From ef64a54f6e558155b4f149bb10666b9e914b6c54 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Tue, 21 Feb 2012 07:31:34 +0000 Subject: sock: Introduce the SO_PEEK_OFF sock option This one specifies where to start MSG_PEEK-ing queue data from. When set to negative value means that MSG_PEEK works as ususally -- peeks from the head of the queue always. When some bytes are peeked from queue and the peeking offset is non negative it is moved forward so that the next peek will return next portion of data. When non-peeking recvmsg occurs and the peeking offset is non negative is is moved backward so that the next peek will still peek the proper data (i.e. the one that would have been picked if there were no non peeking recv in between). The offset is set using per-proto opteration to let the protocol handle the locking issues and to check whether the peeking offset feature is supported by the protocol the socket belongs to. Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- include/net/sock.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'include/net') diff --git a/include/net/sock.h b/include/net/sock.h index 91c1c8baf020..9c0553b9e451 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -357,6 +357,7 @@ struct sock { struct page *sk_sndmsg_page; struct sk_buff *sk_send_head; __u32 sk_sndmsg_off; + __s32 sk_peek_off; int sk_write_pending; #ifdef CONFIG_SECURITY void *sk_security; @@ -373,6 +374,30 @@ struct sock { void (*sk_destruct)(struct sock *sk); }; +static inline int sk_peek_offset(struct sock *sk, int flags) +{ + if ((flags & MSG_PEEK) && (sk->sk_peek_off >= 0)) + return sk->sk_peek_off; + else + return 0; +} + +static inline void sk_peek_offset_bwd(struct sock *sk, int val) +{ + if (sk->sk_peek_off >= 0) { + if (sk->sk_peek_off >= val) + sk->sk_peek_off -= val; + else + sk->sk_peek_off = 0; + } +} + +static inline void sk_peek_offset_fwd(struct sock *sk, int val) +{ + if (sk->sk_peek_off >= 0) + sk->sk_peek_off += val; +} + /* * Hashed lists helper routines */ -- cgit v1.2.3