netfilter: nf_tables: make chain types override the default AF functions

Currently the AF-specific hook functions override the chain-type specific
hook functions. That doesn't make too much sense since the chain types
are a special case of the AF-specific hooks.

Make the AF-specific hook functions the default and make the optional
chain type hooks override them.

As a side effect, the necessary code restructuring reduces the code size,
f.i. in case of nf_tables_ipv4.o:

  nf_tables_ipv4_init_net   |  -24
  nft_do_chain_ipv4         | -113
 2 functions changed, 137 bytes removed, diff: -137

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

5 files changed, 81 insertions, 96 deletions

diff --git a/net/bridge/netfilter/nf_tables_bridge.c b/net/bridge/netfilter/nf_tables_bridge.c
index cf54b22818c8..c5fdd9a693be 100644
--- a/net/bridge/netfilter/nf_tables_bridge.c
+++ b/net/bridge/netfilter/nf_tables_bridge.c
@@ -14,10 +14,29 @@
 #include <linux/netfilter_bridge.h>
 #include <net/netfilter/nf_tables.h>
 
+static unsigned int
+nft_do_chain_bridge(const struct nf_hook_ops *ops,
+                    struct sk_buff *skb,
+                    const struct net_device *in,
+                    const struct net_device *out,
+                    int (*okfn)(struct sk_buff *))
+{
+        struct nft_pktinfo pkt;
+
+        nft_set_pktinfo(&pkt, ops, skb, in, out);
+
+        return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static struct nft_af_info nft_af_bridge __read_mostly = {
         .family         = NFPROTO_BRIDGE,
         .nhooks         = NF_BR_NUMHOOKS,
         .owner          = THIS_MODULE,
+        .hooks          = {
+                [NF_BR_LOCAL_IN]        = nft_do_chain_bridge,
+                [NF_BR_FORWARD]         = nft_do_chain_bridge,
+                [NF_BR_LOCAL_OUT]       = nft_do_chain_bridge,
+        },
 };
 
 static int nf_tables_bridge_init_net(struct net *net)
@@ -48,20 +67,6 @@ static struct pernet_operations nf_tables_bridge_net_ops = {
         .exit   = nf_tables_bridge_exit_net,
 };
 
-static unsigned int
-nft_do_chain_bridge(const struct nf_hook_ops *ops,
-                    struct sk_buff *skb,
-                    const struct net_device *in,
-                    const struct net_device *out,
-                    int (*okfn)(struct sk_buff *))
-{
-        struct nft_pktinfo pkt;
-
-        nft_set_pktinfo(&pkt, ops, skb, in, out);
-
-        return nft_do_chain_pktinfo(&pkt, ops);
-}
-
 static struct nf_chain_type filter_bridge = {
         .family         = NFPROTO_BRIDGE,
         .name           = "filter",
@@ -69,11 +74,6 @@ static struct nf_chain_type filter_bridge = {
         .hook_mask      = (1 << NF_BR_LOCAL_IN) |
                           (1 << NF_BR_FORWARD) |
                           (1 << NF_BR_LOCAL_OUT),
-        .fn             = {
-                [NF_BR_LOCAL_IN]        = nft_do_chain_bridge,
-                [NF_BR_FORWARD]         = nft_do_chain_bridge,
-                [NF_BR_LOCAL_OUT]       = nft_do_chain_bridge,
-        },
 };
 
 static int __init nf_tables_bridge_init(void)
diff --git a/net/ipv4/netfilter/nf_tables_arp.c b/net/ipv4/netfilter/nf_tables_arp.c
index 3e67ef1c676f..31bb778cebb8 100644
--- a/net/ipv4/netfilter/nf_tables_arp.c
+++ b/net/ipv4/netfilter/nf_tables_arp.c
@@ -14,10 +14,29 @@
 #include <linux/netfilter_arp.h>
 #include <net/netfilter/nf_tables.h>
 
+static unsigned int
+nft_do_chain_arp(const struct nf_hook_ops *ops,
+                  struct sk_buff *skb,
+                  const struct net_device *in,
+                  const struct net_device *out,
+                  int (*okfn)(struct sk_buff *))
+{
+        struct nft_pktinfo pkt;
+
+        nft_set_pktinfo(&pkt, ops, skb, in, out);
+
+        return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static struct nft_af_info nft_af_arp __read_mostly = {
         .family         = NFPROTO_ARP,
         .nhooks         = NF_ARP_NUMHOOKS,
         .owner          = THIS_MODULE,
+        .hooks          = {
+                [NF_ARP_IN]             = nft_do_chain_arp,
+                [NF_ARP_OUT]            = nft_do_chain_arp,
+                [NF_ARP_FORWARD]        = nft_do_chain_arp,
+        },
 };
 
 static int nf_tables_arp_init_net(struct net *net)
@@ -48,20 +67,6 @@ static struct pernet_operations nf_tables_arp_net_ops = {
         .exit   = nf_tables_arp_exit_net,
 };
 
