/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * 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, <gw4pts@gw4pts.ampr.org>
 *
 * Changes:
 *              Mike McLagan    :       Routing by source
 */
#ifndef _IP_H
#define _IP_H

#include <linux/types.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/jhash.h>
#include <linux/sockptr.h>
#include <linux/static_key.h>

#include <net/inet_sock.h>
#include <net/route.h>
#include <net/snmp.h>
#include <net/flow.h>
#include <net/flow_dissector.h>
#include <net/netns/hash.h>
#include <net/lwtunnel.h>
#include <net/inet_dscp.h>

#define IPV4_MAX_PMTU           65535U          /* RFC 2675, Section 5.1 */
#define IPV4_MIN_MTU            68                      /* RFC 791 */

extern unsigned int sysctl_fib_sync_mem;
extern unsigned int sysctl_fib_sync_mem_min;
extern unsigned int sysctl_fib_sync_mem_max;

struct sock;

struct inet_skb_parm {
        int                     iif;
        struct ip_options       opt;            /* Compiled IP options          */
        u16                     flags;

#define IPSKB_FORWARDED         BIT(0)
#define IPSKB_XFRM_TUNNEL_SIZE  BIT(1)
#define IPSKB_XFRM_TRANSFORMED  BIT(2)
#define IPSKB_FRAG_COMPLETE     BIT(3)
#define IPSKB_REROUTED          BIT(4)
#define IPSKB_DOREDIRECT        BIT(5)
#define IPSKB_FRAG_PMTU         BIT(6)
#define IPSKB_L3SLAVE           BIT(7)
#define IPSKB_NOPOLICY          BIT(8)
#define IPSKB_MULTIPATH         BIT(9)
#define IPSKB_MCROUTE           BIT(10)

        u16                     frag_max_size;
};

static inline bool ipv4_l3mdev_skb(u16 flags)
{
        return !!(flags & IPSKB_L3SLAVE);
}

static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
{
        return ip_hdr(skb)->ihl * 4;
}

struct ipcm_cookie {
        struct sockcm_cookie    sockc;
        __be32                  addr;
        int                     oif;
        struct ip_options_rcu   *opt;
        __u8                    protocol;
        __u8                    ttl;
        __s16                   tos;
        __u16                   gso_size;
};

static inline void ipcm_init(struct ipcm_cookie *ipcm)
{
        *ipcm = (struct ipcm_cookie) { .tos = -1 };
}

static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
                                const struct inet_sock *inet)
{
        *ipcm = (struct ipcm_cookie) {
                .tos = READ_ONCE(inet->tos),
        };

        sockcm_init(&ipcm->sockc, &inet->sk);

        ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
        ipcm->addr = inet->inet_saddr;
        ipcm->protocol = READ_ONCE(inet->inet_num);
}

#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))

/* return enslaved device index if relevant */
static inline int inet_sdif(const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
        if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
                return IPCB(skb)->iif;
#endif
        return 0;
}

/* Special input handler for packets caught by router alert option.
   They are selected only by protocol field, and then processed likely
   local ones; but only if someone wants them! Otherwise, router
   not running rsvpd will kill RSVP.

   It is user level problem, what it will make with them.
   I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
   but receiver should be enough clever f.e. to forward mtrace requests,
   sent to multicast group to reach destination designated router.
 */

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;
};

/* 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, const struct sock *sk,
                          __be32 saddr, __be32 daddr,
                          struct ip_options_rcu *opt, u8 tos);
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
           struct net_device *orig_dev);
void ip_list_rcv(struct list_head *head, struct packet_type *pt,
                 struct net_device *orig_dev);
int ip_local_deliver(struct sk_buff *skb);
void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
int ip_mr_input(struct sk_buff *skb);
int ip_mr_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
                   int (*output)(struct net *, struct sock *, struct sk_buff *));

struct ip_fraglist_iter {
        struct sk_buff  *frag;
        struct iphdr    *iph;
        int             offset;
        unsigned int    hlen;
};

void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
                      unsigned int hlen, struct ip_fraglist_iter *iter);
void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);

static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
{
        struct sk_buff *skb = iter->frag;

        iter->frag = skb->next;
        skb_mark_not_on_list(skb);

        return skb;
}

struct ip_frag_state {
        bool            DF;
        unsigned int    hlen;
        unsigned int    ll_rs;
        unsigned int    mtu;
        unsigned int    left;
        int             offset;
        int             ptr;
        __be16          not_last_frag;
};

void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
                  unsigned int mtu, bool DF, struct ip_frag_state *state);
struct sk_buff *ip_frag_next(struct sk_buff *skb,
                             struct ip_frag_state *state);

void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);

int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
                    __u8 tos);
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);
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,
                            struct inet_cork *cork, unsigned int flags);

int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);

