/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * NET          An implementation of the SOCKET network access protocol.
 *              This is the master header file for the Linux NET layer,
 *              or, in plain English: the networking handling part of the
 *              kernel.
 *
 * Version:     @(#)net.h       1.0.3   05/25/93
 *
 * Authors:     Orest Zborowski, <obz@Kodak.COM>
 *              Ross Biro
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 */
#ifndef _LINUX_NET_H
#define _LINUX_NET_H

#include <linux/stringify.h>
#include <linux/random.h>
#include <linux/wait.h>
#include <linux/fcntl.h>        /* For O_CLOEXEC and O_NONBLOCK */
#include <linux/rcupdate.h>
#include <linux/once.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sockptr.h>

#include <uapi/linux/net.h>

struct poll_table_struct;
struct pipe_inode_info;
struct inode;
struct file;
struct net;

/* Historically, SOCKWQ_ASYNC_NOSPACE & SOCKWQ_ASYNC_WAITDATA were located
 * in sock->flags, but moved into sk->sk_wq->flags to be RCU protected.
 * Eventually all flags will be in sk->sk_wq->flags.
 */
enum socket_flags {
        SOCKWQ_ASYNC_NOSPACE,
        SOCKWQ_ASYNC_WAITDATA,
        SOCK_NOSPACE,
        SOCK_SUPPORT_ZC,
        SOCK_CUSTOM_SOCKOPT,
};

#ifndef ARCH_HAS_SOCKET_TYPES
/**
 * enum sock_type - Socket types
 * @SOCK_STREAM: stream (connection) socket
 * @SOCK_DGRAM: datagram (conn.less) socket
 * @SOCK_RAW: raw socket
 * @SOCK_RDM: reliably-delivered message
 * @SOCK_SEQPACKET: sequential packet socket
 * @SOCK_DCCP: Datagram Congestion Control Protocol socket
 * @SOCK_PACKET: linux specific way of getting packets at the dev level.
 *                For writing rarp and other similar things on the user level.
 *
 * When adding some new socket type please
 * grep ARCH_HAS_SOCKET_TYPE include/asm-* /socket.h, at least MIPS
 * overrides this enum for binary compat reasons.
 */
enum sock_type {
        SOCK_STREAM     = 1,
        SOCK_DGRAM      = 2,
        SOCK_RAW        = 3,
        SOCK_RDM        = 4,
        SOCK_SEQPACKET  = 5,
        SOCK_DCCP       = 6,
        SOCK_PACKET     = 10,
};
#endif /* ARCH_HAS_SOCKET_TYPES */

#define SOCK_MAX (SOCK_PACKET + 1)
/* Mask which covers at least up to SOCK_MASK-1.  The
 * remaining bits are used as flags. */
#define SOCK_TYPE_MASK 0xf

/* Flags for socket, socketpair, accept4 */
#define SOCK_CLOEXEC    O_CLOEXEC
#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK   O_NONBLOCK
#endif
#define SOCK_COREDUMP   O_NOCTTY

/**
 * enum sock_shutdown_cmd - Shutdown types
 * @SHUT_RD: shutdown receptions
 * @SHUT_WR: shutdown transmissions
 * @SHUT_RDWR: shutdown receptions/transmissions
 */
enum sock_shutdown_cmd {
        SHUT_RD,
        SHUT_WR,
        SHUT_RDWR,
};

struct socket_wq {
        /* Note: wait MUST be first field of socket_wq */
        wait_queue_head_t       wait;
        struct fasync_struct    *fasync_list;
        unsigned long           flags; /* %SOCKWQ_ASYNC_NOSPACE, etc */
        struct rcu_head         rcu;
} ____cacheline_aligned_in_smp;

/**
 *  struct socket - general BSD socket
 *  @state: socket state (%SS_CONNECTED, etc)
 *  @type: socket type (%SOCK_STREAM, etc)
 *  @flags: socket flags (%SOCK_NOSPACE, etc)
 *  @ops: protocol specific socket operations
 *  @file: File back pointer for gc
 *  @sk: internal networking protocol agnostic socket representation
 *  @wq: wait queue for several uses
 */
struct socket {
        socket_state            state;

        short                   type;

        unsigned long           flags;

        struct file             *file;
        struct sock             *sk;
        const struct proto_ops  *ops; /* Might change with IPV6_ADDRFORM or MPTCP. */

        struct socket_wq        wq;
};

