/*
* Send a packet
* We choose a packet based on its position in the output queues;
* If there are packets on the fastq, they are sent FIFO, before
* everything else. Otherwise we choose the first packet from the
* batchq and send it. the next packet chosen will be from the session
* after this one, then the session after that one, and so on.. So,
* for example, if there are 3 ftp session's fighting for bandwidth,
* one packet will be sent from the first session, then one packet
* from the second session, then one packet from the third, then back
* to the first, etc. etc.
*/
void if_start(Slirp *slirp)
{
uint64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
bool from_batchq, next_from_batchq;
struct mbuf *ifm, *ifm_next, *ifqt;
DEBUG_CALL("if_start");
if (slirp->if_start_busy) {
return;
}
slirp->if_start_busy = true;
if (slirp->if_fastq.ifq_next != &slirp->if_fastq) {
ifm_next = slirp->if_fastq.ifq_next;
next_from_batchq = false;
} else if (slirp->next_m != &slirp->if_batchq) {
/* Nothing on fastq, pick up from batchq via next_m */
ifm_next = slirp->next_m;
next_from_batchq = true;
} else {
ifm_next = NULL;
}
while (ifm_next) {
ifm = ifm_next;
from_batchq = next_from_batchq;
ifm_next = ifm->ifq_next;
if (ifm_next == &slirp->if_fastq) {
/* No more packets in fastq, switch to batchq */
ifm_next = slirp->next_m;
next_from_batchq = true;
}
if (ifm_next == &slirp->if_batchq) {
/* end of batchq */
ifm_next = NULL;
}
/* Try to send packet unless it already expired */
if (ifm->expiration_date >= now && !if_encap(slirp, ifm)) {
/* Packet is delayed due to pending ARP resolution */
continue;
}
if (ifm == slirp->next_m) {
/* Set which packet to send on next iteration */
slirp->next_m = ifm->ifq_next;
}
/* Remove it from the queue */
ifqt = ifm->ifq_prev;
remque(ifm);
/* If there are more packets for this session, re-queue them */
if (ifm->ifs_next != ifm) {
struct mbuf *next = ifm->ifs_next;
insque(next, ifqt);
ifs_remque(ifm);
if (!from_batchq) {
/* Next packet in fastq is from the same session */
ifm_next = next;
next_from_batchq = false;
} else if (slirp->next_m == &slirp->if_batchq) {
/* Set next_m and ifm_next if the session packet is now the
* only one on batchq */
slirp->next_m = ifm_next = next;
}
}
/* Update so_queued */
if (ifm->ifq_so && --ifm->ifq_so->so_queued == 0) {
/* If there's no more queued, reset nqueued */
ifm->ifq_so->so_nqueued = 0;
}
m_free(ifm);
}
slirp->if_start_busy = false;
}
/*
* Send a packet
* We choose a packet based on it's position in the output queues;
* If there are packets on the fastq, they are sent FIFO, before
* everything else. Otherwise we choose the first packet from the
* batchq and send it. the next packet chosen will be from the session
* after this one, then the session after that one, and so on.. So,
* for example, if there are 3 ftp session's fighting for bandwidth,
* one packet will be sent from the first session, then one packet
* from the second session, then one packet from the third, then back
* to the first, etc. etc.
*/
void if_start(Slirp *slirp)
{
uint64_t now = qemu_get_clock_ns(rt_clock);
int requeued = 0;
bool from_batchq = false;
struct mbuf *ifm, *ifqt;
DEBUG_CALL("if_start");
while (slirp->if_queued) {
/* check if we can really output */
if (!slirp_can_output(slirp->opaque))
return;
/*
* See which queue to get next packet from
* If there's something in the fastq, select it immediately
*/
if (slirp->if_fastq.ifq_next != &slirp->if_fastq) {
ifm = slirp->if_fastq.ifq_next;
} else {
/* Nothing on fastq, see if next_m is valid */
if (slirp->next_m != &slirp->if_batchq) {
ifm = slirp->next_m;
} else {
ifm = slirp->if_batchq.ifq_next;
}
from_batchq = true;
}
slirp->if_queued--;
/* Try to send packet unless it already expired */
if (ifm->expiration_date >= now && !if_encap(slirp, ifm)) {
/* Packet is delayed due to pending ARP resolution */
requeued++;
continue;
}
if (from_batchq) {
/* Set which packet to send on next iteration */
slirp->next_m = ifm->ifq_next;
}
/* Remove it from the queue */
ifqt = ifm->ifq_prev;
remque(ifm);
/* If there are more packets for this session, re-queue them */
if (ifm->ifs_next != ifm) {
insque(ifm->ifs_next, ifqt);
ifs_remque(ifm);
}
/* Update so_queued */
if (ifm->ifq_so && --ifm->ifq_so->so_queued == 0) {
/* If there's no more queued, reset nqueued */
ifm->ifq_so->so_nqueued = 0;
}
m_free(ifm);
}
slirp->if_queued = requeued;
}