network - Fix udp multicast assertion & mplock for ip_output

* Fix an assertion which is no longer valid, the MP lock is no longer
  held by the caller when passing a multicast packet into ip_output.

* Move the mp lock for udp multicast packets inward.  The underlying code
  still isn't mpsafe.

Reported-by: "Edward O'Callaghan" <eocallaghan@auroraux.org>

diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index 5be2b83..3c4a7e0 100644 (file)
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -306,17 +306,6 @@ ip_output(struct mbuf *m0, struct mbuf *opt, struct route *ro,
 reroute:
        pkt_dst = next_hop ? next_hop->sin_addr : ip->ip_dst;
 
-#ifdef INVARIANTS
-       if (IN_MULTICAST(ntohl(pkt_dst.s_addr))) {
-               /*
-                * XXX
-                * Multicast is not MPSAFE yet.  Caller must hold
-                * BGL when output a multicast IP packet.
-                */
-               ASSERT_MP_LOCK_HELD(curthread);
-       }
-#endif
-
        dst = (struct sockaddr_in *)&ro->ro_dst;
        /*
         * If there is a cached route,
@@ -463,10 +452,14 @@ reroute:
                                 */
                                if (!rsvp_on)
                                        imo = NULL;
-                               if (ip_mforward &&
-                                   ip_mforward(ip, ifp, m, imo) != 0) {
-                                       m_freem(m);
-                                       goto done;
+                               if (ip_mforward) {
+                                       get_mplock();
+                                       if (ip_mforward(ip, ifp, m, imo) != 0) {
+                                               m_freem(m);
+                                               rel_mplock();
+                                               goto done;
+                                       }
+                                       rel_mplock();
                                }
                        }
                }
@@ -2186,6 +2179,8 @@ ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst,
                        dst->sin_family = AF_INET;
                }
 #endif
+               get_mplock();   /* is if_simloop() mpsafe yet? */
                if_simloop(ifp, copym, dst->sin_family, 0);
+               rel_mplock();
        }
 }