router: don't announce prefixes with valid lifetime equal to 0
[project/odhcpd.git] / src / router.c
index 1a008e1..e8a9aa9 100644 (file)
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <stdbool.h>
+#include <arpa/inet.h>
 #include <net/route.h>
 
 #include "router.h"
@@ -34,11 +35,12 @@ 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};
+static struct odhcpd_event router_event = {.uloop = {.fd = -1}, .handle_dgram = handle_icmpv6, };
 
 static FILE *fp_route = NULL;
 #define RA_IOV_LEN 6
 
+#define TIME_LEFT(t1, now) ((t1) != UINT32_MAX ? (t1) - (now) : UINT32_MAX)
 
 int init_router(void)
 {
@@ -98,6 +100,9 @@ int setup_router_interface(struct interface *iface, bool enable)
        uloop_timeout_cancel(&iface->timer_rs);
        iface->timer_rs.cb = NULL;
 
+       if (iface->ifindex <= 0)
+               return -1;
+
        setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
                        &all_nodes, sizeof(all_nodes));
        setsockopt(router_event.uloop.fd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP,
@@ -206,6 +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)
 {
@@ -243,34 +291,48 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
        odhcpd_get_mac(iface, adv.lladdr.data);
 
        // If not currently shutting down
-       struct odhcpd_ipaddr *addrs = NULL;
+       struct odhcpd_ipaddr addrs[RELAYD_MAX_ADDRS];
        ssize_t ipcnt = 0;
-       int64_t minvalid = INT64_MAX;
-       int64_t maxvalid = 0;
+       uint32_t minvalid = UINT32_MAX;
+       bool default_route = false;
+       bool valid_prefix = false;
 
        // If not shutdown
        if (iface->timer_rs.cb) {
-               addrs = iface->ia_addr;
                ipcnt = iface->ia_addr_len;
+               memcpy(addrs, iface->ia_addr, ipcnt * sizeof(*addrs));
 
                // Check default route
-               if (parse_routes(addrs, ipcnt))
-                       adv.h.nd_ra_router_lifetime = htons(1);
-               if (iface->default_router > 1)
-                       adv.h.nd_ra_router_lifetime = htons(iface->default_router);
+               if (iface->default_router) {
+                       default_route = true;
+
+                       if (iface->default_router > 1)
+                               valid_prefix = true;
+               } else if (parse_routes(addrs, ipcnt))
+                       default_route = true;
        }
 
        // Construct Prefix Information options
        size_t cnt = 0;
 
-       struct in6_addr dns_pref = IN6ADDR_ANY_INIT, *dns_addr = &dns_pref;
-       uint32_t dns_time = 0;
+       struct in6_addr dns_pref, *dns_addr = &dns_pref;
        size_t dns_cnt = 1;
 
+       odhcpd_get_linklocal_interface_address(iface->ifindex, &dns_pref);
+
        for (ssize_t i = 0; i < ipcnt; ++i) {
                struct odhcpd_ipaddr *addr = &addrs[i];
-               if (addr->prefix > 96 || addr->valid <= (uint32_t)now)
-                       continue; // Address not suitable
+               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 as RA prefix on %s",
+                                       namebuf, addr->prefix, addr->valid, iface->ifname);
+                       continue;
+               }
 
                struct nd_opt_prefix_info *p = NULL;
                for (size_t i = 0; i < cnt; ++i) {
@@ -287,16 +349,23 @@ 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 * (addr->valid - now))
-                       minvalid = 1000LL * (addr->valid - now);
+               if (addr->preferred > (uint32_t)now) {
+                       preferred = TIME_LEFT(addr->preferred, now);
+
+                       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 (maxvalid < 1000LL * (addr->valid - now))
-                       maxvalid = 1000LL * (addr->valid - now);
+               if (minvalid > valid)
+                       minvalid = valid;
 
-               if (((addr->addr.s6_addr[0] & 0xfe) != 0xfc || iface->default_router)
-                               && ntohs(adv.h.nd_ra_router_lifetime) < addr->valid - now)
-                       adv.h.nd_ra_router_lifetime = htons(addr->valid - now);
+               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);
@@ -310,28 +379,31 @@ 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(addr->valid - now);
-               if (addr->preferred > (uint32_t)now)
-                       p->nd_opt_pi_preferred_time = htonl(addr->preferred - now);
-
-
-               if (addr->preferred - now > dns_time) {
-                       dns_time = addr->preferred - now;
-                       dns_pref = addr->addr;
-               }
+               p->nd_opt_pi_preferred_time = htonl(preferred);
+               p->nd_opt_pi_valid_time = htonl(valid);
        }
 
-       if (!iface->default_router && ntohs(adv.h.nd_ra_router_lifetime) == 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) {
                dns_addr = iface->dns;
                dns_cnt = iface->dns_cnt;
-               dns_time = 0;
        }
 
        if (!dns_addr || IN6_IS_ADDR_UNSPECIFIED(dns_addr))
@@ -343,7 +415,7 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                uint8_t pad;
                uint8_t pad2;
                uint32_t lifetime;
-       } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, htonl(dns_time)};
+       } dns = {ND_OPT_RECURSIVE_DNS, (1 + (2 * dns_cnt)), 0, 0, 0};
 
 
 
@@ -410,7 +482,7 @@ static uint64_t send_router_advert(struct interface *iface, const struct in6_add
                        routes[routes_cnt].flags |= ND_RA_PREF_LOW;
                else if (iface->route_preference > 0)
                        routes[routes_cnt].flags |= ND_RA_PREF_HIGH;
-               routes[routes_cnt].lifetime = htonl(addr->valid - now);
+               routes[routes_cnt].lifetime = htonl(TIME_LEFT(addr->valid, now));
                routes[routes_cnt].addr[0] = addr->addr.s6_addr32[0];
                routes[routes_cnt].addr[1] = addr->addr.s6_addr32[1];
                routes[routes_cnt].addr[2] = 0;
@@ -419,35 +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(maxvalid / 1000);
-
-       if (!dns.lifetime)
-               dns.lifetime = search->lifetime;
-
-       odhcpd_urandom(&msecs, sizeof(msecs));
-       msecs = (labs(msecs) % (maxival - minival)) + minival;
+       search->lifetime = htonl(maxival*10);
+       dns.lifetime = search->lifetime;
 
        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] = {
@@ -566,7 +616,7 @@ static void forward_router_advertisement(uint8_t *data, size_t len)
                        size_t rewrite_cnt = iface->dns_cnt;
 
                        if (rewrite_cnt == 0) {
-                               if (odhcpd_get_preferred_interface_address(iface->ifindex, &addr) < 1)
+                               if (odhcpd_get_linklocal_interface_address(iface->ifindex, &addr))
                                        continue; // Unable to comply
 
                                rewrite = &addr;