/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006-2009 University of Zagreb
 * Copyright (c) 2006-2009 FreeBSD Foundation
 * All rights reserved.
 *
 * This software was developed by the University of Zagreb and the
 * FreeBSD Foundation under sponsorship by the Stichting NLnet and the
 * FreeBSD Foundation.
 *
 * Copyright (c) 2009 Jeffrey Roberson <jeff@freebsd.org>
 * Copyright (c) 2009 Robert N. M. Watson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*-
 * This header file defines several sets of interfaces supporting virtualized
 * network stacks:
 *
 * - Definition of 'struct vnet' and functions and macros to allocate/free/
 *   manipulate it.
 *
 * - A virtual network stack memory allocator, which provides support for
 *   virtualized global variables via a special linker set, set_vnet.
 *
 * - Virtualized sysinits/sysuninits, which allow constructors and
 *   destructors to be run for each network stack subsystem as virtual
 *   instances are created and destroyed.
 *
 * If VIMAGE isn't compiled into the kernel, virtualized global variables
 * compile to normal global variables, and virtualized sysinits to regular
 * sysinits.
 */

#ifndef _NET_VNET_H_
#define _NET_VNET_H_

/*
 * struct vnet describes a virtualized network stack, and is primarily a
 * pointer to storage for virtualized global variables.  Expose to userspace
 * as required for libkvm.
 */
#if defined(_KERNEL) || defined(_WANT_VNET)
#include <machine/param.h>      /* for CACHE_LINE_SIZE */
#include <sys/queue.h>

struct vnet {
        LIST_ENTRY(vnet)         vnet_le;       /* all vnets list */
        u_int                    vnet_magic_n;
        u_int                    vnet_ifcnt;
        u_int                    vnet_sockcnt;
        u_int                    vnet_state;    /* SI_SUB_* */
        void                    *vnet_data_mem;
        uintptr_t                vnet_data_base;
        bool                     vnet_shutdown; /* Shutdown in progress. */
} __aligned(CACHE_LINE_SIZE);
#define VNET_MAGIC_N    0x5e4a6f28

/*
 * These two virtual network stack allocator definitions are also required
 * for libkvm so that it can evaluate virtualized global variables.
 */
#define VNET_SETNAME            "set_vnet"
#define VNET_SYMPREFIX          "vnet_entry_"
#endif

#ifdef _KERNEL

#define VNET_PCPUSTAT_DECLARE(type, name)       \
    VNET_DECLARE(counter_u64_t, name[sizeof(type) / sizeof(uint64_t)])

#define VNET_PCPUSTAT_DEFINE(type, name)        \
    VNET_DEFINE(counter_u64_t, name[sizeof(type) / sizeof(uint64_t)])
#define VNET_PCPUSTAT_DEFINE_STATIC(type, name) \
    VNET_DEFINE_STATIC(counter_u64_t, name[sizeof(type) / sizeof(uint64_t)])

#define VNET_PCPUSTAT_ALLOC(name, wait) \
    COUNTER_ARRAY_ALLOC(VNET(name), \
        sizeof(VNET(name)) / sizeof(counter_u64_t), (wait))

#define VNET_PCPUSTAT_FREE(name)        \
    COUNTER_ARRAY_FREE(VNET(name), sizeof(VNET(name)) / sizeof(counter_u64_t))

#define VNET_PCPUSTAT_ADD(type, name, f, v)     \
    counter_u64_add(VNET(name)[offsetof(type, f) / sizeof(uint64_t)], (v))

#define VNET_PCPUSTAT_FETCH(type, name, f)      \
    counter_u64_fetch(VNET(name)[offsetof(type, f) / sizeof(uint64_t)])

#define VNET_PCPUSTAT_SYSINIT(name)     \
static void                             \
vnet_##name##_init(const void *unused)  \
{                                       \
        VNET_PCPUSTAT_ALLOC(name, M_WAITOK);    \
}                                       \
VNET_SYSINIT(vnet_ ## name ## _init, SI_SUB_INIT_IF,                    \
    SI_ORDER_FIRST, vnet_ ## name ## _init, NULL)

