From: Ted Lemon <source@isc.org>
Date: Tue, 6 Jul 1999 20:19:40 +0000 (+0000)
Subject: Document binary-to-ascii, leased-address and reverse.
X-Git-Tag: V3-BETA-1-PATCH-0~12
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8ca01a7ef1b310067871c36387481b7f78982747;p=thirdparty%2Fdhcp.git

Document binary-to-ascii, leased-address and reverse.
---

diff --git a/common/dhcp-eval.5 b/common/dhcp-eval.5
index 2f988d4bb..042da4a6b 100644
--- a/common/dhcp-eval.5
+++ b/common/dhcp-eval.5
@@ -246,6 +246,49 @@ expression.   If both expressions evaluate to null, then the result is
 null.
 .RE
 .PP
+.PP
+.B reverse (\fInumeric-expr1\fB, \fIdata-expr2\fB)\fR
+.RS 0.25i
+The two expressions are evaluated, and then the result of evaluating
+the data expression is reversed in place, using hunks of the size
+specified in the numeric expression.   For example, if the numeric
+expression evaluates to four, and the data expression evaluates to 
+twelve bytes of data, then the reverse expression will evaluate to
+twelve bytes of data, consisting of the last four bytes of the the
+input data, followed by the middle four bytes, followed by the first
+four bytes.
+.RE
+.PP
+.B leased-address
+.RS 0.25i
+In any context where the client whose request is being processed has
+been assigned an IP address, this data expression returns that IP
+address.
+.RE
+.PP
+.B binary-to-ascii (\fInumeric-expr1\fB, \fInumeric-expr2\fB,
+.B \fIdata-expr1\fB,\fR \fIdata-expr2\fB)\fR
+.RS 0.25i
+Converts the result of evaluating data-expr2 into a text string
+containing one number for each element of the result of evaluating
+data-expr2.   Each number is seperated from the other by the result of
+evaluating data-expr1.   The result of evaluating numeric-expr1
+specifies the base (2 through 16) into which the numbers should be
+converted.   The result of evaluating numeric-expr2 specifies the
+width in bits of each number, which may be either 8, 16 or 32.
+.PP
+As an example of the preceding three types of expressions, to produce
+the name of a PTR record for the IP address being assigned to a
+client, one could write the following expression:
+.RE
+.PP
+.nf
+        concat (binary-to-ascii (10, 8, ".",
+                                 reverse (1, leased-address)),
+                ".in-addr.arpa.");
+
+.fi
+.PP
 .B encode-int (\fInumeric-expr\fB, \fIwidth\fB)\fR
 .RS 0.25i
 Numeric-expr is evaluated and encoded as a data string of the