[openwrt/openwrt.git] /

From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Wed, 20 Dec 2017 16:04:18 +0100
Subject: [PATCH] netfilter: move checksum_partial indirection to struct
 nf_ipv6_ops

We cannot make a direct call to nf_ip6_checksum_partial() because that
would result in autoloading the 'ipv6' module because of symbol
dependencies.  Therefore, define checksum_partial indirection in
nf_ipv6_ops where this really belongs to.

For IPv4, we can indeed make a direct function call, which is faster,
given IPv4 is built-in in the networking code by default. Still,
CONFIG_INET=n and CONFIG_NETFILTER=y is possible, so define empty inline
stub for IPv4 in such case.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -311,11 +311,6 @@ struct nf_queue_entry;
 
 struct nf_afinfo {
        unsigned short  family;
-       __sum16         (*checksum_partial)(struct sk_buff *skb,
-                                           unsigned int hook,
-                                           unsigned int dataoff,
-                                           unsigned int len,
-                                           u_int8_t protocol);
        int             (*route)(struct net *net, struct dst_entry **dst,
                                 struct flowi *fl, bool strict);
        void            (*saveroute)(const struct sk_buff *skb,
@@ -335,22 +330,9 @@ __sum16 nf_checksum(struct sk_buff *skb,
                    unsigned int dataoff, u_int8_t protocol,
                    unsigned short family);
 
-static inline __sum16
-nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
-                   unsigned int dataoff, unsigned int len,
-                   u_int8_t protocol, unsigned short family)
-{
-       const struct nf_afinfo *afinfo;
-       __sum16 csum = 0;
-
-       rcu_read_lock();
-       afinfo = nf_get_afinfo(family);
-       if (afinfo)
-               csum = afinfo->checksum_partial(skb, hook, dataoff, len,
-                                               protocol);
-       rcu_read_unlock();
-       return csum;
-}
+__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
+                           unsigned int dataoff, unsigned int len,
+                           u_int8_t protocol, unsigned short family);
 
 int nf_register_afinfo(const struct nf_afinfo *afinfo);
 void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
--- a/include/linux/netfilter_ipv4.h
+++ b/include/linux/netfilter_ipv4.h
@@ -11,12 +11,23 @@ int ip_route_me_harder(struct net *net,
 #ifdef CONFIG_INET
 __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
                       unsigned int dataoff, u_int8_t protocol);
+__sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
+                              unsigned int dataoff, unsigned int len,
+                              u_int8_t protocol);
 #else
 static inline __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
                                     unsigned int dataoff, u_int8_t protocol)
 {
        return 0;
 }
+static inline __sum16 nf_ip_checksum_partial(struct sk_buff *skb,
+                                            unsigned int hook,
+                                            unsigned int dataoff,
+                                            unsigned int len,
+                                            u_int8_t protocol)
+{
+       return 0;
+}
 #endif /* CONFIG_INET */
 
 #endif /*__LINUX_IP_NETFILTER_H*/
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -21,6 +21,9 @@ struct nf_ipv6_ops {
                        int (*output)(struct net *, struct sock *, struct sk_buff *));
        __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
                            unsigned int dataoff, u_int8_t protocol);
+       __sum16 (*checksum_partial)(struct sk_buff *skb, unsigned int hook,
+                                   unsigned int dataoff, unsigned int len,
+                                   u_int8_t protocol);
 };
 
 #ifdef CONFIG_NETFILTER
--- a/net/bridge/netfilter/nf_tables_bridge.c
+++ b/net/bridge/netfilter/nf_tables_bridge.c
@@ -106,13 +106,6 @@ static int nf_br_reroute(struct net *net
        return 0;
 }
 
-static __sum16 nf_br_checksum_partial(struct sk_buff *skb, unsigned int hook,
-                                     unsigned int dataoff, unsigned int len,
-                                     u_int8_t protocol)
-{
-       return 0;
-}
-
 static int nf_br_route(struct net *net, struct dst_entry **dst,
                       struct flowi *fl, bool strict __always_unused)
 {
@@ -121,7 +114,6 @@ static int nf_br_route(struct net *net,
 
 static const struct nf_afinfo nf_br_afinfo = {
        .family                 = AF_BRIDGE,
-       .checksum_partial       = nf_br_checksum_partial,
        .route                  = nf_br_route,
        .saveroute              = nf_br_saveroute,
        .reroute                = nf_br_reroute,
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -155,9 +155,9 @@ __sum16 nf_ip_checksum(struct sk_buff *s
 }
 EXPORT_SYMBOL(nf_ip_checksum);
 
-static __sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
-                                     unsigned int dataoff, unsigned int len,
-                                     u_int8_t protocol)
+__sum16 nf_ip_checksum_partial(struct sk_buff *skb, unsigned int hook,
+                              unsigned int dataoff, unsigned int len,
+                              u_int8_t protocol)
 {
        const struct iphdr *iph = ip_hdr(skb);
        __sum16 csum = 0;
@@ -175,6 +175,7 @@ static __sum16 nf_ip_checksum_partial(st
        }
        return csum;
 }
+EXPORT_SYMBOL_GPL(nf_ip_checksum_partial);
 
 static int nf_ip_route(struct net *net, struct dst_entry **dst,
                       struct flowi *fl, bool strict __always_unused)
@@ -188,7 +189,6 @@ static int nf_ip_route(struct net *net,
 
 static const struct nf_afinfo nf_ip_afinfo = {
        .family                 = AF_INET,
-       .checksum_partial       = nf_ip_checksum_partial,
        .route                  = nf_ip_route,
        .saveroute              = nf_ip_saveroute,
        .reroute                = nf_ip_reroute,
--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -194,15 +194,15 @@ static __sum16 nf_ip6_checksum_partial(s
 };
 
 static const struct nf_ipv6_ops ipv6ops = {
-       .chk_addr       = ipv6_chk_addr,
-       .route_input    = ip6_route_input,
-       .fragment       = ip6_fragment,
-       .checksum       = nf_ip6_checksum,
+       .chk_addr               = ipv6_chk_addr,
+       .route_input            = ip6_route_input,
+       .fragment               = ip6_fragment,
+       .checksum               = nf_ip6_checksum,
+       .checksum_partial       = nf_ip6_checksum_partial,
 };
 
 static const struct nf_afinfo nf_ip6_afinfo = {
        .family                 = AF_INET6,
-       .checksum_partial       = nf_ip6_checksum_partial,
        .route                  = nf_ip6_route,
        .saveroute              = nf_ip6_saveroute,
        .reroute                = nf_ip6_reroute,
--- a/net/netfilter/utils.c
+++ b/net/netfilter/utils.c
@@ -24,3 +24,27 @@ __sum16 nf_checksum(struct sk_buff *skb,
        return csum;
 }
 EXPORT_SYMBOL_GPL(nf_checksum);
+
+__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
+                           unsigned int dataoff, unsigned int len,
+                           u_int8_t protocol, unsigned short family)
+{
+       const struct nf_ipv6_ops *v6ops;
+       __sum16 csum = 0;
+
+       switch (family) {
+       case AF_INET:
+               csum = nf_ip_checksum_partial(skb, hook, dataoff, len,
+                                             protocol);
+               break;
+       case AF_INET6:
+               v6ops = rcu_dereference(nf_ipv6_ops);
+               if (v6ops)
+                       csum = v6ops->checksum_partial(skb, hook, dataoff, len,
+                                                      protocol);
+               break;
+       }
+
+       return csum;
+}
+EXPORT_SYMBOL_GPL(nf_checksum_partial);