[src/trunk]: src/sys/net Avoid DIAGNOSTIC warning with previous fix and simpl...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0114d87f8c24
branches:  trunk
changeset: 825124:0114d87f8c24
user:      christos <christos%NetBSD.org@localhost>
date:      Fri Jun 30 18:28:31 2017 +0000

description:
Avoid DIAGNOSTIC warning with previous fix and simplify it (don't require
memory alloc/free).

diffstat:

 sys/net/rtsock.c |  64 +++++++++++++++++++++++++++----------------------------
 1 files changed, 31 insertions(+), 33 deletions(-)

diffs (108 lines):

diff -r 1474e12354bf -r 0114d87f8c24 sys/net/rtsock.c
--- a/sys/net/rtsock.c  Fri Jun 30 11:55:56 2017 +0000
+++ b/sys/net/rtsock.c  Fri Jun 30 18:28:31 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rtsock.c,v 1.225 2017/06/30 09:11:22 ozaki-r Exp $     */
+/*     $NetBSD: rtsock.c,v 1.226 2017/06/30 18:28:31 christos Exp $    */
 
 /*
  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
@@ -61,7 +61,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.225 2017/06/30 09:11:22 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.226 2017/06/30 18:28:31 christos Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -721,6 +721,24 @@
        return error;
 }
 
+static socklen_t
+sa_addrlen(const struct sockaddr *sa)
+{
+
+       switch (sa->sa_family) {
+#ifdef INET
+       case AF_INET:
+               return sizeof(struct sockaddr_in);
+#endif
+#ifdef INET6
+       case AF_INET6:
+               return sizeof(struct sockaddr_in6);
+#endif
+       default:
+               return 0;
+       }
+}
+
 /*ARGSUSED*/
 int
 COMPATNAME(route_output)(struct mbuf *m, struct socket *so)
@@ -736,7 +754,7 @@
        struct sockaddr_dl sdl;
        int bound = curlwp_bind();
        bool do_rt_free = false;
-       struct sockaddr *netmask = NULL;
+       struct sockaddr_storage netmask;
 
 #define senderr(e) do { error = e; goto flush;} while (/*CONSTCOND*/ 0)
        if (m == NULL || ((m->m_len < sizeof(int32_t)) &&
@@ -796,36 +814,18 @@
 
        /*
         * route(8) passes a sockaddr truncated with prefixlen.
-        * The kernel doesn't expect such sockaddr and need to restore
-        * the original length of the sockaddr.
+        * The kernel doesn't expect such sockaddr and need to 
+        * use a buffer that is big enough for the sockaddr expected
+        * (padded with 0's). We keep the original length of the sockaddr.
         */
        if (info.rti_info[RTAX_NETMASK]) {
-               size_t sa_len = 0;
-               int af = info.rti_info[RTAX_NETMASK]->sa_family;
-
-               switch (af) {
-#ifdef INET
-               case AF_INET:
-                       sa_len = sizeof(struct sockaddr_in);
-                       break;
-#endif
-#ifdef INET6
-               case AF_INET6:
-                       sa_len = sizeof(struct sockaddr_in6);
-                       break;
-#endif
-               default:
-                       break;
-               }
-               if (sa_len != 0 &&
-                   sa_len > info.rti_info[RTAX_NETMASK]->sa_len) {
-                       netmask = sockaddr_alloc(af, sa_len, M_WAITOK|M_ZERO);
-                       sockaddr_copy(netmask,
-                           info.rti_info[RTAX_NETMASK]->sa_len,
-                           info.rti_info[RTAX_NETMASK]);
-                       /* Restore original sa_len */
-                       netmask->sa_len = info.rti_info[RTAX_NETMASK]->sa_len;
-                       info.rti_info[RTAX_NETMASK] = netmask;
+               socklen_t sa_len = sa_addrlen(info.rti_info[RTAX_NETMASK]);
+               socklen_t masklen = info.rti_info[RTAX_NETMASK]->sa_len;
+               if (sa_len != 0 && sa_len > masklen) {
+                       KASSERT(sa_len <= sizeof(netmask));
+                       memcpy(&netmask, info.rti_info[RTAX_NETMASK], masklen);
+                       memset((char *)&netmask + masklen, 0, sa_len - masklen);
+                       info.rti_info[RTAX_NETMASK] = sstocsa(&netmask);
                }
        }
 
@@ -1067,8 +1067,6 @@
     }
 out:
        curlwp_bindx(bound);
-       if (netmask)
-               sockaddr_free(netmask);
        return error;
 }