From 76851d1212c11365362525e1e2c0a18c97478e6b Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Thu, 3 Aug 2017 16:29:40 -0400 Subject: sock: add SOCK_ZEROCOPY sockopt The send call ignores unknown flags. Legacy applications may already unwittingly pass MSG_ZEROCOPY. Continue to ignore this flag unless a socket opts in to zerocopy. Introduce socket option SO_ZEROCOPY to enable MSG_ZEROCOPY processing. Processes can also query this socket option to detect kernel support for the feature. Older kernels will return ENOPROTOOPT. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/core/sock.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index e8b696858cad..9ea988d25b0a 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1055,6 +1055,20 @@ set_rcvbuf: if (val == 1) dst_negative_advice(sk); break; + + case SO_ZEROCOPY: + if (sk->sk_family != PF_INET && sk->sk_family != PF_INET6) + ret = -ENOTSUPP; + else if (sk->sk_protocol != IPPROTO_TCP) + ret = -ENOTSUPP; + else if (sk->sk_state != TCP_CLOSE) + ret = -EBUSY; + else if (val < 0 || val > 1) + ret = -EINVAL; + else + sock_valbool_flag(sk, SOCK_ZEROCOPY, valbool); + break; + default: ret = -ENOPROTOOPT; break; @@ -1383,6 +1397,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname, v.val64 = sock_gen_cookie(sk); break; + case SO_ZEROCOPY: + v.val = sock_flag(sk, SOCK_ZEROCOPY); + break; + default: /* We implement the SO_SNDLOWAT etc to not be settable * (1003.1g 7). -- cgit v1.2.3