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Commit 06393009 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

[SCTP]: port randomization 



Add port randomization rather than a simple fixed rover
for use with SCTP.  This makes it act similar to TCP, UDP, DCCP
when allocating ports.

No longer need port_alloc_lock as well (suggestion by Brian Haley).

Signed-off-by: default avatarStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3c0cfc13

include/net/sctp/structs.h

+0 −2
Original line number Original line Diff line number Diff line
@@ -197,8 +197,6 @@ extern struct sctp_globals { 




	/* This is the sctp port control hash.	*/

	/* This is the sctp port control hash.	*/

	int port_hashsize;

	int port_hashsize;

	int port_rover;

	spinlock_t port_alloc_lock;  /* Protects port_rover. */

	struct sctp_bind_hashbucket *port_hashtable;

	struct sctp_bind_hashbucket *port_hashtable;





	/* This is the global local address list.

	/* This is the global local address list.

net/sctp/protocol.c

+0 −3
Original line number Original line Diff line number Diff line
@@ -1172,9 +1172,6 @@ SCTP_STATIC __init int sctp_init(void) 
		sctp_port_hashtable[i].chain = NULL;

		sctp_port_hashtable[i].chain = NULL;

	}

	}





	spin_lock_init(&sctp_port_alloc_lock);

	sctp_port_rover = sysctl_local_port_range[0] - 1;



	printk(KERN_INFO "SCTP: Hash tables configured "

	printk(KERN_INFO "SCTP: Hash tables configured "

			 "(established %d bind %d)\n",

			 "(established %d bind %d)\n",

		sctp_assoc_hashsize, sctp_port_hashsize);

		sctp_assoc_hashsize, sctp_port_hashsize);

net/sctp/socket.c

+5 −16
Original line number Original line Diff line number Diff line
@@ -5314,22 +5314,13 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr) 
	sctp_local_bh_disable();

	sctp_local_bh_disable();





	if (snum == 0) {

	if (snum == 0) {

		/* Search for an available port.

		/* Search for an available port. */

		 *

		unsigned int low = sysctl_local_port_range[0];

		 * 'sctp_port_rover' was the last port assigned, so

		unsigned int high = sysctl_local_port_range[1];

		 * we start to search from 'sctp_port_rover +

		unsigned int remaining = (high - low) + 1;

		 * 1'. What we do is first check if port 'rover' is

		unsigned int rover = net_random() % remaining + low;

		 * already in the hash table; if not, we use that; if

		 * it is, we try next.

		 */

		int low = sysctl_local_port_range[0];

		int high = sysctl_local_port_range[1];

		int remaining = (high - low) + 1;

		int rover;

		int index;

		int index;





		sctp_spin_lock(&sctp_port_alloc_lock);

		rover = sctp_port_rover;

		do {

		do {

			rover++;

			rover++;

			if ((rover < low) || (rover > high))

			if ((rover < low) || (rover > high))
@@ -5344,8 +5335,6 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr) 
		next:

		next:

			sctp_spin_unlock(&head->lock);

			sctp_spin_unlock(&head->lock);

		} while (--remaining > 0);

		} while (--remaining > 0);

		sctp_port_rover = rover;

		sctp_spin_unlock(&sctp_port_alloc_lock);





		/* Exhausted local port range during search? */

		/* Exhausted local port range during search? */

		ret = 1;

		ret = 1;