Commit 1a70c05b authored by David Howells's avatar David Howells
Browse files

rxrpc: Break MTU determination from ICMP into its own function 



Break MTU determination from ICMP out into its own function to reduce the
complexity of the error report handler.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent abe89ef0

net/rxrpc/peer_event.c

+54 −39
Original line number Diff line number Diff line
@@ -71,6 +71,45 @@ static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local, 
	return rxrpc_lookup_peer_rcu(local, &srx);

}



/*

 * Handle an MTU/fragmentation problem.

 */

static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)

{

	u32 mtu = serr->ee.ee_info;



	_net("Rx ICMP Fragmentation Needed (%d)", mtu);



	/* wind down the local interface MTU */

	if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {

		peer->if_mtu = mtu;

		_net("I/F MTU %u", mtu);

	}



	if (mtu == 0) {

		/* they didn't give us a size, estimate one */

		mtu = peer->if_mtu;

		if (mtu > 1500) {

			mtu >>= 1;

			if (mtu < 1500)

				mtu = 1500;

		} else {

			mtu -= 100;

			if (mtu < peer->hdrsize)

				mtu = peer->hdrsize + 4;

		}

	}



	if (mtu < peer->mtu) {

		spin_lock_bh(&peer->lock);

		peer->mtu = mtu;

		peer->maxdata = peer->mtu - peer->hdrsize;

		spin_unlock_bh(&peer->lock);

		_net("Net MTU %u (maxdata %u)",

		     peer->mtu, peer->maxdata);

	}

}



/*

 * handle an error received on the local endpoint

 */
@@ -126,50 +165,26 @@ void rxrpc_error_report(struct sock *sk) 
		return;

	}



	if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&

	if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&

	     serr->ee.ee_type == ICMP_DEST_UNREACH &&

	    serr->ee.ee_code == ICMP_FRAG_NEEDED

	    ) {

		u32 mtu = serr->ee.ee_info;



		_net("Rx Received ICMP Fragmentation Needed (%d)", mtu);



		/* wind down the local interface MTU */

		if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {

			peer->if_mtu = mtu;

			_net("I/F MTU %u", mtu);

		}



		if (mtu == 0) {

			/* they didn't give us a size, estimate one */

			mtu = peer->if_mtu;

			if (mtu > 1500) {

				mtu >>= 1;

				if (mtu < 1500)

					mtu = 1500;

			} else {

				mtu -= 100;

				if (mtu < peer->hdrsize)

					mtu = peer->hdrsize + 4;

			}

		}



		if (mtu < peer->mtu) {

			spin_lock_bh(&peer->lock);

			peer->mtu = mtu;

			peer->maxdata = peer->mtu - peer->hdrsize;

			spin_unlock_bh(&peer->lock);

			_net("Net MTU %u (maxdata %u)",

			     peer->mtu, peer->maxdata);

		}

	     serr->ee.ee_code == ICMP_FRAG_NEEDED)) {

		rxrpc_adjust_mtu(peer, serr);

		rxrpc_free_skb(skb);

		skb = NULL;

		goto out;

	}



out:

	rcu_read_unlock();

	rxrpc_put_peer(peer);



	if (skb) {

		/* pass the transport ref to error_handler to release */

		skb_queue_tail(&trans->error_queue, skb);

		rxrpc_queue_work(&trans->error_handler);

	} else {

		rxrpc_put_transport(trans);

	}

	_leave("");

}