/* 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 inet_sock
 *
 * Authors:     Many, reorganised here by
 *              Arnaldo Carvalho de Melo <acme@mandriva.com>
 */
#ifndef _INET_SOCK_H
#define _INET_SOCK_H

#include <linux/bitops.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/jhash.h>
#include <linux/netdevice.h>

#include <net/flow.h>
#include <net/inet_dscp.h>
#include <net/sock.h>
#include <net/request_sock.h>
#include <net/netns/hash.h>
#include <net/tcp_states.h>
#include <net/l3mdev.h>

#define IP_OPTIONS_DATA_FIXED_SIZE 40

/** struct ip_options - IP Options
 *
 * @faddr - Saved first hop address
 * @nexthop - Saved nexthop address in LSRR and SSRR
 * @is_strictroute - Strict source route
 * @srr_is_hit - Packet destination addr was our one
 * @is_changed - IP checksum more not valid
 * @rr_needaddr - Need to record addr of outgoing dev
 * @ts_needtime - Need to record timestamp
 * @ts_needaddr - Need to record addr of outgoing dev
 */
struct ip_options {
        __be32          faddr;
        __be32          nexthop;
        unsigned char   optlen;
        unsigned char   srr;
        unsigned char   rr;
        unsigned char   ts;
        unsigned char   is_strictroute:1,
                        srr_is_hit:1,
                        is_changed:1,
                        rr_needaddr:1,
                        ts_needtime:1,
                        ts_needaddr:1;
        unsigned char   router_alert;
        unsigned char   cipso;
        unsigned char   __pad2;
        unsigned char   __data[];
};

struct ip_options_rcu {
        struct rcu_head rcu;

        /* Must be last as it ends in a flexible-array member. */
        struct ip_options opt;
};

struct inet_request_sock {
        struct request_sock     req;
#define ir_loc_addr             req.__req_common.skc_rcv_saddr
#define ir_rmt_addr             req.__req_common.skc_daddr
#define ir_num                  req.__req_common.skc_num
#define ir_rmt_port             req.__req_common.skc_dport
#define ir_v6_rmt_addr          req.__req_common.skc_v6_daddr
#define ir_v6_loc_addr          req.__req_common.skc_v6_rcv_saddr
#define ir_iif                  req.__req_common.skc_bound_dev_if
#define ir_cookie               req.__req_common.skc_cookie
#define ireq_net                req.__req_common.skc_net
#define ireq_state              req.__req_common.skc_state
#define ireq_family             req.__req_common.skc_family

        u16                     snd_wscale : 4,
                                rcv_wscale : 4,
                                tstamp_ok  : 1,
                                sack_ok    : 1,
                                wscale_ok  : 1,
                                ecn_ok     : 1,
                                acked      : 1,
                                no_srccheck: 1,
                                smc_ok     : 1;
        u32                     ir_mark;
        union {
                struct ip_options_rcu __rcu     *ireq_opt;
#if IS_ENABLED(CONFIG_IPV6)
                struct {
                        struct ipv6_txoptions   *ipv6_opt;
                        struct sk_buff          *pktopts;
                };
#endif
        };
};

#define inet_rsk(ptr) container_of_const(ptr, struct inet_request_sock, req)

static inline u32 inet_request_mark(const struct sock *sk, struct sk_buff *skb)
{
        u32 mark = READ_ONCE(sk->sk_mark);

        if (!mark && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_fwmark_accept))
                return skb->mark;

        return mark;
}

static inline int inet_request_bound_dev_if(const struct sock *sk,
                                            struct sk_buff *skb)
{
        int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
#ifdef CONFIG_NET_L3_MASTER_DEV
        struct net *net = sock_net(sk);

        if (!bound_dev_if && READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept))
                return l3mdev_master_ifindex_by_index(net, skb->skb_iif);
#endif

        return bound_dev_if;
}

static inline int inet_sk_bound_l3mdev(const struct sock *sk)
{
#ifdef CONFIG_NET_L3_MASTER_DEV
        struct net *net = sock_net(sk);

