1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3 #include <bpf/bpf_helpers.h>
4 #include <bpf/bpf_endian.h>
5
6 #include <linux/ip.h>
7 #include <linux/in.h>
8 #include <linux/if_ether.h>
9 #include <linux/pkt_cls.h>
10 #include <stdbool.h>
11
12 int lookup_status;
13 bool test_xdp;
14 bool tcp_skc;
15
16 #define CUR_NS BPF_F_CURRENT_NETNS
17
18 static void socket_lookup(void *ctx, void *data_end, void *data)
19 {
20 struct ethhdr *eth = data;
21 struct bpf_sock_tuple *tp;
22 struct bpf_sock *sk;
23 struct iphdr *iph;
24 int tplen;
25
26 if (eth + 1 > data_end)
27 return;
28
29 if (eth->h_proto != bpf_htons(ETH_P_IP))
30 return;
31
32 iph = (struct iphdr *)(eth + 1);
33 if (iph + 1 > data_end)
34 return;
35
36 tp = (struct bpf_sock_tuple *)&iph->saddr;
37 tplen = sizeof(tp->ipv4);
38 if ((void *)tp + tplen > data_end)
39 return;
40
41 switch (iph->protocol) {
42 case IPPROTO_TCP:
43 if (tcp_skc)
44 sk = bpf_skc_lookup_tcp(ctx, tp, tplen, CUR_NS, 0);
45 else
46 sk = bpf_sk_lookup_tcp(ctx, tp, tplen, CUR_NS, 0);
47 break;
48 case IPPROTO_UDP:
49 sk = bpf_sk_lookup_udp(ctx, tp, tplen, CUR_NS, 0);
50 break;
51 default:
52 return;
53 }
54
55 lookup_status = 0;
56
57 if (sk) {
58 bpf_sk_release(sk);
59 lookup_status = 1;
60 }
61 }
62
63 SEC("tc")
64 int tc_socket_lookup(struct __sk_buff *skb)
65 {
66 void *data_end = (void *)(long)skb->data_end;
67 void *data = (void *)(long)skb->data;
68
69 if (test_xdp)
70 return TC_ACT_UNSPEC;
71
72 socket_lookup(skb, data_end, data);
73 return TC_ACT_UNSPEC;
74 }
75
76 SEC("xdp")
77 int xdp_socket_lookup(struct xdp_md *xdp)
78 {
79 void *data_end = (void *)(long)xdp->data_end;
80 void *data = (void *)(long)xdp->data;
81
82 if (!test_xdp)
83 return XDP_PASS;
84
85 socket_lookup(xdp, data_end, data);
86 return XDP_PASS;
87 }
88
89 char _license[] SEC("license") = "GPL";
90
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