tools/testing/selftests/bpf/progs/test_lwt_ip_encap.c

   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
  10 struct grehdr {
  11         __be16 flags;
  12         __be16 protocol;
  13 };
  14
  15 SEC("encap_gre")
  16 int 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
  51 SEC("encap_gre6")
  52 int 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
  85 char _license[] SEC("license") = "GPL";