Match packet mask against 16 signature masks at once using SIMD instructions for SSE3 and up.

src/detect-engine-siggroup.c

@@ -175,6 +175,17 @@ void SigGroupHeadFree(SigGroupHead *sgh)
 
     PatternMatchDestroyGroup(sgh);
 
+    if (sgh->mask_array != NULL) {
+        /* mask is aligned */
+        SCFreeAligned(sgh->mask_array);
+        sgh->mask_array = NULL;
+    }
+
+    if (sgh->head_array != NULL) {
+        SCFree(sgh->head_array);
+        sgh->head_array = NULL;
+    }
+
     if (sgh->match_array != NULL) {
         detect_siggroup_matcharray_free_cnt++;
         detect_siggroup_matcharray_memory -= (sgh->sig_cnt * sizeof(Signature *));
@@ -1582,6 +1593,7 @@ int SigGroupHeadBuildHeadArray(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
         return 0;
 
     BUG_ON(sgh->head_array != NULL);
+    BUG_ON(sgh->mask_array != NULL);
 
     sgh->head_array = SCMalloc(sgh->sig_cnt * sizeof(SignatureHeader));
     if (sgh->head_array == NULL)
@@ -1592,6 +1604,19 @@ int SigGroupHeadBuildHeadArray(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
     detect_siggroup_matcharray_init_cnt++;
     detect_siggroup_matcharray_memory += (sgh->sig_cnt * sizeof(SignatureHeader *));
 
+    /* mask array is 16 byte aligned for SIMD checking, also we always
+     * alloc a multiple of 16 bytes */
+    int cnt = sgh->sig_cnt;
+    if (cnt % 16 != 0) {
+        cnt += (16 - (cnt % 16));
+    }
+
+    sgh->mask_array = SCMallocAligned((cnt * sizeof(SignatureMask)), 16);
+    if (sgh->mask_array == NULL)
+        return -1;
+
+    memset(sgh->mask_array, 0, (cnt * sizeof(SignatureMask)));
+
     for (sig = 0; sig < sgh->sig_cnt; sig++) {
         s = sgh->match_array[sig];
         if (s == NULL)
@@ -1602,6 +1627,7 @@ int SigGroupHeadBuildHeadArray(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
         sgh->head_array[idx].hdr_copy3 = s->hdr_copy3;
         sgh->head_array[idx].full_sig = s;
 
+        sgh->mask_array[idx] = s->mask;
         idx++;
     }
 

src/detect.c

@@ -672,6 +672,8 @@ int SigLoadSignatures(DetectEngineCtx *de_ctx, char *sig_file)
     SCReturnInt(ret);
 }
 
+#include "util-vector.h"
+
 /**
  *  \brief build an array of signatures that will be inspected
  *
@@ -697,33 +699,49 @@ static void SigMatchSignaturesBuildMatchArray(DetectEngineCtx *de_ctx,
         DetectEngineThreadCtx *det_ctx, Packet *p, SignatureMask mask,
         uint16_t alproto)
 {
-    uint32_t i;
+    uint32_t u;
+    uint32_t bm; /* bit mask, 16 bits used */
+
+#if defined(__SSE3__)
+    Vector pm, sm, r1, r2;
+    /* load the packet mask into each byte of the vector */
+    pm.v = _mm_set1_epi8(mask);
+#endif
 
     /* reset previous run */
     det_ctx->match_array_cnt = 0;
 
