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authorToke Høiland-Jørgensen <toke@redhat.com>2020-10-20 23:25:56 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2020-10-22 01:28:54 +0200
commitba452c9e996d8a4c347b32805f91abb70de5de7e (patch)
tree7cc639674290dda9b607ed44dc572b30f55502a7 /tools
parentc5eb48e89286510d638844104a6f6582a4838a32 (diff)
bpf: Fix bpf_redirect_neigh helper api to support supplying nexthop
Based on the discussion in [0], update the bpf_redirect_neigh() helper to accept an optional parameter specifying the nexthop information. This makes it possible to combine bpf_fib_lookup() and bpf_redirect_neigh() without incurring a duplicate FIB lookup - since the FIB lookup helper will return the nexthop information even if no neighbour is present, this can simply be passed on to bpf_redirect_neigh() if bpf_fib_lookup() returns BPF_FIB_LKUP_RET_NO_NEIGH. Thus fix & extend it before helper API is frozen. [0] https://lore.kernel.org/bpf/393e17fc-d187-3a8d-2f0d-a627c7c63fca@iogearbox.net/ Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: David Ahern <dsahern@kernel.org> Link: https://lore.kernel.org/bpf/160322915615.32199.1187570224032024535.stgit@toke.dk
Diffstat (limited to 'tools')
-rw-r--r--tools/include/uapi/linux/bpf.h22
1 files changed, 18 insertions, 4 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index bf5a99d803e4..e6ceac3f7d62 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3677,15 +3677,19 @@ union bpf_attr {
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
- * long bpf_redirect_neigh(u32 ifindex, u64 flags)
+ * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
* Description
* Redirect the packet to another net device of index *ifindex*
* and fill in L2 addresses from neighboring subsystem. This helper
* is somewhat similar to **bpf_redirect**\ (), except that it
* populates L2 addresses as well, meaning, internally, the helper
- * performs a FIB lookup based on the skb's networking header to
- * get the address of the next hop and then relies on the neighbor
- * lookup for the L2 address of the nexthop.
+ * relies on the neighbor lookup for the L2 address of the nexthop.
+ *
+ * The helper will perform a FIB lookup based on the skb's
+ * networking header to get the address of the next hop, unless
+ * this is supplied by the caller in the *params* argument. The
+ * *plen* argument indicates the len of *params* and should be set
+ * to 0 if *params* is NULL.
*
* The *flags* argument is reserved and must be 0. The helper is
* currently only supported for tc BPF program types, and enabled
@@ -4906,6 +4910,16 @@ struct bpf_fib_lookup {
__u8 dmac[6]; /* ETH_ALEN */
};
+struct bpf_redir_neigh {
+ /* network family for lookup (AF_INET, AF_INET6) */
+ __u32 nh_family;
+ /* network address of nexthop; skips fib lookup to find gateway */
+ union {
+ __be32 ipv4_nh;
+ __u32 ipv6_nh[4]; /* in6_addr; network order */
+ };
+};
+
enum bpf_task_fd_type {
BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
BPF_FD_TYPE_TRACEPOINT, /* tp name */