+/* --- @p_updateaddr@ --- *
+ *
+ * Arguments: @peer *p@ = pointer to peer block
+ * @const addr *a@ = address to associate with this peer
+ *
+ * Returns: Zero if the address was changed; @+1@ if it was already
+ * right.
+ *
+ * Use: Updates our idea of @p@'s address.
+ */
+
+int p_updateaddr(peer *p, const addr *a)
+{
+ peer *q;
+ peer_byaddr *pa, *qa;
+ unsigned f;
+
+ /* --- Figure out how to proceed --- *
+ *
+ * If this address already belongs to a different peer, then swap the
+ * addresses over. This doesn't leave the displaced peer in an especially
+ * good state, but it ought to get sorted out soon enough.
+ */
+
+ pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f);
+ if (f && pa->p == p)
+ return (+1);
+ else if (!f) {
+ T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
+ am_remove(&byaddr, p->byaddr);
+ p->byaddr = pa; p->spec.sa = *a; pa->p = p;
+ a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+ return (0);
+ } else {
+ q = pa->p; qa = p->byaddr;
+ T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
+ p_name(p), p_name(q)); )
+ q->byaddr = qa; qa->p = q; q->spec.sa = p->spec.sa;
+ p->byaddr = pa; pa->p = p; p->spec.sa = *a;
+ a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
+ a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
+ return (0);
+ }
+}
+