router: advertise removed addresses as invalid in 3 consecutive RAs

[project/odhcpd.git] / src / netlink.c

diff --git a/src/netlink.c b/src/netlink.c
index 39f6245ec82d35bbd8c9a2d371a4d8cbfe4a789b..63a0f8bd1f411ca579f8463612625bea662e03ad 100644 (file)
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -205,10 +205,66 @@ static void refresh_iface_addr6(int ifindex)
                        change = len != (ssize_t)iface->addr6_len;
                        for (ssize_t i = 0; !change && i < len; ++i) {
                                if (!IN6_ARE_ADDR_EQUAL(&addr[i].addr.in6, &iface->addr6[i].addr.in6) ||
+                                   addr[i].prefix != iface->addr6[i].prefix ||
                                    (addr[i].preferred > (uint32_t)now) != (iface->addr6[i].preferred > (uint32_t)now) ||
                                    addr[i].valid < iface->addr6[i].valid || addr[i].preferred < iface->addr6[i].preferred)
                                        change = true;
                        }
+
+                       if (change) {
+                               /*
+                                * Keep track on removed prefixes, so we could advertise them as invalid
+                                * for at least a couple of times.
+                                *
+                                * RFC7084 § 4.3 :
+                                *    L-13:  If the delegated prefix changes, i.e., the current prefix is
+                                *           replaced with a new prefix without any overlapping time
+                                *           period, then the IPv6 CE router MUST immediately advertise the
+                                *           old prefix with a Preferred Lifetime of zero and a Valid
+                                *           Lifetime of either a) zero or b) the lower of the current
+                                *           Valid Lifetime and two hours (which must be decremented in
+                                *           real time) in a Router Advertisement message as described in
+                                *           Section 5.5.3, (e) of [RFC4862].
+                                */
+
+                               for (size_t i = 0; i < iface->addr6_len; ++i) {
+                                       bool removed = true;
+
+                                       if (iface->addr6[i].valid <= (uint32_t)now)
+                                               continue;
+
+                                       for (ssize_t j = 0; removed && j < len; ++j) {
+                                               size_t plen = min(addr[j].prefix, iface->addr6[i].prefix);
+
+                                               if (odhcpd_bmemcmp(&addr[j].addr.in6, &iface->addr6[i].addr.in6, plen) == 0)
+                                                       removed = false;
+                                       }
+
+                                       for (size_t j = 0; removed && j < iface->invalid_addr6_len; ++j) {
+                                               size_t plen = min(iface->invalid_addr6[j].prefix, iface->addr6[i].prefix);
+
+                                               if (odhcpd_bmemcmp(&iface->invalid_addr6[j].addr.in6, &iface->addr6[i].addr.in6, plen) == 0)
+                                                       removed = false;
+                                       }
+
+                                       if (removed) {
+                                               size_t pos = iface->invalid_addr6_len;
+                                               struct odhcpd_ipaddr *new_invalid_addr6 = realloc(iface->invalid_addr6,
+                                                               sizeof(*iface->invalid_addr6) * (pos + 1));
+
+                                               if (!new_invalid_addr6)
+                                                       break;
+
+                                               iface->invalid_addr6 = new_invalid_addr6;
+                                               iface->invalid_addr6_len++;
+                                               memcpy(&iface->invalid_addr6[pos], &iface->addr6[i], sizeof(*iface->invalid_addr6));
+                                               iface->invalid_addr6[pos].valid = iface->invalid_addr6[pos].preferred = (uint32_t)now;
+
+                                               if (iface->invalid_addr6[pos].prefix < 64)
+                                                       iface->invalid_addr6[pos].prefix = 64;
+                                       }
+                               }
+                       }
                }
 
                iface->addr6 = addr;