tcpdump/print-resp.c
Francois-Xavier Le Bail b38f324af9 Add a summary comment in all other printers
Moreover:
Remove some redundant comments
Update some summary comments
Update the specification URL for ATA over Ethernet (AoE) protocol
2016-08-15 22:42:38 +02:00

375 lines
11 KiB
C

/*
* Copyright (c) 2015 The TCPDUMP project
* 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 COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDER 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.
*
* Initial contribution by Andrew Darqui (andrew.darqui@gmail.com).
*/
/* \summary: REdis Serialization Protocol (RESP) printer */
#define NETDISSECT_REWORKED
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <netdissect-stdinc.h>
#include "netdissect.h"
#include <limits.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include "extract.h"
static const char tstr[] = " [|RESP]";
/*
* For information regarding RESP, see: http://redis.io/topics/protocol
*/
#define RESP_SIMPLE_STRING '+'
#define RESP_ERROR '-'
#define RESP_INTEGER ':'
#define RESP_BULK_STRING '$'
#define RESP_ARRAY '*'
#define resp_print_empty(ndo) ND_PRINT((ndo, " empty"))
#define resp_print_null(ndo) ND_PRINT((ndo, " null"))
#define resp_print_invalid(ndo) ND_PRINT((ndo, " invalid"))
void resp_print(netdissect_options *, const u_char *, u_int);
static int resp_parse(netdissect_options *, register const u_char *, int);
static int resp_print_string_error_integer(netdissect_options *, register const u_char *, int);
static int resp_print_simple_string(netdissect_options *, register const u_char *, int);
static int resp_print_integer(netdissect_options *, register const u_char *, int);
static int resp_print_error(netdissect_options *, register const u_char *, int);
static int resp_print_bulk_string(netdissect_options *, register const u_char *, int);
static int resp_print_bulk_array(netdissect_options *, register const u_char *, int);
static int resp_print_inline(netdissect_options *, register const u_char *, int);
/*
* MOVE_FORWARD:
* Attempts to move our 'ptr' forward until a \r\n is found,
* while also making sure we don't exceed the buffer 'len'.
* If we exceed, jump to trunc.
*/
#define MOVE_FORWARD(ptr, len) \
while(*ptr != '\r' && *(ptr+1) != '\n') { ND_TCHECK2(*ptr, 2); ptr++; len--; }
/*
* MOVE_FORWARD_CR_OR_LF
* Attempts to move our 'ptr' forward until a \r or \n is found,
* while also making sure we don't exceed the buffer 'len'.
* If we exceed, jump to trunc.
*/
#define MOVE_FORWARD_CR_OR_LF(ptr, len) \
while(*ptr != '\r' && *ptr != '\n') { ND_TCHECK(*ptr); ptr++; len--; }
/*
* CONSUME_CR_OR_LF
* Consume all consecutive \r and \n bytes.
* If we exceed 'len', jump to trunc.
*/
#define CONSUME_CR_OR_LF(ptr, len) \
while (*ptr == '\r' || *ptr == '\n') { ND_TCHECK(*ptr); ptr++; len--; }
/*
* INCBY
* Attempts to increment our 'ptr' by 'increment' bytes.
* If our increment exceeds the buffer length (len - increment),
* bail out by jumping to the trunc goto tag.
*/
#define INCBY(ptr, increment, len) \
{ ND_TCHECK2(*ptr, increment); ptr+=increment; len-=increment; }
/*
* INC1
* Increment our ptr by 1 byte.
* Most often used to skip an opcode (+-:*$ etc)
*/
#define INC1(ptr, len) INCBY(ptr, 1, len)
/*
* INC2
* Increment our ptr by 2 bytes.
* Most often used to skip CRLF (\r\n).
*/
#define INC2(ptr, len) INCBY(ptr, 2, len)
/*
* TEST_RET_LEN
* If ret_len is < 0, jump to the trunc tag which returns (-1)
* and 'bubbles up' to printing tstr. Otherwise, return ret_len.
*/
#define TEST_RET_LEN(rl) \
if (rl < 0) { goto trunc; } else { return rl; }
/*
* TEST_RET_LEN_NORETURN
* If ret_len is < 0, jump to the trunc tag which returns (-1)
* and 'bubbles up' to printing tstr. Otherwise, continue onward.
*/
#define TEST_RET_LEN_NORETURN(rl) \
if (rl < 0) { goto trunc; }
/*
* RESP_PRINT_SEGMENT
* Prints a segment in the form of: ' "<stuff>"\n"
*/
#define RESP_PRINT_SEGMENT(_ndo, _bp, _len) \
ND_PRINT((_ndo, " \"")); \
if (fn_printn(_ndo, _bp, _len, _ndo->ndo_snapend)) \
goto trunc; \
fn_print_char(_ndo, '"');
void
resp_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
int ret_len = 0, length_cur = length;
if(!bp || length <= 0)
return;
ND_PRINT((ndo, ": RESP"));
while (length_cur > 0) {
/*
* This block supports redis pipelining.
* For example, multiple operations can be pipelined within the same string:
* "*2\r\n\$4\r\nINCR\r\n\$1\r\nz\r\n*2\r\n\$4\r\nINCR\r\n\$1\r\nz\r\n*2\r\n\$4\r\nINCR\r\n\$1\r\nz\r\n"
* or
* "PING\r\nPING\r\nPING\r\n"
* In order to handle this case, we must try and parse 'bp' until
* 'length' bytes have been processed or we reach a trunc condition.
