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Diffstat (limited to 'net/ipv4/icmp.c')
-rw-r--r--net/ipv4/icmp.c64
1 files changed, 60 insertions, 4 deletions
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index ea7d4af..5882f58 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -231,12 +231,62 @@ static inline void icmp_xmit_unlock(struct sock *sk)
spin_unlock_bh(&sk->sk_lock.slock);
}
+int sysctl_icmp_msgs_per_sec __read_mostly = 1000;
+int sysctl_icmp_msgs_burst __read_mostly = 50;
+
+static struct {
+ spinlock_t lock;
+ u32 credit;
+ u32 stamp;
+} icmp_global = {
+ .lock = __SPIN_LOCK_UNLOCKED(icmp_global.lock),
+};
+
+/**
+ * icmp_global_allow - Are we allowed to send one more ICMP message ?
+ *
+ * Uses a token bucket to limit our ICMP messages to sysctl_icmp_msgs_per_sec.
+ * Returns false if we reached the limit and can not send another packet.
+ * Note: called with BH disabled
+ */
+bool icmp_global_allow(void)
+{
+ u32 credit, delta, incr = 0, now = (u32)jiffies;
+ bool rc = false;
+
+ /* Check if token bucket is empty and cannot be refilled
+ * without taking the spinlock.
+ */
+ if (!icmp_global.credit) {
+ delta = min_t(u32, now - icmp_global.stamp, HZ);
+ if (delta < HZ / 50)
+ return false;
+ }
+
+ spin_lock(&icmp_global.lock);
+ delta = min_t(u32, now - icmp_global.stamp, HZ);
+ if (delta >= HZ / 50) {
+ incr = sysctl_icmp_msgs_per_sec * delta / HZ ;
+ if (incr)
+ icmp_global.stamp = now;
+ }
+ credit = min_t(u32, icmp_global.credit + incr, sysctl_icmp_msgs_burst);
+ if (credit) {
+ credit--;
+ rc = true;
+ }
+ icmp_global.credit = credit;
+ spin_unlock(&icmp_global.lock);
+ return rc;
+}
+EXPORT_SYMBOL(icmp_global_allow);
+
/*
* Send an ICMP frame.
*/
-static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
- struct flowi4 *fl4, int type, int code)
+static bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
+ struct flowi4 *fl4, int type, int code)
{
struct dst_entry *dst = &rt->dst;
bool rc = true;
@@ -253,8 +303,14 @@ static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
goto out;
/* Limit if icmp type is enabled in ratemask. */
- if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
- struct inet_peer *peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1);
+ if (!((1 << type) & net->ipv4.sysctl_icmp_ratemask))
+ goto out;
+
+ rc = false;
+ if (icmp_global_allow()) {
+ struct inet_peer *peer;
+
+ peer = inet_getpeer_v4(net->ipv4.peers, fl4->daddr, 1);
rc = inet_peer_xrlim_allow(peer,
net->ipv4.sysctl_icmp_ratelimit);
if (peer)
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