From 77c5187a2e1b6912af73436bedb356370255f654 Mon Sep 17 00:00:00 2001
From: joxe <joxe>
Date: Thu, 23 Sep 2010 19:57:50 +0000
Subject: [PATCH] fixed bug where context is null but still referenced

---
 core/net/sicslowpan.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/core/net/sicslowpan.c b/core/net/sicslowpan.c
index cf9daca04..12f26a91b 100644
--- a/core/net/sicslowpan.c
+++ b/core/net/sicslowpan.c
@@ -32,7 +32,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: sicslowpan.c,v 1.44 2010/06/06 12:44:12 joxe Exp $
+ * $Id: sicslowpan.c,v 1.45 2010/09/23 19:57:50 joxe Exp $
  */
 /**
  * \file
@@ -777,19 +777,17 @@ uncompress_hdr_hc06(u16_t ip_len) {
     uint8_t sci = (iphc1 & SICSLOWPAN_IPHC_CID) ?
       RIME_IPHC_BUF[2] >> 4 : 0;
 
-    /* Source address */
-    if((iphc1 & SICSLOWPAN_IPHC_SAM_11) != SICSLOWPAN_IPHC_SAM_00) {
-      context =
-	addr_context_lookup_by_number(sci);
+    /* Source address - check context != NULL only if SAM bits are != 0*/
+    if (tmp != 0) {
+      context = addr_context_lookup_by_number(sci);
       if(context == NULL) {
         PRINTF("sicslowpan uncompress_hdr: error context not found\n");
         return;
-      } else {
-        PRINTF("IPHC: found compressed source context for sci = %d\n", sci);
       }
     }
-    uncompress_addr(&SICSLOWPAN_IP_BUF->srcipaddr, context->prefix,
-                    unc_ctxconf[tmp],
+    /* if tmp == 0 we do not have a context and therefore no prefix */
+    uncompress_addr(&SICSLOWPAN_IP_BUF->srcipaddr,
+                    tmp != 0 ? context->prefix : NULL, unc_ctxconf[tmp],
                     (uip_lladdr_t *)packetbuf_addr(PACKETBUF_ADDR_SENDER));
   } else {
     /* no compression and link local */