On Sun, Mar 21, 2021 at 1:01 PM Paolo Abeni <pab...@redhat.com> wrote:
>
> Currently the UDP protocol delivers GSO_FRAGLIST packets to
> the sockets without the expected segmentation.
>
> This change addresses the issue introducing and maintaining
> a per socket bitmask of GSO types requiring segmentation.
> Enabling GSO removes SKB_GSO_UDP_L4 from such mask, while
> GSO_FRAGLIST packets are never accepted
>
> Note: this also updates the 'unused' field size to really
> fit the otherwise existing hole. It's size become incorrect
> after commit bec1f6f69736 ("udp: generate gso with UDP_SEGMENT").
>
> Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
> Signed-off-by: Paolo Abeni <pab...@redhat.com>
> ---
> include/linux/udp.h | 10 ++++++----
> net/ipv4/udp.c | 12 +++++++++++-
> 2 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/udp.h b/include/linux/udp.h
> index aa84597bdc33c..6da342f15f351 100644
> --- a/include/linux/udp.h
> +++ b/include/linux/udp.h
> @@ -51,7 +51,7 @@ struct udp_sock {
> * different encapsulation layer set
> * this
> */
> - gro_enabled:1; /* Can accept GRO packets */
> + gro_enabled:1; /* Request GRO aggregation */
unnecessary comment change?
> /*
> * Following member retains the information to create a UDP header
> * when the socket is uncorked.
> @@ -68,7 +68,10 @@ struct udp_sock {
> #define UDPLITE_SEND_CC 0x2 /* set via udplite setsockopt
> */
> #define UDPLITE_RECV_CC 0x4 /* set via udplite setsocktopt
> */
> __u8 pcflag; /* marks socket as UDP-Lite if > 0
> */
> - __u8 unused[3];
> + __u8 unused[1];
> + unsigned int unexpected_gso;/* GSO types this socket can't accept,
> + * any of SKB_GSO_UDP_L4 or
> SKB_GSO_FRAGLIST
> + */
An extra unsigned int for this seems overkill.
Current sockets that support SKB_GSO_UDP_L4 implicitly also support
SKB_GSO_FRAGLIST. This patch makes explicit that the second is not
supported..
> /*
> * For encapsulation sockets.
> */
> @@ -131,8 +134,7 @@ static inline void udp_cmsg_recv(struct msghdr *msg,
> struct sock *sk,
>
> static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
> {
> - return !udp_sk(sk)->gro_enabled && skb_is_gso(skb) &&
> - skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4;
> + return skb_is_gso(skb) && skb_shinfo(skb)->gso_type &
> udp_sk(sk)->unexpected_gso;
.. just update this function as follows ?
- return !udp_sk(sk)->gro_enabled && skb_is_gso(skb) &&
- skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4;
+ return skb_is_gso(skb) &&
+ (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST ||
!udp_sk(sk)->gro_enabled)
where the latter is shorthand for
(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 && !udp_sk(sk)->gro_enabled)
but the are the only two GSO types that could arrive here.
