Avoid using memcpy on unaligned uint16_t variables, because certain compilers will optimize this code to a direct copy instruction that will result in unaligned memory access. Thanks to Angelo Compagnucci for reporting this problem.

core/net/rime/broadcast-announcement.c

@@ -56,7 +56,6 @@
 #endif
 
 #include <string.h>
-#include <stdio.h>
 #include <stddef.h>
 
 struct announcement_data {
@@ -131,32 +130,31 @@ static void
 adv_packet_received(struct broadcast_conn *ibc, const rimeaddr_t *from)
 {
   struct announcement_msg adata;
+  struct announcement_data data;
+  uint8_t *ptr;
   int i;
 
+  ptr = packetbuf_dataptr();
+
   /* Copy number of announcements */
-  memcpy(&adata, packetbuf_dataptr(), sizeof(struct announcement_msg));
+  memcpy(&adata, ptr, sizeof(struct announcement_msg));
   PRINTF("%d.%d: adv_packet_received from %d.%d with %d announcements\n",
 	 rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
 	 from->u8[0], from->u8[1], adata.num);
 
-  if(adata.num / sizeof(struct announcement_data) > sizeof(struct announcement_msg)) {
+  if(ANNOUNCEMENT_MSG_HEADERLEN + adata.num * sizeof(struct announcement_data) > packetbuf_datalen()) {
     /* The number of announcements is too large - corrupt packet has
        been received. */
-    printf("adata.num way out there: %d\n", adata.num);
+    PRINTF("adata.num way out there: %d\n", adata.num);
     return;
   }
 
+  ptr += ANNOUNCEMENT_MSG_HEADERLEN;
   for(i = 0; i < adata.num; ++i) {
-    struct announcement_data data;
-
     /* Copy announcements */
-    memcpy(&data.id, &((struct announcement_msg *)packetbuf_dataptr())->data[i].id,
-          sizeof(uint16_t));
-    memcpy(&data.value, &((struct announcement_msg *)packetbuf_dataptr())->data[i].value,
-          sizeof(uint16_t));
-    announcement_heard(from,
-		       data.id,
-		       data.value);
+    memcpy(&data, ptr, sizeof(struct announcement_data));
+    announcement_heard(from, data.id, data.value);
+    ptr += sizeof(struct announcement_data);
   }
 }
 /*---------------------------------------------------------------------------*/

core/net/rime/collect.c

@@ -758,8 +758,7 @@ send_next_packet(struct collect_conn *tc)
 static void
 handle_ack(struct collect_conn *tc)
 {
-  struct ack_msg *msg;
-  uint16_t rtmetric;
+  struct ack_msg msg;
   struct collect_neighbor *n;
 
   PRINTF("handle_ack: sender %d.%d current_parent %d.%d, id %d seqno %d\n",
@@ -778,8 +777,7 @@ handle_ack(struct collect_conn *tc)
            (int)(((100 * (clock_time() - tc->send_time)) / CLOCK_SECOND) % 100));*/
     
     stats.ackrecv++;
-    msg = packetbuf_dataptr();
-    memcpy(&rtmetric, &msg->rtmetric, sizeof(uint16_t));
+    memcpy(&msg, packetbuf_dataptr(), sizeof(struct ack_msg));
 
     /* It is possible that we receive an ACK for a packet that we
        think we have not yet sent: if our transmission was received by
@@ -797,7 +795,7 @@ handle_ack(struct collect_conn *tc)
 
     if(n != NULL) {
       collect_neighbor_tx(n, tc->transmissions);
-      collect_neighbor_update_rtmetric(n, rtmetric);
+      collect_neighbor_update_rtmetric(n, msg.rtmetric);
       update_rtmetric(tc);
     }
 
@@ -805,8 +803,8 @@ handle_ack(struct collect_conn *tc)
            rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
            tc->current_parent.u8[0], tc->current_parent.u8[1],
            tc->transmissions,
-           msg->flags,
-           rtmetric);
+           msg.flags,
+           msg.rtmetric);
 
