sockaddr_atop.c

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/*
** Copyright (C) 2005 by Kevin L. Mitchell <klmitch@mit.edu>
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**
** @(#)$Id: sockaddr_atop.c,v 1.6 2005/12/29 04:33:58 klmitch Exp $
*/
#include "event_int.h"

#include <stdio.h>
#include <string.h>

RCSTAG("@(#)$Id: sockaddr_atop.c,v 1.6 2005/12/29 04:33:58 klmitch Exp $");

static ev_err_t
atop_v4(const ev_sockaddr_t *sa, const unsigned char *addr, char *buf,
        ev_flags_t flags)
{
  ev_trace(); /* trace entry to function */

  buf += sprintf(buf, "%u.%u.%u.%u", addr[0], addr[1], addr[2], addr[3]);

  if (!(flags & SOCKADDR_ATOP_NOPORT)) /* format the port... */
    sprintf(buf, ".%u", sa_ipaddrport(sa));

  ev_return(0); /* trace exit from function */
}

static ev_err_t
atop_v6(const ev_sockaddr_t *sa, const unsigned char *addr, char *buf,
        ev_flags_t flags)
{
  uint16_t cooked[SOCK_ADDRBUFV6_LEN >> 1];
  struct {
    int start;
    int len;
  } best = { -1, -1 }, cur = { -1, -1 };
  int i;

  ev_trace(); /* trace entry to function */

  for (i = 0; i < (SOCK_ADDRBUFV6_LEN >> 1); i++) {
    /* Assemble 2 bytes into a single uint16_t */
    cooked[i] = (addr[i << 1] << 8) | addr[(i << 1) + 1];

    /* Now test if it's zero... */
    if (!cooked[i]) {
      /* Is it the start of a run? */
      if (cur.start < 0) {
        cur.start = i; /* remember the beginning point */
        cur.len = 1; /* and the length so far */
      } else
        cur.len++; /* increment the length */
    } else {
      if (cur.start >= 0 && (best.start < 0 || best.len < cur.len))
        best = cur; /* Found a better (read: longer) run */
      cur.start = -1; /* reset current run */
    }
  }

  /* Did we end on a run of 0s? */
  if (cur.start >= 0 && (best.start < 0 || best.len < cur.len))
    best = cur; /* Found a better 0 run */

  if (best.start >= 0 && best.len < 2) /* need at least 2 consecutive 0s */
    best.start = -1;

  /* OK, now do the formatting */
  for (i = 0; i < (SOCK_ADDRBUFV6_LEN >> 1); ) {
    if (i >= best.start && i < (best.start + best.len)) { /* in best run? */
      *buf++ = ':'; /* Add colon... */

      i = best.start + best.len; /* jump to next non-zero entry */

      if (i >= (SOCK_ADDRBUFV6_LEN >> 1)) {
        *buf++ = ':'; /* Add one more colon... */
        break; /* and bail out */
      }

      continue;
    }

    if (i)
      *buf++ = ':'; /* Add colon... */

    /* Is this an encapsulated v4 address? */
    if (i == 6 && best.start == 0 &&
        (best.len == 6 || (best.len == 5 && cooked[5] == 0xffff)))
      ev_return(atop_v4(sa, addr + (SOCK_ADDRBUFV6_LEN - SOCK_ADDRBUFV4_LEN),
                        buf, flags));

    /* OK, now fill in the address component */
    buf += sprintf(buf, "%x", cooked[i]);

    i++; /* move on... */
  }

  if (!(flags & SOCKADDR_ATOP_NOPORT)) /* format the port... */
    sprintf(buf, ".%u", sa_ipaddrport(sa));

  ev_return(0); /* trace exit from function */
}

ev_err_t
sockaddr_atop(const ev_sockaddr_t *sa, char *buf, int size, ev_flags_t flags)
{
  const char *src = 0;
  char addrbuf[SOCK_ADDRSTRV6_LEN + 6]; /* v6 address + ".65535" */

  ev_init(); /* make sure library is initialized... */

  /* sanity-check arguments */
  if (!sa || !buf || !size)
    ev_return(EINVAL);

  switch (sa->sa_type) {
  case AT_IPv6:
    src = addrbuf;
    atop_v6(sa, sa_ipaddrbuf(sa), addrbuf, flags); /* format v6 address */
    break;

  case AT_IPv4:
    src = addrbuf;
    atop_v4(sa, sa_ipaddrbuf(sa), addrbuf, flags); /* format v4 address */
    break;

  case AT_LOCAL: /* Local address; just the file name */
    src = sa_localaddr(sa);
    break;

  case AT_NONE: /* No address type... */
    src = "<NO ADDRESS>";
    break;
  }

  strncpy(buf, src, size); /* Copy the address into the user's buffer */
  buf[size - 1] = '\0'; /* make sure buffer gets terminated */

  ev_return(0);
}

---