dnscrypto-proxy: Update to release 1.3.0

[tomato.git] / release / src / router / dnscrypt / src / libevent-modified / event_tagging.c

/*
 * Copyright (c) 2003-2009 Niels Provos <provos@citi.umich.edu>
 * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 "event2/event-config.h"

#ifdef _EVENT_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef _EVENT_HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef WIN32
#define WIN32_LEAN_AND_MEAN
#include <winsock2.h>
#include <windows.h>
#undef WIN32_LEAN_AND_MEAN
#else
#include <sys/ioctl.h>
#endif

#include <sys/queue.h>
#ifdef _EVENT_HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifndef WIN32
#include <syslog.h>
#endif
#ifdef _EVENT_HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <limits.h>

#include "event2/event.h"
#include "event2/tag.h"
#include "event2/buffer.h"
#include "log-internal.h"
#include "mm-internal.h"
#include "util-internal.h"

/*
  Here's our wire format:

  Stream = TaggedData*

  TaggedData = Tag Length Data
       where the integer value of 'Length' is the length of 'data'.

  Tag = HByte* LByte
       where HByte is a byte with the high bit set, and LByte is a byte
       with the high bit clear. The integer value of the tag is taken
       by concatenating the lower 7 bits from all the tags.  So for example,
       the tag 0x66 is encoded as [66], whereas the tag 0x166 is encoded as
       [82 66]

  Length = Integer

  Integer = NNibbles Nibble* Padding?
       where NNibbles is a 4-bit value encoding the number of nibbles-1,
       and each Nibble is 4 bits worth of encoded integer, in big-endian
       order.  If the total encoded integer size is an odd number of nibbles,
       a final padding nibble with value 0 is appended.
*/

int evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf);
int evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf);
int evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag);
int evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf);

void
evtag_init(void)
{
}

/*
 * We encode integers by nibbles; the first nibble contains the number
 * of significant nibbles - 1;  this allows us to encode up to 64-bit
 * integers.  This function is byte-order independent.
 *
 * @param number a 32-bit unsigned integer to encode
 * @param data a pointer to where the data should be written.  Must
 *    have at least 5 bytes free.
 * @return the number of bytes written into data.
 */

#define ENCODE_INT_INTERNAL(data, number) do {                          \
        int off = 1, nibbles = 0;                                       \
                                                                        \
        memset(data, 0, sizeof(number)+1);                              \
        while (number) {                                                \
                if (off & 0x1)                                          \
                        data[off/2] = (data[off/2] & 0xf0) | (number & 0x0f); \
                else                                                    \
                        data[off/2] = (data[off/2] & 0x0f) |            \
                            ((number & 0x0f) << 4);                     \
                number >>= 4;                                           \
                off++;                                                  \
        }                                                               \
                                                                        \
        if (off > 2)                                                    \
                nibbles = off - 2;                                      \
                                                                        \
        /* Off - 1 is the number of encoded nibbles */                  \
        data[0] = (data[0] & 0x0f) | ((nibbles & 0x0f) << 4);           \
                                                                        \
        return ((off + 1) / 2);                                         \
} while (0)

static inline int
encode_int_internal(ev_uint8_t *data, ev_uint32_t number)
{
        ENCODE_INT_INTERNAL(data, number);
}

static inline int
encode_int64_internal(ev_uint8_t *data, ev_uint64_t number)
{
        ENCODE_INT_INTERNAL(data, number);
}

void
evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number)
{
        ev_uint8_t data[5];
        int len = encode_int_internal(data, number);
        evbuffer_add(evbuf, data, len);
}

void
evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number)
{
        ev_uint8_t data[9];
        int len = encode_int64_internal(data, number);
        evbuffer_add(evbuf, data, len);
}

/*
 * Support variable length encoding of tags; we use the high bit in each
 * octet as a continuation signal.
 */

int
evtag_encode_tag(struct evbuffer *evbuf, ev_uint32_t tag)
{
        int bytes = 0;
        ev_uint8_t data[5];

        memset(data, 0, sizeof(data));
        do {
                ev_uint8_t lower = tag & 0x7f;
                tag >>= 7;

                if (tag)
                        lower |= 0x80;

                data[bytes++] = lower;
        } while (tag);

        if (evbuf != NULL)
                evbuffer_add(evbuf, data, bytes);

        return (bytes);
}

static int
decode_tag_internal(ev_uint32_t *ptag, struct evbuffer *evbuf, int dodrain)
{
        ev_uint32_t number = 0;
        size_t len = evbuffer_get_length(evbuf);
        ev_uint8_t *data;
        size_t count = 0;
        int  shift = 0, done = 0;

