Defensive programming: make sure that we don't fail completely if we get a callback for a NULL pointer
This commit is contained in:
Adam Dunkels
parent
82b755c017
commit
f2fbb4b49d
@ -186,15 +186,19 @@ free_first_packet(struct neighbor_queue *n)
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static void
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packet_sent(void *ptr, int status, int num_transmissions)
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{
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struct neighbor_queue *n = ptr;
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struct rdc_buf_list *q = list_head(n->queued_packet_list);
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struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr;
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struct neighbor_queue *n;
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struct rdc_buf_list *q;
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struct qbuf_metadata *metadata;
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clock_time_t time = 0;
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mac_callback_t sent;
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void *cptr;
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int num_tx;
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int backoff_transmissions;
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n = ptr;
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if(n == NULL) {
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return;
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}
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switch(status) {
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case MAC_TX_OK:
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case MAC_TX_NOACK:
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@ -208,66 +212,72 @@ packet_sent(void *ptr, int status, int num_transmissions)
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break;
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}
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sent = metadata->sent;
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cptr = metadata->cptr;
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num_tx = n->transmissions;
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q = list_head(n->queued_packet_list);
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if(q != NULL) {
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metadata = (struct qbuf_metadata *)q->ptr;
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if(status == MAC_TX_COLLISION ||
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status == MAC_TX_NOACK) {
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if(metadata != NULL) {
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sent = metadata->sent;
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cptr = metadata->cptr;
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num_tx = n->transmissions;
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if(status == MAC_TX_COLLISION ||
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status == MAC_TX_NOACK) {
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/* If the transmission was not performed because of a collision or
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noack, we must retransmit the packet. */
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switch(status) {
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case MAC_TX_COLLISION:
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PRINTF("csma: rexmit collision %d\n", n->transmissions);
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break;
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case MAC_TX_NOACK:
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PRINTF("csma: rexmit noack %d\n", n->transmissions);
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break;
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default:
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PRINTF("csma: rexmit err %d, %d\n", status, n->transmissions);
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/* If the transmission was not performed because of a
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collision or noack, we must retransmit the packet. */
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switch(status) {
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case MAC_TX_COLLISION:
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PRINTF("csma: rexmit collision %d\n", n->transmissions);
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break;
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case MAC_TX_NOACK:
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PRINTF("csma: rexmit noack %d\n", n->transmissions);
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break;
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default:
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PRINTF("csma: rexmit err %d, %d\n", status, n->transmissions);
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}
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/* The retransmission time must be proportional to the channel
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check interval of the underlying radio duty cycling layer. */
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time = default_timebase();
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/* The retransmission time uses a linear backoff so that the
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interval between the transmissions increase with each
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retransmit. */
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backoff_transmissions = n->transmissions + 1;
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/* Clamp the number of backoffs so that we don't get a too long
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timeout here, since that will delay all packets in the
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queue. */
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if(backoff_transmissions > 3) {
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backoff_transmissions = 3;
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}
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time = time + (random_rand() % (backoff_transmissions * time));
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if(n->transmissions < metadata->max_transmissions) {
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PRINTF("csma: retransmitting with time %lu %p\n", time, q);
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ctimer_set(&n->transmit_timer, time,
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transmit_packet_list, n);
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/* This is needed to correctly attribute energy that we spent
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transmitting this packet. */
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queuebuf_update_attr_from_packetbuf(q->buf);
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} else {
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PRINTF("csma: drop with status %d after %d transmissions, %d collisions\n",
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status, n->transmissions, n->collisions);
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free_first_packet(n);
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mac_call_sent_callback(sent, cptr, status, num_tx);
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}
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} else {
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if(status == MAC_TX_OK) {
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PRINTF("csma: rexmit ok %d\n", n->transmissions);
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} else {
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PRINTF("csma: rexmit failed %d: %d\n", n->transmissions, status);
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}
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free_first_packet(n);
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mac_call_sent_callback(sent, cptr, status, num_tx);
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}
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}
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/* The retransmission time must be proportional to the channel
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check interval of the underlying radio duty cycling layer. */
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time = default_timebase();
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/* The retransmission time uses a linear backoff so that the
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interval between the transmissions increase with each
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retransmit. */
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backoff_transmissions = n->transmissions + 1;
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/* Clamp the number of backoffs so that we don't get a too long
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timeout here, since that will delay all packets in the
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queue. */
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if(backoff_transmissions > 3) {
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backoff_transmissions = 3;
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}
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time = time + (random_rand() % (backoff_transmissions * time));
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if(n->transmissions < metadata->max_transmissions) {
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PRINTF("csma: retransmitting with time %lu %p\n", time, q);
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ctimer_set(&n->transmit_timer, time,
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transmit_packet_list, n);
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/* This is needed to correctly attribute energy that we spent
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transmitting this packet. */
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queuebuf_update_attr_from_packetbuf(q->buf);
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} else {
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PRINTF("csma: drop with status %d after %d transmissions, %d collisions\n",
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status, n->transmissions, n->collisions);
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free_first_packet(n);
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mac_call_sent_callback(sent, cptr, status, num_tx);
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}
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} else {
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if(status == MAC_TX_OK) {
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PRINTF("csma: rexmit ok %d\n", n->transmissions);
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} else {
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PRINTF("csma: rexmit failed %d: %d\n", n->transmissions, status);
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}
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free_first_packet(n);
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mac_call_sent_callback(sent, cptr, status, num_tx);
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}
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}
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/*---------------------------------------------------------------------------*/
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@ -277,86 +287,77 @@ send_packet(mac_callback_t sent, void *ptr)
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struct rdc_buf_list *q;
