split PACKET's transform field to give way for seperate compression field

include/n2n_define.h

@@ -58,18 +58,13 @@
 /* Compression is disabled by default for outgoing packets if no cli
  * option is given. All edges are built with decompression support so
  * they are able to understand each other (this applies to lzo only). */
-#define N2N_COMPRESSION_ID_NONE		0	/* default, see edge_init_conf_defaults(...) in edge_utils.c */
+#define N2N_COMPRESSION_ID_INVALID	0
-#define N2N_COMPRESSION_ID_LZO		1	/* set if '-z1' or '-z' cli option is present, see setOption(...) in edge.c */
+#define N2N_COMPRESSION_ID_NONE		1	/* default, see edge_init_conf_defaults(...) in edge_utils.c */
+#define N2N_COMPRESSION_ID_LZO		2	/* set if '-z1' or '-z' cli option is present, see setOption(...) in edge.c */
 #ifdef N2N_HAVE_ZSTD
-#define N2N_COMPRESSION_ID_ZSTD		2	/* set if '-z2' cli option is present, available only if compiled with zstd lib */
+#define N2N_COMPRESSION_ID_ZSTD		3	/* set if '-z2' cli option is present, available only if compiled with zstd lib */
 #define ZSTD_COMPRESSION_LEVEL		7	/* 1 (faster) ... 22 (more compression) */
 #endif
-// with the next major packet structure update, make '0' = invalid, and '1' = no compression
-// '2' = LZO, '3' = ZSTD, ... REVISIT then (also: change all occurences in source).
-
-#define N2N_COMPRESSION_ID_BITLEN	3	/* number of bits used for encoding compression id in the uppermost
-				 	           bits of transform_id; will be obsolete as soon as compression gets
-						   its own field in the packet. REVISIT then. */
 
 /* (un)purgeable community indicator (supernode) */
 #define COMMUNITY_UNPURGEABLE		0

include/n2n_wire.h

@@ -140,8 +140,8 @@ typedef struct n2n_PACKET
     n2n_mac_t           srcMac;
     n2n_mac_t           dstMac;
     n2n_sock_t          sock;
-    uint16_t            transform;
+    uint8_t             transform;
-    uint16_t		compression;
+    uint8_t		compression;
 } n2n_PACKET_t;
 
 /* Linked with n2n_register_super in n2n_pc_t. Only from edge to supernode. */

src/edge.c

@@ -389,7 +389,7 @@ static int setOption(int optkey, char *optargument, n2n_tuntap_priv_config_t *ec
       if (optargument) {
         compression = atoi(optargument);
       } else
-	compression = N2N_COMPRESSION_ID_LZO; // default, if '-z' only
+	compression = 1; // default, if '-z' only, equals -z1
 
       setPayloadCompression(conf, compression);
       break;

src/edge_utils.c

@@ -1020,17 +1020,10 @@ static int handle_PACKET(n2n_edge_t * eee,
     uint8_t decodebuf[N2N_PKT_BUF_SIZE];
     size_t eth_size;
     n2n_transform_t rx_transop_id;
+    uint8_t rx_compression_id;
 
     rx_transop_id = (n2n_transform_t)pkt->transform;
-    /* optional compression is encoded in uppermost bit of transform field.
+    rx_compression_id = pkt->compression;
-     * this is an intermediate solution to maintain compatibility until some
-     * upcoming major release (3.0?) brings up changes in packet structure anyway
-     * in the course of which a dedicated compression field could be spent.
-     * REVISIT then. */
-    uint16_t rx_compression_id;
-
-    rx_compression_id = (uint16_t)rx_transop_id >> (8*sizeof((uint16_t)rx_transop_id)-N2N_COMPRESSION_ID_BITLEN);
-    rx_transop_id &= (1 << (8*sizeof((uint16_t)rx_transop_id)-N2N_COMPRESSION_ID_BITLEN)) -1;
 
     if(rx_transop_id == eee->conf.transop_id) {
       uint8_t is_multicast;
@@ -1071,7 +1064,7 @@ static int handle_PACKET(n2n_edge_t * eee,
 	return (-1); // cannot handle it
       }
 
-      if(rx_compression_id) {
+      if(rx_compression_id != N2N_COMPRESSION_ID_NONE) {
 	traceEvent (TRACE_DEBUG, "payload decompression [%s]: deflated %u bytes to %u bytes",
 		    compression_str(rx_compression_id), eth_size, (int)deflated_len);
 	memcpy(eth_payload ,deflation_buffer, deflated_len );
@@ -1484,7 +1477,7 @@ void edge_send_packet2net(n2n_edge_t * eee,
       break;
     }
 
-    if(pkt.compression) {
+    if(pkt.compression != N2N_COMPRESSION_ID_NONE) {
       traceEvent (TRACE_DEBUG, "payload compression [%s]: compressed %u bytes to %u bytes\n",
 		  compression_str(pkt.compression), len, compression_len);
 
@@ -1493,12 +1486,6 @@ void edge_send_packet2net(n2n_edge_t * eee,
       free (compression_buffer);
     }
   }
-  /* optional compression is encoded in uppermost bits of transform field.
-   * this is an intermediate solution to maintain compatibility until some
-   * upcoming major release (3.0?) brings up changes in packet structure anyway
-   * in the course of which a dedicated compression field could be spent.
-   * REVISIT then. */
-  pkt.transform = pkt.transform | (pkt.compression << (8*sizeof(pkt.transform)-N2N_COMPRESSION_ID_BITLEN));
 
   idx=0;
   encode_PACKET(pktbuf, &idx, &cmn, &pkt);
@@ -2618,6 +2605,7 @@ int quick_edge_init(char *device_name, char *community_name,
   edge_init_conf_defaults(&conf);
   conf.encrypt_key = encrypt_key;
   conf.transop_id = N2N_TRANSFORM_ID_TWOFISH;
+  conf.compression = N2N_COMPRESSION_ID_NONE;
   snprintf((char*)conf.community_name, sizeof(conf.community_name), "%s", community_name);
   edge_conf_add_supernode(&conf, supernode_ip_address_port);
 

src/wire.c

@@ -453,7 +453,8 @@ int encode_PACKET( uint8_t * base,
     {
         retval += encode_sock( base, idx, &(pkt->sock) );
     }
-    retval += encode_uint16( base, idx, pkt->transform );
+    retval += encode_uint8( base, idx, pkt->compression );
+    retval += encode_uint8( base, idx, pkt->transform );
 
     return retval;
 }
@@ -475,7 +476,8 @@ int decode_PACKET( n2n_PACKET_t * pkt,
         retval += decode_sock( &(pkt->sock), base, rem, idx );
     }
 
-    retval += decode_uint16( &(pkt->transform), base, rem, idx );
+    retval += decode_uint8( &(pkt->compression), base, rem, idx );
+    retval += decode_uint8( &(pkt->transform), base, rem, idx );
 
     return retval;
 }