Initial commit for TCP ROCCET source code.

roccet_kprobe.c

@@ -0,0 +1,66 @@
+#include "linux/kprobes.h"
+
+#include <linux/inet_diag.h>
+#include <net/tcp.h>
+
+/* Include the struct of the ROCCET congestion control algorithm. */
+#include "tcp_roccet.h"
+
+// Handler for the pre-call probe
+static int handler_pre(struct kprobe *p, struct pt_regs *regs)
+{
+	/* System V ABI for x86_64 Linux:
+	 * arg0: di,
+	 * arg1: si,
+	 * arg2: dx,
+	 * ...
+	 */
+
+	/* Get the first argument of the probed function */
+	struct sock *sk = (struct sock *)regs->di;
+	struct roccettcp *ca = inet_csk_ca(sk);
+
+	u32 ack = (u32)regs->si;
+	u32 acked = (u32)regs->dx;
+
+	/* Use `trace_printk` to print debug information to the
+	 * `/sys/kernel/tracing/trace buffer`.
+	 * This buffer can be read using the debug trace interface of the kernel.
+	 */
+	trace_printk(
+		"roccettcp_cong_avoid: sk=%p ca=%p cnt=%u last_max_cwnd=%u, "
+		"last_congestion_event=%u\n",
+		sk, ca, ca->cnt, ca->last_max_cwnd,
+		ca->roccet_last_event_time_us);
+	trace_printk("ack: %u acked: %u\n", ack, acked);
+
+	return 0;
+}
+
+static struct kprobe kp = {
+
+	/* Define which function to probe. */
+	.symbol_name = "roccettcp_cong_avoid",
+	.pre_handler = handler_pre, /* Runs before the probed function. */
+	.post_handler = NULL, /* Runs after the probed function. */
+
+};
+
+static int __init kprobe_init(void)
+{
+	return register_kprobe(&kp);
+}
+static void __exit kprobe_exit(void)
+{
+	unregister_kprobe(&kp);
+}
+
+module_init(kprobe_init);
+module_exit(kprobe_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Makes it possible to probe the ROCCET Congestion "
+		   "Control Algrithm with kprobes. This enabled Debugging via a "
+		   "loadable kernel module.");
+MODULE_AUTHOR("Tim Füchsel");
+MODULE_VERSION("0.1");