packet.7: Rework description of fanout algorithms as list

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/packet.7

@@ -287,7 +287,10 @@ flags (see below).
 Packet sockets can leave a fanout group only by closing the socket.
 The group is deleted when the last socket is closed.
 
-Fanout supports multiple algorithms to spread traffic between sockets.
+Fanout supports multiple algorithms to spread traffic between sockets,
+as follows:
+.RS
+.IP * 3
 The default mode,
 .BR PACKET_FANOUT_HASH ,
 sends packets from the same flow to the same socket to maintain
@@ -295,21 +298,27 @@ per-flow ordering.
 For each packet, it chooses a socket by taking the packet flow hash
 modulo the number of sockets in the group, where a flow hash is a hash
 over network-layer address and optional transport-layer port fields.
+.IP *
 The load-balance mode
 .BR PACKET_FANOUT_LB
 implements a round-robin algorithm.
+.IP *
 .BR PACKET_FANOUT_CPU
 selects the socket based on the CPU that the packet arrived on.
+.IP *
 .BR PACKET_FANOUT_ROLLOVER
 processes all data on a single socket, moving to the next when one
 becomes backlogged.
+.IP *
 .BR PACKET_FANOUT_RND
 selects the socket using a pseudo-random number generator.
+.IP *
 .BR PACKET_FANOUT_QM
 .\" commit 2d36097d26b5991d71a2cf4a20c1a158f0f1bfcd
 (available since Linux 3.14)
 selects the socket using the recorded queue_mapping of the received skb.
-
+.RE
+.IP
 Fanout modes can take additional options.
 IP fragmentation causes packets from the same flow to have different
 flow hashes.