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);
}

/* Get the route scope that should be used when sending a packet. */
static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
                                  const struct ipcm_cookie *ipc,
                                  const struct msghdr *msg)
{
        if (sock_flag(&inet->sk, SOCK_LOCALROUTE) ||
            msg->msg_flags & MSG_DONTROUTE ||
            (ipc->opt && ipc->opt->opt.is_strictroute))
                return RT_SCOPE_LINK;

        return RT_SCOPE_UNIVERSE;
}

/* datagram.c */
int __ip4_datagram_connect(struct sock *sk, struct sockaddr_unsized *uaddr, int addr_len);
int ip4_datagram_connect(struct sock *sk, struct sockaddr_unsized *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;
        kuid_t      uid;
};

#define IP_REPLY_ARG_NOSRCCHECK 1

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 sock *sk, const struct sock *orig_sk,
                           struct sk_buff *skb,
                           const struct ip_options *sopt,
                           __be32 daddr, __be32 saddr,
                           const struct ip_reply_arg *arg,
                           unsigned int len, u64 transmit_time, u32 txhash);

#define IP_INC_STATS(net, field)        SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define __IP_INC_STATS(net, field)      __SNMP_INC_STATS64((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(net, field, val) __SNMP_ADD_STATS64((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(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
#define __NET_INC_STATS(net, field)     __SNMP_INC_STATS((net)->mib.net_statistics, field)
#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)

static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
{
        return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
}

unsigned long snmp_fold_field(void __percpu *mib, int offt);
#if BITS_PER_LONG==32
u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
                         size_t syncp_offset);
u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
#else
static inline u64  snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
                                        size_t syncp_offset)
{
        return snmp_get_cpu_field(mib, cpu, offct);

}

static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
{
        return snmp_fold_field(mib, offt);
}
#endif

#define snmp_get_cpu_field64_batch_cnt(buff64, stats_list, cnt, \
                                       mib_statistic, offset)   \
{ \
        int i, c; \
        for_each_possible_cpu(c) { \
                for (i = 0; i < cnt; i++) \
                        buff64[i] += snmp_get_cpu_field64( \
                                        mib_statistic, \
                                        c, stats_list[i].entry, \
                                        offset); \
        } \
}

#define snmp_get_cpu_field_batch_cnt(buff, stats_list, cnt, mib_statistic) \
{ \
        int i, c; \
        for_each_possible_cpu(c) { \
                for (i = 0; i < cnt; i++) \
                        buff[i] += snmp_get_cpu_field( \
                                                mib_statistic, \
                                                c, stats_list[i].entry); \
        } \
}

static inline void inet_get_local_port_range(const struct net *net, int *low, int *high)
{
        u32 range = READ_ONCE(net->ipv4.ip_local_ports.range);

        *low = range & 0xffff;
        *high = range >> 16;
}
bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);

#ifdef CONFIG_SYSCTL
static inline bool inet_is_local_reserved_port(const struct net *net, unsigned short port)
{
        if (!net->ipv4.sysctl_local_reserved_ports)
                return false;
        return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
}

static inline bool sysctl_dev_name_is_allowed(const char *name)
{
        return strcmp(name, "default") != 0  && strcmp(name, "all") != 0;
}

static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
        return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
}

#else
static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
{
        return false;
}

static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
        return port < PROT_SOCK;
}
#endif

__be32 inet_current_timestamp(void);

/* From inetpeer.c */
extern int inet_peer_threshold;
extern int inet_peer_minttl;
extern int inet_peer_maxttl;

void ipfrag_init(void);

void ip_static_sysctl_init(void);

#define IP4_REPLY_MARK(net, mark) \
        (READ_ONCE((net)->ipv4.sysctl_fwmark_reflect) ? (mark) : 0)

static inline bool ip_is_fragment(const struct iphdr *iph)
{
        return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
}

