Darwin: add NetworkIOMeter support

darwin/Platform.c

@@ -14,6 +14,10 @@ in the source distribution for its full text.
 #include <math.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <net/if.h>
+#include <net/if_types.h>
+#include <net/route.h>
+#include <sys/socket.h>
 #include <sys/_types/_mach_port_t.h>
 
 #include <CoreFoundation/CFBase.h>
@@ -138,6 +142,7 @@ const MeterClass* const Platform_meterTypes[] = {
    &ZfsArcMeter_class,
    &ZfsCompressedArcMeter_class,
    &DiskIOMeter_class,
+   &NetworkIOMeter_class,
    &FileDescriptorMeter_class,
    &BlankMeter_class,
    NULL
@@ -464,10 +469,65 @@ bool Platform_getDiskIO(DiskIOData* data) {
    return true;
 }
 
+/* Caution: Given that interfaces are dynamic, and it is not possible to get statistics on interfaces that no longer exist,
+   if some interface disappears between the time of two samples, the values of the second sample may be lower than those of
+   the first one. */
 bool Platform_getNetworkIO(NetworkIOData* data) {
-   // TODO
-   (void)data;
-   return false;
+   int mib[6] = {CTL_NET,
+      PF_ROUTE, /* routing messages */
+      0, /* protocal number, currently always 0 */
+      0, /* select all address families */
+      NET_RT_IFLIST2, /* interface list with addresses */
+      0};
+
+   for (size_t retry = 0; retry < 4; retry++) {
+      size_t len = 0;
+
+      /* Determine len */
+      if (sysctl(mib, ARRAYSIZE(mib), NULL, &len, NULL, 0) < 0 || len == 0)
+         return false;
+
+      len += 16 * retry * retry * sizeof(struct if_msghdr2);
+      char *buf = xMalloc(len);
+
+      if (sysctl(mib, ARRAYSIZE(mib), buf, &len, NULL, 0) < 0) {
+         free(buf);
+         if (errno == ENOMEM && retry < 3)
+            continue;
+         else
+            return false;
+      }
+
+      uint64_t bytesReceived_sum = 0, packetsReceived_sum = 0, bytesTransmitted_sum = 0, packetsTransmitted_sum = 0;
+
+      for (char *next = buf; next < buf + len;) {
+         void *tmp = (void*) next;
+         struct if_msghdr *ifm = (struct if_msghdr*) tmp;
+
+         next += ifm->ifm_msglen;
+
+         if (ifm->ifm_type != RTM_IFINFO2)
+            continue;
+
+         struct if_msghdr2 *ifm2 = (struct if_msghdr2*) ifm;
+
+         if (ifm2->ifm_data.ifi_type != IFT_LOOP) { /* do not count loopback traffic */
+            bytesReceived_sum += ifm2->ifm_data.ifi_ibytes;
+            packetsReceived_sum += ifm2->ifm_data.ifi_ipackets;
+            bytesTransmitted_sum += ifm2->ifm_data.ifi_obytes;
+            packetsTransmitted_sum += ifm2->ifm_data.ifi_opackets;
+         }
+      }
+
+      data->bytesReceived = bytesReceived_sum;
+      data->packetsReceived = packetsReceived_sum;
+      data->bytesTransmitted = bytesTransmitted_sum;
+      data->packetsTransmitted = packetsTransmitted_sum;
+
+      free(buf);
+   }
+
+   return true;
 }
 
 void Platform_getBattery(double* percent, ACPresence* isOnAC) {