        if (!READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept))
                return l3mdev_master_ifindex_by_index(net,
                                                      sk->sk_bound_dev_if);
#endif

        return 0;
}

static inline bool inet_bound_dev_eq(bool l3mdev_accept, int bound_dev_if,
                                     int dif, int sdif)
{
        if (!bound_dev_if)
                return !sdif || l3mdev_accept;
        return bound_dev_if == dif || bound_dev_if == sdif;
}

static inline bool inet_sk_bound_dev_eq(const struct net *net,
                                        int bound_dev_if,
                                        int dif, int sdif)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
        return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_tcp_l3mdev_accept),
                                 bound_dev_if, dif, sdif);
#else
        return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
#endif
}

struct inet6_cork {
        struct ipv6_txoptions *opt;
        u8 hop_limit;
        u8 tclass;
        u8 dontfrag:1;
};

struct inet_cork {
        unsigned int            flags;
        __be32                  addr;
        struct ip_options       *opt;
        unsigned int            fragsize;
        int                     length; /* Total length of all frames */
        struct dst_entry        *dst;
        u8                      tx_flags;
        __u8                    ttl;
        __s16                   tos;
        u32                     priority;
        __u16                   gso_size;
        u32                     ts_opt_id;
        u64                     transmit_time;
        u32                     mark;
};

struct inet_cork_full {
        struct inet_cork        base;
        struct flowi            fl;
#if IS_ENABLED(CONFIG_IPV6)
        struct inet6_cork       base6;
#endif
};

struct ip_mc_socklist;
struct ipv6_pinfo;
struct rtable;

/** struct inet_sock - representation of INET sockets
 *
 * @sk - ancestor class
 * @pinet6 - pointer to IPv6 control block
 * @inet_daddr - Foreign IPv4 addr
 * @inet_rcv_saddr - Bound local IPv4 addr
 * @inet_dport - Destination port
 * @inet_num - Local port
 * @inet_flags - various atomic flags
 * @inet_saddr - Sending source
 * @uc_ttl - Unicast TTL
 * @inet_sport - Source port
 * @inet_id - ID counter for DF pkts
 * @tos - TOS
 * @mc_ttl - Multicasting TTL
 * @uc_index - Unicast outgoing device index
 * @mc_index - Multicast device index
 * @mc_list - Group array
 * @cork - info to build ip hdr on each ip frag while socket is corked
 */
struct inet_sock {
        /* sk and pinet6 has to be the first two members of inet_sock */
        struct sock             sk;
#if IS_ENABLED(CONFIG_IPV6)
        struct ipv6_pinfo       *pinet6;
        struct ipv6_fl_socklist __rcu *ipv6_fl_list;
#endif
        /* Socket demultiplex comparisons on incoming packets. */
#define inet_daddr              sk.__sk_common.skc_daddr
#define inet_rcv_saddr          sk.__sk_common.skc_rcv_saddr
#define inet_dport              sk.__sk_common.skc_dport
#define inet_num                sk.__sk_common.skc_num

        unsigned long           inet_flags;
        __be32                  inet_saddr;
        __s16                   uc_ttl;
        __be16                  inet_sport;
        struct ip_options_rcu __rcu     *inet_opt;
        atomic_t                inet_id;

        __u8                    tos;
        __u8                    min_ttl;
        __u8                    mc_ttl;
        __u8                    pmtudisc;
        __u8                    rcv_tos;
        __u8                    convert_csum;
        int                     uc_index;
        int                     mc_index;
        __be32                  mc_addr;
        u32                     local_port_range;       /* high << 16 | low */

        struct ip_mc_socklist __rcu     *mc_list;
        struct inet_cork_full   cork;
};

