cloudflared-mirror/ingress/origin_icmp_proxy.go

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package ingress
import (
"context"
"fmt"
"net/netip"
"time"
"github.com/rs/zerolog"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
"github.com/cloudflare/cloudflared/packet"
)
const (
// funnelIdleTimeout controls how long to wait to close a funnel without send/return
funnelIdleTimeout = time.Second * 10
mtu = 1500
// icmpRequestTimeoutMs controls how long to wait for a reply
icmpRequestTimeoutMs = 1000
)
var (
errPacketNil = fmt.Errorf("packet is nil")
)
type icmpRouter struct {
ipv4Proxy *icmpProxy
ipv6Proxy *icmpProxy
}
// NewICMPRouter doesn't return an error if either ipv4 proxy or ipv6 proxy can be created. The machine might only
// support one of them
func NewICMPRouter(logger *zerolog.Logger) (*icmpRouter, error) {
// TODO: TUN-6741: don't bind to all interface
ipv4Proxy, ipv4Err := newICMPProxy(netip.IPv4Unspecified(), logger, funnelIdleTimeout)
ipv6Proxy, ipv6Err := newICMPProxy(netip.IPv6Unspecified(), logger, funnelIdleTimeout)
if ipv4Err != nil && ipv6Err != nil {
return nil, fmt.Errorf("cannot create ICMPv4 proxy: %v nor ICMPv6 proxy: %v", ipv4Err, ipv6Err)
}
if ipv4Err != nil {
logger.Debug().Err(ipv4Err).Msg("failed to create ICMPv4 proxy, only ICMPv6 proxy is created")
ipv4Proxy = nil
}
if ipv6Err != nil {
logger.Debug().Err(ipv6Err).Msg("failed to create ICMPv6 proxy, only ICMPv4 proxy is created")
ipv6Proxy = nil
}
return &icmpRouter{
ipv4Proxy: ipv4Proxy,
ipv6Proxy: ipv6Proxy,
}, nil
}
func (ir *icmpRouter) Serve(ctx context.Context) error {
if ir.ipv4Proxy != nil && ir.ipv6Proxy != nil {
errC := make(chan error, 2)
go func() {
errC <- ir.ipv4Proxy.Serve(ctx)
}()
go func() {
errC <- ir.ipv6Proxy.Serve(ctx)
}()
return <-errC
}
if ir.ipv4Proxy != nil {
return ir.ipv4Proxy.Serve(ctx)
}
if ir.ipv6Proxy != nil {
return ir.ipv6Proxy.Serve(ctx)
}
return fmt.Errorf("ICMPv4 proxy and ICMPv6 proxy are both nil")
}
func (ir *icmpRouter) Request(pk *packet.ICMP, responder packet.FunnelUniPipe) error {
if pk.Dst.Is4() {
if ir.ipv4Proxy != nil {
return ir.ipv4Proxy.Request(pk, responder)
}
return fmt.Errorf("ICMPv4 proxy was not instantiated")
}
if ir.ipv6Proxy != nil {
return ir.ipv6Proxy.Request(pk, responder)
}
return fmt.Errorf("ICMPv6 proxy was not instantiated")
}
func getICMPEcho(msg *icmp.Message) (*icmp.Echo, error) {
echo, ok := msg.Body.(*icmp.Echo)
if !ok {
return nil, fmt.Errorf("expect ICMP echo, got %s", msg.Type)
}
return echo, nil
}
func isEchoReply(msg *icmp.Message) bool {
return msg.Type == ipv4.ICMPTypeEchoReply || msg.Type == ipv6.ICMPTypeEchoReply
}