-    for (i = 0; i < det_ctx->sgh->sig_cnt; i++) {
-        SignatureHeader *s = &det_ctx->sgh->head_array[i];
-
-        if ((mask & s->mask) != s->mask) {
-            SCLogDebug("Mask mismatch. mask %02X, s->mask %02x, after AND %02x", mask, s->mask, mask & s->mask);
+    for (u = 0; u < det_ctx->sgh->sig_cnt; u += 16) {
+        SigIntId x;
+        int bitno = 0;
+#if defined(__SSE3__)
+        /* load a batch of masks */
+        sm.v = _mm_load_si128((const __m128i *)&det_ctx->sgh->mask_array[u]);
+        /* logical AND them with the packet's mask */
+        r1.v = _mm_and_si128(pm.v, sm.v);
+        /* compare the result with the original mask */
+        r2.v = _mm_cmpeq_epi8(sm.v, r1.v);
+        /* convert into a bitarray */
+        bm = _mm_movemask_epi8(r2.v);
+#else
+        bm = 0;
+        for (x = u; x < det_ctx->sgh->sig_cnt && bitno < 16; x++, bitno++) {
+            int r = ((mask & det_ctx->sgh->mask_array[x]) == det_ctx->sgh->mask_array[x]);
+            bm |= (r << bitno);
+        }
+        SCLogDebug("bm %04X", bm);
+#endif
+        if (bm == 0) {
             continue;
         }
-        SCLogDebug("Mask match. mask %02X, s->mask %02x, after AND %02x", mask, s->mask, mask & s->mask);
 
-#if 0
-        if (!(p->flags & PKT_HAS_FLOW) && s->init_flags & SIG_FLAG_FLOW) {
-            SCLogDebug("flow in sig but not in packet");
+        bitno = 0;
+        for (x = u; x < det_ctx->sgh->sig_cnt && bitno < 16; x++, bitno++) {
+            if (!(bm & (1 << bitno))) {
                 continue;
             }
+            SignatureHeader *s = &det_ctx->sgh->head_array[x];
 
-        /* filter out the sigs that inspect the payload, if packet
-           no payload inspection flag is set*/
-        if ((p->flags & PKT_NOPAYLOAD_INSPECTION) && (s->init_flags & SIG_FLAG_PAYLOAD)) {
-            SCLogDebug("no payload inspection enabled and sig has payload portion.");
-            continue;
-        }
-#endif
             /* if the sig has alproto and the session as well they should match */
             if (s->flags & SIG_FLAG_APPLAYER && s->alproto != ALPROTO_UNKNOWN && s->alproto != alproto) {
                 if (s->alproto == ALPROTO_DCERPC) {
@@ -865,6 +883,7 @@ static void SigMatchSignaturesBuildMatchArray(DetectEngineCtx *de_ctx,
                 det_ctx->match_array_cnt++;
             }
     }
+}
 
 /**
  *  \brief Get the SigGroupHead for a packet.
@@ -2125,6 +2144,7 @@ int SigAddressPrepareStage1(DetectEngineCtx *de_ctx) {
         }
 #endif /* DEBUG */
 
+        SignatureCreateMask(tmp_s);
 
         for (gr = tmp_s->src.ipv4_head; gr != NULL; gr = gr->next) {
             if (SigGroupHeadAppendSig(de_ctx, &gr->sh, tmp_s) < 0) {
@@ -2146,8 +2166,6 @@ int SigAddressPrepareStage1(DetectEngineCtx *de_ctx) {
             cnt++;
         }
 
-        SignatureCreateMask(tmp_s);
-
         de_ctx->sig_cnt++;
     }
 

src/detect.h

@@ -871,11 +871,17 @@ typedef struct SigGroupHead_ {
 
     uint16_t mpm_content_maxlen;
 
+    SignatureMask *mask_array;
     /** chunk of memory containing the "header" part of each
      *  signature ordered as an array. Used to pre-filter the
      *  signatures to be inspected in a cache efficient way. */
     SignatureHeader *head_array;
 
+    /** chunk of memory containing the "header" part of each
+     *  signature ordered as an array. Used to pre-filter the
+     *  signatures to be inspected in a cache efficient way. */
+    //SignatureHeader *head_array;
+
     /* pattern matcher instances */
     MpmCtx *mpm_ctx;
     MpmCtx *mpm_stream_ctx;

src/util-vector.h

@@ -24,7 +24,7 @@
 #ifndef __UTIL_VECTOR_H__
 #define __UTIL_VECTOR_H__
 
-#ifdef defined(__SSE3__)
+#if defined(__SSE3__)
 
 #include <pmmintrin.h>