#define IPCORK_OPT              1       /* ip-options has been held in ipcork.opt */
#define IPCORK_TS_OPT_ID        2       /* ts_opt_id field is valid, overriding sk_tskey */

enum {
        INET_FLAGS_PKTINFO      = 0,
        INET_FLAGS_TTL          = 1,
        INET_FLAGS_TOS          = 2,
        INET_FLAGS_RECVOPTS     = 3,
        INET_FLAGS_RETOPTS      = 4,
        INET_FLAGS_PASSSEC      = 5,
        INET_FLAGS_ORIGDSTADDR  = 6,
        INET_FLAGS_CHECKSUM     = 7,
        INET_FLAGS_RECVFRAGSIZE = 8,

        INET_FLAGS_RECVERR      = 9,
        INET_FLAGS_RECVERR_RFC4884 = 10,
        INET_FLAGS_FREEBIND     = 11,
        INET_FLAGS_HDRINCL      = 12,
        INET_FLAGS_MC_LOOP      = 13,
        INET_FLAGS_MC_ALL       = 14,
        INET_FLAGS_TRANSPARENT  = 15,
        INET_FLAGS_IS_ICSK      = 16,
        INET_FLAGS_NODEFRAG     = 17,
        INET_FLAGS_BIND_ADDRESS_NO_PORT = 18,
        INET_FLAGS_DEFER_CONNECT = 19,
        INET_FLAGS_MC6_LOOP     = 20,
        INET_FLAGS_RECVERR6_RFC4884 = 21,
        INET_FLAGS_MC6_ALL      = 22,
        INET_FLAGS_AUTOFLOWLABEL_SET = 23,
        INET_FLAGS_AUTOFLOWLABEL = 24,
        INET_FLAGS_DONTFRAG     = 25,
        INET_FLAGS_RECVERR6     = 26,
        INET_FLAGS_REPFLOW      = 27,
        INET_FLAGS_RTALERT_ISOLATE = 28,
        INET_FLAGS_SNDFLOW      = 29,
        INET_FLAGS_RTALERT      = 30,
};

/* cmsg flags for inet */
#define IP_CMSG_PKTINFO         BIT(INET_FLAGS_PKTINFO)
#define IP_CMSG_TTL             BIT(INET_FLAGS_TTL)
#define IP_CMSG_TOS             BIT(INET_FLAGS_TOS)
#define IP_CMSG_RECVOPTS        BIT(INET_FLAGS_RECVOPTS)
#define IP_CMSG_RETOPTS         BIT(INET_FLAGS_RETOPTS)
#define IP_CMSG_PASSSEC         BIT(INET_FLAGS_PASSSEC)
#define IP_CMSG_ORIGDSTADDR     BIT(INET_FLAGS_ORIGDSTADDR)
#define IP_CMSG_CHECKSUM        BIT(INET_FLAGS_CHECKSUM)
#define IP_CMSG_RECVFRAGSIZE    BIT(INET_FLAGS_RECVFRAGSIZE)

#define IP_CMSG_ALL     (IP_CMSG_PKTINFO | IP_CMSG_TTL |                \
                         IP_CMSG_TOS | IP_CMSG_RECVOPTS |               \
                         IP_CMSG_RETOPTS | IP_CMSG_PASSSEC |            \
                         IP_CMSG_ORIGDSTADDR | IP_CMSG_CHECKSUM |       \
                         IP_CMSG_RECVFRAGSIZE)

static inline unsigned long inet_cmsg_flags(const struct inet_sock *inet)
{
        return READ_ONCE(inet->inet_flags) & IP_CMSG_ALL;
}

static inline dscp_t inet_sk_dscp(const struct inet_sock *inet)
{
        return inet_dsfield_to_dscp(READ_ONCE(inet->tos));
}

#define inet_test_bit(nr, sk)                   \
        test_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
#define inet_set_bit(nr, sk)                    \
        set_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
#define inet_clear_bit(nr, sk)                  \
        clear_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags)
#define inet_assign_bit(nr, sk, val)            \
        assign_bit(INET_FLAGS_##nr, &inet_sk(sk)->inet_flags, val)

