103 lines
2.8 KiB
C
103 lines
2.8 KiB
C
#include <stdbool.h>
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#include <linux/bpf.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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//#include <linux/tcp.h>
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//#include <linux/udp.h>
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#include <linux/pkt_cls.h>
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#include "bpf_endian.h"
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#include "bpf_helpers.h"
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 2);
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__uint(pinning, LIBBPF_PIN_BY_NAME);
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} tc_params_map SEC(".maps");
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static __always_inline bool is_lan_ip(__be32 addr) {
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if (addr == 0xffffffff)
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return true;
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__u8 fist = (__u8)(addr & 0xff);
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if (fist == 127 || fist == 10)
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return true;
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__u8 second = (__u8)((addr >> 8) & 0xff);
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if (fist == 172 && second >= 16 && second <= 31)
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return true;
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if (fist == 192 && second == 168)
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return true;
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return false;
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}
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SEC("tc_mihomo_redirect_to_tun")
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int tc_tun_func(struct __sk_buff *skb) {
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void *data = (void *)(long)skb->data;
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void *data_end = (void *)(long)skb->data_end;
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struct ethhdr *eth = data;
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if ((void *)(eth + 1) > data_end)
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return TC_ACT_OK;
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if (eth->h_proto == bpf_htons(ETH_P_ARP))
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return TC_ACT_OK;
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__u32 key = 0, *mihomo_mark, *tun_ifindex;
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mihomo_mark = bpf_map_lookup_elem(&tc_params_map, &key);
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if (!mihomo_mark)
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return TC_ACT_OK;
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if (skb->mark == *mihomo_mark)
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return TC_ACT_OK;
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if (eth->h_proto == bpf_htons(ETH_P_IP)) {
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struct iphdr *iph = (struct iphdr *)(eth + 1);
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if ((void *)(iph + 1) > data_end)
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return TC_ACT_OK;
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if (iph->protocol == IPPROTO_ICMP)
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return TC_ACT_OK;
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__be32 daddr = iph->daddr;
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if (is_lan_ip(daddr))
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return TC_ACT_OK;
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// if (iph->protocol == IPPROTO_TCP) {
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// struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
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// if ((void *)(tcph + 1) > data_end)
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// return TC_ACT_OK;
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//
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// __u16 source = bpf_ntohs(tcph->source);
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// if (source == 22 || source == 80 || source == 443 || source == 8080 || source == 8443 || source == 9090 || (source >= 7890 && source <= 7895))
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// return TC_ACT_OK;
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// } else if (iph->protocol == IPPROTO_UDP) {
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// struct udphdr *udph = (struct udphdr *)(iph + 1);
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// if ((void *)(udph + 1) > data_end)
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// return TC_ACT_OK;
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//
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// __u16 source = bpf_ntohs(udph->source);
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// if (source == 53 || (source >= 135 && source <= 139))
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// return TC_ACT_OK;
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// }
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}
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key = 1;
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tun_ifindex = bpf_map_lookup_elem(&tc_params_map, &key);
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if (!tun_ifindex)
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return TC_ACT_OK;
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//return bpf_redirect(*tun_ifindex, BPF_F_INGRESS); // __bpf_rx_skb
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return bpf_redirect(*tun_ifindex, 0); // __bpf_tx_skb / __dev_xmit_skb
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}
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char _license[] SEC("license") = "GPL";
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