trace: Add four generic circuit tracepoints

Signed-off-by: David Goulet <dgoulet@torproject.org>

src/core/or/circuitlist.c

@@ -65,6 +65,7 @@
 #include "core/or/circuitpadding.h"
 #include "core/or/crypt_path.h"
 #include "core/or/extendinfo.h"
+#include "core/or/trace_probes_circuit.h"
 #include "core/mainloop/connection.h"
 #include "app/config/config.h"
 #include "core/or/connection_edge.h"
@@ -99,6 +100,7 @@
 #include "lib/compress/compress_zlib.h"
 #include "lib/compress/compress_zstd.h"
 #include "lib/buf/buffers.h"
+#include "lib/trace/events.h"
 
 #include "core/or/ocirc_event.h"
 
@@ -565,6 +567,8 @@ circuit_set_state(circuit_t *circ, uint8_t state)
   }
   if (state == CIRCUIT_STATE_GUARD_WAIT || state == CIRCUIT_STATE_OPEN)
     tor_assert(!circ->n_chan_create_cell);
+
+  tor_trace(circuit, change_state, circ, circ->state, state);
   circ->state = state;
   if (CIRCUIT_IS_ORIGIN(circ))
     circuit_state_publish(circ);
@@ -1253,6 +1257,10 @@ circuit_free_(circuit_t *circ)
   /* Clear all dangling handle references. */
   circuit_handles_clear(circ);
 
+  /* Tracepoint. Data within the circuit object is recorded so do this before
+   * the actual memory free. */
+  tor_trace(circuit, free, circ);
+
   if (should_free) {
     memwipe(mem, 0xAA, memlen); /* poison memory */
     tor_free(mem);
@@ -2275,6 +2283,7 @@ circuit_mark_for_close_, (circuit_t *circ, int reason, int line,
            CIRCUIT_IS_ORIGIN(circ) ?
               TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0,
            file, line, orig_reason, reason);
+  tor_trace(circuit, mark_for_close, circ);
 }
 
 /** Called immediately before freeing a marked circuit <b>circ</b> from

src/core/or/circuituse.c

@@ -3144,6 +3144,7 @@ circuit_change_purpose(circuit_t *circ, uint8_t new_purpose)
 
   old_purpose = circ->purpose;
   circ->purpose = new_purpose;
+  tor_trace(circuit, change_purpose, circ, old_purpose, new_purpose);
 
   if (CIRCUIT_IS_ORIGIN(circ)) {
     control_event_circuit_purpose_changed(TO_ORIGIN_CIRCUIT(circ),

src/core/or/trace_probes_circuit.h

@@ -163,6 +163,60 @@ TRACEPOINT_EVENT_INSTANCE(tor_circuit, origin_circuit_t_class, idle_timeout,
   TP_ARGS(const origin_circuit_t *, circ)
 )
 
+/*
+ * General circuit events.
+ */
+
+TRACEPOINT_EVENT(tor_circuit, free,
+  TP_ARGS(const circuit_t *, circ),
+  TP_FIELDS(
+    ctf_integer(uint32_t, circ_id,
+                (CIRCUIT_IS_ORIGIN(circ) ?
+                 TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0))
+    ctf_enum(tor_circuit, purpose, int, purpose, circ->purpose)
+    ctf_enum(tor_circuit, state, int, state, circ->state)
+  )
+)
+
+TRACEPOINT_EVENT(tor_circuit, mark_for_close,
+  TP_ARGS(const circuit_t *, circ),
+  TP_FIELDS(
+    ctf_integer(uint32_t, circ_id,
+                (CIRCUIT_IS_ORIGIN(circ) ?
+                 TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0))
+    ctf_enum(tor_circuit, purpose, int, purpose, circ->purpose)
+    ctf_enum(tor_circuit, state, int, state, circ->state)
+    ctf_enum(tor_circuit, end_reason, int, close_reason,
+             circ->marked_for_close_reason)
+    ctf_enum(tor_circuit, end_reason, int, orig_close_reason,
+             circ->marked_for_close_orig_reason)
+  )
+)
+
+TRACEPOINT_EVENT(tor_circuit, change_purpose,
+  TP_ARGS(const circuit_t *, circ, int, old_purpose, int, new_purpose),
+  TP_FIELDS(
+    ctf_integer(uint32_t, circ_id,
+                (CIRCUIT_IS_ORIGIN(circ) ?
+                 TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0))
+    ctf_enum(tor_circuit, state, int, state, circ->state)
+    ctf_enum(tor_circuit, purpose, int, purpose, old_purpose)
+    ctf_enum(tor_circuit, purpose, int, new, new_purpose)
+  )
+)
+
+TRACEPOINT_EVENT(tor_circuit, change_state,
+  TP_ARGS(const circuit_t *, circ, int, old_state, int, new_state),
+  TP_FIELDS(
+    ctf_integer(uint32_t, circ_id,
+                (CIRCUIT_IS_ORIGIN(circ) ?
+                 TO_ORIGIN_CIRCUIT(circ)->global_identifier : 0))
+    ctf_enum(tor_circuit, purpose, int, purpose, circ->purpose)
+    ctf_enum(tor_circuit, state, int, old, old_state)
+    ctf_enum(tor_circuit, state, int, new, new_state)
+  )
+)
+
 #endif /* TOR_TRACE_PROBES_CIRCUIT_H */
 
 /* Must be include after the probes declaration. */