[IPV4]: Add support for fwmark masks in routing rules

Add a FRA_FWMASK attributes for fwmark masks. For compatibility a mask of
0xFFFFFFFF is used when a mark value != 0 is sent without a mask.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 3 deletions

diff --git a/include/linux/fib_rules.h b/include/linux/fib_rules.h
index 2987549d6044..4418c8d9d479 100644
--- a/include/linux/fib_rules.h
+++ b/include/linux/fib_rules.h
@@ -34,12 +34,13 @@ enum
         FRA_UNUSED3,
         FRA_UNUSED4,
         FRA_UNUSED5,
-        FRA_FWMARK,     /* netfilter mark (IPv4/IPv6) */
+        FRA_FWMARK,     /* netfilter mark */
         FRA_FLOW,       /* flow/class id */
         FRA_UNUSED6,
         FRA_UNUSED7,
         FRA_UNUSED8,
         FRA_TABLE,      /* Extended table id */
+        FRA_FWMASK,     /* mask for netfilter mark */
         __FRA_MAX
 };
 
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index ce185ac6f260..280f424ca9c9 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -46,6 +46,7 @@ struct fib4_rule
         u32                     dstmask;
 #ifdef CONFIG_IP_ROUTE_FWMARK
         u32                     fwmark;
+        u32                     fwmask;
 #endif
 #ifdef CONFIG_NET_CLS_ROUTE
         u32                     tclassid;
@@ -160,7 +161,7 @@ static int fib4_rule_match(struct fib_rule *rule, struct flowi *fl, int flags)
                 return 0;
 
 #ifdef CONFIG_IP_ROUTE_FWMARK
-        if (r->fwmark && (r->fwmark != fl->fl4_fwmark))
+        if ((r->fwmark ^ fl->fl4_fwmark) & r->fwmask)
                 return 0;
 #endif
 
@@ -183,6 +184,7 @@ static struct nla_policy fib4_rule_policy[FRA_MAX+1] __read_mostly = {
         [FRA_SRC]       = { .type = NLA_U32 },
         [FRA_DST]       = { .type = NLA_U32 },
         [FRA_FWMARK]    = { .type = NLA_U32 },
+        [FRA_FWMASK]    = { .type = NLA_U32 },
         [FRA_FLOW]      = { .type = NLA_U32 },
         [FRA_TABLE]     = { .type = NLA_U32 },
 };
@@ -219,8 +221,17 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
                 rule4->dst = nla_get_u32(tb[FRA_DST]);
 
 #ifdef CONFIG_IP_ROUTE_FWMARK
-        if (tb[FRA_FWMARK])
+        if (tb[FRA_FWMARK]) {
                 rule4->fwmark = nla_get_u32(tb[FRA_FWMARK]);
+                if (rule4->fwmark)
+                        /* compatibility: if the mark value is non-zero all bits
+                         * are compared unless a mask is explicitly specified.
+                         */
+                        rule4->fwmask = 0xFFFFFFFF;
+        }
+
+        if (tb[FRA_FWMASK])
+                rule4->fwmask = nla_get_u32(tb[FRA_FWMASK]);
 #endif
 
 #ifdef CONFIG_NET_CLS_ROUTE
@@ -256,6 +267,9 @@ static int fib4_rule_compare(struct fib_rule *rule, struct fib_rule_hdr *frh,
 #ifdef CONFIG_IP_ROUTE_FWMARK
         if (tb[FRA_FWMARK] && (rule4->fwmark != nla_get_u32(tb[FRA_FWMARK])))
                 return 0;
+
+        if (tb[FRA_FWMASK] && (rule4->fwmask != nla_get_u32(tb[FRA_FWMASK])))
+                return 0;
 #endif
 
 #ifdef CONFIG_NET_CLS_ROUTE
@@ -285,6 +299,9 @@ static int fib4_rule_fill(struct fib_rule *rule, struct sk_buff *skb,
 #ifdef CONFIG_IP_ROUTE_FWMARK
         if (rule4->fwmark)
                 NLA_PUT_U32(skb, FRA_FWMARK, rule4->fwmark);
+
+        if (rule4->fwmask || rule4->fwmark)
+                NLA_PUT_U32(skb, FRA_FWMASK, rule4->fwmask);
 #endif
 
         if (rule4->dst_len)