Commit 1f5be6b3 authored by Cong Wang's avatar Cong Wang Committed by Alexei Starovoitov
Browse files

udp: Implement udp_bpf_recvmsg() for sockmap 



We have to implement udp_bpf_recvmsg() to replace the ->recvmsg()
to retrieve skmsg from ingress_msg.

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/20210331023237.41094-14-xiyou.wangcong@gmail.com
parent 2bc793e3

net/ipv4/udp_bpf.c

+63 −1
Original line number Diff line number Diff line
@@ -4,6 +4,68 @@ 
#include <linux/skmsg.h>

#include <net/sock.h>

#include <net/udp.h>

#include <net/inet_common.h>



#include "udp_impl.h"



static struct proto *udpv6_prot_saved __read_mostly;



static int sk_udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,

			  int noblock, int flags, int *addr_len)

{

#if IS_ENABLED(CONFIG_IPV6)

	if (sk->sk_family == AF_INET6)

		return udpv6_prot_saved->recvmsg(sk, msg, len, noblock, flags,

						 addr_len);

#endif

	return udp_prot.recvmsg(sk, msg, len, noblock, flags, addr_len);

}



static int udp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,

			   int nonblock, int flags, int *addr_len)

{

	struct sk_psock *psock;

	int copied, ret;



	if (unlikely(flags & MSG_ERRQUEUE))

		return inet_recv_error(sk, msg, len, addr_len);



	psock = sk_psock_get(sk);

	if (unlikely(!psock))

		return sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);



	lock_sock(sk);

	if (sk_psock_queue_empty(psock)) {

		ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);

		goto out;

	}



msg_bytes_ready:

	copied = sk_msg_recvmsg(sk, psock, msg, len, flags);

	if (!copied) {

		int data, err = 0;

		long timeo;



		timeo = sock_rcvtimeo(sk, nonblock);

		data = sk_msg_wait_data(sk, psock, flags, timeo, &err);

		if (data) {

			if (!sk_psock_queue_empty(psock))

				goto msg_bytes_ready;

			ret = sk_udp_recvmsg(sk, msg, len, nonblock, flags, addr_len);

			goto out;

		}

		if (err) {

			ret = err;

			goto out;

		}

		copied = -EAGAIN;

	}

	ret = copied;

out:

	release_sock(sk);

	sk_psock_put(sk, psock);

	return ret;

}



enum {

	UDP_BPF_IPV4,
@@ -11,7 +73,6 @@ enum { 
	UDP_BPF_NUM_PROTS,

};



static struct proto *udpv6_prot_saved __read_mostly;

static DEFINE_SPINLOCK(udpv6_prot_lock);

static struct proto udp_bpf_prots[UDP_BPF_NUM_PROTS];
@@ -20,6 +81,7 @@ static void udp_bpf_rebuild_protos(struct proto *prot, const struct proto *base) 
	*prot        = *base;

	prot->unhash = sock_map_unhash;

	prot->close  = sock_map_close;

	prot->recvmsg = udp_bpf_recvmsg;

}



static void udp_bpf_check_v6_needs_rebuild(struct proto *ops)