[NET_SCHED]: Add mask support to fwmark classifier

Support masking the nfmark value before the search. The mask value is
global for all filters contained in one instance. It can only be set
when a new instance is created, all filters must specify the same mask.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/pkt_cls.h

@@ -305,6 +305,7 @@ enum
 	TCA_FW_POLICE,
 	TCA_FW_INDEV, /*  used by CONFIG_NET_CLS_IND */
 	TCA_FW_ACT, /* used by CONFIG_NET_CLS_ACT */
+	TCA_FW_MASK,
 	__TCA_FW_MAX
 };
 

net/sched/cls_fw.c

@@ -50,6 +50,7 @@
 struct fw_head
 {
 	struct fw_filter *ht[HTSIZE];
+	u32 mask;
 };
 
 struct fw_filter
@@ -101,7 +102,7 @@ static int fw_classify(struct sk_buff *skb, struct tcf_proto *tp,
 	struct fw_filter *f;
 	int r;
 #ifdef CONFIG_NETFILTER
-	u32 id = skb->nfmark;
+	u32 id = skb->nfmark & head->mask;
 #else
 	u32 id = 0;
 #endif
@@ -209,7 +210,9 @@ static int
 fw_change_attrs(struct tcf_proto *tp, struct fw_filter *f,
 	struct rtattr **tb, struct rtattr **tca, unsigned long base)
 {
+	struct fw_head *head = (struct fw_head *)tp->root;
 	struct tcf_exts e;
+	u32 mask;
 	int err;
 
 	err = tcf_exts_validate(tp, tb, tca[TCA_RATE-1], &e, &fw_ext_map);
@@ -232,6 +235,15 @@ fw_change_attrs(struct tcf_proto *tp, struct fw_filter *f,
 	}
 #endif /* CONFIG_NET_CLS_IND */
 
+	if (tb[TCA_FW_MASK-1]) {
+		if (RTA_PAYLOAD(tb[TCA_FW_MASK-1]) != sizeof(u32))
+			goto errout;
+		mask = *(u32*)RTA_DATA(tb[TCA_FW_MASK-1]);
+		if (mask != head->mask)
+			goto errout;
+	} else if (head->mask != 0xFFFFFFFF)
+		goto errout;
+
 	tcf_exts_change(tp, &f->exts, &e);
 
 	return 0;
@@ -267,9 +279,17 @@ static int fw_change(struct tcf_proto *tp, unsigned long base,
 		return -EINVAL;
 
 	if (head == NULL) {
+		u32 mask = 0xFFFFFFFF;
+		if (tb[TCA_FW_MASK-1]) {
+			if (RTA_PAYLOAD(tb[TCA_FW_MASK-1]) != sizeof(u32))
+				return -EINVAL;
+			mask = *(u32*)RTA_DATA(tb[TCA_FW_MASK-1]);
+		}
+
 		head = kzalloc(sizeof(struct fw_head), GFP_KERNEL);
 		if (head == NULL)
 			return -ENOBUFS;
+		head->mask = mask;
 
 		tcf_tree_lock(tp);
 		tp->root = head;
@@ -330,6 +350,7 @@ static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 static int fw_dump(struct tcf_proto *tp, unsigned long fh,
 		   struct sk_buff *skb, struct tcmsg *t)
 {
+	struct fw_head *head = (struct fw_head *)tp->root;
 	struct fw_filter *f = (struct fw_filter*)fh;
 	unsigned char	 *b = skb->tail;
 	struct rtattr *rta;
@@ -351,6 +372,8 @@ static int fw_dump(struct tcf_proto *tp, unsigned long fh,
 	if (strlen(f->indev))
 		RTA_PUT(skb, TCA_FW_INDEV, IFNAMSIZ, f->indev);
 #endif /* CONFIG_NET_CLS_IND */
+	if (head->mask != 0xFFFFFFFF)
+		RTA_PUT(skb, TCA_FW_MASK, 4, &head->mask);
 
 	if (tcf_exts_dump(skb, &f->exts, &fw_ext_map) < 0)
 		goto rtattr_failure;