        /*
         * the encoding of a number is at most one byte more than its
         * storage size.  however, it may also be much smaller.
         */
        data = evbuffer_pullup(
                evbuf, len < sizeof(number) + 1 ? len : sizeof(number) + 1);

        while (count++ < len) {
                ev_uint8_t lower = *data++;
                number |= (lower & 0x7f) << shift;
                shift += 7;

                if (!(lower & 0x80)) {
                        done = 1;
                        break;
                }
        }

        if (!done)
                return (-1);

        if (dodrain)
                evbuffer_drain(evbuf, count);

        if (ptag != NULL)
                *ptag = number;

        return count > INT_MAX ? INT_MAX : (int)(count);
}

int
evtag_decode_tag(ev_uint32_t *ptag, struct evbuffer *evbuf)
{
        return (decode_tag_internal(ptag, evbuf, 1 /* dodrain */));
}

/*
 * Marshal a data type, the general format is as follows:
 *
 * tag number: one byte; length: var bytes; payload: var bytes
 */

void
evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag,
    const void *data, ev_uint32_t len)
{
        evtag_encode_tag(evbuf, tag);
        evtag_encode_int(evbuf, len);
        evbuffer_add(evbuf, (void *)data, len);
}

void
evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag,
    struct evbuffer *data)
{
        evtag_encode_tag(evbuf, tag);
        /* XXX support more than UINT32_MAX data */
        evtag_encode_int(evbuf, (ev_uint32_t)evbuffer_get_length(data));
        evbuffer_add_buffer(evbuf, data);
}

/* Marshaling for integers */
void
evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag, ev_uint32_t integer)
{
        ev_uint8_t data[5];
        int len = encode_int_internal(data, integer);

        evtag_encode_tag(evbuf, tag);
        evtag_encode_int(evbuf, len);
        evbuffer_add(evbuf, data, len);
}

void
evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag,
    ev_uint64_t integer)
{
        ev_uint8_t data[9];
        int len = encode_int64_internal(data, integer);

        evtag_encode_tag(evbuf, tag);
        evtag_encode_int(evbuf, len);
        evbuffer_add(evbuf, data, len);
}

void
evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag, const char *string)
{
        /* TODO support strings longer than UINT32_MAX ? */
        evtag_marshal(buf, tag, string, (ev_uint32_t)strlen(string));
}

void
evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag, struct timeval *tv)
{
        ev_uint8_t data[10];
        int len = encode_int_internal(data, tv->tv_sec);
        len += encode_int_internal(data + len, tv->tv_usec);
        evtag_marshal(evbuf, tag, data, len);
}

#define DECODE_INT_INTERNAL(number, maxnibbles, pnumber, evbuf, offset) \
do {                                                                    \
        ev_uint8_t *data;                                               \
        ev_ssize_t len = evbuffer_get_length(evbuf) - offset;           \
        int nibbles = 0;                                                \
                                                                        \
        if (len <= 0)                                                   \
                return (-1);                                            \
                                                                        \
        /* XXX(niels): faster? */                                       \
        data = evbuffer_pullup(evbuf, offset + 1) + offset;             \
                                                                        \
        nibbles = ((data[0] & 0xf0) >> 4) + 1;                          \
        if (nibbles > maxnibbles || (nibbles >> 1) + 1 > len)           \
                return (-1);                                            \
        len = (nibbles >> 1) + 1;                                       \
                                                                        \
        data = evbuffer_pullup(evbuf, offset + len) + offset;           \
                                                                        \
        while (nibbles > 0) {                                           \
                number <<= 4;                                           \
                if (nibbles & 0x1)                                      \
                        number |= data[nibbles >> 1] & 0x0f;            \
                else                                                    \
                        number |= (data[nibbles >> 1] & 0xf0) >> 4;     \
                nibbles--;                                              \
        }                                                               \
                                                                        \
        *pnumber = number;                                              \
                                                                        \
        return (int)(len);                                              \
} while (0)

/* Internal: decode an integer from an evbuffer, without draining it.
 *  Only integers up to 32-bits are supported.
 *
 * @param evbuf the buffer to read from
 * @param offset an index into the buffer at which we should start reading.
 * @param pnumber a pointer to receive the integer.
 * @return The length of the number as encoded, or -1 on error.
 */

static int
decode_int_internal(ev_uint32_t *pnumber, struct evbuffer *evbuf, int offset)
{
        ev_uint32_t number = 0;
        DECODE_INT_INTERNAL(number, 8, pnumber, evbuf, offset);
}

static int
decode_int64_internal(ev_uint64_t *pnumber, struct evbuffer *evbuf, int offset)
{
        ev_uint64_t number = 0;
        DECODE_INT_INTERNAL(number, 16, pnumber, evbuf, offset);
}

int
evtag_decode_int(ev_uint32_t *pnumber, struct evbuffer *evbuf)
{
        int res = decode_int_internal(pnumber, evbuf, 0);
        if (res != -1)
                evbuffer_drain(evbuf, res);

        return (res == -1 ? -1 : 0);
}

int
evtag_decode_int64(ev_uint64_t *pnumber, struct evbuffer *evbuf)
{
        int res = decode_int64_internal(pnumber, evbuf, 0);
        if (res != -1)
                evbuffer_drain(evbuf, res);

        return (res == -1 ? -1 : 0);
}

int
evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag)
{
        return (decode_tag_internal(ptag, evbuf, 0 /* dodrain */));
}

int
evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength)
{
        int res, len;

        len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
        if (len == -1)
                return (-1);

        res = decode_int_internal(plength, evbuf, len);
        if (res == -1)
                return (-1);

