Repair botched retry loop when generating RTM_PROPOSAL

messages at startup. Reproducible situation found on
vnet(4) and fix tested by jca@.

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 29ed2bc..5302f87 100644 (file)
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dhclient.c,v 1.549 2018/01/29 15:18:05 krw Exp $      */
+/*     $OpenBSD: dhclient.c,v 1.550 2018/01/29 23:16:36 krw Exp $      */
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -2417,20 +2417,24 @@ take_charge(struct interface_info *ifi, int routefd)
        rtm.rtm_msglen = sizeof(rtm);
        rtm.rtm_tableid = ifi->rdomain;
        rtm.rtm_index = ifi->index;
-       rtm.rtm_seq = ifi->xid = arc4random();
        rtm.rtm_priority = RTP_PROPOSAL_DHCLIENT;
        rtm.rtm_addrs = 0;
        rtm.rtm_flags = RTF_UP | RTF_PROTO3;
 
+       rtm.rtm_seq = ifi->xid = arc4random();
+       if (write(routefd, &rtm, sizeof(rtm)) == -1)
+               fatal("write(routefd)");
+
        retries = 0;
        while ((ifi->flags & IFI_IN_CHARGE) == 0) {
-               if (write(routefd, &rtm, sizeof(rtm)) == -1)
-                       fatal("write(routefd)");
                time(&cur_time);
                if ((cur_time - start_time) > 3) {
                        if (++retries <= 3) {
                                if (time(&start_time) == -1)
                                        fatal("time");
+                               rtm.rtm_seq = ifi->xid = arc4random();
+                               if (write(routefd, &rtm, sizeof(rtm)) == -1)
+                                       fatal("write(routefd)");
                        } else {
                                fatalx("failed to take charge");
                        }