#define VNET_PCPUSTAT_SYSUNINIT(name)                                   \
static void                                                             \
vnet_##name##_uninit(const void *unused)                                \
{                                                                       \
        VNET_PCPUSTAT_FREE(name);                                       \
}                                                                       \
VNET_SYSUNINIT(vnet_ ## name ## _uninit, SI_SUB_INIT_IF,                \
    SI_ORDER_FIRST, vnet_ ## name ## _uninit, NULL)

#ifdef SYSCTL_OID
#define SYSCTL_VNET_PCPUSTAT(parent, nbr, name, type, array, desc)      \
static int                                                              \
array##_sysctl(SYSCTL_HANDLER_ARGS)                                     \
{                                                                       \
        type s;                                                         \
        CTASSERT((sizeof(type) / sizeof(uint64_t)) ==                   \
            (sizeof(VNET(array)) / sizeof(counter_u64_t)));             \
        COUNTER_ARRAY_COPY(VNET(array), &s, sizeof(type) / sizeof(uint64_t));\
        if (req->newptr)                                                \
                COUNTER_ARRAY_ZERO(VNET(array),                         \
                    sizeof(type) / sizeof(uint64_t));                   \
        return (SYSCTL_OUT(req, &s, sizeof(type)));                     \
}                                                                       \
SYSCTL_PROC(parent, nbr, name,                                          \
    CTLFLAG_VNET | CTLTYPE_OPAQUE | CTLFLAG_RW | CTLFLAG_NEEDGIANT,     \
    NULL, 0, array ## _sysctl, "I", desc)
#endif /* SYSCTL_OID */

#ifdef VIMAGE
#include <sys/lock.h>
#include <sys/proc.h>                   /* for struct thread */
#include <sys/rwlock.h>
#include <sys/sx.h>

/*
 * Location of the kernel's 'set_vnet' linker set.
 */
extern uintptr_t        *__start_set_vnet;
__GLOBL(__start_set_vnet);
extern uintptr_t        *__stop_set_vnet;
__GLOBL(__stop_set_vnet);

#define VNET_START      (uintptr_t)&__start_set_vnet
#define VNET_STOP       (uintptr_t)&__stop_set_vnet

/*
 * Functions to allocate and destroy virtual network stacks.
 */
struct vnet *vnet_alloc(void);
void    vnet_destroy(struct vnet *vnet);

/*
 * The current virtual network stack -- we may wish to move this to struct
 * pcpu in the future.
 */
#define curvnet curthread->td_vnet

/*
 * Various macros -- get and set the current network stack, but also
 * assertions.
 */
#if defined(INVARIANTS) || defined(VNET_DEBUG)
#define VNET_ASSERT(exp, msg)   do {                                    \
        if (!(exp))                                                     \
                panic msg;                                              \
} while (0)
#else
#define VNET_ASSERT(exp, msg)   do {                                    \
} while (0)
#endif

#ifdef VNET_DEBUG
void vnet_log_recursion(struct vnet *, const char *, int);

#define CURVNET_SET_QUIET(arg)                                          \
        VNET_ASSERT((arg) != NULL && (arg)->vnet_magic_n == VNET_MAGIC_N, \
            ("CURVNET_SET at %s:%d %s() curvnet=%p vnet=%p",            \
            __FILE__, __LINE__, __func__, curvnet, (arg)));             \
        struct vnet *saved_vnet = curvnet;                              \
        const char *saved_vnet_lpush = curthread->td_vnet_lpush;        \
        curvnet = arg;                                                  \
        curthread->td_vnet_lpush = __func__;

#define CURVNET_SET_VERBOSE(arg)                                        \
        CURVNET_SET_QUIET(arg)                                          \
        if (saved_vnet)                                                 \
                vnet_log_recursion(saved_vnet, saved_vnet_lpush, __LINE__);

