zapret-auto: reset parameter to standard_detector

lua/zapret-auto.lua

@@ -135,6 +135,7 @@ end
 --   udp too much out with too few in
 -- arg: maxseq=<rseq> - tcp: test retransmissions only within this relative sequence. default is 32K
 -- arg: retrans=N - tcp: retrans count threshold. default is 3
+-- arg: reset - send RST to retransmitter to break long wait
 -- arg: inseq=<rseq> - tcp: maximum relative sequence number to treat incoming RST as DPI reset. default is 4K
 -- arg: no_http_redirect - tcp: disable http_reply dpi redirect trigger
 -- arg: no_rst - tcp: disable incoming RST trigger
@@ -151,6 +152,15 @@ function standard_failure_detector(desync, crec)
 					crec.retrans = crec.retrans and (crec.retrans+1) or 1
 					DLOG("standard_failure_detector: retransmission "..crec.retrans.."/"..arg.retrans)
 					trigger = crec.retrans>=arg.retrans
+					if trigger and desync.arg.reset then
+						local dis = deepcopy(desync.dis)
+						dis.payload = nil
+						dis_reverse(dis)
+						dis.tcp.th_flags = TH_RST
+						dis.tcp.th_win = desync.track and desync.track.pos.reverse.tcp.winsize or 64
+						DLOG("standard_failure_detector: sending RST to retransmitter")
+						rawsend_dissect(dis)
+					end
 				end
 			end
 		else

lua/zapret-lib.lua

@@ -762,6 +762,33 @@ function fix_ip6_next(ip6, last_proto)
 	end
 end
 
+-- reverses ip addresses, ports and seq/ack
+function dis_reverse(dis)
+	local temp
+	if dis.ip then
+		temp = dis.ip.ip_src
+		dis.ip.ip_src = dis.ip.ip_dst
+		dis.ip.ip_dst = temp
+	end
+	if dis.ip6 then
+		temp = dis.ip6.ip6_src
+		dis.ip6.ip6_src = dis.ip6.ip6_dst
+		dis.ip6.ip6_dst = temp
+	end
+	if dis.tcp then
+		temp = dis.tcp.th_sport
+		dis.tcp.th_sport = dis.tcp.th_dport
+		dis.tcp.th_dport = temp
+		temp = dis.tcp.th_ack
+		dis.tcp.th_ack = dis.tcp.th_seq
+		dis.tcp.th_seq = temp
+	end
+	if dis.udp then
+		temp = dis.udp.uh_sport
+		dis.udp.uh_sport = dis.udp.uh_dport
+		dis.udp.uh_dport = temp
+	end
+end
 
 -- parse autottl : delta,min-max
 function parse_autottl(s)