#ifdef CONFIG_INET
#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 dscp_t ip4h_dscp(const struct iphdr *ip4h)
{
        return inet_dsfield_to_dscp(ip4h->tos);
}

static inline int ip_mtu_locked(const struct dst_entry *dst)
{
        const struct rtable *rt = dst_rtable(dst);

        return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
}

static inline
int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
{
        u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);

        return  pmtudisc == IP_PMTUDISC_DO ||
                (pmtudisc == IP_PMTUDISC_WANT &&
                 !ip_mtu_locked(dst));
}

static inline bool ip_sk_accept_pmtu(const struct sock *sk)
{
        u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);

        return pmtudisc != IP_PMTUDISC_INTERFACE &&
               pmtudisc != IP_PMTUDISC_OMIT;
}

static inline bool ip_sk_use_pmtu(const struct sock *sk)
{
        return READ_ONCE(inet_sk(sk)->pmtudisc) < IP_PMTUDISC_PROBE;
}

static inline bool ip_sk_ignore_df(const struct sock *sk)
{
        u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);

        return pmtudisc < IP_PMTUDISC_DO || pmtudisc == IP_PMTUDISC_OMIT;
}

static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
                                                    bool forwarding)
{
        const struct rtable *rt = dst_rtable(dst);
        const struct net_device *dev;
        unsigned int mtu, res;
        struct net *net;

        rcu_read_lock();

        dev = dst_dev_rcu(dst);
        net = dev_net_rcu(dev);
        if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
            ip_mtu_locked(dst) ||
            !forwarding) {
                mtu = rt->rt_pmtu;
                if (mtu && time_before(jiffies, READ_ONCE(rt->dst.expires)))
                        goto out;
        }

        /* 'forwarding = true' case should always honour route mtu */
        mtu = dst_metric_raw(dst, RTAX_MTU);
        if (mtu)
                goto out;

        mtu = READ_ONCE(dev->mtu);

        if (unlikely(ip_mtu_locked(dst))) {
                if (rt->rt_uses_gateway && mtu > 576)
                        mtu = 576;
        }

out:
        mtu = min_t(unsigned int, mtu, IP_MAX_MTU);

        res = mtu - lwtunnel_headroom(dst->lwtstate, mtu);

        rcu_read_unlock();

        return res;
}

static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
                                          const struct sk_buff *skb)
{
        const struct dst_entry *dst = skb_dst(skb);
        unsigned int mtu;

        if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
                bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;

                return ip_dst_mtu_maybe_forward(dst, forwarding);
        }

        mtu = min(READ_ONCE(dst_dev(dst)->mtu), IP_MAX_MTU);
        return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
}

struct dst_metrics *ip_fib_metrics_init(struct nlattr *fc_mx, int fc_mx_len,
                                        struct netlink_ext_ack *extack);
static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
{
        if (fib_metrics != &dst_default_metrics &&
            refcount_dec_and_test(&fib_metrics->refcnt))
                kfree(fib_metrics);
}

/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
static inline
void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
{
        dst_init_metrics(dst, fib_metrics->metrics, true);

        if (fib_metrics != &dst_default_metrics) {
                dst->_metrics |= DST_METRICS_REFCOUNTED;
                refcount_inc(&fib_metrics->refcnt);
        }
}

static inline
void ip_dst_metrics_put(struct dst_entry *dst)
{
        struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);

        if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
                kfree(p);
}

void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);

static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
                                        struct sock *sk, int segs)
{
        struct iphdr *iph = ip_hdr(skb);

        /* We had many attacks based on IPID, use the private
         * generator as much as we can.
         */
        if (sk && inet_sk(sk)->inet_daddr) {
                int val;

                /* avoid atomic operations for TCP,
                 * as we hold socket lock at this point.
                 */
                if (sk_is_tcp(sk)) {
                        sock_owned_by_me(sk);
                        val = atomic_read(&inet_sk(sk)->inet_id);
                        atomic_set(&inet_sk(sk)->inet_id, val + segs);
                } else {
                        val = atomic_add_return(segs, &inet_sk(sk)->inet_id);
                }
                iph->id = htons(val);
                return;
        }
        if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
                iph->id = 0;
        } else {
                /* Unfortunately we need the big hammer to get a suitable IPID */
                __ip_select_ident(net, iph, segs);
        }
}

static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
                                   struct sock *sk)
{
        ip_select_ident_segs(net, skb, sk, 1);
}

static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
{
        return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
                                  skb->len, proto, 0);
}

/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
 * Equivalent to :      flow->v4addrs.src = iph->saddr;
 *                      flow->v4addrs.dst = iph->daddr;
 */
static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
                                            const struct iphdr *iph)
{
        BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
                     offsetof(typeof(flow->addrs), v4addrs.src) +
                              sizeof(flow->addrs.v4addrs.src));
        memcpy(&flow->addrs.v4addrs, &iph->addrs, sizeof(flow->addrs.v4addrs));
        flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
}