#define CURVNET_SET(arg)        CURVNET_SET_VERBOSE(arg)

#define CURVNET_RESTORE()                                               \
        VNET_ASSERT(curvnet != NULL && (saved_vnet == NULL ||           \
            saved_vnet->vnet_magic_n == VNET_MAGIC_N),                  \
            ("CURVNET_RESTORE at %s:%d %s() curvnet=%p saved_vnet=%p",  \
            __FILE__, __LINE__, __func__, curvnet, saved_vnet));        \
        curvnet = saved_vnet;                                           \
        curthread->td_vnet_lpush = saved_vnet_lpush;
#else /* !VNET_DEBUG */

#define CURVNET_SET_QUIET(arg)                                          \
        VNET_ASSERT((arg) != NULL && (arg)->vnet_magic_n == VNET_MAGIC_N, \
            ("CURVNET_SET at %s:%d %s() curvnet=%p vnet=%p",            \
            __FILE__, __LINE__, __func__, curvnet, (arg)));             \
        struct vnet *saved_vnet = curvnet;                              \
        curvnet = arg;  

#define CURVNET_SET_VERBOSE(arg)                                        \
        CURVNET_SET_QUIET(arg)

#define CURVNET_SET(arg)        CURVNET_SET_VERBOSE(arg)

#define CURVNET_RESTORE()                                               \
        VNET_ASSERT(curvnet != NULL && (saved_vnet == NULL ||           \
            saved_vnet->vnet_magic_n == VNET_MAGIC_N),                  \
            ("CURVNET_RESTORE at %s:%d %s() curvnet=%p saved_vnet=%p",  \
            __FILE__, __LINE__, __func__, curvnet, saved_vnet));        \
        curvnet = saved_vnet;
#endif /* VNET_DEBUG */

#define CURVNET_ASSERT_SET()                                            \
        VNET_ASSERT(curvnet != NULL, ("vnet is not set at %s:%d %s()",  \
            __FILE__, __LINE__, __func__))

extern struct vnet *vnet0;
#define IS_DEFAULT_VNET(arg)    ((arg) == vnet0)

#define CRED_TO_VNET(cr)        (cr)->cr_prison->pr_vnet
#define TD_TO_VNET(td)          CRED_TO_VNET((td)->td_ucred)
#define P_TO_VNET(p)            CRED_TO_VNET((p)->p_ucred)

/*
 * Global linked list of all virtual network stacks, along with read locks to
 * access it.  If a caller may sleep while accessing the list, it must use
 * the sleepable lock macros.
 */
LIST_HEAD(vnet_list_head, vnet);
extern struct vnet_list_head vnet_head;
extern struct rwlock vnet_rwlock;
extern struct sx vnet_sxlock;

#define VNET_LIST_RLOCK()               sx_slock(&vnet_sxlock)
#define VNET_LIST_RLOCK_NOSLEEP()       rw_rlock(&vnet_rwlock)
#define VNET_LIST_RUNLOCK()             sx_sunlock(&vnet_sxlock)
#define VNET_LIST_RUNLOCK_NOSLEEP()     rw_runlock(&vnet_rwlock)

/*
 * Iteration macros to walk the global list of virtual network stacks.
 */
#define VNET_ITERATOR_DECL(arg) struct vnet *arg
#define VNET_FOREACH(arg)       LIST_FOREACH((arg), &vnet_head, vnet_le)

