Create tcp_mss.py

kprobe_ko_ex/tcp_mss.py

@@ -0,0 +1,28 @@
+#!/usr/bin/python
+
+from bcc import BPF
+
+text="""
+#ifndef KBUILD_MODNAME
+#define KBUILD_MODNAME "bcc"
+#endif
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <net/ip.h>
+#include <uapi/linux/bpf.h>
+
+int  kretprobe__tcp_current_mss(struct pt_regs *ctx) {
+	struct sock *sk = (void *)PT_REGS_PARM1(ctx);
+	u32 mss = PT_REGS_RC(ctx);
+
+	if (!sk) {
+		return 0;
+	}
+
+	bpf_trace_printk("sk 0x%lx mss: %d\\n", sk, mss);
+
+	return 0;
+}
+"""
+
+BPF(text=text).trace_print()