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Commit 97e5848d authored by Ian McDonald's avatar Ian McDonald Committed by David S. Miller
Browse files

[DCCP]: Introduce tx buffering 



This adds transmit buffering to DCCP.

I have tested with CCID2/3 and with loss and rate limiting.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a0109a7

include/linux/dccp.h

+2 −0
Original line number Diff line number Diff line
@@ -438,6 +438,7 @@ struct dccp_ackvec; 
 * @dccps_role - Role of this sock, one of %dccp_role

 * @dccps_ndp_count - number of Non Data Packets since last data packet

 * @dccps_hc_rx_ackvec - rx half connection ack vector

 * @dccps_xmit_timer - timer for when CCID is not ready to send

 */

struct dccp_sock {

	/* inet_connection_sock has to be the first member of dccp_sock */
@@ -470,6 +471,7 @@ struct dccp_sock { 
	enum dccp_role			dccps_role:2;

	__u8				dccps_hc_rx_insert_options:1;

	__u8				dccps_hc_tx_insert_options:1;

	struct timer_list		dccps_xmit_timer;

};

 

static inline struct dccp_sock *dccp_sk(const struct sock *sk)

net/dccp/dccp.h

+1 −1
Original line number Diff line number Diff line
@@ -130,7 +130,7 @@ extern void dccp_send_delayed_ack(struct sock *sk); 
extern void dccp_send_sync(struct sock *sk, const u64 seq,

			   const enum dccp_pkt_type pkt_type);



extern int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo);

extern void dccp_write_xmit(struct sock *sk, int block);

extern void dccp_write_space(struct sock *sk);



extern void dccp_init_xmit_timers(struct sock *sk);

net/dccp/output.c

+65 −25
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, 
	while (1) {

		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);



		if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))

		if (sk->sk_err)

			goto do_error;

		if (!*timeo)

			goto do_nonblock;
@@ -234,15 +234,45 @@ static int dccp_wait_for_ccid(struct sock *sk, struct sk_buff *skb, 
	goto out;

}



int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo)

static void dccp_write_xmit_timer(unsigned long data) {

	struct sock *sk = (struct sock *)data;

	struct dccp_sock *dp = dccp_sk(sk);



	bh_lock_sock(sk);

	if (sock_owned_by_user(sk))

		sk_reset_timer(sk, &dp->dccps_xmit_timer, jiffies+1);

	else

		dccp_write_xmit(sk, 0);

	bh_unlock_sock(sk);

	sock_put(sk);

}



void dccp_write_xmit(struct sock *sk, int block)

{

	const struct dccp_sock *dp = dccp_sk(sk);

	struct dccp_sock *dp = dccp_sk(sk);

	struct sk_buff *skb;

	long timeo = 30000; 	/* If a packet is taking longer than 2 secs

				   we have other issues */



	while ((skb = skb_peek(&sk->sk_write_queue))) {

		int err = ccid_hc_tx_send_packet(dp->dccps_hc_tx_ccid, sk, skb,

					 skb->len);



	if (err > 0)

		err = dccp_wait_for_ccid(sk, skb, timeo);

		if (err > 0) {

			if (!block) {

				sk_reset_timer(sk, &dp->dccps_xmit_timer,

						msecs_to_jiffies(err)+jiffies);

				break;

			} else

				err = dccp_wait_for_ccid(sk, skb, &timeo);

			if (err) {

				printk(KERN_CRIT "%s:err at dccp_wait_for_ccid"

						 " %d\n", __FUNCTION__, err);

				dump_stack();

			}

		}



		skb_dequeue(&sk->sk_write_queue);

		if (err == 0) {

			struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);

			const int len = skb->len;
@@ -261,10 +291,15 @@ int dccp_write_xmit(struct sock *sk, struct sk_buff *skb, long *timeo) 


			err = dccp_transmit_skb(sk, skb);

			ccid_hc_tx_packet_sent(dp->dccps_hc_tx_ccid, sk, 0, len);

			if (err) {

				printk(KERN_CRIT "%s:err from "

					         "ccid_hc_tx_packet_sent %d\n",

					         __FUNCTION__, err);

				dump_stack();

			}

		} else

		kfree_skb(skb);



	return err;

			kfree(skb);

	}

}



int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
@@ -426,6 +461,9 @@ static inline void dccp_connect_init(struct sock *sk) 
	dccp_set_seqno(&dp->dccps_awl, max48(dp->dccps_awl, dp->dccps_iss));



	icsk->icsk_retransmits = 0;

	init_timer(&dp->dccps_xmit_timer);

	dp->dccps_xmit_timer.data = (unsigned long)sk;

	dp->dccps_xmit_timer.function = dccp_write_xmit_timer;

}



int dccp_connect(struct sock *sk)
@@ -560,8 +598,10 @@ void dccp_send_close(struct sock *sk, const int active) 
					DCCP_PKT_CLOSE : DCCP_PKT_CLOSEREQ;



	if (active) {

		dccp_write_xmit(sk, 1);

		dccp_skb_entail(sk, skb);

		dccp_transmit_skb(sk, skb_clone(skb, prio));

		/* FIXME do we need a retransmit timer here? */

	} else

		dccp_transmit_skb(sk, skb);

}

net/dccp/proto.c

+5 −11
Original line number Diff line number Diff line
@@ -662,17 +662,8 @@ int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
	if (rc != 0)

		goto out_discard;



	rc = dccp_write_xmit(sk, skb, &timeo);

	/*

	 * XXX we don't use sk_write_queue, so just discard the packet.

	 *     Current plan however is to _use_ sk_write_queue with

	 *     an algorith similar to tcp_sendmsg, where the main difference

	 *     is that in DCCP we have to respect packet boundaries, so

	 *     no coalescing of skbs.

	 *

	 *     This bug was _quickly_ found & fixed by just looking at an OSTRA

	 *     generated callgraph 8) -acme

	 */

	skb_queue_tail(&sk->sk_write_queue, skb);

	dccp_write_xmit(sk,0);

out_release:

	release_sock(sk);

	return rc ? : len;
@@ -846,6 +837,7 @@ static int dccp_close_state(struct sock *sk) 


void dccp_close(struct sock *sk, long timeout)

{

	struct dccp_sock *dp = dccp_sk(sk);

	struct sk_buff *skb;

	int state;
@@ -862,6 +854,8 @@ void dccp_close(struct sock *sk, long timeout) 
		goto adjudge_to_death;

	}



	sk_stop_timer(sk, &dp->dccps_xmit_timer);



	/*

	 * We need to flush the recv. buffs.  We do this only on the

	 * descriptor close, not protocol-sourced closes, because the