/***************************************************************************
* The recieve thread doesn't transmit packets. Instead, it queues them
* up on the transmit thread. Every so often, the transmit thread needs
* to flush this transmit queue and send everything.
*
* This is an inherent design issue trying to send things as batches rather
* than individually. It increases latency, but increases performance. We
* don't really care about latency.
***************************************************************************/
void
flush_packets(struct Adapter *adapter,
PACKET_QUEUE *packet_buffers,
PACKET_QUEUE *transmit_queue,
struct Throttler *throttler, uint64_t *packets_sent)
{
uint64_t batch_size;
unsigned is_queue_empty = 0;
while (!is_queue_empty) {
/*
* Only send a few packets at a time, throttled according to the max
* --max-rate set by the user
*/
batch_size = throttler_next_batch(throttler, *packets_sent);
/*
* Send a batch of queued packets
*/
for ( ; batch_size; batch_size--) {
int err;
struct PacketBuffer *p;
/*
* Get the next packet from the transmit queue. This packet was
* put there by a receive thread, and will contain things like
* an ACK or an HTTP request
*/
err = rte_ring_sc_dequeue(transmit_queue, (void**)&p);
if (err) {
is_queue_empty = 1;
break; /* queue is empty, nothing to send */
}
/*
* Actually send the packet
*/
rawsock_send_packet(adapter, p->px, (unsigned)p->length, 1);
/*
* Now that we are done with the packet, put it on the free list
* of buffers that the transmit thread can reuse
*/
for (err=1; err; ) {
err = rte_ring_sp_enqueue(packet_buffers, p);
if (err) {
LOG(0, "transmit queue full (should be impossible)\n");
pixie_usleep(10000);
}
}
/*
* Remember that we sent a packet, which will be used in
* throttling.
*/
(*packets_sent)++;
}
}
}
/***************************************************************************
* Sends the TCP SYN probe packet.
*
* Step 1: format the packet
* Step 2: send it in a portable manner
***************************************************************************/
void
rawsock_send_probe(
struct Adapter *adapter,
unsigned ip_them, unsigned port_them,
unsigned ip_me, unsigned port_me,
unsigned seqno, unsigned flush,
struct TemplateSet *tmplset)
{
/*
* Construct the destination packet
*/
template_set_target(tmplset, ip_them, port_them, ip_me, port_me, seqno);
if (tmplset->length < 60)
tmplset->length = 60;
/*
* Send it
*/
rawsock_send_packet(adapter, tmplset->px, tmplset->length, flush);
}
/***************************************************************************
* Sends the TCP SYN probe packet.
*
* Step 1: format the packet
* Step 2: send it in a portable manner
***************************************************************************/
void
rawsock_send_probe(
struct Adapter *adapter,
unsigned ip_them, unsigned port_them,
unsigned ip_me, unsigned port_me,
unsigned seqno, unsigned flush,
struct TemplateSet *tmplset)
{
unsigned char px[2048];
size_t packet_length;
/*
* Construct the destination packet
*/
template_set_target(tmplset, ip_them, port_them, ip_me, port_me, seqno,
px, sizeof(px), &packet_length);
/*
* Send it
*/
rawsock_send_packet(adapter, px, (unsigned)packet_length, flush);
}
