detect: add igmp.type keyword

src/Makefile.am

@@ -229,6 +229,7 @@ noinst_HEADERS = \
 	detect-icode.h \
 	detect-id.h \
 	detect-igmphdr.h \
+	detect-igmp-type.h \
 	detect-ipaddr.h \
 	detect-ipopts.h \
 	detect-ipproto.h \
@@ -808,6 +809,7 @@ libsuricata_c_a_SOURCES = \
 	detect-icode.c \
 	detect-id.c \
 	detect-igmphdr.c \
+	detect-igmp-type.c \
 	detect-ipaddr.c \
 	detect-ipopts.c \
 	detect-ipproto.c \

src/detect-engine-register.c

@@ -155,6 +155,7 @@
 #include "detect-icmp-seq.h"
 #include "detect-icmpv4hdr.h"
 #include "detect-igmphdr.h"
+#include "detect-igmp-type.h"
 #include "detect-dce-iface.h"
 #include "detect-dce-opnum.h"
 #include "detect-dce-stub-data.h"
@@ -666,6 +667,7 @@ void SigTableSetup(void)
     DetectIcmpSeqRegister();
     DetectIcmpv4HdrRegister();
     DetectIGMPHdrRegister();
+    DetectIGMPTypeRegister();
     DetectDceIfaceRegister();
     DetectDceOpnumRegister();
     DetectDceStubDataRegister();

src/detect-engine-register.h

@@ -50,6 +50,7 @@ enum DetectKeywordId {
     DETECT_ICMP_SEQ,
     DETECT_ICMPV4HDR,
     DETECT_IGMPHDR,
+    DETECT_IGMP_TYPE,
     DETECT_DSIZE,
 
