From 9d9b724cab2276a1ffa43e8376f2ed10282d07da Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Sat, 7 Apr 2018 00:44:49 +0200
Subject: xtables-compat: skip unsupported tables

Instead of not listing anything at all if an unknown table name
exists, just skip them.  Output a small comment that the listing
doesn't include the (unrecognized, nft-created) tables.

Next patch will restrict 'is this table printable in
xtables syntax' check to the "builtin" tables.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 iptables/nft.c          | 45 ++++-----------------------------------------
 iptables/nft.h          |  1 +
 iptables/xtables-save.c |  8 +++++++-
 iptables/xtables.c      |  3 ++-
 4 files changed, 14 insertions(+), 43 deletions(-)

diff --git a/iptables/nft.c b/iptables/nft.c
index a73c72bd..7c1e19d6 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -2842,49 +2842,16 @@ next:
 	return ret;
 }
 
-static int nft_is_table_compatible(const char *name)
+bool nft_is_table_compatible(struct nft_handle *h, const char *name)
 {
 	int i;
 
 	for (i = 0; i < TABLES_MAX; i++) {
-		if (strcmp(xtables_ipv4[i].name, name) == 0)
-			return 0;
-	}
-
-	return 1;
-}
-
-static int nft_are_tables_compatible(struct nft_handle *h)
-{
-	struct nftnl_table_list *list;
-	struct nftnl_table_list_iter *iter;
-	struct nftnl_table *table;
-	int ret = 0;
-
-	list = nftnl_table_list_get(h);
-	if (list == NULL)
-		return -1;
-
-	iter = nftnl_table_list_iter_create(list);
-	if (iter == NULL)
-		return -1;
-
-	table = nftnl_table_list_iter_next(iter);
-	while (table != NULL) {
-		const char *name = nftnl_table_get(table, NFTNL_TABLE_NAME);
-
-		if (nft_is_table_compatible(name) == 0) {
-			table = nftnl_table_list_iter_next(iter);
-			continue;
-		}
-
-		ret = 1;
-		break;
+		if (strcmp(h->tables[i].name, name) == 0)
+			return true;
 	}
 
-	nftnl_table_list_iter_destroy(iter);
-	nftnl_table_list_free(list);
-	return ret;
+	return false;
 }
 
 int nft_is_ruleset_compatible(struct nft_handle *h)
@@ -2895,10 +2862,6 @@ int nft_is_ruleset_compatible(struct nft_handle *h)
 	struct nftnl_rule *rule;
 	int ret = 0;
 
-	ret = nft_are_tables_compatible(h);
-	if (ret != 0)
-		return ret;
-
 	ret = nft_are_chains_compatible(h);
 	if (ret != 0)
 		return ret;
diff --git a/iptables/nft.h b/iptables/nft.h
index 41265930..310cedec 100644
--- a/iptables/nft.h
+++ b/iptables/nft.h
@@ -183,5 +183,6 @@ int nft_arp_rule_insert(struct nft_handle *h, const char *chain,
 void nft_rule_to_arpt_entry(struct nftnl_rule *r, struct arpt_entry *fw);
 
 int nft_is_ruleset_compatible(struct nft_handle *h);
+bool nft_is_table_compatible(struct nft_handle *h, const char *name);
 
 #endif
diff --git a/iptables/xtables-save.c b/iptables/xtables-save.c
index 5b498b04..893b2b93 100644
--- a/iptables/xtables-save.c
+++ b/iptables/xtables-save.c
@@ -52,6 +52,11 @@ do_output(struct nft_handle *h, const char *tablename, bool counters)
 		return 0;
 	}
 
+	if (!nft_is_table_compatible(h, tablename)) {
+		printf("# Table `%s' is incompatible, use 'nft' tool.\n", tablename);
+		return 1;
+	}
+
 	chain_list = nft_chain_dump(h);
 
 	time_t now = time(NULL);
@@ -160,7 +165,8 @@ xtables_save_main(int family, const char *progname, int argc, char *argv[])
 		exit(1);
 	}
 
-	if (nft_is_ruleset_compatible(&h) == 1) {
+	ret = nft_is_ruleset_compatible(&h);
+	if (ret) {
 		printf("ERROR: You're using nft features that cannot be mapped to iptables, please keep using nft.\n");
 		exit(EXIT_FAILURE);
 	}
diff --git a/iptables/xtables.c b/iptables/xtables.c
index ac113254..5410952a 100644
--- a/iptables/xtables.c
+++ b/iptables/xtables.c
@@ -1225,7 +1225,8 @@ int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table,
 	case CMD_LIST:
 	case CMD_LIST|CMD_ZERO:
 	case CMD_LIST|CMD_ZERO_NUM:
-		if (nft_is_ruleset_compatible(h) == 1) {
+		ret = nft_is_ruleset_compatible(h);
+		if (ret) {
 			printf("ERROR: You're using nft features that cannot be mapped to iptables, please keep using nft.\n");
 			exit(EXIT_FAILURE);
 		}
-- 
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