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/* net.c -- CoAP network interface
*
* Copyright (C) 2010--2014 Olaf Bergmann <bergmann@tzi.org>
*
* This file is part of the CoAP library libcoap. Please see
* README for terms of use.
*/
#include "coap_config.h"
#include <ctype.h>
#include <stdio.h>
#include <errno.h>
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#elif HAVE_SYS_UNISTD_H
#include <sys/unistd.h>
#endif
#include <sys/types.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef WITH_LWIP
#include <lwip/pbuf.h>
#include <lwip/udp.h>
#include <lwip/timers.h>
#endif
#include "debug.h"
#include "mem.h"
#include "str.h"
#include "async.h"
#include "resource.h"
#include "option.h"
#include "encode.h"
#include "block.h"
#include "net.h"
#if defined(WITH_POSIX)
time_t clock_offset;
static inline coap_queue_t *
coap_malloc_node(void) {
return (coap_queue_t *)coap_malloc_type(COAP_NODE, sizeof(coap_queue_t));
}
static inline void
coap_free_node(coap_queue_t *node) {
coap_free_type(COAP_NODE, node);
}
#endif /* WITH_POSIX */
#ifdef WITH_LWIP
#include <lwip/memp.h>
static void coap_retransmittimer_execute(void *arg);
static void coap_retransmittimer_restart(coap_context_t *ctx);
static inline coap_queue_t *
coap_malloc_node() {
return (coap_queue_t *)memp_malloc(MEMP_COAP_NODE);
}
static inline void
coap_free_node(coap_queue_t *node) {
memp_free(MEMP_COAP_NODE, node);
}
#endif /* WITH_LWIP */
#ifdef WITH_CONTIKI
# ifndef DEBUG
# define DEBUG DEBUG_PRINT
# endif /* DEBUG */
#include "mem.h"
#include "net/ip/uip-debug.h"
clock_time_t clock_offset;
#define UIP_IP_BUF ((struct uip_ip_hdr *)&uip_buf[UIP_LLH_LEN])
#define UIP_UDP_BUF ((struct uip_udp_hdr *)&uip_buf[UIP_LLIPH_LEN])
void coap_resources_init();
unsigned char initialized = 0;
coap_context_t the_coap_context;
PROCESS(coap_retransmit_process, "message retransmit process");
static inline coap_queue_t *
coap_malloc_node() {
return (coap_queue_t *)coap_malloc_type(COAP_NODE, 0);
}
static inline void
coap_free_node(coap_queue_t *node) {
coap_free_type(COAP_NODE, node);
}
#endif /* WITH_CONTIKI */
int print_wellknown(coap_context_t *, unsigned char *, size_t *, size_t, coap_opt_t *);
void coap_handle_failed_notify(coap_context_t *, const coap_address_t *,
const str *);
unsigned int
coap_adjust_basetime(coap_context_t *ctx, coap_tick_t now) {
unsigned int result = 0;
coap_tick_diff_t delta = now - ctx->sendqueue_basetime;
if (ctx->sendqueue) {
/* delta < 0 means that the new time stamp is before the old. */
if (delta <= 0) {
ctx->sendqueue->t -= delta;
} else {
/* This case is more complex: The time must be advanced forward,
* thus possibly leading to timed out elements at the queue's
* start. For every element that has timed out, its relative
* time is set to zero and the result counter is increased. */
coap_queue_t *q = ctx->sendqueue;
coap_tick_t t = 0;
while (q && (t + q->t < (coap_tick_t)delta)) {
t += q->t;
q->t = 0;
result++;
q = q->next;
}
/* finally adjust the first element that has not expired */
if (q) {
q->t = (coap_tick_t)delta - t;
}
}
