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Diffstat (limited to '')
| -rw-r--r-- | raddb/mods-available/unpack | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/raddb/mods-available/unpack b/raddb/mods-available/unpack new file mode 100644 index 0000000..89ef169 --- /dev/null +++ b/raddb/mods-available/unpack @@ -0,0 +1,105 @@ +# -*- text -*- +# +# $Id$ + +# +# This module is useful only for 'xlat'. +# To use it, add it to the raddb/mods-enabled/ directory. +# +# Two xlat functions are provided by this module: +# - unpack +# - substring +# +# Both are for use on the right-hand side of a variable assignment. +# +# unpack +# ====== +# +# ... = "%{unpack:data 1 integer}" +# +# The arguments are three fields: +# +# data +# Either &Attribute-Name +# the name of the attribute to unpack. +# MUST be a "string" or "octets" type. +# +# or 0xabcdef +# e.g. hex data. +# +# 1 +# The offset into the string from which +# it starts unpacking. The offset starts +# at zero, for the first attribute. +# +# integer +# the data type to unpack at that offset. +# e.g. integer, ipaddr, byte, short, etc. +# +# e.g. if we have Class = 0x0000000102030405, then +# +# %{unpack:&Class 4 short} +# +# will unpack octets 4 and 5 as a "short", which has +# value 0x0304. +# +# This module is used when vendors put multiple fields +# into one attribute of type "octets". +# +# The module can also be used to unpack substrings, by specifing a +# data type of "string(len)" or "octets(len)". Where "len" is an +# actual number. For example: +# +# %{unpack:&User-Name 1 string(2)} +# +# When given a User-Name of "hello", it will start taking the +# substring at offset 1 (i.e. "e"), and it will take two characters +# from that offset, i.e. "el". +# +# As a special case, you can unpack an entire string by specifying +# the offset, and nothing for the length: +# +# %{unpack:&User-Name 1 string()} +# +# When "octets(len)" is used, the output is printed as hex. e.g. for +# the above example with Class: +# +# %{unpack:&Class 4 octets(4)} +# +# Will return the hex string "02030405" +# +# +# substring +# ========= +# +# substring will return a substring of a string or attribute using +# the syntax +# +# %{substring:data start len} +# +# data +# Either an attribute name or string data. String data +# can have leading or trailing spaces. Only a single +# space before "start" is taken as the separator. +# +# start +# the zero based offset for the start of the substring. +# A negative value will count in from the end of the +# string. +# +# len +# the number of characters to return. A Negative value +# will remove that number of characters from the end. +# If len is more than the available number of characters +# then only the available number will be returned. +# +# Examples: +# +# "%{substring:foobar 2 3}" == "oba" +# "%{substring:foobar -3 2}" == "ba" +# "%{substring:foobar 1 -1}" == "ooba" +# if User-Name is "foobar" "%{substring:&User-Name 1 -2}" == "oob" +# + +unpack { +} |