haproxy/include/proto/spoe.h
Christopher Faulet 4ff3e574ac REORG: spoe: Move low-level encoding/decoding functions in dedicated header file
So, it will be easier to anyone to develop external services using these
functions.

SPOA example has been updated accordingly.
2017-03-09 15:32:55 +01:00

424 lines
10 KiB
C

/*
* include/proto/spoe.h
* Encoding/Decoding functions for the SPOE filters (and other helpers).
*
* Copyright (C) 2017 HAProxy Technologies, Christopher Faulet <cfaulet@haproxy.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_SPOE_H
#define _PROTO_SPOE_H
#include <types/spoe.h>
#include <proto/sample.h>
/* Encode the integer <i> into a varint (variable-length integer). The encoded
* value is copied in <*buf>. Here is the encoding format:
*
* 0 <= X < 240 : 1 byte (7.875 bits) [ XXXX XXXX ]
* 240 <= X < 2288 : 2 bytes (11 bits) [ 1111 XXXX ] [ 0XXX XXXX ]
* 2288 <= X < 264432 : 3 bytes (18 bits) [ 1111 XXXX ] [ 1XXX XXXX ] [ 0XXX XXXX ]
* 264432 <= X < 33818864 : 4 bytes (25 bits) [ 1111 XXXX ] [ 1XXX XXXX ]*2 [ 0XXX XXXX ]
* 33818864 <= X < 4328786160 : 5 bytes (32 bits) [ 1111 XXXX ] [ 1XXX XXXX ]*3 [ 0XXX XXXX ]
* ...
*
* On success, it returns the number of written bytes and <*buf> is moved after
* the encoded value. Otherwise, it returns -1. */
int
spoe_encode_varint(uint64_t i, char **buf, char *end)
{
unsigned char *p = (unsigned char *)*buf;
int r;
if (p >= (unsigned char *)end)
return -1;
if (i < 240) {
*p++ = i;
*buf = (char *)p;
return 1;
}
*p++ = (unsigned char)i | 240;
i = (i - 240) >> 4;
while (i >= 128) {
if (p >= (unsigned char *)end)
return -1;
*p++ = (unsigned char)i | 128;
i = (i - 128) >> 7;
}
if (p >= (unsigned char *)end)
return -1;
*p++ = (unsigned char)i;
r = ((char *)p - *buf);
*buf = (char *)p;
return r;
}
/* Decode a varint from <*buf> and save the decoded value in <*i>. See
* 'spoe_encode_varint' for details about varint.
* On success, it returns the number of read bytes and <*buf> is moved after the
* varint. Otherwise, it returns -1. */
int
spoe_decode_varint(char **buf, char *end, uint64_t *i)
{
unsigned char *p = (unsigned char *)*buf;
int r;
if (p >= (unsigned char *)end)
return -1;
*i = *p++;
if (*i < 240) {
*buf = (char *)p;
return 1;
}
r = 4;
do {
if (p >= (unsigned char *)end)
return -1;
*i += (uint64_t)*p << r;
r += 7;
} while (*p++ >= 128);
r = ((char *)p - *buf);
*buf = (char *)p;
return r;
}
/* Encode a buffer. Its length <len> is encoded as a varint, followed by a copy
* of <str>. It must have enough space in <*buf> to encode the buffer, else an
* error is triggered.
* On success, it returns <len> and <*buf> is moved after the encoded value. If
* an error occurred, it returns -1. */
int
spoe_encode_buffer(const char *str, size_t len, char **buf, char *end)
{
char *p = *buf;
int ret;
if (p >= end)
return -1;
if (!len) {
*p++ = 0;
*buf = p;
return 0;
}
ret = spoe_encode_varint(len, &p, end);
if (ret == -1 || p + len > end)
return -1;
memcpy(p, str, len);
*buf = p + len;
return len;
}
/* Encode a buffer, possibly partially. It does the same thing than
* 'spoe_encode_buffer', but if there is not enough space, it does not fail.
