[RFC net-next 07/18] tun: set offloaded xdp program

[Prashant Bhole]

From: Jason Wang <address@hidden>

This patch introduces an ioctl way to set an offloaded XDP program
to tun driver. This ioctl will be used by qemu to offload XDP program
from virtio_net in the guest.

Signed-off-by: Jason Wang <address@hidden>
Signed-off-by: Prashant Bhole <address@hidden>
---
 drivers/net/tun.c           | 19 ++++++++++++++-----
 include/uapi/linux/if_tun.h |  1 +
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index d078b4659897..ecb49101b0b5 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -241,6 +241,7 @@ struct tun_struct {
        struct bpf_prog __rcu *xdp_prog;
        struct tun_prog __rcu *steering_prog;
        struct tun_prog __rcu *filter_prog;
+       struct tun_prog __rcu *offloaded_xdp_prog;
        struct ethtool_link_ksettings link_ksettings;
 };
 
@@ -2256,7 +2257,7 @@ static void tun_prog_free(struct rcu_head *rcu)
 {
        struct tun_prog *prog = container_of(rcu, struct tun_prog, rcu);
 
-       bpf_prog_destroy(prog->prog);
+       bpf_prog_put(prog->prog);
        kfree(prog);
 }
 
@@ -2301,6 +2302,7 @@ static void tun_free_netdev(struct net_device *dev)
        security_tun_dev_free_security(tun->security);
        __tun_set_ebpf(tun, &tun->steering_prog, NULL);
        __tun_set_ebpf(tun, &tun->filter_prog, NULL);
+       __tun_set_ebpf(tun, &tun->offloaded_xdp_prog, NULL);
 }
 
 static void tun_setup(struct net_device *dev)
@@ -3036,7 +3038,7 @@ static int tun_set_queue(struct file *file, struct ifreq 
*ifr)
 }
 
 static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog **prog_p,
-                       void __user *data)
+                       void __user *data, int type)
 {
        struct bpf_prog *prog;
        int fd;
@@ -3047,7 +3049,7 @@ static int tun_set_ebpf(struct tun_struct *tun, struct 
tun_prog **prog_p,
        if (fd == -1) {
                prog = NULL;
        } else {
-               prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER);
+               prog = bpf_prog_get_type(fd, type);
                if (IS_ERR(prog))
                        return PTR_ERR(prog);
        }
@@ -3345,11 +3347,18 @@ static long __tun_chr_ioctl(struct file *file, unsigned 
int cmd,
                break;
 
        case TUNSETSTEERINGEBPF:
-               ret = tun_set_ebpf(tun, &tun->steering_prog, argp);
+               ret = tun_set_ebpf(tun, &tun->steering_prog, argp,
+                                  BPF_PROG_TYPE_SOCKET_FILTER);
                break;
 
        case TUNSETFILTEREBPF:
-               ret = tun_set_ebpf(tun, &tun->filter_prog, argp);
+               ret = tun_set_ebpf(tun, &tun->filter_prog, argp,
+                                  BPF_PROG_TYPE_SOCKET_FILTER);
+               break;
+
+       case TUNSETOFFLOADEDXDP:
+               ret = tun_set_ebpf(tun, &tun->offloaded_xdp_prog, argp,
+                                  BPF_PROG_TYPE_XDP);
                break;
 
        case TUNSETCARRIER:
diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 454ae31b93c7..21dbd8db2401 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -61,6 +61,7 @@
 #define TUNSETFILTEREBPF _IOR('T', 225, int)
 #define TUNSETCARRIER _IOW('T', 226, int)
 #define TUNGETDEVNETNS _IO('T', 227)
+#define TUNSETOFFLOADEDXDP _IOW('T', 228, int)
 
 /* TUNSETIFF ifr flags */
 #define IFF_TUN                0x0001
-- 
2.20.1