+\fIfields\fR must be one of the following:
+.RS
+.IP \fBeth_src\fR
+Hashes Ethernet source address only.
+.IP \fBsymmetric_l4\fR
+Hashes Ethernet source, destination, and type, VLAN ID, IPv4/IPv6
+source, destination, and protocol, and TCP or SCTP (but not UDP)
+ports. The hash is computed so that pairs of corresponding flows in
+each direction hash to the same value, in environments where L2 paths
+are the same in each direction. UDP ports are not included in the
+hash to support protocols such as VXLAN that use asymmetric ports in
+each direction.
+.IP \fBsymmetric_l3l4\fR
+Hashes IPv4/IPv6 source, destination, and protocol, and TCP or SCTP
+(but not UDP) ports. Like \fBsymmetric_l4\fR, this is a symmetric
+hash, but by excluding L2 headers it is more effective in environments
+with asymmetric L2 paths (e.g. paths involving VRRP IP addresses on a
+router). Not an effective hash function for protocols other than IPv4
+and IPv6, which hash to a constant zero.
+.IP \fBsymmetric_l3l4+udp\fR
+Like \fBsymmetric_l3l4+udp\fR, but UDP ports are included in the hash.
+This is a more effective hash when asymmetric UDP protocols such as
+VXLAN are not a consideration.
+.RE
+.IP
+\fIalgorithm\fR must be one of \fBmodulo_n\fR,