router: don't announce prefixes with valid lifetime equal to 0
[project/odhcpd.git] / src / router.c
index a09e107..e8a9aa9 100644 (file)
@@ -35,7 +35,7 @@ static void handle_icmpv6(void *addr, void *data, size_t len,
 static void trigger_router_advert(struct uloop_timeout *event);
 static void sigusr1_refresh(int signal);
 
-static struct odhcpd_event router_event = {{.fd = -1}, handle_icmpv6, NULL};
+static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
 
 static FILE *fp_route = NULL;
 #define RA_IOV_LEN 6
@@ -211,6 +211,49 @@ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
        return found_default;
 }
 
+static int calc_adv_interval(struct interface *iface, uint32_t minvalid,
+               uint32_t *maxival)
+{
+       uint32_t minival = iface->ra_mininterval;
+       int msecs;
+
+       *maxival = iface->ra_maxinterval;
+
+       if (*maxival > minvalid/3)
+               *maxival = minvalid/3;
+
+       if (*maxival > MaxRtrAdvInterval)
+               *maxival = MaxRtrAdvInterval;
+       else if (*maxival < 4)
+               *maxival = 4;
+
+       if (minival < MinRtrAdvInterval)
+               minival = MinRtrAdvInterval;
+       else if (minival > (*maxival * 3)/4)
+               minival = (*maxival >= 9 ? *maxival/3 : *maxival);
+
+       odhcpd_urandom(&msecs, sizeof(msecs));
+       msecs = (labs(msecs) % ((*maxival != minival) ? (*maxival - minival)*1000 : 500)) +
+                       minival*1000;
+
+       return msecs;
+}
+
+static uint16_t calc_ra_lifetime(struct interface *iface, uint32_t maxival)
+{
+       uint16_t lifetime = 3*maxival;
+
+       if (iface->ra_lifetime >= 0) {
+               lifetime = iface->ra_lifetime;
+               if (lifetime < maxival)
+                       lifetime = maxival;
+               else if (lifetime > 9000)
+                       lifetime = 9000;
+       }
+
+       return lifetime;
+}
+
 // Router Advert server mode
 static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
 {
@@ -250,7 +293,9 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
        // If not currently shutting down
        struct odhcpd_ipaddr addrs[RELAYD_MAX_ADDRS];
        ssize_t ipcnt = 0;
-       int64_t minvalid = INT64_MAX;
+       uint32_t minvalid = UINT32_MAX;
+       bool default_route = false;
+       bool valid_prefix = false;
 
        // If not shutdown
        if (iface->timer_rs.cb) {
@@ -258,13 +303,13 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                memcpy(addrs, iface->ia_addr, ipcnt * sizeof(*addrs));
 
                // Check default route
-               if (iface->default_router > 1)
-                       adv.h.nd_ra_router_lifetime = htons(iface->default_router);
-               else if (parse_routes(addrs, ipcnt))
-                       adv.h.nd_ra_router_lifetime = htons(1);
+               if (iface->default_router) {
+                       default_route = true;
 
-               syslog(LOG_INFO, "Initial router lifetime %d, %d address(es) available",
-                               ntohs(adv.h.nd_ra_router_lifetime), ipcnt);
+                       if (iface->default_router > 1)
+                               valid_prefix = true;
+               } else if (parse_routes(addrs, ipcnt))
+                       default_route = true;
        }
 
        // Construct Prefix Information options
@@ -277,13 +322,15 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
 
        for (ssize_t i = 0; i < ipcnt; ++i) {
                struct odhcpd_ipaddr *addr = &addrs[i];
+               uint32_t preferred = 0;
+               uint32_t valid = 0;
 
                if (addr->prefix > 96 || addr->valid <= (uint32_t)now) {
                        char namebuf[INET6_ADDRSTRLEN];
 
                        inet_ntop(AF_INET6, addr, namebuf, sizeof(namebuf));
-                       syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable",
-                                       namebuf, addr->prefix, addr->valid);
+                       syslog(LOG_INFO, "Address %s (prefix %d, valid %u) not suitable as RA prefix on %s",
+                                       namebuf, addr->prefix, addr->valid, iface->ifname);
                        continue;
                }
 
@@ -302,21 +349,24 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                        p = &adv.prefix[cnt++];
                }
 
-               if (addr->preferred > (uint32_t)now &&
-                               minvalid > 1000LL * TIME_LEFT(addr->valid, now))
-                       minvalid = 1000LL * TIME_LEFT(addr->valid, now);
+               if (addr->preferred > (uint32_t)now) {
+                       preferred = TIME_LEFT(addr->preferred, now);
 
