Improve ebpf connection listener

firewall/interception/ebpf/connection_listener/packet.go

@@ -1,57 +0,0 @@
-//go:build linux
-
-package ebpf
-
-import (
-	"fmt"
-
-	pmpacket "github.com/safing/portmaster/network/packet"
-)
-
-// packet implements the packet.Packet interface.
-type infoPacket struct {
-	pmpacket.Base
-}
-
-// InfoOnly returns whether the packet is informational only and does not
-// represent an actual packet.
-func (pkt *infoPacket) InfoOnly() bool {
-	return true
-}
-
-// LoadPacketData does nothing on Linux, as data is always fully parsed.
-func (pkt *infoPacket) LoadPacketData() error {
-	return fmt.Errorf("can't load data in info only packet")
-}
-
-func (pkt *infoPacket) Accept() error {
-	return nil
-}
-
-func (pkt *infoPacket) Block() error {
-	return nil
-}
-
-func (pkt *infoPacket) Drop() error {
-	return nil
-}
-
-func (pkt *infoPacket) PermanentAccept() error {
-	return pkt.Accept()
-}
-
-func (pkt *infoPacket) PermanentBlock() error {
-	return pkt.Block()
-}
-
-func (pkt *infoPacket) PermanentDrop() error {
-	return nil
-}
-
-func (pkt *infoPacket) RerouteToNameserver() error {
-	return nil
-}
-
-func (pkt *infoPacket) RerouteToTunnel() error {
-	return nil
-}

firewall/interception/ebpf/connection_listener/worker.go

@@ -2,131 +2,124 @@ package ebpf
 
 import (
 	"bytes"
+	"context"
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"net"
+	"sync/atomic"
 
 	"github.com/cilium/ebpf/link"
 	"github.com/cilium/ebpf/ringbuf"
 	"github.com/cilium/ebpf/rlimit"
+
 	"github.com/safing/portbase/log"
 	"github.com/safing/portmaster/network/packet"
 )
 
 //go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc clang -cflags "-O2 -g -Wall -Werror" -type Event bpf ../programs/monitor.c
 
