.IP \fBtun_id=\fItunnel-id\fR[\fB/\fImask\fR]
Matches tunnel identifier \fItunnel-id\fR. Only packets that arrive
over a tunnel that carries a key (e.g. GRE with the RFC 2890 key
-extension) will have a nonzero tunnel ID. If \fImask\fR is omitted,
-\fItunnel-id\fR is the exact tunnel ID to match; if \fImask\fR is
-specified, then a 1-bit in \fImask\fR indicates that the corresponding
-bit in \fItunnel-id\fR must match exactly, and a 0-bit wildcards that
-bit.
+extension and a nonzero key value) will have a nonzero tunnel ID.
+If \fImask\fR is omitted, \fItunnel-id\fR is the exact tunnel ID to match;
+if \fImask\fR is specified, then a 1-bit in \fImask\fR indicates that the
+corresponding bit in \fItunnel-id\fR must match exactly, and a 0-bit
+wildcards that bit.
.
.IP "\fBreg\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in