From: Victor Julien <victor@inliniac.net>
Date: Fri, 27 Jan 2017 09:03:39 +0000 (+0100)
Subject: mtu: track max mtu for capture devices
X-Git-Tag: suricata-3.2.1~32
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1ba15d3721343a670436ea7363b050702bb2f043;p=thirdparty%2Fsuricata.git

mtu: track max mtu for capture devices
---

diff --git a/src/decode.h b/src/decode.h
index b84f466e0a..aa21f1a8ad 100644
--- a/src/decode.h
+++ b/src/decode.h
@@ -594,7 +594,11 @@ typedef struct Packet_
 #endif
 Packet;
 
-#define DEFAULT_PACKET_SIZE (1500 + ETHERNET_HEADER_LEN)
+/** highest mtu of the interfaces we monitor */
+extern int g_default_mtu;
+#define DEFAULT_MTU 1500
+
+#define DEFAULT_PACKET_SIZE (DEFAULT_MTU + ETHERNET_HEADER_LEN)
 /* storage: maximum ip packet size + link header */
 #define MAX_PAYLOAD_SIZE (IPV6_HEADER_LEN + 65536 + 28)
 uint32_t default_packet_size;
diff --git a/src/suricata.c b/src/suricata.c
index dc5f55c48f..2d2a5c2872 100644
--- a/src/suricata.c
+++ b/src/suricata.c
@@ -213,6 +213,9 @@ int g_detect_disabled = 0;
 /** set caps or not */
 int sc_set_caps = FALSE;
 
+/** highest mtu of the interfaces we monitor */
+int g_default_mtu = 0;
+
 int EngineModeIsIPS(void)
 {
     return (g_engine_mode == ENGINE_MODE_IPS);
@@ -2360,6 +2363,8 @@ static int ConfigGetCaptureValue(SCInstance *suri)
                             dev[len-1] = '\0';
                         }
                     }
+                    int mtu = GetIfaceMTU(dev);
+                    g_default_mtu = MAX(mtu, g_default_mtu);
 
                     unsigned int iface_max_packet_size = GetIfaceMaxPacketSize(dev);
                     if (iface_max_packet_size > default_packet_size)
@@ -2369,6 +2374,7 @@ static int ConfigGetCaptureValue(SCInstance *suri)
                     break;
                 /* fall through */
             default:
+                g_default_mtu = DEFAULT_MTU;
                 default_packet_size = DEFAULT_PACKET_SIZE;
         }
     } else {