LXR linux/tools/testing/selftests/bpf/progs/test_lwt_ip

   1// SPDX-License-Identifier: GPL-2.0
   2#include <stddef.h>
   3#include <string.h>
   4#include <linux/bpf.h>
   5#include <linux/ip.h>
   6#include <linux/ipv6.h>
   7#include <bpf/bpf_helpers.h>
   8#include <bpf/bpf_endian.h>
   9
  10struct grehdr {
  11        __be16 flags;
  12        __be16 protocol;
  13};
  14
  15SEC("encap_gre")
  16int bpf_lwt_encap_gre(struct __sk_buff *skb)
  17{
  18        struct encap_hdr {
  19                struct iphdr iph;
  20                struct grehdr greh;
  21        } hdr;
  22        int err;
  23
  24        memset(&hdr, 0, sizeof(struct encap_hdr));
  25
  26        hdr.iph.ihl = 5;
  27        hdr.iph.version = 4;
  28        hdr.iph.ttl = 0x40;
  29        hdr.iph.protocol = 47;  /* IPPROTO_GRE */
  30#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  31        hdr.iph.saddr = 0x640110ac;  /* 172.16.1.100 */
  32        hdr.iph.daddr = 0x641010ac;  /* 172.16.16.100 */
  33#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
  34        hdr.iph.saddr = 0xac100164;  /* 172.16.1.100 */
  35        hdr.iph.daddr = 0xac101064;  /* 172.16.16.100 */
  36#else
  37#error "Fix your compiler's __BYTE_ORDER__?!"
  38#endif
  39        hdr.iph.tot_len = bpf_htons(skb->len + sizeof(struct encap_hdr));
  40
  41        hdr.greh.protocol = skb->protocol;
  42
  43        err = bpf_lwt_push_encap(skb, BPF_LWT_ENCAP_IP, &hdr,
  44                                 sizeof(struct encap_hdr));
  45        if (err)
  46                return BPF_DROP;
  47
  48        return BPF_LWT_REROUTE;
  49}
  50
  51SEC("encap_gre6")
  52int bpf_lwt_encap_gre6(struct __sk_buff *skb)
  53{
  54        struct encap_hdr {
  55                struct ipv6hdr ip6hdr;
  56                struct grehdr greh;
  57        } hdr;
  58        int err;
  59
  60        memset(&hdr, 0, sizeof(struct encap_hdr));
  61
  62        hdr.ip6hdr.version = 6;
  63        hdr.ip6hdr.payload_len = bpf_htons(skb->len + sizeof(struct grehdr));
  64        hdr.ip6hdr.nexthdr = 47;  /* IPPROTO_GRE */
  65        hdr.ip6hdr.hop_limit = 0x40;
  66        /* fb01::1 */
  67        hdr.ip6hdr.saddr.s6_addr[0] = 0xfb;
  68        hdr.ip6hdr.saddr.s6_addr[1] = 1;
  69        hdr.ip6hdr.saddr.s6_addr[15] = 1;
  70        /* fb10::1 */
  71        hdr.ip6hdr.daddr.s6_addr[0] = 0xfb;
  72        hdr.ip6hdr.daddr.s6_addr[1] = 0x10;
  73        hdr.ip6hdr.daddr.s6_addr[15] = 1;
  74
  75        hdr.greh.protocol = skb->protocol;
  76
  77        err = bpf_lwt_push_encap(skb, BPF_LWT_ENCAP_IP, &hdr,
  78                                 sizeof(struct encap_hdr));
  79        if (err)
  80                return BPF_DROP;
  81
  82        return BPF_LWT_REROUTE;
  83}
  84
  85char _license[] SEC("license") = "GPL";
  86