+
+.IP \fBmod_nw_src\fB:\fIip\fR
+Sets the IPv4 source address to \fIip\fR.
+
+.IP \fBmod_nw_dst\fB:\fIip\fR
+Sets the IPv4 destination address to \fIip\fR.
+
+.IP \fBmod_tp_src\fB:\fIport\fR
+Sets the TCP or UDP source port to \fIport\fR.
+
+.IP \fBmod_tp_dst\fB:\fIport\fR
+Sets the TCP or UDP destination port to \fIport\fR.
+
+.IP \fBmod_nw_tos\fB:\fItos\fR
+Sets the IP ToS/DSCP field to \fItos\fR. Valid values are between 0 and
+255, inclusive. Note that the two lower reserved bits are never
+modified.
+