}
/* adjust basetime */
ctx->sendqueue_basetime += delta;
return result;
}
int
coap_insert_node(coap_queue_t **queue, coap_queue_t *node) {
coap_queue_t *p, *q;
if ( !queue || !node )
return 0;
/* set queue head if empty */
if ( !*queue ) {
*queue = node;
return 1;
}
/* replace queue head if PDU's time is less than head's time */
q = *queue;
if (node->t < q->t) {
node->next = q;
*queue = node;
q->t -= node->t; /* make q->t relative to node->t */
return 1;
}
/* search for right place to insert */
do {
node->t -= q->t; /* make node-> relative to q->t */
p = q;
q = q->next;
} while (q && q->t <= node->t);
/* insert new item */
if (q) {
q->t -= node->t; /* make q->t relative to node->t */
}
node->next = q;
p->next = node;
return 1;
}
int
coap_delete_node(coap_queue_t *node) {
if ( !node )
return 0;
coap_delete_pdu(node->pdu);
coap_free_node(node);
return 1;
}
void
coap_delete_all(coap_queue_t *queue) {
if ( !queue )
return;
coap_delete_all( queue->next );
coap_delete_node( queue );
}
coap_queue_t *
coap_new_node(void) {
coap_queue_t *node;
node = coap_malloc_node();
if ( ! node ) {
#ifndef NDEBUG
coap_log(LOG_WARNING, "coap_new_node: malloc\n");
#endif
return NULL;
}
memset(node, 0, sizeof(*node));
return node;
}
coap_queue_t *
coap_peek_next( coap_context_t *context ) {
if ( !context || !context->sendqueue )
return NULL;
return context->sendqueue;
}
coap_queue_t *
coap_pop_next( coap_context_t *context ) {
coap_queue_t *next;
if ( !context || !context->sendqueue )
return NULL;
next = context->sendqueue;
context->sendqueue = context->sendqueue->next;
if (context->sendqueue) {
context->sendqueue->t += next->t;
}
next->next = NULL;
return next;
}
#ifdef COAP_DEFAULT_WKC_HASHKEY
/** Checks if @p Key is equal to the pre-defined hash key for.well-known/core. */
#define is_wkc(Key) \
(memcmp((Key), COAP_DEFAULT_WKC_HASHKEY, sizeof(coap_key_t)) == 0)
#else
/* Implements a singleton to store a hash key for the .wellknown/core
* resources. */
int
is_wkc(coap_key_t k) {
static coap_key_t wkc;
static unsigned char _initialized = 0;
if (!_initialized) {
_initialized = coap_hash_path((unsigned char *)COAP_DEFAULT_URI_WELLKNOWN,
sizeof(COAP_DEFAULT_URI_WELLKNOWN) - 1, wkc);
}
return memcmp(k, wkc, sizeof(coap_key_t)) == 0;
}
#endif
coap_context_t *
coap_new_context(
const coap_address_t *listen_addr) {
#ifndef WITH_CONTIKI
coap_context_t *c = coap_malloc_type(COAP_CONTEXT, sizeof( coap_context_t ) );
#endif /* not WITH_CONTIKI */
#ifdef WITH_CONTIKI
coap_context_t *c;
if (initialized)
return NULL;
#endif /* WITH_CONTIKI */
if (!listen_addr) {
coap_log(LOG_EMERG, "no listen address specified\n");
return NULL;
}
coap_clock_init();
#ifdef WITH_LWIP
prng_init(LWIP_RAND());
#endif /* WITH_LWIP */
#ifdef WITH_CONTIKI
prng_init((ptrdiff_t)listen_addr ^ clock_offset);
#endif /* WITH_LWIP */
#ifdef WITH_POSIX
prng_init((unsigned long)listen_addr ^ clock_offset);
#endif /* WITH_POSIX */
#ifndef WITH_CONTIKI
if (!c) {
#ifndef NDEBUG
coap_log(LOG_EMERG, "coap_init: malloc:\n");
#endif
return NULL;
}
#endif /* not WITH_CONTIKI */
#ifdef WITH_CONTIKI
