Add a sample script for making uefi netboot entries

This may be handy for manually configuring uefi network
boot entries locally

misc/makeuefinetbootentry.py

@@ -0,0 +1,82 @@
+import argparse
+import struct
+import os
+import sys
+
+# This script will create a PXE or HTTP boot entry specific for a linux nic using
+# convenience of the linux interface name. It can help produce precise network boot order
+# configuration more easily if that is useful
+
+# only tested with Lenovo system firmware on PCIe network adapters
+
+parser = argparse.ArgumentParser(description='Generate an efivars boot entry file')
+parser.add_argument('interface', help='Current linux interface name to boot from')
+parser.add_argument('outfile', help='The file to write, e.g. /sys/firmware/efi/efivars/Boot0007-8be4df61-93ca-11d2-aa0d-00e098032b8c')
+parser.add_argument('-u', help='The HTTP url to boot, "" for generic HTTP boot instead of PXE')
+args = parser.parse_args()
+with open('/sys/class/net/{0}/address'.format(sys.argv[1])) as macaddr:
+    macaddr = macaddr.read()
+    macaddr = macaddr.split(':')
+    macaddr = [ int(x, 16) for x in macaddr ]
+    macaddr = bytes(macaddr)
+
+olddir = os.getcwd()
+os.chdir('/sys/class/net/{0}'.format(sys.argv[1]))
+devdir = os.readlink('/sys/class/net/{0}/device'.format(sys.argv[1]))
+os.chdir(devdir)
+pcipath = os.getcwd()
+pcipath = pcipath.split('/')
+os.chdir('/'.join(pcipath[:4]))
+acpiid = os.readlink('firmware_node')
+os.chdir(acpiid)
+hid = '0A03' # do not adapt, always say pciroot, pcieroot doesn't work open('hid').read().replace('PNP', '')
+hid = int(hid, 16) << 16 | 0x41d0
+hid = struct.pack('<I', hid)
+uid = open('uid').read()
+uid = struct.pack('<I', int(uid, 16))
+pcipath = pcipath[4:]
+os.chdir(olddir)
+url = args.u
+if url is not None:
+    url = url.encode('utf8')
+
+with open(sys.argv[2], 'wb') as output:
+    output.write(struct.pack('<I', 7)) # write out attributes, for now always 7
+    output.write(struct.pack('<I', 1)) # write out attributes, for now always 1
+    # 0x50 is smallest, acpi, mac, and ip devpaths, each pci path hop adds 6 bytes
+    baselen = 0x50
+    if url is not None: #well, we need more length for http boot
+        baselen += len(url) + 4
+    output.write(struct.pack('<H', baselen + (len(pcipath) * 6)))
+    desc = sys.argv[1]
+    if url is None:
+        desc += '-pxe'
+    else:
+        desc += '-http'
+    output.write(desc.encode('utf16')[2:])
+    output.write(b'\x00\x00') # terminate the description
+    # first we need pciroot, which is an acpi path, table 52, HID is PNP0A03
+    output.write(b'\x02\x01\x0c\x00') # acpi devpath header
+    output.write(hid) # ACPI hid, either PciRoot or PcieRoot
+    output.write(uid) # ACPI uid of the pci root complex
+    for pcihop in pcipath:
+        pcihop = pcihop.rsplit(':', 1)[-1]
+        output.write(b'\x01\x01\x06\x00')
+        devnum, funnum = pcihop.split('.')
+        devnum = int(devnum, 16)
+        funnum = int(funnum, 16)
+        output.write(struct.pack('BB', funnum, devnum))
+    output.write(b'\x03\x0b\x25\x00')
+    output.write(macaddr)
+    output.write(b'\x00' * (32 - len(macaddr))) # pad out to the rest of the 32 bytes
+    output.write(b'\x01') # type is ethernet, 1, per rfc 3232
+    output.write(b'\x03\x0c\x1b\x00') # ipv4 header, table 71 from section 10.3.4.12
+    output.write(b'\x00' * 23) # all zero for the data
+    # if args.u, we need a Messaging device path, subtypee 24, uri, table 83
+    if url is not None:
+        output.write(b'\x03\x18')
+        output.write(struct.pack('<H', 4 + len(url)))
+        if url:
+            output.write(url)
+    output.write(b'\x7f\xff\x04\x00') # table 45, device path end structure
+