diff options
Diffstat (limited to 'samples/bpf/parse_simple.c')
| -rw-r--r-- | samples/bpf/parse_simple.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/samples/bpf/parse_simple.c b/samples/bpf/parse_simple.c new file mode 100644 index 000000000..10af53d33 --- /dev/null +++ b/samples/bpf/parse_simple.c @@ -0,0 +1,49 @@ +/* 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. + */ +#define KBUILD_MODNAME "foo" +#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 <net/ip.h> +#include "bpf_helpers.h" + +#define DEFAULT_PKTGEN_UDP_PORT 9 + +/* copy of 'struct ethhdr' without __packed */ +struct eth_hdr { + unsigned char h_dest[ETH_ALEN]; + unsigned char h_source[ETH_ALEN]; + unsigned short h_proto; +}; + +SEC("simple") +int handle_ingress(struct __sk_buff *skb) +{ + void *data = (void *)(long)skb->data; + struct eth_hdr *eth = data; + struct iphdr *iph = data + sizeof(*eth); + struct udphdr *udp = data + sizeof(*eth) + sizeof(*iph); + void *data_end = (void *)(long)skb->data_end; + + /* single length check */ + if (data + sizeof(*eth) + sizeof(*iph) + sizeof(*udp) > data_end) + return 0; + + if (eth->h_proto != htons(ETH_P_IP)) + return 0; + if (iph->protocol != IPPROTO_UDP || iph->ihl != 5) + return 0; + if (ip_is_fragment(iph)) + return 0; + if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT)) + return TC_ACT_SHOT; + return 0; +} +char _license[] SEC("license") = "GPL"; |