net_sched: flower: Avoid dissection of unmasked keys

The current flower implementation checks the mask range and set all the
keys included in that range as "used_keys", even if a specific key in
the range has a zero mask.

This behavior can cause a false positive return value of
dissector_uses_key function and unnecessary dissection in
__skb_flow_dissect.

This patch checks explicitly the mask of each key and "used_keys" will
be set accordingly.

Fixes: 77b9900ef53a ('tc: introduce Flower classifier')
Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c
index 5060801a2f6db6f24d3d31f7b182cb72b072aa4a..0080fc0730198c8d6fe95836be34445afbcc7c46 100644 (file)
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -404,12 +404,10 @@ static int fl_init_hashtable(struct cls_fl_head *head,
 
 #define FL_KEY_MEMBER_OFFSET(member) offsetof(struct fl_flow_key, member)
 #define FL_KEY_MEMBER_SIZE(member) (sizeof(((struct fl_flow_key *) 0)->member))
-#define FL_KEY_MEMBER_END_OFFSET(member)                                       \
-       (FL_KEY_MEMBER_OFFSET(member) + FL_KEY_MEMBER_SIZE(member))
 
-#define FL_KEY_IN_RANGE(mask, member)                                          \
-        (FL_KEY_MEMBER_OFFSET(member) <= (mask)->range.end &&                  \
-         FL_KEY_MEMBER_END_OFFSET(member) >= (mask)->range.start)
+#define FL_KEY_IS_MASKED(mask, member)                                         \
+       memchr_inv(((char *)mask) + FL_KEY_MEMBER_OFFSET(member),               \
+                  0, FL_KEY_MEMBER_SIZE(member))                               \
 
 #define FL_KEY_SET(keys, cnt, id, member)                                      \
        do {                                                                    \
@@ -418,9 +416,9 @@ static int fl_init_hashtable(struct cls_fl_head *head,
                cnt++;                                                          \
        } while(0);
 
-#define FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt, id, member)                    \
+#define FL_KEY_SET_IF_MASKED(mask, keys, cnt, id, member)                      \
        do {                                                                    \
-               if (FL_KEY_IN_RANGE(mask, member))                              \
+               if (FL_KEY_IS_MASKED(mask, member))                             \
                        FL_KEY_SET(keys, cnt, id, member);                      \
        } while(0);
 
@@ -432,14 +430,14 @@ static void fl_init_dissector(struct cls_fl_head *head,
 
        FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_CONTROL, control);
        FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_BASIC, basic);
-       FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,
-                              FLOW_DISSECTOR_KEY_ETH_ADDRS, eth);
-       FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,
-                              FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4);
-       FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,
-                              FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6);
-       FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,
-                              FLOW_DISSECTOR_KEY_PORTS, tp);
+       FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
+                            FLOW_DISSECTOR_KEY_ETH_ADDRS, eth);
+       FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
+                            FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4);
+       FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
+                            FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6);
+       FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,
+                            FLOW_DISSECTOR_KEY_PORTS, tp);
 
        skb_flow_dissector_init(&head->dissector, keys, cnt);
 }