/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
 *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
 *                           Internet Initiative Japan, Inc (IIJ)
 * 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.
 */

#include <sys/types.h>

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <termios.h>

#include "defs.h"
#include "command.h"
#include "mbuf.h"
#include "log.h"
#include "descriptor.h"
#include "prompt.h"
#include "main.h"

#define BUCKET_CHUNK    20
#define BUCKET_HASH     256

struct mbucket;

struct mfree {
  struct mbucket *next;
  size_t count;
};

static struct mbucket {
  union {
    struct mbuf m;
    struct mfree f;
  } u;
} *bucket[(M_MAXLEN + sizeof(struct mbuf)) / BUCKET_HASH];

#define M_BINDEX(sz)    (((sz) + sizeof(struct mbuf) - 1) / BUCKET_HASH)
#define M_BUCKET(sz)    (bucket + M_BINDEX(sz))
#define M_ROUNDUP(sz)   ((M_BINDEX(sz) + 1) * BUCKET_HASH)

static struct memmap {
  struct mbuf *queue;
  size_t fragments;
  size_t octets;
} MemMap[MB_MAX + 1];

static unsigned long long mbuf_Mallocs, mbuf_Frees;

size_t
m_length(struct mbuf *bp)
{
  size_t len;

  for (len = 0; bp; bp = bp->m_next)
    len += bp->m_len;
  return len;
}

static const char *
mbuftype(int type)
{
  static const char * const mbufdesc[MB_MAX] = {
    "ip in", "ip out", "ipv6 in", "ipv6 out", "nat in", "nat out",
    "mp in", "mp out", "vj in", "vj out", "icompd in", "icompd out",
    "compd in", "compd out", "lqr in", "lqr out", "echo in", "echo out",
    "proto in", "proto out", "acf in", "acf out", "sync in", "sync out",
    "hdlc in", "hdlc out", "async in", "async out", "cbcp in", "cbcp out",
    "chap in", "chap out", "pap in", "pap out", "ccp in", "ccp out",
    "ipcp in", "ipcp out", "ipv6cp in", "ipv6cp out", "lcp in", "lcp out"
  };

  return type < 0 || type >= MB_MAX ? "unknown" : mbufdesc[type];
}

struct mbuf *
m_get(size_t m_len, int type)
{
  struct mbucket **mb;
  struct mbuf *bp;
  size_t size;

  if (type > MB_MAX) {
    log_Printf(LogERROR, "Bad mbuf type %d\n", type);
    type = MB_UNKNOWN;
  }

  if (m_len > M_MAXLEN || m_len == 0) {
    log_Printf(LogERROR, "Request for mbuf size %lu (\"%s\") denied !\n",
               (u_long)m_len, mbuftype(type));
    AbortProgram(EX_OSERR);
  }

  mb = M_BUCKET(m_len);
  size = M_ROUNDUP(m_len);

  if (*mb) {
    /* We've got some free blocks of the right size */
    bp = &(*mb)->u.m;
    if (--(*mb)->u.f.count == 0)
      *mb = (*mb)->u.f.next;
    else {
      ((struct mbucket *)((char *)*mb + size))->u.f.count = (*mb)->u.f.count;
      *mb = (struct mbucket *)((char *)*mb + size);
      (*mb)->u.f.next = NULL;
    }
  } else {
    /*
     * Allocate another chunk of mbufs, use the first and put the rest on
     * the free list
     */
    *mb = (struct mbucket *)malloc(BUCKET_CHUNK * size);
    if (*mb == NULL) {
      log_Printf(LogALERT, "Failed to allocate memory (%lu)\n",
                 (unsigned long)BUCKET_CHUNK * size);
      AbortProgram(EX_OSERR);
    }
    bp = &(*mb)->u.m;
    *mb = (struct mbucket *)((char *)*mb + size);
    (*mb)->u.f.count = BUCKET_CHUNK - 1;
    (*mb)->u.f.next = NULL;
  }

  mbuf_Mallocs++;

  memset(bp, '\0', sizeof(struct mbuf));
  bp->m_size = size - sizeof *bp;
  bp->m_len = m_len;
  bp->m_type = type;

