diff options
Diffstat (limited to 'samples/bpf/parse_ldabs.c')
| -rw-r--r-- | samples/bpf/parse_ldabs.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/samples/bpf/parse_ldabs.c b/samples/bpf/parse_ldabs.c new file mode 100644 index 000000000..d17550198 --- /dev/null +++ b/samples/bpf/parse_ldabs.c @@ -0,0 +1,41 @@ +/* Copyright (c) 2016 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <linux/ip.h> +#include <linux/ipv6.h> +#include <linux/in.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <uapi/linux/bpf.h> +#include "bpf_helpers.h" + +#define DEFAULT_PKTGEN_UDP_PORT 9 +#define IP_MF 0x2000 +#define IP_OFFSET 0x1FFF + +static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff) +{ + return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off)) + & (IP_MF | IP_OFFSET); +} + +SEC("ldabs") +int handle_ingress(struct __sk_buff *skb) +{ + __u64 troff = ETH_HLEN + sizeof(struct iphdr); + + if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP) + return 0; + if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP || + load_byte(skb, ETH_HLEN) != 0x45) + return 0; + if (ip_is_fragment(skb, ETH_HLEN)) + return 0; + if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT) + return TC_ACT_SHOT; + return 0; +} +char _license[] SEC("license") = "GPL"; |