DPDK-工具脚本网卡与驱动绑定

0x01 缘由

    dpdk_nic_bind.py脚本功能，将网卡名称同dpdk支持的驱动进行绑定，直接修改相关参数来达到此目的。此脚本处理流程：解析参数、检测网卡、将对应的网卡与对应驱动绑定。

    脚本做了异常处理：防止断开ssh连接，避免将DPDK驱动绑定到管理网口上。

0x02 源码注释

    直接上源码目的，复习python和看如何手动绑定驱动。

import sysimport osimport getopt     #运行参数选项处理import subprocess #创建子进程from os.path import exists, abspath, dirname, basename#以太网设备类型ETHERNET_CLASS = "0200"##全局以太网设备字典，下标通过PCI地址来索引。其中的每个设备本身就是设备属性的字典devices = {}# 列出DPDK支持的驱动类型dpdk_drivers = ["igb_uio", "vfio-pci", "uio_pci_generic"]#命令行相关标识b_flag = Nonestatus_flag = Falseforce_flag = Falseargs = []def usage():    '''Print usage information for the program'''    argv0 = basename(sys.argv[0])    print("""Usage:------     %(argv0)s [options] DEVICE1 DEVICE2 ....where DEVICE1, DEVICE2 etc, are specified via PCI "domain:bus:slot.func" syntaxor "bus:slot.func" syntax. For devices bound to Linux kernel drivers, they mayalso be referred to by Linux interface name e.g. eth0, eth1, em0, em1, etc.Options:    --help, --usage:        Display usage information and quit    -s, --status:        Print the current status of all known network interfaces.        For each device, it displays the PCI domain, bus, slot and function,        along with a text description of the device. Depending upon whether the        device is being used by a kernel driver, the igb_uio driver, or no        driver, other relevant information will be displayed:        * the Linux interface name e.g. if=eth0        * the driver being used e.g. drv=igb_uio        * any suitable drivers not currently using that device            e.g. unused=igb_uio        NOTE: if this flag is passed along with a bind/unbind option, the        status display will always occur after the other operations have taken        place.    -b driver, --bind=driver:        Select the driver to use or \"none\" to unbind the device    -u, --unbind:        Unbind a device (Equivalent to \"-b none\")    --force:        By default, devices which are used by Linux - as indicated by having        routes in the routing table - cannot be modified. Using the --force        flag overrides this behavior, allowing active links to be forcibly        unbound.        WARNING: This can lead to loss of network connection and should be used        with caution.Examples:---------To display current device status:        %(argv0)s --statusTo bind eth1 from the current driver and move to use igb_uio        %(argv0)s --bind=igb_uio eth1To unbind 0000:01:00.0 from using any driver        %(argv0)s -u 0000:01:00.0To bind 0000:02:00.0 and 0000:02:00.1 to the ixgbe kernel driver        %(argv0)s -b ixgbe 02:00.0 02:00.1    """ % locals())  # replace items from local variables#locals() 和globals()，它们提供了基于字典的访问局部和全局变量的方式。#这与子进程模块中的check_output函数大致相同，该模块仅在python 2.7中可用。def check_output(args, stderr=None):    '''Run a command and capture its output'''    return subprocess.Popen(args, stdout=subprocess.PIPE,                            stderr=stderr).communicate()[0]#找对应的模块def find_module(mod):    '''find the .ko file for kernel module named mod.    Searches the $RTE_SDK/$RTE_TARGET directory, the kernel    modules directory and finally under the parent directory of    the script '''    # check $RTE_SDK/$RTE_TARGET directory    if 'RTE_SDK' in os.environ and 'RTE_TARGET' in os.environ:        path = "%s/%s/kmod/%s.ko" % (os.environ['RTE_SDK'],                                     os.environ['RTE_TARGET'], mod)        if exists(path):            return path    # check using depmod    try:        depmod_out = check_output(["modinfo", "-n", mod],                                  stderr=subprocess.STDOUT).lower()        if "error" not in depmod_out:            path = depmod_out.strip()            if exists(path):                return path    except:  # if modinfo can't find module, it fails, so continue        pass    # check for a copy based off current path    tools_dir = dirname(abspath(sys.argv[0]))    if (tools_dir.endswith("tools")):        base_dir = dirname(tools_dir)        find_out = check_output(["find", base_dir, "-name", mod + ".ko"])        if len(find_out) > 0:  # something matched            path = find_out.splitlines()[0]            if exists(path):                return path#检测模块，是否相关驱动已经加载了def check_modules():    '''Checks that igb_uio is loaded'''    global dpdk_drivers    # 特殊表达式生成一个模块列表，列表中为字典    mods = [{"Name": driver, "Found": False} for driver in dpdk_drivers]    # first check if module is loaded    try:        # Get list of sysfs modules (both built-in and dynamically loaded)        sysfs_path = '/sys/module/'        # Get the list of directories in sysfs_path 得到列表        sysfs_mods = [os.path.join(sysfs_path, o) for o                      in os.listdir(sysfs_path)                      if os.path.isdir(os.path.join(sysfs_path, o))]        # Extract the last element of '/sys/module/abc' in