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bpf, netkit: Add indirect call wrapper for fetching peer dev 

ndo_get_peer_dev is used in tcx BPF fast path, therefore make use of
indirect call wrapper and therefore optimize the bpf_redirect_peer()
internal handling a bit. Add a small skb_get_peer_dev() wrapper which
utilizes the INDIRECT_CALL_1() macro instead of open coding.

Future work could potentially add a peer pointer directly into struct
net_device in future and convert veth and netkit over to use it so
that eventually ndo_get_peer_dev can be removed.

Co-developed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20231114004220.6495-7-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
Daniel Borkmann 2023-11-14 01:42:18 +01:00 committed by Martin KaFai Lau
parent 024ee930cb
commit 2c22542570
3 changed files with 21 additions and 6 deletions
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3
drivers/net/netkit.c
View File

@ -7,6 +7,7 @@
#include <linux/filter.h> #include <linux/filter.h>
#include <linux/netfilter_netdev.h> #include <linux/netfilter_netdev.h>
#include <linux/bpf_mprog.h> #include <linux/bpf_mprog.h>
#include <linux/indirect_call_wrapper.h>
#include <net/netkit.h> #include <net/netkit.h>
#include <net/dst.h> #include <net/dst.h>
@ -177,7 +178,7 @@ static void netkit_set_headroom(struct net_device *dev, int headroom)
rcu_read_unlock(); rcu_read_unlock();
} }
static struct net_device *netkit_peer_dev(struct net_device *dev) INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev)
{ {
return rcu_dereference(netkit_priv(dev)->peer); return rcu_dereference(netkit_priv(dev)->peer);
} }

6
include/net/netkit.h
View File

@ -10,6 +10,7 @@ int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog);
int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog); int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);
int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog); int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog);
int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr); int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr);
INDIRECT_CALLABLE_DECLARE(struct net_device *netkit_peer_dev(struct net_device *dev));
#else #else
static inline int netkit_prog_attach(const union bpf_attr *attr, static inline int netkit_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog) struct bpf_prog *prog)
@ -34,5 +35,10 @@ static inline int netkit_prog_query(const union bpf_attr *attr,
{ {
return -EINVAL; return -EINVAL;
} }
static inline struct net_device *netkit_peer_dev(struct net_device *dev)
{
return NULL;
}
#endif /* CONFIG_NETKIT */ #endif /* CONFIG_NETKIT */
#endif /* __NET_NETKIT_H */ #endif /* __NET_NETKIT_H */

18
net/core/filter.c
View File

@ -81,6 +81,7 @@
#include <net/xdp.h> #include <net/xdp.h>
#include <net/mptcp.h> #include <net/mptcp.h>
#include <net/netfilter/nf_conntrack_bpf.h> #include <net/netfilter/nf_conntrack_bpf.h>
#include <net/netkit.h>
#include <linux/un.h> #include <linux/un.h>
#include "dev.h" #include "dev.h"
@ -2468,6 +2469,16 @@ static const struct bpf_func_proto bpf_clone_redirect_proto = {
DEFINE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info); DEFINE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info);
EXPORT_PER_CPU_SYMBOL_GPL(bpf_redirect_info); EXPORT_PER_CPU_SYMBOL_GPL(bpf_redirect_info);
static struct net_device *skb_get_peer_dev(struct net_device *dev)
{
const struct net_device_ops *ops = dev->netdev_ops;
if (likely(ops->ndo_get_peer_dev))
return INDIRECT_CALL_1(ops->ndo_get_peer_dev,
netkit_peer_dev, dev);
return NULL;
}
int skb_do_redirect(struct sk_buff *skb) int skb_do_redirect(struct sk_buff *skb)
{ {
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
@ -2481,12 +2492,9 @@ int skb_do_redirect(struct sk_buff *skb)
if (unlikely(!dev)) if (unlikely(!dev))
goto out_drop; goto out_drop;
if (flags & BPF_F_PEER) { if (flags & BPF_F_PEER) {
const struct net_device_ops *ops = dev->netdev_ops; if (unlikely(!skb_at_tc_ingress(skb)))
if (unlikely(!ops->ndo_get_peer_dev ||
!skb_at_tc_ingress(skb)))
goto out_drop; goto out_drop;
dev = ops->ndo_get_peer_dev(dev); dev = skb_get_peer_dev(dev);
if (unlikely(!dev || if (unlikely(!dev ||
!(dev->flags & IFF_UP) || !(dev->flags & IFF_UP) ||
net_eq(net, dev_net(dev)))) net_eq(net, dev_net(dev))))