/*
 *      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);
        buf[0]=0x01;
        buf[1]=0x00;
        buf[2]=0x5e;
        buf[5]=addr&0xFF;
        addr>>=8;
        buf[4]=addr&0xFF;
        addr>>=8;
        buf[3]=addr&0x7F;
}

/*
 *      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);
        else
                memcpy(buf, &naddr, sizeof(naddr));
}

#if IS_ENABLED(CONFIG_IPV6)
#include <linux/ipv6.h>
#endif

static __inline__ void inet_reset_saddr(struct sock *sk)
{
        inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
#if IS_ENABLED(CONFIG_IPV6)
        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));
        }
#endif
}

#endif

#if IS_MODULE(CONFIG_IPV6)
#define EXPORT_IPV6_MOD(X) EXPORT_SYMBOL(X)
#define EXPORT_IPV6_MOD_GPL(X) EXPORT_SYMBOL_GPL(X)
#else
#define EXPORT_IPV6_MOD(X)
#define EXPORT_IPV6_MOD_GPL(X)
#endif

static inline unsigned int ipv4_addr_hash(__be32 ip)
{
        return (__force unsigned int) ip;
}

static inline u32 __ipv4_addr_hash(const __be32 ip, const u32 initval)
{
        return jhash_1word((__force u32)ip, initval);
}

static inline u32 ipv4_portaddr_hash(const struct net *net,
                                     __be32 saddr,
                                     unsigned int port)
{
        return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
}

bool ip_call_ra_chain(struct sk_buff *skb);

/*
 *      Functions provided by ip_fragment.c
 */

enum ip_defrag_users {
        IP_DEFRAG_LOCAL_DELIVER,
        IP_DEFRAG_CALL_RA_CHAIN,
        IP_DEFRAG_CONNTRACK_IN,
        __IP_DEFRAG_CONNTRACK_IN_END    = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
        IP_DEFRAG_CONNTRACK_OUT,
        __IP_DEFRAG_CONNTRACK_OUT_END   = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
        IP_DEFRAG_CONNTRACK_BRIDGE_IN,
        __IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
        IP_DEFRAG_VS_IN,
        IP_DEFRAG_VS_OUT,
        IP_DEFRAG_VS_FWD,
        IP_DEFRAG_AF_PACKET,
        IP_DEFRAG_MACVLAN,
};

/* Return true if the value of 'user' is between 'lower_bond'
 * and 'upper_bond' inclusively.
 */
static inline bool ip_defrag_user_in_between(u32 user,
                                             enum ip_defrag_users lower_bond,
                                             enum ip_defrag_users upper_bond)
{
        return user >= lower_bond && user <= upper_bond;
}

int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
#ifdef CONFIG_INET
struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
#else
static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
{
        return skb;
}
#endif

/*
 *      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 __ip_options_echo(struct net *net, struct ip_options *dopt,
                      struct sk_buff *skb, const struct ip_options *sopt);
static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
                                  struct sk_buff *skb)
{
        return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
}

void ip_options_fragment(struct sk_buff *skb);
int __ip_options_compile(struct net *net, struct ip_options *opt,
                         struct sk_buff *skb, __be32 *info);
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,
                   sockptr_t 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, struct net_device *dev);

/*
 *      Functions provided by ip_sockglue.c
 */

void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst);
void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
                         struct sk_buff *skb, int tlen, int offset);
int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
                 struct ipcm_cookie *ipc, bool allow_ipv6);
DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
                     unsigned int optlen);
int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
                  unsigned int optlen);
int do_ip_getsockopt(struct sock *sk, int level, int optname,
                     sockptr_t optval, sockptr_t optlen);
int 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);

static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
{
        ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
}

bool icmp_global_allow(struct net *net);
void icmp_global_consume(struct net *net);

#ifdef CONFIG_PROC_FS
int ip_misc_proc_init(void);
#endif

int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
                                struct netlink_ext_ack *extack);

static inline bool inetdev_valid_mtu(unsigned int mtu)
{
        return likely(mtu >= IPV4_MIN_MTU);
}

void ip_sock_set_freebind(struct sock *sk);
int ip_sock_set_mtu_discover(struct sock *sk, int val);
void ip_sock_set_pktinfo(struct sock *sk);
void ip_sock_set_recverr(struct sock *sk);
void ip_sock_set_tos(struct sock *sk, int val);
void  __ip_sock_set_tos(struct sock *sk, int val);

#endif  /* _IP_H */