1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bpf.h> 3 #include <linux/pkt_cls.h> 4 #include <linux/if_ether.h> 5 #include <linux/ipv6.h> 6 #include <linux/in6.h> 7 #include <bpf/bpf_endian.h> 8 #include <bpf/bpf_helpers.h> 9 10 #define TC_ACT_OK 0 11 #define ETH_P_IPV6 0x86DD 12 13 #define ctx_ptr(field) ((void *)(long)(field)) 14 15 #define v6_p64_equal(a, b) (a.s6_addr32[0] == b.s6_addr32[0] && \ 16 a.s6_addr32[1] == b.s6_addr32[1]) 17 18 volatile __u32 netkit_ifindex; 19 volatile __u8 ipv6_prefix[16]; 20 21 SEC("tc/ingress") 22 int tc_redirect_peer(struct __sk_buff *skb) 23 { 24 void *data_end = ctx_ptr(skb->data_end); 25 void *data = ctx_ptr(skb->data); 26 struct in6_addr *peer_addr; 27 struct ipv6hdr *ip6h; 28 struct ethhdr *eth; 29 30 peer_addr = (struct in6_addr *)ipv6_prefix; 31 32 if (skb->protocol != bpf_htons(ETH_P_IPV6)) 33 return TC_ACT_OK; 34 35 eth = data; 36 if ((void *)(eth + 1) > data_end) 37 return TC_ACT_OK; 38 39 ip6h = data + sizeof(struct ethhdr); 40 if ((void *)(ip6h + 1) > data_end) 41 return TC_ACT_OK; 42 43 if (!v6_p64_equal(ip6h->daddr, (*peer_addr))) 44 return TC_ACT_OK; 45 46 return bpf_redirect_peer(netkit_ifindex, 0); 47 } 48 49 char __license[] SEC("license") = "GPL"; 50