From: Sergey Matveev <stargrave@stargrave.org>
Date: Mon, 14 Sep 2015 09:16:04 +0000 (+0300)
Subject: Simple optimization for TCP buffer check
X-Git-Tag: 4.0^2~10
X-Git-Url: http://www.git.cypherpunks.ru/?p=govpn.git;a=commitdiff_plain;h=d20ad6088e1b9a90cebef28901ed3ece9f970f15

Simple optimization for TCP buffer check

Signed-off-by: Sergey Matveev <stargrave@stargrave.org>
---

diff --git a/src/govpn/cmd/govpn-client/tcp.go b/src/govpn/cmd/govpn-client/tcp.go
index 49d3ae9..511955c 100644
--- a/src/govpn/cmd/govpn-client/tcp.go
+++ b/src/govpn/cmd/govpn-client/tcp.go
@@ -136,6 +136,9 @@ TransportCycle:
 		}
 		prev += n
 	CheckMore:
+		if prev < govpn.MinPktLength {
+			continue
+		}
 		i = bytes.Index(buf[:prev], nonceExpectation)
 		if i == -1 {
 			continue
diff --git a/src/govpn/cmd/govpn-server/tcp.go b/src/govpn/cmd/govpn-server/tcp.go
index 8aedfa9..d8deaa1 100644
--- a/src/govpn/cmd/govpn-server/tcp.go
+++ b/src/govpn/cmd/govpn-server/tcp.go
@@ -170,6 +170,9 @@ func handleTCP(conn net.Conn) {
 		}
 		prev += n
 	CheckMore:
+		if prev < govpn.MinPktLength {
+			continue
+		}
 		i = bytes.Index(buf[:prev], nonceExpectation)
 		if i == -1 {
 			continue
diff --git a/src/govpn/peer.go b/src/govpn/peer.go
index f5f917a..e666b47 100644
--- a/src/govpn/peer.go
+++ b/src/govpn/peer.go
@@ -24,6 +24,8 @@ const (
 	PktSizeSize = 2
 	// Heartbeat rate, relative to Timeout
 	TimeoutHeartbeat = 4
+	// Minimal valid packet length: 2+
+	MinPktLength = 2 + 16 + 8
 )
 
 func newNonceCipher(key *[32]byte) *xtea.Cipher {