     DETECT_FLOW,

src/detect-igmp-type.c

@@ -0,0 +1,164 @@
+/* Copyright (C) 2026 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/**
+ * \file
+ *
+ * Implements igmp.type keyword support
+ */
+
+#include "suricata-common.h"
+#include "decode.h"
+
+#include "detect.h"
+#include "detect-parse.h"
+#include "detect-engine-prefilter-common.h"
+#include "detect-engine-build.h"
+
+#include "detect-igmp-type.h"
+#include "detect-engine-uint.h"
+
+#include "util-byte.h"
+#include "util-unittest.h"
+#include "util-unittest-helper.h"
+#include "util-debug.h"
+
+static int DetectIGMPTypeMatch(
+        DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *);
+static int DetectIGMPTypeSetup(DetectEngineCtx *, Signature *, const char *);
+void DetectIGMPTypeFree(DetectEngineCtx *, void *);
+
+static int PrefilterSetupIGMPType(DetectEngineCtx *de_ctx, SigGroupHead *sgh);
+static bool PrefilterIGMPTypeIsPrefilterable(const Signature *s);
+
+/**
+ * \brief Registration function for igmp.type keyword
+ */
+void DetectIGMPTypeRegister(void)
+{
+    sigmatch_table[DETECT_IGMP_TYPE].name = "igmp.type";
+    sigmatch_table[DETECT_IGMP_TYPE].desc = "match on a specific IGMP type";
+    sigmatch_table[DETECT_IGMP_TYPE].url = "/rules/header-keywords.html#igmp.type";
+    sigmatch_table[DETECT_IGMP_TYPE].Match = DetectIGMPTypeMatch;
+    sigmatch_table[DETECT_IGMP_TYPE].Setup = DetectIGMPTypeSetup;
+    sigmatch_table[DETECT_IGMP_TYPE].Free = DetectIGMPTypeFree;
+    sigmatch_table[DETECT_IGMP_TYPE].flags = SIGMATCH_INFO_UINT8;
+    sigmatch_table[DETECT_IGMP_TYPE].SupportsPrefilter = PrefilterIGMPTypeIsPrefilterable;
+    sigmatch_table[DETECT_IGMP_TYPE].SetupPrefilter = PrefilterSetupIGMPType;
+}
+
+/**
+ * \brief This function is used to match igmp.type rule option
+ *
+ * \param t pointer to thread vars
+ * \param det_ctx pointer to the pattern matcher thread
+ * \param p pointer to the current packet
+ * \param m pointer to the sigmatch that we will cast into DetectU8Data
+ *
+ * \retval 0 no match
+ * \retval 1 match
+ */
+static int DetectIGMPTypeMatch(
+        DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
+{
+    DEBUG_VALIDATE_BUG_ON(PKT_IS_PSEUDOPKT(p));
+
+    if (!PacketIsIGMP(p)) {
+        /* Packet not IGMP */
+        return 0;
+    }
+
+    const IGMPHdr *igmph = PacketGetIGMP(p);
+    uint8_t type = igmph->type;
+    const DetectU8Data *itd = (const DetectU8Data *)ctx;
+    return DetectU8Match(type, itd);
+}
+
+/**
+ * \brief this function is used to add the parsed igmp.type data into the current signature
+ *
+ * \param de_ctx pointer to the Detection Engine Context
+ * \param s pointer to the Current Signature
+ * \param str pointer to the user provided igmp.type options
+ *
+ * \retval 0 on Success
+ * \retval -1 on Failure
+ */
+static int DetectIGMPTypeSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
+{
+    if (!(DetectProtoContainsProto(&s->proto, IPPROTO_IGMP)))
+        return -1;
+
+    DetectU8Data *itd = DetectU8Parse(str);
+    if (itd == NULL)
+        return -1;
+
+    if (SCSigMatchAppendSMToList(
+                de_ctx, s, DETECT_IGMP_TYPE, (SigMatchCtx *)itd, DETECT_SM_LIST_MATCH) == NULL) {
+        DetectIGMPTypeFree(de_ctx, itd);
+        return -1;
+    }
+    s->proto.flags |= DETECT_PROTO_IPV4;
+    s->flags |= SIG_FLAG_REQUIRE_PACKET;
+
+    return 0;
+}
+
+/**
+ * \brief this function will free memory associated with DetectU8Data
+ *
+ * \param ptr pointer to DetectU8Data
+ */
+void DetectIGMPTypeFree(DetectEngineCtx *de_ctx, void *ptr)
+{
+    DetectU8Data *itd = (DetectU8Data *)ptr;
+    SCDetectU8Free(itd);
+}
+
+/* prefilter code
+ *
+ * Prefilter uses the U8Hash logic, where we setup a 256 entry array
+ * for each IGMP type. Each array element has the list of signatures
+ * that need to be inspected. */
+
+static void PrefilterPacketIGMPTypeMatch(
+        DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
+{
+    DEBUG_VALIDATE_BUG_ON(PKT_IS_PSEUDOPKT(p));
+
+    if (PacketIsIGMP(p)) {
+        const IGMPHdr *igmph = PacketGetIGMP(p);
+        uint8_t type = igmph->type;
+        const PrefilterPacketU8HashCtx *h = pectx;
+        const SigsArray *sa = h->array[type];
+        if (sa) {
+            PrefilterAddSids(&det_ctx->pmq, sa->sigs, sa->cnt);
+        }
+    }
+}
+
+static int PrefilterSetupIGMPType(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
+{
+    return PrefilterSetupPacketHeaderU8Hash(de_ctx, sgh, DETECT_IGMP_TYPE,
+            SIG_MASK_REQUIRE_REAL_PKT, PrefilterPacketU8Set, PrefilterPacketU8Compare,
+            PrefilterPacketIGMPTypeMatch);
+}
+
+static bool PrefilterIGMPTypeIsPrefilterable(const Signature *s)
+{
+    return PrefilterIsPrefilterableById(s, DETECT_IGMP_TYPE);
+}

src/detect-igmp-type.h

@@ -0,0 +1,29 @@
+/* Copyright (C) 2026 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/**
+ * \file
+ *
+ */
+
+#ifndef SURICATA_DETECT_IGMP_TYPE_H
+#define SURICATA_DETECT_IGMP_TYPE_H
+
+/* prototypes */
+void DetectIGMPTypeRegister(void);
+
+#endif /* SURICATA_DETECT_IGMP_TYPE_H */