diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/test_lwt_reroute.c')
-rw-r--r-- | tools/testing/selftests/bpf/progs/test_lwt_reroute.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_lwt_reroute.c b/tools/testing/selftests/bpf/progs/test_lwt_reroute.c new file mode 100644 index 0000000000..1dc6435192 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_lwt_reroute.c @@ -0,0 +1,36 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <inttypes.h> +#include <linux/bpf.h> +#include <bpf/bpf_endian.h> +#include <bpf/bpf_helpers.h> +#include <linux/if_ether.h> +#include <linux/ip.h> + +/* This function extracts the last byte of the daddr, and uses it + * as output dev index. + */ +SEC("lwt_xmit") +int test_lwt_reroute(struct __sk_buff *skb) +{ + struct iphdr *iph = NULL; + void *start = (void *)(long)skb->data; + void *end = (void *)(long)skb->data_end; + + /* set mark at most once */ + if (skb->mark != 0) + return BPF_OK; + + if (start + sizeof(*iph) > end) + return BPF_DROP; + + iph = (struct iphdr *)start; + skb->mark = bpf_ntohl(iph->daddr) & 0xff; + + /* do not reroute x.x.x.0 packets */ + if (skb->mark == 0) + return BPF_OK; + + return BPF_LWT_REROUTE; +} + +char _license[] SEC("license") = "GPL"; |