coap_resources_init();
coap_memory_init();
c = &the_coap_context;
initialized = 1;
#endif /* WITH_CONTIKI */
memset(c, 0, sizeof( coap_context_t ) );
/* initialize message id */
prng((unsigned char *)&c->message_id, sizeof(unsigned short));
/* register the critical options that we know */
coap_register_option(c, COAP_OPTION_IF_MATCH);
coap_register_option(c, COAP_OPTION_URI_HOST);
coap_register_option(c, COAP_OPTION_IF_NONE_MATCH);
coap_register_option(c, COAP_OPTION_URI_PORT);
coap_register_option(c, COAP_OPTION_URI_PATH);
coap_register_option(c, COAP_OPTION_URI_QUERY);
coap_register_option(c, COAP_OPTION_ACCEPT);
coap_register_option(c, COAP_OPTION_PROXY_URI);
coap_register_option(c, COAP_OPTION_PROXY_SCHEME);
coap_register_option(c, COAP_OPTION_BLOCK2);
coap_register_option(c, COAP_OPTION_BLOCK1);
c->endpoint = coap_new_endpoint(listen_addr, COAP_ENDPOINT_NOSEC);
#ifdef WITH_LWIP
c->endpoint->context = c;
#endif
if (c->endpoint == NULL) {
goto onerror;
}
#ifdef WITH_POSIX
c->sockfd = c->endpoint->handle.fd;
#endif /* WITH_POSIX */
#if defined(WITH_POSIX) || defined(WITH_CONTIKI)
c->network_send = coap_network_send;
c->network_read = coap_network_read;
#endif /* WITH_POSIX or WITH_CONTIKI */
#ifdef WITH_CONTIKI
process_start(&coap_retransmit_process, (char *)c);
PROCESS_CONTEXT_BEGIN(&coap_retransmit_process);
#ifndef WITHOUT_OBSERVE
etimer_set(&c->notify_timer, COAP_RESOURCE_CHECK_TIME * COAP_TICKS_PER_SECOND);
#endif /* WITHOUT_OBSERVE */
/* the retransmit timer must be initialized to some large value */
etimer_set(&the_coap_context.retransmit_timer, 0xFFFF);
PROCESS_CONTEXT_END(&coap_retransmit_process);
#endif /* WITH_CONTIKI */
return c;
onerror:
coap_free(c);
return NULL;
}
void
coap_free_context(coap_context_t *context) {
#if defined(WITH_POSIX) || defined(WITH_LWIP)
coap_resource_t *res;
#ifndef COAP_RESOURCES_NOHASH
coap_resource_t *rtmp;
#endif
#endif /* WITH_POSIX || WITH_LWIP */
if (!context)
return;
coap_delete_all(context->sendqueue);
#ifdef WITH_LWIP
context->sendqueue = NULL;
coap_retransmittimer_restart(context);
#endif
#if defined(WITH_POSIX) || defined(WITH_LWIP)
#ifdef COAP_RESOURCES_NOHASH
LL_FOREACH(context->resources, res) {
#else
HASH_ITER(hh, context->resources, res, rtmp) {
#endif
coap_delete_resource(context, res->key);
}
#endif /* WITH_POSIX || WITH_LWIP */
coap_free_endpoint(context->endpoint);
#ifndef WITH_CONTIKI
coap_free_type(COAP_CONTEXT, context);
#endif/* not WITH_CONTIKI */
#ifdef WITH_CONTIKI
memset(&the_coap_context, 0, sizeof(coap_context_t));
initialized = 0;
#endif /* WITH_CONTIKI */
}
int
coap_option_check_critical(coap_context_t *ctx,
coap_pdu_t *pdu,
coap_opt_filter_t unknown) {
coap_opt_iterator_t opt_iter;
int ok = 1;
coap_option_iterator_init(pdu, &opt_iter, COAP_OPT_ALL);
while (coap_option_next(&opt_iter)) {
/* The following condition makes use of the fact that
* coap_option_getb() returns -1 if type exceeds the bit-vector
* filter. As the vector is supposed to be large enough to hold
* the largest known option, we know that everything beyond is
* bad.
