From 04919bed948dc22a0032a9da867b7dcb8aece4ca Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Wed, 15 Jun 2022 09:20:11 -0700 Subject: [PATCH] tcp: Introduce tcp_read_skb() This patch inroduces tcp_read_skb() based on tcp_read_sock(), a preparation for the next patch which actually introduces a new sock ops. TCP is special here, because it has tcp_read_sock() which is mainly used by splice(). tcp_read_sock() supports partial read and arbitrary offset, neither of them is needed for sockmap. Signed-off-by: Cong Wang Signed-off-by: Daniel Borkmann Reviewed-by: Eric Dumazet Reviewed-by: John Fastabend Link: https://lore.kernel.org/bpf/20220615162014.89193-2-xiyou.wangcong@gmail.com --- include/net/tcp.h | 2 ++ net/ipv4/tcp.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/include/net/tcp.h b/include/net/tcp.h index c21a9b516f1ed2..7547d90fbb57c3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -672,6 +672,8 @@ void tcp_get_info(struct sock *, struct tcp_info *); /* Read 'sendfile()'-style from a TCP socket */ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, sk_read_actor_t recv_actor); +int tcp_read_skb(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor); void tcp_initialize_rcv_mss(struct sock *sk); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f7309452bdcec0..124f384f869584 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1734,6 +1734,53 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, } EXPORT_SYMBOL(tcp_read_sock); +int tcp_read_skb(struct sock *sk, read_descriptor_t *desc, + sk_read_actor_t recv_actor) +{ + struct tcp_sock *tp = tcp_sk(sk); + u32 seq = tp->copied_seq; + struct sk_buff *skb; + int copied = 0; + u32 offset; + + if (sk->sk_state == TCP_LISTEN) + return -ENOTCONN; + + while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) { + int used; + + __skb_unlink(skb, &sk->sk_receive_queue); + used = recv_actor(desc, skb, 0, skb->len); + if (used <= 0) { + if (!copied) + copied = used; + break; + } + seq += used; + copied += used; + + if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { + consume_skb(skb); + ++seq; + break; + } + consume_skb(skb); + if (!desc->count) + break; + WRITE_ONCE(tp->copied_seq, seq); + } + WRITE_ONCE(tp->copied_seq, seq); + + tcp_rcv_space_adjust(sk); + + /* Clean up data we have read: This will do ACK frames. */ + if (copied > 0) + tcp_cleanup_rbuf(sk, copied); + + return copied; +} +EXPORT_SYMBOL(tcp_read_skb); + int tcp_peek_len(struct socket *sock) { return tcp_inq(sock->sk);