static void
send_announcement(void *ptr)
{
struct xmac_hdr *hdr;
int announcement_len;
/* Set up the probe header. */
packetbuf_clear();
hdr = packetbuf_dataptr();
announcement_len = format_announcement((char *)hdr +
sizeof(struct xmac_hdr));
if(announcement_len > 0) {
packetbuf_set_datalen(sizeof(struct xmac_hdr) + announcement_len);
hdr->dispatch = DISPATCH;
hdr->type = TYPE_ANNOUNCEMENT;
packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &rimeaddr_node_addr);
packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &rimeaddr_null);
packetbuf_set_attr(PACKETBUF_ATTR_RADIO_TXPOWER, announcement_radio_txpower);
if(NETSTACK_FRAMER.create() >= 0) {
NETSTACK_RADIO.send(packetbuf_hdrptr(), packetbuf_totlen());
}
}
}
static void
send_announcement(void *ptr)
{
int announcement_len;
int transmit_len;
#if WITH_CONTIKIMAC_HEADER
struct hdr *chdr;
#endif /* WITH_CONTIKIMAC_HEADER */
/* Set up the probe header. */
packetbuf_clear();
announcement_len = format_announcement(packetbuf_dataptr());
if(announcement_len > 0) {
packetbuf_set_datalen(announcement_len);
packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &rimeaddr_node_addr);
packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &rimeaddr_null);
packetbuf_set_attr(PACKETBUF_ATTR_RADIO_TXPOWER,
announcement_radio_txpower);
#if WITH_CONTIKIMAC_HEADER
transmit_len = packetbuf_totlen();
if(packetbuf_hdralloc(sizeof(struct hdr)) == 0) {
/* Failed to allocate space for contikimac header */
PRINTF("contikimac: send announcement failed, too large header\n");
return;
}
chdr = packetbuf_hdrptr();
chdr->id = CONTIKIMAC_ID;
chdr->len = transmit_len;
#endif /* WITH_CONTIKIMAC_HEADER */
if(NETSTACK_FRAMER.create()) {
rtimer_clock_t t;
int i, collisions;
we_are_sending = 1;
/* Make sure that the packet is longer or equal to the shorest
packet length. */
transmit_len = packetbuf_totlen();
if(transmit_len < SHORTEST_PACKET_SIZE) {
#if 0
/* Pad with zeroes */
uint8_t *ptr;
ptr = packetbuf_dataptr();
memset(ptr + packetbuf_datalen(), 0, SHORTEST_PACKET_SIZE - transmit_len);
#endif
PRINTF("contikimac: shorter than shortest (%d)\n", packetbuf_totlen());
transmit_len = SHORTEST_PACKET_SIZE;
}
collisions = 0;
/* Check for collisions */
for(i = 0; i < CCA_COUNT_MAX; ++i) {
t = RTIMER_NOW();
on();
#if NURTIMER
while(RTIMER_CLOCK_LT(t, RTIMER_NOW(), t + CCA_CHECK_TIME));
#else
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + CCA_CHECK_TIME));
#endif
if(NETSTACK_RADIO.channel_clear() == 0) {
collisions++;
off();
break;
}
off();
#if NURTIMER
while(RTIMER_CLOCK_LT(t0, RTIMER_NOW(), t + CCA_SLEEP_TIME + CCA_CHECK_TIME));
#else
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + CCA_SLEEP_TIME + CCA_CHECK_TIME)) { }
#endif
}
if(collisions == 0) {
NETSTACK_RADIO.prepare(packetbuf_hdrptr(), transmit_len);
NETSTACK_RADIO.transmit(transmit_len);
t = RTIMER_NOW();
#if NURTIMER
while(RTIMER_CLOCK_LT(t, RTIMER_NOW(), t + INTER_PACKET_INTERVAL));
#else
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + INTER_PACKET_INTERVAL)) { }
#endif
NETSTACK_RADIO.transmit(transmit_len);
}
we_are_sending = 0;
}
}
}