/*
 * Virtual network stack memory allocator, which allows global variables to
 * be automatically instantiated for each network stack instance.
 */
#define VNET_NAME(n)            vnet_entry_##n
#define VNET_DECLARE(t, n)      extern t VNET_NAME(n)
/* struct _hack is to stop this from being used with static data */
#define VNET_DEFINE(t, n)       \
    struct _hack; t VNET_NAME(n) __section(VNET_SETNAME) __used
#if defined(KLD_MODULE) && (defined(__aarch64__) || defined(__riscv) \
                || defined(__powerpc64__) || defined(__i386__))
/*
 * As with DPCPU_DEFINE_STATIC we are unable to mark this data as static
 * in modules on some architectures.
 */
#define VNET_DEFINE_STATIC(t, n) \
    t VNET_NAME(n) __section(VNET_SETNAME) __used
#else
#define VNET_DEFINE_STATIC(t, n) \
    static t VNET_NAME(n) __section(VNET_SETNAME) __used
#endif
#define _VNET_PTR(b, n)         (__typeof(VNET_NAME(n))*)               \
                                    ((b) + (uintptr_t)&VNET_NAME(n))

#define _VNET(b, n)             (*_VNET_PTR(b, n))

/*
 * Virtualized global variable accessor macros.
 */
#define VNET_VNET_PTR(vnet, n)          _VNET_PTR((vnet)->vnet_data_base, n)
#define VNET_VNET(vnet, n)              (*VNET_VNET_PTR((vnet), n))

#define VNET_PTR(n)             VNET_VNET_PTR(curvnet, n)
#define VNET(n)                 VNET_VNET(curvnet, n)

/*
 * Virtual network stack allocator interfaces from the kernel linker.
 */
void    *vnet_data_alloc(int size);
void     vnet_data_copy(void *start, int size);
void     vnet_data_free(void *start_arg, int size);

/*
 * Interfaces to manipulate the initial values of virtualized global variables.
 */
void    vnet_save_init(void *, size_t);
void    vnet_restore_init(void *, size_t);

/*
 * Virtual sysinit mechanism, allowing network stack components to declare
 * startup and shutdown methods to be run when virtual network stack
 * instances are created and destroyed.
 */
#include <sys/kernel.h>

/*
 * SYSINIT/SYSUNINIT variants that provide per-vnet constructors and
 * destructors.
 */
struct vnet_sysinit {
        enum sysinit_sub_id     subsystem;
        enum sysinit_elem_order order;
        sysinit_cfunc_t         func;
        const void              *arg;
        TAILQ_ENTRY(vnet_sysinit) link;
};

#define VNET_SYSINIT(ident, subsystem, order, func, arg)                \
        CTASSERT((subsystem) > SI_SUB_VNET &&                           \
            (subsystem) <= SI_SUB_VNET_DONE);                           \
        static struct vnet_sysinit ident ## _vnet_init = {              \
                subsystem,                                              \
                order,                                                  \
                (sysinit_cfunc_t)(sysinit_nfunc_t)func,                 \
                (arg)                                                   \
        };                                                              \
        SYSINIT(vnet_init_ ## ident, subsystem, order,                  \
            vnet_register_sysinit, &ident ## _vnet_init);               \
        SYSUNINIT(vnet_init_ ## ident, subsystem, order,                \
            vnet_deregister_sysinit, &ident ## _vnet_init)

#define VNET_SYSUNINIT(ident, subsystem, order, func, arg)              \
        CTASSERT((subsystem) > SI_SUB_VNET &&                           \
            (subsystem) <= SI_SUB_VNET_DONE);                           \
        static struct vnet_sysinit ident ## _vnet_uninit = {            \
                subsystem,                                              \
                order,                                                  \
                (sysinit_cfunc_t)(sysinit_nfunc_t)func,                 \
                (arg)                                                   \
        };                                                              \
        SYSINIT(vnet_uninit_ ## ident, subsystem, order,                \
            vnet_register_sysuninit, &ident ## _vnet_uninit);           \
        SYSUNINIT(vnet_uninit_ ## ident, subsystem, order,              \
            vnet_deregister_sysuninit, &ident ## _vnet_uninit)

/*
 * Interfaces for managing per-vnet constructors and destructors.
 */
void    vnet_register_sysinit(void *arg);
void    vnet_register_sysuninit(void *arg);
void    vnet_deregister_sysinit(void *arg);
void    vnet_deregister_sysuninit(void *arg);

