From: Björn Töpel <bjorn.topel@xxxxxxxxx>
The XDP_REDIRECT implementations for maps and non-maps are fairly
similar, but obviously need to take different code paths depending on
if the target is using a map or not. Today, the redirect targets for
XDP either uses a map, or is based on ifindex.
Future commits will introduce yet another redirect target via the a
new helper, bpf_redirect_xsk(). To pave the way for that, we introduce
an explicit redirect type to bpf_redirect_info. This makes the code
easier to follow, and makes it easier to add new redirect targets.
Further, using an explicit type in bpf_redirect_info has a slight
positive performance impact by avoiding a pointer indirection for the
map type lookup, and instead use the hot cacheline for
bpf_redirect_info.
The bpf_redirect_info flags member is not used by XDP, and not
read/written any more. The map member is only written to when
required/used, and not unconditionally.
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
---
include/linux/filter.h | 9 ++
include/trace/events/xdp.h | 46 +++++++----
net/core/filter.c | 164 ++++++++++++++++++-------------------
3 files changed, 117 insertions(+), 102 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 7fdce5407214..5fc336a271c2 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -637,10 +637,19 @@ struct bpf_redirect_info {
u32 tgt_index;
void *tgt_value;
struct bpf_map *map;
+ u32 tgt_type;
u32 kern_flags;
struct bpf_nh_params nh;
};
+enum xdp_redirect_type {
+ XDP_REDIR_UNSET,
+ XDP_REDIR_DEV_IFINDEX,
+ XDP_REDIR_DEV_MAP,
+ XDP_REDIR_CPU_MAP,
+ XDP_REDIR_XSK_MAP,
+};
+
DECLARE_PER_CPU(struct bpf_redirect_info, bpf_redirect_info);
/* flags for bpf_redirect_info kern_flags */
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 76a97176ab81..0e17b9a74f28 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -96,9 +96,10 @@ DECLARE_EVENT_CLASS(xdp_redirect_template,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
- TP_ARGS(dev, xdp, tgt, err, map, index),
+ TP_ARGS(dev, xdp, tgt, err, type, ri),
TP_STRUCT__entry(
__field(int, prog_id)
@@ -111,12 +112,19 @@ DECLARE_EVENT_CLASS(xdp_redirect_template,
),
TP_fast_assign(
+ struct bpf_map *map = NULL;
+ u32 index = ri->tgt_index;
+
+ if (type == XDP_REDIR_DEV_MAP || type == XDP_REDIR_CPU_MAP ||
+ type == XDP_REDIR_XSK_MAP)
+ map = READ_ONCE(ri->map);
+
__entry->prog_id = xdp->aux->id;
__entry->act = XDP_REDIRECT;
__entry->ifindex = dev->ifindex;
__entry->err = err;
__entry->to_ifindex = map ? devmap_ifindex(tgt, map) :
- index;
+ (u32)(long)tgt;
__entry->map_id = map ? map->id : 0;
__entry->map_index = map ? index : 0;
),
@@ -133,45 +141,49 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
#define _trace_xdp_redirect(dev, xdp, to) \
- trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to)
+ trace_xdp_redirect(dev, xdp, NULL, 0, XDP_REDIR_DEV_IFINDEX, NULL)
#define _trace_xdp_redirect_err(dev, xdp, to, err) \
- trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to)
+ trace_xdp_redirect_err(dev, xdp, NULL, err, XDP_REDIR_DEV_IFINDEX, NULL)
-#define _trace_xdp_redirect_map(dev, xdp, to, map, index) \
- trace_xdp_redirect(dev, xdp, to, 0, map, index)
+#define _trace_xdp_redirect_map(dev, xdp, to, type, ri) \
+ trace_xdp_redirect(dev, xdp, to, 0, type, ri)
-#define _trace_xdp_redirect_map_err(dev, xdp, to, map, index, err) \
- trace_xdp_redirect_err(dev, xdp, to, err, map, index)
+#define _trace_xdp_redirect_map_err(dev, xdp, to, type, ri, err) \
+ trace_xdp_redirect_err(dev, xdp, to, err, type, ri)
/* not used anymore, but kept around so as not to break old programs */
