ func (ns *Impl) acceptTCP(r *tcp.ForwarderRequest) {
}
dialAddr := netip.AddrPortFrom(dialIP, uint16(reqDetails.LocalPort))
if !ns.forwardTCP(createConn, clientRemoteIP, &wq, dialAddr) {
if !ns.forwardTCP(getConnOrReset, clientRemoteIP, &wq, dialAddr) {
r.Complete(true) // sends a RST
}
}