aboutsummaryrefslogtreecommitdiff
path: root/include/net/tcp.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r--include/net/tcp.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 8983386356a..6bc4b8148ca 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -782,6 +782,21 @@ static inline __u32 tcp_current_ssthresh(const struct sock *sk)
/* Use define here intentionally to get WARN_ON location shown at the caller */
#define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out)
+/*
+ * Convert RFC3390 larger initial windows into an equivalent number of packets.
+ *
+ * John Heffner states:
+ *
+ * The RFC specifies a window of no more than 4380 bytes
+ * unless 2*MSS > 4380. Reading the pseudocode in the RFC
+ * is a bit misleading because they use a clamp at 4380 bytes
+ * rather than a multiplier in the relevant range.
+ */
+static inline u32 rfc3390_bytes_to_packets(const u32 bytes)
+{
+ return bytes <= 1095 ? 4 : (bytes > 1460 ? 2 : 3);
+}
+
extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh);
extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst);