Commit af094824 authored by David Howells's avatar David Howells
Browse files

rxrpc: Allow a delay to be injected into packet reception 



If CONFIG_AF_RXRPC_DEBUG_RX_DELAY=y, then a delay is injected between
packets and errors being received and them being made available to the
processing code, thereby allowing the RTT to be artificially increased.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
parent 223f5901

net/rxrpc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -36,6 +36,15 @@ config AF_RXRPC_INJECT_LOSS 
	  Say Y here to inject packet loss by discarding some received and some

	  transmitted packets.



config AF_RXRPC_INJECT_RX_DELAY

	bool "Inject delay into packet reception"

	depends on SYSCTL

	help

	  Say Y here to inject a delay into packet reception, allowing an

	  extended RTT time to be modelled.  The delay can be configured using

	  /proc/sys/net/rxrpc/rxrpc_inject_rx_delay, setting a number of

	  milliseconds up to 0.5s (note that the granularity is actually in

	  jiffies).



config AF_RXRPC_DEBUG

	bool "RxRPC dynamic debugging"

net/rxrpc/ar-internal.h

+6 −0
Original line number Diff line number Diff line
@@ -285,6 +285,9 @@ struct rxrpc_local { 
	struct completion	io_thread_ready; /* Indication that the I/O thread started */

	struct rxrpc_sock	*service;	/* Service(s) listening on this endpoint */

	struct rw_semaphore	defrag_sem;	/* control re-enablement of IP DF bit */

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

	struct sk_buff_head	rx_delay_queue;	/* Delay injection queue */

#endif

	struct sk_buff_head	rx_queue;	/* Received packets */

	struct list_head	conn_attend_q;	/* Conns requiring immediate attention */

	struct list_head	call_attend_q;	/* Calls requiring immediate attention */
@@ -1109,6 +1112,9 @@ extern unsigned long rxrpc_idle_ack_delay; 
extern unsigned int rxrpc_rx_window_size;

extern unsigned int rxrpc_rx_mtu;

extern unsigned int rxrpc_rx_jumbo_max;

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

extern unsigned long rxrpc_inject_rx_delay;

#endif



/*

 * net_ns.c

net/rxrpc/io_thread.c

+47 −1
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn, 
 */

int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)

{

	struct sk_buff_head *rx_queue;

	struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);



	if (unlikely(!local)) {
@@ -36,7 +37,16 @@ int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb) 


	skb->mark = RXRPC_SKB_MARK_PACKET;

	rxrpc_new_skb(skb, rxrpc_skb_new_encap_rcv);

	skb_queue_tail(&local->rx_queue, skb);

	rx_queue = &local->rx_queue;

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

	if (rxrpc_inject_rx_delay ||

	    !skb_queue_empty(&local->rx_delay_queue)) {

		skb->tstamp = ktime_add_ms(skb->tstamp, rxrpc_inject_rx_delay);

		rx_queue = &local->rx_delay_queue;

	}

#endif



	skb_queue_tail(rx_queue, skb);

	rxrpc_wake_up_io_thread(local);

	return 0;

}
@@ -407,6 +417,9 @@ int rxrpc_io_thread(void *data) 
	struct rxrpc_local *local = data;

	struct rxrpc_call *call;

	struct sk_buff *skb;

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

	ktime_t now;

#endif

	bool should_stop;



	complete(&local->io_thread_ready);
@@ -481,6 +494,17 @@ int rxrpc_io_thread(void *data) 
			continue;

		}



		/* Inject a delay into packets if requested. */

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

		now = ktime_get_real();

		while ((skb = skb_peek(&local->rx_delay_queue))) {

			if (ktime_before(now, skb->tstamp))

				break;

			skb = skb_dequeue(&local->rx_delay_queue);

			skb_queue_tail(&local->rx_queue, skb);

		}

#endif



		if (!skb_queue_empty(&local->rx_queue)) {

			spin_lock_irq(&local->rx_queue.lock);

			skb_queue_splice_tail_init(&local->rx_queue, &rx_queue);
@@ -502,6 +526,28 @@ int rxrpc_io_thread(void *data) 


		if (should_stop)

			break;



#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

		skb = skb_peek(&local->rx_delay_queue);

		if (skb) {

			unsigned long timeout;

			ktime_t tstamp = skb->tstamp;

			ktime_t now = ktime_get_real();

			s64 delay_ns = ktime_to_ns(ktime_sub(tstamp, now));



			if (delay_ns <= 0) {

				__set_current_state(TASK_RUNNING);

				continue;

			}



			timeout = nsecs_to_jiffies(delay_ns);

			timeout = max(timeout, 1UL);

			schedule_timeout(timeout);

			__set_current_state(TASK_RUNNING);

			continue;

		}

#endif



		schedule();

	}

net/rxrpc/local_object.c

+6 −0
Original line number Diff line number Diff line
@@ -110,6 +110,9 @@ static struct rxrpc_local *rxrpc_alloc_local(struct net *net, 
		INIT_HLIST_NODE(&local->link);

		init_rwsem(&local->defrag_sem);

		init_completion(&local->io_thread_ready);

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

		skb_queue_head_init(&local->rx_delay_queue);

#endif

		skb_queue_head_init(&local->rx_queue);

		INIT_LIST_HEAD(&local->conn_attend_q);

		INIT_LIST_HEAD(&local->call_attend_q);
@@ -434,6 +437,9 @@ void rxrpc_destroy_local(struct rxrpc_local *local) 
	/* At this point, there should be no more packets coming in to the

	 * local endpoint.

	 */

#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

	rxrpc_purge_queue(&local->rx_delay_queue);

#endif

	rxrpc_purge_queue(&local->rx_queue);

	rxrpc_purge_client_connections(local);

}

net/rxrpc/misc.c

+7 −0
Original line number Diff line number Diff line
@@ -53,3 +53,10 @@ unsigned int rxrpc_rx_mtu = 5692; 
 * sender that we're willing to handle.

 */

unsigned int rxrpc_rx_jumbo_max = 4;



#ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY

/*

 * The delay to inject into packet reception.

 */

unsigned long rxrpc_inject_rx_delay;

#endif