ipv6: Implement different admin modes for automatic flow labels
Change the meaning of net.ipv6.auto_flowlabels to provide a mode for
automatic flow labels generation. There are four modes:
0: flow labels are disabled
1: flow labels are enabled, sockets can opt-out
2: flow labels are allowed, sockets can opt-in
3: flow labels are enabled and enforced, no opt-out for sockets
np->autoflowlabel is initialized according to the sysctl value.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 3e334b3..c02c1c0 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -707,36 +707,69 @@
}
#if IS_ENABLED(CONFIG_IPV6)
+
+/* Sysctl settings for net ipv6.auto_flowlabels */
+#define IP6_AUTO_FLOW_LABEL_OFF 0
+#define IP6_AUTO_FLOW_LABEL_OPTOUT 1
+#define IP6_AUTO_FLOW_LABEL_OPTIN 2
+#define IP6_AUTO_FLOW_LABEL_FORCED 3
+
+#define IP6_AUTO_FLOW_LABEL_MAX IP6_AUTO_FLOW_LABEL_FORCED
+
+#define IP6_DEFAULT_AUTO_FLOW_LABELS IP6_AUTO_FLOW_LABEL_OFF
+
static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,
__be32 flowlabel, bool autolabel,
struct flowi6 *fl6)
{
- if (!flowlabel && (autolabel || net->ipv6.sysctl.auto_flowlabels)) {
- u32 hash;
+ u32 hash;
- hash = skb_get_hash_flowi6(skb, fl6);
+ if (flowlabel ||
+ net->ipv6.sysctl.auto_flowlabels == IP6_AUTO_FLOW_LABEL_OFF ||
+ (!autolabel &&
+ net->ipv6.sysctl.auto_flowlabels != IP6_AUTO_FLOW_LABEL_FORCED))
+ return flowlabel;
- /* Since this is being sent on the wire obfuscate hash a bit
- * to minimize possbility that any useful information to an
- * attacker is leaked. Only lower 20 bits are relevant.
- */
- hash ^= hash >> 12;
+ hash = skb_get_hash_flowi6(skb, fl6);
- flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
+ /* Since this is being sent on the wire obfuscate hash a bit
+ * to minimize possbility that any useful information to an
+ * attacker is leaked. Only lower 20 bits are relevant.
+ */
+ rol32(hash, 16);
- if (net->ipv6.sysctl.flowlabel_state_ranges)
- flowlabel |= IPV6_FLOWLABEL_STATELESS_FLAG;
- }
+ flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
+
+ if (net->ipv6.sysctl.flowlabel_state_ranges)
+ flowlabel |= IPV6_FLOWLABEL_STATELESS_FLAG;
return flowlabel;
}
+
+static inline int ip6_default_np_autolabel(struct net *net)
+{
+ switch (net->ipv6.sysctl.auto_flowlabels) {
+ case IP6_AUTO_FLOW_LABEL_OFF:
+ case IP6_AUTO_FLOW_LABEL_OPTIN:
+ default:
+ return 0;
+ case IP6_AUTO_FLOW_LABEL_OPTOUT:
+ case IP6_AUTO_FLOW_LABEL_FORCED:
+ return 1;
+ }
+}
#else
static inline void ip6_set_txhash(struct sock *sk) { }
static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,
- __be32 flowlabel, bool autolabel)
+ __be32 flowlabel, bool autolabel,
+ struct flowi6 *fl6)
{
return flowlabel;
}
+static inline int ip6_default_np_autolabel(struct net *net)
+{
+ return 0;
+}
#endif