Commit 5f2d9c44 authored by David Howells's avatar David Howells
Browse files

rxrpc: Randomise epoch and starting client conn ID values 



Create a random epoch value rather than a time-based one on startup and set
the top bit to indicate that this is the case.

Also create a random starting client connection ID value.  This will be
incremented from here as new client connections are created.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent af338a9e

include/rxrpc/packet.h

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ typedef __be32 rxrpc_serial_net_t; /* on-the-wire Rx message serial number */ 
 */

struct rxrpc_wire_header {

	__be32		epoch;		/* client boot timestamp */

#define RXRPC_RANDOM_EPOCH	0x80000000	/* Random if set, date-based if not */



	__be32		cid;		/* connection and channel ID */

#define RXRPC_MAXCALLS		4			/* max active calls per conn */

net/rxrpc/af_rxrpc.c

+8 −1
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/net.h>

#include <linux/slab.h>

#include <linux/skbuff.h>

#include <linux/random.h>

#include <linux/poll.h>

#include <linux/proc_fs.h>

#include <linux/key-type.h>
@@ -700,7 +701,13 @@ static int __init af_rxrpc_init(void) 


	BUILD_BUG_ON(sizeof(struct rxrpc_skb_priv) > FIELD_SIZEOF(struct sk_buff, cb));



	rxrpc_epoch = get_seconds();

	get_random_bytes(&rxrpc_epoch, sizeof(rxrpc_epoch));

	rxrpc_epoch |= RXRPC_RANDOM_EPOCH;

	get_random_bytes(&rxrpc_client_conn_ids.cur,

			 sizeof(rxrpc_client_conn_ids.cur));

	rxrpc_client_conn_ids.cur &= 0x3fffffff;

	if (rxrpc_client_conn_ids.cur == 0)

		rxrpc_client_conn_ids.cur = 1;



	ret = -ENOMEM;

	rxrpc_call_jar = kmem_cache_create(

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