-static unsigned int
-nft_do_chain_arp(const struct nf_hook_ops *ops,
-                  struct sk_buff *skb,
-                  const struct net_device *in,
-                  const struct net_device *out,
-                  int (*okfn)(struct sk_buff *))
-{
-        struct nft_pktinfo pkt;
-
-        nft_set_pktinfo(&pkt, ops, skb, in, out);
-
-        return nft_do_chain_pktinfo(&pkt, ops);
-}
-
 static struct nf_chain_type filter_arp = {
         .family         = NFPROTO_ARP,
         .name           = "filter",
@@ -69,11 +74,6 @@ static struct nf_chain_type filter_arp = {
         .hook_mask      = (1 << NF_ARP_IN) |
                           (1 << NF_ARP_OUT) |
                           (1 << NF_ARP_FORWARD),
-        .fn             = {
-                [NF_ARP_IN]             = nft_do_chain_arp,
-                [NF_ARP_OUT]            = nft_do_chain_arp,
-                [NF_ARP_FORWARD]        = nft_do_chain_arp,
-        },
 };
 
 static int __init nf_tables_arp_init(void)
diff --git a/net/ipv4/netfilter/nf_tables_ipv4.c b/net/ipv4/netfilter/nf_tables_ipv4.c
index 0f4cbfeb19bd..ed7e15a93410 100644
--- a/net/ipv4/netfilter/nf_tables_ipv4.c
+++ b/net/ipv4/netfilter/nf_tables_ipv4.c
@@ -18,14 +18,25 @@
 #include <net/ip.h>
 #include <net/netfilter/nf_tables_ipv4.h>
 
+static unsigned int nft_do_chain_ipv4(const struct nf_hook_ops *ops,
+                                      struct sk_buff *skb,
+                                      const struct net_device *in,
+                                      const struct net_device *out,
+                                      int (*okfn)(struct sk_buff *))
+{
+        struct nft_pktinfo pkt;
+
+        nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
+
+        return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
                                     struct sk_buff *skb,
                                     const struct net_device *in,
                                     const struct net_device *out,
                                     int (*okfn)(struct sk_buff *))
 {
-        struct nft_pktinfo pkt;
-
         if (unlikely(skb->len < sizeof(struct iphdr) ||
                      ip_hdr(skb)->ihl < sizeof(struct iphdr) / 4)) {
                 if (net_ratelimit())
@@ -33,9 +44,8 @@ static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
                                 "packet\n");
                 return NF_ACCEPT;
         }
-        nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
 
-        return nft_do_chain_pktinfo(&pkt, ops);
+        return nft_do_chain_ipv4(ops, skb, in, out, okfn);
 }
 
 static struct nft_af_info nft_af_ipv4 __read_mostly = {
@@ -43,7 +53,11 @@ static struct nft_af_info nft_af_ipv4 __read_mostly = {
         .nhooks         = NF_INET_NUMHOOKS,
         .owner          = THIS_MODULE,
         .hooks          = {
+                [NF_INET_LOCAL_IN]      = nft_do_chain_ipv4,
                 [NF_INET_LOCAL_OUT]     = nft_ipv4_output,
+                [NF_INET_FORWARD]       = nft_do_chain_ipv4,
+                [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv4,
+                [NF_INET_POST_ROUTING]  = nft_do_chain_ipv4,
         },
 };
 
@@ -75,20 +89,6 @@ static struct pernet_operations nf_tables_ipv4_net_ops = {
         .exit   = nf_tables_ipv4_exit_net,
 };
 
-static unsigned int
-nft_do_chain_ipv4(const struct nf_hook_ops *ops,
-                  struct sk_buff *skb,
-                  const struct net_device *in,
-                  const struct net_device *out,
-                  int (*okfn)(struct sk_buff *))
-{
-        struct nft_pktinfo pkt;
-
-        nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
-
-        return nft_do_chain_pktinfo(&pkt, ops);
-}
-
 static struct nf_chain_type filter_ipv4 = {
         .family         = NFPROTO_IPV4,
         .name           = "filter",
@@ -98,13 +98,6 @@ static struct nf_chain_type filter_ipv4 = {
                           (1 << NF_INET_FORWARD) |
                           (1 << NF_INET_PRE_ROUTING) |
                           (1 << NF_INET_POST_ROUTING),
-        .fn             = {
-                [NF_INET_LOCAL_IN]      = nft_do_chain_ipv4,
-                [NF_INET_LOCAL_OUT]     = nft_ipv4_output,
-                [NF_INET_FORWARD]       = nft_do_chain_ipv4,
-                [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv4,
-                [NF_INET_POST_ROUTING]  = nft_do_chain_ipv4,
-        },
 };
 
 static int __init nf_tables_ipv4_init(void)
diff --git a/net/ipv6/netfilter/nf_tables_ipv6.c b/net/ipv6/netfilter/nf_tables_ipv6.c
index d77db8a13505..54a2bcdc8a17 100644
--- a/net/ipv6/netfilter/nf_tables_ipv6.c
+++ b/net/ipv6/netfilter/nf_tables_ipv6.c
@@ -16,24 +16,35 @@
 #include <net/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_ipv6.h>
 
