Update repository to the state of the latest kernel patch.

Make formatting linux conform

See merge request lukas.prause/tcp-roccet-kernel-module!1

README.md

@@ -1,35 +1,55 @@
 # TCP ROCCET :rocket: (RTT Oriented CUBIC Congestion control ExTension)
 
-TCP ROCCET is a new TCP congestion control
+TCP ROCCET is a new TCP congestion control algorithm that reduces latency by detecting queuing.
-algorithm suited for current cellular 5G NR beyond networks.
+Additionally, it is specially suited for 4G/5G cellular networks.
-It extends the kernel default congestion control CUBIC
-and improves its performance, and additionally solves
-unwanted side effects of CUBIC’s implementation.
-ROCCET uses its own Slow Start, called LAUNCH, where loss
-is not considered as a congestion event.
-The congestion avoidance phase, called ORBITER, uses 
-CUBIC's window growth function and adds, based on RTT
-and ACK rate, congestion events.
 
-NOTE: A paper for TCP ROCCET is currently under review.
+A peer-reviewed [paper on TCP ROCCET](https://opendl.ifip-tc6.org/db/conf/wons/wons2026/1571217211.pdf) was presented at the WONS 2026 conference.
-Paper draft:
-            https://arxiv.org/abs/2510.25281
 
-The oldest Linux kernel version we tested with ROCCET is 6.1.
+A new performance report for the latest version of TCP ROCCET can be found under "doc/measurements/2026-07-21_performance-report.pdf".
 
-## Setup
+### Versions
 
+- latest on master branch (requires kernel version 7.1 or higher)
+    - Improved min RTT probing
+    - Packet pacing
+    - Code refactor
+    - Monitoring send and receive rate
+
+- release-2026-06-12-v1
+    - Adds minimum RTT probing
+    
+## Install with apt (requires kernel version 6.10 or higher)
+Add tcp-roccet-dkms to your source lists and install:
+
+```
+echo "deb [trusted=yes] https://apt.fury.io/timfuchs/ /" | sudo tee /etc/apt/sources.list.d/tcp-roccet.list
+sudo apt update
+sudo apt install tcp-roccet-dkms
+```
+
+### Loading and using the congestion control
+Note: This change is not persistent, the module will not be loaded at boot.
+
+```
+sudo modprobe tcp_roccet
+sudo sysctl net.ipv4.tcp_congestion_control=roccet
+```
+
+## Build from source
+
+### Setup
+Kernel headers are required:
 * Debian: `sudo apt install linux-headers-generic`
 * Fedora: `sudo dnf install kernel-devel`
 (`sudo reboot`)
 
-## Build 
+### Build 
 `make`
 
 
 ## Loading & Unloading the Module  
 **1.** Insert into Kernel: `sudo insmod tcp_roccet.ko`
-In case you get the "Invalid module Format" error, it can help reinstalling the kernel-headers.
+In case you get the "Invalid module Format" error, it can help to reinstall the kernel-headers.
 
 **2.** Use the Algorithm:
 * Either via globally loading it: `sudo sysctl net.ipv4.tcp_congestion_control=roccet`
@@ -39,12 +59,12 @@ In case you get the "Invalid module Format" error, it can help reinstalling the
 
 
 ## Debugging (Using kprobe)
-In order to debug the `tcp_roccet` congestion control algorithm, there exists a Kprobe module (`roccet_kprobe.c`). Using this it is possible to inspect events generated by the algorithm. 
+In order to debug the `tcp_roccet` congestion control algorithm, there exists a Kprobe module (`roccet_kprobe.c`). Using this, it is possible to inspect events generated by the algorithm. 
 
-In order to use the Kprobe module the following steps are necessary: 
+In order to use the Kprobe module, the following steps are necessary: 
 
 **1. Specify the event to inspect**
-For this head into the `tcp_roccet.c` source code and find the function the Kprobe should attach to. 
+For this, head into the `tcp_roccet.c` source code and find the function the Kprobe should attach to. 
 
