Re: [PATCH net-next v4 07/10] ip_tunnel: add drop reasons to the transmit path

[Ido Schimmel]

On Wed, Sep 23, 2026 at 01:15:04AM +0300, Anton Danilov wrote:
> @@ -711,9 +721,15 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
>  
>  		if (!skb_dst(skb)) {
>  			DEV_STATS_INC(dev, tx_fifo_errors);
> +			reason = SKB_DROP_REASON_NO_TX_TARGET;
>  			goto tx_error;
>  		}
>  
> +		/* Only the branches below can derive a destination.  If
> +		 * none of them matches, the payload protocol is not one
> +		 * this tunnel can carry.
> +		 */
> +		reason = SKB_DROP_REASON_UNHANDLED_PROTO;
>  		tun_info = skb_tunnel_info(skb);
>  		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX) &&
>  		    ip_tunnel_info_af(tun_info) == AF_INET &&
> @@ -734,8 +750,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
>  
>  			neigh = dst_neigh_lookup(skb_dst(skb),
>  						 &ipv6_hdr(skb)->daddr);
> -			if (!neigh)
> +			if (!neigh) {
> +				reason = SKB_DROP_REASON_NEIGH_CREATEFAIL;
>  				goto tx_error;
> +			}
>  
>  			addr6 = (const struct in6_addr *)&neigh->primary_key;
>  			addr_type = ipv6_addr_type(addr6);
> @@ -752,8 +770,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
>  				dst = addr6->s6_addr32[3];
>  			}
>  			neigh_release(neigh);
> -			if (do_tx_error_icmp)
> +			if (do_tx_error_icmp) {
> +				reason = SKB_DROP_REASON_NO_TX_TARGET;
>  				goto tx_error_icmp;
> +			}
>  		}
>  #endif
>  		else

Makes more sense:

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 66cb0b86fa79..20b666fcca9a 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -725,11 +725,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 			goto tx_error;
 		}
 
-		/* Only the branches below can derive a destination.  If
-		 * none of them matches, the payload protocol is not one
-		 * this tunnel can carry.
-		 */
-		reason = SKB_DROP_REASON_UNHANDLED_PROTO;
 		tun_info = skb_tunnel_info(skb);
 		if (tun_info && (tun_info->mode & IP_TUNNEL_INFO_TX) &&
 		    ip_tunnel_info_af(tun_info) == AF_INET &&
@@ -776,8 +771,10 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 			}
 		}
 #endif
-		else
+		else {
+			reason = SKB_DROP_REASON_UNHANDLED_PROTO;
 			goto tx_error;
+		}
 
 		if (!md)
 			connected = false;