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struct neighbor_queue *n;
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static uint16_t seqno;
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const rimeaddr_t *addr = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
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packetbuf_set_attr(PACKETBUF_ATTR_MAC_SEQNO, seqno++);
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/* If the packet is a broadcast, do not allocate a queue
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entry. Instead, just send it out. */
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if(!rimeaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_RECEIVER),
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&rimeaddr_null)) {
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const rimeaddr_t *addr = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
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/* Look for the neighbor entry */
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n = neighbor_queue_from_addr(addr);
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if(n == NULL) {
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/* Allocate a new neighbor entry */
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n = memb_alloc(&neighbor_memb);
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if(n != NULL) {
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/* Init neighbor entry */
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rimeaddr_copy(&n->addr, addr);
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n->transmissions = 0;
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n->collisions = 0;
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n->deferrals = 0;
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/* Init packet list for this neighbor */
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LIST_STRUCT_INIT(n, queued_packet_list);
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/* Add neighbor to the list */
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list_add(neighbor_list, n);
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}
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}
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/* Look for the neighbor entry */
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n = neighbor_queue_from_addr(addr);
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if(n == NULL) {
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/* Allocate a new neighbor entry */
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n = memb_alloc(&neighbor_memb);
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if(n != NULL) {
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/* Add packet to the neighbor's queue */
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q = memb_alloc(&packet_memb);
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if(q != NULL) {
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q->ptr = memb_alloc(&metadata_memb);
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if(q->ptr != NULL) {
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q->buf = queuebuf_new_from_packetbuf();
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if(q->buf != NULL) {
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struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr;
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/* Neighbor and packet successfully allocated */
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if(packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS) == 0) {
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/* Use default configuration for max transmissions */
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metadata->max_transmissions = CSMA_MAX_MAC_TRANSMISSIONS;
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} else {
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metadata->max_transmissions =
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packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS);
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}
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metadata->sent = sent;
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metadata->cptr = ptr;
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if(packetbuf_attr(PACKETBUF_ATTR_PACKET_TYPE) ==
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PACKETBUF_ATTR_PACKET_TYPE_ACK) {
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list_push(n->queued_packet_list, q);
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} else {
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list_add(n->queued_packet_list, q);
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}
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/* If q is the first packet in the neighbor's queue, send asap */
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if(list_head(n->queued_packet_list) == q) {
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ctimer_set(&n->transmit_timer, 0, transmit_packet_list, n);
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}
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return;
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}
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memb_free(&metadata_memb, q->ptr);
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PRINTF("csma: could not allocate queuebuf, dropping packet\n");
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}
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memb_free(&packet_memb, q);
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PRINTF("csma: could not allocate queuebuf, dropping packet\n");
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}
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/* The packet allocation failed. Remove and free neighbor entry if empty. */
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if(list_length(n->queued_packet_list) == 0) {
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list_remove(neighbor_list, n);
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memb_free(&neighbor_memb, n);
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}
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PRINTF("csma: could not allocate packet, dropping packet\n");
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} else {
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PRINTF("csma: could not allocate neighbor, dropping packet\n");
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/* Init neighbor entry */
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rimeaddr_copy(&n->addr, addr);
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n->transmissions = 0;
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n->collisions = 0;
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n->deferrals = 0;
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/* Init packet list for this neighbor */
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LIST_STRUCT_INIT(n, queued_packet_list);
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/* Add neighbor to the list */
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list_add(neighbor_list, n);
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}
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mac_call_sent_callback(sent, ptr, MAC_TX_ERR, 1);
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} else {
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PRINTF("csma: send broadcast\n");
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NETSTACK_RDC.send(sent, ptr);
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}
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if(n != NULL) {
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/* Add packet to the neighbor's queue */
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q = memb_alloc(&packet_memb);
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if(q != NULL) {
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q->ptr = memb_alloc(&metadata_memb);
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if(q->ptr != NULL) {
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q->buf = queuebuf_new_from_packetbuf();
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if(q->buf != NULL) {
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struct qbuf_metadata *metadata = (struct qbuf_metadata *)q->ptr;
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/* Neighbor and packet successfully allocated */
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if(packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS) == 0) {
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/* Use default configuration for max transmissions */
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metadata->max_transmissions = CSMA_MAX_MAC_TRANSMISSIONS;
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} else {
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metadata->max_transmissions =
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packetbuf_attr(PACKETBUF_ATTR_MAX_MAC_TRANSMISSIONS);
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}
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metadata->sent = sent;
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metadata->cptr = ptr;
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if(packetbuf_attr(PACKETBUF_ATTR_PACKET_TYPE) ==
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PACKETBUF_ATTR_PACKET_TYPE_ACK) {
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list_push(n->queued_packet_list, q);
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} else {
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list_add(n->queued_packet_list, q);
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}
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/* If q is the first packet in the neighbor's queue, send asap */
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if(list_head(n->queued_packet_list) == q) {
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ctimer_set(&n->transmit_timer, 0, transmit_packet_list, n);
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}
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return;
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}
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memb_free(&metadata_memb, q->ptr);
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PRINTF("csma: could not allocate queuebuf, dropping packet\n");
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}
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memb_free(&packet_memb, q);
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PRINTF("csma: could not allocate queuebuf, dropping packet\n");
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}
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/* The packet allocation failed. Remove and free neighbor entry if empty. */
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if(list_length(n->queued_packet_list) == 0) {
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list_remove(neighbor_list, n);
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memb_free(&neighbor_memb, n);
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}
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PRINTF("csma: could not allocate packet, dropping packet\n");
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} else {
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PRINTF("csma: could not allocate neighbor, dropping packet\n");
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}
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mac_call_sent_callback(sent, ptr, MAC_TX_ERR, 1);
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}
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/*---------------------------------------------------------------------------*/
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static void
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