diff options
| author | Jesper Dangaard Brouer | 2019-08-08 18:17:42 +0200 |
|---|---|---|
| committer | Daniel Borkmann | 2019-08-09 18:05:03 +0200 |
| commit | a32a32cb26eb6291125e4eb49b569874ca9a53b5 (patch) | |
| tree | c581f37cf8c26549b17f14eb81757d18562a182d /samples/bpf/xdp_fwd_kern.c | |
| parent | 3783d43752eab247ed296ac8d5022484ed969151 (diff) | |
samples/bpf: make xdp_fwd more practically usable via devmap lookup
This address the TODO in samples/bpf/xdp_fwd_kern.c, which points out
that the chosen egress index should be checked for existence in the
devmap. This can now be done via taking advantage of Toke's work in
commit 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF").
This change makes xdp_fwd more practically usable, as this allows for
a mixed environment, where IP-forwarding fallback to network stack, if
the egress device isn't configured to use XDP.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'samples/bpf/xdp_fwd_kern.c')
| -rw-r--r-- | samples/bpf/xdp_fwd_kern.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/samples/bpf/xdp_fwd_kern.c b/samples/bpf/xdp_fwd_kern.c index e6ffc4ea06f4..a43d6953c054 100644 --- a/samples/bpf/xdp_fwd_kern.c +++ b/samples/bpf/xdp_fwd_kern.c @@ -104,13 +104,18 @@ static __always_inline int xdp_fwd_flags(struct xdp_md *ctx, u32 flags) rc = bpf_fib_lookup(ctx, &fib_params, sizeof(fib_params), flags); - /* verify egress index has xdp support - * TO-DO bpf_map_lookup_elem(&tx_port, &key) fails with - * cannot pass map_type 14 into func bpf_map_lookup_elem#1: - * NOTE: without verification that egress index supports XDP - * forwarding packets are dropped. - */ if (rc == 0) { + /* Verify egress index has been configured as TX-port. + * (Note: User can still have inserted an egress ifindex that + * doesn't support XDP xmit, which will result in packet drops). + * + * Note: lookup in devmap supported since 0cdbb4b09a0. + * If not supported will fail with: + * cannot pass map_type 14 into func bpf_map_lookup_elem#1: + */ + if (!bpf_map_lookup_elem(&xdp_tx_ports, &fib_params.ifindex)) + return XDP_PASS; + if (h_proto == htons(ETH_P_IP)) ip_decrease_ttl(iph); else if (h_proto == htons(ETH_P_IPV6)) |