On 5/13/21 9:04 AM, Hangbin Liu wrote:
This patch adds two flags BPF_F_BROADCAST and BPF_F_EXCLUDE_INGRESS to
extend xdp_redirect_map for broadcast support.
Just few minor bits, other than that it's good to go, imho:
-static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifindex, u64 flags,
+static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifindex,
+ u64 flags, u64 flag_mask,
nit: const u64 flag_mask
void *lookup_elem(struct bpf_map *map, u32 key))
{
struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info);
/* Lower bits of the flags are used as return code on lookup failure */
- if (unlikely(flags > XDP_TX))
+ if (unlikely(flags & ~(BPF_F_ACTION_MASK | flag_mask)))
return XDP_ABORTED;
ri->tgt_value = lookup_elem(map, ifindex);
- if (unlikely(!ri->tgt_value)) {
+ if (unlikely(!ri->tgt_value) && !(flags & BPF_F_BROADCAST)) {
/* 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
@@ -1482,13 +1484,21 @@ static __always_inline int __bpf_xdp_redirect_map(struct bpf_map *map, u32 ifind
*/
ri->map_id = INT_MAX; /* Valid map id idr range: [1,INT_MAX[ */
ri->map_type = BPF_MAP_TYPE_UNSPEC;
- return flags;
+ return flags & BPF_F_ACTION_MASK;
}
ri->tgt_index = ifindex;
ri->map_id = map->id;
ri->map_type = map->map_type;
+ if (flags & BPF_F_BROADCAST) {
+ WRITE_ONCE(ri->map, map);
+ ri->flags = flags;
+ } else {
+ WRITE_ONCE(ri->map, NULL);
+ ri->flags = 0;
+ }
+
return XDP_REDIRECT;
}
[...]
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ec6d85a81744..78d1ec401b3a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2534,8 +2534,12 @@ union bpf_attr {
* The lower two bits of *flags* are used as the return code if
* the map lookup fails. This is so that the return value can be
* one of the XDP program return codes up to **XDP_TX**, as chosen
- * by the caller. Any higher bits in the *flags* argument must be
- * unset.
+ * by the caller. The higher bits of *flags* can be set to
+ * BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
+ *
+ * With BPF_F_BROADCAST the packet will be broadcasted to all the
+ * interfaces in the map. with BPF_F_EXCLUDE_INGRESS the ingress
nit: in the map, with
+ * interface will be excluded when do broadcasting.
*
* See also **bpf_redirect**\ (), which only supports redirecting
* to an ifindex, but doesn't require a map to do so.
@@ -5080,6 +5084,14 @@ enum {
BPF_F_BPRM_SECUREEXEC = (1ULL << 0),
};
+/* Flags for bpf_redirect_map helper */
+enum {
+ BPF_F_BROADCAST = (1ULL << 3),
+ BPF_F_EXCLUDE_INGRESS = (1ULL << 4),
+};
+
+#define BPF_F_ACTION_MASK (XDP_ABORTED | XDP_DROP | XDP_PASS | XDP_TX)
Why do we need to expose BPF_F_ACTION_MASK into the uapi header here?
My understanding is that this is only needed kernel-internal (and therefore
the mask itself has no meaning for a user)?
#define __bpf_md_ptr(type, name) \
union { \
type name; \
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 5dd3e866599a..a1a0c4e791c6 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -601,7 +601,8 @@ static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
static int cpu_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags, __cpu_map_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
+ __cpu_map_lookup_elem);
}
static int cpu_map_btf_id;
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 3980fb3bfb09..5262a62355a1 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -198,6 +198,7 @@ static void dev_map_free(struct bpf_map *map)
list_del_rcu(&dtab->list);
spin_unlock(&dev_map_lock);
+ bpf_clear_redirect_map(map);
synchronize_rcu();
/* Make sure prior __dev_map_entry_free() have completed. */
@@ -515,6 +516,99 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp,
return __xdp_enqueue(dev, xdp, dev_rx, dst->xdp_prog);
}
+static bool is_valid_dst(struct bpf_dtab_netdev *obj, struct xdp_buff *xdp,
+ int exclude_ifindex)
+{
+ if (!obj || obj->dev->ifindex == exclude_ifindex ||
+ !obj->dev->netdev_ops->ndo_xdp_xmit)
+ return false;
+
+ if (xdp_ok_fwd_dev(obj->dev, xdp->data_end - xdp->data))
+ return false;
+
+ return true;
+}
+
+static int dev_map_enqueue_clone(struct bpf_dtab_netdev *obj,
+ struct net_device *dev_rx,
+ struct xdp_frame *xdpf)
+{
+ struct xdp_frame *nxdpf;
+
+ nxdpf = xdpf_clone(xdpf);
+ if (!nxdpf)
+ return -ENOMEM;
+
+ bq_enqueue(obj->dev, nxdpf, dev_rx, obj->xdp_prog);
+
+ return 0;
+}
+
[...]
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 858276e72c68..b33f4c4b6d65 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -584,3 +584,32 @@ struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
return __xdp_build_skb_from_frame(xdpf, skb, dev);
}
EXPORT_SYMBOL_GPL(xdp_build_skb_from_frame);
+
+struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf)
+{
+ unsigned int headroom, totalsize;
+ struct xdp_frame *nxdpf;
+ struct page *page;
+ void *addr;
+
+ headroom = xdpf->headroom + sizeof(*xdpf);
+ totalsize = headroom + xdpf->len;
+
+ if (unlikely(totalsize > PAGE_SIZE))
+ return NULL;
+ page = dev_alloc_page();
+ if (!page)
+ return NULL;
+ addr = page_to_virt(page);
+
+ memcpy(addr, xdpf, totalsize);
+
+ nxdpf = addr;
+ nxdpf->data = addr + headroom;
+ nxdpf->frame_sz = PAGE_SIZE;
+ nxdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
+ nxdpf->mem.id = 0;
+
+ return nxdpf;
+}
+EXPORT_SYMBOL_GPL(xdpf_clone);
This doesn't have a module user, why it needs to be exported?
diff --git a/net/xdp/xskmap.c b/net/xdp/xskmap.c
index 67b4ce504852..9df75ea4a567 100644
--- a/net/xdp/xskmap.c
+++ b/net/xdp/xskmap.c
@@ -226,7 +226,8 @@ static int xsk_map_delete_elem(struct bpf_map *map, void *key)
static int xsk_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
{
- return __bpf_xdp_redirect_map(map, ifindex, flags, __xsk_map_lookup_elem);
+ return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
+ __xsk_map_lookup_elem);
}
void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
Thanks,
Daniel
