+/* Call this before modifying an existing packet: ensures it is
+ modifiable and linear to the point you care about (writable_len).
+ Returns true or false. */
+extern int skb_make_writable(struct sk_buff **pskb, unsigned int writable_len);
+
+static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
+{
+ __be32 diff[] = { ~from, to };
+
+ *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
+}
+
+static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to)
+{
+ nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to);
+}
+
+extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
+ __be32 from, __be32 to, int pseudohdr);
+
+static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
+ __be16 from, __be16 to, int pseudohdr)
+{
+ nf_proto_csum_replace4(sum, skb, (__force __be32)from,
+ (__force __be32)to, pseudohdr);
+}
+
+struct nf_afinfo {
+ unsigned short family;
+ __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
+ unsigned int dataoff, u_int8_t protocol);
+ void (*saveroute)(const struct sk_buff *skb,
+ struct nf_info *info);
+ int (*reroute)(struct sk_buff **skb,
+ const struct nf_info *info);
+ int route_key_size;
+};
+
+extern struct nf_afinfo *nf_afinfo[];
+static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
+{
+ 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)
+{
+ 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;
+}
+
+extern int nf_register_afinfo(struct nf_afinfo *afinfo);
+extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
+
+#define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
+
+#include <net/flow.h>
+extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
+
+static inline void
+nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
+{
+#if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
+ void (*decodefn)(struct sk_buff *, struct flowi *);
+
+ if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
+ decodefn(skb, fl);
+#endif
+}
+
+#ifdef CONFIG_PROC_FS
+#include <linux/proc_fs.h>
+extern struct proc_dir_entry *proc_net_netfilter;
+#endif
+