1
2
3#include <linux/sched.h>
4#include <linux/ptrace.h>
5#include <stdint.h>
6#include <stddef.h>
7#include <stdbool.h>
8#include <linux/bpf.h>
9#include <bpf/bpf_helpers.h>
10
11#define FUNCTION_NAME_LEN 64
12#define FILE_NAME_LEN 128
13#define TASK_COMM_LEN 16
14
15typedef struct {
16 int PyThreadState_frame;
17 int PyThreadState_thread;
18 int PyFrameObject_back;
19 int PyFrameObject_code;
20 int PyFrameObject_lineno;
21 int PyCodeObject_filename;
22 int PyCodeObject_name;
23 int String_data;
24 int String_size;
25} OffsetConfig;
26
27typedef struct {
28 uintptr_t current_state_addr;
29 uintptr_t tls_key_addr;
30 OffsetConfig offsets;
31 bool use_tls;
32} PidData;
33
34typedef struct {
35 uint32_t success;
36} Stats;
37
38typedef struct {
39 char name[FUNCTION_NAME_LEN];
40 char file[FILE_NAME_LEN];
41} Symbol;
42
43typedef struct {
44 uint32_t pid;
45 uint32_t tid;
46 char comm[TASK_COMM_LEN];
47 int32_t kernel_stack_id;
48 int32_t user_stack_id;
49 bool thread_current;
50 bool pthread_match;
51 bool stack_complete;
52 int16_t stack_len;
53 int32_t stack[STACK_MAX_LEN];
54
55 int has_meta;
56 int metadata;
57 char dummy_safeguard;
58} Event;
59
60
61typedef int pid_t;
62
63typedef struct {
64 void* f_back;
65 void* f_code;
66 void* co_filename;
67 void* co_name;
68} FrameData;
69
70#ifdef SUBPROGS
71__noinline
72#else
73__always_inline
74#endif
75static void *get_thread_state(void *tls_base, PidData *pidData)
76{
77 void* thread_state;
78 int key;
79
80 bpf_probe_read_user(&key, sizeof(key), (void*)(long)pidData->tls_key_addr);
81 bpf_probe_read_user(&thread_state, sizeof(thread_state),
82 tls_base + 0x310 + key * 0x10 + 0x08);
83 return thread_state;
84}
85
86static __always_inline bool get_frame_data(void *frame_ptr, PidData *pidData,
87 FrameData *frame, Symbol *symbol)
88{
89
90 bpf_probe_read_user(&frame->f_back,
91 sizeof(frame->f_back),
92 frame_ptr + pidData->offsets.PyFrameObject_back);
93 bpf_probe_read_user(&frame->f_code,
94 sizeof(frame->f_code),
95 frame_ptr + pidData->offsets.PyFrameObject_code);
96
97
98 if (!frame->f_code)
99 return false;
100 bpf_probe_read_user(&frame->co_filename,
101 sizeof(frame->co_filename),
102 frame->f_code + pidData->offsets.PyCodeObject_filename);
103 bpf_probe_read_user(&frame->co_name,
104 sizeof(frame->co_name),
105 frame->f_code + pidData->offsets.PyCodeObject_name);
106
107 if (frame->co_filename)
108 bpf_probe_read_user_str(&symbol->file,
109 sizeof(symbol->file),
110 frame->co_filename +
111 pidData->offsets.String_data);
112 if (frame->co_name)
113 bpf_probe_read_user_str(&symbol->name,
114 sizeof(symbol->name),
115 frame->co_name +
116 pidData->offsets.String_data);
117 return true;
118}
119
120struct {
121 __uint(type, BPF_MAP_TYPE_HASH);
122 __uint(max_entries, 1);
123 __type(key, int);
124 __type(value, PidData);
125} pidmap SEC(".maps");
126
127struct {
128 __uint(type, BPF_MAP_TYPE_HASH);
129 __uint(max_entries, 1);
130 __type(key, int);
131 __type(value, Event);
132} eventmap SEC(".maps");
133
134struct {
135 __uint(type, BPF_MAP_TYPE_HASH);
136 __uint(max_entries, 1);
137 __type(key, Symbol);
138 __type(value, int);
139} symbolmap SEC(".maps");
140
141struct {
142 __uint(type, BPF_MAP_TYPE_ARRAY);
143 __uint(max_entries, 1);
144 __type(key, int);
145 __type(value, Stats);
146} statsmap SEC(".maps");
147
148struct {
149 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
150 __uint(max_entries, 32);
151 __uint(key_size, sizeof(int));
152 __uint(value_size, sizeof(int));
153} perfmap SEC(".maps");
154
155struct {
