iprule: fix missing ip rules after a reload (FS#2296)

Since commit 5cf79759a24e9bb2a6a3aef7c83d73efb9bf2df3 (iprule: rework
interface based rules to handle dynamic interfaces) the rule
comparison is broken and doesn't correctly recognize matching rules.
This in turn break the reloading as adding the "new" rule fails
because it already exists and it then delete the "old" rule.

The comparison is broken because it now include fields that are not
defining the rule itself, as well as some pointer to malloced strings.
To fix this we move back the offending fields in the iprule struct
before the 'flags' field and match the malloced strings separately.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

2 files changed, 38 insertions, 11 deletions

diff --git a/iprule.c b/iprule.c
index 3e57888..c3a629f 100644
--- a/iprule.c
+++ b/iprule.c
@@ -290,7 +290,7 @@ iprule_add(struct blob_attr *attr, bool v6)
 		rule->flags |= IPRULE_GOTO;
 	}
 
-	vlist_add(&iprules, &rule->node, &rule->flags);
+	vlist_add(&iprules, &rule->node, rule);
 	return;
 
 error:
@@ -320,7 +320,32 @@ iprule_update_complete(void)
 static int
 rule_cmp(const void *k1, const void *k2, void *ptr)
 {
-	return memcmp(k1, k2, sizeof(struct iprule)-offsetof(struct iprule, flags));
+	const struct iprule *r1 = k1, *r2 = k2;
+	int ret;
+
+	/* First compare the interface names */
+	if (r1->flags & IPRULE_IN || r2->flags & IPRULE_IN) {
+		char *str1 = r1->flags & IPRULE_IN ? r1->in_iface : "";
+		char *str2 = r2->flags & IPRULE_IN ? r2->in_iface : "";
+
+		ret = strcmp(str1, str2);
+		if (ret)
+			return ret;
+	}
+
+	if (r1->flags & IPRULE_OUT || r2->flags & IPRULE_OUT) {
+		char *str1 = r1->flags & IPRULE_OUT ? r1->out_iface : "";
+		char *str2 = r2->flags & IPRULE_OUT ? r2->out_iface : "";
+
+		ret = strcmp(str1, str2);
+		if (ret)
+			return ret;
+	}
+
+	/* Next compare everything after the flags field */
+	return memcmp(k1 + offsetof(struct iprule, flags),
+		      k2 + offsetof(struct iprule, flags),
+		      sizeof(struct iprule) - offsetof(struct iprule, flags));
 }
 
 static void deregister_interfaces(struct iprule *rule)
diff --git a/iprule.h b/iprule.h
index f05c3c9..89b94b4 100644
--- a/iprule.h
+++ b/iprule.h
@@ -69,15 +69,6 @@ struct iprule {
 	struct vlist_node node;
 	unsigned int order;
 
-	/* everything below is used as avl tree key */
-	enum iprule_flags flags;
-
-	bool invert;
-
-	/* uci interface name */
-	char *in_iface;
-	char *out_iface;
-
 	/* to receive interface events */
 	struct interface_user in_iface_user;
 	struct interface_user out_iface_user;
@@ -86,6 +77,17 @@ struct iprule {
 	char in_dev[IFNAMSIZ + 1];
 	char out_dev[IFNAMSIZ + 1];
 
+	/* everything below is used as avl tree key */
+	/* don't change the order                   */
+
+	/* uci interface name */
+	char *in_iface;
+	char *out_iface;
+
+	enum iprule_flags flags;
+
+	bool invert;
+
 	unsigned int src_mask;
 	union if_addr src_addr;