fix newstrategy test in geneva_test.go, fix linter errors

actions/actions.go

@@ -4,17 +4,21 @@
 package actions
 
 import (
+	"errors"
 	"fmt"
 
+	"github.com/google/gopacket"
+
 	"github.com/getlantern/geneva/internal"
 	"github.com/getlantern/geneva/internal/scanner"
 	"github.com/getlantern/geneva/triggers"
-	"github.com/google/gopacket"
 
 	// gopacket best practice says import this, too.
 	_ "github.com/google/gopacket/layers"
 )
 
+var ErrInvalidAction = errors.New("invalid action")
+
 // ActionTree represents a Geneva (trigger, action) pair.
 //
 // Technically, Geneva uses the term "action tree" to refer to the tree of actions in the tuple
@@ -122,5 +126,5 @@ func ParseAction(s *scanner.Scanner) (Action, error) {
 		return DefaultSendAction, nil
 	}
 
-	return nil, fmt.Errorf("invalid action at %d", s.Pos())
+	return nil, fmt.Errorf("%w at %d", ErrInvalidAction, s.Pos())
 }

actions/duplicate_action.go

@@ -4,9 +4,10 @@ import (
 	"errors"
 	"fmt"
 
+	"github.com/google/gopacket"
+
 	"github.com/getlantern/geneva/internal"
 	"github.com/getlantern/geneva/internal/scanner"
-	"github.com/google/gopacket"
 )
 
 // DuplicateAction is a Geneva action that duplicates a packet and applies separate action trees to
@@ -114,6 +115,10 @@ func ParseDuplicateAction(s *scanner.Scanner) (Action, error) {
 	}
 
 	if action.Left, err = ParseAction(s); err != nil {
+		if !errors.Is(err, ErrInvalidAction) {
+			return nil, err
+		}
+
 		if c, err2 := s.Peek(); err2 == nil && c == ',' {
 			action.Left = &SendAction{}
 		} else {

actions/fragment_packet.go

@@ -145,7 +145,9 @@ func fragmentTCPSegment(packet gopacket.Packet, fragSize int) ([]gopacket.Packet
 	ipHdrLen := uint16(ipv4Buf[0]&0x0f) * 4
 
 	first := gopacket.NewPacket(buf, packet.Layers()[0].LayerType(), gopacket.NoCopy)
-	updateChecksums(first)
+	if err := updateChecksums(first); err != nil {
+		return nil, err
+	}
 
 	// create the second fragment.
 	f2Len := headersLen + tcpPayloadLen - fragSize
@@ -166,7 +168,9 @@ func fragmentTCPSegment(packet gopacket.Packet, fragSize int) ([]gopacket.Packet
 	binary.BigEndian.PutUint32(tcp[4:], seqNum)
 
 	second := gopacket.NewPacket(buf, packet.Layers()[0].LayerType(), gopacket.NoCopy)
-	updateChecksums(second)
+	if err := updateChecksums(second); err != nil {
+		return nil, err
+	}
 
 	return []gopacket.Packet{first, second}, nil
 }
@@ -260,14 +264,16 @@ func FragmentIPPacket(packet gopacket.Packet, fragSize int) ([]gopacket.Packet,
 	return []gopacket.Packet{first, second}, nil
 }
 
-func updateChecksums(packet gopacket.Packet) {
-	if ipv4 := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4); ipv4 != nil {
+func updateChecksums(packet gopacket.Packet) error {
+	if ipv4, _ := packet.Layer(layers.LayerTypeIPv4).(*layers.IPv4); ipv4 != nil {
 		common.UpdateIPv4Checksum(ipv4)
 	}
 
-	if tcp := packet.Layer(layers.LayerTypeTCP).(*layers.TCP); tcp != nil {
-		common.UpdateTCPChecksum(tcp)
+	if tcp, _ := packet.Layer(layers.LayerTypeTCP).(*layers.TCP); tcp != nil {
+		return common.UpdateTCPChecksum(tcp)
 	}
+
+	return nil
 }
 
 // VerifyIPv4Checksum verifies whether an IPv4 header's checksum field is correct.
@@ -375,6 +381,10 @@ func ParseFragmentAction(s *scanner.Scanner) (Action, error) {
 	}
 
 	if action.FirstFragmentAction, err = ParseAction(s); err != nil {
+		if !errors.Is(err, ErrInvalidAction) {
+			return nil, err
+		}
+
 		if c, err2 := s.Peek(); err2 == nil && c == ',' {
 			action.FirstFragmentAction = &SendAction{}
 		} else {