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authorDavid S. Miller <davem@davemloft.net>2011-02-04 15:55:25 -0800
committerDavid S. Miller <davem@davemloft.net>2011-02-04 15:59:53 -0800
commit92d8682926342d2b6aa5b2ecc02221e00e1573a0 (patch)
tree7f70b9cc2975716ab60ddd632b9fecf0a51b828d /net/ipv4/inetpeer.c
parent0131ba451e20239c5dc701027c1a2edef95e1a6e (diff)
downloadlwn-92d8682926342d2b6aa5b2ecc02221e00e1573a0.tar.gz
lwn-92d8682926342d2b6aa5b2ecc02221e00e1573a0.zip
inetpeer: Move ICMP rate limiting state into inet_peer entries.
Like metrics, the ICMP rate limiting bits are cached state about a destination. So move it into the inet_peer entries. If an inet_peer cannot be bound (the reason is memory allocation failure or similar), the policy is to allow. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/inetpeer.c')
-rw-r--r--net/ipv4/inetpeer.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index b6513b13d729..709fbb4132d7 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -513,6 +513,8 @@ struct inet_peer *inet_getpeer(struct inetpeer_addr *daddr, int create)
atomic_set(&p->ip_id_count, secure_ip_id(daddr->a4));
p->tcp_ts_stamp = 0;
p->metrics[RTAX_LOCK-1] = INETPEER_METRICS_NEW;
+ p->rate_tokens = 0;
+ p->rate_last = 0;
INIT_LIST_HEAD(&p->unused);
@@ -580,3 +582,44 @@ void inet_putpeer(struct inet_peer *p)
local_bh_enable();
}
EXPORT_SYMBOL_GPL(inet_putpeer);
+
+/*
+ * Check transmit rate limitation for given message.
+ * The rate information is held in the inet_peer entries now.
+ * This function is generic and could be used for other purposes
+ * too. It uses a Token bucket filter as suggested by Alexey Kuznetsov.
+ *
+ * Note that the same inet_peer fields are modified by functions in
+ * route.c too, but these work for packet destinations while xrlim_allow
+ * works for icmp destinations. This means the rate limiting information
+ * for one "ip object" is shared - and these ICMPs are twice limited:
+ * by source and by destination.
+ *
+ * RFC 1812: 4.3.2.8 SHOULD be able to limit error message rate
+ * SHOULD allow setting of rate limits
+ *
+ * Shared between ICMPv4 and ICMPv6.
+ */
+#define XRLIM_BURST_FACTOR 6
+bool inet_peer_xrlim_allow(struct inet_peer *peer, int timeout)
+{
+ unsigned long now, token;
+ bool rc = false;
+
+ if (!peer)
+ return true;
+
+ token = peer->rate_tokens;
+ now = jiffies;
+ token += now - peer->rate_last;
+ peer->rate_last = now;
+ if (token > XRLIM_BURST_FACTOR * timeout)
+ token = XRLIM_BURST_FACTOR * timeout;
+ if (token >= timeout) {
+ token -= timeout;
+ rc = true;
+ }
+ peer->rate_tokens = token;
+ return rc;
+}
+EXPORT_SYMBOL(inet_peer_xrlim_allow);