*/
if (opt_iter.type & 0x01 &&
coap_option_getb(ctx->known_options, opt_iter.type) < 1) {
debug("unknown critical option %d\n", opt_iter.type);
ok = 0;
/* When opt_iter.type is beyond our known option range,
* coap_option_setb() will return -1 and we are safe to leave
* this loop. */
if (coap_option_setb(unknown, opt_iter.type) == -1)
break;
}
}
return ok;
}
void
coap_transaction_id(const coap_address_t *peer, const coap_pdu_t *pdu,
coap_tid_t *id) {
coap_key_t h;
memset(h, 0, sizeof(coap_key_t));
/* Compare the transport address. */
#ifdef WITH_POSIX
switch (peer->addr.sa.sa_family) {
case AF_INET:
coap_hash((const unsigned char *)&peer->addr.sin.sin_port,
sizeof(peer->addr.sin.sin_port), h);
coap_hash((const unsigned char *)&peer->addr.sin.sin_addr,
sizeof(peer->addr.sin.sin_addr), h);
break;
case AF_INET6:
coap_hash((const unsigned char *)&peer->addr.sin6.sin6_port,
sizeof(peer->addr.sin6.sin6_port), h);
coap_hash((const unsigned char *)&peer->addr.sin6.sin6_addr,
sizeof(peer->addr.sin6.sin6_addr), h);
break;
default:
return;
}
#endif
#if defined(WITH_LWIP) || defined(WITH_CONTIKI)
/* FIXME: with lwip, we can do better */
coap_hash((const unsigned char *)&peer->port, sizeof(peer->port), h);
coap_hash((const unsigned char *)&peer->addr, sizeof(peer->addr), h);
#endif /* WITH_LWIP || WITH_CONTIKI */
coap_hash((const unsigned char *)&pdu->hdr->id, sizeof(unsigned short), h);
*id = ((h[0] << 8) | h[1]) ^ ((h[2] << 8) | h[3]);
}
coap_tid_t
coap_send_ack(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *request) {
coap_pdu_t *response;
coap_tid_t result = COAP_INVALID_TID;
if (request && request->hdr->type == COAP_MESSAGE_CON) {
response = coap_pdu_init(COAP_MESSAGE_ACK, 0, request->hdr->id,
sizeof(coap_pdu_t));
if (response) {
result = coap_send(context, local_interface, dst, response);
coap_delete_pdu(response);
}
}
return result;
}
#if defined(WITH_POSIX) || defined(WITH_CONTIKI)
/* releases space allocated by PDU if free_pdu is set */
coap_tid_t
coap_send_impl(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *pdu) {
ssize_t bytes_written;
coap_tid_t id = COAP_INVALID_TID;
if ( !context || !dst || !pdu )
return id;
bytes_written = context->network_send(context, local_interface, dst,
(unsigned char *)pdu->hdr, pdu->length);
if (bytes_written >= 0) {
coap_transaction_id(dst, pdu, &id);
} else {
coap_log(LOG_CRIT, "coap_send_impl: %s\n", strerror(errno));
}
return id;
}
#endif /* WITH_POSIX */
#ifdef WITH_LWIP
coap_tid_t
coap_send_impl(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *pdu) {
coap_tid_t id = COAP_INVALID_TID;
uint8_t err;
char *data_backup;
if ( !context || !dst || !pdu )
{
return id;
}
data_backup = pdu->data;
/* FIXME: we can't check this here with the existing infrastructure, but we
* should actually check that the pdu is not held by anyone but us. the
* respective pbuf is already exclusively owned by the pdu. */
pbuf_realloc(pdu->pbuf, pdu->length);
coap_transaction_id(dst, pdu, &id);
udp_sendto(context->endpoint->pcb, pdu->pbuf,
&dst->addr, dst->port);
return id;
}
#endif /* WITH_LWIP */
coap_tid_t
coap_send(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *pdu) {
return coap_send_impl(context, local_interface, dst, pdu);
}
coap_tid_t
coap_send_error(coap_context_t *context,
coap_pdu_t *request,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
unsigned char code,
coap_opt_filter_t opts) {
coap_pdu_t *response;
coap_tid_t result = COAP_INVALID_TID;
assert(request);
assert(dst);
response = coap_new_error_response(request, code, opts);
if (response) {
result = coap_send(context, local_interface, dst, response);
coap_delete_pdu(response);
}
return result;
}
coap_tid_t
coap_send_message_type(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *request,
unsigned char type) {
coap_pdu_t *response;
