diff mbox series

[bpf-next,v2,1/9] af_unix: implement ->read_sock() for sockmap

Message ID 20210419175603.19378-2-xiyou.wangcong@gmail.com
State Superseded
Headers show
Series sockmap: add sockmap support to Unix datagram socket | expand

Commit Message

Cong Wang April 19, 2021, 5:55 p.m. UTC 
From: Cong Wang <cong.wang@bytedance.com>

Implement ->read_sock() for AF_UNIX datagram socket, it is
pretty much similar to udp_read_sock().

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jakub Sitnicki <jakub@cloudflare.com>
Cc: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 net/unix/af_unix.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
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Patch

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 5a31307ceb76..966359b64a56 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -661,6 +661,7 @@  static ssize_t unix_stream_splice_read(struct socket *,  loff_t *ppos,
 				       unsigned int flags);
 static int unix_dgram_sendmsg(struct socket *, struct msghdr *, size_t);
 static int unix_dgram_recvmsg(struct socket *, struct msghdr *, size_t, int);
+int unix_read_sock(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor);
 static int unix_dgram_connect(struct socket *, struct sockaddr *,
 			      int, int);
 static int unix_seqpacket_sendmsg(struct socket *, struct msghdr *, size_t);
@@ -738,6 +739,7 @@  static const struct proto_ops unix_dgram_ops = {
 	.listen =	sock_no_listen,
 	.shutdown =	unix_shutdown,
 	.sendmsg =	unix_dgram_sendmsg,
+	.read_sock =	unix_read_sock,
 	.recvmsg =	unix_dgram_recvmsg,
 	.mmap =		sock_no_mmap,
 	.sendpage =	sock_no_sendpage,
@@ -2183,6 +2185,41 @@  static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 	return err;
 }
 
+int unix_read_sock(struct sock *sk, read_descriptor_t *desc,
+		   sk_read_actor_t recv_actor)
+{
+	int copied = 0;
+
+	while (1) {
+		struct unix_sock *u = unix_sk(sk);
+		struct sk_buff *skb;
+		int used, err;
+
+		mutex_lock(&u->iolock);
+		skb = skb_recv_datagram(sk, 0, 1, &err);
+		if (!skb) {
+			mutex_unlock(&u->iolock);
+			return err;
+		}
+
+		used = recv_actor(desc, skb, 0, skb->len);
+		if (used <= 0) {
+			if (!copied)
+				copied = used;
+			mutex_unlock(&u->iolock);
+			break;
+		} else if (used <= skb->len) {
+			copied += used;
+		}
+		mutex_unlock(&u->iolock);
+
+		if (!desc->count)
+			break;
+	}
+
+	return copied;
+}
+
 /*
  *	Sleep until more data has arrived. But check for races..
  */