mirror of
https://github.com/xdp-project/bpf-examples.git
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583f7a213f
Makes sure the ethertype is set correctly depending on the type of encapsulation. Fixes #2. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
76 lines
1.8 KiB
C
76 lines
1.8 KiB
C
#include <linux/bpf.h>
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#include <linux/in6.h>
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#include <bpf/bpf_helpers.h>
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#include <xdp/parsing_helpers.h>
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#include "encap.h"
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#ifdef IPV6
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#define OFFSET sizeof(struct ipv6hdr)
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#define ENCAP_TYPE BPF_F_ADJ_ROOM_ENCAP_L3_IPV6
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#else
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#define OFFSET sizeof(struct iphdr)
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#define ENCAP_TYPE BPF_F_ADJ_ROOM_ENCAP_L3_IPV4
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#endif
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#define AF_INET 2
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SEC("classifier") int tc_encap(struct __sk_buff *skb)
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{
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struct bpf_fib_lookup fib_params = {};
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volatile void *data, *data_end;
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size_t offset = OFFSET;
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int ret = BPF_DROP;
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struct ethhdr *eth;
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struct iphdr *iph;
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if (bpf_skb_adjust_room(skb, offset, BPF_ADJ_ROOM_MAC, ENCAP_TYPE))
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goto out;
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data = (void *)(long)skb->data;
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data_end = (void *)(long)skb->data_end;
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eth = (void *)data;
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#ifdef IPV6
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encap_ipv6(data, data_end);
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#else
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encap_ipv4(data, data_end);
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iph = (void *)(eth +1);
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if (iph +1 > data_end)
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goto out;
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fib_params.family = AF_INET;
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fib_params.tos = iph->tos;
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fib_params.l4_protocol = iph->protocol;
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fib_params.sport = 0;
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fib_params.dport = 0;
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fib_params.tot_len = bpf_ntohs(iph->tot_len);
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fib_params.ipv4_src = iph->saddr;
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fib_params.ipv4_dst = iph->daddr;
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fib_params.ifindex = skb->ingress_ifindex;
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ret = bpf_fib_lookup(skb, &fib_params, sizeof(fib_params), 0);
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if (ret == BPF_FIB_LKUP_RET_SUCCESS) {
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__builtin_memcpy(eth->h_dest, fib_params.dmac, ETH_ALEN);
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__builtin_memcpy(eth->h_source, fib_params.smac, ETH_ALEN);
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return bpf_redirect(fib_params.ifindex, 0);
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} else if (ret == BPF_FIB_LKUP_RET_NO_NEIGH) {
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struct bpf_redir_neigh nh_params = {};
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nh_params.nh_family = fib_params.family;
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__builtin_memcpy(&nh_params.ipv6_nh, &fib_params.ipv6_dst,
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sizeof(nh_params.ipv6_nh));
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return bpf_redirect_neigh(fib_params.ifindex, &nh_params,
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sizeof(nh_params), 0);
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}
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#endif
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ret = BPF_OK;
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out:
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return ret;
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}
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char _license[] SEC("license") = "GPL";
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