Example #1
0
/*
 * 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;
}
Example #2
0
/*
 * 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;
}