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") 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") 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") 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") 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