1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3 #include "vmlinux.h"
4 #include <bpf/bpf_helpers.h>
5 #include <bpf/bpf_tracing.h>
6 #include <bpf/bpf_core_read.h>
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
10 __uint(map_flags, BPF_F_NO_PREALLOC);
11 __type(key, int);
12 __type(value, long);
13 } enter_id SEC(".maps");
14
15 #define IFNAMSIZ 16
16
17 int ifindex, ingress_ifindex;
18 char name[IFNAMSIZ];
19 unsigned int inum;
20 unsigned int meta_len, frag0_len, kskb_len, kskb2_len;
21
22 void *bpf_cast_to_kern_ctx(void *) __ksym;
23 void *bpf_rdonly_cast(void *, __u32) __ksym;
24
25 SEC("?xdp")
md_xdp(struct xdp_md * ctx)26 int md_xdp(struct xdp_md *ctx)
27 {
28 struct xdp_buff *kctx = bpf_cast_to_kern_ctx(ctx);
29 struct net_device *dev;
30
31 dev = kctx->rxq->dev;
32 ifindex = dev->ifindex;
33 inum = dev->nd_net.net->ns.inum;
34 __builtin_memcpy(name, dev->name, IFNAMSIZ);
35 ingress_ifindex = ctx->ingress_ifindex;
36 return XDP_PASS;
37 }
38
39 SEC("?tc")
md_skb(struct __sk_buff * skb)40 int md_skb(struct __sk_buff *skb)
41 {
42 struct sk_buff *kskb = bpf_cast_to_kern_ctx(skb);
43 struct skb_shared_info *shared_info;
44 struct sk_buff *kskb2;
45
46 kskb_len = kskb->len;
47
48 /* Simulate the following kernel macro:
49 * #define skb_shinfo(SKB) ((struct skb_shared_info *)(skb_end_pointer(SKB)))
50 */
51 shared_info = bpf_rdonly_cast(kskb->head + kskb->end,
52 bpf_core_type_id_kernel(struct skb_shared_info));
53 meta_len = shared_info->meta_len;
54 frag0_len = shared_info->frag_list->len;
55
56 /* kskb2 should be equal to kskb */
57 kskb2 = bpf_rdonly_cast(kskb, bpf_core_type_id_kernel(struct sk_buff));
58 kskb2_len = kskb2->len;
59 return 0;
60 }
61
62 SEC("?tp_btf/sys_enter")
BPF_PROG(untrusted_ptr,struct pt_regs * regs,long id)63 int BPF_PROG(untrusted_ptr, struct pt_regs *regs, long id)
64 {
65 struct task_struct *task, *task_dup;
66
67 task = bpf_get_current_task_btf();
68 task_dup = bpf_rdonly_cast(task, bpf_core_type_id_kernel(struct task_struct));
69 (void)bpf_task_storage_get(&enter_id, task_dup, 0, 0);
70 return 0;
71 }
72
73 SEC("?tracepoint/syscalls/sys_enter_nanosleep")
kctx_u64(void * ctx)74 int kctx_u64(void *ctx)
75 {
76 u64 *kctx = bpf_rdonly_cast(ctx, bpf_core_type_id_kernel(u64));
77
78 (void)kctx;
79 return 0;
80 }
81
82 char _license[] SEC("license") = "GPL";
83