Clash.Meta/component/ebpf/bpf/tc.c

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2.8 KiB
C
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2022-07-29 09:08:35 +08:00
#include <stdbool.h>
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/in.h>
//#include <linux/tcp.h>
//#include <linux/udp.h>
#include <linux/pkt_cls.h>
#include "bpf_endian.h"
#include "bpf_helpers.h"
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, __u32);
__type(value, __u32);
__uint(max_entries, 2);
__uint(pinning, LIBBPF_PIN_BY_NAME);
} tc_params_map SEC(".maps");
static __always_inline bool is_lan_ip(__be32 addr) {
if (addr == 0xffffffff)
return true;
__u8 fist = (__u8)(addr & 0xff);
if (fist == 127 || fist == 10)
return true;
__u8 second = (__u8)((addr >> 8) & 0xff);
if (fist == 172 && second >= 16 && second <= 31)
return true;
if (fist == 192 && second == 168)
return true;
return false;
}
SEC("tc_clash_redirect_to_tun")
int tc_tun_func(struct __sk_buff *skb) {
void *data = (void *)(long)skb->data;
void *data_end = (void *)(long)skb->data_end;
struct ethhdr *eth = data;
if ((void *)(eth + 1) > data_end)
return TC_ACT_OK;
if (eth->h_proto == bpf_htons(ETH_P_ARP))
return TC_ACT_OK;
__u32 key = 0, *clash_mark, *tun_ifindex;
clash_mark = bpf_map_lookup_elem(&tc_params_map, &key);
if (!clash_mark)
return TC_ACT_OK;
if (skb->mark == *clash_mark)
return TC_ACT_OK;
if (eth->h_proto == bpf_htons(ETH_P_IP)) {
struct iphdr *iph = (struct iphdr *)(eth + 1);
if ((void *)(iph + 1) > data_end)
return TC_ACT_OK;
if (iph->protocol == IPPROTO_ICMP)
return TC_ACT_OK;
__be32 daddr = iph->daddr;
if (is_lan_ip(daddr))
return TC_ACT_OK;
// if (iph->protocol == IPPROTO_TCP) {
// struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
// if ((void *)(tcph + 1) > data_end)
// return TC_ACT_OK;
//
// __u16 source = bpf_ntohs(tcph->source);
// if (source == 22 || source == 80 || source == 443 || source == 8080 || source == 8443 || source == 9090 || (source >= 7890 && source <= 7895))
// return TC_ACT_OK;
// } else if (iph->protocol == IPPROTO_UDP) {
// struct udphdr *udph = (struct udphdr *)(iph + 1);
// if ((void *)(udph + 1) > data_end)
// return TC_ACT_OK;
//
// __u16 source = bpf_ntohs(udph->source);
// if (source == 53 || (source >= 135 && source <= 139))
// return TC_ACT_OK;
// }
}
key = 1;
tun_ifindex = bpf_map_lookup_elem(&tc_params_map, &key);
if (!tun_ifindex)
return TC_ACT_OK;
//return bpf_redirect(*tun_ifindex, BPF_F_INGRESS); // __bpf_rx_skb
return bpf_redirect(*tun_ifindex, 0); // __bpf_tx_skb / __dev_xmit_skb
}
char _license[] SEC("license") = "GPL";