commit fd352ad5f1b1b5bebf381644b212a7ddfb5be007
from: smytht <smytht@users.noreply.github.com>
via: GitHub <noreply@github.com>
date: Fri Oct 11 17:31:22 2024 UTC

 if.c - vlan parent devices automatically disable 

disable the child interface and change parent and enable interface after the change made...

issue reported by Tom... fix authored by stsp 
tested by Tom and reviewed OK Tom and OK Chris

commit - 21775861a453dd25aacb50e76637bdec1d1a31cf
commit + fd352ad5f1b1b5bebf381644b212a7ddfb5be007
blob - 031502710a5c7be123a4d9e6bd7367f75378b4f7
blob + c03769db2af537aa32431b142fbc3be5c9b4a647
--- if.c
+++ if.c
@@ -2345,7 +2345,8 @@ intrtlabel(char *ifname, int ifs, int argc, char **arg
 int
 intparent(char *ifname, int ifs, int argc, char **argv)
 {
-	int set;
+	int set, ret;
+	unsigned long cmd;
 	struct if_parent ifp;
 
 	if (NO_ARG(argv[0])) {
@@ -2374,9 +2375,22 @@ intparent(char *ifname, int ifs, int argc, char **argv
 		return 0;
 	}
 
-	if (ioctl(ifs, set ? SIOCSIFPARENT : SIOCDIFPARENT, &ifp) == -1)
-		printf("%% intparent: SIOC%sIFPARENT: %s\n", set ? "S" : "D",
-		    strerror(errno));
+	cmd = (set ? SIOCSIFPARENT : SIOCDIFPARENT);
+	ret = ioctl(ifs, cmd, &ifp);
+	if (ret == -1) {
+	if (errno == EBUSY) {
+	                int flags = get_ifflags(ifname, ifs);
+	                  if (flags & IFF_UP) {
+                        /* Toggle interface down and retry. and bring the interface back up*/
+	                        set_ifflags(ifname, ifs, flags & ~IFF_UP);
+	                        ret = ioctl(ifs, cmd, &ifp);
+	                        set_ifflags(ifname, ifs, flags);
+	                }
+	        }
+	        if (ret == -1)
+	                printf("%% intparent: SIOC%sIFPARENT: %s\n",
+	                    set ? "S" : "D", strerror(errno));
+	}
 
 	return 0;
 }