From: Pablo Neira Ayuso Date: Mon, 27 Nov 2017 21:55:14 +0100 Subject: [PATCH] netfilter: move checksum indirection to struct nf_ipv6_ops We cannot make a direct call to nf_ip6_checksum() because that would result in autoloading the 'ipv6' module because of symbol dependencies. Therefore, define checksum 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 --- create mode 100644 net/netfilter/utils.c --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -311,8 +311,6 @@ struct nf_queue_entry; struct nf_afinfo { unsigned short family; - __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, @@ -333,20 +331,9 @@ static inline const struct nf_afinfo *nf return rcu_dereference(nf_afinfo[family]); } -static inline __sum16 -nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, - 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(skb, hook, dataoff, protocol); - rcu_read_unlock(); - return csum; -} +__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, + unsigned int dataoff, u_int8_t protocol, + unsigned short family); static inline __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, --- a/include/linux/netfilter_ipv4.h +++ b/include/linux/netfilter_ipv4.h @@ -7,6 +7,16 @@ #include int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned addr_type); + +#ifdef CONFIG_INET __sum16 nf_ip_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff, 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; +} +#endif /* CONFIG_INET */ + #endif /*__LINUX_IP_NETFILTER_H*/ --- a/include/linux/netfilter_ipv6.h +++ b/include/linux/netfilter_ipv6.h @@ -19,6 +19,8 @@ struct nf_ipv6_ops { void (*route_input)(struct sk_buff *skb); int (*fragment)(struct net *net, struct sock *sk, struct sk_buff *skb, 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); }; #ifdef CONFIG_NETFILTER --- a/net/bridge/netfilter/nf_tables_bridge.c +++ b/net/bridge/netfilter/nf_tables_bridge.c @@ -106,12 +106,6 @@ static int nf_br_reroute(struct net *net return 0; } -static __sum16 nf_br_checksum(struct sk_buff *skb, unsigned int hook, - unsigned int dataoff, u_int8_t protocol) -{ - 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) @@ -127,7 +121,6 @@ static int nf_br_route(struct net *net, static const struct nf_afinfo nf_br_afinfo = { .family = AF_BRIDGE, - .checksum = nf_br_checksum, .checksum_partial = nf_br_checksum_partial, .route = nf_br_route, .saveroute = nf_br_saveroute, --- a/net/ipv4/netfilter.c +++ b/net/ipv4/netfilter.c @@ -188,7 +188,6 @@ static int nf_ip_route(struct net *net, static const struct nf_afinfo nf_ip_afinfo = { .family = AF_INET, - .checksum = nf_ip_checksum, .checksum_partial = nf_ip_checksum_partial, .route = nf_ip_route, .saveroute = nf_ip_saveroute, --- a/net/ipv6/netfilter.c +++ b/net/ipv6/netfilter.c @@ -194,12 +194,12 @@ 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 + .fragment = ip6_fragment, + .checksum = nf_ip6_checksum, }; static const struct nf_afinfo nf_ip6_afinfo = { .family = AF_INET6, - .checksum = nf_ip6_checksum, .checksum_partial = nf_ip6_checksum_partial, .route = nf_ip6_route, .saveroute = nf_ip6_saveroute, --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o +netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o utils.o nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o nf_conntrack_acct.o nf_conntrack_seqadj.o nf_conntrack-$(CONFIG_NF_CONNTRACK_TIMEOUT) += nf_conntrack_timeout.o --- /dev/null +++ b/net/netfilter/utils.c @@ -0,0 +1,26 @@ +#include +#include +#include +#include + +__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, + unsigned int dataoff, 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(skb, hook, dataoff, protocol); + break; + case AF_INET6: + v6ops = rcu_dereference(nf_ipv6_ops); + if (v6ops) + csum = v6ops->checksum(skb, hook, dataoff, protocol); + break; + } + + return csum; +} +EXPORT_SYMBOL_GPL(nf_checksum);