the array        sysfs_mods = [a.split('/')[-1] for a in sysfs_mods]        # special case for vfio_pci (module is named vfio-pci,        # but its .ko is named vfio_pci) 迭代sysfs_mods中        sysfs_mods = map(lambda a:                         a if a != 'vfio_pci' else 'vfio-pci', sysfs_mods)        for mod in mods:            if mod["Name"] in sysfs_mods:                mod["Found"] = True    except:        pass    # check if we have at least one loaded module    if True not in [mod["Found"] for mod in mods] and b_flag is not None:        if b_flag in dpdk_drivers:            print("Error - no supported modules(DPDK driver) are loaded")            sys.exit(1)        else:            print("Warning - no supported modules(DPDK driver) are loaded")    # change DPDK driver list to only contain drivers that are loaded    dpdk_drivers = [mod["Name"] for mod in mods if mod["Found"]]def has_driver(dev_id):    '''return true if a device is assigned to a driver. False otherwise'''    return "Driver_str" in devices[dev_id]#根据设备ID查找pci设备def get_pci_device_details(dev_id):    '''This function gets additional details for a PCI device'''    device = {}        #执行lspci -vmmks 03:00.0(dev_id)    extra_info = check_output(["lspci", "-vmmks", dev_id]).splitlines()    # parse lspci details    for line in extra_info:        if len(line) == 0:            continue        name, value = line.decode().split("\t", 1)        name = name.strip(":") + "_str"        device[name] = value    # check for a unix interface name    sys_path = "/sys/bus/pci/devices/%s/net/" % dev_id    if exists(sys_path):        device["Interface"] = ",".join(os.listdir(sys_path))    else:        device["Interface"] = ""    # check if a port is used for ssh connection    device["Ssh_if"] = False    device["Active"] = ""    return device#得到网卡的详细信息，放入一个字典中；key 为pci设备地址，值为对应的网卡信息def get_nic_details():    '''This function populates the "devices" dictionary. The keys used are    the pci addresses (domain:bus:slot.func). The values are themselves    dictionaries - one for each NIC.'''    global devices    global dpdk_drivers    # clear any old data    devices = {}    # first loop through and read details for all devices    # request machine readable format, with numeric IDs    dev = {}    dev_lines = check_output(["lspci", "-Dvmmn"]).splitlines()    for dev_line in dev_lines:        if (len(dev_line) == 0):            if dev["Class"] == ETHERNET_CLASS: #只有类型为以太网类型时才是我们要找的设备                # convert device and vendor ids to numbers, then add to global                dev["Vendor"] = int(dev["Vendor"], 16)                dev["Device"] = int(dev["Device"], 16)                # use dict to make copy of dev                devices[dev["Slot"]] = dict(dev)        else:            name, value = dev_line.decode().split("\t", 1) #以\t为分隔符分离字符串            dev[name.rstrip(":")] = value        #以上大概操作为 ["Slot"] = "0000:03:00.0"    # check what is the interface if any for an ssh connection if    # any to this host, so we can mark it later.     ssh_if = []    route = check_output(["ip", "-o", "route"])     #运行返回的路由信息如下：172.16.0.0/16 dev enp2s0  proto kernel  scope link  src 172.16.1.47  metric 100     # filter out all lines for 169.254 routes    route = "\n".join(filter(lambda ln: not ln.startswith("169.254"),                             route.decode().splitlines()))    #filter()函数是 Python 内置的另一个有用的高阶函数，filter()函数接收一个函数 f 和一个list，    #这个函数 f 的作用是对每个元素进行判断，返回 True或 False，filter()根据判断结果自动过滤    #掉不符合条件的元素，返回由符合条件元素组成的新list。    rt_info = route.split()    for i in range(len(rt_info) - 1):        if rt_info[i] == "dev":            ssh_if.append(rt_info[i+1])    # based on the basic info, get extended text details    for d in devices.keys():        # get additional info and add it to existing data        devices[d] = devices[d].copy()        devices[d].update(get_pci_device_details(d).items())        for _if in ssh_if:            if _if in devices[d]["Interface"].split(","):                devices[d]["Ssh_if"] = True                devices[d]["Active"] = "*Active*"                break        # add igb_uio to list of supporting modules if needed        if "Module_str" in devices[d]:            for driver in dpdk_drivers:                if driver not in devices[d]["Module_str"]:                    devices[d]["Module_str"] = \                        devices[d]["Module_str"] + ",%s" % driver        else:            devices[d]["Module_str"] = ",".join(dpdk_drivers)        # make sure the driver and module strings do not have any duplicates        if has_driver(d):            modules = devices[d]["Module_str"].split(",")            if devices[d]["Driver_str"] in modules:                modules.remove(devices[d]["Driver_str"])                devices[d]["Module_str"] = ",".join(modules)#从名字获取iddef dev_id_from_dev_name(dev_name):    '''Take a device "name" - a string passed in by user to identify a NIC    device, and determine the device id - i.e. the domain:bus:slot.func - for    it, which can then be used to index into the devices array'''    # check if it's already a suitable index    if dev_name in devices:        return dev_name    # check if it's an index just missing the domain part    elif "0000:" + dev_name in devices:        return "0000:" + dev_name    else:        # check if it's an interface name, e.g. eth1        for d in devices.keys():            if dev_name in devices[d]["Interface"].split(","):                return devices[d]["Slot"]    # if nothing else matches - error    print("Unknown device: %s. "          "Please specify device in \"bus:slot.func\" format" % dev_name)    sys.exit(1)#将驱动和网卡关系解绑def unbind_one(dev_id, force):    '''Unbind the device identified by "dev_id" from its current driver'''    dev = devices[dev_id]    if not has_driver(dev_id):        print("%s %s %s is not currently managed by any driver\n" %              (dev["Slot"], dev["Device_str"], dev["Interface"]))        return    # prevent us disconnecting ourselves    if dev["Ssh_if"] and not force:        print("Routing table indicates that interface %s is active. "              "Skipping unbind" % (dev_id))        return    # write to /sys to unbind    filename = "/sys/bus/pci/drivers/%s/unbind" % dev["Driver_str"]    #如：/sys/bus/pci/drivers/igb_uio/unbind    try:        f = open(filename, "a")     except:        print("Error: unbind failed for %s - Cannot open %s"              % (dev_id, filename))        sys.exit(1)    f.write(dev_id) #将设备id写入    f.close()#绑定设备，如果设备已经绑定到其他驱动，则首先进行解绑。def bind_one(dev_id, driver, force):    '''Bind the device given by "dev_id" to the driver "driver". If the device    is already bound to a different driver, it will be unbound first'''    dev = devices[dev_id]    saved_driver = None  # used to rollback any unbind in case of failure    # prevent disconnection of our ssh session 防止将ssh连接的网卡重新绑定，导致ssh连接断开    if dev["Ssh_if"] and not force:        print("Routing table indicates that interface %s is active. "              "Not modifying" % (dev_id))        return    # unbind any existing drivers we don't want    if has_driver(dev_id):        if dev["Driver_str"] == driver:            print("%s already bound to driver %s, skipping\n"                  % (dev_id, driver))            return        else:            saved_driver = dev["Driver_str"]            unbind_one(dev_id, force)            dev["Driver_str"] = ""  # clear driver string    # if we are binding to one of DPDK drivers, add PCI id's to that driver    if driver in dpdk_drivers:        filename = "/sys/bus/pci/drivers/%s/new_id" % driver        try:            f = open(filename, "w")        except:            print("Error: bind failed for %s - Cannot open %s"                  % (dev_id, filename))            return        try:            f.write("%04x %04x" % (dev["Vendor"], dev["Device"]))            f.close()        except:            print("Error: bind failed for %s - Cannot write new PCI ID to "                  "driver %s" % (dev_id, driver))            return    # do the bind by writing to /sys    filename = "/sys/bus/pci/drivers/%s/bind" % driver    try:        f = open(filename, "a")    except:        print("Error: bind failed for %s - Cannot open %s"              % (dev_id, filename))        if saved_driver is not None:  # restore any previous driver            bind_one(dev_id, saved_driver, force)        return    try:        f.write(dev_id)        f.close()    except:        # for some reason, closing dev_id after adding a new PCI ID to new_id        # results in IOError. however, if the device was successfully bound,        # we don't care for any errors and can safely ignore IOError        tmp = get_pci_device_details(dev_id)        if "Driver_str" in tmp and tmp["Driver_str"] == driver:            return        print("Error: bind failed for %s - Cannot bind to driver %s"              % (dev_id, driver))        if saved_driver is not None:  # restore any previous driver            bind_one(dev_id, saved_driver, force)        returndef unbind_all(dev_list, force=False):    """Unbind method, takes a list of device locations"""    dev_list = map(dev_id_from_dev_name, dev_list)    for d in dev_list:        unbind_one(d, force)#绑定一个网卡def bind_all(dev_list, driver, force=False):    """Bind method, takes a list of device locations"""    global devices    dev_list = map(dev_id_from_dev_name, dev_list)    for d in dev_list:        bind_one(d, driver, force)    # when binding devices to a generic driver (i.e. one that doesn't have a    # PCI ID table), some devices that are not bound to any other driver could    # be bound even if no one has asked them to. hence, we check the list of    # drivers again, and see if some of the previously-unbound devices were    # erroneously bound.    