Dynamically calculate RA intervals when prefix lifetimes are short

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

diff --git a/src/router.c b/src/router.c
index 9258acf..372c400 100644 (file)
--- a/src/router.c
+++ b/src/router.c
@@ -130,12 +130,50 @@ static void sigusr1_refresh(_unused int signal)
                        uloop_timeout_set(&iface->timer_rs, 1000);
 }
 
+static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size_t len)
+{
+       struct icmp6_hdr *hdr = (struct icmp6_hdr *)data;
+       struct icmpv6_opt *opt, *end = (struct icmpv6_opt*)&data[len];
+
+       /* Hoplimit is already checked in odhcpd_receive_packets */
+       if (len < sizeof(*hdr) || hdr->icmp6_code)
+               return false;
+
+       switch (hdr->icmp6_type) {
+       case ND_ROUTER_ADVERT:
+               if (!IN6_IS_ADDR_LINKLOCAL(&source->sin6_addr))
+                       return false;
+
+               opt = (struct icmpv6_opt *)((struct nd_router_advert *)data + 1);
+               break;
+
+       case ND_ROUTER_SOLICIT:
+               opt = (struct icmpv6_opt *)((struct nd_router_solicit *)data + 1);
+               break;
+
+       default:
+               return false;
+       }
+
+       icmpv6_for_each_option(opt, opt, end)
+               if (opt->type == ND_OPT_SOURCE_LINKADDR &&
+                               IN6_IS_ADDR_UNSPECIFIED(&source->sin6_addr) &&
+                               hdr->icmp6_type == ND_ROUTER_SOLICIT)
+                       return false;
+
+       // Check all options parsed successfully
+       return opt == end;
+}
 
 // Event handler for incoming ICMPv6 packets
-static void handle_icmpv6(_unused void *addr, void *data, size_t len,
+static void handle_icmpv6(void *addr, void *data, size_t len,
                struct interface *iface)
 {
        struct icmp6_hdr *hdr = data;
+
+       if (!router_icmpv6_valid(addr, data, len))
+               return;
+
        if ((iface->ra == RELAYD_SERVER && !iface->master)) { // Server mode
                if (hdr->icmp6_type == ND_ROUTER_SOLICIT)
                        send_router_advert(&iface->timer_rs);
@@ -169,7 +207,7 @@ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 
        char line[512], ifname[16];
        bool found_default = false;
-       struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, 0, 0};
+       struct odhcpd_ipaddr p = {IN6ADDR_ANY_INIT, 0, false, 0, 0, 0};
        while (fgets(line, sizeof(line), fp_route)) {
                uint32_t rflags;
                if (sscanf(line, "00000000000000000000000000000000 00 "
@@ -219,7 +257,10 @@ static void send_router_advert(struct uloop_timeout *event)
                .lladdr = {ND_OPT_SOURCE_LINKADDR, 1, {0}},
                .mtu = {ND_OPT_MTU, 1, 0, htonl(mtu)},
        };
-       adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
+
+       if (iface->dhcpv6)
+               adv.h.nd_ra_flags_reserved = ND_RA_FLAG_OTHER;
+
        if (iface->managed >= RELAYD_MANAGED_MFLAG)
                adv.h.nd_ra_flags_reserved |= ND_RA_FLAG_MANAGED;
 
@@ -232,6 +273,7 @@ static void send_router_advert(struct uloop_timeout *event)
        // If not currently shutting down
        struct odhcpd_ipaddr addrs[RELAYD_MAX_PREFIXES];
        ssize_t ipcnt = 0;
+       uint64_t maxpreferred = 0;
 
        // If not shutdown
        if (event->cb) {
@@ -254,7 +296,7 @@ static void send_router_advert(struct uloop_timeout *event)
 
        for (ssize_t i = 0; i < ipcnt; ++i) {
                struct odhcpd_ipaddr *addr = &addrs[i];
-               if (addr->prefix > 64)
+               if (addr->prefix > 64 || addr->has_class)
                        continue; // Address not suitable
 
                if (addr->preferred > MaxPreferredTime)
@@ -277,9 +319,13 @@ static void send_router_advert(struct uloop_timeout *event)
                        p = &adv.prefix[cnt++];
                }
 
-               if ((addr->addr.s6_addr[0] & 0xfe) != 0xfc && addr->preferred > 0)
+               if ((addr->addr.s6_addr[0] & 0xfe) != 0xfc && addr->preferred > 0) {
                        have_public = true;
 
+                       if (maxpreferred < 1000 * addr->preferred)
+                               maxpreferred = 1000 * addr->preferred;
+               }
+
                memcpy(&p->nd_opt_pi_prefix, &addr->addr, 8);
                p->nd_opt_pi_type = ND_OPT_PREFIX_INFORMATION;
                p->nd_opt_pi_len = 4;
@@ -304,11 +350,6 @@ static void send_router_advert(struct uloop_timeout *event)
                adv.h.nd_ra_router_lifetime = 0;
        }
 
-       if (have_public && iface->deprecate_ula_if_public_avail)
-               for (size_t i = 0; i < cnt; ++i)
-                       if ((adv.prefix[i].nd_opt_pi_prefix.s6_addr[0] & 0xfe) == 0xfc)
-                               adv.prefix[i].nd_opt_pi_preferred_time = 0;
-
        // DNS Recursive DNS
        if (iface->dns_cnt > 0) {
                dns_addr = iface->dns;
@@ -353,6 +394,11 @@ static void send_router_advert(struct uloop_timeout *event)
                uint32_t lifetime;
                uint8_t name[];
        } *search = alloca(sizeof(*search) + search_padded);
+
+       if (!search) {
+               syslog(LOG_ERR, "Alloca failed for dns search on interface %s", iface->ifname);
+               return;
+       }
        search->type = ND_OPT_DNS_SEARCH;
        search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
        search->pad = 0;
@@ -410,12 +456,27 @@ static void send_router_advert(struct uloop_timeout *event)
        odhcpd_send(router_event.uloop.fd,
                        &all_nodes, iov, ARRAY_SIZE(iov), iface);
 
-       // Rearm timer
-       int msecs;
-       odhcpd_urandom(&msecs, sizeof(msecs));
-       msecs = (labs(msecs) % (1000 * (MaxRtrAdvInterval
-                       - MinRtrAdvInterval))) + (MinRtrAdvInterval * 1000);
-       uloop_timeout_set(&iface->timer_rs, msecs);
+       // Rearm timer if not shut down
+       if (event->cb) {
+               uint32_t maxinterval = MaxRtrAdvInterval * 1000;
+               uint32_t mininterval = MinRtrAdvInterval * 1000;
+
+               if (maxpreferred > 0 && maxinterval > maxpreferred / 2) {
+                       maxinterval = maxpreferred / 2;
+                       if (maxinterval < 4000)
+                               maxinterval = 4000;
+
+                       if (maxinterval >= 9000)
+                               mininterval = maxinterval / 3;
+                       else
+                               mininterval = (maxinterval * 3) / 4;
+               }
+
+               int msecs;
+               odhcpd_urandom(&msecs, sizeof(msecs));
+               msecs = (labs(msecs) % (maxinterval - mininterval)) + mininterval;
+               uloop_timeout_set(&iface->timer_rs, msecs);
+       }
 }