Re: [RFC PATCH v3 06/10] udp: cope with UDP GRO packet misdirection

[Paolo Abeni <pabeni@redhat.com>]

On Tue, 2018-10-30 at 18:24 +0100, Paolo Abeni wrote:
> --- a/include/net/udp.h
> +++ b/include/net/udp.h
> @@ -406,17 +406,24 @@ static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
>  } while(0)
>  
>  #if IS_ENABLED(CONFIG_IPV6)
> -#define __UDPX_INC_STATS(sk, field)					\
> -do {									\
> -	if ((sk)->sk_family == AF_INET)					\
> -		__UDP_INC_STATS(sock_net(sk), field, 0);		\
> -	else								\
> -		__UDP6_INC_STATS(sock_net(sk), field, 0);		\
> -} while (0)
> +#define __UDPX_MIB(sk, ipv4)						\
> +({									\
> +	ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics :	\
> +				 sock_net(sk)->mib.udp_statistics) :	\
> +		(IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 :	\
> +				 sock_net(sk)->mib.udp_stats_in6);	\
> +})
>  #else
> -#define __UDPX_INC_STATS(sk, field) __UDP_INC_STATS(sock_net(sk), field, 0)
> +#define __UDPX_MIB(sk, ipv4)						\
> +({									\
> +	IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics :		\
> +			 sock_net(sk)->mib.udp_statistics;		\
> +})
>  #endif
>  
> +#define __UDPX_INC_STATS(sk, field) \
> +	__SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET, field)
> +

This is broken (complains only if CONFIG_AF_RXRPC is set), will fix in
next iteration (thanks kbuildbot).

But I'd prefer to keep the above helper: it can be used in a follow-up
patch to cleanup a bit udp6_recvmsg().

>  #ifdef CONFIG_PROC_FS
>  struct udp_seq_afinfo {
>  	sa_family_t			family;
> @@ -450,4 +457,32 @@ DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
>  void udpv6_encap_enable(void);
>  #endif
>  
> +static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
> +					      struct sk_buff *skb)
> +{
> +	bool ipv4 = skb->protocol == htons(ETH_P_IP);

And this cause a compile warning when # CONFIG_IPV6 is not set, I will
fix in the next iteration (again thanks kbuildbot)

Cheers,

Paolo