+static unsigned int nft_do_chain_ipv6(const struct nf_hook_ops *ops,
+                                      struct sk_buff *skb,
+                                      const struct net_device *in,
+                                      const struct net_device *out,
+                                      int (*okfn)(struct sk_buff *))
+{
+        struct nft_pktinfo pkt;
+
+        /* malformed packet, drop it */
+        if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
+                return NF_DROP;
+
+        return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static unsigned int nft_ipv6_output(const struct nf_hook_ops *ops,
                                     struct sk_buff *skb,
                                     const struct net_device *in,
                                     const struct net_device *out,
                                     int (*okfn)(struct sk_buff *))
 {
-        struct nft_pktinfo pkt;
-
         if (unlikely(skb->len < sizeof(struct ipv6hdr))) {
                 if (net_ratelimit())
                         pr_info("nf_tables_ipv6: ignoring short SOCK_RAW "
                                 "packet\n");
                 return NF_ACCEPT;
         }
-        if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
-                return NF_DROP;
 
-        return nft_do_chain_pktinfo(&pkt, ops);
+        return nft_do_chain_ipv6(ops, skb, in, out, okfn);
 }
 
 static struct nft_af_info nft_af_ipv6 __read_mostly = {
@@ -41,7 +52,11 @@ static struct nft_af_info nft_af_ipv6 __read_mostly = {
         .nhooks         = NF_INET_NUMHOOKS,
         .owner          = THIS_MODULE,
         .hooks          = {
+                [NF_INET_LOCAL_IN]      = nft_do_chain_ipv6,
                 [NF_INET_LOCAL_OUT]     = nft_ipv6_output,
+                [NF_INET_FORWARD]       = nft_do_chain_ipv6,
+                [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv6,
+                [NF_INET_POST_ROUTING]  = nft_do_chain_ipv6,
         },
 };
 
@@ -73,22 +88,6 @@ static struct pernet_operations nf_tables_ipv6_net_ops = {
         .exit   = nf_tables_ipv6_exit_net,
 };
 
-static unsigned int
-nft_do_chain_ipv6(const struct nf_hook_ops *ops,
-                  struct sk_buff *skb,
-                  const struct net_device *in,
-                  const struct net_device *out,
-                  int (*okfn)(struct sk_buff *))
-{
-        struct nft_pktinfo pkt;
-
-        /* malformed packet, drop it */
-        if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
-                return NF_DROP;
-
-        return nft_do_chain_pktinfo(&pkt, ops);
-}
-
 static struct nf_chain_type filter_ipv6 = {
         .family         = NFPROTO_IPV6,
         .name           = "filter",
@@ -98,13 +97,6 @@ static struct nf_chain_type filter_ipv6 = {
                           (1 << NF_INET_FORWARD) |
                           (1 << NF_INET_PRE_ROUTING) |
                           (1 << NF_INET_POST_ROUTING),
-        .fn             = {
-                [NF_INET_LOCAL_IN]      = nft_do_chain_ipv6,
-                [NF_INET_LOCAL_OUT]     = nft_ipv6_output,
-                [NF_INET_FORWARD]       = nft_do_chain_ipv6,
-                [NF_INET_PRE_ROUTING]   = nft_do_chain_ipv6,
-                [NF_INET_POST_ROUTING]  = nft_do_chain_ipv6,
-        },
 };
 
 static int __init nf_tables_ipv6_init(void)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1fcef1ec1dc1..d568626bc0f9 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -927,9 +927,9 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
                 if (hooknum >= afi->nhooks)
                         return -EINVAL;
 
-                hookfn = chain_type[family][type]->fn[hooknum];
-                if (hookfn == NULL)
+                if (!(chain_type[family][type]->hook_mask & (1 << hooknum)))
                         return -EOPNOTSUPP;
+                hookfn = chain_type[family][type]->fn[hooknum];
 
                 basechain = kzalloc(sizeof(*basechain), GFP_KERNEL);
                 if (basechain == NULL)
@@ -944,9 +944,9 @@ static int nf_tables_newchain(struct sock *nlsk, struct sk_buff *skb,
                 ops->hooknum    = ntohl(nla_get_be32(ha[NFTA_HOOK_HOOKNUM]));
                 ops->priority   = ntohl(nla_get_be32(ha[NFTA_HOOK_PRIORITY]));
                 ops->priv       = chain;
-                ops->hook       = hookfn;
-                if (afi->hooks[ops->hooknum])
-                        ops->hook = afi->hooks[ops->hooknum];
+                ops->hook       = afi->hooks[ops->hooknum];
+                if (hookfn)
+                        ops->hook = hookfn;
 
                 chain->flags |= NFT_BASE_CHAIN;