* On success, it returns the number of copied bytes and <*buf> is moved after
* the encoded value. If an error occured, it returns -1. */
int
spoe_encode_frag_buffer(const char *str, size_t len, char **buf, char *end)
{
char *p = *buf;
int ret;
if (p >= end)
return -1;
if (!len) {
*p++ = 0;
*buf = p;
return 0;
}
ret = spoe_encode_varint(len, &p, end);
if (ret == -1 || p >= end)
return -1;
ret = (p+len < end) ? len : (end - p);
memcpy(p, str, ret);
*buf = p + ret;
return ret;
}
/* Decode a buffer. The buffer length is decoded and saved in <*len>. <*str>
* points on the first byte of the buffer.
* On success, it returns the buffer length and <*buf> is moved after the
* encoded buffer. Otherwise, it returns -1. */
int
spoe_decode_buffer(char **buf, char *end, char **str, size_t *len)
{
char *p = *buf;
uint64_t sz;
int ret;
*str = NULL;
*len = 0;
ret = spoe_decode_varint(&p, end, &sz);
if (ret == -1 || p + sz > end)
return -1;
*str = p;
*len = sz;
*buf = p + sz;
return sz;
}
/* Encode a typed data using value in <smp>. On success, it returns the number
* of copied bytes and <*buf> is moved after the encoded value. If an error
* occured, it returns -1.
*
* If the value is too big to be encoded, depending on its type, then encoding
* failed or the value is partially encoded. Only strings and binaries can be
* partially encoded. In this case, the offset <*off> is updated to known how
* many bytes has been encoded. If <*off> is zero at the end, it means that all
* data has been encoded. */
int
spoe_encode_data(struct sample *smp, unsigned int *off, char **buf, char *end)
{
char *p = *buf;
int ret;
if (p >= end)
return -1;
if (smp == NULL) {
*p++ = SPOE_DATA_T_NULL;
goto end;
}
switch (smp->data.type) {
case SMP_T_BOOL:
*p = SPOE_DATA_T_BOOL;
*p++ |= ((!smp->data.u.sint) ? SPOE_DATA_FL_FALSE : SPOE_DATA_FL_TRUE);
break;
case SMP_T_SINT:
*p++ = SPOE_DATA_T_INT64;
if (spoe_encode_varint(smp->data.u.sint, &p, end) == -1)
return -1;
break;
case SMP_T_IPV4:
if (p + 5 > end)
return -1;
*p++ = SPOE_DATA_T_IPV4;
memcpy(p, &smp->data.u.ipv4, 4);
p += 4;
break;
case SMP_T_IPV6:
if (p + 17 > end)
return -1;
*p++ = SPOE_DATA_T_IPV6;
memcpy(p, &smp->data.u.ipv6, 16);
p += 16;
break;
case SMP_T_STR:
case SMP_T_BIN: {
struct chunk *chk = &smp->data.u.str;
/* Here, we need to know if the sample has already been
* partially encoded. If yes, we only need to encode the
* remaining, <*off> reprensenting the number of bytes
* already encoded. */
if (!*off) {
/* First evaluation of the sample : encode the
* type (string or binary), the buffer length
* (as a varint) and at least 1 byte of the
* buffer. */
struct chunk *chk = &smp->data.u.str;
*p++ = (smp->data.type == SMP_T_STR)
? SPOE_DATA_T_STR
: SPOE_DATA_T_BIN;
ret = spoe_encode_frag_buffer(chk->str, chk->len, &p, end);
if (ret == -1)
return -1;
}
else {
/* The sample has been fragmented, encode remaining data */
ret = MIN(chk->len - *off, end - p);
memcpy(p, chk->str + *off, ret);
p += ret;
}
/* Now update <*off> */
if (ret + *off != chk->len)
*off += ret;
else
*off = 0;
break;
}
case SMP_T_METH: {
char *m;
size_t len;
*p++ = SPOE_DATA_T_STR;
switch (smp->data.u.meth.meth) {
case HTTP_METH_OPTIONS: m = "OPTIONS"; len = 7; break;
case HTTP_METH_GET : m = "GET"; len = 3; break;
case HTTP_METH_HEAD : m = "HEAD"; len = 4; break;
case HTTP_METH_POST : m = "POST"; len = 4; break;
case HTTP_METH_PUT : m = "PUT"; len = 3; break;
case HTTP_METH_DELETE : m = "DELETE"; len = 6; break;
case HTTP_METH_TRACE : m = "TRACE"; len = 5; break;
case HTTP_METH_CONNECT: m = "CONNECT"; len = 7; break;
default :
m = smp->data.u.meth.str.str;
len = smp->data.u.meth.str.len;
}
if (spoe_encode_buffer(m, len, &p, end) == -1)
return -1;
break;
}
default:
*p++ = SPOE_DATA_T_NULL;
break;
}
end:
ret = (p - *buf);
*buf = p;
return ret;
}
/* Skip a typed data. If an error occurred, -1 is returned, otherwise the number
* of skipped bytes is returned and the <*buf> is moved after skipped data.
