option.c
Go to the documentation of this file.
/*
* option.c -- helpers for handling options in CoAP PDUs
*
* Copyright (C) 2010-2013 Olaf Bergmann <bergmann@tzi.org>
*
* This file is part of the CoAP library libcoap. Please see
* README for terms of use.
*/
#include "coap_internal.h"
#include <stdio.h>
#include <string.h>
#define ADVANCE_OPT(o,e,step) if ((e) < step) { \
coap_log(LOG_DEBUG, "cannot advance opt past end\n"); \
return 0; \
} else { \
(e) -= step; \
(o) = ((o)) + step; \
}
/*
* Used to prevent access to *opt when pointing to after end of buffer
* after doing a ADVANCE_OPT()
*/
#define ADVANCE_OPT_CHECK(o,e,step) do { \
ADVANCE_OPT(o,e,step); \
if ((e) < 1) \
return 0; \
} while (0)
size_t
coap_opt_parse(const coap_opt_t *opt, size_t length, coap_option_t *result) {
const coap_opt_t *opt_start = opt; /* store where parsing starts */
assert(opt); assert(result);
if (length < 1)
return 0;
result->delta = (*opt & 0xf0) >> 4;
result->length = *opt & 0x0f;
switch(result->delta) {
case 15:
if (*opt != COAP_PAYLOAD_START) {
coap_log(LOG_DEBUG, "ignored reserved option delta 15\n");
}
return 0;
case 14:
/* Handle two-byte value: First, the MSB + 269 is stored as delta value.
* After that, the option pointer is advanced to the LSB which is handled
* just like case delta == 13. */
ADVANCE_OPT_CHECK(opt,length,1);
result->delta = ((*opt & 0xff) << 8) + 269;
if (result->delta < 269) {
coap_log(LOG_DEBUG, "delta too large\n");
return 0;
}
/* fall through */
case 13:
ADVANCE_OPT_CHECK(opt,length,1);
result->delta += *opt & 0xff;
break;
default:
;
}
switch(result->length) {
case 15:
coap_log(LOG_DEBUG, "found reserved option length 15\n");
return 0;
case 14:
/* Handle two-byte value: First, the MSB + 269 is stored as delta value.
* After that, the option pointer is advanced to the LSB which is handled
* just like case delta == 13. */
ADVANCE_OPT_CHECK(opt,length,1);
result->length = ((*opt & 0xff) << 8) + 269;
/* fall through */
case 13:
ADVANCE_OPT_CHECK(opt,length,1);
result->length += *opt & 0xff;
break;
default:
;
}
/* ADVANCE_OPT() is correct here */
ADVANCE_OPT(opt,length,1);
/* opt now points to value, if present */
result->value = opt;
if (length < result->length) {
coap_log(LOG_DEBUG, "invalid option length\n");
return 0;
}
#undef ADVANCE_OPT
#undef ADVANCE_OPT_CHECK
return (opt + result->length) - opt_start;
}
coap_opt_iterator_t *
coap_option_iterator_init(const coap_pdu_t *pdu, coap_opt_iterator_t *oi,
const coap_opt_filter_t filter) {
assert(pdu);
assert(pdu->token);
assert(oi);
memset(oi, 0, sizeof(coap_opt_iterator_t));
oi->next_option = pdu->token + pdu->token_length;
if (pdu->token + pdu->used_size <= oi->next_option) {
oi->bad = 1;
return NULL;
}
oi->length = pdu->used_size - pdu->token_length;
if (filter) {
memcpy(oi->filter, filter, sizeof(coap_opt_filter_t));
oi->filtered = 1;
}
return oi;
}
COAP_STATIC_INLINE int
opt_finished(coap_opt_iterator_t *oi) {
assert(oi);
if (oi->bad || oi->length == 0 ||
!oi->next_option || *oi->next_option == COAP_PAYLOAD_START) {
oi->bad = 1;
}
return oi->bad;
}
coap_opt_t *
coap_option_next(coap_opt_iterator_t *oi) {
coap_option_t option;
coap_opt_t *current_opt = NULL;
size_t optsize;
int b; /* to store result of coap_option_getb() */
assert(oi);
if (opt_finished(oi))
return NULL;
while (1) {
