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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.

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This commit is contained in:
Niclas Finne 2012-03-31 01:25:27 +02:00
parent ed92994784
commit 2507ba4e8d
4 changed files with 42 additions and 41 deletions
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26
core/net/rime/broadcast-announcement.c
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@ -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;
}
for(i = 0; i < adata.num; ++i) {
struct announcement_data data;
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);
}
}
/*---------------------------------------------------------------------------*/