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* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
* Definitions for the IP module.
* Version: @(#)ip.h 1.0.2 05/07/93
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Alan Cox, <>
* Changes:
* Mike McLagan : Routing by source
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
#ifndef _IP_H
#define _IP_H
#include <linux/types.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <net/inet_sock.h>
#include <net/route.h>
#include <net/snmp.h>
#include <net/flow.h>
struct sock;
struct inet_skb_parm {
struct ip_options opt; /* Compiled IP options */
unsigned char flags;
u16 frag_max_size;
static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
return ip_hdr(skb)->ihl * 4;
struct ipcm_cookie {
__be32 addr;
int oif;
struct ip_options_rcu *opt;
__u8 tx_flags;
__u8 ttl;
__s16 tos;
char priority;
#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
struct ip_ra_chain {
struct ip_ra_chain __rcu *next;
struct sock *sk;
union {
void (*destructor)(struct sock *);
struct sock *saved_sk;
struct rcu_head rcu;
extern struct ip_ra_chain __rcu *ip_ra_chain;
/* IP flags. */
#define IP_CE 0x8000 /* Flag: "Congestion" */
#define IP_DF 0x4000 /* Flag: "Don't Fragment" */
#define IP_MF 0x2000 /* Flag: "More Fragments" */
#define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
#define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
struct msghdr;
struct net_device;
struct packet_type;
struct rtable;
struct sockaddr;
int igmp_mc_init(void);
* Functions provided by ip.c
int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
__be32 saddr, __be32 daddr,
struct ip_options_rcu *opt);
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
struct net_device *orig_dev);
int ip_local_deliver(struct sk_buff *skb);
int ip_mr_input(struct sk_buff *skb);
int ip_output(struct sk_buff *skb);
int ip_mc_output(struct sk_buff *skb);
int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
int ip_do_nat(struct sk_buff *skb);
void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct sk_buff *skb);
int ip_local_out(struct sk_buff *skb);
int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
void ip_init(void);
int ip_append_data(struct sock *sk, struct flowi4 *fl4,
int getfrag(void *from, char *to, int offset, int len,
int odd, struct sk_buff *skb),
void *from, int len, int protolen,
struct ipcm_cookie *ipc,
struct rtable **rt,
unsigned int flags);
int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
struct sk_buff *skb);
ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
int offset, size_t size, int flags);
struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
struct sk_buff_head *queue,
struct inet_cork *cork);
int ip_send_skb(struct net *net, struct sk_buff *skb);
int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
void ip_flush_pending_frames(struct sock *sk);
struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
int getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb),
void *from, int length, int transhdrlen,
struct ipcm_cookie *ipc, struct rtable **rtp,
unsigned int flags);
static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(inet->tos);
static inline __u8 get_rtconn_flags(struct ipcm_cookie* ipc, struct sock* sk)
return (ipc->tos != -1) ? RT_CONN_FLAGS_TOS(sk, ipc->tos) : RT_CONN_FLAGS(sk);
/* datagram.c */
int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
void ip4_datagram_release_cb(struct sock *sk);
struct ip_reply_arg {
struct kvec iov[1];
int flags;
__wsum csum;
int csumoffset; /* u16 offset of csum in iov[0].iov_base */
/* -1 if not needed */
int bound_dev_if;
u8 tos;
static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr,
__be32 saddr, const struct ip_reply_arg *arg,
unsigned int len);
#define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define IP_INC_STATS_BH(net, field) SNMP_INC_STATS64_BH((net)->mib.ip_statistics, field)
#define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS64_BH((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS_BH(net, field, val) SNMP_UPD_PO_STATS64_BH((net)->mib.ip_statistics, field, val)
#define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
#define NET_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
#define NET_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
#define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
#define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
unsigned long snmp_fold_field(void __percpu *mib[], int offt);
u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t sync_off);
static inline u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_off)
return snmp_fold_field(mib, offt);
int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align);
static inline void snmp_mib_free(void __percpu *ptr[SNMP_ARRAY_SZ])
int i;
BUG_ON(ptr == NULL);
for (i = 0; i < SNMP_ARRAY_SZ; i++) {
ptr[i] = NULL;
void inet_get_local_port_range(struct net *net, int *low, int *high);
extern unsigned long *sysctl_local_reserved_ports;
static inline int inet_is_reserved_local_port(int port)
return test_bit(port, sysctl_local_reserved_ports);
extern int sysctl_ip_nonlocal_bind;
/* From inetpeer.c */
extern int inet_peer_threshold;
extern int inet_peer_minttl;
extern int inet_peer_maxttl;
/* From ip_input.c */
extern int sysctl_ip_early_demux;
/* From ip_output.c */
extern int sysctl_ip_dynaddr;
void ipfrag_init(void);
void ip_static_sysctl_init(void);
static inline bool ip_is_fragment(const struct iphdr *iph)
return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
#include <net/dst.h>
/* The function in 2.2 was invalid, producing wrong result for
* check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
static inline
int ip_decrease_ttl(struct iphdr *iph)
u32 check = (__force u32)iph->check;
check += (__force u32)htons(0x0100);
iph->check = (__force __sum16)(check + (check>=0xFFFF));
return --iph->ttl;
static inline
int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
return inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
(inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
!(dst_metric_locked(dst, RTAX_MTU)));
static inline bool ip_sk_accept_pmtu(const struct sock *sk)
return inet_sk(sk)->pmtudisc != IP_PMTUDISC_INTERFACE;
static inline bool ip_sk_use_pmtu(const struct sock *sk)
return inet_sk(sk)->pmtudisc < IP_PMTUDISC_PROBE;
static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
bool forwarding)
struct net *net = dev_net(dst->dev);
if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
dst_metric_locked(dst, RTAX_MTU) ||
return dst_mtu(dst);
return min(dst->dev->mtu, IP_MAX_MTU);
static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb)
if (!skb->sk || ip_sk_use_pmtu(skb->sk)) {
bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
} else {
return min(skb_dst(skb)->dev->mtu, IP_MAX_MTU);
u32 ip_idents_reserve(u32 hash, int segs);
void __ip_select_ident(struct iphdr *iph, int segs);
static inline void ip_select_ident_segs(struct sk_buff *skb, struct sock *sk, int segs)
struct iphdr *iph = ip_hdr(skb);
if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
/* This is only to work around buggy Windows95/2000
* VJ compression implementations. If the ID field
* does not change, they drop every other packet in
* a TCP stream using header compression.
