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![Daniel T. Lee](/assets/img/avatar_default.png)
Since, the new syntax of BTF-defined map has been introduced,
the syntax for using maps under samples directory are mixed up.
For example, some are already using the new syntax, and some are using
existing syntax by calling them as 'legacy'.
As stated at commit abd29c9314
("libbpf: allow specifying map
definitions using BTF"), the BTF-defined map has more compatablility
with extending supported map definition features.
The commit doesn't replace all of the map to new BTF-defined map,
because some of the samples still use bpf_load instead of libbpf, which
can't properly create BTF-defined map.
This will only updates the samples which uses libbpf API for loading bpf
program. (ex. bpf_prog_load_xattr)
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
237 lines
5.6 KiB
C
237 lines
5.6 KiB
C
/* Copyright (c) 2016 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program shows how to use bpf_xdp_adjust_head() by
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* encapsulating the incoming packet in an IPv4/v6 header
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* and then XDP_TX it out.
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*/
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#define KBUILD_MODNAME "foo"
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#include <uapi/linux/bpf.h>
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#include <linux/in.h>
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#include <linux/if_ether.h>
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#include <linux/if_packet.h>
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#include <linux/if_vlan.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include "bpf_helpers.h"
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#include "xdp_tx_iptunnel_common.h"
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struct {
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__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
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__type(key, __u32);
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__type(value, __u64);
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__uint(max_entries, 256);
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} rxcnt SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__type(key, struct vip);
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__type(value, struct iptnl_info);
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__uint(max_entries, MAX_IPTNL_ENTRIES);
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} vip2tnl SEC(".maps");
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static __always_inline void count_tx(u32 protocol)
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{
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u64 *rxcnt_count;
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rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol);
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if (rxcnt_count)
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*rxcnt_count += 1;
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}
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static __always_inline int get_dport(void *trans_data, void *data_end,
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u8 protocol)
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{
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struct tcphdr *th;
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struct udphdr *uh;
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switch (protocol) {
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case IPPROTO_TCP:
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th = (struct tcphdr *)trans_data;
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if (th + 1 > data_end)
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return -1;
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return th->dest;
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case IPPROTO_UDP:
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uh = (struct udphdr *)trans_data;
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if (uh + 1 > data_end)
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return -1;
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return uh->dest;
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default:
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return 0;
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}
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}
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static __always_inline void set_ethhdr(struct ethhdr *new_eth,
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const struct ethhdr *old_eth,
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const struct iptnl_info *tnl,
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__be16 h_proto)
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{
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memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source));
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memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest));
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new_eth->h_proto = h_proto;
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}
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static __always_inline int handle_ipv4(struct xdp_md *xdp)
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{
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void *data_end = (void *)(long)xdp->data_end;
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void *data = (void *)(long)xdp->data;
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struct iptnl_info *tnl;
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struct ethhdr *new_eth;
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struct ethhdr *old_eth;
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struct iphdr *iph = data + sizeof(struct ethhdr);
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u16 *next_iph_u16;
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u16 payload_len;
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struct vip vip = {};
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int dport;
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u32 csum = 0;
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int i;
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if (iph + 1 > data_end)
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return XDP_DROP;
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dport = get_dport(iph + 1, data_end, iph->protocol);
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if (dport == -1)
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return XDP_DROP;
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vip.protocol = iph->protocol;
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vip.family = AF_INET;
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vip.daddr.v4 = iph->daddr;
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vip.dport = dport;
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payload_len = ntohs(iph->tot_len);
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tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
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/* It only does v4-in-v4 */
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if (!tnl || tnl->family != AF_INET)
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return XDP_PASS;
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/* The vip key is found. Add an IP header and send it out */
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if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr)))
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return XDP_DROP;
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data = (void *)(long)xdp->data;
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data_end = (void *)(long)xdp->data_end;
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new_eth = data;
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iph = data + sizeof(*new_eth);
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old_eth = data + sizeof(*iph);
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if (new_eth + 1 > data_end ||
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old_eth + 1 > data_end ||
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iph + 1 > data_end)
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return XDP_DROP;
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set_ethhdr(new_eth, old_eth, tnl, htons(ETH_P_IP));
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iph->version = 4;
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iph->ihl = sizeof(*iph) >> 2;
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iph->frag_off = 0;
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iph->protocol = IPPROTO_IPIP;
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iph->check = 0;
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iph->tos = 0;
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iph->tot_len = htons(payload_len + sizeof(*iph));
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iph->daddr = tnl->daddr.v4;
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iph->saddr = tnl->saddr.v4;
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iph->ttl = 8;
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next_iph_u16 = (u16 *)iph;
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#pragma clang loop unroll(full)
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for (i = 0; i < sizeof(*iph) >> 1; i++)
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csum += *next_iph_u16++;
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iph->check = ~((csum & 0xffff) + (csum >> 16));
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count_tx(vip.protocol);
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return XDP_TX;
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}
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static __always_inline int handle_ipv6(struct xdp_md *xdp)
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{
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void *data_end = (void *)(long)xdp->data_end;
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void *data = (void *)(long)xdp->data;
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struct iptnl_info *tnl;
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struct ethhdr *new_eth;
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struct ethhdr *old_eth;
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struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);
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__u16 payload_len;
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struct vip vip = {};
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int dport;
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if (ip6h + 1 > data_end)
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return XDP_DROP;
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dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr);
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if (dport == -1)
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return XDP_DROP;
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vip.protocol = ip6h->nexthdr;
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vip.family = AF_INET6;
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memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr));
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vip.dport = dport;
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payload_len = ip6h->payload_len;
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tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
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/* It only does v6-in-v6 */
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if (!tnl || tnl->family != AF_INET6)
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return XDP_PASS;
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/* The vip key is found. Add an IP header and send it out */
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if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr)))
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return XDP_DROP;
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data = (void *)(long)xdp->data;
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data_end = (void *)(long)xdp->data_end;
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new_eth = data;
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ip6h = data + sizeof(*new_eth);
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old_eth = data + sizeof(*ip6h);
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if (new_eth + 1 > data_end ||
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old_eth + 1 > data_end ||
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ip6h + 1 > data_end)
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return XDP_DROP;
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set_ethhdr(new_eth, old_eth, tnl, htons(ETH_P_IPV6));
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ip6h->version = 6;
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ip6h->priority = 0;
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memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));
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ip6h->payload_len = htons(ntohs(payload_len) + sizeof(*ip6h));
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ip6h->nexthdr = IPPROTO_IPV6;
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ip6h->hop_limit = 8;
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memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6));
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memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6));
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count_tx(vip.protocol);
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return XDP_TX;
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}
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SEC("xdp_tx_iptunnel")
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int _xdp_tx_iptunnel(struct xdp_md *xdp)
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{
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void *data_end = (void *)(long)xdp->data_end;
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void *data = (void *)(long)xdp->data;
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struct ethhdr *eth = data;
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__u16 h_proto;
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if (eth + 1 > data_end)
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return XDP_DROP;
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h_proto = eth->h_proto;
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if (h_proto == htons(ETH_P_IP))
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return handle_ipv4(xdp);
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else if (h_proto == htons(ETH_P_IPV6))
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return handle_ipv6(xdp);
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else
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return XDP_PASS;
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}
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char _license[] SEC("license") = "GPL";
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