*
* A types data is composed of a type (1 byte) and corresponding data:
* - boolean: non additional data (0 bytes)
* - integers: a variable-length integer (see spoe_decode_varint)
* - ipv4: 4 bytes
* - ipv6: 16 bytes
* - binary and string: a buffer prefixed by its size, a variable-length
* integer (see spoe_decode_buffer) */
int
spoe_skip_data(char **buf, char *end)
{
char *str, *p = *buf;
int type, ret;
size_t sz;
uint64_t v;
if (p >= end)
return -1;
type = *p++;
switch (type & SPOE_DATA_T_MASK) {
case SPOE_DATA_T_BOOL:
break;
case SPOE_DATA_T_INT32:
case SPOE_DATA_T_INT64:
case SPOE_DATA_T_UINT32:
case SPOE_DATA_T_UINT64:
if (spoe_decode_varint(&p, end, &v) == -1)
return -1;
break;
case SPOE_DATA_T_IPV4:
if (p+4 > end)
return -1;
p += 4;
break;
case SPOE_DATA_T_IPV6:
if (p+16 > end)
return -1;
p += 16;
break;
case SPOE_DATA_T_STR:
case SPOE_DATA_T_BIN:
/* All the buffer must be skipped */
if (spoe_decode_buffer(&p, end, &str, &sz) == -1)
return -1;
break;
}
ret = (p - *buf);
*buf = p;
return ret;
}
/* Decode a typed data and fill <smp>. If an error occurred, -1 is returned,
* otherwise the number of read bytes is returned and <*buf> is moved after the
* decoded data. See spoe_skip_data for details. */
int
spoe_decode_data(char **buf, char *end, struct sample *smp)
{
char *str, *p = *buf;
int type, r = 0;
size_t sz;
if (p >= end)
return -1;
type = *p++;
switch (type & SPOE_DATA_T_MASK) {
case SPOE_DATA_T_BOOL:
smp->data.u.sint = ((type & SPOE_DATA_FL_MASK) == SPOE_DATA_FL_TRUE);
smp->data.type = SMP_T_BOOL;
break;
case SPOE_DATA_T_INT32:
case SPOE_DATA_T_INT64:
case SPOE_DATA_T_UINT32:
case SPOE_DATA_T_UINT64:
if (spoe_decode_varint(&p, end, (uint64_t *)&smp->data.u.sint) == -1)
return -1;
smp->data.type = SMP_T_SINT;
break;
case SPOE_DATA_T_IPV4:
if (p+4 > end)
return -1;
smp->data.type = SMP_T_IPV4;
memcpy(&smp->data.u.ipv4, p, 4);
p += 4;
break;
case SPOE_DATA_T_IPV6:
if (p+16 > end)
return -1;
memcpy(&smp->data.u.ipv6, p, 16);
smp->data.type = SMP_T_IPV6;
p += 16;
break;
case SPOE_DATA_T_STR:
case SPOE_DATA_T_BIN:
/* All the buffer must be decoded */
if (spoe_decode_buffer(&p, end, &str, &sz) == -1)
return -1;
smp->data.u.str.str = str;
smp->data.u.str.len = sz;
smp->data.type = (type == SPOE_DATA_T_STR) ? SMP_T_STR : SMP_T_BIN;
break;
}
r = (p - *buf);
*buf = p;
return r;
}
#endif /* _PROTO_SPOE_H */