/*
 * "descriptor" for what we're up to with a read.
 * This allows us to use the same read code yet
 * have multiple different users of the data that
 * we read from a file.
 *
 * The simplest case just copies the data to user
 * mode.
 */
typedef struct {
        size_t written;
        size_t count;
        union {
                char __user *buf;
                void *data;
        } arg;
        int error;
} read_descriptor_t;

struct vm_area_struct;
struct page;
struct msghdr;
struct module;
struct sk_buff;
struct proto_accept_arg;
typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *,
                               unsigned int, size_t);
typedef int (*skb_read_actor_t)(struct sock *, struct sk_buff *);


struct proto_ops {
        int             family;
        struct module   *owner;
        int             (*release)   (struct socket *sock);
        int             (*bind)      (struct socket *sock,
                                      struct sockaddr_unsized *myaddr,
                                      int sockaddr_len);
        int             (*connect)   (struct socket *sock,
                                      struct sockaddr_unsized *vaddr,
                                      int sockaddr_len, int flags);
        int             (*socketpair)(struct socket *sock1,
                                      struct socket *sock2);
        int             (*accept)    (struct socket *sock,
                                      struct socket *newsock,
                                      struct proto_accept_arg *arg);
        int             (*getname)   (struct socket *sock,
                                      struct sockaddr *addr,
                                      int peer);
        __poll_t        (*poll)      (struct file *file, struct socket *sock,
                                      struct poll_table_struct *wait);
        int             (*ioctl)     (struct socket *sock, unsigned int cmd,
                                      unsigned long arg);
#ifdef CONFIG_COMPAT
        int             (*compat_ioctl) (struct socket *sock, unsigned int cmd,
                                      unsigned long arg);
#endif
        int             (*gettstamp) (struct socket *sock, void __user *userstamp,
                                      bool timeval, bool time32);
        int             (*listen)    (struct socket *sock, int len);
        int             (*shutdown)  (struct socket *sock, int flags);
        int             (*setsockopt)(struct socket *sock, int level,
                                      int optname, sockptr_t optval,
                                      unsigned int optlen);
        int             (*getsockopt)(struct socket *sock, int level,
                                      int optname, char __user *optval, int __user *optlen);
        void            (*show_fdinfo)(struct seq_file *m, struct socket *sock);
        int             (*sendmsg)   (struct socket *sock, struct msghdr *m,
                                      size_t total_len);
        /* Notes for implementing recvmsg:
         * ===============================
         * msg->msg_namelen should get updated by the recvmsg handlers
         * iff msg_name != NULL. It is by default 0 to prevent
         * returning uninitialized memory to user space.  The recvfrom
         * handlers can assume that msg.msg_name is either NULL or has
         * a minimum size of sizeof(struct sockaddr_storage).
         */
        int             (*recvmsg)   (struct socket *sock, struct msghdr *m,
                                      size_t total_len, int flags);
        int             (*mmap)      (struct file *file, struct socket *sock,
                                      struct vm_area_struct * vma);
        ssize_t         (*splice_read)(struct socket *sock,  loff_t *ppos,
                                       struct pipe_inode_info *pipe, size_t len, unsigned int flags);
        void            (*splice_eof)(struct socket *sock);
        int             (*set_peek_off)(struct sock *sk, int val);
        int             (*peek_len)(struct socket *sock);

        /* The following functions are called internally by kernel with
         * sock lock already held.
         */
        int             (*read_sock)(struct sock *sk, read_descriptor_t *desc,
                                     sk_read_actor_t recv_actor);
        /* This is different from read_sock(), it reads an entire skb at a time. */
        int             (*read_skb)(struct sock *sk, skb_read_actor_t recv_actor);
        int             (*sendmsg_locked)(struct sock *sk, struct msghdr *msg,
                                          size_t size);
        int             (*set_rcvlowat)(struct sock *sk, int val);
};

#define DECLARE_SOCKADDR(type, dst, src)        \
        type dst = ({ __sockaddr_check_size(sizeof(*dst)); (type) src; })

struct net_proto_family {
        int             family;
        int             (*create)(struct net *net, struct socket *sock,
                                  int protocol, int kern);
        struct module   *owner;
};

struct iovec;
struct kvec;

enum {
        SOCK_WAKE_IO,
        SOCK_WAKE_WAITD,
        SOCK_WAKE_SPACE,
        SOCK_WAKE_URG,
};

int sock_wake_async(struct socket_wq *sk_wq, int how, int band);
int sock_register(const struct net_proto_family *fam);
void sock_unregister(int family);
bool sock_is_registered(int family);
int __sock_create(struct net *net, int family, int type, int proto,
                  struct socket **res, int kern);
int sock_create(int family, int type, int proto, struct socket **res);
int sock_create_kern(struct net *net, int family, int type, int proto, struct socket **res);
int sock_create_lite(int family, int type, int proto, struct socket **res);
struct socket *sock_alloc(void);
void sock_release(struct socket *sock);
int sock_sendmsg(struct socket *sock, struct msghdr *msg);
int sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags);
struct file *sock_alloc_file(struct socket *sock, int flags, const char *dname);
struct socket *sockfd_lookup(int fd, int *err);
struct socket *sock_from_file(struct file *file);
#define              sockfd_put(sock) fput(sock->file)
int net_ratelimit(void);

