Add percpu buffer flag

Signed-off-by: Adv <[email protected]>

Author: AdvH039

bpf/kprobe_pwru.c

@@ -209,7 +209,7 @@ struct {
 struct {
 	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
 	__type(key, u32);
-	__type(value, u8[PERCPU_BIG_BUFF_SIZE]);
+	__uint(value_size, PERCPU_BIG_BUFF_SIZE);
 	__uint(max_entries, 1);
 } percpu_big_buff SEC(".maps");
 

internal/pwru/types.go

@@ -65,6 +65,8 @@ type Flags struct {
 	ReadyFile string
 
 	Backend string
+
+	SetPerCPUBuf uint32
 }
 
 func (f *Flags) SetFlags() {
@@ -110,6 +112,7 @@ func (f *Flags) SetFlags() {
 	flag.StringVar(&f.Backend, "backend", "",
 		fmt.Sprintf("Tracing backend('%s', '%s'). Will auto-detect if not specified.", BackendKprobe, BackendKprobeMulti))
 
+	flag.Uint32Var(&f.SetPerCPUBuf, "set-percpu-buf", 4096, "set the size of buffers to print skb data (used by --output-skb and --output-skb-shared-info)")
 	flag.Usage = func() {
 		fmt.Fprintf(os.Stderr, "Usage: %s [options] [pcap-filter]\n", os.Args[0])
 		fmt.Fprintf(os.Stderr, "    Available pcap-filter: see \"man 7 pcap-filter\"\n")

main.go

@@ -195,6 +195,8 @@ func main() {
 		log.Fatalf("Failed to rewrite config: %v", err)
 	}
 
+	bpfSpec.Maps["percpu_big_buff"].ValueSize = flags.SetPerCPUBuf
+	
 	haveFexit := pwru.HaveBPFLinkTracing()
 	if (flags.FilterTraceTc || flags.FilterTraceXdp) && !haveFexit {
 		log.Fatalf("Current kernel does not support fentry/fexit to run with --filter-trace-tc/--filter-trace-xdp")