netfilter: add xt_hmark target for hash-based skb marking

The target allows you to create rules in the "raw" and "mangle" tables
which set the skbuff mark by means of hash calculation within a given
range. The nfmark can influence the routing method (see "Use netfilter
MARK value as routing key") and can also be used by other subsystems to
change their behaviour.

[ Part of this patch has been refactorized and modified by Pablo Neira Ayuso ]

Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index ca36765..4e7960c 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -59,6 +59,7 @@
 obj-$(CONFIG_NETFILTER_XT_TARGET_CT) += xt_CT.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_DSCP) += xt_DSCP.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_HL) += xt_HL.o
+obj-$(CONFIG_NETFILTER_XT_TARGET_HMARK) += xt_HMARK.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_LED) += xt_LED.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_LOG) += xt_LOG.o
 obj-$(CONFIG_NETFILTER_XT_TARGET_NFLOG) += xt_NFLOG.o