coap_tid_t result = COAP_INVALID_TID;
if (request) {
response = coap_pdu_init(type, 0, request->hdr->id, sizeof(coap_pdu_t));
if (response) {
result = coap_send(context, local_interface, dst, response);
coap_delete_pdu(response);
}
}
return result;
}
coap_tid_t
coap_send_confirmed(coap_context_t *context,
const coap_endpoint_t *local_interface,
const coap_address_t *dst,
coap_pdu_t *pdu) {
coap_queue_t *node;
coap_tick_t now;
int r;
node = coap_new_node();
if (!node) {
debug("coap_send_confirmed: insufficient memory\n");
return COAP_INVALID_TID;
}
node->id = coap_send_impl(context, local_interface, dst, pdu);
if (COAP_INVALID_TID == node->id) {
debug("coap_send_confirmed: error sending pdu\n");
coap_free_node(node);
return COAP_INVALID_TID;
}
prng((unsigned char *)&r,sizeof(r));
/* add randomized RESPONSE_TIMEOUT to determine retransmission timeout */
node->timeout = COAP_DEFAULT_RESPONSE_TIMEOUT * COAP_TICKS_PER_SECOND +
(COAP_DEFAULT_RESPONSE_TIMEOUT >> 1) *
((COAP_TICKS_PER_SECOND * (r & 0xFF)) >> 8);
node->local_if = *local_interface;
memcpy(&node->remote, dst, sizeof(coap_address_t));
node->pdu = pdu;
/* Set timer for pdu retransmission. If this is the first element in
* the retransmission queue, the base time is set to the current
* time and the retransmission time is node->timeout. If there is
* already an entry in the sendqueue, we must check if this node is
* to be retransmitted earlier. Therefore, node->timeout is first
* normalized to the base time and then inserted into the queue with
* an adjusted relative time.
*/
coap_ticks(&now);
if (context->sendqueue == NULL) {
node->t = node->timeout;
context->sendqueue_basetime = now;
} else {
/* make node->t relative to context->sendqueue_basetime */
node->t = (now - context->sendqueue_basetime) + node->timeout;
}
coap_insert_node(&context->sendqueue, node);
#ifdef WITH_LWIP
if (node == context->sendqueue) /* don't bother with timer stuff if there are earlier retransmits */
coap_retransmittimer_restart(context);
#endif
#ifdef WITH_CONTIKI
{ /* (re-)initialize retransmission timer */
coap_queue_t *nextpdu;
nextpdu = coap_peek_next(context);
assert(nextpdu); /* we have just inserted a node */
/* must set timer within the context of the retransmit process */
PROCESS_CONTEXT_BEGIN(&coap_retransmit_process);
etimer_set(&context->retransmit_timer, nextpdu->t);
PROCESS_CONTEXT_END(&coap_retransmit_process);
}
#endif /* WITH_CONTIKI */
return node->id;
}
coap_tid_t
coap_retransmit(coap_context_t *context, coap_queue_t *node) {
if (!context || !node)
return COAP_INVALID_TID;
/* re-initialize timeout when maximum number of retransmissions are not reached yet */
if (node->retransmit_cnt < COAP_DEFAULT_MAX_RETRANSMIT) {
node->retransmit_cnt++;
node->t = node->timeout << node->retransmit_cnt;
coap_insert_node(&context->sendqueue, node);
#ifdef WITH_LWIP
if (node == context->sendqueue) /* don't bother with timer stuff if there are earlier retransmits */
coap_retransmittimer_restart(context);
#endif
debug("** retransmission #%d of transaction %d\n",
node->retransmit_cnt, ntohs(node->pdu->hdr->id));
node->id = coap_send_impl(context, &node->local_if,
&node->remote, node->pdu);
return node->id;
}
/* no more retransmissions, remove node from system */
#ifndef WITH_CONTIKI
debug("** removed transaction %d\n", ntohs(node->id));
#endif
#ifndef WITHOUT_OBSERVE
/* Check if subscriptions exist that should be canceled after
COAP_MAX_NOTIFY_FAILURES */
if (node->pdu->hdr->code >= 64) {
str token = { 0, NULL };
token.length = node->pdu->hdr->token_length;
token.s = node->pdu->hdr->token;
coap_handle_failed_notify(context, &node->remote, &token);
}
#endif /* WITHOUT_OBSERVE */
/* And finally delete the node */
coap_delete_node( node );
return COAP_INVALID_TID;
}
/**
* Checks if @p opt fits into the message that ends with @p maxpos.
