+ /*
+ * In order to keep track of how much window the client
+ * actually has available, we'd like it to acknowledge each
+ * WINDOW_ADJUST. We can't do that directly, so we accompany
+ * it with a CHANNEL_REQUEST that has to be acknowledged.
+ *
+ * This is only necessary if we're opening the window wide.
+ * If we're not, then throughput is being constrained by
+ * something other than the maximum window size anyway.
+ *
+ * We also only send this if the main channel has finished its
+ * initial CHANNEL_REQUESTs and installed the default
+ * CHANNEL_FAILURE handler, so as not to risk giving it
+ * unexpected CHANNEL_FAILUREs.
+ */
+ if (newwin == c->v.v2.locmaxwin &&
+ ssh->packet_dispatch[SSH2_MSG_CHANNEL_FAILURE]) {
+ pktout = ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+ ssh2_pkt_adduint32(pktout, c->remoteid);
+ ssh2_pkt_addstring(pktout, "winadj@putty.projects.tartarus.org");
+ ssh2_pkt_addbool(pktout, TRUE);
+ ssh2_pkt_send(ssh, pktout);
+
+ /*
+ * CHANNEL_FAILURE doesn't come with any indication of
+ * what message caused it, so we have to keep track of the
+ * outstanding CHANNEL_REQUESTs ourselves.
+ */
+ wa = snew(struct winadj);
+ wa->size = newwin - c->v.v2.locwindow;
+ wa->next = NULL;
+ if (!c->v.v2.winadj_head)
+ c->v.v2.winadj_head = wa;
+ else
+ c->v.v2.winadj_tail->next = wa;
+ c->v.v2.winadj_tail = wa;
+ if (c->v.v2.throttle_state != UNTHROTTLED)
+ c->v.v2.throttle_state = UNTHROTTLING;
+ } else {
+ /* Pretend the WINDOW_ADJUST was acked immediately. */
+ c->v.v2.remlocwin = newwin;
+ c->v.v2.throttle_state = THROTTLED;
+ }