nettrace: make some functions to monitor

Signed-off-by: Menglong Dong <imagedong@tencent.com>

Author: menglongdong

src/gen_trace.py

@@ -117,6 +117,9 @@ def get_arg_count(name):
             btf_data = btf_file.read()
     reg_text = f"'{name}' type_id=([0-9]+)"
     match = re.search(reg_text, btf_data)
+    if not match:
+        return 0
+
     type_id = match.group(1)
     match = re.search(f"\\[{type_id}\\].*vlen=([0-9]+)", btf_data)
     return match.group(1)
@@ -197,9 +200,16 @@ def gen_trace(trace, group, p_name):
         if 'skb' in trace or 'sock' in trace:
             arg_count = '0'
             if 'monitor' in trace:
-                trace['arg_count'] = get_arg_count(target)
-                arg_count = trace['arg_count']
-                fields_str += append_trace_field('arg_count', trace, 'raw')
+                if 'arg_count' not in trace:
+                    trace['arg_count'] = get_arg_count(target)
+                    arg_count = trace['arg_count']
+                else:
+                    arg_count = trace['arg_count']
+                if not arg_count:
+                    print(f"BTF not found for {target}, skip monitor", file=sys.stderr)
+                    trace['monitor'] = 0
+                else:
+                    fields_str += append_trace_field('arg_count', trace, 'raw')
             if 'skb' in trace:
                 skb_index = int(trace["skb"]) + 1
                 skb_str = f'\n\t.skb = {skb_index},'

src/trace.c

@@ -63,6 +63,9 @@ static void __print_trace_group(trace_group_t *group, int level)
 		if (status & TRACE_INVALID)
 			sprintf_end(buf, ",%s", PFMT_WARN_STR("invalid"));
 
+		if (trace->monitor)
+			sprintf_end(buf, ",%s", PFMT_WARN_STR("monitor"));
+
 		/* skip the prefix of __trace_ */
 		name = trace->prog + TRACE_PREFIX_LEN - 1;
 		if (buf[0]) {

src/trace.yaml

@@ -34,6 +34,7 @@ children:
         msg: packet is dropped by GRO
     - name: enqueue_to_backlog:0
       analyzer: ret
+      monitor: 1
       rules:
       - <<: *rule_ret_err
         msg: failed to enqeueu to CPU backlog
@@ -53,6 +54,7 @@ children:
         msg: packet is redirected by XDP program
     - name: xdp_do_generic_redirect:1
       analyzer: ret
+      monitor: 1
       rules:
       - <<: *rule_ret_err
         msg: XDP failed to redirect skb
@@ -70,6 +72,7 @@ children:
     children:
     - name: __dev_queue_xmit:0
       analyzer: ret
+      monitor: 1
       rules:
       - <<: *rule_ret_err
         msg: failed to queue packet to qdisc
@@ -80,6 +83,7 @@ children:
         msg: skb is successfully sent to the NIC driver
     - name: pfifo_enqueue
       analyzer: qdisc
+      monitor: 1
       target: pfifo_enqueue
       rules:
       - exp: ne 0
@@ -165,6 +169,7 @@ children:
         cond: '[ $(verlte "$(uname -r)" "5.16") -eq -1 ]' # valid when kernel < 5.16
         backup: *ipt_do_table
       analyzer: iptable
+      monitor: 1
       target: ipt_do_table
       rules:
       - exp: eq 0
@@ -192,6 +197,7 @@ children:
         msg: NAT happens (packet address will change)
         level: warn
     - name: nf_hook_slow
+      monitor: 1
       analyzer: nf
       rules:
       - exp: eq -1
@@ -214,6 +220,8 @@ children:
     - tcp_packet:1
     - name: tcp_in_window:4
       analyzer: ret
+      monitor: 1
+      arg_count: 7
       rules:
       - exp: eq 0
         level: warn
@@ -326,6 +334,7 @@ children:
         adv: check your target tcp port
     - name: inet6_lookup_listener:2
       analyzer: ret
+      monitor: 1
       rules:
       - exp: eq 0
         level: warn