extensions: support for per-extension instance "global" variable space

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

2 files changed, 22 insertions, 0 deletions

diff --git a/iptables/xshared.c b/iptables/xshared.c
index 55ce5504..79da507d 100644
--- a/iptables/xshared.c
+++ b/iptables/xshared.c
@@ -209,12 +209,30 @@ int subcmd_main(int argc, char **argv, const struct subcommand *cb)
 
 void xs_init_target(struct xtables_target *target)
 {
+	if (target->udata_size != 0) {
+		free(target->udata);
+		target->udata = calloc(1, target->udata_size);
+		if (target->udata == NULL)
+			xtables_error(RESOURCE_PROBLEM, "malloc");
+	}
 	if (target->init != NULL)
 		target->init(target->t);
 }
 
 void xs_init_match(struct xtables_match *match)
 {
+	if (match->udata_size != 0) {
+		/*
+		 * As soon as a subsequent instance of the same match
+		 * is used, e.g. "-m time -m time", the first instance
+		 * is no longer reachable anyway, so we can free udata.
+		 * Same goes for target.
+		 */
+		free(match->udata);
+		match->udata = calloc(1, match->udata_size);
+		if (match->udata == NULL)
+			xtables_error(RESOURCE_PROBLEM, "malloc");
+	}
 	if (match->init != NULL)
 		match->init(match->m);
 }
diff --git a/iptables/xtoptions.c b/iptables/xtoptions.c
index ac0601f2..1423724b 100644
--- a/iptables/xtoptions.c
+++ b/iptables/xtoptions.c
@@ -908,6 +908,7 @@ void xtables_option_tpcall(unsigned int c, char **argv, bool invert,
 	cb.xflags   = t->tflags;
 	cb.target   = &t->t;
 	cb.xt_entry = fw;
+	cb.udata    = t->udata;
 	t->x6_parse(&cb);
 	t->tflags = cb.xflags;
 }
@@ -943,6 +944,7 @@ void xtables_option_mpcall(unsigned int c, char **argv, bool invert,
 	cb.xflags   = m->mflags;
 	cb.match    = &m->m;
 	cb.xt_entry = fw;
+	cb.udata    = m->udata;
 	m->x6_parse(&cb);
 	m->mflags = cb.xflags;
 }
@@ -1028,6 +1030,7 @@ void xtables_option_tfcall(struct xtables_target *t)
 		cb.ext_name = t->name;
 		cb.data     = t->t->data;
 		cb.xflags   = t->tflags;
+		cb.udata    = t->udata;
 		t->x6_fcheck(&cb);
 	} else if (t->final_check != NULL) {
 		t->final_check(t->tflags);
@@ -1048,6 +1051,7 @@ void xtables_option_mfcall(struct xtables_match *m)
 		cb.ext_name = m->name;
 		cb.data     = m->m->data;
 		cb.xflags   = m->mflags;
+		cb.udata    = m->udata;
 		m->x6_fcheck(&cb);
 	} else if (m->final_check != NULL) {
 		m->final_check(m->mflags);