Commit d7f57118 authored by Cong Wang's avatar Cong Wang Committed by Alexei Starovoitov
Browse files

udp: Implement ->read_sock() for sockmap 



This is similar to tcp_read_sock(), except we do not need
to worry about connections, we just need to retrieve skb
from UDP receive queue.

Note, the return value of ->read_sock() is unused in
sk_psock_verdict_data_ready(), and UDP still does not
support splice() due to lack of ->splice_read(), so users
can not reach udp_read_sock() directly.

Signed-off-by: default avatarCong Wang <cong.wang@bytedance.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20210331023237.41094-12-xiyou.wangcong@gmail.com
parent 8a59f9d1

include/net/udp.h

+2 −0
Original line number Diff line number Diff line
@@ -329,6 +329,8 @@ 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()

net/ipv4/af_inet.c

+1 −0
Original line number Diff line number Diff line
@@ -1070,6 +1070,7 @@ const struct proto_ops inet_dgram_ops = { 
	.setsockopt	   = sock_common_setsockopt,

	.getsockopt	   = sock_common_getsockopt,

	.sendmsg	   = inet_sendmsg,

	.read_sock	   = udp_read_sock,

	.recvmsg	   = inet_recvmsg,

	.mmap		   = sock_no_mmap,

	.sendpage	   = inet_sendpage,

net/ipv4/udp.c

+29 −0
Original line number Diff line number Diff line
@@ -1782,6 +1782,35 @@ 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)

{

	int copied = 0;



	while (1) {

		struct sk_buff *skb;

		int err, used;



		skb = skb_recv_udp(sk, 0, 1, &err);

		if (!skb)

			return err;

		used = recv_actor(desc, skb, 0, skb->len);

		if (used <= 0) {

			if (!copied)

				copied = used;

			break;

		} else if (used <= skb->len) {

			copied += used;

		}



		if (!desc->count)

			break;

	}



	return copied;

}

EXPORT_SYMBOL(udp_read_sock);



/*

 * 	This should be easy, if there is something there we

 * 	return it, otherwise we block.

net/ipv6/af_inet6.c

+1 −0
Original line number Diff line number Diff line
@@ -714,6 +714,7 @@ const struct proto_ops inet6_dgram_ops = { 
	.getsockopt	   = sock_common_getsockopt,	/* ok		*/

	.sendmsg	   = inet6_sendmsg,		/* retpoline's sake */

	.recvmsg	   = inet6_recvmsg,		/* retpoline's sake */

	.read_sock	   = udp_read_sock,

	.mmap		   = sock_no_mmap,

	.sendpage	   = sock_no_sendpage,

	.set_peek_off	   = sk_set_peek_off,