2 files changed, 32 insertions, 30 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 9fe1d535cd6c..5b29835b81d8 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1216,36 +1216,8 @@ static inline bool tcp_paws_reject(const struct tcp_options_received *rx_opt,
         return true;
 }
 
-/* Return true if we're currently rate-limiting out-of-window ACKs and
- * thus shouldn't send a dupack right now. We rate-limit dupacks in
- * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
- * attacks that send repeated SYNs or ACKs for the same connection. To
- * do this, we do not send a duplicate SYNACK or ACK if the remote
- * endpoint is sending out-of-window SYNs or pure ACKs at a high rate.
- */
-static inline bool tcp_oow_rate_limited(struct net *net,
-                                        const struct sk_buff *skb,
-                                        int mib_idx, u32 *last_oow_ack_time)
-{
-        /* Data packets without SYNs are not likely part of an ACK loop. */
-        if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
-            !tcp_hdr(skb)->syn)
-                goto not_rate_limited;
-
-        if (*last_oow_ack_time) {
-                s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
-
-                if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
-                        NET_INC_STATS_BH(net, mib_idx);
-                        return true;    /* rate-limited: don't send yet! */
-                }
-        }
-
-        *last_oow_ack_time = tcp_time_stamp;
-
-not_rate_limited:
-        return false;   /* not rate-limited: go ahead, send dupack now! */
-}
+bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
+                          int mib_idx, u32 *last_oow_ack_time);
 
 static inline void tcp_mib_init(struct net *net)
 {
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 10d6bd93f229..7257eb206c07 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3321,6 +3321,36 @@ static int tcp_ack_update_window(struct sock *sk, const struct sk_buff *skb, u32
         return flag;
 }
 
+/* Return true if we're currently rate-limiting out-of-window ACKs and
+ * thus shouldn't send a dupack right now. We rate-limit dupacks in
+ * response to out-of-window SYNs or ACKs to mitigate ACK loops or DoS
+ * attacks that send repeated SYNs or ACKs for the same connection. To
+ * do this, we do not send a duplicate SYNACK or ACK if the remote
+ * endpoint is sending out-of-window SYNs or pure ACKs at a high rate.
+ */
+bool tcp_oow_rate_limited(struct net *net, const struct sk_buff *skb,
+                          int mib_idx, u32 *last_oow_ack_time)
+{
+        /* Data packets without SYNs are not likely part of an ACK loop. */
+        if ((TCP_SKB_CB(skb)->seq != TCP_SKB_CB(skb)->end_seq) &&
+            !tcp_hdr(skb)->syn)
+                goto not_rate_limited;
+
+        if (*last_oow_ack_time) {
+                s32 elapsed = (s32)(tcp_time_stamp - *last_oow_ack_time);
+
+                if (0 <= elapsed && elapsed < sysctl_tcp_invalid_ratelimit) {
+                        NET_INC_STATS_BH(net, mib_idx);
+                        return true;    /* rate-limited: don't send yet! */
+                }
+        }
+
+        *last_oow_ack_time = tcp_time_stamp;
+
+not_rate_limited:
+        return false;   /* not rate-limited: go ahead, send dupack now! */
+}
+
 /* RFC 5961 7 [ACK Throttling] */
 static void tcp_send_challenge_ack(struct sock *sk, const struct sk_buff *skb)
 {