router: unicast RAs to RS senders by default

diff --git a/src/router.c b/src/router.c
index a45a8cbbe2d176ed4ed71a587f9107cdebfb8154..77972ab210ab705197f0fcefac637578c3b9dfaf 100644 (file)
--- a/src/router.c
+++ b/src/router.c
@@ -31,7 +31,7 @@ static void forward_router_advertisement(uint8_t *data, size_t len);
 
 static void handle_icmpv6(void *addr, void *data, size_t len,
                struct interface *iface, void *dest);
-static void send_router_advert(struct uloop_timeout *event);
+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};
@@ -104,7 +104,7 @@ int setup_router_interface(struct interface *iface, bool enable)
 
        if (!enable) {
                if (iface->ra)
-                       send_router_advert(&iface->timer_rs);
+                       trigger_router_advert(&iface->timer_rs);
        } else {
                void *mreq = &all_routers;
 
@@ -112,8 +112,8 @@ int setup_router_interface(struct interface *iface, bool enable)
                        mreq = &all_nodes;
                        forward_router_solicitation(iface);
                } else if (iface->ra == RELAYD_SERVER && !iface->master) {
-                       iface->timer_rs.cb = send_router_advert;
-                       send_router_advert(&iface->timer_rs);
+                       iface->timer_rs.cb = trigger_router_advert;
+                       trigger_router_advert(&iface->timer_rs);
                }
 
                if (iface->ra == RELAYD_RELAY || (iface->ra == RELAYD_SERVER && !iface->master))
@@ -168,26 +168,6 @@ static bool router_icmpv6_valid(struct sockaddr_in6 *source, uint8_t *data, size
        return opt == end;
 }
 
-// Event handler for incoming ICMPv6 packets
-static void handle_icmpv6(void *addr, void *data, size_t len,
-               struct interface *iface, _unused void *dest)
-{
-       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);
-       } else if (iface->ra == RELAYD_RELAY) { // Relay mode
-               if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
-                       forward_router_advertisement(data, len);
-               else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
-                       forward_router_solicitation(odhcpd_get_master_interface());
-       }
-}
-
 
 // Detect whether a default route exists, also find the source prefixes
 static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
@@ -227,11 +207,8 @@ static bool parse_routes(struct odhcpd_ipaddr *n, ssize_t len)
 
 
 // Router Advert server mode
-static void send_router_advert(struct uloop_timeout *event)
+static uint64_t send_router_advert(struct interface *iface, const struct in6_addr *from)
 {
-       struct interface *iface =
-                       container_of(event, struct interface, timer_rs);
-
        int mtu = odhcpd_get_interface_mtu(iface->ifname);
        if (mtu < 0)
                mtu = 1500;
@@ -265,7 +242,7 @@ static void send_router_advert(struct uloop_timeout *event)
        uint64_t maxpreferred = 0;
 
        // If not shutdown
-       if (event->cb) {
+       if (iface->timer_rs.cb) {
                ipcnt = odhcpd_get_interface_addresses(iface->ifindex,
                                addrs, ARRAY_SIZE(addrs));
 
@@ -385,10 +362,6 @@ static void send_router_advert(struct uloop_timeout *event)
                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;
@@ -443,9 +416,22 @@ static void send_router_advert(struct uloop_timeout *event)
                        {&dns, (dns_cnt) ? sizeof(dns) : 0},
                        {dns_addr, dns_cnt * sizeof(*dns_addr)},
                        {search, search->len * 8}};
-       struct sockaddr_in6 all_nodes = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
+       struct sockaddr_in6 dest = {AF_INET6, 0, 0, ALL_IPV6_NODES, 0};
+
+       if (from && !IN6_IS_ADDR_UNSPECIFIED(from))
+               dest.sin6_addr = *from;
+
        odhcpd_send(router_event.uloop.fd,
-                       &all_nodes, iov, ARRAY_SIZE(iov), iface);
+                       &dest, iov, ARRAY_SIZE(iov), iface);
+
+       return maxpreferred;
+}
+
+
+static void trigger_router_advert(struct uloop_timeout *event)
+{
+       struct interface *iface = container_of(event, struct interface, timer_rs);
+       uint64_t maxpreferred = send_router_advert(iface, NULL);
 
        // Rearm timer if not shut down
        if (event->cb) {
@@ -466,7 +452,29 @@ static void send_router_advert(struct uloop_timeout *event)
                int msecs;
                odhcpd_urandom(&msecs, sizeof(msecs));
                msecs = (labs(msecs) % (maxinterval - mininterval)) + mininterval;
-               uloop_timeout_set(&iface->timer_rs, msecs);
+               uloop_timeout_set(event, msecs);
+       }
+}
+
+
+// Event handler for incoming ICMPv6 packets
+static void handle_icmpv6(void *addr, void *data, size_t len,
+               struct interface *iface, _unused void *dest)
+{
+       struct icmp6_hdr *hdr = data;
+       struct sockaddr_in6 *from = addr;
+
+       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, &from->sin6_addr);
+       } else if (iface->ra == RELAYD_RELAY) { // Relay mode
+               if (hdr->icmp6_type == ND_ROUTER_ADVERT && iface->master)
+                       forward_router_advertisement(data, len);
+               else if (hdr->icmp6_type == ND_ROUTER_SOLICIT && !iface->master)
+                       forward_router_solicitation(odhcpd_get_master_interface());
        }
 }