Sample code for network interface settings

//--------------------------------------------------------------------------------------------------
//--------------------------------------------------------------------------------------------------
static void SetNetworkConfiguration
(
    le_mdc_ProfileRef_t profileRef
)
{
    char ipAddr[100] = {0};
    char gatewayAddr[100] = {0};
    char dns1Addr[100] = {0};
    char dns2Addr[100] = {0};
    char systemCmd[200] = {0};
    FILE* resolvFilePtr;
    le_mdc_ConState_t state = LE_MDC_DISCONNECTED;
    mode_t oldMask;

    // Check the state
    LE_ASSERT( le_mdc_GetSessionState(profileRef, &state) == LE_OK );
    LE_ASSERT( state == LE_MDC_CONNECTED );

    // Get IP, gateway and DNS addresses for IPv4 or IPv6 connectivity
    if ( le_mdc_IsIPv4(profileRef) )
    {
        LE_ASSERT(le_mdc_GetIPv4Address(profileRef, ipAddr, sizeof(ipAddr)) == LE_OK);
        LE_PRINT_VALUE("%s", ipAddr);

        LE_ASSERT(le_mdc_GetIPv4GatewayAddress(profileRef, gatewayAddr, sizeof(gatewayAddr))
                                                                                          == LE_OK);
        LE_PRINT_VALUE("%s", gatewayAddr);

        LE_ASSERT(le_mdc_GetIPv4DNSAddresses( profileRef,
                                              dns1Addr, sizeof(dns1Addr),
                                              dns2Addr, sizeof(dns2Addr)) == LE_OK );
        LE_PRINT_VALUE("%s", dns1Addr);
        LE_PRINT_VALUE("%s", dns2Addr);

        snprintf(systemCmd, sizeof(systemCmd), "/sbin/route add default gw %s", gatewayAddr);
    }
    else if ( le_mdc_IsIPv6(profileRef) )
    {
        LE_ASSERT(le_mdc_GetIPv6Address(profileRef, ipAddr, sizeof(ipAddr)) == LE_OK);
        LE_PRINT_VALUE("%s", ipAddr);

        LE_ASSERT(le_mdc_GetIPv6GatewayAddress(profileRef, gatewayAddr, sizeof(gatewayAddr))
                                                                                          == LE_OK);
        LE_PRINT_VALUE("%s", gatewayAddr);

        LE_ASSERT(le_mdc_GetIPv6DNSAddresses( profileRef,
                                              dns1Addr, sizeof(dns1Addr),
                                              dns2Addr, sizeof(dns2Addr)) == LE_OK );
        LE_PRINT_VALUE("%s", dns1Addr);
        LE_PRINT_VALUE("%s", dns2Addr);

        snprintf(systemCmd, sizeof(systemCmd), "/sbin/route -A inet6 add default gw %s",
                                                gatewayAddr);
    }

    sleep(5);

    LE_DEBUG("%s", systemCmd);
    LE_ASSERT( system(systemCmd) == 0 );

    // allow fopen to create file with mode=644
    oldMask = umask(022);

    // open the resolver configuration
    resolvFilePtr = fopen("/etc/resolv.conf", "w+");

    if (resolvFilePtr == NULL)
    {
        LE_ERROR("Unable to open resolv.conf: %m");
    }
    LE_ASSERT( resolvFilePtr != NULL );

    LE_ASSERT( fprintf(resolvFilePtr, "nameserver %s\n", dns1Addr) > 0 );

    if (dns2Addr[0] != '\0')
    {
        LE_ASSERT( fprintf(resolvFilePtr, "nameserver %s\n", dns2Addr) > 0 );
    }

    LE_ASSERT( fclose(resolvFilePtr) == 0 );

    // restore old mask
    umask(oldMask);
}