if: Ignore TAP interfaces by default

TAP interfaces are virtual ethernet and not really distinguishable
from real interfaces other than the interface name.

On BSD the interfaces are always called tapN.

1 files changed, 12 insertions, 10 deletions

diff --git a/src/if.c b/src/if.c
index c483f046..b9cf63ed 100644
--- a/src/if.c
+++ b/src/if.c
@@ -405,13 +405,6 @@ if_discover(struct dhcpcd_ctx *ctx, struct ifaddrs **ifaddrs,
 			continue;
 #endif
 
-		/* Don't allow loopback or pointopoint unless explicit */
-		if (ifa->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) {
-			if ((argc == 0 || argc == -1) &&
-			    ctx->ifac == 0 && !if_hasconf(ctx, spec.devname))
-				active = IF_INACTIVE;
-		}
-
 		if (if_vimaster(ctx, spec.devname) == 1) {
 			logfunc_t *logfunc = argc != 0 ? logerrx : logdebugx;
 			logfunc("%s: is a Virtual Interface Master, skipping",
@@ -419,6 +412,17 @@ if_discover(struct dhcpcd_ctx *ctx, struct ifaddrs **ifaddrs,
 			continue;
 		}
 
+#define	IF_NOCONF	((argc == 0 || argc == -1) && ctx->ifac == 0 && \
+			 !if_hasconf(ctx, spec.devname))
+
+		/* Don't allow loopback or pointopoint unless explicit.
+		 * Don't allow some reserved interface names unless explicit. */
+		if (IF_NOCONF) {
+			if (ifa->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT) ||
+			    if_ignore(spec.drvname))
+				active = IF_INACTIVE;
+		}
+
 		ifp = calloc(1, sizeof(*ifp));
 		if (ifp == NULL) {
 			logerr(__func__);
@@ -495,9 +499,7 @@ if_discover(struct dhcpcd_ctx *ctx, struct ifaddrs **ifaddrs,
 #endif
 			default:
 				/* Don't allow unless explicit */
-				if ((argc == 0 || argc == -1) &&
-				    ctx->ifac == 0 &&
-				    !if_hasconf(ctx, ifp->name))
+				if (IF_NOCONF)
 					active = IF_INACTIVE;
 				if (active)
 					logwarnx("%s: unsupported"