  MemMap[type].fragments++;
  MemMap[type].octets += bp->m_size;

  return bp;
}

struct mbuf *
m_free(struct mbuf *bp)
{
  struct mbucket **mb, *f;
  struct mbuf *nbp;

  if ((f = (struct mbucket *)bp) != NULL) {
    MemMap[bp->m_type].fragments--;
    MemMap[bp->m_type].octets -= bp->m_size;

    nbp = bp->m_next;
    mb = M_BUCKET(bp->m_size);
    f->u.f.next = *mb;
    f->u.f.count = 1;
    *mb = f;

    mbuf_Frees++;
    bp = nbp;
  }

  return bp;
}

void
m_freem(struct mbuf *bp)
{
  while (bp)
    bp = m_free(bp);
}

struct mbuf *
mbuf_Read(struct mbuf *bp, void *v, size_t len)
{
  int nb;
  u_char *ptr = v;

  while (bp && len > 0) {
    if (len > bp->m_len)
      nb = bp->m_len;
    else
      nb = len;
    if (nb) {
      memcpy(ptr, MBUF_CTOP(bp), nb);
      ptr += nb;
      bp->m_len -= nb;
      len -= nb;
      bp->m_offset += nb;
    }
    if (bp->m_len == 0)
      bp = m_free(bp);
  }

  while (bp && bp->m_len == 0)
    bp = m_free(bp);

  return bp;
}

size_t
mbuf_View(struct mbuf *bp, void *v, size_t len)
{
  size_t nb, l = len;
  u_char *ptr = v;

  while (bp && l > 0) {
    if (l > bp->m_len)
      nb = bp->m_len;
    else
      nb = l;
    memcpy(ptr, MBUF_CTOP(bp), nb);
    ptr += nb;
    l -= nb;
    bp = bp->m_next;
  }

  return len - l;
}

struct mbuf *
m_prepend(struct mbuf *bp, const void *ptr, size_t len, u_short extra)
{
  struct mbuf *head;

  if (bp && bp->m_offset) {
    if (bp->m_offset >= len) {
      bp->m_offset -= len;
      bp->m_len += len;
      if (ptr)
        memcpy(MBUF_CTOP(bp), ptr, len);
      return bp;
    }
    len -= bp->m_offset;
    if (ptr)
      memcpy(bp + 1, (const char *)ptr + len, bp->m_offset);
    bp->m_len += bp->m_offset;
    bp->m_offset = 0;
  }

  head = m_get(len + extra, bp ? bp->m_type : MB_UNKNOWN);
  head->m_offset = extra;
  head->m_len -= extra;
  if (ptr)
    memcpy(MBUF_CTOP(head), ptr, len);
  head->m_next = bp;

  return head;
}

struct mbuf *
m_adj(struct mbuf *bp, ssize_t n)
{
  if (n > 0) {
    while (bp) {
      if ((size_t)n < bp->m_len) {
        bp->m_len = n;
        bp->m_offset += n;
        return bp;
      }
      n -= bp->m_len;
      bp = m_free(bp);
    }
  } else {
    if ((n = m_length(bp) + n) <= 0) {
      m_freem(bp);
      return NULL;
    }
    for (; bp; bp = bp->m_next, n -= bp->m_len)
      if ((size_t)n < bp->m_len) {
        bp->m_len = n;
        m_freem(bp->m_next);
        bp->m_next = NULL;
        break;
      }
  }

  return bp;
}

void
mbuf_Write(struct mbuf *bp, const void *ptr, size_t m_len)
{
  size_t plen;
  int nb;

  plen = m_length(bp);
  if (plen < m_len)
    m_len = plen;

