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-rw-r--r--include/net/addrconf.h3
-rw-r--r--net/ipv6/addrconf.c53
2 files changed, 56 insertions, 0 deletions
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index a088349dd94f..e0eabe58aa8b 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -90,6 +90,9 @@ int ipv6_chk_addr_and_flags(struct net *net, const struct in6_addr *addr,
int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr);
#endif
+int ipv6_chk_rpl_srh_loop(struct net *net, const struct in6_addr *segs,
+ unsigned char nsegs);
+
bool ipv6_chk_custom_prefix(const struct in6_addr *addr,
const unsigned int prefix_len,
struct net_device *dev);
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 5b9de773ce73..594963a7e1ec 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4398,6 +4398,59 @@ 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
*/