[src/trunk]: src/sys/net Make complex RTM_CHANGE code understandable

[ozaki-r <ozaki-r%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5a0390f1d413
branches:  trunk
changeset: 346600:5a0390f1d413
user:      ozaki-r <ozaki-r%NetBSD.org@localhost>
date:      Thu Jul 21 03:45:56 2016 +0000

description:
Make complex RTM_CHANGE code understandable

Tests for route change added recently would reduce the possibility of
regressions.

Reviewed by ryo@

diffstat:

 sys/net/rtsock.c |  70 ++++++++++++++++++++++++++++++++++++++++----------------
 1 files changed, 50 insertions(+), 20 deletions(-)

diffs (98 lines):

diff -r f385bc1ea542 -r 5a0390f1d413 sys/net/rtsock.c
--- a/sys/net/rtsock.c  Thu Jul 21 02:02:30 2016 +0000
+++ b/sys/net/rtsock.c  Thu Jul 21 03:45:56 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rtsock.c,v 1.191 2016/07/07 09:32:02 ozaki-r Exp $     */
+/*     $NetBSD: rtsock.c,v 1.192 2016/07/21 03:45:56 ozaki-r 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 1.191 2016/07/07 09:32:02 ozaki-r Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rtsock.c,v 1.192 2016/07/21 03:45:56 ozaki-r Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_inet.h"
@@ -539,6 +539,53 @@
        return 0;
 }
 
+static struct ifaddr *
+route_output_get_ifa(const struct rt_addrinfo info, const struct rtentry *rt,
+    struct ifnet **ifp)
+{
+       struct ifaddr *ifa = NULL;
+
+       *ifp = NULL;
+       if (info.rti_info[RTAX_IFP] != NULL) {
+               ifa = ifa_ifwithnet(info.rti_info[RTAX_IFP]);
+               if (ifa == NULL)
+                       goto next;
+               *ifp = ifa->ifa_ifp;
+               if (info.rti_info[RTAX_IFA] == NULL &&
+                   info.rti_info[RTAX_GATEWAY] == NULL)
+                       goto next;
+               if (info.rti_info[RTAX_IFA] == NULL) {
+                       /* route change <dst> <gw> -ifp <if> */
+                       ifa = ifaof_ifpforaddr(info.rti_info[RTAX_GATEWAY],
+                           *ifp);
+               } else {
+                       /* route change <dst> -ifp <if> -ifa <addr> */
+                       ifa = ifa_ifwithaddr(info.rti_info[RTAX_IFA]);
+                       if (ifa != NULL)
+                               goto out;
+                       ifa = ifaof_ifpforaddr(info.rti_info[RTAX_IFA],
+                           *ifp);
+               }
+               goto out;
+       }
+next:
+       if (info.rti_info[RTAX_IFA] != NULL) {
+               /* route change <dst> <gw> -ifa <addr> */
+               ifa = ifa_ifwithaddr(info.rti_info[RTAX_IFA]);
+               if (ifa != NULL)
+                       goto out;
+       }
+       if (info.rti_info[RTAX_GATEWAY] != NULL) {
+               /* route change <dst> <gw> */
+               ifa = ifa_ifwithroute(rt->rt_flags, rt_getkey(rt),
+                   info.rti_info[RTAX_GATEWAY]);
+       }
+out:
+       if (ifa != NULL && *ifp == NULL)
+               *ifp = ifa->ifa_ifp;
+       return ifa;
+}
+
 /*ARGSUSED*/
 int
 COMPATNAME(route_output)(struct mbuf *m, struct socket *so)
@@ -783,24 +830,7 @@
                        /* new gateway could require new ifaddr, ifp;
                           flags may also be different; ifp may be specified
                           by ll sockaddr when protocol address is ambiguous */
-                       if (info.rti_info[RTAX_IFP] &&
-                           (ifa = ifa_ifwithnet(info.rti_info[RTAX_IFP])) &&
-                           (ifp = ifa->ifa_ifp) && (info.rti_info[RTAX_IFA] ||
-                           info.rti_info[RTAX_GATEWAY])) {
-                               if (info.rti_info[RTAX_IFA] == NULL ||
-                                   (ifa = ifa_ifwithaddr(
-                                   info.rti_info[RTAX_IFA])) == NULL)
-                                       ifa = ifaof_ifpforaddr(
-                                           info.rti_info[RTAX_IFA] ?
-                                           info.rti_info[RTAX_IFA] :
-                                           info.rti_info[RTAX_GATEWAY], ifp);
-                       } else if ((info.rti_info[RTAX_IFA] &&
-                           (ifa = ifa_ifwithaddr(info.rti_info[RTAX_IFA]))) ||
-                           (info.rti_info[RTAX_GATEWAY] &&
-                           (ifa = ifa_ifwithroute(rt->rt_flags,
-                           rt_getkey(rt), info.rti_info[RTAX_GATEWAY])))) {
-                               ifp = ifa->ifa_ifp;
-                       }
+                       ifa = route_output_get_ifa(info, rt, &ifp);
                        if (ifa) {
                                struct ifaddr *oifa = rt->rt_ifa;
                                if (oifa != ifa) {