/* oi->option always points to the next option to deliver; as
* opt_finished() filters out any bad conditions, we can assume that
* oi->option is valid. */
current_opt = oi->next_option;
/* Advance internal pointer to next option, skipping any option that
* is not included in oi->filter. */
optsize = coap_opt_parse(oi->next_option, oi->length, &option);
if (optsize) {
assert(optsize <= oi->length);
oi->next_option += optsize;
oi->length -= optsize;
oi->type += option.delta;
} else { /* current option is malformed */
oi->bad = 1;
return NULL;
}
/* Exit the while loop when:
* - no filtering is done at all
* - the filter matches for the current option
* - the filter is too small for the current option number
*/
if (!oi->filtered ||
(b = coap_option_getb(oi->filter, oi->type)) > 0)
break;
else if (b < 0) { /* filter too small, cannot proceed */
oi->bad = 1;
return NULL;
}
}
return current_opt;
}
coap_opt_t *
coap_check_option(coap_pdu_t *pdu, uint16_t type,
coap_opt_iterator_t *oi) {
coap_opt_filter_t f;
coap_option_filter_clear(f);
coap_option_setb(f, type);
coap_option_iterator_init(pdu, oi, f);
return coap_option_next(oi);
}
uint16_t
coap_opt_delta(const coap_opt_t *opt) {
uint16_t n;
n = (*opt++ & 0xf0) >> 4;
switch (n) {
case 15: /* error */
coap_log(LOG_WARNING, "coap_opt_delta: illegal option delta\n");
/* This case usually should not happen, hence we do not have a
* proper way to indicate an error. */
return 0;
case 14:
/* Handle two-byte value: First, the MSB + 269 is stored as delta value.
* After that, the option pointer is advanced to the LSB which is handled
* just like case delta == 13. */
n = ((*opt++ & 0xff) << 8) + 269;
/* fall through */
case 13:
n += *opt & 0xff;
break;
default: /* n already contains the actual delta value */
;
}
return n;
}
uint16_t
coap_opt_length(const coap_opt_t *opt) {
uint16_t length;
length = *opt & 0x0f;
switch (*opt & 0xf0) {
case 0xf0:
coap_log(LOG_DEBUG, "illegal option delta\n");
return 0;
case 0xe0:
++opt;
/* fall through */
/* to skip another byte */
case 0xd0:
++opt;
/* fall through */
/* to skip another byte */
default:
++opt;
}
switch (length) {
case 0x0f:
coap_log(LOG_DEBUG, "illegal option length\n");
return 0;
case 0x0e:
length = (*opt++ << 8) + 269;
/* fall through */
case 0x0d:
length += *opt++;
break;
default:
;
}
return length;
}
const uint8_t *
coap_opt_value(const coap_opt_t *opt) {
size_t ofs = 1;
switch (*opt & 0xf0) {
case 0xf0:
coap_log(LOG_DEBUG, "illegal option delta\n");
return 0;
case 0xe0:
++ofs;
/* fall through */
case 0xd0:
++ofs;
break;
default:
;
}
switch (*opt & 0x0f) {
case 0x0f:
coap_log(LOG_DEBUG, "illegal option length\n");
return 0;
case 0x0e:
++ofs;
/* fall through */
case 0x0d:
++ofs;
break;
default:
;
}
return (const uint8_t *)opt + ofs;
}
size_t
coap_opt_size(const coap_opt_t *opt) {
coap_option_t option;
/* we must assume that opt is encoded correctly */
return coap_opt_parse(opt, (size_t)-1, &option);
}
size_t
coap_opt_setheader(coap_opt_t *opt, size_t maxlen,
uint16_t delta, size_t length) {
size_t skip = 0;
assert(opt);
if (maxlen == 0) /* need at least one byte */
return 0;
if (delta < 13) {
opt[0] = (coap_opt_t)(delta << 4);
} else if (delta < 269) {
if (maxlen < 2) {
coap_log(LOG_DEBUG, "insufficient space to encode option delta %d\n",
delta);
return 0;
}