for d in devices.keys():        # skip devices that were already bound or that we know should be bound        if "Driver_str" in devices[d] or d in dev_list:            continue        # update information about this device        devices[d] = dict(devices[d].items() +                          get_pci_device_details(d).items())        # check if updated information indicates that the device was bound        if "Driver_str" in devices[d]:            unbind_one(d, force)def display_devices(title, dev_list, extra_params=None):    '''Displays to the user the details of a list of devices given in    "dev_list". The "extra_params" parameter, if given, should contain a string     with %()s fields in it for replacement by the named fields in each     device's dictionary.'''    strings = []  # this holds the strings to print. We sort before printing    print("\n%s" % title)    print("="*len(title))    if len(dev_list) == 0:        strings.append("<none>")    else:        for dev in dev_list:            if extra_params is not None:                strings.append("%s '%s' %s" % (dev["Slot"],                               dev["Device_str"], extra_params % dev))            else:                strings.append("%s '%s'" % (dev["Slot"], dev["Device_str"]))    # sort before printing, so that the entries appear in PCI order    strings.sort()    print("\n".join(strings))  # print one per linedef show_status():    '''Function called when the script is passed the "--status" option.    Displays to the user what devices are bound to the igb_uio driver, the    kernel driver or to no driver'''    global dpdk_drivers    kernel_drv = []    dpdk_drv = []    no_drv = []    # split our list of devices into the three categories above    for d in devices.keys():        if not has_driver(d):            no_drv.append(devices[d])            continue        if devices[d]["Driver_str"] in dpdk_drivers:            dpdk_drv.append(devices[d])        else:            kernel_drv.append(devices[d])    # print each category separately, so we can clearly see what's used by DPDK    display_devices("Network devices using DPDK-compatible driver", dpdk_drv,                    "drv=%(Driver_str)s unused=%(Module_str)s")    display_devices("Network devices using kernel driver", kernel_drv,                    "if=%(Interface)s drv=%(Driver_str)s "                    "unused=%(Module_str)s %(Active)s")    display_devices("Other network devices", no_drv, "unused=%(Module_str)s")#处理参数def parse_args():    '''Parses the command-line arguments given by the user and takes the    appropriate action for each'''    global b_flag  #表示使用全局的变量    global status_flag    global force_flag    global args    if len(sys.argv) <= 1:        usage()        sys.exit(0)    try:        opts, args = getopt.getopt(sys.argv[1:], "b:us",                                   ["help", "usage", "status", "force",                                    "bind=", "unbind"])    except getopt.GetoptError as error:        print(str(error))        print("Run '%s --usage' for further information" % sys.argv[0])        sys.exit(1)    for opt, arg in opts:        if opt == "--help" or opt == "--usage":            usage()            sys.exit(0)        if opt == "--status" or opt == "-s":            status_flag = True        if opt == "--force":            force_flag = True        if opt == "-b" or opt == "-u" or opt == "--bind" or opt == "--unbind":            if b_flag is not None:                print("Error - Only one bind or unbind may be specified\n")                sys.exit(1)            if opt == "-u" or opt == "--unbind":                b_flag = "none"            else:                b_flag = arg#相应客户真正需求def do_arg_actions():    '''do the actual action requested by the user'''    global b_flag    global status_flag    global force_flag    global args    if b_flag is None and not status_flag:        print("Error: No action specified for devices."              "Please give a -b or -u option")        print("Run '%s --usage' for further information" % sys.argv[0])        sys.exit(1)    if b_flag is not None and len(args) == 0:        print("Error: No devices specified.")        print("Run '%s --usage' for further information" % sys.argv[0])        sys.exit(1)    if b_flag == "none" or b_flag == "None":        unbind_all(args, force_flag) #解绑所有网卡绑定    elif b_flag is not None:        bind_all(args, b_flag, force_flag)    if status_flag:        if b_flag is not None:            get_nic_details()  # refresh if we have changed anything        show_status()def main():    '''program main function'''    parse_args()    check_modules()    get_nic_details()    do_arg_actions()if __name__ == "__main__":    main()

0x03 总结

    python脚本有sys/os/getopt/subprocess/等模块，使用了一些特殊表达式。