#define net_ratelimited_function(function, ...)                 \
do {                                                            \
        if (net_ratelimit())                                    \
                function(__VA_ARGS__);                          \
} while (0)

#define net_emerg_ratelimited(fmt, ...)                         \
        net_ratelimited_function(pr_emerg, fmt, ##__VA_ARGS__)
#define net_alert_ratelimited(fmt, ...)                         \
        net_ratelimited_function(pr_alert, fmt, ##__VA_ARGS__)
#define net_crit_ratelimited(fmt, ...)                          \
        net_ratelimited_function(pr_crit, fmt, ##__VA_ARGS__)
#define net_err_ratelimited(fmt, ...)                           \
        net_ratelimited_function(pr_err, fmt, ##__VA_ARGS__)
#define net_notice_ratelimited(fmt, ...)                        \
        net_ratelimited_function(pr_notice, fmt, ##__VA_ARGS__)
#define net_warn_ratelimited(fmt, ...)                          \
        net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
#define net_info_ratelimited(fmt, ...)                          \
        net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
#if defined(CONFIG_DYNAMIC_DEBUG) || \
        (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE))
#define net_dbg_ratelimited(fmt, ...)                                   \
do {                                                                    \
        DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt);                 \
        if (DYNAMIC_DEBUG_BRANCH(descriptor) &&                         \
            net_ratelimit())                                            \
                __dynamic_pr_debug(&descriptor, pr_fmt(fmt),            \
                                   ##__VA_ARGS__);                      \
} while (0)
#elif defined(DEBUG)
#define net_dbg_ratelimited(fmt, ...)                           \
        net_ratelimited_function(pr_debug, fmt, ##__VA_ARGS__)
#else
#define net_dbg_ratelimited(fmt, ...)                           \
        no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
#endif

#define net_get_random_once(buf, nbytes)                        \
        get_random_once((buf), (nbytes))

/*
 * E.g. XFS meta- & log-data is in slab pages, or bcache meta
 * data pages, or other high order pages allocated by
 * __get_free_pages() without __GFP_COMP, which have a page_count
 * of 0 and/or have PageSlab() set. We cannot use send_page for
 * those, as that does get_page(); put_page(); and would cause
 * either a VM_BUG directly, or __page_cache_release a page that
 * would actually still be referenced by someone, leading to some
 * obscure delayed Oops somewhere else.
 */
static inline bool sendpage_ok(struct page *page)
{
        return !PageSlab(page) && page_count(page) >= 1;
}

/*
 * Check sendpage_ok on contiguous pages.
 */
static inline bool sendpages_ok(struct page *page, size_t len, size_t offset)
{
        struct page *p = page + (offset >> PAGE_SHIFT);
        size_t count = 0;

        while (count < len) {
                if (!sendpage_ok(p))
                        return false;

                p++;
                count += PAGE_SIZE;
        }

        return true;
}

int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
                   size_t num, size_t len);
int kernel_recvmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
                   size_t num, size_t len, int flags);

int kernel_bind(struct socket *sock, struct sockaddr_unsized *addr, int addrlen);
int kernel_listen(struct socket *sock, int backlog);
int kernel_accept(struct socket *sock, struct socket **newsock, int flags);
int kernel_connect(struct socket *sock, struct sockaddr_unsized *addr, int addrlen,
                   int flags);
int kernel_getsockname(struct socket *sock, struct sockaddr *addr);
int kernel_getpeername(struct socket *sock, struct sockaddr *addr);
int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how);

/* Routine returns the IP overhead imposed by a (caller-protected) socket. */
u32 kernel_sock_ip_overhead(struct sock *sk);

#define MODULE_ALIAS_NETPROTO(proto) \
        MODULE_ALIAS("net-pf-" __stringify(proto))

#define MODULE_ALIAS_NET_PF_PROTO(pf, proto) \
        MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto))

#define MODULE_ALIAS_NET_PF_PROTO_TYPE(pf, proto, type) \
        MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \
                     "-type-" __stringify(type))

#define MODULE_ALIAS_NET_PF_PROTO_NAME(pf, proto, name) \
        MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \
                     name)
#endif  /* _LINUX_NET_H */