/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This file contains utility Objective-C code used by the SimpleTunnel server.

*/

@import Foundation;

@import Darwin;

#import <net/if_utun.h>

#import "tunnel_server-Bridging-Header.h"

UInt32

getUTUNControlIdentifier(int socket)

{

    struct ctl_info kernelControlInfo;

    bzero(&kernelControlInfo, sizeof(kernelControlInfo));

    strlcpy(kernelControlInfo.ctl_name, UTUN_CONTROL_NAME, sizeof(kernelControlInfo.ctl_name));

    if (ioctl(socket, CTLIOCGINFO, &kernelControlInfo)) {

        printf("ioctl failed on kernel control socket: %s\n", strerror(errno));

        return 0;

    }

    return kernelControlInfo.ctl_id;

}

BOOL

setSocketNonBlocking(int socket)

{

    int currentFlags = fcntl(socket, F_GETFL);

    if (currentFlags < 0) {

        printf("fcntl(F_GETFL) failed: %s\n", strerror(errno));

        return NO;

    }

    currentFlags |= O_NONBLOCK;

    if (fcntl(socket, F_SETFL, currentFlags) < 0) {

        printf("fcntl(F_SETFL) failed: %s\n", strerror(errno));

        return NO;

    }

    return YES;

}

BOOL

setUTUNAddress(NSString *interfaceName, NSString *addressString)

{

    struct in_addr address;

    if (inet_pton(AF_INET, [addressString UTF8String], &address) == 1) {

        struct ifaliasreq interfaceAliasRequest __attribute__ ((aligned (4)));

        struct in_addr mask = { 0xffffffff };

        int socketDescriptor = socket(AF_INET, SOCK_DGRAM, 0);

        if (socketDescriptor < 0) {

            printf("Failed to create a DGRAM socket: %s\n", strerror(errno));

            return NO;

        }

        memset(&interfaceAliasRequest, 0, sizeof(interfaceAliasRequest));

        strlcpy(interfaceAliasRequest.ifra_name, [interfaceName UTF8String], sizeof(interfaceAliasRequest.ifra_name));

        interfaceAliasRequest.ifra_addr.sa_family = AF_INET;

        interfaceAliasRequest.ifra_addr.sa_len = sizeof(struct sockaddr_in);

        memcpy(&((struct sockaddr_in *)&interfaceAliasRequest.ifra_addr)->sin_addr, &address, sizeof(address));

        interfaceAliasRequest.ifra_broadaddr.sa_family = AF_INET;

        interfaceAliasRequest.ifra_broadaddr.sa_len = sizeof(struct sockaddr_in);

        memcpy(&((struct sockaddr_in *)&interfaceAliasRequest.ifra_broadaddr)->sin_addr, &address, sizeof(address));

        interfaceAliasRequest.ifra_mask.sa_family = AF_INET;

        interfaceAliasRequest.ifra_mask.sa_len = sizeof(struct sockaddr_in);

        memcpy(&((struct sockaddr_in *)&interfaceAliasRequest.ifra_mask)->sin_addr, &mask, sizeof(mask));

        if (ioctl(socketDescriptor, SIOCAIFADDR, &interfaceAliasRequest) < 0) {

            printf("Failed to set the address of %s interface address to %s: %s\n", [interfaceName UTF8String], [addressString UTF8String], strerror(errno));

            close(socketDescriptor);

            return NO;

        }

        close(socketDescriptor);

    }

    return YES;

}

int

getUTUNNameOption(void)

{

    return UTUN_OPT_IFNAME;

}