opt[0] = 0xd0;
opt[++skip] = (coap_opt_t)(delta - 13);
} else {
if (maxlen < 3) {
coap_log(LOG_DEBUG, "insufficient space to encode option delta %d\n",
delta);
return 0;
}
opt[0] = 0xe0;
opt[++skip] = ((delta - 269) >> 8) & 0xff;
opt[++skip] = (delta - 269) & 0xff;
}
if (length < 13) {
opt[0] |= length & 0x0f;
} else if (length < 269) {
if (maxlen < skip + 2) {
coap_log(LOG_DEBUG, "insufficient space to encode option length %zu\n",
length);
return 0;
}
opt[0] |= 0x0d;
opt[++skip] = (coap_opt_t)(length - 13);
} else {
if (maxlen < skip + 3) {
coap_log(LOG_DEBUG, "insufficient space to encode option delta %d\n",
delta);
return 0;
}
opt[0] |= 0x0e;
opt[++skip] = ((length - 269) >> 8) & 0xff;
opt[++skip] = (length - 269) & 0xff;
}
return skip + 1;
}
size_t
coap_opt_encode_size(uint16_t delta, size_t length) {
size_t n = 1;
if (delta >= 13) {
if (delta < 269)
n += 1;
else
n += 2;
}
if (length >= 13) {
if (length < 269)
n += 1;
else
n += 2;
}
return n + length;
}
size_t
coap_opt_encode(coap_opt_t *opt, size_t maxlen, uint16_t delta,
const uint8_t *val, size_t length) {
size_t l = 1;
l = coap_opt_setheader(opt, maxlen, delta, length);
assert(l <= maxlen);
if (!l) {
coap_log(LOG_DEBUG, "coap_opt_encode: cannot set option header\n");
return 0;
}
maxlen -= l;
opt += l;
if (maxlen < length) {
coap_log(LOG_DEBUG, "coap_opt_encode: option too large for buffer\n");
return 0;
}
if (val) /* better be safe here */
memcpy(opt, val, length);
return l + length;
}
/* coap_opt_filter_t has the following internal structure: */
typedef struct {
uint16_t mask;
#define LONG_MASK ((1 << COAP_OPT_FILTER_LONG) - 1)
#define SHORT_MASK \
(~LONG_MASK & ((1 << (COAP_OPT_FILTER_LONG + COAP_OPT_FILTER_SHORT)) - 1))
uint16_t long_opts[COAP_OPT_FILTER_LONG];
uint8_t short_opts[COAP_OPT_FILTER_SHORT];
} opt_filter;
COAP_STATIC_INLINE int
is_long_option(uint16_t type) { return type > 255; }
enum filter_op_t { FILTER_SET, FILTER_CLEAR, FILTER_GET };
static int
coap_option_filter_op(coap_opt_filter_t filter,
uint16_t type,
enum filter_op_t op) {
size_t lindex = 0;
opt_filter *of = (opt_filter *)filter;
uint16_t nr, mask = 0;
if (is_long_option(type)) {
mask = LONG_MASK;
for (nr = 1; lindex < COAP_OPT_FILTER_LONG; nr <<= 1, lindex++) {
if (((of->mask & nr) > 0) && (of->long_opts[lindex] == type)) {
if (op == FILTER_CLEAR) {
of->mask &= ~nr;
}
return 1;
}
}
} else {
mask = SHORT_MASK;
for (nr = 1 << COAP_OPT_FILTER_LONG; lindex < COAP_OPT_FILTER_SHORT;
nr <<= 1, lindex++) {
if (((of->mask & nr) > 0) && (of->short_opts[lindex] == (type & 0xff))) {
if (op == FILTER_CLEAR) {
of->mask &= ~nr;
}
return 1;
}
}
}
/* type was not found, so there is nothing to do if op is CLEAR or GET */
if ((op == FILTER_CLEAR) || (op == FILTER_GET)) {
return 0;
}
/* handle FILTER_SET: */
lindex = coap_fls(~of->mask & mask);
if (!lindex) {
return 0;
}
if (is_long_option(type)) {
of->long_opts[lindex - 1] = type;
} else {
of->short_opts[lindex - COAP_OPT_FILTER_LONG - 1] = (uint8_t)type;
}
of->mask |= 1 << (lindex - 1);
return 1;
}
int
coap_option_filter_set(coap_opt_filter_t filter, uint16_t type) {
return coap_option_filter_op(filter, type, FILTER_SET);
}
int
coap_option_filter_unset(coap_opt_filter_t filter, uint16_t type) {
return coap_option_filter_op(filter, type, FILTER_CLEAR);
}
int