  while (m_len > 0) {
    nb = (m_len < bp->m_len) ? m_len : bp->m_len;
    memcpy(MBUF_CTOP(bp), ptr, nb);
    m_len -= bp->m_len;
    bp = bp->m_next;
  }
}

int
mbuf_Show(struct cmdargs const *arg)
{
  int i;

  prompt_Printf(arg->prompt, "Fragments (octets) in use:\n");
  for (i = 0; i < MB_MAX; i += 2)
    prompt_Printf(arg->prompt, "%10.10s: %04lu (%06lu)\t"
                  "%10.10s: %04lu (%06lu)\n",
                  mbuftype(i), (u_long)MemMap[i].fragments,
                  (u_long)MemMap[i].octets, mbuftype(i+1),
                  (u_long)MemMap[i+1].fragments, (u_long)MemMap[i+1].octets);

  if (i == MB_MAX)
    prompt_Printf(arg->prompt, "%10.10s: %04lu (%06lu)\n",
                  mbuftype(i), (u_long)MemMap[i].fragments,
                  (u_long)MemMap[i].octets);

  prompt_Printf(arg->prompt, "Mallocs: %llu,   Frees: %llu\n",
                mbuf_Mallocs, mbuf_Frees);

  return 0;
}

struct mbuf *
m_dequeue(struct mqueue *q)
{
  struct mbuf *bp;

  log_Printf(LogDEBUG, "m_dequeue: queue len = %lu\n", (u_long)q->len);
  bp = q->top;
  if (bp) {
    q->top = q->top->m_nextpkt;
    q->len--;
    if (q->top == NULL) {
      q->last = q->top;
      if (q->len)
        log_Printf(LogERROR, "m_dequeue: Not zero (%lu)!!!\n",
                   (u_long)q->len);
    }
    bp->m_nextpkt = NULL;
  }

  return bp;
}

void
m_enqueue(struct mqueue *queue, struct mbuf *bp)
{
  if (bp != NULL) {
    if (queue->last) {
      queue->last->m_nextpkt = bp;
      queue->last = bp;
    } else
      queue->last = queue->top = bp;
    queue->len++;
    log_Printf(LogDEBUG, "m_enqueue: len = %lu\n", (unsigned long)queue->len);
  }
}

struct mbuf *
m_pullup(struct mbuf *bp)
{
  /* Put it all in one contigous (aligned) mbuf */

  if (bp != NULL) {
    if (bp->m_next != NULL) {
      struct mbuf *nbp;
      u_char *cp;

      nbp = m_get(m_length(bp), bp->m_type);

      for (cp = MBUF_CTOP(nbp); bp; bp = m_free(bp)) {
        memcpy(cp, MBUF_CTOP(bp), bp->m_len);
        cp += bp->m_len;
      }
      bp = nbp;
    }
#ifndef __i386__        /* Do any other archs not care about alignment ? */
    else if ((bp->m_offset & (sizeof(long) - 1)) != 0) {
      bcopy(MBUF_CTOP(bp), bp + 1, bp->m_len);
      bp->m_offset = 0;
    }
#endif
  }

  return bp;
}

void
m_settype(struct mbuf *bp, int type)
{
  for (; bp; bp = bp->m_next)
    if (type != bp->m_type) {
      MemMap[bp->m_type].fragments--;
      MemMap[bp->m_type].octets -= bp->m_size;
      bp->m_type = type;
      MemMap[type].fragments++;
      MemMap[type].octets += bp->m_size;
    }
}

struct mbuf *
m_append(struct mbuf *bp, const void *v, size_t sz)
{
  struct mbuf *m = bp;

  if (m) {
    while (m->m_next)
      m = m->m_next;
    if (m->m_size - m->m_len >= sz) {
      if (v)
        memcpy((char *)(m + 1) + m->m_len, v, sz);
      m->m_len += sz;
    } else
      m->m_next = m_prepend(NULL, v, sz, 0);
  } else
    bp = m_prepend(NULL, v, sz, 0);

  return bp;
}