Add per-interface counter for invalid checksum.

This patch adds a per-device counter for invalid checksum as
well as a simple packet counter.

src/decode.h

@@ -421,6 +421,9 @@ typedef struct Packet_
     uint8_t *ext_pkt;
     uint32_t pktlen;
 
+    /* Incoming interface */
+    struct LiveDevice_ *livedev;
+
     PacketAlerts alerts;
 
     /** packet number in the pcap file, matches wireshark */
@@ -574,6 +577,7 @@ typedef struct DecodeThreadVars_
     SCMutexInit(&(p)->tunnel_mutex, NULL); \
     PACKET_RESET_CHECKSUMS((p)); \
     (p)->pkt = ((uint8_t *)(p)) + sizeof(Packet); \
+    (p)->livedev = NULL; \
 }
 #else
 #define PACKET_INITIALIZE(p) { \
@@ -583,6 +587,7 @@ typedef struct DecodeThreadVars_
     SCMutexInit(&(p)->cuda_mutex, NULL); \
     SCCondInit(&(p)->cuda_cond, NULL); \
     (p)->pkt = ((uint8_t *)(p)) + sizeof(Packet); \
+    (p)->livedev = NULL; \
 }
 #endif
 
@@ -649,6 +654,7 @@ typedef struct DecodeThreadVars_
         (p)->next = NULL;                       \
         (p)->prev = NULL;                       \
         (p)->root = NULL;                       \
+        (p)->livedev = NULL;                      \
         PACKET_RESET_CHECKSUMS((p));            \
         PACKET_PROFILING_RESET((p));            \
     } while (0)
@@ -887,7 +893,7 @@ void AddressDebugPrint(Address *);
 #define PKT_TUNNEL                      0x1000
 #define PKT_TUNNEL_VERDICTED            0x2000
 
-#define PKT_IGNORE_CHECKSUM         0x4000    /**< Packet checksum is not computed (TX packet for example) */
+#define PKT_IGNORE_CHECKSUM             0x4000    /**< Packet checksum is not computed (TX packet for example) */
 
 /** \brief return 1 if the packet is a pseudo packet */
 #define PKT_IS_PSEUDOPKT(p) ((p)->flags & PKT_PSEUDO_STREAM_END)

src/stream-tcp.c

@@ -48,6 +48,7 @@
 #include "util-unittest.h"
 #include "util-print.h"
 #include "util-debug.h"
+#include "util-device.h"
 
 #include "stream-tcp-private.h"
 #include "stream-tcp-reassemble.h"
@@ -3848,6 +3849,9 @@ static inline int StreamTcpValidateChecksum(Packet *p)
     if (p->tcpvars.comp_csum != p->tcph->th_sum) {
         ret = 0;
         SCLogDebug("Checksum of received packet %p is invalid",p);
+        if (p->livedev) {
+            SC_ATOMIC_ADD(p->livedev->invalid_checksums, 1);
+        }
     }
 
     return ret;

src/util-checksum.c

@@ -25,6 +25,8 @@
 
 #include "suricata-common.h"
 
+#include "util-checksum.h"
+
 int ReCalculateChecksum(Packet *p)
 {
     if (PKT_IS_IPV4(p)) {
@@ -57,3 +59,27 @@ int ReCalculateChecksum(Packet *p)
 
     return 0;
 }
+
+
+int ChecksumAutoModeCheck(uint32_t thread_count,
+                                  uint32_t iface_count,
+                                  uint32_t iface_fail)
+{
+    if (thread_count == CHECKSUM_SAMPLE_COUNT) {
+        if (iface_fail != 0) {
+            if ((iface_count / iface_fail) < CHECKSUM_INVALID_RATIO) {
+                SCLogInfo("More than 1/10 of invalid checksum, assuming checksum offloading is used (%d/%d)",
+                          iface_fail,
+                          iface_count);
+                return 1;
+            } else {
+                SCLogInfo("Less than 1/10 of invalid checksum, assuming checksum offloading is NOT used (%d/%d)",
+                        iface_fail,
+                        iface_count);
+            }
+        } else {
+            SCLogInfo("No packet with invalid checksum, assuming checksum offloading is NOT used");
+        }
+    }
+    return 0;
+}

src/util-checksum.h

@@ -24,7 +24,14 @@
 #ifndef __UTIL_CHECKSUM_H__
 #define __UTIL_CHECKSUM_H__
 
-
 int ReCalculateChecksum(Packet *p);
+int ChecksumAutoModeCheck(uint32_t thread_count,
+                           uint32_t iface_count,
+                           uint32_t iface_fail);
+
+/* constant linked with detection of interface with
+ * invalid checksums */
+#define CHECKSUM_SAMPLE_COUNT 1000
+#define CHECKSUM_INVALID_RATIO 5
 
 #endif

src/util-device.c

@@ -48,6 +48,9 @@ int LiveRegisterDevice(char *dev)
     }
 
     pd->dev = SCStrdup(dev);
+    SC_ATOMIC_INIT(pd->pkts);
+    SC_ATOMIC_INIT(pd->invalid_checksums);
+    pd->ignore_checksum = 0;
     TAILQ_INSERT_TAIL(&live_devices, pd, next);
 
     SCLogDebug("Pcap device \"%s\" registered.", dev);

src/util-device.h

@@ -23,6 +23,9 @@
 /** storage for live device names */
 typedef struct LiveDevice_ {
     char *dev;  /**< the device (e.g. "eth0") */
+    int ignore_checksum;
+    SC_ATOMIC_DECLARE(uint32_t, pkts);
+    SC_ATOMIC_DECLARE(uint32_t, invalid_checksums);
     TAILQ_ENTRY(LiveDevice_) next;
 } LiveDevice;