        *plength += res + len;

        return (0);
}

int
evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength)
{
        int res, len;

        len = decode_tag_internal(NULL, evbuf, 0 /* dodrain */);
        if (len == -1)
                return (-1);

        res = decode_int_internal(plength, evbuf, len);
        if (res == -1)
                return (-1);

        return (0);
}

/* just unmarshals the header and returns the length of the remaining data */

int
evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag)
{
        ev_uint32_t len;

        if (decode_tag_internal(ptag, evbuf, 1 /* dodrain */) == -1)
                return (-1);
        if (evtag_decode_int(&len, evbuf) == -1)
                return (-1);

        if (evbuffer_get_length(evbuf) < len)
                return (-1);

        return (len);
}

int
evtag_consume(struct evbuffer *evbuf)
{
        int len;
        if ((len = evtag_unmarshal_header(evbuf, NULL)) == -1)
                return (-1);
        evbuffer_drain(evbuf, len);

        return (0);
}

/* Reads the data type from an event buffer */

int
evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag, struct evbuffer *dst)
{
        int len;

        if ((len = evtag_unmarshal_header(src, ptag)) == -1)
                return (-1);

        if (evbuffer_add(dst, evbuffer_pullup(src, len), len) == -1)
                return (-1);

        evbuffer_drain(src, len);

        return (len);
}

/* Marshaling for integers */

int
evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag,
    ev_uint32_t *pinteger)
{
        ev_uint32_t tag;
        ev_uint32_t len;
        int result;

        if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1)
                return (-1);
        if (need_tag != tag)
                return (-1);
        if (evtag_decode_int(&len, evbuf) == -1)
                return (-1);

        if (evbuffer_get_length(evbuf) < len)
                return (-1);

        result = decode_int_internal(pinteger, evbuf, 0);
        evbuffer_drain(evbuf, len);
        if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/
                return (-1);
        else
                return result;
}

int
evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag,
    ev_uint64_t *pinteger)
{
        ev_uint32_t tag;
        ev_uint32_t len;
        int result;

        if (decode_tag_internal(&tag, evbuf, 1 /* dodrain */) == -1)
                return (-1);
        if (need_tag != tag)
                return (-1);
        if (evtag_decode_int(&len, evbuf) == -1)
                return (-1);

        if (evbuffer_get_length(evbuf) < len)
                return (-1);

        result = decode_int64_internal(pinteger, evbuf, 0);
        evbuffer_drain(evbuf, len);
        if (result < 0 || (size_t)result > len) /* XXX Should this be != rather than > ?*/
                return (-1);
        else
                return result;
}

/* Unmarshal a fixed length tag */

int
evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag, void *data,
    size_t len)
{
        ev_uint32_t tag;
        int tag_len;

        /* Now unmarshal a tag and check that it matches the tag we want */
        if ((tag_len = evtag_unmarshal_header(src, &tag)) < 0 ||
            tag != need_tag)
                return (-1);

        if ((size_t)tag_len != len)
                return (-1);

        evbuffer_remove(src, data, len);
        return (0);
}

int
evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag,
    char **pstring)
{
        ev_uint32_t tag;
        int tag_len;

        if ((tag_len = evtag_unmarshal_header(evbuf, &tag)) == -1 ||
            tag != need_tag)
                return (-1);

        *pstring = mm_malloc(tag_len + 1);
        if (*pstring == NULL) {
                event_warn("%s: malloc", __func__);
                return -1;
        }
        evbuffer_remove(evbuf, *pstring, tag_len);
        (*pstring)[tag_len] = '\0';

        return (0);
}

int
evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag,
    struct timeval *ptv)
{
        ev_uint32_t tag;
        ev_uint32_t integer;
        int len, offset, offset2;
        int result = -1;

        if ((len = evtag_unmarshal_header(evbuf, &tag)) == -1)
                return (-1);
        if (tag != need_tag)
                goto done;
        if ((offset = decode_int_internal(&integer, evbuf, 0)) == -1)
                goto done;
        ptv->tv_sec = integer;
        if ((offset2 = decode_int_internal(&integer, evbuf, offset)) == -1)
                goto done;
        ptv->tv_usec = integer;
        if (offset + offset2 > len) /* XXX Should this be != instead of > ? */
                goto done;

        result = 0;
 done:
        evbuffer_drain(evbuf, len);
        return result;
}