* This function returns @c 1 on success, or @c 0 if the option @p opt
* would exceed @p maxpos.
*/
static inline int
check_opt_size(coap_opt_t *opt, unsigned char *maxpos) {
if (opt && opt < maxpos) {
if (((*opt & 0x0f) < 0x0f) || (opt + 1 < maxpos))
return opt + COAP_OPT_SIZE(opt) < maxpos;
}
return 0;
}
void coap_dispatch(coap_context_t *context, coap_queue_t *rcvd);
int
coap_read( coap_context_t *ctx ) {
ssize_t bytes_read = -1;
coap_packet_t *packet;
coap_address_t src;
int result = -1; /* the value to be returned */
coap_address_init(&src);
#if defined(WITH_POSIX) || defined(WITH_CONTIKI)
bytes_read = ctx->network_read(ctx->endpoint, &packet);
#endif /* WITH_POSIX or WITH_CONTIKI */
if ( bytes_read < 0 ) {
warn("coap_read: recvfrom");
} else {
#if defined(WITH_POSIX) || defined(WITH_CONTIKI)
result = coap_handle_message(ctx, packet);
#endif /* WITH_POSIX or WITH_CONTIKI */
}
coap_free_packet(packet);
return result;
}
int
coap_handle_message(coap_context_t *ctx,
coap_packet_t *packet) {
/* const coap_address_t *remote, */
/* unsigned char *msg, size_t msg_len) { */
unsigned char *msg;
size_t msg_len;
coap_queue_t *node;
/* the negated result code */
enum result_t { RESULT_OK, RESULT_ERR_EARLY, RESULT_ERR };
int result = RESULT_ERR_EARLY;
coap_packet_get_memmapped(packet, &msg, &msg_len);
if (msg_len < sizeof(coap_hdr_t)) {
debug("coap_handle_message: discarded invalid frame\n" );
goto error_early;
}
/* check version identifier */
if (((*msg >> 6) & 0x03) != COAP_DEFAULT_VERSION) {
debug("coap_handle_message: unknown protocol version %d\n", (*msg >> 6) & 0x03);
goto error_early;
}
node = coap_new_node();
if (!node) {
goto error_early;
}
/* from this point, the result code indicates that */
result = RESULT_ERR;
#ifdef WITH_LWIP
node->pdu = coap_pdu_from_pbuf(coap_packet_extract_pbuf(packet));
#else
node->pdu = coap_pdu_init(0, 0, 0, msg_len);
#endif
if (!node->pdu) {
goto error;
}
if (!coap_pdu_parse(msg, msg_len, node->pdu)) {
warn("discard malformed PDU\n");
goto error;
}
coap_ticks(&node->t);
coap_packet_populate_endpoint(packet, &node->local_if);
coap_packet_copy_source(packet, &node->remote);
/* and add new node to receive queue */
coap_transaction_id(&node->remote, node->pdu, &node->id);
#ifndef NDEBUG
if (LOG_DEBUG <= coap_get_log_level()) {
#ifndef INET6_ADDRSTRLEN
#define INET6_ADDRSTRLEN 40
#endif
/** @FIXME get debug to work again **
unsigned char addr[INET6_ADDRSTRLEN+8], localaddr[INET6_ADDRSTRLEN+8];
if (coap_print_addr(remote, addr, INET6_ADDRSTRLEN+8) &&
coap_print_addr(&packet->dst, localaddr, INET6_ADDRSTRLEN+8) )
debug("** received %d bytes from %s on interface %s:\n",
(int)msg_len, addr, localaddr);
*/
coap_show_pdu(node->pdu);
}
#endif
coap_dispatch(ctx, node);
return -RESULT_OK;
error:
/* FIXME: send back RST? */
coap_delete_node(node);
return -result;
error_early:
return -result;
}
int
coap_remove_from_queue(coap_queue_t **queue, coap_tid_t id, coap_queue_t **node) {
coap_queue_t *p, *q;
if ( !queue || !*queue)
return 0;
/* replace queue head if PDU's time is less than head's time */
if ( id == (*queue)->id ) { /* found transaction */