coap_option_filter_get(coap_opt_filter_t filter, uint16_t type) {
/* Ugly cast to make the const go away (FILTER_GET wont change filter
* but as _set and _unset do, the function does not take a const). */
return coap_option_filter_op((uint16_t *)filter, type, FILTER_GET);
}
coap_optlist_t *
coap_new_optlist(uint16_t number,
size_t length,
const uint8_t *data
) {
coap_optlist_t *node;
node = coap_malloc_type(COAP_OPTLIST, sizeof(coap_optlist_t) + length);
if (node) {
memset(node, 0, (sizeof(coap_optlist_t) + length));
node->number = number;
node->length = length;
node->data = (uint8_t *)&node[1];
memcpy(node->data, data, length);
} else {
coap_log(LOG_WARNING, "coap_new_optlist: malloc failure\n");
}
return node;
}
static int
order_opts(void *a, void *b) {
coap_optlist_t *o1 = (coap_optlist_t *)a;
coap_optlist_t *o2 = (coap_optlist_t *)b;
if (!a || !b)
return a < b ? -1 : 1;
return (int)(o1->number - o2->number);
}
int
coap_add_optlist_pdu(coap_pdu_t *pdu, coap_optlist_t** options) {
coap_optlist_t *opt;
if (options && *options) {
/* sort options for delta encoding */
LL_SORT((*options), order_opts);
LL_FOREACH((*options), opt) {
coap_add_option(pdu, opt->number, opt->length, opt->data);
}
return 1;
}
return 0;
}
int
coap_insert_optlist(coap_optlist_t **head, coap_optlist_t *node) {
if (!node) {
coap_log(LOG_DEBUG, "optlist not provided\n");
} else {
/* must append at the list end to avoid re-ordering of
* options during sort */
LL_APPEND((*head), node);
}
return node != NULL;
}
static int
coap_internal_delete(coap_optlist_t *node) {
if (node) {
coap_free_type(COAP_OPTLIST, node);
}
return 1;
}
void
coap_delete_optlist(coap_optlist_t *queue) {
coap_optlist_t *elt, *tmp;
if (!queue)
return;
LL_FOREACH_SAFE(queue, elt, tmp) {
coap_internal_delete(elt);
}
}
LONG_MASK
#define LONG_MASK
Definition: option.c:428
LL_FOREACH
#define LL_FOREACH(head, el)
Definition: utlist.h:413
coap_optlist_t::length
size_t length
the option value length
Definition: option.h:411
opt_filter::mask
uint16_t mask
Definition: option.c:426
SHORT_MASK
#define SHORT_MASK
Definition: option.c:429
coap_opt_t
uint8_t coap_opt_t
Use byte-oriented access methods here because sliding a complex struct coap_opt_t over the data buffe...
Definition: option.h:25
COAP_OPTLIST
Definition: mem.h:45
coap_option_setb
COAP_STATIC_INLINE int coap_option_setb(coap_opt_filter_t filter, uint16_t type)
Sets the corresponding bit for type in filter.
Definition: option.h:183
COAP_OPT_FILTER_LONG
#define COAP_OPT_FILTER_LONG
The number of option types above 255 that can be stored in an option filter.
Definition: option.h:84
coap_insert_optlist
int coap_insert_optlist(coap_optlist_t **head, coap_optlist_t *node)
Adds optlist to the given optlist_chain.
Definition: option.c:589
opt_filter
Definition: option.c:425
opt_finished
COAP_STATIC_INLINE int opt_finished(coap_opt_iterator_t *oi)
Definition: option.c:134
FILTER_SET
Definition: option.c:441
coap_internal_delete
static int coap_internal_delete(coap_optlist_t *node)
Definition: option.c:602
coap_option_t::value
const uint8_t * value
Definition: option.h:34
coap_opt_iterator_t::length
size_t length
remaining length of PDU
Definition: option.h:238
coap_option_filter_set
int coap_option_filter_set(coap_opt_filter_t filter, uint16_t type)
Sets the corresponding entry for type in filter.