/*
 * EVENTHANDLER(9) extensions.
 */
#include <sys/eventhandler.h>

void    vnet_global_eventhandler_iterator_func(void *, ...);
#define VNET_GLOBAL_EVENTHANDLER_REGISTER_TAG(tag, name, func, arg, priority) \
do {                                                                    \
        if (IS_DEFAULT_VNET(curvnet)) {                                 \
                (tag) = vimage_eventhandler_register(NULL, #name, func, \
                    arg, priority,                                      \
                    vnet_global_eventhandler_iterator_func);            \
        }                                                               \
} while(0)
#define VNET_GLOBAL_EVENTHANDLER_REGISTER(name, func, arg, priority)    \
do {                                                                    \
        if (IS_DEFAULT_VNET(curvnet)) {                                 \
                vimage_eventhandler_register(NULL, #name, func,         \
                    arg, priority,                                      \
                    vnet_global_eventhandler_iterator_func);            \
        }                                                               \
} while(0)

#define VNET_IS_SHUTTING_DOWN(_vnet)    \
            ((_vnet)->vnet_shutdown && (_vnet)->vnet_state < SI_SUB_VNET_DONE)

#else /* !VIMAGE */

/*
 * Various virtual network stack macros compile to no-ops without VIMAGE.
 */
#define curvnet                 NULL

#define VNET_ASSERT(exp, msg)
#define CURVNET_SET(arg)
#define CURVNET_SET_QUIET(arg)
#define CURVNET_RESTORE()
#define CURVNET_ASSERT_SET()

#define VNET_LIST_RLOCK()
#define VNET_LIST_RLOCK_NOSLEEP()
#define VNET_LIST_RUNLOCK()
#define VNET_LIST_RUNLOCK_NOSLEEP()
#define VNET_ITERATOR_DECL(arg)
#define VNET_FOREACH(arg)       for (int _vn = 0; _vn == 0; _vn++)

#define IS_DEFAULT_VNET(arg)    1
#define CRED_TO_VNET(cr)        NULL
#define TD_TO_VNET(td)          NULL
#define P_TO_VNET(p)            NULL

/*
 * Versions of the VNET macros that compile to normal global variables and
 * standard sysctl definitions.
 */
#define VNET_NAME(n)            n
#define VNET_DECLARE(t, n)      extern t n
#define VNET_DEFINE(t, n)       struct _hack; t n
#define VNET_DEFINE_STATIC(t, n)        static t n
#define _VNET_PTR(b, n)         &VNET_NAME(n)

/*
 * Virtualized global variable accessor macros.
 */
#define VNET_VNET_PTR(vnet, n)          (&(n))
#define VNET_VNET(vnet, n)              (n)

#define VNET_PTR(n)             (&(n))
#define VNET(n)                 (n)

/*
 * When VIMAGE isn't compiled into the kernel, VNET_SYSINIT/VNET_SYSUNINIT
 * map into normal sysinits, which have the same ordering properties.
 */
#define VNET_SYSINIT(ident, subsystem, order, func, arg)                \
        SYSINIT(ident, subsystem, order, func, arg)
#define VNET_SYSUNINIT(ident, subsystem, order, func, arg)              \
        SYSUNINIT(ident, subsystem, order, func, arg)

/*
 * Without VIMAGE revert to the default implementation.
 */
#define VNET_GLOBAL_EVENTHANDLER_REGISTER_TAG(tag, name, func, arg, priority) \
        (tag) = eventhandler_register(NULL, #name, func, arg, priority)
#define VNET_GLOBAL_EVENTHANDLER_REGISTER(name, func, arg, priority)    \
        eventhandler_register(NULL, #name, func, arg, priority)
#endif /* VIMAGE */
#endif /* _KERNEL */

#endif /* !_NET_VNET_H_ */