# HG changeset patch
# Parent  cb2ea88a7a426fb93e3c781fbc146126e574a9de

diff --git a/core/proto.c b/core/proto.c
--- a/core/proto.c
+++ b/core/proto.c
@@ -202,11 +202,13 @@
         struct lgtd_lifx_bulb *bulb = device->device;
 
         char buf[2048],
+             gw_addr[LGTD_LIFX_ADDR_STRLEN],
              site_addr[LGTD_LIFX_ADDR_STRLEN],
              bulb_addr[LGTD_LIFX_ADDR_STRLEN];
         int i = 0;
 
         LGTD_IEEE8023MACTOA(bulb->addr, bulb_addr);
+        LGTD_IEEE8023MACTOA(bulb->gw->addr, gw_addr);
         LGTD_IEEE8023MACTOA(bulb->gw->site.as_array, site_addr);
 
         LGTD_SNPRINTF_APPEND(
@@ -215,11 +217,12 @@
                 "\"_lifx\":{"
                     "\"addr\": \"%s\","
                     "\"gateway\":{"
+                        "\"addr\":\"%s\","
                         "\"site\":\"%s\","
                         "\"url\":\"tcp://[%s]:%hu\","
                         "\"latency\":%ju"
                     "},",
-            bulb_addr, site_addr,
+            bulb_addr, gw_addr, site_addr,
             bulb->gw->ip_addr, bulb->gw->port,
             (uintmax_t)LGTD_LIFX_GATEWAY_LATENCY(bulb->gw)
         );
diff --git a/lifx/gateway.c b/lifx/gateway.c
--- a/lifx/gateway.c
+++ b/lifx/gateway.c
@@ -15,12 +15,15 @@
 // You should have received a copy of the GNU General Public License
 // along with lighstd.  If not, see <http://www.gnu.org/licenses/>.
 
+#include <sys/ioctl.h>
 #include <sys/queue.h>
+#include <sys/socket.h>
 #include <sys/tree.h>
 #include <assert.h>
 #include <endian.h>
 #include <err.h>
 #include <errno.h>
+#include <net/if_arp.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -279,6 +282,28 @@
     return bulb;
 }
 
+// TODO: make a separate shared library to resolve ip addresses to mac
+// addresses:
+static bool
+lgtd_lifx_gateway_resolve_ipv4_addr(int socket,
+                                    const struct sockaddr_in *sin,
+                                    uint8_t *hw_addr)
+{
+    assert(sin);
+    assert(hw_addr);
+    assert(socket >= 0);
+
+    struct arpreq req;
+    memset(&req, 0, sizeof(req));
+    memcpy(&req.arp_pa, sin, sizeof(*sin));
+    memcpy(req.arp_dev, "br0", 4);
+    if (!ioctl(socket, SIOCGARP, &req)) {
+        memcpy(hw_addr, req.arp_ha.sa_data, LGTD_LIFX_ADDR_LENGTH);
+        return true;
+    }
+    return false;
+}
+
 struct lgtd_lifx_gateway *
 lgtd_lifx_gateway_open(const struct sockaddr_storage *peer,
                        ev_socklen_t addrlen,
@@ -314,10 +339,20 @@
     gw->refresh_ev = evtimer_new(
         lgtd_ev_base, lgtd_lifx_gateway_refresh_callback, gw
     );
+
     memcpy(&gw->peer, peer, sizeof(gw->peer));
     lgtd_sockaddrtoa(peer, gw->ip_addr, sizeof(gw->ip_addr));
     gw->port = lgtd_sockaddrport(peer);
     memcpy(gw->site.as_array, site, sizeof(gw->site.as_array));
+    if (peer->ss_family == AF_INET) {
+        bool ok = lgtd_lifx_gateway_resolve_ipv4_addr(
+            gw->socket, (const struct sockaddr_in *)peer, gw->addr
+        );
+        if (!ok) {
+            lgtd_warn("couldn't resolve %s to a LIFX address", gw->ip_addr);
+        }
+    }
+
     gw->last_req_at = received_at;
     gw->next_req_at = received_at;
     gw->last_pkt_at = received_at;
@@ -332,11 +367,11 @@
         goto error_allocate;
     }
 
-    char site_addr[LGTD_LIFX_ADDR_STRLEN];
+    char site_addr[LGTD_LIFX_ADDR_STRLEN], addr[LGTD_LIFX_ADDR_STRLEN];
     lgtd_info(
-        "gateway for site %s at [%s]:%hu",
+        "gateway for site %s at [%s]:%hu (%s)",
         LGTD_IEEE8023MACTOA(gw->site.as_array, site_addr),
-        gw->ip_addr, gw->port
+        gw->ip_addr, gw->port, LGTD_IEEE8023MACTOA(gw->addr, addr)
     );
     LIST_INSERT_HEAD(&lgtd_lifx_gateways, gw, link);