Definition: option.c:523
filter_op_t
filter_op_t
Operation specifiers for coap_filter_op().
Definition: option.c:441
LOG_DEBUG
Debug.
Definition: coap_debug.h:55
coap_option_next
coap_opt_t * coap_option_next(coap_opt_iterator_t *oi)
Updates the iterator oi to point to the next option.
Definition: option.c:146
coap_opt_iterator_t::filter
coap_opt_filter_t filter
option filter
Definition: option.h:243
coap_fls
int coap_fls(unsigned int i)
Definition: encode.c:13
coap_opt_iterator_t::type
uint16_t type
decoded option type
Definition: option.h:239
COAP_OPT_FILTER_SHORT
#define COAP_OPT_FILTER_SHORT
The number of option types below 256 that can be stored in an option filter.
Definition: option.h:76
ADVANCE_OPT_CHECK
#define ADVANCE_OPT_CHECK(o, e, step)
Definition: option.c:28
coap_delete_optlist
void coap_delete_optlist(coap_optlist_t *queue)
Removes all entries from the optlist_chain, freeing off their memory usage.
Definition: option.c:610
coap_optlist_t
Representation of chained list of CoAP options to install.
Definition: option.h:408
coap_opt_encode_size
size_t coap_opt_encode_size(uint16_t delta, size_t length)
Compute storage bytes needed for an option with given delta and length.
Definition: option.c:377
coap_check_option
coap_opt_t * coap_check_option(coap_pdu_t *pdu, uint16_t type, coap_opt_iterator_t *oi)
Retrieves the first option of type type from pdu.
Definition: option.c:196
coap_option_t::delta
uint16_t delta
Definition: option.h:32
coap_pdu_t
structure for CoAP PDUs token, if any, follows the fixed size header, then options until payload mark...
Definition: pdu.h:287
coap_option_filter_get
int coap_option_filter_get(coap_opt_filter_t filter, uint16_t type)
Checks if type is contained in filter.
Definition: option.c:533
coap_opt_length
uint16_t coap_opt_length(const coap_opt_t *opt)
Returns the length of the given option.
Definition: option.c:238
coap_option_t::length
size_t length
Definition: option.h:33
FILTER_CLEAR
Definition: option.c:441
LOG_WARNING
Warning.
Definition: coap_debug.h:52
coap_option_t
Representation of CoAP options.
Definition: option.h:31
FILTER_GET
Definition: option.c:441
coap_opt_delta
uint16_t coap_opt_delta(const coap_opt_t *opt)
Decodes the delta value of the next option.
Definition: option.c:209
coap_optlist_t::data
uint8_t * data
the option data
Definition: option.h:412
coap_pdu_t::used_size
size_t used_size
used bytes of storage for token, options and payload
Definition: pdu.h:296
coap_pdu_t::token
uint8_t * token
first byte of token, if any, or options
Definition: pdu.h:298
coap_opt_iterator_t::next_option
coap_opt_t * next_option
pointer to the unparsed next option
Definition: option.h:242
coap_opt_parse
size_t coap_opt_parse(const coap_opt_t *opt, size_t length, coap_option_t *result)
Parses the option pointed to by opt into result.
Definition: option.c:35
coap_opt_iterator_t
Iterator to run through PDU options.
Definition: option.h:237
LL_APPEND
#define LL_APPEND(head, add)
Definition: utlist.h:338
coap_opt_iterator_t::bad
unsigned int bad
iterator object is ok if not set
Definition: option.h:240
coap_option_filter_unset
int coap_option_filter_unset(coap_opt_filter_t filter, uint16_t type)
Clears the corresponding entry for type in filter.
Definition: option.c:528
coap_option_filter_op
static int coap_option_filter_op(coap_opt_filter_t filter, uint16_t type, enum filter_op_t op)
Applies op on filter with respect to type.
