- struct mbuf *ifm, *ifqt;
-
- DEBUG_CALL("if_start");
-
- if (if_queued == 0)
- return; /* Nothing to do */
-
- again:
- /* check if we can really output */
- if (!slirp_can_output())
- return;
-
- /*
- * See which queue to get next packet from
- * If there's something in the fastq, select it immediately
- */
- if (if_fastq.ifq_next != &if_fastq) {
- ifm = if_fastq.ifq_next;
- } else {
- /* Nothing on fastq, see if next_m is valid */
- if (next_m != &if_batchq)
- ifm = next_m;
- else
- ifm = if_batchq.ifq_next;
-
- /* Set which packet to send on next iteration */
- next_m = ifm->ifq_next;
- }
- /* Remove it from the queue */
- ifqt = ifm->ifq_prev;
- remque(ifm);
- --if_queued;
-
- /* If there are more packets for this session, re-queue them */
- if (ifm->ifs_next != /* ifm->ifs_prev != */ ifm) {
- insque(ifm->ifs_next, ifqt);
- ifs_remque(ifm);
- }
-
- /* Update so_queued */
- if (ifm->ifq_so) {
- if (--ifm->ifq_so->so_queued == 0)
- /* If there's no more queued, reset nqueued */
- ifm->ifq_so->so_nqueued = 0;
- }
-
- /* Encapsulate the packet for sending */
- if_encap((uint8_t *)ifm->m_data, ifm->m_len);
+ 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;
+ }