dtls: use dynamic sizes for netq when possible

When each package stored in netq is dynamically allocated we should not make space for DTLS_MAX_BUF, but allocate as many bytes as needed for this specific packet. This reduces the space needed for the retransmission queue by ~50% on a Linux system. Signed-off-by: Hauke Mehrtens <[email protected]>
particle-iot · Dec 19, 2013 · f9ca99d · f9ca99d
1 parent c0ed926
commit f9ca99d
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Showing 3 changed files with 12 additions and 8 deletions.
diff --git a/dtls.c b/dtls.c
@@ -1372,7 +1372,7 @@ dtls_send_multi(dtls_context_t *ctx, dtls_peer_t *peer,
   if ((type == DTLS_CT_HANDSHAKE && buf_array[0][0] != DTLS_HT_HELLO_VERIFY_REQUEST) ||
       type == DTLS_CT_CHANGE_CIPHER_SPEC) {
     /* copy handshake messages other than HelloVerify into retransmit buffer */
-    netq_t *n = netq_node_new();
+    netq_t *n = netq_node_new(overall_len);
     if (n) {
       dtls_tick_t now;
       dtls_ticks(&now);
@@ -3327,7 +3327,7 @@ handle_handshake(dtls_context_t *ctx, dtls_peer_t *peer, session_t *session,
       node = netq_next(node);
     }
 
-    n = netq_node_new();
+    n = netq_node_new(data_length);
     if (!n) {
       dtls_warn("no space in reoder buffer\n");
       return 0;

diff --git a/netq.c b/netq.c
@@ -24,8 +24,8 @@
 #include <stdlib.h>
 
 static inline netq_t *
-netq_malloc_node() {
-  return (netq_t *)malloc(sizeof(netq_t));
+netq_malloc_node(size_t size) {
+  return (netq_t *)malloc(sizeof(netq_t) + size);
 }
 
 static inline void
@@ -41,7 +41,7 @@ netq_free_node(netq_t *node) {
 MEMB(netq_storage, netq_t, NETQ_MAXCNT);
 
 static inline netq_t *
-netq_malloc_node() {
+netq_malloc_node(size_t size) {
   return (netq_t *)memb_alloc(&netq_storage);
 }
 
@@ -107,9 +107,9 @@ netq_t *netq_pop_first(list_t queue) {
 }
 
 netq_t *
-netq_node_new() {
+netq_node_new(size_t size) {
   netq_t *node;
-  node = netq_malloc_node();
+  node = netq_malloc_node(size);
 
 #ifndef NDEBUG
   if (!node)

diff --git a/netq.h b/netq.h
@@ -47,7 +47,11 @@ typedef struct netq_t {
   unsigned char retransmit_cnt;	/**< retransmission counter, will be removed when zero */
 
   size_t length;		/**< actual length of data */
+#ifndef WITH_CONTIKI
+  unsigned char data[];		/**< the datagram to send */
+#else
   netq_packet_t data;		/**< the datagram to send */
+#endif
 } netq_t;
 
 #ifndef WITH_CONTIKI
@@ -76,7 +80,7 @@ void netq_node_free(netq_t *node);
 void netq_delete_all(list_t queue);
 
 /** Creates a new node suitable for adding to a netq_t queue. */
-netq_t *netq_node_new();
+netq_t *netq_node_new(size_t size);
 
 /**
  * Returns a pointer to the first item in given queue or NULL if