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
DEFINE_EVENT(xdp_redirect_template, xdp_redirect_map_err,
TP_PROTO(const struct net_device *dev,
const struct bpf_prog *xdp,
const void *tgt, int err,
- const struct bpf_map *map, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index)
+ enum xdp_redirect_type type,
+ const struct bpf_redirect_info *ri),
+ TP_ARGS(dev, xdp, tgt, err, type, ri)
);
TRACE_EVENT(xdp_cpumap_kthread,
diff --git a/net/core/filter.c b/net/core/filter.c
index 9ab94e90d660..5f31e21be531 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3923,23 +3923,6 @@ static const struct bpf_func_proto bpf_xdp_adjust_meta_proto = {
.arg2_type = ARG_ANYTHING,
};
-static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
- struct bpf_map *map, struct xdp_buff *xdp)
-{
- switch (map->map_type) {
- case BPF_MAP_TYPE_DEVMAP:
- case BPF_MAP_TYPE_DEVMAP_HASH:
- return dev_map_enqueue(fwd, xdp, dev_rx);
- case BPF_MAP_TYPE_CPUMAP:
- return cpu_map_enqueue(fwd, xdp, dev_rx);
- case BPF_MAP_TYPE_XSKMAP:
- return __xsk_map_redirect(fwd, xdp);
- default:
- return -EBADRQC;
- }
- return 0;
-}
-
void xdp_do_flush(void)
{
__dev_flush();
@@ -3948,22 +3931,6 @@ void xdp_do_flush(void)
}
EXPORT_SYMBOL_GPL(xdp_do_flush);
-static inline void *__xdp_map_lookup_elem(struct bpf_map *map, u32 index)
-{
- switch (map->map_type) {
- case BPF_MAP_TYPE_DEVMAP:
- return __dev_map_lookup_elem(map, index);
- case BPF_MAP_TYPE_DEVMAP_HASH:
- return __dev_map_hash_lookup_elem(map, index);
- case BPF_MAP_TYPE_CPUMAP:
- return __cpu_map_lookup_elem(map, index);
- case BPF_MAP_TYPE_XSKMAP:
- return __xsk_map_lookup_elem(map, index);
- default:
- return NULL;
- }
-}
-
void bpf_clear_redirect_map(struct bpf_map *map)
{
struct bpf_redirect_info *ri;
@@ -3985,34 +3952,42 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- struct bpf_map *map = READ_ONCE(ri->map);
- u32 index = ri->tgt_index;
+ enum xdp_redirect_type type = ri->tgt_type;
void *fwd = ri->tgt_value;
int err;
- ri->tgt_index = 0;
+ ri->tgt_type = XDP_REDIR_UNSET;
ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
- if (unlikely(!map)) {
- fwd = dev_get_by_index_rcu(dev_net(dev), index);
+ switch (type) {
+ case XDP_REDIR_DEV_IFINDEX:
+ fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd);
if (unlikely(!fwd)) {
err = -EINVAL;
- goto err;
+ break;
}
-
err = dev_xdp_enqueue(fwd, xdp, dev);
- } else {
- err = __bpf_tx_xdp_map(dev, fwd, map, xdp);
+ break;
+ case XDP_REDIR_DEV_MAP:
+ err = dev_map_enqueue(fwd, xdp, dev);
+ break;
+ case XDP_REDIR_CPU_MAP:
+ err = cpu_map_enqueue(fwd, xdp, dev);
+ break;
+ case XDP_REDIR_XSK_MAP:
+ err = __xsk_map_redirect(fwd, xdp);
+ break;
+ default:
+ err = -EBADRQC;
}
if (unlikely(err))
goto err;
- _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index);
+ _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri);
return 0;
err:
- _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err);
+ _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err);
return err;
}
EXPORT_SYMBOL_GPL(xdp_do_redirect);
@@ -4021,41 +3996,40 @@ static int xdp_do_generic_redirect_map(struct net_device *dev,
struct sk_buff *skb,
struct xdp_buff *xdp,
struct bpf_prog *xdp_prog,
- struct bpf_map *map)
+ void *fwd,
+ enum xdp_redirect_type type)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- u32 index = ri->tgt_index;
- void *fwd = ri->tgt_value;
- int err = 0;
-
- ri->tgt_index = 0;
- ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
+ int err;
- if (map->map_type == BPF_MAP_TYPE_DEVMAP ||