156 __uint(type, BPF_MAP_TYPE_STACK_TRACE);
157 __uint(max_entries, 1000);
158 __uint(key_size, sizeof(int));
159 __uint(value_size, sizeof(long long) * 127);
160} stackmap SEC(".maps");
161
162#ifdef GLOBAL_FUNC
163__noinline
164#elif defined(SUBPROGS)
165static __noinline
166#else
167static __always_inline
168#endif
169int __on_event(struct bpf_raw_tracepoint_args *ctx)
170{
171 uint64_t pid_tgid = bpf_get_current_pid_tgid();
172 pid_t pid = (pid_t)(pid_tgid >> 32);
173 PidData* pidData = bpf_map_lookup_elem(&pidmap, &pid);
174 if (!pidData)
175 return 0;
176
177 int zero = 0;
178 Event* event = bpf_map_lookup_elem(&eventmap, &zero);
179 if (!event)
180 return 0;
181
182 event->pid = pid;
183
184 event->tid = (pid_t)pid_tgid;
185 bpf_get_current_comm(&event->comm, sizeof(event->comm));
186
187 event->user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
188 event->kernel_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
189
190 void* thread_state_current = (void*)0;
191 bpf_probe_read_user(&thread_state_current,
192 sizeof(thread_state_current),
193 (void*)(long)pidData->current_state_addr);
194
195 struct task_struct* task = (struct task_struct*)bpf_get_current_task();
196 void* tls_base = (void*)task;
197
198 void* thread_state = pidData->use_tls ? get_thread_state(tls_base, pidData)
199 : thread_state_current;
200 event->thread_current = thread_state == thread_state_current;
201
202 if (pidData->use_tls) {
203 uint64_t pthread_created;
204 uint64_t pthread_self;
205 bpf_probe_read_user(&pthread_self, sizeof(pthread_self),
206 tls_base + 0x10);
207
208 bpf_probe_read_user(&pthread_created,
209 sizeof(pthread_created),
210 thread_state +
211 pidData->offsets.PyThreadState_thread);
212 event->pthread_match = pthread_created == pthread_self;
213 } else {
214 event->pthread_match = 1;
215 }
216
217 if (event->pthread_match || !pidData->use_tls) {
218 void* frame_ptr;
219 FrameData frame;
220 Symbol sym = {};
221 int cur_cpu = bpf_get_smp_processor_id();
222
223 bpf_probe_read_user(&frame_ptr,
224 sizeof(frame_ptr),
225 thread_state +
226 pidData->offsets.PyThreadState_frame);
227
228 int32_t* symbol_counter = bpf_map_lookup_elem(&symbolmap, &sym);
229 if (symbol_counter == NULL)
230 return 0;
231#ifdef NO_UNROLL
232#pragma clang loop unroll(disable)
233#else
234#pragma clang loop unroll(full)
235#endif
236
237 for (int i = 0; i < STACK_MAX_LEN; ++i) {
238 if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
239 int32_t new_symbol_id = *symbol_counter * 64 + cur_cpu;
240 int32_t *symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
241 if (!symbol_id) {
242 bpf_map_update_elem(&symbolmap, &sym, &zero, 0);
243 symbol_id = bpf_map_lookup_elem(&symbolmap, &sym);
244 if (!symbol_id)
245 return 0;
246 }
247 if (*symbol_id == new_symbol_id)
248 (*symbol_counter)++;
249 event->stack[i] = *symbol_id;
250 event->stack_len = i + 1;
251 frame_ptr = frame.f_back;
252 }
253 }
254 event->stack_complete = frame_ptr == NULL;
255 } else {
256 event->stack_complete = 1;
257 }
258
259 Stats* stats = bpf_map_lookup_elem(&statsmap, &zero);
260 if (stats)
261 stats->success++;
262
263 event->has_meta = 0;
264 bpf_perf_event_output(ctx, &perfmap, 0, event, offsetof(Event, metadata));
265 return 0;
266}
267
268SEC("raw_tracepoint/kfree_skb")
269int on_event(struct bpf_raw_tracepoint_args* ctx)
270{
271 int i, ret = 0;
272 ret |= __on_event(ctx);
273 ret |= __on_event(ctx);
274 ret |= __on_event(ctx);
275 ret |= __on_event(ctx);
276 ret |= __on_event(ctx);
277 return ret;
278}
279
280char _license[] SEC("license") = "GPL";
281
