iptables-compat fixes

Here are the first patches from my tests with iptables-compat and firewalld:

The first patch is enabling to insert a rule into rule_count+1 position.

# iptables-compat -t filter -S INPUT
-P INPUT ACCEPT
[0:0] -A INPUT -s 1.2.3.4/32 -j DROP
# iptables-compat -t filter -I INPUT 2 -s 1.2.3.5 -j DROP 
# iptables-compat -t filter -S INPUT
-P INPUT ACCEPT
[0:0] -A INPUT -s 1.2.3.4/32 -j DROP
[0:0] -A INPUT -s 1.2.3.5/32 -j DROP
This is possible with iptables, but not possible with iptables-compat.
Maybe it would be good to add nft_rule_list_count or similar and use it here.

The second patch fixes the rule number handling in nft_rule_find and __nft_rule_list. The rule number is only valid in the selected table and chain and therefore may not be increased for other tables or chains. With this patch the correct rule will be removed with -D <name> i and listed with -S <name> i.

Thomas Woerner (2):
iptables-compat: Allow to insert into rule_count+1 position
iptables-compat: Increase rule number only for the selected table and
chain

 iptables/nft.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

2.4.3

iptables allows to insert a rule into the next non existing rule number but iptables-compat does not allow to do this

---
:100644 100644 7cd56ef... 323f124... M iptables/nft.c

 iptables/nft.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

index 7cd56ef..323f124 100644
@@ -1854,6 +1854,16 @@ int nft_rule_insert(struct nft_handle *h, const char *chain,
 
 		r = nft_rule_find(h, list, chain, table, data, rulenum);
 		if (r == NULL) {
+			/* special case: iptables allows to insert into
+			   rule_count+1 position */
+			r = nft_rule_find(h, list, chain, table, data,
+					  rulenum-1);
+			if (r != NULL) {
+				nft_rule_list_destroy(list);
+				return nft_rule_append(h, chain, table, data,
+						       0, verbose);
+			}
+
 			errno = ENOENT;
 			goto err;
 		}

2.4.3

This patch fixes the rule number handling in nft_rule_find and __nft_rule_list. The rule number is only valid in the selected table and chain and therefore may not be increased for other tables or chains.

---
:100644 100644 323f124... 139cf5a... M iptables/nft.c

 iptables/nft.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

index 323f124..139cf5a 100644
@@ -1746,17 +1746,17 @@ nft_rule_find(struct nft_handle *h, struct nft_rule_list *list,
 
 		if (rulenum >= 0) {
 			/* Delete by rule number case */
-			if (rule_ctr != rulenum)
-				goto next;
-			found = true;
-			break;
+			if (rule_ctr == rulenum) {
+			    found = true;
+			    break;
+			}
 		} else {
 			found = h->ops->rule_find(h->ops, r, data);
 			if (found)
 				break;
 		}
-next:
 		rule_ctr++;
+next:
 		r = nft_rule_list_iter_next(iter);
 	}
 

@@ -1965,12 +1965,12 @@ __nft_rule_list(struct nft_handle *h, const char *chain, const char *table,
 		const char *rule_chain =
 			nft_rule_attr_get_str(r, NFT_RULE_ATTR_CHAIN);
 
-		rule_ctr++;
-
 		if (strcmp(table, rule_table) != 0 ||
 		    strcmp(chain, rule_chain) != 0)
 			goto next;
 
+		rule_ctr++;
+
 		if (rulenum > 0 && rule_ctr != rulenum) {
 			/* List by rule number case */
 			goto next;

2.4.3

Series applied, thanks Thomas!