As UMH runs under RTNL, it cannot attach XDP from userspace. Thus the
kernel, xdp_flow module, installs the XDP program.
NOTE: As an RFC, XDP-related logic is emulating dev_change_xdp_fd().
I'm thinking I should factor out the logic from dev_change_xdp_fd() and
export it instead.
Signed-off-by: Toshiaki Makita <toshiaki.maki...@gmail.com>
---
include/linux/netdevice.h | 4 +++
net/core/dev.c | 11 ++++---
net/xdp_flow/xdp_flow_kern_mod.c | 63 ++++++++++++++++++++++++++++++++++++----
3 files changed, 69 insertions(+), 9 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8829295..c99e022 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3678,6 +3678,10 @@ struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb,
struct net_device *dev,
struct netdev_queue *txq, int *ret);
typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
+int dev_xdp_install(struct net_device *dev, bpf_op_t bpf_op,
+ struct netlink_ext_ack *extack, u32 flags,
+ struct bpf_prog *prog);
+int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp);
int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack,
int fd, u32 flags);
u32 __dev_xdp_query(struct net_device *dev, bpf_op_t xdp_op,
diff --git a/net/core/dev.c b/net/core/dev.c
index fc676b2..a45d2e4 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5145,7 +5145,7 @@ static void __netif_receive_skb_list(struct list_head
*head)
memalloc_noreclaim_restore(noreclaim_flag);
}
-static int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp)
+int generic_xdp_install(struct net_device *dev, struct netdev_bpf *xdp)
{
struct bpf_prog *old = rtnl_dereference(dev->xdp_prog);
struct bpf_prog *new = xdp->prog;
@@ -5177,6 +5177,7 @@ static int generic_xdp_install(struct net_device *dev,
struct netdev_bpf *xdp)
return ret;
}
+EXPORT_SYMBOL_GPL(generic_xdp_install);
static int netif_receive_skb_internal(struct sk_buff *skb)
{
@@ -8001,10 +8002,11 @@ u32 __dev_xdp_query(struct net_device *dev, bpf_op_t
bpf_op,
return xdp.prog_id;
}
+EXPORT_SYMBOL_GPL(__dev_xdp_query);
-static int dev_xdp_install(struct net_device *dev, bpf_op_t bpf_op,
- struct netlink_ext_ack *extack, u32 flags,
- struct bpf_prog *prog)
+int dev_xdp_install(struct net_device *dev, bpf_op_t bpf_op,
+ struct netlink_ext_ack *extack, u32 flags,
+ struct bpf_prog *prog)
{
struct netdev_bpf xdp;
@@ -8019,6 +8021,7 @@ static int dev_xdp_install(struct net_device *dev,
bpf_op_t bpf_op,
return bpf_op(dev, &xdp);
}
+EXPORT_SYMBOL_GPL(dev_xdp_install);
static void dev_xdp_uninstall(struct net_device *dev)
{
diff --git a/net/xdp_flow/xdp_flow_kern_mod.c b/net/xdp_flow/xdp_flow_kern_mod.c
index 823ab65..9cf527d 100644
--- a/net/xdp_flow/xdp_flow_kern_mod.c
+++ b/net/xdp_flow/xdp_flow_kern_mod.c
@@ -116,10 +116,26 @@ static int xdp_flow_setup_block_cb(enum tc_setup_type
type, void *type_data,
static int xdp_flow_setup_bind(struct net_device *dev,
struct netlink_ext_ack *extack)
{
+ enum bpf_prog_type attach_type = BPF_PROG_TYPE_XDP;
struct mbox_request *req;
+ bpf_op_t bpf_op, bpf_chk;
+ struct bpf_prog *prog;
u32 id = 0;
int err;
+ bpf_op = bpf_chk = dev->netdev_ops->ndo_bpf;
+ if (!bpf_op)
+ bpf_op = generic_xdp_install;
+ else
+ bpf_chk = generic_xdp_install;
+
+ /* TODO: These checks should be unified with net core */
+ if (__dev_xdp_query(dev, bpf_chk, XDP_QUERY_PROG))
+ return -EEXIST;
+
+ if (__dev_xdp_query(dev, bpf_op, XDP_QUERY_PROG))
+ return -EBUSY;
+
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
return -ENOMEM;
@@ -129,21 +145,56 @@ static int xdp_flow_setup_bind(struct net_device *dev,
/* Load bpf in UMH and get prog id */
err = transact_umh(req, &id);
+ if (err)
+ goto out;
+
+ prog = bpf_prog_get_by_id(id);
+ if (IS_ERR(prog)) {
+ err = PTR_ERR(prog);
+ goto err_umh;
+ }
+
+ if (!bpf_prog_get_ok(prog, &attach_type, false)) {
+ err = -EINVAL;
+ goto err_prog;
+ }
- /* TODO: id will be used to attach bpf prog to XDP
- * As we have rtnl_lock, UMH cannot attach prog to XDP
- */
+ /* As we have rtnl_lock, install XDP in kernel */
+ err = dev_xdp_install(dev, bpf_op, extack, 0, prog);
+ if (err)
+ goto err_prog;
+ /* TODO: Should get prog once more and save it for later check */
+out:
kfree(req);
return err;
+err_prog:
+ bpf_prog_put(prog);
+err_umh:
+ req->cmd = XDP_FLOW_CMD_UNLOAD;
+ transact_umh(req, NULL);
+
+ goto out;
}
static int xdp_flow_setup_unbind(struct net_device *dev,
struct netlink_ext_ack *extack)
{
struct mbox_request *req;
- int err;
+ int err, ret = 0;
+ bpf_op_t bpf_op;
+
+ bpf_op = dev->netdev_ops->ndo_bpf;
+ if (!bpf_op)
+ bpf_op = generic_xdp_install;
+
+ /* TODO: Should check if prog is not changed */
+ err = dev_xdp_install(dev, bpf_op, extack, 0, NULL);
+ if (err) {
+ pr_warn("Failed to uninstall XDP prog: %d\n", err);
+ ret = err;
+ }
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
@@ -153,10 +204,12 @@ static int xdp_flow_setup_unbind(struct net_device *dev,
req->ifindex = dev->ifindex;
err = transact_umh(req, NULL);
+ if (err)
+ ret = err;
kfree(req);
- return err;
+ return ret;
}
static int xdp_flow_setup(struct net_device *dev, bool do_bind,
--
1.8.3.1
