[IPSEC]: Sync series - core changes

This patch provides the core functionality needed for sync events
for ipsec. Derived work of Krisztian KOVACS <hidden@balabit.hu>

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 78 insertions, 2 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index c656cbaf35e8..8eaee499cad5 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -20,6 +20,8 @@
 #include <linux/module.h>
 #include <asm/uaccess.h>
 
+u32 sysctl_xfrm_aevent_etime = XFRM_AE_ETIME;
+u32 sysctl_xfrm_aevent_rseqth = XFRM_AE_SEQT_SIZE;
 /* Each xfrm_state may be linked to two tables:
 
    1. Hash table by (spi,daddr,ah/esp) to find SA by SPI. (input,ctl)
@@ -62,6 +64,8 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x)
 {
         if (del_timer(&x->timer))
                 BUG();
+        if (del_timer(&x->rtimer))
+                BUG();
         kfree(x->aalg);
         kfree(x->ealg);
         kfree(x->calg);
@@ -190,11 +194,16 @@ struct xfrm_state *xfrm_state_alloc(void)
                 init_timer(&x->timer);
                 x->timer.function = xfrm_timer_handler;
                 x->timer.data     = (unsigned long)x;
+                init_timer(&x->rtimer);
+                x->rtimer.function = xfrm_replay_timer_handler;
+                x->rtimer.data     = (unsigned long)x;
                 x->curlft.add_time = (unsigned long)xtime.tv_sec;
                 x->lft.soft_byte_limit = XFRM_INF;
                 x->lft.soft_packet_limit = XFRM_INF;
                 x->lft.hard_byte_limit = XFRM_INF;
                 x->lft.hard_packet_limit = XFRM_INF;
+                x->replay_maxage = 0;
+                x->replay_maxdiff = 0;
                 spin_lock_init(&x->lock);
         }
         return x;
@@ -228,6 +237,8 @@ static int __xfrm_state_delete(struct xfrm_state *x)
                 spin_unlock(&xfrm_state_lock);
                 if (del_timer(&x->timer))
                         __xfrm_state_put(x);
+                if (del_timer(&x->rtimer))
+                        __xfrm_state_put(x);
 
                 /* The number two in this test is the reference
                  * mentioned in the comment below plus the reference
@@ -426,6 +437,10 @@ static void __xfrm_state_insert(struct xfrm_state *x)
         if (!mod_timer(&x->timer, jiffies + HZ))
                 xfrm_state_hold(x);
 
+        if (x->replay_maxage &&
+            !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
+                xfrm_state_hold(x);
+
         wake_up(&km_waitq);
 }
 
@@ -762,6 +777,62 @@ out:
 }
 EXPORT_SYMBOL(xfrm_state_walk);
 
+
+void xfrm_replay_notify(struct xfrm_state *x, int event)
+{
+        struct km_event c;
+        /* we send notify messages in case
+         *  1. we updated on of the sequence numbers, and the seqno difference
+         *     is at least x->replay_maxdiff, in this case we also update the
+         *     timeout of our timer function
+         *  2. if x->replay_maxage has elapsed since last update,
+         *     and there were changes
+         *
+         *  The state structure must be locked!
+         */
+
+        switch (event) {
+        case XFRM_REPLAY_UPDATE:
+                if (x->replay_maxdiff &&
+                    (x->replay.seq - x->preplay.seq < x->replay_maxdiff) &&
+                    (x->replay.oseq - x->preplay.oseq < x->replay_maxdiff))
+                        return;
+
+                break;
+
+        case XFRM_REPLAY_TIMEOUT:
+                if ((x->replay.seq == x->preplay.seq) &&
+                    (x->replay.bitmap == x->preplay.bitmap) &&
+                    (x->replay.oseq == x->preplay.oseq))
+                        return;
+
+                break;
+        }
+
+        memcpy(&x->preplay, &x->replay, sizeof(struct xfrm_replay_state));
+        c.event = XFRM_MSG_NEWAE;
+        c.data.aevent = event;
+        km_state_notify(x, &c);
+
+resched:
+        if (x->replay_maxage &&
+            !mod_timer(&x->rtimer, jiffies + x->replay_maxage))
+                xfrm_state_hold(x);
+
+}
+
+static void xfrm_replay_timer_handler(unsigned long data)
+{
+        struct xfrm_state *x = (struct xfrm_state*)data;
+
+        spin_lock(&x->lock);
+
+        if (xfrm_aevent_is_on() && x->km.state == XFRM_STATE_VALID)
+                xfrm_replay_notify(x, XFRM_REPLAY_TIMEOUT);
+
+        spin_unlock(&x->lock);
+}
+
 int xfrm_replay_check(struct xfrm_state *x, u32 seq)
 {
         u32 diff;
@@ -805,6 +876,9 @@ void xfrm_replay_advance(struct xfrm_state *x, u32 seq)
                 diff = x->replay.seq - seq;
                 x->replay.bitmap |= (1U << diff);
         }
+
+        if (xfrm_aevent_is_on())
+                xfrm_replay_notify(x, XFRM_REPLAY_UPDATE);
 }
 EXPORT_SYMBOL(xfrm_replay_advance);
 
@@ -835,7 +909,7 @@ void km_state_notify(struct xfrm_state *x, struct km_event *c)
 EXPORT_SYMBOL(km_policy_notify);
 EXPORT_SYMBOL(km_state_notify);
 
-static void km_state_expired(struct xfrm_state *x, int hard)
+void km_state_expired(struct xfrm_state *x, int hard)
 {
         struct km_event c;
 
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 7de17559249a..6f643e58e044 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -28,7 +28,7 @@
 #include <net/netlink.h>
 #include <asm/uaccess.h>
 
-static struct sock *xfrm_nl;
+struct sock *xfrm_nl;
 
 static int verify_one_alg(struct rtattr **xfrma, enum xfrm_attr_type_t type)
 {
@@ -1618,3 +1618,5 @@ module_init(xfrm_user_init);
 module_exit(xfrm_user_exit);
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_XFRM);
+EXPORT_SYMBOL(xfrm_nl);
+