-var stopper chan struct{}
+var ebpfLoadingFailed atomic.Uint32
 
-// StartEBPFWorker starts the ebpf worker.
-func StartEBPFWorker(ch chan packet.Packet) {
-	stopper = make(chan struct{})
+// ConnectionListenerWorker listens to new connections using ebpf.
+func ConnectionListenerWorker(ctx context.Context, packets chan packet.Packet) error {
+	// Allow the current process to lock memory for eBPF resources.
+	if err := rlimit.RemoveMemlock(); err != nil {
+		return fmt.Errorf("ebpf: failed to remove ebpf memlock: %w", err)
+	}
+
+	// Load pre-compiled programs and maps into the kernel.
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		if ebpfLoadingFailed.Add(1) >= 5 {
+			log.Warningf("ebpf: failed to load ebpf object 5 times, giving up with error %s", err)
+			return nil
+		}
+		return fmt.Errorf("ebpf: failed to load ebpf object: %w", err)
+	}
+	defer objs.Close() //nolint:errcheck
+
+	// Create a link to the tcp_connect program.
+	linkTCPConnect, err := link.AttachTracing(link.TracingOptions{
+		Program: objs.bpfPrograms.TcpConnect,
+	})
+	if err != nil {
+		return fmt.Errorf("ebpf: failed to attach to tcp_v4_connect: %w", err)
+	}
+	defer linkTCPConnect.Close() //nolint:errcheck
+
+	// Create a link to the udp_v4_connect program.
+	linkUDPV4, err := link.AttachTracing(link.TracingOptions{
+		Program: objs.bpfPrograms.UdpV4Connect,
+	})
+	if err != nil {
+		return fmt.Errorf("ebpf: failed to attach to udp_v4_connect: %w", err)
+	}
+	defer linkUDPV4.Close() //nolint:errcheck
+
+	// Create a link to the udp_v6_connect program.
+	linkUDPV6, err := link.AttachTracing(link.TracingOptions{
+		Program: objs.bpfPrograms.UdpV6Connect,
+	})
+	if err != nil {
+		return fmt.Errorf("ebpf: failed to attach to udp_v6_connect: %w", err)
+	}
+	defer linkUDPV6.Close() //nolint:errcheck
+
+	// Create new reader to read events.
+	rd, err := ringbuf.NewReader(objs.bpfMaps.PmConnectionEvents)
+	if err != nil {
+		return fmt.Errorf("ebpf: failed to open ring buffer: %w", err)
+	}
+	defer rd.Close() //nolint:errcheck
+
+	// Start watcher to close the reader when the context is canceled.
+	// TODO: Can we put this into a worker?
 	go func() {
-		// Allow the current process to lock memory for eBPF resources.
-		if err := rlimit.RemoveMemlock(); err != nil {
-			log.Errorf("ebpf: failed to remove ebpf memlock: %s", err)
-			return
-		}
-
-		// Load pre-compiled programs and maps into the kernel.
-		objs := bpfObjects{}
-		if err := loadBpfObjects(&objs, nil); err != nil {
-			log.Errorf("ebpf: failed to load ebpf object: %s", err)
-			return
-		}
-		defer objs.Close() //nolint:errcheck
-
-		// Create a link to the tcp_connect program.
-		linkTCPConnect, err := link.AttachTracing(link.TracingOptions{
-			Program: objs.bpfPrograms.TcpConnect,
-		})
-		if err != nil {
-			log.Errorf("ebpf: failed to attach to tcp_v4_connect: %s ", err)
-			return
-		}
-		defer linkTCPConnect.Close() //nolint:errcheck
-
-		// Create a link to the udp_v4_connect program.
-		linkUDPV4, err := link.AttachTracing(link.TracingOptions{
-			Program: objs.bpfPrograms.UdpV4Connect,
-		})
-		if err != nil {
-			log.Errorf("ebpf: failed to attach to udp_v4_connect: %s ", err)
-			return
-		}
-		defer linkUDPV4.Close() //nolint:errcheck
-
-		// Create a link to the udp_v6_connect program.
-		linkUDPV6, err := link.AttachTracing(link.TracingOptions{
-			Program: objs.bpfPrograms.UdpV6Connect,
-		})
-		if err != nil {
-			log.Errorf("ebpf: failed to attach to udp_v6_connect: %s ", err)
-			return
-		}
-		defer linkUDPV6.Close() //nolint:errcheck
-
-		rd, err := ringbuf.NewReader(objs.bpfMaps.PmConnectionEvents)
-		if err != nil {
-			log.Errorf("ebpf: failed to open ring buffer: %s", err)
-			return
-		}
-		defer rd.Close()
-
-		go func() {
-			<-stopper
-
-			if err := rd.Close(); err != nil {
-				log.Errorf("ebpf: failed closing ringbuf reader: %s", err)
-			}
-		}()
-
-		for {
-			// Read next event
-			record, err := rd.Read()
-			if err != nil {
-				if errors.Is(err, ringbuf.ErrClosed) {
-					// Normal return
-					return
-				}
-				log.Errorf("ebpf: failed to read from ring buffer: %s", err)
-				continue
-			}
-
-			var event bpfEvent
-			// Parse the ringbuf event entry into a bpfEvent structure.
-			if err := binary.Read(bytes.NewBuffer(record.RawSample), binary.BigEndian, &event); err != nil {
-				log.Errorf("ebpf: failed to parse ringbuf event: %s", err)
-				continue
-			}
-
-			info := packet.Info{
-				Inbound:  event.Direction == 1,
-				InTunnel: false,
-				Version:  packet.IPVersion(event.IpVersion),
-				Protocol: packet.IPProtocol(event.Protocol),
-				SrcPort:  event.Sport,
-				DstPort:  event.Dport,
-				Src:      convertArrayToIPv4(event.Saddr, packet.IPVersion(event.IpVersion)),
-				Dst:      convertArrayToIPv4(event.Daddr, packet.IPVersion(event.IpVersion)),
-				PID:      int(event.Pid),
-			}
-			if isEventValid(event) {
-				log.Debugf("ebpf: PID: %d conn: %s:%d -> %s:%d %s %s", info.PID, info.LocalIP(), info.LocalPort(), info.RemoteIP(), info.RemotePort(), info.Version.String(), info.Protocol.String())
-
-				p := &infoPacket{}
-				p.SetPacketInfo(info)
-				ch <- p
-			} else {
-				log.Debugf("ebpf: invalid event PID: %d conn: %s:%d -> %s:%d %s %s", info.PID, info.LocalIP(), info.LocalPort(), info.RemoteIP(), info.RemotePort(), info.Version.String(), info.Protocol.String())
-			}
+		<-ctx.Done()
 