*node = *queue;
*queue = (*queue)->next;
if (*queue) { /* adjust relative time of new queue head */
(*queue)->t += (*node)->t;
}
(*node)->next = NULL;
/* coap_delete_node( q ); */
debug("*** removed transaction %u\n", id);
return 1;
}
/* search transaction to remove (only first occurence will be removed) */
q = *queue;
do {
p = q;
q = q->next;
} while ( q && id != q->id );
if ( q ) { /* found transaction */
p->next = q->next;
if (p->next) { /* must update relative time of p->next */
p->next->t += q->t;
}
q->next = NULL;
*node = q;
/* coap_delete_node( q ); */
debug("*** removed transaction %u\n", id);
return 1;
}
return 0;
}
static inline int
token_match(const unsigned char *a, size_t alen,
const unsigned char *b, size_t blen) {
return alen == blen && (alen == 0 || memcmp(a, b, alen) == 0);
}
void
coap_cancel_all_messages(coap_context_t *context, const coap_address_t *dst,
const unsigned char *token, size_t token_length) {
/* cancel all messages in sendqueue that are for dst
* and use the specified token */
coap_queue_t *p, *q;
while (context->sendqueue &&
coap_address_equals(dst, &context->sendqueue->remote) &&
token_match(token, token_length,
context->sendqueue->pdu->hdr->token,
context->sendqueue->pdu->hdr->token_length)) {
q = context->sendqueue;
context->sendqueue = q->next;
debug("**** removed transaction %d\n", ntohs(q->pdu->hdr->id));
coap_delete_node(q);
}
if (!context->sendqueue)
return;
p = context->sendqueue;
q = p->next;
/* when q is not NULL, it does not match (dst, token), so we can skip it */
while (q) {
if (coap_address_equals(dst, &q->remote) &&
token_match(token, token_length,
q->pdu->hdr->token, q->pdu->hdr->token_length)) {
p->next = q->next;
debug("**** removed transaction %d\n", ntohs(q->pdu->hdr->id));
coap_delete_node(q);
q = p->next;
} else {
p = q;
q = q->next;
}
}
}
coap_queue_t *
coap_find_transaction(coap_queue_t *queue, coap_tid_t id) {
while (queue && queue->id != id)
queue = queue->next;
return queue;
}
coap_pdu_t *
coap_new_error_response(coap_pdu_t *request, unsigned char code,
coap_opt_filter_t opts) {
coap_opt_iterator_t opt_iter;
coap_pdu_t *response;
size_t size = sizeof(coap_hdr_t) + request->hdr->token_length;
int type;
coap_opt_t *option;
unsigned short opt_type = 0; /* used for calculating delta-storage */
#if COAP_ERROR_PHRASE_LENGTH > 0
char *phrase = coap_response_phrase(code);
/* Need some more space for the error phrase and payload start marker */
if (phrase)
size += strlen(phrase) + 1;
#endif
assert(request);
/* cannot send ACK if original request was not confirmable */
type = request->hdr->type == COAP_MESSAGE_CON
? COAP_MESSAGE_ACK
: COAP_MESSAGE_NON;
/* Estimate how much space we need for options to copy from
* request. We always need the Token, for 4.02 the unknown critical
* options must be included as well. */
coap_option_clrb(opts, COAP_OPTION_CONTENT_TYPE); /* we do not want this */
coap_option_iterator_init(request, &opt_iter, opts);
/* Add size of each unknown critical option. As known critical
options as well as elective options are not copied, the delta
value might grow.