- map->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ switch (type) {
+ case XDP_REDIR_DEV_MAP: {
struct bpf_dtab_netdev *dst = fwd;
err = dev_map_generic_redirect(dst, skb, xdp_prog);
if (unlikely(err))
goto err;
- } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+ break;
+ }
+ case XDP_REDIR_XSK_MAP: {
struct xdp_sock *xs = fwd;
err = xsk_generic_rcv(xs, xdp);
if (err)
goto err;
consume_skb(skb);
- } else {
+ break;
+ }
+ default:
/* TODO: Handle BPF_MAP_TYPE_CPUMAP */
err = -EBADRQC;
goto err;
}
- _trace_xdp_redirect_map(dev, xdp_prog, fwd, map, index);
+ _trace_xdp_redirect_map(dev, xdp_prog, fwd, type, ri);
return 0;
err:
- _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err);
+ _trace_xdp_redirect_map_err(dev, xdp_prog, fwd, type, ri, err);
return err;
}
@@ -4063,29 +4037,31 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
struct xdp_buff *xdp, struct bpf_prog *xdp_prog)
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
- struct bpf_map *map = READ_ONCE(ri->map);
- u32 index = ri->tgt_index;
- struct net_device *fwd;
+ enum xdp_redirect_type type = ri->tgt_type;
+ void *fwd = ri->tgt_value;
int err = 0;
- if (map)
- return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog,
- map);
- ri->tgt_index = 0;
- fwd = dev_get_by_index_rcu(dev_net(dev), index);
- if (unlikely(!fwd)) {
- err = -EINVAL;
- goto err;
- }
+ ri->tgt_type = XDP_REDIR_UNSET;
+ ri->tgt_value = NULL;
- err = xdp_ok_fwd_dev(fwd, skb->len);
- if (unlikely(err))
- goto err;
+ if (type == XDP_REDIR_DEV_IFINDEX) {
+ fwd = dev_get_by_index_rcu(dev_net(dev), (u32)(long)fwd);
+ if (unlikely(!fwd)) {
+ err = -EINVAL;
+ goto err;
+ }
- skb->dev = fwd;
- _trace_xdp_redirect(dev, xdp_prog, index);
- generic_xdp_tx(skb, xdp_prog);
- return 0;
+ err = xdp_ok_fwd_dev(fwd, skb->len);
+ if (unlikely(err))
+ goto err;
+
+ skb->dev = fwd;
+ _trace_xdp_redirect(dev, xdp_prog, index);
+ generic_xdp_tx(skb, xdp_prog);
+ return 0;
+ }
+
+ return xdp_do_generic_redirect_map(dev, skb, xdp, xdp_prog, fwd, type);
err:
_trace_xdp_redirect_err(dev, xdp_prog, index, err);
return err;
@@ -4098,10 +4074,9 @@ BPF_CALL_2(bpf_xdp_redirect, u32, ifindex, u64, flags)
if (unlikely(flags))
return XDP_ABORTED;
- ri->flags = flags;
- ri->tgt_index = ifindex;
- ri->tgt_value = NULL;
- WRITE_ONCE(ri->map, NULL);
+ ri->tgt_type = XDP_REDIR_DEV_IFINDEX;
+ ri->tgt_index = 0;
+ ri->tgt_value = (void *)(long)ifindex;
return XDP_REDIRECT;
}
@@ -4123,18 +4098,37 @@ BPF_CALL_3(bpf_xdp_redirect_map, struct bpf_map *, map, u32, ifindex,
if (unlikely(flags > XDP_TX))
return XDP_ABORTED;
- ri->tgt_value = __xdp_map_lookup_elem(map, ifindex);
+ switch (map->map_type) {
+ case BPF_MAP_TYPE_DEVMAP:
+ ri->tgt_value = __dev_map_lookup_elem(map, ifindex);
+ ri->tgt_type = XDP_REDIR_DEV_MAP;
+ break;
+ case BPF_MAP_TYPE_DEVMAP_HASH:
+ ri->tgt_value = __dev_map_hash_lookup_elem(map, ifindex);
+ ri->tgt_type = XDP_REDIR_DEV_MAP;
+ break;
+ case BPF_MAP_TYPE_CPUMAP:
+ ri->tgt_value = __cpu_map_lookup_elem(map, ifindex);
+ ri->tgt_type = XDP_REDIR_CPU_MAP;
+ break;
+ case BPF_MAP_TYPE_XSKMAP:
+ ri->tgt_value = __xsk_map_lookup_elem(map, ifindex);
+ ri->tgt_type = XDP_REDIR_XSK_MAP;
+ break;
+ default:
+ ri->tgt_value = NULL;
+ }
+
if (unlikely(!ri->tgt_value)) {
/* If the lookup fails we want to clear out the state in the
* redirect_info struct completely, so that if an eBPF program
* performs multiple lookups, the last one always takes
* precedence.
*/
- WRITE_ONCE(ri->map, NULL);
+ ri->tgt_type = XDP_REDIR_UNSET;
return flags;
}
- ri->flags = flags;
ri->tgt_index = ifindex;
WRITE_ONCE(ri->map, map);
--
2.27.0