-               uint32_t this_lifetime = TIME_LEFT(addr->valid, now);
-               if (this_lifetime > UINT16_MAX)
-                       this_lifetime = UINT16_MAX;
-               if (((addr->addr.s6_addr[0] & 0xfe) != 0xfc || iface->default_router)
-                               && adv.h.nd_ra_router_lifetime
-                               && ntohs(adv.h.nd_ra_router_lifetime) < this_lifetime) {
-                       adv.h.nd_ra_router_lifetime = htons(this_lifetime);
-
-                       syslog(LOG_DEBUG, "Updating router lifetime to %d", this_lifetime);
+                       if (iface->ra_useleasetime &&
+                                       preferred > iface->dhcpv4_leasetime)
+                               preferred = iface->dhcpv4_leasetime;
                }
 
+               valid = TIME_LEFT(addr->valid, now);
+               if (iface->ra_useleasetime && valid > iface->dhcpv4_leasetime)
+                       valid = iface->dhcpv4_leasetime;
+
+               if (minvalid > valid)
+                       minvalid = valid;
+
+               if (!IN6_IS_ADDR_ULA(&addr->addr) || iface->default_router)
+                       valid_prefix = true;
+
                odhcpd_bmemcpy(&p->nd_opt_pi_prefix, &addr->addr,
                                (iface->ra_advrouter) ? 128 : addr->prefix);
                p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
@@ -329,18 +379,26 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                        p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_AUTO;
                if (iface->ra_advrouter)
                        p->nd_opt_pi_flags_reserved |= ND_OPT_PI_FLAG_RADDR;
-               p->nd_opt_pi_valid_time = htonl(TIME_LEFT(addr->valid, now));
-               if (addr->preferred > (uint32_t)now)
-                       p->nd_opt_pi_preferred_time = htonl(TIME_LEFT(addr->preferred, now));
-               else if (addr->valid - now < 7200)
-                       p->nd_opt_pi_valid_time = 0;
+               p->nd_opt_pi_preferred_time = htonl(preferred);
+               p->nd_opt_pi_valid_time = htonl(valid);
        }
 
-       if (!iface->default_router && adv.h.nd_ra_router_lifetime == htons(1)) {
-               syslog(LOG_WARNING, "A default route is present but there is no public prefix "
-                               "on %s thus we don't announce a default route!", iface->ifname);
+       // Calculate periodic transmit
+       uint32_t maxival;
+       int msecs = calc_adv_interval(iface, minvalid, &maxival);
+
+       if (default_route) {
+               if (!valid_prefix) {
+                       syslog(LOG_WARNING, "A default route is present but there is no public prefix "
+                                       "on %s thus we don't announce a default route!", iface->ifname);
+                       adv.h.nd_ra_router_lifetime = 0;
+               } else
+                       adv.h.nd_ra_router_lifetime = htons(calc_ra_lifetime(iface, maxival));
+
+       } else
                adv.h.nd_ra_router_lifetime = 0;
-       }
+
+       syslog(LOG_INFO, "Using a RA lifetime of %d seconds on %s", ntohs(adv.h.nd_ra_router_lifetime), iface->ifname);
 
        // DNS Recursive DNS
        if (iface->dns_cnt > 0) {
@@ -433,33 +491,13 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                ++routes_cnt;
        }
 
-       // Calculate periodic transmit
-       int msecs = 0;
-       uint32_t maxival = iface->ra_maxinterval * 1000;
-       uint32_t minival;
-
-       if (maxival < 4000 || maxival > MaxRtrAdvInterval * 1000)
-               maxival = MaxRtrAdvInterval * 1000;
-
-       if (maxival > minvalid / 3) {
-               maxival = minvalid / 3;
-
-               if (maxival < 4000)
-                       maxival = 4000;
-       }
-
-       minival = (maxival * 3) / 4;
-
-       search->lifetime = htonl(maxival / 100);
+       search->lifetime = htonl(maxival*10);
        dns.lifetime = search->lifetime;
 
-       odhcpd_urandom(&msecs, sizeof(msecs));
-       msecs = (labs(msecs) % (maxival - minival)) + minival;
-
        struct icmpv6_opt adv_interval = {
                .type = ND_OPT_RTR_ADV_INTERVAL,
                .len = 1,
-               .data = {0, 0, maxival >> 24, maxival >> 16, maxival >> 8, maxival}
+               .data = {0, 0, (maxival*1000) >> 24, (maxival*1000) >> 16, (maxival*1000) >> 8, maxival*1000}
        };
 
        struct iovec iov[RA_IOV_LEN] = {