[iptables PATCH 09/18] nft: Use nftnl_chain_list_foreach in nft_rule_list{,_save}

[Phil Sutter <phil@xxxxxx>]

Introduce a common callback function and data structure to pass via
opaque pointer since chain printing in both functions is pretty similar.

Signed-off-by: Phil Sutter <phil@xxxxxx>
---
 iptables/nft.c | 89 +++++++++++++++++++++++++++-----------------------
 1 file changed, 49 insertions(+), 40 deletions(-)

diff --git a/iptables/nft.c b/iptables/nft.c
index cc1260dc627d0..66746818f5e0c 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -2424,14 +2424,43 @@ static void __nft_print_header(struct nft_handle *h,
 			&ctrs, basechain, refs - entries, entries);
 }
 
+struct nft_rule_list_cb_data {
+	struct nft_handle *h;
+	unsigned int format;
+	int rulenum;
+	bool found;
+	bool save_fmt;
+	void (*cb)(struct nft_handle *h, struct nftnl_rule *r,
+		   unsigned int num, unsigned int format);
+};
+
+static int nft_rule_list_cb(struct nftnl_chain *c, void *data)
+{
+	struct nft_rule_list_cb_data *d = data;
+
+	if (!d->save_fmt) {
+		if (d->found)
+			printf("\n");
+		d->found = true;
+
+		__nft_print_header(d->h, c, d->format);
+	}
+
+	return __nft_rule_list(d->h, c, d->rulenum, d->format, d->cb);
+}
+
 int nft_rule_list(struct nft_handle *h, const char *chain, const char *table,
 		  int rulenum, unsigned int format)
 {
 	const struct nft_family_ops *ops = h->ops;
+	struct nft_rule_list_cb_data d = {
+		.h = h,
+		.format = format,
+		.rulenum = rulenum,
+		.cb = ops->print_rule,
+	};
 	struct nftnl_chain_list *list;
-	struct nftnl_chain_list_iter *iter;
 	struct nftnl_chain *c;
-	bool found = false;
 
 	nft_xt_builtin_init(h, table);
 	nft_assert_table_compatible(h, table, chain);
@@ -2441,12 +2470,12 @@ int nft_rule_list(struct nft_handle *h, const char *chain, const char *table,
 		if (!c)
 			return 0;
 
-		if (!rulenum) {
-			if (ops->print_table_header)
-				ops->print_table_header(table);
-			__nft_print_header(h, c, format);
-		}
-		__nft_rule_list(h, c, rulenum, format, ops->print_rule);
+		if (rulenum)
+			d.save_fmt = true;	/* skip header printing */
+		else if (ops->print_table_header)
+			ops->print_table_header(table);
+
+		nft_rule_list_cb(c, &d);
 		return 1;
 	}
 
@@ -2454,25 +2483,10 @@ int nft_rule_list(struct nft_handle *h, const char *chain, const char *table,
 	if (!list)
 		return 0;
 
-	iter = nftnl_chain_list_iter_create(list);
-	if (iter == NULL)
-		return 0;
-
 	if (ops->print_table_header)
 		ops->print_table_header(table);
 
-	c = nftnl_chain_list_iter_next(iter);
-	while (c != NULL) {
-		if (found)
-			printf("\n");
-
-		__nft_print_header(h, c, format);
-		__nft_rule_list(h, c, rulenum, format, ops->print_rule);
-
-		found = true;
-		c = nftnl_chain_list_iter_next(iter);
-	}
-	nftnl_chain_list_iter_destroy(iter);
+	nftnl_chain_list_foreach(list, nft_rule_list_cb, &d);
 	return 1;
 }
 
@@ -2527,9 +2541,13 @@ nftnl_rule_list_chain_save(struct nft_handle *h, const char *chain,
 int nft_rule_list_save(struct nft_handle *h, const char *chain,
 		       const char *table, int rulenum, int counters)
 {
+	struct nft_rule_list_cb_data d = {
+		.h = h,
+		.rulenum = rulenum,
+		.save_fmt = true,
+		.cb = list_save,
+	};
 	struct nftnl_chain_list *list;
-	struct nftnl_chain_list_iter *iter;
-	unsigned int format = 0;
 	struct nftnl_chain *c;
 	int ret = 0;
 
@@ -2545,30 +2563,21 @@ int nft_rule_list_save(struct nft_handle *h, const char *chain,
 		nftnl_rule_list_chain_save(h, chain, list, counters);
 
 	if (counters < 0)
-		format = FMT_C_COUNTS;
+		d.format = FMT_C_COUNTS;
 	else if (counters == 0)
-		format = FMT_NOCOUNTS;
+		d.format = FMT_NOCOUNTS;
 
 	if (chain) {
 		c = nftnl_chain_list_lookup_byname(list, chain);
 		if (!c)
 			return 0;
 
-		return __nft_rule_list(h, c, rulenum, format, list_save);
+		return nft_rule_list_cb(c, &d);
 	}
 
 	/* Now dump out rules in this table */
-	iter = nftnl_chain_list_iter_create(list);
-	if (iter == NULL)
-		return 0;
-
-	c = nftnl_chain_list_iter_next(iter);
-	while (c != NULL) {
-		ret = __nft_rule_list(h, c, rulenum, format, list_save);
-		c = nftnl_chain_list_iter_next(iter);
-	}
-	nftnl_chain_list_iter_destroy(iter);
-	return ret;
+	ret = nftnl_chain_list_foreach(list, nft_rule_list_cb, &d);
+	return ret == 0 ? 1 : 0;
 }
 
 int nft_rule_zero_counters(struct nft_handle *h, const char *chain,
-- 
2.27.0