let pfsync_request_update actually retry when it overfills a packet.

a continue in the middle of a do { } while (0) loop is effectively
a break, it doesnt restart the loop.

without the retry, the code leaked update messages which in turn
made pool_destroy in pfsync destroy trip over a kassert cos items
were still out.

found by and fix tested by hrvoje popovski
ok sashan@

diff --git a/sys/net/if_pfsync.c b/sys/net/if_pfsync.c
index eaaaa26..744a7ca 100644 (file)
--- a/sys/net/if_pfsync.c
+++ b/sys/net/if_pfsync.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_pfsync.c,v 1.295 2021/06/23 06:53:51 dlg Exp $     */
+/*     $OpenBSD: if_pfsync.c,v 1.296 2021/06/25 23:48:30 dlg Exp $     */
 
 /*
  * Copyright (c) 2002 Michael Shalayeff
@@ -2232,6 +2232,7 @@ pfsync_request_update(u_int32_t creatorid, u_int64_t id)
        struct pfsync_softc *sc = pfsyncif;
        struct pfsync_upd_req_item *item;
        size_t nlen, sc_len;
+       int retry;
 
        /*
         * this code does nothing to prevent multiple update requests for the
@@ -2247,7 +2248,7 @@ pfsync_request_update(u_int32_t creatorid, u_int64_t id)
        item->ur_msg.id = id;
        item->ur_msg.creatorid = creatorid;
 
-       do {
+       for (;;) {
                mtx_enter(&sc->sc_upd_req_mtx);
 
                nlen = sizeof(struct pfsync_upd_req);
@@ -2255,16 +2256,19 @@ pfsync_request_update(u_int32_t creatorid, u_int64_t id)
                        nlen += sizeof(struct pfsync_subheader);
 
                sc_len = atomic_add_long_nv(&sc->sc_len, nlen);
-               if (sc_len > sc->sc_if.if_mtu) {
+               retry = (sc_len > sc->sc_if.if_mtu);
+               if (retry)
                        atomic_sub_long(&sc->sc_len, nlen);
-                       mtx_leave(&sc->sc_upd_req_mtx);
-                       pfsync_sendout();
-                       continue;
-               }
+               else
+                       TAILQ_INSERT_TAIL(&sc->sc_upd_req_list, item, ur_entry);
 
-               TAILQ_INSERT_TAIL(&sc->sc_upd_req_list, item, ur_entry);
                mtx_leave(&sc->sc_upd_req_mtx);
-       } while (0);
+
+               if (!retry)
+                       break;
+
+               pfsync_sendout();
+       }
 
        schednetisr(NETISR_PFSYNC);
 }