libxtables: Introduce global params structuring

introduce a new struct,xtables_globals, so as to
localize the globals used and help in symbol renames.
The applications must invoke xtables_set_params() before starting
to use any iptables APIs.
xtables_set_params() is intended to free xtables from depending
(as it does right now) on existence of such externally definitions
(from iptables/iptables6 etc). At the moment, xtables wont even
compile without presence of at least one of {iptables/iptables6 etc}

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/include/xtables.h.in b/include/xtables.h.in
index 02750fb..61dbc76 100644
--- a/include/xtables.h.in
+++ b/include/xtables.h.in
@@ -33,6 +33,14 @@
 
 struct in_addr;
 
+struct xtables_globals
+{
+	unsigned int option_offset;
+	char *program_version;
+	char *program_name;
+	struct option *opts;
+};
+
 /* Include file for additions: new matches and targets. */
 struct xtables_match
 {
@@ -195,6 +203,7 @@
 
 extern int xtables_insmod(const char *, const char *, bool);
 extern int xtables_load_ko(const char *, bool);
+int xtables_set_params(struct xtables_globals *xtp);
 
 extern struct xtables_match *xtables_find_match(const char *name,
 	enum xtables_tryload, struct xtables_rule_match **match);
diff --git a/xtables.c b/xtables.c
index 6c95475..aad5e53 100644
--- a/xtables.c
+++ b/xtables.c
@@ -46,6 +46,28 @@
 #define PROC_SYS_MODPROBE "/proc/sys/kernel/modprobe"
 #endif
 
+struct xtables_globals *xt_params;
+/**
+ * xtables_set_params - set the global parameters used by xtables
+ * @xtp:	input xtables_globals structure
+ *
+ * The app is expected to pass a valid xtables_globals data-filled
+ * with proper values
+ * @xtp cannot be NULL
+ *
+ * Returns -1 on failure to set and 0 on success
+ */
+int xtables_set_params(struct xtables_globals *xtp)
+{
+	if (!xtp) {
+		fprintf(stderr, "%s: Illegal global params\n",__func__);
+		return -1;
+	}
+
+	xt_params = xtp;
+	return 0;
+}
+
 /**
  * xtables_afinfo - protocol family dependent information
  * @kmod:		kernel module basename (e.g. "ip_tables")