+		if err := rd.Close(); err != nil {
+			log.Errorf("ebpf: failed closing ringbuf reader: %s", err)
 		}
 	}()
-}
 
-// StopEBPFWorker stops the ebpf worker.
-func StopEBPFWorker() {
-	close(stopper)
+	for {
+		// Read next event
+		record, err := rd.Read()
+		if err != nil {
+			if errors.Is(err, ringbuf.ErrClosed) {
+				// Normal return
+				return nil
+			}
+			log.Errorf("ebpf: failed to read from ring buffer: %s", err)
+			continue
+		}
+
+		var event bpfEvent
+		// Parse the ringbuf event entry into a bpfEvent structure.
+		if err := binary.Read(bytes.NewBuffer(record.RawSample), binary.BigEndian, &event); err != nil {
+			log.Errorf("ebpf: failed to parse ringbuf event: %s", err)
+			continue
+		}
+
+		pkt := packet.NewInfoPacket(packet.Info{
+			Inbound:  event.Direction == 1,
+			InTunnel: false,
+			Version:  packet.IPVersion(event.IpVersion),
+			Protocol: packet.IPProtocol(event.Protocol),
+			SrcPort:  event.Sport,
+			DstPort:  event.Dport,
+			Src:      convertArrayToIPv4(event.Saddr, packet.IPVersion(event.IpVersion)),
+			Dst:      convertArrayToIPv4(event.Daddr, packet.IPVersion(event.IpVersion)),
+			PID:      int(event.Pid),
+		})
+		if isEventValid(event) {
+			log.Debugf("ebpf: received valid connect event: PID: %d Conn: %s", pkt.Info().PID, pkt)
+			packets <- pkt
+		} else {
+			log.Warningf("ebpf: received invalid connect event: PID: %d Conn: %s", pkt.Info().PID, pkt)
+		}
+	}
 }
 
 // isEventValid checks whether the given bpfEvent is valid or not.
@@ -166,11 +159,11 @@ func convertArrayToIPv4(input [4]uint32, ipVersion packet.IPVersion) net.IP {
 		addressBuf := make([]byte, 4)
 		binary.LittleEndian.PutUint32(addressBuf, input[0])
 		return net.IP(addressBuf)
-	} else {
-		addressBuf := make([]byte, 16)
-		for i := 0; i < 4; i++ {
-			binary.LittleEndian.PutUint32(addressBuf[i*4:i*4+4], input[i])
-		}
-		return net.IP(addressBuf)
 	}
+
+	addressBuf := make([]byte, 16)
+	for i := 0; i < 4; i++ {
+		binary.LittleEndian.PutUint32(addressBuf[i*4:i*4+4], input[i])
+	}
+	return net.IP(addressBuf)
 }

firewall/interception/ebpf/programs/bpf/bpf_tracing.h

@@ -2,7 +2,8 @@
 #ifndef __BPF_TRACING_H__
 #define __BPF_TRACING_H__
 
-#include <bpf/bpf_helpers.h>
+// #include <bpf/bpf_helpers.h>
+#include "bpf_helpers.h"
 
 /* Scan the ARCH passed in from ARCH env variable (see Makefile) */
 #if defined(__TARGET_ARCH_x86)