From f37c6059363403d528acf8d530bb6e8a5666a875 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Fri, 27 Mar 2020 18:00:19 -0400 Subject: addrconf: add functionality to check on rpl requirements This patch adds a functionality to addrconf to check on a specific RPL address configuration. According to RFC 6554: 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. Signed-off-by: Alexander Aring Signed-off-by: David S. Miller --- net/ipv6/addrconf.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) (limited to 'net/ipv6/addrconf.c') 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 */ -- cgit v1.2.3-59-g8ed1b