Count IP OutgoingPacketErrors in the NetworkEndpoint methods

Before this change, OutgoingPacketErrors was incremented in the
stack.Route methods. This was going to be a problem once
IPv4/IPv6 WritePackets support fragmentation because Route.WritePackets
might now know how many packets are left after an error occurs.

Test:
  - pkg/tcpip/network/ipv4:ipv4_test
  - pkg/tcpip/network/ipv6:ipv6_test
PiperOrigin-RevId: 334687983

1 files changed, 6 insertions, 15 deletions

diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index 5ade3c832..effe30155 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -211,14 +211,13 @@ func (r *Route) WritePacket(gso *GSO, params NetworkHeaderParams, pkt *PacketBuf
 	// WritePacket takes ownership of pkt, calculate numBytes first.
 	numBytes := pkt.Size()
 
-	err := r.addressEndpoint.NetworkEndpoint().WritePacket(r, gso, params, pkt)
-	if err != nil {
-		r.Stats().IP.OutgoingPacketErrors.Increment()
-	} else {
-		r.nic.stats.Tx.Packets.Increment()
-		r.nic.stats.Tx.Bytes.IncrementBy(uint64(numBytes))
+	if err := r.addressEndpoint.NetworkEndpoint().WritePacket(r, gso, params, pkt); err != nil {
+		return err
 	}
-	return err
+
+	r.nic.stats.Tx.Packets.Increment()
+	r.nic.stats.Tx.Bytes.IncrementBy(uint64(numBytes))
+	return nil
 }
 
 // WritePackets writes a list of n packets through the given route and returns
@@ -228,15 +227,8 @@ func (r *Route) WritePackets(gso *GSO, pkts PacketBufferList, params NetworkHead
 		return 0, tcpip.ErrInvalidEndpointState
 	}
 
-	// WritePackets takes ownership of pkt, calculate length first.
-	numPkts := pkts.Len()
-
 	n, err := r.addressEndpoint.NetworkEndpoint().WritePackets(r, gso, pkts, params)
-	if err != nil {
-		r.Stats().IP.OutgoingPacketErrors.IncrementBy(uint64(numPkts - n))
-	}
 	r.nic.stats.Tx.Packets.IncrementBy(uint64(n))
-
 	writtenBytes := 0
 	for i, pb := 0, pkts.Front(); i < n && pb != nil; i, pb = i+1, pb.Next() {
 		writtenBytes += pb.Size()
@@ -257,7 +249,6 @@ func (r *Route) WriteHeaderIncludedPacket(pkt *PacketBuffer) *tcpip.Error {
 	numBytes := pkt.Data.Size()
 
 	if err := r.addressEndpoint.NetworkEndpoint().WriteHeaderIncludedPacket(r, pkt); err != nil {
-		r.Stats().IP.OutgoingPacketErrors.Increment()
 		return err
 	}
 	r.nic.stats.Tx.Packets.Increment()