Re: [PATCH 05/11 net-next v4] ipv6: prepare headers for ipv6_stub removal

[Ido Schimmel]

On Fri, Mar 20, 2026 at 07:55:57PM +0100, Fernando Fernandez Mancera wrote:
> +#if IS_ENABLED(CONFIG_IPV6)
>  int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  		 int (*output)(struct net *, struct sock *, struct sk_buff *));
> +#else
> +static inline int ip6_fragment(struct net *net, struct sock *sk,
> +			       struct sk_buff *skb,
> +			       int (*output)(struct net *, struct sock *,
> +					     struct sk_buff *))
> +{
> +	kfree_skb(skb);
> +	return -EAFNOSUPPORT;
> +}
> +#endif

[...]

> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> index 8e2a6b28cea7..79f7ee93ceff 100644
> --- a/net/ipv6/ip6_output.c
> +++ b/net/ipv6/ip6_output.c
> @@ -873,6 +873,8 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  	__be32 frag_id;
>  	u8 *prevhdr, nexthdr = 0;
>  
> +	if (!ipv6_mod_enabled())
> +		return -EAFNOSUPPORT;

Free the skb?

>  	err = ip6_find_1stfragopt(skb, &prevhdr);
>  	if (err < 0)
>  		goto fail;
> @@ -1045,6 +1047,7 @@ int ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
>  	kfree_skb(skb);
>  	return err;
>  }
> +EXPORT_SYMBOL_GPL(ip6_fragment);