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>

3 files changed, 89 insertions, 59 deletions

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 4aa1b7f01ea0..ad2bcf1b69ae 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -233,48 +233,11 @@ static inline void icmp_xmit_unlock(struct sock *sk)
  *      Send an ICMP frame.
  */
 
-/*
- *      Check transmit rate limitation for given message.
- *      The rate information is held in the destination cache 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 dst_entry 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
-int xrlim_allow(struct dst_entry *dst, int timeout)
-{
-        unsigned long now, token = dst->rate_tokens;
-        int rc = 0;
-
-        now = jiffies;
-        token += now - dst->rate_last;
-        dst->rate_last = now;
-        if (token > XRLIM_BURST_FACTOR * timeout)
-                token = XRLIM_BURST_FACTOR * timeout;
-        if (token >= timeout) {
-                token -= timeout;
-                rc = 1;
-        }
-        dst->rate_tokens = token;
-        return rc;
-}
-EXPORT_SYMBOL(xrlim_allow);
-
-static inline int icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
+static inline bool icmpv4_xrlim_allow(struct net *net, struct rtable *rt,
                 int type, int code)
 {
         struct dst_entry *dst = &rt->dst;
-        int rc = 1;
+        bool rc = true;
 
         if (type > NR_ICMP_TYPES)
                 goto out;
@@ -288,8 +251,12 @@ static inline int 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)
-                rc = xrlim_allow(dst, net->ipv4.sysctl_icmp_ratelimit);
+        if ((1 << type) & net->ipv4.sysctl_icmp_ratemask) {
+                if (!rt->peer)
+                        rt_bind_peer(rt, 1);
+                rc = inet_peer_xrlim_allow(rt->peer,
+                                           net->ipv4.sysctl_icmp_ratelimit);
+        }
 out:
         return rc;
 }
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);
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 0ba6a382b2b4..2e225dafc4f8 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1563,6 +1563,7 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 {
         struct rtable *rt = skb_rtable(skb);
         struct in_device *in_dev;
+        struct inet_peer *peer;
         int log_martians;
 
         rcu_read_lock();
@@ -1574,33 +1575,41 @@ void ip_rt_send_redirect(struct sk_buff *skb)
         log_martians = IN_DEV_LOG_MARTIANS(in_dev);
         rcu_read_unlock();
 
+        if (!rt->peer)
+                rt_bind_peer(rt, 1);
+        peer = rt->peer;
+        if (!peer) {
+                icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
+                return;
+        }
+
         /* No redirected packets during ip_rt_redirect_silence;
          * reset the algorithm.
          */
-        if (time_after(jiffies, rt->dst.rate_last + ip_rt_redirect_silence))
-                rt->dst.rate_tokens = 0;
+        if (time_after(jiffies, peer->rate_last + ip_rt_redirect_silence))
+                peer->rate_tokens = 0;
 
         /* Too many ignored redirects; do not send anything
          * set dst.rate_last to the last seen redirected packet.
          */
-        if (rt->dst.rate_tokens >= ip_rt_redirect_number) {
-                rt->dst.rate_last = jiffies;
+        if (peer->rate_tokens >= ip_rt_redirect_number) {
+                peer->rate_last = jiffies;
                 return;
         }
 
         /* Check for load limit; set rate_last to the latest sent
          * redirect.
          */
-        if (rt->dst.rate_tokens == 0 ||
+        if (peer->rate_tokens == 0 ||
             time_after(jiffies,
-                       (rt->dst.rate_last +
-                        (ip_rt_redirect_load << rt->dst.rate_tokens)))) {
+                       (peer->rate_last +
+                        (ip_rt_redirect_load << peer->rate_tokens)))) {
                 icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, rt->rt_gateway);
-                rt->dst.rate_last = jiffies;
-                ++rt->dst.rate_tokens;
+                peer->rate_last = jiffies;
+                ++peer->rate_tokens;
 #ifdef CONFIG_IP_ROUTE_VERBOSE
                 if (log_martians &&
-                    rt->dst.rate_tokens == ip_rt_redirect_number &&
+                    peer->rate_tokens == ip_rt_redirect_number &&
                     net_ratelimit())
                         printk(KERN_WARNING "host %pI4/if%d ignores redirects for %pI4 to %pI4.\n",
                                 &rt->rt_src, rt->rt_iif,
@@ -1612,7 +1621,9 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 static int ip_error(struct sk_buff *skb)
 {
         struct rtable *rt = skb_rtable(skb);
+        struct inet_peer *peer;
         unsigned long now;
+        bool send;
         int code;
 
         switch (rt->dst.error) {
@@ -1632,15 +1643,24 @@ static int ip_error(struct sk_buff *skb)
                         break;
         }
 
-        now = jiffies;
-        rt->dst.rate_tokens += now - rt->dst.rate_last;
-        if (rt->dst.rate_tokens > ip_rt_error_burst)
-                rt->dst.rate_tokens = ip_rt_error_burst;
-        rt->dst.rate_last = now;
-        if (rt->dst.rate_tokens >= ip_rt_error_cost) {
-                rt->dst.rate_tokens -= ip_rt_error_cost;
-                icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
+        if (!rt->peer)
+                rt_bind_peer(rt, 1);
+        peer = rt->peer;
+
+        send = true;
+        if (peer) {
+                now = jiffies;
+                peer->rate_tokens += now - peer->rate_last;
+                if (peer->rate_tokens > ip_rt_error_burst)
+                        peer->rate_tokens = ip_rt_error_burst;
+                peer->rate_last = now;
+                if (peer->rate_tokens >= ip_rt_error_cost)
+                        peer->rate_tokens -= ip_rt_error_cost;
+                else
+                        send = false;
         }
+        if (send)
+                icmp_send(skb, ICMP_DEST_UNREACH, code, 0);
 
 out:    kfree_skb(skb);
         return 0;