dot: use core.ConnPool

Author: ignoramous

intra/dns53/dot.go

@@ -25,6 +25,8 @@ import (
 	"golang.org/x/net/context"
 )
 
+const usepool = true
+
 type dot struct {
 	ctx           context.Context
 	done          context.CancelFunc
@@ -37,6 +39,7 @@ type dot struct {
 	c             *dns.Client
 	c3            *dns.Client // with ech
 	rd            *protect.RDial
+	pool          *core.MultConnPool[uintptr]
 	proxies       ipn.Proxies // may be nil
 	relay         ipn.Proxy   // may be nil
 	est           core.P2QuantileEstimator
@@ -93,6 +96,7 @@ func NewTLSTransport(ctx context.Context, id, rawurl string, addrs []string, px
 		proxies:       px,
 		rd:            rd,
 		relay:         relay,
+		pool:          core.NewMultConnPool[uintptr](ctx),
 		est:           core.NewP50Estimator(ctx),
 	}
 	ech := t.ech()
@@ -153,13 +157,19 @@ func (t *dot) doQuery(pid string, q *dns.Msg) (response *dns.Msg, elapsed time.D
 	return
 }
 
-func (t *dot) tlsdial(rd protect.RDialer) (_ *dns.Conn, err error) {
+func (t *dot) tlsdial(rd protect.RDialer) (_ *dns.Conn, who uintptr, err error) {
+	who = rd.Handle()
+	if c := t.fromPool(who); c != nil {
+		return c, who, nil
+	}
+
+	var usingech bool
 	var c net.Conn = nil // dot is always tcp
 	addr := t.addr       // t.addr may be ip or hostname
 	if t.c3 != nil {     // may be nil if ech is not available
 		cfg := t.c3.TLSConfig // don't clone; may be modified by dialers.DialWithTls
 		c, err = dialers.DialWithTls(rd, cfg, "tcp", addr)
-		log.W("dot: tlsdial: (%s) ech; err? %v", t.id, err)
+		usingech = true
 	}
 	if c == nil && core.IsNil(c) { // no ech or ech failed
 		cfg := t.c.TLSConfig
@@ -169,34 +179,64 @@ func (t *dot) tlsdial(rd protect.RDialer) (_ *dns.Conn, err error) {
 		_ = c.SetDeadline(time.Now().Add(dottimeout))
 		// todo: higher timeout for if using proxy dialer
 		// _ = c.SetDeadline(time.Now().Add(dottimeout * 2))
-		return &dns.Conn{Conn: c, UDPSize: t.c.UDPSize}, err
+		return &dns.Conn{Conn: c, UDPSize: t.c.UDPSize}, who, err
 	} else {
 		if err == nil {
-			log.W("dot: tlsdial: (%s) nil conn/err for %s", t.id, addr)
 			err = errNoNet
 		}
+		log.W("dot: tlsdial: (%s) nil conn/err for %s, ech? %t; err? %v",
+			t.id, addr, usingech, err)
 	}
-	return nil, err
+	return nil, who, err
 }
 
-func (t *dot) pxdial(pid string) (*dns.Conn, error) {
+func (t *dot) pxdial(pid string) (*dns.Conn, uintptr, error) {
 	var px ipn.Proxy
 	if t.relay != nil { // relay takes precedence
 		px = t.relay
 	} else if t.proxies != nil { // use proxy, if specified
 		var err error
 		if px, err = t.proxies.ProxyFor(pid); err != nil {
-			return nil, err
+			return nil, core.Nobody, err
 		}
 	}
 	if px == nil {
-		return nil, dnsx.ErrNoProxyProvider
+		return nil, core.Nobody, dnsx.ErrNoProxyProvider
 	}
+	pid = px.ID()
 	log.V("dot: pxdial: (%s) using relay/proxy %s at %s",
-		t.id, px.ID(), px.GetAddr())
+		t.id, pid, px.GetAddr())
+
 	return t.tlsdial(px.Dialer())
 }
 
+func (t *dot) toPool(id uintptr, c *dns.Conn) {
+	if !usepool || id == core.Nobody {
+		clos(c)
+		return
+	}
+	ok := t.pool.Put(id, c)
+	log.V("dot: pool: (%s) put for %v; ok? %t", t.id, id, ok)
+}
+
+func (t *dot) fromPool(id uintptr) (c *dns.Conn) {
+	if !usepool || id == core.Nobody {
+		return
+	}
+
+	pooled := t.pool.Get(id)
+	if pooled == nil || core.IsNil(pooled) {
+		return
+	}
+	var ok bool
+	if c, ok = pooled.(*dns.Conn); !ok { // unlikely
+		clos(pooled)
+		return
+	}
+	log.V("dot: pool: (%s) got conn from %v; %d", t.id, id)
+	return
+}
+
 func clos(c net.Conn) {
 	core.CloseConn(c)
 }
@@ -210,18 +250,17 @@ func (t *dot) sendRequest(pid string, q *dns.Msg) (ans *dns.Msg, elapsed time.Du
 	}
 
 	var conn *dns.Conn
+	var who uintptr
 	userelay := t.relay != nil
 	useproxy := len(pid) != 0 // pid == dnsx.NetNoProxy => ipn.Base
 	if useproxy || userelay {
-		conn, err = t.pxdial(pid)
+		conn, who, err = t.pxdial(pid)
 	} else { // ref dns.Client.Dial
-		conn, err = t.tlsdial(t.rd)
+		conn, who, err = t.tlsdial(t.rd)
 	}
 
 	if err == nil {
-		// FIXME: conn pooling using t.c.Dial + ExchangeWithConn
 		ans, elapsed, err = t.c.ExchangeWithConn(q, conn)
-		clos(conn)
 	} // fallthrough
 
 	raddr := remoteAddrIfAny(conn)
@@ -232,6 +271,7 @@ func (t *dot) sendRequest(pid string, q *dns.Msg) (ans *dns.Msg, elapsed time.Du
 			t.id, xdns.Size(q), xdns.EDNS0PadLen(q), err, ok, t.host, raddr)
 		qerr = dnsx.NewSendFailedQueryError(err)
 	} else {
+		t.toPool(who, conn) // or close
 		dialers.Confirm2(t.host, raddr)
 	}
 	return
@@ -321,3 +361,10 @@ func url2addr(url string) string {
 	}
 	return url
 }
+
+func logev(err error) log.LogFn {
+	if err != nil {
+		return log.E
+	}
+	return log.V
+}