iptables/0036-extensions-libxt_conntrack-use-bitops-for-state-nega.patch

From db7d25c14b8db7f7ea514e1f81acb82fafb3c9d7 Mon Sep 17 00:00:00 2001
From: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Date: Thu, 1 Apr 2021 16:47:07 +0300
Subject: [PATCH] extensions: libxt_conntrack: use bitops for state negation

Currently, state_xlate_print function prints statemask as comma-separated sequence of enabled
statemask flags. But if we have inverted conntrack ctstate condition then we have to use more
complex expression because nft not supports syntax like "ct state != related,established".

Reproducer:
$ iptables -A INPUT -d 127.0.0.1/32 -p tcp -m conntrack ! --ctstate RELATED,ESTABLISHED -j DROP
$ nft list ruleset
...
meta l4proto tcp ip daddr 127.0.0.1 ct state != related,established counter packets 0 bytes 0 drop
...

it will fail if we try to load this rule:
$ nft -f nft_test
../nft_test:6:97-97: Error: syntax error, unexpected comma, expecting newline or semicolon

Cc: Florian Westphal <fw@strlen.de>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
(cherry picked from commit 18e334da7363ba186edb1700056e26ded27ca5ba)
---
 extensions/libxt_conntrack.c      | 38 ++++++++++++++++++++-----------
 extensions/libxt_conntrack.txlate |  5 +++-
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/extensions/libxt_conntrack.c b/extensions/libxt_conntrack.c
index 7734509c9af84..91f9e4aa994f8 100644
--- a/extensions/libxt_conntrack.c
+++ b/extensions/libxt_conntrack.c
@@ -1148,30 +1148,43 @@ static void state_save(const void *ip, const struct xt_entry_match *match)
 	state_print_state(sinfo->statemask);
 }
 
-static void state_xlate_print(struct xt_xlate *xl, unsigned int statemask)
+static void state_xlate_print(struct xt_xlate *xl, unsigned int statemask, int inverted)
 {
 	const char *sep = "";
+	int one_flag_set;
+
+	one_flag_set = !(statemask & (statemask - 1));
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, "& (");
+	else if (inverted)
+		xt_xlate_add(xl, "& ");
 
 	if (statemask & XT_CONNTRACK_STATE_INVALID) {
 		xt_xlate_add(xl, "%s%s", sep, "invalid");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_NEW)) {
 		xt_xlate_add(xl, "%s%s", sep, "new");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_RELATED)) {
 		xt_xlate_add(xl, "%s%s", sep, "related");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED)) {
 		xt_xlate_add(xl, "%s%s", sep, "established");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
 	if (statemask & XT_CONNTRACK_STATE_UNTRACKED) {
 		xt_xlate_add(xl, "%s%s", sep, "untracked");
-		sep = ",";
+		sep = inverted && !one_flag_set ? "|" : ",";
 	}
+
+	if (inverted && !one_flag_set)
+		xt_xlate_add(xl, ") == 0");
+	else if (inverted)
+		xt_xlate_add(xl, " == 0");
 }
 
 static int state_xlate(struct xt_xlate *xl,
@@ -1180,9 +1193,9 @@ static int state_xlate(struct xt_xlate *xl,
 	const struct xt_conntrack_mtinfo3 *sinfo =
 		(const void *)params->match->data;
 
-	xt_xlate_add(xl, "ct state %s", sinfo->invert_flags & XT_CONNTRACK_STATE ?
-					"!= " : "");
-	state_xlate_print(xl, sinfo->state_mask);
+	xt_xlate_add(xl, "ct state ");
+	state_xlate_print(xl, sinfo->state_mask,
+			  sinfo->invert_flags & XT_CONNTRACK_STATE);
 	xt_xlate_add(xl, " ");
 	return 1;
 }
@@ -1256,10 +1269,9 @@ static int _conntrack3_mt_xlate(struct xt_xlate *xl,
 				     sinfo->state_mask & XT_CONNTRACK_STATE_SNAT ? "snat" : "dnat");
 			space = " ";
 		} else {
-			xt_xlate_add(xl, "%sct state %s", space,
-				     sinfo->invert_flags & XT_CONNTRACK_STATE ?
-				     "!= " : "");
-			state_xlate_print(xl, sinfo->state_mask);
+			xt_xlate_add(xl, "%sct state ", space);
+			state_xlate_print(xl, sinfo->state_mask,
+					  sinfo->invert_flags & XT_CONNTRACK_STATE);
 			space = " ";
 		}
 	}
diff --git a/extensions/libxt_conntrack.txlate b/extensions/libxt_conntrack.txlate
index d374f8a035f00..5ab85b177c396 100644
--- a/extensions/libxt_conntrack.txlate
+++ b/extensions/libxt_conntrack.txlate
@@ -2,7 +2,10 @@ iptables-translate -t filter -A INPUT -m conntrack --ctstate NEW,RELATED -j ACCE
 nft add rule ip filter INPUT ct state new,related counter accept
 
 ip6tables-translate -t filter -A INPUT -m conntrack ! --ctstate NEW,RELATED -j ACCEPT
-nft add rule ip6 filter INPUT ct state != new,related counter accept
+nft add rule ip6 filter INPUT ct state & (new|related) == 0 counter accept
+
+ip6tables-translate -t filter -A INPUT -m conntrack ! --ctstate NEW -j ACCEPT
+nft add rule ip6 filter INPUT ct state & new == 0 counter accept
 
 iptables-translate -t filter -A INPUT -m conntrack --ctproto UDP -j ACCEPT
 nft add rule ip filter INPUT ct original protocol 17 counter accept
-- 
2.40.0