On Wed, 3 Feb 2021 at 04:17, Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:
>
> From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
>
> Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
> Cc: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
> ---
> include/net/udp.h | 2 ++
> net/ipv4/af_inet.c | 1 +
> net/ipv4/udp.c | 34 ++++++++++++++++++++++++++++++++++
> 3 files changed, 37 insertions(+)
>
> diff --git a/include/net/udp.h b/include/net/udp.h
> index 13f9354dbd3e..b6b75cabf4e4 100644
> --- a/include/net/udp.h
> +++ b/include/net/udp.h
> @@ -327,6 +327,8 @@ struct sock *__udp6_lib_lookup(struct net *net,
> struct sk_buff *skb);
> struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
> __be16 sport, __be16 dport);
> +int udp_read_sock(struct sock *sk, read_descriptor_t *desc,
> + sk_read_actor_t recv_actor);
>
> /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
> * possibly multiple cache miss on dequeue()
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index d184d9379a92..4a4c6d3d2786 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -1072,6 +1072,7 @@ const struct proto_ops inet_dgram_ops = {
> .getsockopt = sock_common_getsockopt,
> .sendmsg = inet_sendmsg,
> .sendmsg_locked = udp_sendmsg_locked,
> + .read_sock = udp_read_sock,
> .recvmsg = inet_recvmsg,
> .mmap = sock_no_mmap,
> .sendpage = inet_sendpage,
> diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> index 635e1e8b2968..6dffbcec0b51 100644
> --- a/net/ipv4/udp.c
> +++ b/net/ipv4/udp.c
> @@ -1792,6 +1792,40 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
> }
> EXPORT_SYMBOL(__skb_recv_udp);
>
> +int udp_read_sock(struct sock *sk, read_descriptor_t *desc,
> + sk_read_actor_t recv_actor)
> +{
> + struct sk_buff *skb;
> + int copied = 0, err;
> +
> + while (1) {
> + int offset = 0;
> +
> + skb = __skb_recv_udp(sk, 0, 1, &offset, &err);
Seems like err isn't used outside of the loop, is that on purpose? If
yes, how about moving the declaration of err to be with offset. Maybe
rename to ignored?
> + if (!skb)
> + break;
> + if (offset < skb->len) {
> + int used;
> + size_t len;
> +
> + len = skb->len - offset;
> + used = recv_actor(desc, skb, offset, len);
> + if (used <= 0) {
> + if (!copied)
> + copied = used;
> + break;
> + } else if (used <= len) {
In which case can used be > len?
> + copied += used;
> + offset += used;
> + }
> + }
> + if (!desc->count)
> + break;
> + }
> +
> + return copied;
> +}
> +
> /*
> * This should be easy, if there is something there we
> * return it, otherwise we block.
> --
> 2.25.1
>
--
Lorenz Bauer | Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK
www.cloudflare.com
