add x/xnet experimental package

x/xnet/stack-retrying.go

@@ -0,0 +1,98 @@
+package xnet
+
+import (
+	"errors"
+	"net/netip"
+	"time"
+
+	"github.com/soypat/lneto/tcp"
+)
+
+func (s *StackAsync) StackRetrying() StackRetrying {
+	return StackRetrying{
+		block: s.StackBlocking(),
+	}
+}
+
+var (
+	errRetriesExceeded = errors.New("cywnet: retries exceeded")
+)
+
+type StackRetrying struct {
+	block StackBlocking
+}
+
+func (s StackRetrying) DoDHCPv4(reqAddr [4]byte, timeout time.Duration, retries int) (results *DHCPResults, err error) {
+	expectEnd := time.Now().Add(timeout * time.Duration(retries))
+	for i := 0; i < retries; i++ {
+		if i > 0 {
+			println("Retrying DHCP")
+		}
+		results, err = s.block.DoDHCPv4(reqAddr, timeout)
+		if err == nil {
+			return results, nil
+		}
+	}
+	if time.Now().Before(expectEnd) {
+		return nil, err
+	}
+	return nil, errRetriesExceeded
+}
+
+func (s StackRetrying) DoNTP(ntpHost netip.Addr, timeout time.Duration, retries int) (offset time.Duration, err error) {
+	expectEnd := time.Now().Add(timeout * time.Duration(retries))
+	for i := 0; i < retries; i++ {
+		if i > 0 {
+			println("Retrying DHCP")
+		}
+		offset, err = s.block.DoNTP(ntpHost, timeout)
+		if err == nil {
+			return offset, nil
+		}
+	}
+	if time.Now().Before(expectEnd) {
+		return -1, err
+	}
+	return -1, errRetriesExceeded
+}
+func (s StackRetrying) DoLookupIP(host string, timeout time.Duration, retries int) (addrs []netip.Addr, err error) {
+	expectEnd := time.Now().Add(timeout * time.Duration(retries))
+	for i := 0; i < retries; i++ {
+		addrs, err = s.block.DoLookupIP(host, timeout)
+		if err == nil {
+			return addrs, nil
+		}
+	}
+	if time.Now().Before(expectEnd) {
+		return addrs, err
+	}
+	return nil, errRetriesExceeded
+}
+
+func (s StackRetrying) DoResolveHardwareAddress6(addr netip.Addr, timeout time.Duration, retries int) (hw [6]byte, err error) {
+	expectEnd := time.Now().Add(timeout * time.Duration(retries))
+	for i := 0; i < retries; i++ {
+		hw, err = s.block.DoResolveHardwareAddress6(addr, timeout)
+		if err == nil {
+			return hw, nil
+		}
+	}
+	if time.Now().Before(expectEnd) {
+		return hw, err
+	}
+	return hw, errRetriesExceeded
+}
+
+func (s StackRetrying) DoDialTCP(localPort uint16, addrp netip.AddrPort, timeout time.Duration, retries int) (conn *tcp.Conn, err error) {
+	expectEnd := time.Now().Add(timeout * time.Duration(retries))
+	for i := 0; i < retries; i++ {
+		conn, err = s.block.DoDialTCP(localPort, addrp, timeout)
+		if err == nil {
+			return conn, nil
+		}
+	}
+	if time.Now().Before(expectEnd) {
+		return conn, err
+	}
+	return nil, errRetriesExceeded
+}