From: Roy Marples <roy@marples.name>
Date: Mon, 3 Aug 2020 15:15:39 +0000 (+0100)
Subject: Linux: IP6 forwaring only applies to "all" interface
X-Git-Tag: v9.2.0~36
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=670f1d7519c50679bc4627b57b3250ad56b02898;p=thirdparty%2Fdhcpcd.git

Linux: IP6 forwaring only applies to "all" interface

Per interface forwarding is apparently only for setting things
like IsRouter in NA messages.
---

diff --git a/src/ipv6.c b/src/ipv6.c
index c42b3d6d..5a8b08be 100644
--- a/src/ipv6.c
+++ b/src/ipv6.c
@@ -1092,33 +1092,22 @@ ipv6_anyglobal(struct interface *sifp)
 	struct interface *ifp;
 	struct ipv6_state *state;
 	struct ipv6_addr *ia;
-#ifdef BSD
 	bool forwarding;
 
-#if defined(PRIVSEP) && defined(HAVE_PLEDGE)
+	/* BSD forwarding is either on or off.
+	 * Linux forwarding is technically the same as it's
+	 * configured by the "all" interface.
+	 * Per interface only affects IsRouter of NA messages. */
+#if defined(PRIVSEP) && (defined(HAVE_PLEDGE) || defined(__linux__))
 	if (IN_PRIVSEP(sifp->ctx))
-		forwarding = ps_root_ip6forwarding(sifp->ctx, NULL) == 1;
+		forwarding = ps_root_ip6forwarding(sifp->ctx, "all") != 0;
 	else
 #endif
-		forwarding = ip6_forwarding(NULL) == 1;
-#endif
-
+		forwarding = ip6_forwarding("all") != 0;
 
 	TAILQ_FOREACH(ifp, sifp->ctx->ifaces, next) {
-#ifdef BSD
 		if (ifp != sifp && !forwarding)
 			continue;
-#else
-#if defined(PRIVSEP) && defined(__linux__)
-	if (IN_PRIVSEP(sifp->ctx)) {
-		if (ifp != sifp &&
-		    ps_root_ip6forwarding(sifp->ctx, ifp->name) != 1)
-			continue;
-	} else
-#endif
-		if (ifp != sifp && ip6_forwarding(ifp->name) != 1)
-			continue;
-#endif
 
 		state = IPV6_STATE(ifp);
 		if (state == NULL)
diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index 009792dc..d1cc4efa 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -544,11 +544,11 @@ ipv6nd_advertise(struct ipv6_addr *ia)
 	na->nd_na_flags_reserved = ND_NA_FLAG_OVERRIDE;
 #if defined(PRIVSEP) && (defined(__linux__) || defined(HAVE_PLEDGE))
 	if (IN_PRIVSEP(ctx)) {
-		if (ps_root_ip6forwarding(ctx, ifp->name) == 1)
+		if (ps_root_ip6forwarding(ctx, ifp->name) != 0)
 			na->nd_na_flags_reserved |= ND_NA_FLAG_ROUTER;
 	} else
 #endif
-	if (ip6_forwarding(ifp->name) == 1)
+	if (ip6_forwarding(ifp->name) != 0)
 		na->nd_na_flags_reserved |= ND_NA_FLAG_ROUTER;
 	na->nd_na_target = ia->addr;