[PATCH net-next V2 01/11] net: sock: introduce SOCK_XDP

Jason Wang
2018-09-12T03:16:59Z

This patch introduces a new sock flag - SOCK_XDP. This will be used
for notifying the upper layer that XDP program is attached on the
lower socket, and requires for extra headroom.

TUN will be the first user.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/tun.c | 19 +++++++++++++++++++
include/net/sock.h | 1 +
2 files changed, 20 insertions(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index ebd07ad82431..2c548bd20393 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -869,6 +869,9 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
tun_napi_init(tun, tfile, napi);
}

+ if (rtnl_dereference(tun->xdp_prog))
+ sock_set_flag(&tfile->sk, SOCK_XDP);
+
tun_set_real_num_queues(tun);

/* device is allowed to go away first, so no need to hold extra
@@ -1241,13 +1244,29 @@ static int tun_xdp_set(struct net_device *dev, struct bpf_prog *prog,
struct netlink_ext_ack *extack)
{
struct tun_struct *tun = netdev_priv(dev);
+ struct tun_file *tfile;
struct bpf_prog *old_prog;
+ int i;

old_prog = rtnl_dereference(tun->xdp_prog);
rcu_assign_pointer(tun->xdp_prog, prog);
if (old_prog)
bpf_prog_put(old_prog);

+ for (i = 0; i < tun->numqueues; i++) {
+ tfile = rtnl_dereference(tun->tfiles[i]);
+ if (prog)
+ sock_set_flag(&tfile->sk, SOCK_XDP);
+ else
+ sock_reset_flag(&tfile->sk, SOCK_XDP);
+ }
+ list_for_each_entry(tfile, &tun->disabled, next) {
+ if (prog)
+ sock_set_flag(&tfile->sk, SOCK_XDP);
+ else
+ sock_reset_flag(&tfile->sk, SOCK_XDP);
+ }
+
return 0;
}

diff --git a/include/net/sock.h b/include/net/sock.h
index 433f45fc2d68..38cae35f6e16 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -800,6 +800,7 @@ enum sock_flags {
SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
SOCK_RCU_FREE, /* wait rcu grace period in sk_destruct() */
SOCK_TXTIME,
+ SOCK_XDP, /* XDP is attached */
};

#define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
--
2.17.1