iPhone Data Usage Tracking/Monitoring

The thing is that pdp_ip0 is one of interfaces, all pdpXXX are WWAN interfaces dedicated to different functions, voicemail, general networking interface.

I read in Apple forum that :
The OS does not keep network statistics on a process-by-process basis. As such, there’s no exact solution to this problem. You can, however, get network statistics for each network interface.

In general en0 is your Wi-Fi interface and pdp_ip0 is your WWAN interface.

There is no good way to get information wifi/cellular network data since, particular date-time!

Data statistic (ifa_data->ifi_obytes and ifa_data->ifi_ibytes) are stored from previous device reboot.

I don’t know why, but ifi_opackets and ifi_ipackets are shown just for lo0 (I think its main interface ).

Yes. Then device is connected via WiFi and doesn’t use internet if_iobytes values still come because this method provides network bytes exchanges and not just internet.

#include <net/if.h>
#include <ifaddrs.h>

static NSString *const DataCounterKeyWWANSent = @"WWANSent";
static NSString *const DataCounterKeyWWANReceived = @"WWANReceived";
static NSString *const DataCounterKeyWiFiSent = @"WiFiSent";
static NSString *const DataCounterKeyWiFiReceived = @"WiFiReceived";

NSDictionary *DataCounters()
{
    struct ifaddrs *addrs;
    const struct ifaddrs *cursor;

    u_int32_t WiFiSent = 0;
    u_int32_t WiFiReceived = 0;
    u_int32_t WWANSent = 0;
    u_int32_t WWANReceived = 0;

    if (getifaddrs(&addrs) == 0)
    {
        cursor = addrs;
        while (cursor != NULL)
        {
            if (cursor->ifa_addr->sa_family == AF_LINK)
            {
#ifdef DEBUG
                const struct if_data *ifa_data = (struct if_data *)cursor->ifa_data;
                if (ifa_data != NULL)
                {
                    NSLog(@"Interface name %s: sent %tu received %tu",cursor->ifa_name,ifa_data->ifi_obytes,ifa_data->ifi_ibytes);
                }
#endif

                // name of interfaces:
                // en0 is WiFi
                // pdp_ip0 is WWAN
                NSString *name = @(cursor->ifa_name);
                if ([name hasPrefix:@"en"])
                {
                    const struct if_data *ifa_data = (struct if_data *)cursor->ifa_data;
                    if (ifa_data != NULL)
                    {
                        WiFiSent += ifa_data->ifi_obytes;
                        WiFiReceived += ifa_data->ifi_ibytes;
                    }
                }

                if ([name hasPrefix:@"pdp_ip"])
                {
                    const struct if_data *ifa_data = (struct if_data *)cursor->ifa_data;
                    if (ifa_data != NULL)
                    {
                        WWANSent += ifa_data->ifi_obytes;
                        WWANReceived += ifa_data->ifi_ibytes;
                    }
                }
            }

            cursor = cursor->ifa_next;
        }

        freeifaddrs(addrs);
    }

    return @{DataCounterKeyWiFiSent : @(WiFiSent),
             DataCounterKeyWiFiReceived : @(WiFiReceived),
             DataCounterKeyWWANSent : @(WWANSent),
             DataCounterKeyWWANReceived : @(WWANReceived)};
}

Improved copy/paste support !