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wgengine/magicsock: use derp-region-as-magic-AddrPort hack in fewer places

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And fix up a bogus comment and flesh out some other comments.

Updates #cleanup

Change-Id: Ia60a1c04b0f5e44e8d9587914af819df8e8f442a
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick 2024-07-06 19:20:15 -07:00 committed by Brad Fitzpatrick
parent e181f12a7b
commit 9df107f4f0
2 changed files with 19 additions and 22 deletions
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34
wgengine/magicsock/derp.go
View File

@ -258,14 +258,14 @@ func (c *Conn) startDerpHomeConnectLocked() {
}
// goDerpConnect starts a goroutine to start connecting to the given
// DERP node.
// DERP region ID.
//
// c.mu may be held, but does not need to be.
func (c *Conn) goDerpConnect(node int) {
if node == 0 {
func (c *Conn) goDerpConnect(regionID int) {
if regionID == 0 {
return
}
go c.derpWriteChanOfAddr(netip.AddrPortFrom(tailcfg.DerpMagicIPAddr, uint16(node)), key.NodePublic{})
go c.derpWriteChanForRegion(regionID, key.NodePublic{})
}
var (
@ -322,18 +322,15 @@ func bufferedDerpWritesBeforeDrop() int {
return bufferedDerpWrites
}
// derpWriteChanOfAddr returns a DERP client for fake UDP addresses that
// represent DERP servers, creating them as necessary. For real UDP
// addresses, it returns nil.
// derpWriteChanForRegion returns a channel to which to send DERP packet write
// requests. It creates a new DERP connection to regionID if necessary.
//
// If peer is non-zero, it can be used to find an active reverse
// path, without using addr.
func (c *Conn) derpWriteChanOfAddr(addr netip.AddrPort, peer key.NodePublic) chan<- derpWriteRequest {
if addr.Addr() != tailcfg.DerpMagicIPAddr {
return nil
}
regionID := int(addr.Port())
// If peer is non-zero, it can be used to find an active reverse path, without
// using regionID.
//
// It returns nil if the network is down, the Conn is closed, or the regionID is
// not known.
func (c *Conn) derpWriteChanForRegion(regionID int, peer key.NodePublic) chan<- derpWriteRequest {
if c.networkDown() {
return nil
}
@ -347,7 +344,7 @@ func (c *Conn) derpWriteChanOfAddr(addr netip.AddrPort, peer key.NodePublic) cha
return nil
}
if c.privateKey.IsZero() {
c.logf("magicsock: DERP lookup of %v with no private key; ignoring", addr)
c.logf("magicsock: DERP lookup of region %v with no private key; ignoring", regionID)
return nil
}
@ -453,7 +450,7 @@ func (c *Conn) derpWriteChanOfAddr(addr netip.AddrPort, peer key.NodePublic) cha
}()
}
go c.runDerpReader(ctx, addr, dc, wg, startGate)
go c.runDerpReader(ctx, regionID, dc, wg, startGate)
go c.runDerpWriter(ctx, dc, ch, wg, startGate)
go c.derpActiveFunc()
@ -516,7 +513,7 @@ type derpReadResult struct {
// runDerpReader runs in a goroutine for the life of a DERP
// connection, handling received packets.
func (c *Conn) runDerpReader(ctx context.Context, derpFakeAddr netip.AddrPort, dc *derphttp.Client, wg *syncs.WaitGroupChan, startGate <-chan struct{}) {
func (c *Conn) runDerpReader(ctx context.Context, regionID int, dc *derphttp.Client, wg *syncs.WaitGroupChan, startGate <-chan struct{}) {
defer wg.Decr()
defer dc.Close()
@ -527,7 +524,6 @@ func (c *Conn) runDerpReader(ctx context.Context, derpFakeAddr netip.AddrPort, d
}
didCopy := make(chan struct{}, 1)
regionID := int(derpFakeAddr.Port())
res := derpReadResult{regionID: regionID}
var pkt derp.ReceivedPacket
res.copyBuf = func(dst []byte) int {

7
wgengine/magicsock/magicsock.go
View File

@ -7,6 +7,7 @@
import (
"bufio"
"bytes"
"context"
"errors"
"fmt"
@ -1154,7 +1155,8 @@ func (c *Conn) sendAddr(addr netip.AddrPort, pubKey key.NodePublic, b []byte) (s
return c.sendUDP(addr, b)
}
ch := c.derpWriteChanOfAddr(addr, pubKey)
regionID := int(addr.Port())
ch := c.derpWriteChanForRegion(regionID, pubKey)
if ch == nil {
metricSendDERPErrorChan.Add(1)
return false, nil
@ -1165,8 +1167,7 @@ func (c *Conn) sendAddr(addr netip.AddrPort, pubKey key.NodePublic, b []byte) (s
// to derpWriteRequest and waited for derphttp.Client.Send to
// complete, but that's too slow while holding wireguard-go
// internal locks.
pkt := make([]byte, len(b))
copy(pkt, b)
pkt := bytes.Clone(b)
select {
case <-c.donec: