nfqws: message for seqovl pos => seqovl

blockcheck.sh

@@ -45,7 +45,6 @@ HTTP_PORT=${HTTP_PORT:-80}
 HTTPS_PORT=${HTTPS_PORT:-443}
 QUIC_PORT=${QUIC_PORT:-443}
 UNBLOCKED_DOM=${UNBLOCKED_DOM:-iana.org}
-[ "$CURL_VERBOSE" = 1 ] && CURL_CMD=1
 
 HDRTEMP=/tmp/zapret-hdr.txt
 
@@ -792,7 +791,7 @@ pktws_ipt_prepare()
 			# disable PF to avoid interferences
 			pf_is_avail && pfctl -qd
 			for ip in $3; do
-				IPFW_ADD divert $IPFW_DIVERT_PORT $1 from me to $ip $2 proto ip${IPV} out not diverted not sockarg
+				IPFW_ADD divert $IPFW_DIVERT_PORT $1 from me to $ip $2 proto ip${IPV} out not diverted
 			done
 			;;
 		opf)
@@ -867,7 +866,7 @@ pktws_ipt_prepare_tcp()
 			;;
 		ipfw)
 			for ip in $2; do
-				IPFW_ADD divert $IPFW_DIVERT_PORT tcp from $ip $1 to me proto ip${IPV} tcpflags syn,ack in not diverted not sockarg
+				IPFW_ADD divert $IPFW_DIVERT_PORT tcp from $ip $1 to me proto ip${IPV} tcpflags syn,ack in not diverted
 			done
 			;;
 	esac
@@ -994,7 +993,6 @@ ws_curl_test()
 	# $2 - test function
 	# $3 - domain
 	# $4,$5,$6, ... - ws params
-
 	local code ws_start=$1 testf=$2 dom=$3
 	shift
 	shift
@@ -1088,7 +1086,7 @@ test_has_split()
 }
 test_has_fake()
 {
-	contains "$1" fake
+	[ "$1" = fake ] || starts_with "$1" fake,
 }
 warn_fool()
 {
@@ -1105,25 +1103,34 @@ pktws_curl_test_update_vary()
 	# $4 - desync mode
 	# $5,$6,... - strategy
 
-	local testf=$1 sec=$2 domain=$3 desync=$4 zerofake split fake
+	local testf=$1 sec=$2 domain=$3 desync=$4 proto zerofake= splits= pos fake ret=1
 	
 	shift; shift; shift; shift
 	
-	zerofake=http
+	proto=http
-	[ "$sec" = 0 ] || zerofake=tls
+	[ "$sec" = 0 ] || proto=tls
-	zerofake="--dpi-desync-fake-$zerofake=0x00000000"
+	test_has_fake $desync && zerofake="--dpi-desync-fake-$proto=0x00000000"
-	
+	test_has_split $desync && {
+		splits="method+2 midsld"
+		[ "$sec" = 0 ] || splits="1 midsld 1,midsld"
+	}
 	for fake in '' $zerofake ; do
-		for split in '' '--dpi-desync-split-pos=1' ; do
+		if [ -n "$splits" ]; then
-			pktws_curl_test_update $testf $domain --dpi-desync=$desync "$@" $fake $split && return 0
+			for pos in $splits ; do
-			# split-pos=1 is meaningful for DPIs searching for 16 03 in TLS. no reason to apply to http
+				pktws_curl_test_update $testf $domain --dpi-desync=$desync "$@" --dpi-desync-split-pos=$pos $fake && {
-			[ "$sec" = 1 ] || break
+					[ "$SCANLEVEL" = force ] || return 0
-			test_has_split $desync || break
+					ret=0
+				}
 			done
-		test_has_fake $desync || break
+		else
+			pktws_curl_test_update $testf $domain --dpi-desync=$desync "$@" $fake && {
+				[ "$SCANLEVEL" = force ] || return 0
+				ret=0
+			}
+		fi
 	done
 
-	return 1
+	return $ret
 }
 
 pktws_check_domain_http_bypass_()
@@ -1132,7 +1139,10 @@ pktws_check_domain_http_bypass_()
 	# $2 - encrypted test : 0 = plain, 1 - encrypted with server reply risk, 2 - encrypted without server reply risk
 	# $3 - domain
 
-	local tests='fake' ret ok ttls s f e desync pos fooling frag sec="$2" delta hostcase
+	local ok ttls s f f2 e desync pos fooling frag sec="$2" delta splits
+	local need_split need_disorder need_fakedsplit need_fakeddisorder need_fake need_wssize
+	local splits_http='method+2 midsld method+2,midsld'
+	local splits_tls='2 1 sniext+1 sniext+4 host+1 midsld 1,midsld 1,sniext+1,host+1,midsld-2,midsld,midsld+2,endhost-1'
 
 	[ "$sec" = 0 ] && {
 		for s in '--hostcase' '--hostspell=hoSt' '--hostnospace' '--domcase'; do
@@ -1140,74 +1150,62 @@ pktws_check_domain_http_bypass_()
 		done
 	}
 
-	s="--dpi-desync=split2"
-	ok=0
-	pktws_curl_test_update $1 $3 $s
-	ret=$?
-	[ "$ret" = 0 ] && {
-		[ "$SCANLEVEL" = quick ] && return
-		ok=1
-	}
-	[ "$ret" != 0 -o "$SCANLEVEL" = force ] && {
-		if [ "$sec" = 0 ]; then
-			pktws_curl_test_update $1 $3 $s --hostcase && {
-				[ "$SCANLEVEL" = quick ] && return
-				ok=1
-			}
-			for pos in method host; do
-				for hostcase in '' '--hostcase'; do
-					pktws_curl_test_update $1 $3 $s --dpi-desync-split-http-req=$pos $hostcase && {
-						[ "$SCANLEVEL" = quick ] && return
-						ok=1
-					}
-				done
-			done
-		else
-			for pos in sni sniext; do
-				pktws_curl_test_update $1 $3 $s --dpi-desync-split-tls=$pos && {
-					[ "$SCANLEVEL" = quick ] && return
-					ok=1
-				}
-			done
-		fi
-		for pos in 1 3 4 5 10 50; do
-			s="--dpi-desync=split2 --dpi-desync-split-pos=$pos"
-			if pktws_curl_test_update $1 $3 $s; then
-				[ "$SCANLEVEL" = quick ] && return
-				ok=1
-				[ "$SCANLEVEL" = force ] || break
-			elif [ "$sec" = 0 ]; then
-				pktws_curl_test_update $1 $3 $s --hostcase && [ "$SCANLEVEL" = quick ] && return
-			fi
-		done
-	}
-	[ "$ok" = 1 -a "$SCANLEVEL" != force ] || tests="$tests split fake,split2 fake,split"
-
-	pktws_curl_test_update $1 $3 --dpi-desync=disorder2
-	ret=$?
-	[ "$ret" = 0 -a "$SCANLEVEL" = quick ] && return
-	[ "$ret" != 0 -o "$SCANLEVEL" = force ] && {
-	    pktws_curl_test_update $1 $3 --dpi-desync=disorder2 --dpi-desync-split-pos=1
-	    ret=$?
-	    [ "$ret" = 0 -a "$SCANLEVEL" = quick ] && return
-	}
-	[ "$ret" != 0 -o "$SCANLEVEL" = force ] && tests="$tests disorder fake,disorder2 fake,disorder"
-
 	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	need_wssize=1
 	for e in '' '--wssize 1:6'; do
+		need_split=
+		need_disorder=
+
 		[ -n "$e" ] && {
 			pktws_curl_test_update $1 $3 $e && [ "$SCANLEVEL" = quick ] && return
-			for desync in split2 disorder2; do
-				pktws_curl_test_update_vary $1 $2 $3 $desync $e && [ "$SCANLEVEL" = quick ] && return
-			done
 		}
-		for desync in $tests; do
+
+		for desync in multisplit multidisorder; do
+			ok=0
+			splits="$splits_http"
+			[ "$sec" = 0 ] || splits="$splits_tls"
+			for pos in $splits; do
+				pktws_curl_test_update $1 $3 --dpi-desync=$desync --dpi-desync-split-pos=$pos $e && {
+					[ "$SCANLEVEL" = quick ] && return
+					ok=1
+					need_wssize=0
+					[ "$SCANLEVEL" = force ] || break
+				}
+			done
+			[ "$ok" = 1 -a "$SCANLEVEL" != force ] || {
+				case $desync in
+					multisplit)
+						need_split=1
+						;;
+					multidisorder)
+						need_disorder=1
+						;;
+				esac
+			}
+		done
+
+		need_fakedsplit=1
+		need_fakeddisorder=1
+		need_fake=1
+		for desync in fake ${need_split:+fakedsplit fake,multisplit fake,fakedsplit} ${need_disorder:+fakeddisorder fake,multidisorder fake,fakeddisorder}; do
+			[ "$need_fake" = 0 ] && test_has_fake "$desync" && continue
+			[ "$need_fakedsplit" = 0 ] && contains "$desync" fakedsplit && continue
+			[ "$need_fakeddisorder" = 0 ] && contains "$desync" fakeddisorder && continue
+			ok=0
 			for ttl in $ttls; do
 				pktws_curl_test_update_vary $1 $2 $3 $desync --dpi-desync-ttl=$ttl $e && {
 					[ "$SCANLEVEL" = quick ] && return
+					ok=1
+					need_wssize=0
 					break
 				}
 			done
+			# only skip tests if TTL succeeded. do not skip if TTL failed but fooling succeeded
+			[ $ok = 1 -a "$SCANLEVEL" != force ] && {
+				[ "$desync" = fake ] && need_fake=0
+				[ "$desync" = fakedsplit ] && need_fakedsplit=0
+				[ "$desync" = fakeddisorder ] && need_fakeddisorder=0
+			}
 			f=
 			[ "$UNAME" = "OpenBSD" ] || f="badsum"
 			f="$f badseq datanoack md5sig"
@@ -1216,37 +1214,68 @@ pktws_check_domain_http_bypass_()
 				pktws_curl_test_update_vary $1 $2 $3 $desync --dpi-desync-fooling=$fooling $e && {
 					warn_fool $fooling
 					[ "$SCANLEVEL" = quick ] && return
+					need_wssize=0
 				}
 			done
 		done
+
 		[ "$IPV" = 6 ] && {
-			f="hopbyhop hopbyhop,split2 hopbyhop,disorder2 destopt destopt,split2 destopt,disorder2"
+			f="hopbyhop ${need_split:+hopbyhop,multisplit} ${need_disorder:+hopbyhop,multidisorder} destopt ${need_split:+destopt,multisplit} ${need_disorder:+destopt,multidisorder}"
-			[ -n "$IP6_DEFRAG_DISABLE" ] && f="$f ipfrag1 ipfrag1,split2 ipfrag1,disorder2"
+			[ -n "$IP6_DEFRAG_DISABLE" ] && f="$f ipfrag1 ${need_split:+ ipfrag1,multisplit} ${need_disorder:+ ipfrag1,multidisorder}"
 			for desync in $f; do
-				pktws_curl_test_update_vary $1 $2 $3 $desync $e && [ "$SCANLEVEL" = quick ] && return
+				pktws_curl_test_update_vary $1 $2 $3 $desync $e && {
+					[ "$SCANLEVEL" = quick ] && return
+					need_wssize=0
+				}
 			done
 		}
 
-		for desync in split2 disorder2; do
+		[ "$need_split" = 1 ] && {
-			s="--dpi-desync=$desync"
+			# relative markers can be anywhere, even in subsequent packets. first packet can be MTU-full.
+			# make additional split pos "10" to guarantee enough space for seqovl and likely to be before midsld,sniext,...
+			# method is always expected in the beginning of the first packet
+			f="method+2 method+2,midsld"
+			[ "$sec" = 0 ] || f="10 10,sniext+1 10,sniext+4 10,midsld"
+			for pos in $f; do
+				pktws_curl_test_update $1 $3 --dpi-desync=multisplit --dpi-desync-split-pos=$pos --dpi-desync-split-seqovl=1 $e && {
+					[ "$SCANLEVEL" = quick ] && return
+					need_wssize=0
+				}
+			done
+			[ "$sec" != 0 ] && pktws_curl_test_update $1 $3 --dpi-desync=multisplit --dpi-desync-split-pos=2 --dpi-desync-split-seqovl=336 --dpi-desync-split-seqovl-pattern="$ZAPRET_BASE/files/fake/tls_clienthello_iana_org.bin" $e && {
+				[ "$SCANLEVEL" = quick ] && return
+				need_wssize=0
+			}
+		}
+		[ "$need_disorder" = 1 ] && {
 			if [ "$sec" = 0 ]; then
-				for pos in method host; do
+				for pos in 'method+1 method+2' 'midsld-1 midsld' 'method+1 method+2,midsld'; do
-					pktws_curl_test_update $1 $3 $s --dpi-desync-split-seqovl=1 --dpi-desync-split-http-req=$pos $e && [ "$SCANLEVEL" = quick ] && return
+					f="$(extract_arg 1 $pos)"
+					f2="$(extract_arg 2 $pos)"
+					pktws_curl_test_update $1 $3 --dpi-desync=multidisorder --dpi-desync-split-pos=$f2 --dpi-desync-split-seqovl=$f $e && {
+						[ "$SCANLEVEL" = quick ] && return
+						need_wssize=0
+					}
 				done
 			else
-				for pos in sni sniext; do
+				for pos in '1 2' 'sniext sniext+1' 'sniext+3 sniext+4' 'midsld-1 midsld' '1 2,midsld'; do
-					pktws_curl_test_update $1 $3 $s --dpi-desync-split-seqovl=1 --dpi-desync-split-tls=$pos $e && [ "$SCANLEVEL" = quick ] && return
+					f=$(extract_arg 1 $pos)
-				done
+					f2=$(extract_arg 2 $pos)
-			fi
+					pktws_curl_test_update $1 $3 --dpi-desync=multidisorder --dpi-desync-split-pos=$f2 --dpi-desync-split-seqovl=$f $e && {
-			for pos in 2 3 4 5 10 50; do
+						[ "$SCANLEVEL" = quick ] && return
-				pktws_curl_test_update $1 $3 $s --dpi-desync-split-seqovl=$(($pos - 1)) --dpi-desync-split-pos=$pos $e && [ "$SCANLEVEL" = quick ] && return
+						need_wssize=0
-			done
-			[ "$sec" != 0 -a $desync = split2 ] && {
-				pktws_curl_test_update $1 $3 $s --dpi-desync-split-seqovl=336 --dpi-desync-split-seqovl-pattern="$ZAPRET_BASE/files/fake/tls_clienthello_iana_org.bin" $e && [ "$SCANLEVEL" = quick ] && return
 					}
 				done
+			fi
+		}
 
-		for desync in $tests; do
+		need_fakedsplit=1
+		need_fakeddisorder=1
+		need_fake=1
+		for desync in fake ${need_split:+fakedsplit fake,multisplit fake,fakedsplit} ${need_disorder:+fakeddisorder fake,multidisorder fake,fakeddisorder}; do
+			[ "$need_fake" = 0 ] && test_has_fake "$desync" && continue
+			[ "$need_fakedsplit" = 0 ] && contains "$desync" fakedsplit && continue
+			[ "$need_fakeddisorder" = 0 ] && contains "$desync" fakeddisorder && continue
 			ok=0
 			for delta in 1 2 3 4 5; do
 				pktws_curl_test_update_vary $1 $2 $3 $desync --dpi-desync-ttl=1 --dpi-desync-autottl=$delta $e && ok=1
@@ -1256,18 +1285,25 @@ pktws_check_domain_http_bypass_()
 				echo "WARNING ! although autottl worked it requires testing on multiple domains to find out reliable delta"
 				echo "WARNING ! if a reliable delta cannot be found it's a good idea not to use autottl"
 				[ "$SCANLEVEL" = quick ] && return
+				need_wssize=0
+				[ "$SCANLEVEL" = force ] || {
+					[ "$desync" = fake ] && need_fake=0
+					[ "$desync" = fakedsplit ] && need_fakedsplit=0
+					[ "$desync" = fakeddisorder ] && need_fakeddisorder=0
+				}
 			}			
 		done
 
 		s="http_iana_org.bin"
 		[ "$sec" = 0 ] || s="tls_clienthello_iana_org.bin"
-		for desync in syndata syndata,split2 syndata,disorder2 ; do
+		for desync in syndata ${need_split:+syndata,multisplit} ${need_disorder:+syndata,multidisorder} ; do
 			pktws_curl_test_update_vary $1 $2 $3 $desync $e && [ "$SCANLEVEL" = quick ] && return
 			pktws_curl_test_update_vary $1 $2 $3 $desync --dpi-desync-fake-syndata="$ZAPRET_BASE/files/fake/$s" $e && [ "$SCANLEVEL" = quick ] && return
 		done
 
 		# do not do wssize test for http and TLS 1.3. it's useless
 		[ "$sec" = 1 ] || break
+		[ "$SCANLEVEL" = force -o "$need_wssize" = 1 ] || break
 	done
 }
 pktws_check_domain_http_bypass()
@@ -1338,15 +1374,28 @@ tpws_check_domain_http_bypass_()
 	# $2 - encrypted test : 0 = plain, 1 - encrypted with server reply risk, 2 - encrypted without server reply risk
 	# $3 - domain
 
-	local s mss s2 s3 pos sec="$2"
+	local s mss s2 s3 oobdis pos sec="$2"
+	local splits_tls='2 1 sniext+1 sniext+4 host+1 midsld 1,midsld 1,sniext+1,host+1,midsld,endhost-1'
+	local splits_http='method+2 midsld method+2,midsld'
+
+	# simulteneous oob and disorder works properly only in linux. other systems retransmit oob byte without URG tcp flag and poison tcp stream.
+	[ "$UNAME" = Linux ] && oobdis='--oob --disorder'
 	if [ "$sec" = 0 ]; then
-		for s in '--hostcase' '--hostspell=hoSt' '--hostdot' '--hosttab' '--hostnospace' '--domcase' \
+		for s in '--hostcase' '--hostspell=hoSt' '--hostdot' '--hosttab' '--hostnospace' '--domcase' ; do
-			'--hostpad=1024' '--hostpad=2048' '--hostpad=4096' '--hostpad=8192' '--hostpad=16384' ; do
 			tpws_curl_test_update $1 $3 $s && [ "$SCANLEVEL" = quick ] && return
 		done
-		for s2 in '' '--oob' '--disorder' '--oob --disorder'; do
+		for s in 1024 2048 4096 8192 16384 ; do
-			for s in '--split-http-req=method' '--split-http-req=method --hostcase' '--split-http-req=host' '--split-http-req=host --hostcase' ; do
+			tpws_curl_test_update $1 $3 --hostpad=$s && [ "$SCANLEVEL" != force ] && {
-				tpws_curl_test_update $1 $3 $s $s2 && [ "$SCANLEVEL" = quick ] && return
+				[ "$SCANLEVEL" = quick ] && return
+				break
+			}
+		done
+		for s2 in '' '--hostcase' '--oob' '--disorder' ${oobdis:+"$oobdis"}; do
+			for s in $splits_http ; do
+				tpws_curl_test_update $1 $3 --split-pos=$s $s2 && [ "$SCANLEVEL" != force ] && {
+					[ "$SCANLEVEL" = quick ] && return
+					break
+				}
 			done
 		done
 		for s in  '--methodspace' '--unixeol' '--methodeol'; do
@@ -1355,31 +1404,22 @@ tpws_check_domain_http_bypass_()
 	else
 		for mss in '' 88; do
 			s3=${mss:+--mss=$mss}
-			for s2 in '' '--oob' '--disorder' '--oob --disorder'; do
+			for s2 in '' '--oob' '--disorder' ${oobdis:+"$oobdis"}; do
-				for pos in sni sniext; do
+				for pos in $splits_tls; do
-					s="--split-tls=$pos"
+					tpws_curl_test_update $1 $3 --split-pos=$pos $s2 $s3 && warn_mss $s3 && [ "$SCANLEVEL" != force ] && {
-					tpws_curl_test_update $1 $3 $s $s2 $s3 && warn_mss $s3 && [ "$SCANLEVEL" != force ] && {
-						[ "$SCANLEVEL" = quick ] && return
-						break
-					}
-				done
-				for pos in 1 2 3 4 5 10 50; do
-					s="--split-pos=$pos"
-					tpws_curl_test_update $1 $3 $s $s2 $s3 && warn_mss $s3 && [ "$SCANLEVEL" != force ] && {
 						[ "$SCANLEVEL" = quick ] && return
 						break
 					}
 				done
 			done
-			for s2 in '--tlsrec=sni' '--tlsrec=sni --split-tls=sni' '--tlsrec=sni --split-tls=sni --oob' \
+			for s in '' '--oob' '--disorder' ${oobdis:+"$oobdis"}; do
-					'--tlsrec=sni --split-tls=sni --disorder' '--tlsrec=sni --split-tls=sni --oob --disorder' \
+				for s2 in '--tlsrec=midsld' '--tlsrec=sniext+1 --split-pos=midsld' '--tlsrec=sniext+4 --split-pos=midsld' '--tlsrec=sniext+1 --split-pos=1,midsld' '--tlsrec=sniext+4 --split-pos=1,midsld' ; do
-					'--tlsrec=sni --split-pos=1' '--tlsrec=sni --split-pos=1 --oob' '--tlsrec=sni --split-pos=1 --disorder' \
+					tpws_curl_test_update $1 $3 $s2 $s $s3 && warn_mss $s3 && [ "$SCANLEVEL" != force ] && {
-					'--tlsrec=sni --split-pos=1 --oob --disorder'; do
-				tpws_curl_test_update $1 $3 $s2 $s3 && warn_mss $s3 && [ "$SCANLEVEL" != force ] && {
 						[ "$SCANLEVEL" = quick ] && return
 						break
 					}
 				done
+			done
 			# only linux supports mss
 			[ "$UNAME" = Linux -a "$sec" = 1 ] || break
 		done
@@ -1682,17 +1722,6 @@ ask_params()
 		echo "installed curl version does not support http3 QUIC. tests disabled."
 	fi
 
-	IGNORE_CA=0
-	CURL_OPT=
-	[ $ENABLE_HTTPS_TLS13 = 1 -o $ENABLE_HTTPS_TLS12 = 1 ] && {
-		echo
-		echo "on limited systems like openwrt CA certificates might not be installed to preserve space"
-		echo "in such a case curl cannot verify server certificate and you should either install ca-bundle or disable verification"
-		echo "however disabling verification will break https check if ISP does MitM attack and substitutes server certificate"
-		ask_yes_no_var IGNORE_CA "do not verify server certificate"
-		[ "$IGNORE_CA" = 1 ] && CURL_OPT=-k
-	}
-
 	echo
 	echo "sometimes ISPs use multiple DPIs or load balancing. bypass strategies may work unstable."
 	printf "how many times to repeat each test (default: 1) : "

common/base.sh

@@ -60,11 +60,22 @@ starts_with()
 	esac
 	return 1
 }
+extract_arg()
+{
+	# $1 - arg number
+	# $2,$3,... - args
+        local n=$1
+        while [ -n "$1" ]; do
+                shift
+                [ $n -eq 1 ] && { echo "$1"; return 0; }
+                n=$(($n-1))
+        done
+        return 1
+}
 find_str_in_list()
 {
 	# $1 - string
 	# $2 - space separated values
-
 	local v
 	[ -n "$1" ] && {
 		for v in $2; do

common/installer.sh

@@ -221,7 +221,7 @@ check_system()
 		else
 			echo system is not either systemd, openrc or openwrt based
 			echo easy installer can set up config settings but can\'t configure auto start
-			echo you have to do it manually. check readme.txt for manual setup info.
+			echo you have to do it manually. check readme.md for manual setup info.
 			if [ -n "$1" ] || ask_yes_no N "do you want to continue"; then
 			    SYSTEM=linux
 			else
@@ -232,7 +232,7 @@ check_system()
 	elif [ "$UNAME" = "Darwin" ]; then
 		SYSTEM=macos
 	else
-		echo easy installer only supports Linux and MacOS. check readme.txt for supported systems and manual setup info.
+		echo easy installer only supports Linux and MacOS. check readme.md for supported systems and manual setup info.
 		exitp 5
 	fi
 	echo system is based on $SYSTEM

nfq/darkmagic.c

@@ -163,7 +163,7 @@ static void fill_udphdr(struct udphdr *udp, uint16_t nsport, uint16_t ndport, ui
 	udp->uh_sum = 0;
 }
 
-static void fill_iphdr(struct ip *ip, const struct in_addr *src, const struct in_addr *dst, uint16_t pktlen, uint8_t proto, uint8_t ttl, uint8_t tos)
+static void fill_iphdr(struct ip *ip, const struct in_addr *src, const struct in_addr *dst, uint16_t pktlen, uint8_t proto, uint8_t ttl, uint8_t tos, uint16_t ip_id)
 {
 	ip->ip_tos = tos;
 	ip->ip_sum = 0;
@@ -171,7 +171,7 @@ static void fill_iphdr(struct ip *ip, const struct in_addr *src, const struct in
 	ip->ip_v = 4;
 	ip->ip_hl = 5;
 	ip->ip_len = htons(pktlen);
-	ip->ip_id = 0;
+	ip->ip_id = ip_id;
 	ip->ip_ttl = ttl;
 	ip->ip_p = proto;
 	ip->ip_src = *src;
@@ -196,6 +196,7 @@ bool prepare_tcp_segment4(
 	uint32_t *timestamps,
 	uint8_t ttl,
 	uint8_t tos,
+	uint16_t ip_id,
 	uint32_t fooling,
 	uint32_t badseq_increment,
 	uint32_t badseq_ack_increment,
@@ -211,7 +212,7 @@ bool prepare_tcp_segment4(
 	struct tcphdr *tcp = (struct tcphdr*)(ip+1);
 	uint8_t *payload = (uint8_t*)(tcp+1)+tcpoptlen;
 
-	fill_iphdr(ip, &src->sin_addr, &dst->sin_addr, pktlen, IPPROTO_TCP, ttl, tos);
+	fill_iphdr(ip, &src->sin_addr, &dst->sin_addr, pktlen, IPPROTO_TCP, ttl, tos, ip_id);
 	fill_tcphdr(tcp,fooling,tcp_flags,nseq,nack_seq,src->sin_port,dst->sin_port,nwsize,scale_factor,timestamps,badseq_increment,badseq_ack_increment,len);
 
 	memcpy(payload,data,len);
@@ -314,7 +315,9 @@ bool prepare_tcp_segment(
 	uint8_t scale_factor,
 	uint32_t *timestamps,
 	uint8_t ttl,
-	uint8_t tos, uint32_t flow_label,
+	uint8_t tos,
+	uint16_t ip_id,
+	uint32_t flow_label,
 	uint32_t fooling,
 	uint32_t badseq_increment,
 	uint32_t badseq_ack_increment,
@@ -322,7 +325,7 @@ bool prepare_tcp_segment(
 	uint8_t *buf, size_t *buflen)
 {
 	return (src->sa_family==AF_INET && dst->sa_family==AF_INET) ?
-		prepare_tcp_segment4((struct sockaddr_in *)src,(struct sockaddr_in *)dst,tcp_flags,nseq,nack_seq,nwsize,scale_factor,timestamps,ttl,tos,fooling,badseq_increment,badseq_ack_increment,data,len,buf,buflen) :
+		prepare_tcp_segment4((struct sockaddr_in *)src,(struct sockaddr_in *)dst,tcp_flags,nseq,nack_seq,nwsize,scale_factor,timestamps,ttl,tos,ip_id,fooling,badseq_increment,badseq_ack_increment,data,len,buf,buflen) :
 		(src->sa_family==AF_INET6 && dst->sa_family==AF_INET6) ?
 		prepare_tcp_segment6((struct sockaddr_in6 *)src,(struct sockaddr_in6 *)dst,tcp_flags,nseq,nack_seq,nwsize,scale_factor,timestamps,ttl,flow_label,fooling,badseq_increment,badseq_ack_increment,data,len,buf,buflen) :
 		false;
@@ -334,6 +337,7 @@ bool prepare_udp_segment4(
 	const struct sockaddr_in *src, const struct sockaddr_in *dst,
 	uint8_t ttl,
 	uint8_t tos,
+	uint16_t ip_id,
 	uint32_t fooling,
 	const uint8_t *padding, size_t padding_size,
 	int padlen,
@@ -357,7 +361,7 @@ bool prepare_udp_segment4(
 	uint8_t *payload = (uint8_t*)(udp+1);
 
 
-	fill_iphdr(ip, &src->sin_addr, &dst->sin_addr, pktlen, IPPROTO_UDP, ttl, tos);
+	fill_iphdr(ip, &src->sin_addr, &dst->sin_addr, pktlen, IPPROTO_UDP, ttl, tos, ip_id);
 	fill_udphdr(udp, src->sin_port, dst->sin_port, datalen);
 
 	memcpy(payload,data,len);
@@ -463,7 +467,9 @@ bool prepare_udp_segment6(
 bool prepare_udp_segment(
 	const struct sockaddr *src, const struct sockaddr *dst,
 	uint8_t ttl,
-	uint8_t tos, uint32_t flow_label,
+	uint8_t tos,
+	uint16_t ip_id,
+	uint32_t flow_label,
 	uint32_t fooling,
 	const uint8_t *padding, size_t padding_size,
 	int padlen,
@@ -471,7 +477,7 @@ bool prepare_udp_segment(
 	uint8_t *buf, size_t *buflen)
 {
 	return (src->sa_family==AF_INET && dst->sa_family==AF_INET) ?
-		prepare_udp_segment4((struct sockaddr_in *)src,(struct sockaddr_in *)dst,ttl,tos,fooling,padding,padding_size,padlen,data,len,buf,buflen) :
+		prepare_udp_segment4((struct sockaddr_in *)src,(struct sockaddr_in *)dst,ttl,tos,ip_id,fooling,padding,padding_size,padlen,data,len,buf,buflen) :
 		(src->sa_family==AF_INET6 && dst->sa_family==AF_INET6) ?
 		prepare_udp_segment6((struct sockaddr_in6 *)src,(struct sockaddr_in6 *)dst,ttl,flow_label,fooling,padding,padding_size,padlen,data,len,buf,buflen) :
 		false;

nfq/darkmagic.h

@@ -61,6 +61,7 @@ uint32_t net16_add(uint16_t netorder_value, uint16_t cpuorder_increment);
 #define VERDICT_NOCSUM	4
 
 #define IP4_TOS(ip_header) (ip_header ? ip_header->ip_tos : 0)
+#define IP4_IP_ID(ip_header) (ip_header ? ip_header->ip_id : 0)
 #define IP6_FLOW(ip6_header) (ip6_header ? ip6_header->ip6_ctlun.ip6_un1.ip6_un1_flow : 0)
 
 // seq and wsize have network byte order
@@ -73,6 +74,7 @@ bool prepare_tcp_segment4(
 	uint32_t *timestamps,
 	uint8_t ttl,
 	uint8_t tos,
+	uint16_t ip_id,
 	uint32_t fooling,
 	uint32_t badseq_increment,
 	uint32_t badseq_ack_increment,
@@ -100,7 +102,9 @@ bool prepare_tcp_segment(
 	uint8_t scale_factor,
 	uint32_t *timestamps,
 	uint8_t ttl,
-	uint8_t tos, uint32_t flow_label,
+	uint8_t tos,
+	uint16_t ip_id,
+	uint32_t flow_label,
 	uint32_t fooling,
 	uint32_t badseq_increment,
 	uint32_t badseq_ack_increment,
@@ -112,6 +116,7 @@ bool prepare_udp_segment4(
 	const struct sockaddr_in *src, const struct sockaddr_in *dst,
 	uint8_t ttl,
 	uint8_t tos,
+	uint16_t ip_id,
 	uint32_t fooling,
 	const uint8_t *padding, size_t padding_size,
 	int padlen,
@@ -129,7 +134,9 @@ bool prepare_udp_segment6(
 bool prepare_udp_segment(
 	const struct sockaddr *src, const struct sockaddr *dst,
 	uint8_t ttl,
-	uint8_t tos, uint32_t flow_label,
+	uint8_t tos,
+	uint16_t ip_id,
+	uint32_t flow_label,
 	uint32_t fooling,
 	const uint8_t *padding, size_t padding_size,
 	int padlen,

nfq/desync.c

@@ -603,6 +603,22 @@ static void autottl_discover(t_ctrack *ctrack, bool bIpv6)
 	}
 }
 
+#ifdef BSD
+// BSD pass to divert socket ip_id=0 and does not auto set it if sent via divert socket
+static uint16_t IP4_IP_ID_FIX(const struct ip *ip)
+{
+	return ip ? ip->ip_id ? ip->ip_id : (uint16_t)random() : 0;
+}
+#define IP4_IP_ID_NEXT(ip_id) net16_add(ip_id,+1)
+#define IP4_IP_ID_PREV(ip_id) net16_add(ip_id,-1)
+#else
+// in linux kernel sets increasing ip_id if it's zero
+#define IP4_IP_ID_FIX(x) 0
+#define IP4_IP_ID_NEXT(ip_id) ip_id
+#define IP4_IP_ID_PREV(ip_id) ip_id
+#endif
+
+
 static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint32_t fwmark, const char *ifout, struct dissect *dis)
 {
 	uint8_t verdict=VERDICT_PASS;
@@ -787,7 +803,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 				case DESYNC_SYNACK:
 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, TH_SYN|TH_ACK, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-						ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+						ttl_fake,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 						dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 						NULL, 0, pkt1, &pkt1_len))
 					{
@@ -811,7 +827,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					}
 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-						ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+						ttl_orig,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 						0,0,0, dp->fake_syndata,dp->fake_syndata_size, pkt1,&pkt1_len))
 					{
 						return verdict;
@@ -844,6 +860,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 		size_t multisplit_pos[MAX_SPLITS];
 		int multisplit_count;
 		int i;
+		uint16_t ip_id;
 		t_l7proto l7proto = UNKNOWN;
 
 		if (replay)
@@ -1165,7 +1182,6 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						DLOG("all multisplit pos are outside of this packet\n");
 				}
 			}
-			seqovl_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, &dp->seqovl);
 		}
 		else if (dp->desync_mode==DESYNC_FAKEDSPLIT || dp->desync_mode==DESYNC_FAKEDDISORDER || dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_FAKEDDISORDER)
 		{
@@ -1187,15 +1203,26 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 				DLOG("normalized regular split pos : %zu\n",split_pos);
 			else
 				DLOG("regular split pos is outside of this packet\n");
-			seqovl_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, &dp->seqovl);
 		}
 		else
 		{
 			multisplit_count=0;
-			split_pos = seqovl_pos = 0;
+			split_pos = 0;
 		}
+		if (dp->desync_mode==DESYNC_FAKEDSPLIT || dp->desync_mode==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_MULTISPLIT)
+		{
+			// split seqovl only uses absolute positive values
+			seqovl_pos = (dp->seqovl.marker==PM_ABS && dp->seqovl.pos>0) ? dp->seqovl.pos : 0;
+			if (seqovl_pos)	DLOG("seqovl : %zu\n",seqovl_pos);
+		}
+		else if (dp->desync_mode==DESYNC_FAKEDDISORDER || dp->desync_mode==DESYNC_MULTIDISORDER || dp->desync_mode2==DESYNC_FAKEDDISORDER || dp->desync_mode2==DESYNC_MULTIDISORDER)
+		{
+			seqovl_pos = ResolvePos(rdata_payload, rlen_payload, l7proto, &dp->seqovl);
 			seqovl_pos = pos_normalize(seqovl_pos,reasm_offset,dis->len_payload);
-		if (seqovl_pos)	DLOG("normalized seqovl pos : %zu\n",seqovl_pos);
+			if (seqovl_pos)	DLOG("normalized seqovl : %zu\n",seqovl_pos);
+		}
+		else
+			seqovl_pos = 0;
 
 		// we do not need reasm buffer anymore
 		reasm_orig_cancel(ctrack);
@@ -1216,7 +1243,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 			case DESYNC_FAKE:
 				if (reasm_offset) break;
 				if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-					ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+					ttl_fake,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 					dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 					fake, fake_size, pkt1, &pkt1_len))
 				{
@@ -1230,7 +1257,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 			case DESYNC_RSTACK:
 				if (reasm_offset) break;
 				if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, TH_RST | (dp->desync_mode==DESYNC_RSTACK ? TH_ACK:0), dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-					ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+					ttl_fake,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 					dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 					NULL, 0, pkt1, &pkt1_len))
 				{
@@ -1248,7 +1275,7 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					(!multisplit_count && (dp->desync_mode2==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_MULTIDISORDER))))
 				{
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-						ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+						ttl_orig,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 						fooling_orig,0,0,
 						dis->data_payload, dis->len_payload, pkt1, &pkt1_len))
 					{
@@ -1280,6 +1307,9 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					uint8_t ovlseg[DPI_DESYNC_MAX_FAKE_LEN+100], *seg;
 					size_t seg_len,from,to;
 					unsigned int seqovl;
+
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+
 					for (i=0,from=0 ; i<=multisplit_count ; i++)
 					{
 						to = i==multisplit_count ? dis->len_payload : multisplit_pos[i];
@@ -1315,10 +1345,11 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 							pkt1_len = sizeof(pkt1);
 							if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig,
 									net32_add(dis->tcp->th_seq,from-seqovl), dis->tcp->th_ack,
-									dis->tcp->th_win, scale_factor, timestamps,ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+									dis->tcp->th_win, scale_factor, timestamps,ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 									fooling_orig,0,0,
 									seg, seg_len, pkt1, &pkt1_len))
 								return verdict;
+							ip_id=IP4_IP_ID_NEXT(ip_id);
 							DLOG("sending multisplit part %d %zu-%zu len=%zu seqovl=%u : ",i+1,from,to-1,to-from,seqovl);
 							hexdump_limited_dlog(seg,seg_len,PKTDATA_MAXDUMP); DLOG("\n");
 							if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
@@ -1348,6 +1379,9 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					uint8_t ovlseg[DPI_DESYNC_MAX_FAKE_LEN+100], *seg;
 					size_t seg_len,from,to;
 					unsigned int seqovl;
+
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+
 					for (i=multisplit_count-1,to=dis->len_payload ; i>=-1 ; i--)
 					{
 						from = i>=0 ? multisplit_pos[i] : 0;
@@ -1380,10 +1414,11 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						pkt1_len = sizeof(pkt1);
 						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig,
 								net32_add(dis->tcp->th_seq,from-seqovl), dis->tcp->th_ack,
-								dis->tcp->th_win, scale_factor, timestamps,ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+								dis->tcp->th_win, scale_factor, timestamps,ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 								fooling_orig,0,0,
 								seg, seg_len, pkt1, &pkt1_len))
 							return verdict;
+						ip_id=IP4_IP_ID_PREV(ip_id);
 						DLOG("sending multisplit part %d %zu-%zu len=%zu seqovl=%u : ",i+2,from,to-1,to-from,seqovl);
 						hexdump_limited_dlog(seg,seg_len,PKTDATA_MAXDUMP); DLOG("\n");
 						if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
@@ -1401,6 +1436,8 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					size_t seg_len;
 					unsigned int seqovl;
 
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+
 					if (seqovl_pos>=split_pos)
 					{
 						DLOG("seqovl>=split_pos (%u>=%zu). cancelling seqovl.\n",seqovl_pos,split_pos);
@@ -1409,8 +1446,6 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					else
 						seqovl = seqovl_pos;
 
-					if (split_pos<dis->len_payload)
-					{
 					if (seqovl)
 					{
 						seg_len = dis->len_payload-split_pos+seqovl;
@@ -1428,25 +1463,25 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						seg = dis->data_payload+split_pos;
 						seg_len = dis->len_payload-split_pos;
 					}
-
 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(dis->tcp->th_seq , split_pos - seqovl), dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-								ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 							fooling_orig,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 							seg, seg_len, pkt1, &pkt1_len))
 						return verdict;
+					ip_id=IP4_IP_ID_PREV(ip_id);
 					DLOG("sending 2nd out-of-order tcp segment %zu-%zu len=%zu seqovl=%u : ",split_pos,dis->len_payload-1, dis->len_payload-split_pos, seqovl);
 					hexdump_limited_dlog(seg,seg_len,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 						return verdict;
-					}
 
 					seg_len = sizeof(fakeseg);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-							ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							ttl_fake,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 							dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 							zeropkt, split_pos, fakeseg, &seg_len))
 						return verdict;
+					ip_id=IP4_IP_ID_PREV(ip_id);
 					DLOG("sending fake(1) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
 					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
@@ -1454,15 +1489,17 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 
 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-							ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 							fooling_orig,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 							dis->data_payload, split_pos, pkt1, &pkt1_len))
 						return verdict;
+					ip_id=IP4_IP_ID_PREV(ip_id);
 					DLOG("sending 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
 					hexdump_limited_dlog(dis->data_payload,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 						return verdict;
 
+					if (dis->ip) ((struct ip*)fakeseg)->ip_id = ip_id;
 					DLOG("sending fake(2) 1st out-of-order tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
 					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, seg_len))
@@ -1477,12 +1514,15 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					uint8_t fakeseg[DPI_DESYNC_MAX_FAKE_LEN+100],ovlseg[DPI_DESYNC_MAX_FAKE_LEN+100], *seg;
 					size_t fakeseg_len,seg_len;
 
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+
 					fakeseg_len = sizeof(fakeseg);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, dis->tcp->th_seq, dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-							ttl_fake,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							ttl_fake,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 							dp->desync_fooling_mode,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 							zeropkt, split_pos, fakeseg, &fakeseg_len))
 						return verdict;
+					ip_id=IP4_IP_ID_NEXT(ip_id);
 					DLOG("sending fake(1) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
 					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
@@ -1514,10 +1554,11 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 
 						pkt1_len = sizeof(pkt1);
 						if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(dis->tcp->th_seq,-seqovl), dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-								ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+								ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 								fooling_orig,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 								seg, seg_len, pkt1, &pkt1_len))
 							return verdict;
+						ip_id=IP4_IP_ID_NEXT(ip_id);
 						DLOG("sending 1st tcp segment 0-%zu len=%zu seqovl=%u : ",split_pos-1, split_pos, seqovl);
 						hexdump_limited_dlog(seg,seg_len,PKTDATA_MAXDUMP); DLOG("\n");
 						if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
@@ -1535,17 +1576,16 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 						break;
 					}
 #endif
-
+					if (dis->ip) ((struct ip*)fakeseg)->ip_id = ip_id;
+					ip_id=IP4_IP_ID_NEXT(ip_id);
 					DLOG("sending fake(2) 1st tcp segment 0-%zu len=%zu : ",split_pos-1, split_pos);
 					hexdump_limited_dlog(zeropkt,split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend_rep(dp->desync_repeats,(struct sockaddr *)&dst, desync_fwmark, ifout , fakeseg, fakeseg_len))
 						return verdict;
 
-					if (split_pos<dis->len_payload)
-					{
 					pkt1_len = sizeof(pkt1);
 					if (!prepare_tcp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, flags_orig, net32_add(dis->tcp->th_seq,split_pos), dis->tcp->th_ack, dis->tcp->th_win, scale_factor, timestamps,
-								ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+							ttl_orig,IP4_TOS(dis->ip),ip_id,IP6_FLOW(dis->ip6),
 							fooling_orig,dp->desync_badseq_increment,dp->desync_badseq_ack_increment,
 							dis->data_payload+split_pos, dis->len_payload-split_pos, pkt1, &pkt1_len))
 						return verdict;
@@ -1553,7 +1593,6 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					hexdump_limited_dlog(dis->data_payload+split_pos,dis->len_payload-split_pos,PKTDATA_MAXDUMP); DLOG("\n");
 					if (!rawsend((struct sockaddr *)&dst, desync_fwmark, ifout , pkt1, pkt1_len))
 						return verdict;
-					}
 
 					return VERDICT_DROP;
 				}
@@ -1566,8 +1605,9 @@ static uint8_t dpi_desync_tcp_packet_play(bool replay, size_t reasm_offset, uint
 					uint8_t pkt3[DPI_DESYNC_MAX_FAKE_LEN+100], *pkt_orig;
 					size_t pkt_orig_len;
 
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+					uint32_t ident = dis->ip ? ip_id ? ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
 					size_t ipfrag_pos = (dp->desync_ipfrag_pos_tcp && dp->desync_ipfrag_pos_tcp<dis->transport_len) ? dp->desync_ipfrag_pos_tcp : 24;
-					uint32_t ident = dis->ip ? dis->ip->ip_id ? dis->ip->ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
 
 					pkt1_len = sizeof(pkt1);
 					pkt2_len = sizeof(pkt2);
@@ -1735,6 +1775,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 		size_t fake_size;
 		char host[256];
 		bool bHaveHost=false;
+		uint16_t ip_id;
 
 		if (IsQUICInitial(dis->data_payload,dis->len_payload))
 		{
@@ -2005,7 +2046,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					break;
 				}
 			case DESYNC_FAKE:
-				if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_fake, IP4_TOS(dis->ip),IP6_FLOW(dis->ip6), dp->desync_fooling_mode, NULL, 0, 0, fake, fake_size, pkt1, &pkt1_len))
+				if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_fake, IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6), dp->desync_fooling_mode, NULL, 0, 0, fake, fake_size, pkt1, &pkt1_len))
 					return verdict;
 				DLOG("sending fake : ");
 				hexdump_limited_dlog(fake,fake_size,PKTDATA_MAXDUMP); DLOG("\n");
@@ -2020,7 +2061,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 				if (dis->ip6 && (dp->desync_mode2==DESYNC_NONE || !desync_valid_second_stage_udp(dp->desync_mode2)))
 				{
 					if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst,
-						ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6),
+						ttl_orig,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6),
 						fooling_orig,NULL,0,0,
 						dis->data_payload, dis->len_payload, pkt1, &pkt1_len))
 					{
@@ -2043,7 +2084,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 		{
 			case DESYNC_UDPLEN:
 				pkt1_len = sizeof(pkt1);
-				if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, dp->udplen_pattern, sizeof(dp->udplen_pattern), dp->udplen_increment, dis->data_payload, dis->len_payload, pkt1, &pkt1_len))
+				if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, dp->udplen_pattern, sizeof(dp->udplen_pattern), dp->udplen_increment, dis->data_payload, dis->len_payload, pkt1, &pkt1_len))
 				{
 					DLOG("could not construct packet with modified length. too large ?\n");
 					break;
@@ -2068,7 +2109,7 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					memcpy(pkt2+pkt2_len,dis->data_payload+1,szcopy);
 					pkt2_len+=szcopy;
 					pkt1_len = sizeof(pkt1);
-					if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, NULL, 0 , 0, pkt2, pkt2_len, pkt1, &pkt1_len))
+					if (!prepare_udp_segment((struct sockaddr *)&src, (struct sockaddr *)&dst, ttl_orig,IP4_TOS(dis->ip),IP4_IP_ID_FIX(dis->ip),IP6_FLOW(dis->ip6), fooling_orig, NULL, 0 , 0, pkt2, pkt2_len, pkt1, &pkt1_len))
 					{
 						DLOG("could not construct packet with modified length. too large ?\n");
 						break;
@@ -2090,9 +2131,10 @@ static uint8_t dpi_desync_udp_packet_play(bool replay, size_t reasm_offset, uint
 					uint8_t pkt3[DPI_DESYNC_MAX_FAKE_LEN+100], *pkt_orig;
 					size_t pkt_orig_len;
 					
-					size_t ipfrag_pos = (dp->desync_ipfrag_pos_udp && dp->desync_ipfrag_pos_udp<dis->transport_len) ? dp->desync_ipfrag_pos_udp : sizeof(struct udphdr);
 					// freebsd do not set ip.id
-					uint32_t ident = dis->ip ? dis->ip->ip_id ? dis->ip->ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
+					ip_id = IP4_IP_ID_FIX(dis->ip);
+					uint32_t ident = dis->ip ? ip_id ? ip_id : htons(1+random()%0xFFFF) : htonl(1+random()%0xFFFFFFFF);
+					size_t ipfrag_pos = (dp->desync_ipfrag_pos_udp && dp->desync_ipfrag_pos_udp<dis->transport_len) ? dp->desync_ipfrag_pos_udp : sizeof(struct udphdr);
 
 					pkt1_len = sizeof(pkt1);
 					pkt2_len = sizeof(pkt2);

nfq/nfqws.c

@@ -844,6 +844,11 @@ static void split_compat(struct desync_profile *dp)
 		dp->splits[dp->split_count].pos = 2;
 		dp->split_count++;
 	}
+	if ((dp->seqovl.marker!=PM_ABS || dp->seqovl.pos<0) && (dp->desync_mode==DESYNC_FAKEDSPLIT || dp->desync_mode==DESYNC_MULTISPLIT || dp->desync_mode2==DESYNC_FAKEDSPLIT || dp->desync_mode2==DESYNC_MULTISPLIT))
+	{
+		DLOG_ERR("split seqovl supports only absolute positive positions\n");
+		exit_clean(1);
+	}
 }
 
 static void SplitDebug(void)