zapret-pcap.lua

lua/zapret-lib.lua

@@ -877,6 +877,20 @@ function genhost(len, template)
 	end
 end
 
+function is_absolute_path(path)
+	if string.sub(path,1,1)=='/' then return true end
+	local un = uname()
+	return string.sub(un.sysname,1,6)=="CYGWIN" and string.sub(path,2,2)==':'
+end
+function append_path(path,file)
+	return string.sub(path,#path,#path)=='/' and path..file or path.."/"..file
+end
+function writeable_file_name(filename)
+	if is_absolute_path(filename) then return filename end
+	local writedir = os.getenv("WRITEABLE")
+	if not writedir then return filename end
+	return append_path(writedir, filename)
+end
 
 -- arg : wsize=N . tcp window size
 -- arg : scale=N . tcp option scale factor

lua/zapret-pcap.lua

@@ -0,0 +1,22 @@
+-- test case : nfqws2 --qnum 200 --debug --lua-init=@zapret-lib.lua --lua-init=@zapret-pcap.lua:file=test.pcap --writeable=zdir
+-- arg : file=<filename> - file for storing pcap data. if --writeable is specified and filename is relative - append filename to writeable path
+function pcap(ctx, desync)
+	if not desync.arg.file or #desync.arg.file==0 then
+		error("pcap requires 'file' parameter")
+	end
+	local fn = writeable_file_name(desync.arg.file)
+	local f = io.open(fn, "a")
+	if not f then
+		error("pcap: could not write to '"..fn.."'")
+	end
+	local pos = f:seek()
+	if (pos==0) then
+		-- create pcap header
+		f:write("\xA1\xB2\x3C\x4D\x00\x02\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x65")
+	end
+	local raw = raw_packet(ctx)
+	local sec, nsec = clock_gettime();
+	f:write(bu32(sec)..bu32(nsec)..bu32(#raw)..bu32(#raw))
+	f:write(raw)
+	f:close()
+end