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authorWillem de Bruijn <willemb@google.com>2017-08-03 23:29:40 +0300
committerDavid S. Miller <davem@davemloft.net>2017-08-04 07:37:29 +0300
commit76851d1212c11365362525e1e2c0a18c97478e6b (patch)
treea9f9c1795f51c31d46e8282674e5d45f46ce1cbe /net/core/sock.c
parent52267790ef52d7513879238ca9fac22c1733e0e3 (diff)
downloadlinux-76851d1212c11365362525e1e2c0a18c97478e6b.tar.xz
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 <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c18
1 files changed, 18 insertions, 0 deletions
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).