if (sk && inet_sk(sk)->inet_daddr) {
iph->id = htons(inet_sk(sk)->inet_id);
inet_sk(sk)->inet_id += segs;
} else {
iph->id = 0;
} else {
__ip_select_ident(iph, segs);
static inline void ip_select_ident(struct sk_buff *skb, struct sock *sk)
ip_select_ident_segs(skb, sk, 1);
* Map a multicast IP onto multicast MAC for type ethernet.
static inline void ip_eth_mc_map(__be32 naddr, char *buf)
__u32 addr=ntohl(naddr);
* Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
* Leave P_Key as 0 to be filled in by driver.
static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
__u32 addr;
unsigned char scope = broadcast[5] & 0xF;
buf[0] = 0; /* Reserved */
buf[1] = 0xff; /* Multicast QPN */
buf[2] = 0xff;
buf[3] = 0xff;
addr = ntohl(naddr);
buf[4] = 0xff;
buf[5] = 0x10 | scope; /* scope from broadcast address */
buf[6] = 0x40; /* IPv4 signature */
buf[7] = 0x1b;
buf[8] = broadcast[8]; /* P_Key */
buf[9] = broadcast[9];
buf[10] = 0;
buf[11] = 0;
buf[12] = 0;
buf[13] = 0;
buf[14] = 0;
buf[15] = 0;
buf[19] = addr & 0xff;
addr >>= 8;
buf[18] = addr & 0xff;
addr >>= 8;
buf[17] = addr & 0xff;
addr >>= 8;
buf[16] = addr & 0x0f;
static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
memcpy(buf, broadcast, 4);
memcpy(buf, &naddr, sizeof(naddr));
#include <linux/ipv6.h>
static __inline__ void inet_reset_saddr(struct sock *sk)
inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
if (sk->sk_family == PF_INET6) {
struct ipv6_pinfo *np = inet6_sk(sk);
memset(&np->saddr, 0, sizeof(np->saddr));
memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
static inline int sk_mc_loop(struct sock *sk)
if (!sk)
return 1;
switch (sk->sk_family) {
case AF_INET:
return inet_sk(sk)->mc_loop;
case AF_INET6:
return inet6_sk(sk)->mc_loop;
return 1;
bool ip_call_ra_chain(struct sk_buff *skb);
* Functions provided by ip_fragment.c
enum ip_defrag_users {
int ip_defrag(struct sk_buff *skb, u32 user);
struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user);
static inline struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
return skb;
int ip_frag_mem(struct net *net);
int ip_frag_nqueues(struct net *net);
* Functions provided by ip_forward.c
int ip_forward(struct sk_buff *skb);
* Functions provided by ip_options.c
void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
__be32 daddr, struct rtable *rt, int is_frag);
int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
void ip_options_fragment(struct sk_buff *skb);
int ip_options_compile(struct net *net, struct ip_options *opt,
struct sk_buff *skb);
int ip_options_get(struct net *net, struct ip_options_rcu **optp,
unsigned char *data, int optlen);
int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
unsigned char __user *data, int optlen);
void ip_options_undo(struct ip_options *opt);
void ip_forward_options(struct sk_buff *skb);
int ip_options_rcv_srr(struct sk_buff *skb);
* Functions provided by ip_sockglue.c
void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb);
void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
int ip_cmsg_send(struct net *net, struct msghdr *msg, struct ipcm_cookie *ipc);
int ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
unsigned int optlen);
int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
int __user *optlen);
int compat_ip_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen);
int compat_ip_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen);
int ip_ra_control(struct sock *sk, unsigned char on,
void (*destructor)(struct sock *));
int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
u32 info, u8 *payload);
void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
u32 info);
int ip_misc_proc_init(void);
#endif /* _IP_H */