 For Example: 
 ```
@@ -69,7 +89,7 @@ Required files for this are:
 * `tcp_roccet.c` (Optional; Need to remove corresponding entry in Makefile if missing)
 
 **3. Load Kprobe module**
-To then load the Module use 
+To then load the module use 
 `sudo insmod roccet_kprobe.ko` 
 If you are seeing the error "Unknown symbol in module" you need to first load the roccet algorithm.  
 
@@ -78,21 +98,7 @@ To see the trace output use
 `sudo cat /sys/kernel/tracing/trace_pipe`
 
 **5. Unload Kprobe module**
-To remove the module again use 
+To remove the module again, use 
 `sudo rmmod roccet_kprobe` 
 
 _See more info at_ https://docs.kernel.org/trace/kprobes.html and https://www.kernel.org/doc/Documentation/trace/kprobetrace.rst
-
-## Further Info
-* On TCP-CC Ops: 
-    * https://www.yonch.com/tech/linux-tcp-congestion-control-internals
-    * https://docs.ebpf.io/linux/program-type/BPF_PROG_TYPE_STRUCT_OPS/tcp_congestion_ops/
-
-# Setup Development Environment 
-For specific Kernel:  
-1. Download linux source (the version you want to develop for)
-2. Create Config via `make defconfig`
-3. Compile kernel via `make`
-4. Generate clangd Config via `python scripts/clang-tools/gen_compile_commands.py`
-5. Copy `compile_commands.json` to development directory  
-

tcp_roccet.h

@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * TCP ROCCET congestion control interface
  */
@@ -6,25 +7,19 @@
 
 #include <linux/math64.h>
 
-struct AckRate {
+/* State in which roccet currently operates */
-	u16 last_rate;	/* Last ACK-rate */
+enum roccet_state {
-	u32 last_rate_time; /* Timestamp of the last ACK-rate */
+	LAUNCH,
-	u16 curr_rate; 	/* Current ACK-rate */
+	ORBITER,
-	u16 cnt; 	/* Used for counting acks */
+	RTT_PROBE_ENTER,
+	RTT_PROBE,
+	RTT_PROBE_REFILL,
+	DRAIN
 };
 
-struct BandwidthLimitDetect {
+/* TCP ROCCET struct based on the original BICTCP struct with
-	u32 sum_cwnd; 	/* sum of cwnd during time interval */
+ * additions specific to the ROCCET-Algorithm.
-	u32 sum_acked; 	/* sum of received acks during time interval */
+ */
-	u32 next_check; /* end/upper bound of time interval */
-};
-
-struct TimedRTT {
-	u32 time; /* Time of recoding */
-	u32 rtt;  /* Measured RTT */
-};
-
-/* Based on the BICTCP struct with additions specific for the ROCCET-Algorithm */
 struct roccettcp {
 	u32 cnt;	/* increase cwnd by 1 after ACKs */
 	u32 last_max_cwnd;	/* last maximum snd_cwnd */
@@ -32,21 +27,51 @@ struct roccettcp {
 	u32 last_time;	/* time when updated last_cwnd */
 	u32 bic_origin_point;	/* origin point of bic function */
 	u32 bic_K;	/* time to origin point from the
-				beginning of the current epoch */
+			 * beginning of the current epoch
+			 */
 	u32 delay_min;	/* min delay (usec) */
 	u32 epoch_start;	/* beginning of an epoch */
 	u32 ack_cnt;	/* number of acks */
 	u32 tcp_cwnd;	/* estimated tcp cwnd */
-	u32 curr_rtt; 		/* the minimum rtt of current round */
+	u32 curr_rtt;	/* last sample rtt of current round */
 
-	u32 roccet_last_event_time_us; 	/* The last time ROCCETv2 was triggered */
+	u32 roccet_last_event_time_us;	/* The last time ROCCET was triggered */
 	u32 curr_min_rtt;	/* The current observed minRTT */
-	struct TimedRTT curr_min_rtt_timed; /* The current observed minRTT with 
+	u32 next_min_rtt_probe;	/* Next time to probe the minRTT */
-						the timestamp when it was observed */
+	u32 probe_min_rtt_until;	/* End of minRTT probing period.
-	u32 curr_srRTT; 		/* The srRTT calculated based on the latest ACK */
+					 * Set while in RTT_PROBE states
-	struct AckRate ack_rate; 	/* The last and the current ACK rate */
+					 */
-	struct BandwidthLimitDetect bw_limit;
+	u32 refill_until;	/* End of pipe refill after minRTT probe.
-	u32 last_rtt; 			/* Used for jitter calculation */
+				 * Set while in RTT_PROBE states
+				 */
+	u32 cwnd_before_min_rtt_probe;	/* cwnd before min RTT probing. */
+	u32 curr_srrtt;	/* srRTT calculated based on the latest ACK */
+	u32 next_srrtt_check_ts;	/* Next check for srRTT */
+	u32 last_rtt;	/* sample rtt of previous round.
+			 * Used for jitter calculation
+			 */
+
+	u32 interval_snd_seq_start;
+	u32 interval_una_seq_start;
+
+	u32 ack_rate_last_rate_time;	/* Timestamp of the last ACK-rate */
+	u16 ack_rate_last_rate;	/* Last ACK-rate */
+	u16 ack_rate_curr_rate;	/* Current ACK-rate */
+	u16 ack_rate_cnt;	/* Used for counting acks */
+
+	enum roccet_state state : 3; /* Current operating state of roccet */
+	bool was_idle : 1;	/* Tracks whether the connection was idle
+				 * (had no in-flight packets)
+				 */
+	bool initial_limit_reached: 1;	/* Set to true after the connection
+					 * initially gets cwnd-limited
+					 */
+	bool is_in_initial_launch: 1;	/* true if the connection is in
+					 * the initial launch phase.
+					 */
+	u32 ack_carry_over;	/* Used to carry over leftover acks from
+				 * LAUNCH to ORBITER
+				 */
 };
 
 #endif /* __TCP_ROCCET_H */