Definition: option.c:463
coap_add_option
size_t coap_add_option(coap_pdu_t *pdu, uint16_t type, size_t len, const uint8_t *data)
Adds option of given type to pdu that is passed as first parameter.
Definition: pdu.c:215
coap_option_filter_clear
COAP_STATIC_INLINE void coap_option_filter_clear(coap_opt_filter_t f)
Clears filter f.
Definition: option.h:130
coap_optlist_t::number
uint16_t number
the option number (no delta coding)
Definition: option.h:410
COAP_STATIC_INLINE
#define COAP_STATIC_INLINE
Definition: libcoap.h:38
coap_opt_iterator_t::filtered
unsigned int filtered
denotes whether or not filter is used
Definition: option.h:241
coap_opt_filter_t
uint16_t coap_opt_filter_t[COAP_OPT_FILTER_SIZE]
Fixed-size vector we use for option filtering.
Definition: option.h:119
coap_option_getb
COAP_STATIC_INLINE int coap_option_getb(coap_opt_filter_t filter, uint16_t type)
Gets the corresponding bit for type in filter.
Definition: option.h:217
LL_SORT
#define LL_SORT(list, cmp)
Definition: utlist.h:108
COAP_PAYLOAD_START
#define COAP_PAYLOAD_START
Definition: pdu.h:257
is_long_option
COAP_STATIC_INLINE int is_long_option(uint16_t type)
Returns true iff type denotes an option type larger than 255.
Definition: option.c:438
coap_opt_encode
size_t coap_opt_encode(coap_opt_t *opt, size_t maxlen, uint16_t delta, const uint8_t *val, size_t length)
Encodes option with given delta into opt.
Definition: option.c:398
coap_opt_setheader
size_t coap_opt_setheader(coap_opt_t *opt, size_t maxlen, uint16_t delta, size_t length)
Encodes the given delta and length values into opt.
Definition: option.c:318
coap_opt_value
const uint8_t * coap_opt_value(const coap_opt_t *opt)
Returns a pointer to the value of the given option.
Definition: option.c:275
ADVANCE_OPT
#define ADVANCE_OPT(o, e, step)
Definition: option.c:16
LL_FOREACH_SAFE
#define LL_FOREACH_SAFE(head, el, tmp)
Definition: utlist.h:419
opt_filter::long_opts
uint16_t long_opts[COAP_OPT_FILTER_LONG]
Definition: option.c:432
coap_malloc_type
void * coap_malloc_type(coap_memory_tag_t type, size_t size)
Allocates a chunk of size bytes and returns a pointer to the newly allocated memory.
coap_add_optlist_pdu
int coap_add_optlist_pdu(coap_pdu_t *pdu, coap_optlist_t **options)
The current optlist of optlist_chain is first sorted (as per RFC7272 ordering requirements) and then ...
Definition: option.c:573
opt_filter::short_opts
uint8_t short_opts[COAP_OPT_FILTER_SHORT]
Definition: option.c:433
order_opts
static int order_opts(void *a, void *b)
Definition: option.c:562
coap_log
#define coap_log(level,...)
Logging function.
Definition: coap_debug.h:129
coap_opt_size
size_t coap_opt_size(const coap_opt_t *opt)
Returns the size of the given option, taking into account a possible option jump. ...
Definition: option.c:310
coap_free_type
void coap_free_type(coap_memory_tag_t type, void *p)
Releases the memory that was allocated by coap_malloc_type().
uint8_t
unsigned char uint8_t
Definition: uthash.h:79
coap_new_optlist
coap_optlist_t * coap_new_optlist(uint16_t number, size_t length, const uint8_t *data)
Create a new optlist entry.
Definition: option.c:540
coap_pdu_t::token_length
uint8_t token_length
length of Token
Definition: pdu.h:292
coap_option_iterator_init
coap_opt_iterator_t * coap_option_iterator_init(const coap_pdu_t *pdu, coap_opt_iterator_t *oi, const coap_opt_filter_t filter)
Initializes the given option iterator oi to point to the beginning of the pdu&#39;s option list...
Definition: option.c:110
coap_internal.h
Pulls together all the internal only header files.