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authorBjörn Töpel <bjorn.topel@intel.com>2021-03-08 12:29:07 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2021-03-10 01:06:34 +0100
commitee75aef23afe6e88497151c127c13ed69f41aaa2 (patch)
tree2e6ca2aa0d6d1ac694002dd4aff11915473d4118 /include
parente6a4750ffe9d701c4d55212b14b615e63571d235 (diff)
downloadlinux-ee75aef23afe6e88497151c127c13ed69f41aaa2.tar.bz2
bpf, xdp: Restructure redirect actions
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. Here, the map type and id are added to bpf_redirect_info, instead of the actual map. Map type, map item/ifindex, and the map_id (if any) is passed to xdp_do_redirect(). For ifindex-based redirect, used by the bpf_redirect() XDP BFP helper, a special map type/id are used. Map type of UNSPEC together with map id equal to INT_MAX has the special meaning of an ifindex based redirect. Note that valid map ids are 1 inclusive, INT_MAX exclusive ([1,INT_MAX[). In addition to making the code easier to follow, using explicit type and id in bpf_redirect_info has a slight positive performance impact by avoiding a pointer indirection for the map type lookup, and instead use the cacheline for bpf_redirect_info. Since the actual map is not passed via bpf_redirect_info anymore, the map lookup is only done in the BPF helper. This means that the bpf_clear_redirect_map() function can be removed. The actual map item is RCU protected. 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. Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210308112907.559576-3-bjorn.topel@gmail.com
Diffstat (limited to 'include')
-rw-r--r--include/linux/filter.h10
-rw-r--r--include/trace/events/xdp.h62
2 files changed, 41 insertions, 31 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 008691fd3b58..b2b85b2cad8e 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -646,7 +646,8 @@ struct bpf_redirect_info {
u32 flags;
u32 tgt_index;
void *tgt_value;
- struct bpf_map *map;
+ u32 map_id;
+ enum bpf_map_type map_type;
u32 kern_flags;
struct bpf_nh_params nh;
};
@@ -1488,13 +1489,14 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind
* performs multiple lookups, the last one always takes
* precedence.
*/
- WRITE_ONCE(ri->map, NULL);
+ ri->map_id = INT_MAX; /* Valid map id idr range: [1,INT_MAX[ */
+ ri->map_type = BPF_MAP_TYPE_UNSPEC;
return flags;
}
- ri->flags = flags;
ri->tgt_index = ifindex;
- WRITE_ONCE(ri->map, map);
+ ri->map_id = map->id;
+ ri->map_type = map->map_type;
return XDP_REDIRECT;
}
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index 76a97176ab81..fcad3645a70b 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h
@@ -86,19 +86,15 @@ struct _bpf_dtab_netdev {
};
#endif /* __DEVMAP_OBJ_TYPE */
-#define devmap_ifindex(tgt, map) \
- (((map->map_type == BPF_MAP_TYPE_DEVMAP || \
- map->map_type == BPF_MAP_TYPE_DEVMAP_HASH)) ? \
- ((struct _bpf_dtab_netdev *)tgt)->dev->ifindex : 0)
-
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 bpf_map_type map_type,
+ u32 map_id, u32 index),
- TP_ARGS(dev, xdp, tgt, err, map, index),
+ TP_ARGS(dev, xdp, tgt, err, map_type, map_id, index),
TP_STRUCT__entry(
__field(int, prog_id)
@@ -111,14 +107,22 @@ DECLARE_EVENT_CLASS(xdp_redirect_template,
),
TP_fast_assign(
+ u32 ifindex = 0, map_index = index;
+
+ if (map_type == BPF_MAP_TYPE_DEVMAP || map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ ifindex = ((struct _bpf_dtab_netdev *)tgt)->dev->ifindex;
+ } else if (map_type == BPF_MAP_TYPE_UNSPEC && map_id == INT_MAX) {
+ ifindex = index;
+ map_index = 0;
+ }
+
__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;
- __entry->map_id = map ? map->id : 0;
- __entry->map_index = map ? index : 0;
+ __entry->to_ifindex = ifindex;
+ __entry->map_id = map_id;
+ __entry->map_index = map_index;
),
TP_printk("prog_id=%d action=%s ifindex=%d to_ifindex=%d err=%d"
@@ -133,45 +137,49 @@ 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 bpf_map_type map_type,
+ u32 map_id, u32 index),
+ TP_ARGS(dev, xdp, tgt, err, map_type, map_id, index)
);
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 bpf_map_type map_type,
+ u32 map_id, u32 index),
+ TP_ARGS(dev, xdp, tgt, err, map_type, map_id, index)
);
-#define _trace_xdp_redirect(dev, xdp, to) \
- trace_xdp_redirect(dev, xdp, NULL, 0, NULL, to)
+#define _trace_xdp_redirect(dev, xdp, to) \
+ trace_xdp_redirect(dev, xdp, NULL, 0, BPF_MAP_TYPE_UNSPEC, INT_MAX, to)
-#define _trace_xdp_redirect_err(dev, xdp, to, err) \
- trace_xdp_redirect_err(dev, xdp, NULL, err, NULL, to)
+#define _trace_xdp_redirect_err(dev, xdp, to, err) \
+ trace_xdp_redirect_err(dev, xdp, NULL, err, BPF_MAP_TYPE_UNSPEC, INT_MAX, to)
-#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, map_type, map_id, index) \
+ trace_xdp_redirect(dev, xdp, to, 0, map_type, map_id, index)
-#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, map_type, map_id, index, err) \
+ trace_xdp_redirect_err(dev, xdp, to, err, map_type, map_id, index)
/* 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 bpf_map_type map_type,
+ u32 map_id, u32 index),
+ TP_ARGS(dev, xdp, tgt, err, map_type, map_id, index)
);
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 bpf_map_type map_type,
+ u32 map_id, u32 index),
+ TP_ARGS(dev, xdp, tgt, err, map_type, map_id, index)
);
TRACE_EVENT(xdp_cpumap_kthread,