*/
ret_len = resp_parse(ndo, bp, length_cur);
TEST_RET_LEN_NORETURN(ret_len);
bp += ret_len;
length_cur -= ret_len;
}
return;
trunc:
ND_PRINT((ndo, "%s", tstr));
}
static int
resp_parse(netdissect_options *ndo, register const u_char *bp, int length)
{
int ret_len = 0;
u_char op = *bp;
ND_TCHECK(*bp);
switch(op) {
case RESP_SIMPLE_STRING: ret_len = resp_print_simple_string(ndo, bp, length); break;
case RESP_INTEGER: ret_len = resp_print_integer(ndo, bp, length); break;
case RESP_ERROR: ret_len = resp_print_error(ndo, bp, length); break;
case RESP_BULK_STRING: ret_len = resp_print_bulk_string(ndo, bp, length); break;
case RESP_ARRAY: ret_len = resp_print_bulk_array(ndo, bp, length); break;
default: ret_len = resp_print_inline(ndo, bp, length); break;
}
TEST_RET_LEN(ret_len);
trunc:
return (-1);
}
static int
resp_print_simple_string(netdissect_options *ndo, register const u_char *bp, int length) {
return resp_print_string_error_integer(ndo, bp, length);
}
static int
resp_print_integer(netdissect_options *ndo, register const u_char *bp, int length) {
return resp_print_string_error_integer(ndo, bp, length);
}
static int
resp_print_error(netdissect_options *ndo, register const u_char *bp, int length) {
return resp_print_string_error_integer(ndo, bp, length);
}
static int
resp_print_string_error_integer(netdissect_options *ndo, register const u_char *bp, int length) {
int length_cur = length, len, ret_len = 0;
const u_char *bp_ptr = bp;
/*
* MOVE_FORWARD moves past the string that follows the (+-;) opcodes
* +OK\r\n
* -ERR ...\r\n
* :02912309\r\n
*/
MOVE_FORWARD(bp_ptr, length_cur);
len = (bp_ptr - bp);
ND_TCHECK2(*bp, len);
RESP_PRINT_SEGMENT(ndo, bp+1, len-1);
ret_len = len /*<1byte>+<string>*/ + 2 /*<CRLF>*/;
TEST_RET_LEN(ret_len);
trunc:
return (-1);
}
static int
resp_print_bulk_string(netdissect_options *ndo, register const u_char *bp, int length) {
int length_cur = length, string_len;
long strtol_ret;
char *p;
ND_TCHECK(*bp);
/* opcode: '$' */
INC1(bp, length_cur);
ND_TCHECK(*bp);
/* <length> */
errno = 0;
strtol_ret = strtol((const char *)bp, &p, 10);
if (errno != 0 || p == (const char *)bp || strtol_ret < -1 ||
strtol_ret > INT_MAX)
string_len = -2; /* invalid */
else
string_len = (int)strtol_ret;
/* move to \r\n */
MOVE_FORWARD(bp, length_cur);
/* \r\n */
INC2(bp, length_cur);
if (string_len > 0) {
/* Byte string of length string_len */
ND_TCHECK2(*bp, string_len);
RESP_PRINT_SEGMENT(ndo, bp, string_len);
} else {
switch(string_len) {
case 0: resp_print_empty(ndo); break;
case (-1): {
/* This is the NULL response. It follows a different pattern: $-1\r\n */
resp_print_null(ndo);
TEST_RET_LEN(length - length_cur);
/* returned ret_len or jumped to trunc */
}
default: resp_print_invalid(ndo); break;
}
}
/* <string> */
INCBY(bp, string_len, length_cur);
/* \r\n */
INC2(bp, length_cur);
TEST_RET_LEN(length - length_cur);
trunc:
return (-1);
}
static int
resp_print_bulk_array(netdissect_options *ndo, register const u_char *bp, int length) {
int length_cur = length, array_len, i, ret_len = 0;
long strtol_ret;
char *p;
ND_TCHECK(*bp);
/* opcode: '*' */
INC1(bp, length_cur);
ND_TCHECK(*bp);
/* <array_length> */
errno = 0;
strtol_ret = strtol((const char *)bp, &p, 10);
if (errno != 0 || p == (const char *)bp || strtol_ret < -1 ||
strtol_ret > INT_MAX)
array_len = -2; /* invalid */
else
array_len = (int)strtol_ret;
/* move to \r\n */
MOVE_FORWARD(bp, length_cur);
/* \r\n */
INC2(bp, length_cur);
if (array_len > 0) {
/* non empty array */
for (i = 0; i < array_len; i++) {
ret_len = resp_parse(ndo, bp, length_cur);
TEST_RET_LEN_NORETURN(ret_len);
bp += ret_len;
length_cur -= ret_len;
TEST_RET_LEN_NORETURN(length - length_cur);
}
} else {
/* empty, null, or invalid */
switch(array_len) {
case 0: resp_print_empty(ndo); break;
case (-1): resp_print_null(ndo); break;
default: resp_print_invalid(ndo); break;
}
}
TEST_RET_LEN(length - length_cur);
trunc:
return (-1);
}
static int
resp_print_inline(netdissect_options *ndo, register const u_char *bp, int length) {
int length_cur = length, len;
const u_char *bp_ptr;
/*
* Inline commands are simply 'strings' followed by \r or \n or both.
* Redis will do it's best to split/parse these strings.
* This feature of redis is implemented to support the ability of
* command parsing from telnet/nc sessions etc.
*
* <string><\r||\n||\r\n...>
*/
CONSUME_CR_OR_LF(bp, length_cur);
bp_ptr = bp;
MOVE_FORWARD_CR_OR_LF(bp_ptr, length_cur);
len = (bp_ptr - bp);
ND_TCHECK2(*bp, len);
RESP_PRINT_SEGMENT(ndo, bp, len);
CONSUME_CR_OR_LF(bp_ptr, length_cur);
TEST_RET_LEN(length - length_cur);
trunc:
return (-1);
}