@ -20,8 +20,12 @@ import (
"inet.af/netaddr"
"tailscale.com/net/dnscache"
"tailscale.com/net/interfaces"
"tailscale.com/net/netknob"
"tailscale.com/net/netns"
"tailscale.com/types/logger"
"tailscale.com/types/netmap"
"tailscale.com/util/mak"
"tailscale.com/wgengine/monitor"
)
@ -30,6 +34,7 @@ import (
// (TUN, netstack), the OS network sandboxing style (macOS/iOS
// Extension, none), user-selected route acceptance prefs, etc.
type Dialer struct {
Logf logger . Logf
// UseNetstackForIP if non-nil is whether NetstackDialTCP (if
// it's non-nil) should be used to dial the provided IP.
UseNetstackForIP func ( netaddr . IP ) bool
@ -46,12 +51,33 @@ type Dialer struct {
peerDialerOnce sync . Once
peerDialer * net . Dialer
mu sync . Mutex
dns dnsMap
tunName string // tun device name
linkMon * monitor . Mon
exitDNSDoHBase string // non-empty if DoH-proxying exit node in use; base URL+path (without '?')
dnsCache * dnscache . MessageCache // nil until first first non-empty SetExitDNSDoH
netnsDialerOnce sync . Once
netnsDialer netns . Dialer
mu sync . Mutex
closed bool
dns dnsMap
tunName string // tun device name
linkMon * monitor . Mon
linkMonUnregister func ( )
exitDNSDoHBase string // non-empty if DoH-proxying exit node in use; base URL+path (without '?')
dnsCache * dnscache . MessageCache // nil until first first non-empty SetExitDNSDoH
nextSysConnID int
activeSysConns map [ int ] net . Conn // active connections not yet closed
}
// sysConn wraps a net.Conn that was created using d.SystemDial.
// It exists to track which connections are still open, and should be
// closed on major link changes.
type sysConn struct {
net . Conn
id int
d * Dialer
}
func ( c sysConn ) Close ( ) error {
c . d . closeSysConn ( c . id )
return nil
}
// SetTUNName sets the name of the tun device in use ("tailscale0", "utun6",
@ -91,10 +117,53 @@ func (d *Dialer) SetExitDNSDoH(doh string) {
}
}
func ( d * Dialer ) Close ( ) error {
d . mu . Lock ( )
defer d . mu . Unlock ( )
d . closed = true
if d . linkMonUnregister != nil {
d . linkMonUnregister ( )
d . linkMonUnregister = nil
}
for _ , c := range d . activeSysConns {
c . Close ( )
}
d . activeSysConns = nil
return nil
}
func ( d * Dialer ) SetLinkMonitor ( mon * monitor . Mon ) {
d . mu . Lock ( )
defer d . mu . Unlock ( )
if d . linkMonUnregister != nil {
go d . linkMonUnregister ( )
d . linkMonUnregister = nil
}
d . linkMon = mon
d . linkMonUnregister = d . linkMon . RegisterChangeCallback ( d . linkChanged )
}
func ( d * Dialer ) linkChanged ( major bool , state * interfaces . State ) {
if ! major {
return
}
d . mu . Lock ( )
defer d . mu . Unlock ( )
for id , c := range d . activeSysConns {
go c . Close ( )
delete ( d . activeSysConns , id )
}
}
func ( d * Dialer ) closeSysConn ( id int ) {
d . mu . Lock ( )
defer d . mu . Unlock ( )
c , ok := d . activeSysConns [ id ]
if ! ok {
return
}
delete ( d . activeSysConns , id )
go c . Close ( ) // ignore the error
}
func ( d * Dialer ) interfaceIndexLocked ( ifName string ) ( index int , ok bool ) {
@ -197,6 +266,42 @@ func ipNetOfNetwork(n string) string {
return "ip"
}
// SystemDial connects to the provided network address without going over
// Tailscale. It prefers going over the default interface and closes existing
// connections if the default interface changes. It is used to connect to
// Control and (in the future, as of 2022-04-27) DERPs..
func ( d * Dialer ) SystemDial ( ctx context . Context , network , addr string ) ( net . Conn , error ) {
d . mu . Lock ( )
closed := d . closed
d . mu . Unlock ( )
if closed {
return nil , net . ErrClosed
}
d . netnsDialerOnce . Do ( func ( ) {
logf := d . Logf
if logf == nil {
logf = logger . Discard
}
d . netnsDialer = netns . NewDialer ( logf )
} )
c , err := d . netnsDialer . DialContext ( ctx , network , addr )
if err != nil {
return nil , err
}
d . mu . Lock ( )
defer d . mu . Unlock ( )
id := d . nextSysConnID
d . nextSysConnID ++
mak . Set ( & d . activeSysConns , id , c )
return sysConn {
id : id ,
d : d ,
Conn : c ,
} , nil
}
// UserDial connects to the provided network address as if a user were initiating the dial.
// (e.g. from a SOCKS or HTTP outbound proxy)
func ( d * Dialer ) UserDial ( ctx context . Context , network , addr string ) ( net . Conn , error ) {
Maisem Ali
3 years ago
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