     /* The ack contains information about the state of the packet and
        of the node that received it. We do different things depending
@@ -814,20 +812,20 @@ handle_ack(struct collect_conn *tc)
        the receiving node was congested. If so, we add a maximum
        transmission number to its routing metric, which increases the
        chance that another parent will be chosen. */
-    if(msg->flags & ACK_FLAGS_CONGESTED) {
+    if(msg.flags & ACK_FLAGS_CONGESTED) {
       PRINTF("ACK flag indicated parent was congested.\n");
       collect_neighbor_set_congested(n);
       collect_neighbor_tx(n, tc->max_rexmits * 2);
       update_rtmetric(tc);
     }
-    if((msg->flags & ACK_FLAGS_DROPPED) == 0) {
+    if((msg.flags & ACK_FLAGS_DROPPED) == 0) {
       /* If the packet was successfully received, we send the next packet. */
       send_next_packet(tc);
     } else {
       /* If the packet was lost due to its lifetime being exceeded,
          there is not much more we can do with the packet, so we send
          the next one instead. */
-      if((msg->flags & ACK_FLAGS_LIFETIME_EXCEEDED)) {
+      if((msg.flags & ACK_FLAGS_LIFETIME_EXCEEDED)) {
         send_next_packet(tc);
       } else {
         /* If the packet was dropped, but without the node being
@@ -845,7 +843,7 @@ handle_ack(struct collect_conn *tc)
 
     /* Our neighbor's rtmetric needs to be updated, so we bump our
        advertisements. */
-    if(msg->flags & ACK_FLAGS_RTMETRIC_NEEDS_UPDATE) {
+    if(msg.flags & ACK_FLAGS_RTMETRIC_NEEDS_UPDATE) {
       bump_advertisement(tc);
     }
     set_keepalive_timer(tc);

core/net/rime/neighbor-discovery.c

@@ -96,23 +96,22 @@ static void
 adv_packet_received(struct broadcast_conn *ibc, const rimeaddr_t *from)
 {
   struct neighbor_discovery_conn *c = (struct neighbor_discovery_conn *)ibc;
-  struct adv_msg *msg = packetbuf_dataptr();
-  uint16_t val;
+  struct adv_msg msg;
 
-  memcpy(&val, &msg->val, sizeof(val));
+  memcpy(&msg, packetbuf_dataptr(), sizeof(struct adv_msg));
 
   PRINTF("%d.%d: adv_packet_received from %d.%d with val %d\n",
 	 rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
-	 from->u8[0], from->u8[1], val);
+	 from->u8[0], from->u8[1], msg.val);
   
   /* If we receive an announcement with a lower value than ours, we
      cancel our own announcement. */
-  if(val < c->val) {
+  if(msg.val < c->val) {
     /*    ctimer_stop(&c->send_timer);*/
   }
 
   if(c->u->recv) {
-    c->u->recv(c, from, val);
+    c->u->recv(c, from, msg.val);
   }
 }
 /*---------------------------------------------------------------------------*/

core/net/rime/polite-announcement.c

@@ -125,25 +125,31 @@ static void
 adv_packet_received(struct ipolite_conn *ipolite, const rimeaddr_t *from)
 {
   struct announcement_msg adata;
+  struct announcement_data data;
+  uint8_t *ptr;
   int i;
 
+  ptr = packetbuf_dataptr();
+
   /* Copy number of announcements */
-  memcpy(&adata, packetbuf_dataptr(), sizeof(struct announcement_msg));
+  memcpy(&adata, ptr, sizeof(struct announcement_msg));
   PRINTF("%d.%d: adv_packet_received from %d.%d with %d announcements\n",
 	 rimeaddr_node_addr.u8[0], rimeaddr_node_addr.u8[1],
 	 from->u8[0], from->u8[1], adata.num);
 
-  for(i = 0; i < adata.num; ++i) {
-    struct announcement_data data;
+  if(ANNOUNCEMENT_MSG_HEADERLEN + adata.num * sizeof(struct announcement_data) > packetbuf_datalen()) {
+    /* The number of announcements is too large - corrupt packet has
+       been received. */
+    PRINTF("adata.num way out there: %d\n", adata.num);
+    return;
+  }
 
+  ptr += ANNOUNCEMENT_MSG_HEADERLEN;
+  for(i = 0; i < adata.num; ++i) {
     /* Copy announcements */
-    memcpy(&data.id, &((struct announcement_msg *)packetbuf_dataptr())->data[i].id,
-          sizeof(uint16_t));
-    memcpy(&data.value, &((struct announcement_msg *)packetbuf_dataptr())->data[i].value,
-          sizeof(uint16_t));
-    announcement_heard(from,
-		       data.id,
-		       data.value);
+    memcpy(&data, ptr, sizeof(struct announcement_data));
+    announcement_heard(from, data.id, data.value);
+    ptr += sizeof(struct announcement_data);
   }
 }
 /*---------------------------------------------------------------------------*/