/**
 * sk_to_full_sk - Access to a full socket
 * @sk: pointer to a socket
 *
 * SYNACK messages might be attached to request sockets.
 * Some places want to reach the listener in this case.
 */
static inline struct sock *sk_to_full_sk(struct sock *sk)
{
#ifdef CONFIG_INET
        if (sk && READ_ONCE(sk->sk_state) == TCP_NEW_SYN_RECV)
                sk = inet_reqsk(sk)->rsk_listener;
        if (sk && READ_ONCE(sk->sk_state) == TCP_TIME_WAIT)
                sk = NULL;
#endif
        return sk;
}

/* sk_to_full_sk() variant with a const argument */
static inline const struct sock *sk_const_to_full_sk(const struct sock *sk)
{
#ifdef CONFIG_INET
        if (sk && READ_ONCE(sk->sk_state) == TCP_NEW_SYN_RECV)
                sk = ((const struct request_sock *)sk)->rsk_listener;
        if (sk && READ_ONCE(sk->sk_state) == TCP_TIME_WAIT)
                sk = NULL;
#endif
        return sk;
}

static inline struct sock *skb_to_full_sk(const struct sk_buff *skb)
{
        return sk_to_full_sk(skb->sk);
}

#define inet_sk(ptr) container_of_const(ptr, struct inet_sock, sk)

int inet_sk_rebuild_header(struct sock *sk);

/**
 * inet_sk_state_load - read sk->sk_state for lockless contexts
 * @sk: socket pointer
 *
 * Paired with inet_sk_state_store(). Used in places we don't hold socket lock:
 * tcp_diag_get_info(), tcp_get_info(), tcp_poll(), get_tcp4_sock() ...
 */
static inline int inet_sk_state_load(const struct sock *sk)
{
        /* state change might impact lockless readers. */
        return smp_load_acquire(&sk->sk_state);
}

/**
 * inet_sk_state_store - update sk->sk_state
 * @sk: socket pointer
 * @newstate: new state
 *
 * Paired with inet_sk_state_load(). Should be used in contexts where
 * state change might impact lockless readers.
 */
void inet_sk_state_store(struct sock *sk, int newstate);

void inet_sk_set_state(struct sock *sk, int state);

static inline unsigned int __inet_ehashfn(const __be32 laddr,
                                          const __u16 lport,
                                          const __be32 faddr,
                                          const __be16 fport,
                                          u32 initval)
{
        return jhash_3words((__force __u32) laddr,
                            (__force __u32) faddr,
                            ((__u32) lport) << 16 | (__force __u32)fport,
                            initval);
}

struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
                                      struct sock *sk_listener,
                                      bool attach_listener);

static inline __u8 inet_sk_flowi_flags(const struct sock *sk)
{
        __u8 flags = 0;

        if (inet_test_bit(TRANSPARENT, sk) || inet_test_bit(HDRINCL, sk))
                flags |= FLOWI_FLAG_ANYSRC;
        return flags;
}

static inline void inet_inc_convert_csum(struct sock *sk)
{
        inet_sk(sk)->convert_csum++;
}

static inline void inet_dec_convert_csum(struct sock *sk)
{
        if (inet_sk(sk)->convert_csum > 0)
                inet_sk(sk)->convert_csum--;
}

static inline bool inet_get_convert_csum(struct sock *sk)
{
        return !!inet_sk(sk)->convert_csum;
}


static inline bool inet_can_nonlocal_bind(struct net *net,
                                          struct inet_sock *inet)
{
        return READ_ONCE(net->ipv4.sysctl_ip_nonlocal_bind) ||
                test_bit(INET_FLAGS_FREEBIND, &inet->inet_flags) ||
                test_bit(INET_FLAGS_TRANSPARENT, &inet->inet_flags);
}

static inline bool inet_addr_valid_or_nonlocal(struct net *net,
                                               struct inet_sock *inet,
                                               __be32 addr,
                                               int addr_type)
{
        return inet_can_nonlocal_bind(net, inet) ||
                addr == htonl(INADDR_ANY) ||
                addr_type == RTN_LOCAL ||
                addr_type == RTN_MULTICAST ||
                addr_type == RTN_BROADCAST;
}

#endif  /* _INET_SOCK_H */