1 files changed, 65 insertions, 4 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 46d614b611db..a11fd4d67832 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -236,6 +236,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.enhanced_dad           = 1,
 	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 	.disable_policy		= 0,
+	.rpl_seg_enabled	= 0,
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -290,6 +291,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.enhanced_dad           = 1,
 	.addr_gen_mode		= IN6_ADDR_GEN_MODE_EUI64,
 	.disable_policy		= 0,
+	.rpl_seg_enabled	= 0,
 };
 
 /* Check if link is ready: is it up and is a valid qdisc available */
@@ -3301,7 +3303,7 @@ static void addrconf_addr_gen(struct inet6_dev *idev, bool prefix_route)
 	switch (idev->cnf.addr_gen_mode) {
 	case IN6_ADDR_GEN_MODE_RANDOM:
 		ipv6_gen_mode_random_init(idev);
-		/* fallthrough */
+		fallthrough;
 	case IN6_ADDR_GEN_MODE_STABLE_PRIVACY:
 		if (!ipv6_generate_stable_address(&addr, 0, idev))
 			addrconf_add_linklocal(idev, &addr,
@@ -3523,9 +3525,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event,
 			break;
 
 		run_pending = 1;
-
-		/* fall through */
-
+		fallthrough;
 	case NETDEV_UP:
 	case NETDEV_CHANGE:
 		if (dev->flags & IFF_SLAVE)
@@ -4400,6 +4400,59 @@ int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr)
 }
 #endif
 
+/* RFC6554 has some algorithm to avoid loops in segment routing by
+ * checking if the segments contains any of a local interface address.
+ *
+ * Quote:
+ *
+ * To detect loops in the SRH, a router MUST determine if the SRH
+ * includes multiple addresses assigned to any interface on that router.
+ * If such addresses appear more than once and are separated by at least
+ * one address not assigned to that router.
+ */
+int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
+			  unsigned char nsegs)
+{
+	const struct in6_addr *addr;
+	int i, ret = 0, found = 0;
+	struct inet6_ifaddr *ifp;
+	bool separated = false;
+	unsigned int hash;
+	bool hash_found;
+
+	rcu_read_lock();
+	for (i = 0; i < nsegs; i++) {
+		addr = &segs[i];
+		hash = inet6_addr_hash(net, addr);
+
+		hash_found = false;
+		hlist_for_each_entry_rcu(ifp, &inet6_addr_lst[hash], addr_lst) {
+			if (!net_eq(dev_net(ifp->idev->dev), net))
+				continue;
+
+			if (ipv6_addr_equal(&ifp->addr, addr)) {
+				hash_found = true;
+				break;
+			}
+		}
+
+		if (hash_found) {
+			if (found > 1 && separated) {
+				ret = 1;
+				break;
+			}
+
+			separated = false;
+			found++;
+		} else {
+			separated = true;
+		}
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
 /*
  *	Periodic address status verification
  */
@@ -5469,6 +5522,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_ADDR_GEN_MODE] = cnf->addr_gen_mode;
 	array[DEVCONF_DISABLE_POLICY] = cnf->disable_policy;
 	array[DEVCONF_NDISC_TCLASS] = cnf->ndisc_tclass;
+	array[DEVCONF_RPL_SEG_ENABLED] = cnf->rpl_seg_enabled;
 }
 
 static inline size_t inet6_ifla6_size(void)
@@ -6850,6 +6904,13 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.extra2		= (void *)&two_five_five,
 	},
 	{
+		.procname	= "rpl_seg_enabled",
+		.data		= &ipv6_devconf.rpl_seg_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
 		/* sentinel */
 	}
 };