*/
while((option = coap_option_next(&opt_iter))) {
unsigned short delta = opt_iter.type - opt_type;
/* calculate space required to encode (opt_iter.type - opt_type) */
if (delta < 13) {
size++;
} else if (delta < 269) {
size += 2;
} else {
size += 3;
}
/* add coap_opt_length(option) and the number of additional bytes
* required to encode the option length */
size += coap_opt_length(option);
switch (*option & 0x0f) {
case 0x0e:
size++;
/* fall through */
case 0x0d:
size++;
break;
default:
;
}
opt_type = opt_iter.type;
}
/* Now create the response and fill with options and payload data. */
response = coap_pdu_init(type, code, request->hdr->id, size);
if (response) {
/* copy token */
if (!coap_add_token(response, request->hdr->token_length,
request->hdr->token)) {
debug("cannot add token to error response\n");
coap_delete_pdu(response);
return NULL;
}
/* copy all options */
coap_option_iterator_init(request, &opt_iter, opts);
while((option = coap_option_next(&opt_iter)))
coap_add_option(response, opt_iter.type,
COAP_OPT_LENGTH(option),
COAP_OPT_VALUE(option));
#if COAP_ERROR_PHRASE_LENGTH > 0
/* note that diagnostic messages do not need a Content-Format option. */
if (phrase)
coap_add_data(response, strlen(phrase), (unsigned char *)phrase);
#endif
}
return response;
}
/**
* Quick hack to determine the size of the resource description for
* .well-known/core.
*/
static inline size_t
get_wkc_len(coap_context_t *context, coap_opt_t *query_filter) {
unsigned char buf[1];
size_t len = 0;
if (print_wellknown(context, buf, &len, UINT_MAX, query_filter)
& COAP_PRINT_STATUS_ERROR) {
warn("cannot determine length of /.well-known/core\n");
return 0;
}
debug("get_wkc_len: print_wellknown() returned %zu\n", len);
return len;
}
#define SZX_TO_BYTES(SZX) ((size_t)(1 << ((SZX) + 4)))
coap_pdu_t *
wellknown_response(coap_context_t *context, coap_pdu_t *request) {
coap_pdu_t *resp;
coap_opt_iterator_t opt_iter;
size_t len, wkc_len;
unsigned char buf[2];
int result = 0;
int need_block2 = 0; /* set to 1 if Block2 option is required */
coap_block_t block;
coap_opt_t *query_filter;
size_t offset = 0;
resp = coap_pdu_init(request->hdr->type == COAP_MESSAGE_CON
? COAP_MESSAGE_ACK
: COAP_MESSAGE_NON,
COAP_RESPONSE_CODE(205),
request->hdr->id, COAP_MAX_PDU_SIZE);
if (!resp) {
debug("wellknown_response: cannot create PDU\n");
return NULL;
}
if (!coap_add_token(resp, request->hdr->token_length, request->hdr->token)) {
debug("wellknown_response: cannot add token\n");
goto error;
}
query_filter = coap_check_option(request, COAP_OPTION_URI_QUERY, &opt_iter);
wkc_len = get_wkc_len(context, query_filter);
/* check whether the request contains the Block2 option */
if (coap_get_block(request, COAP_OPTION_BLOCK2, &block)) {
debug("create block\n");
offset = block.num << (block.szx + 4);
if (block.szx > 6) { /* invalid, MUST lead to 4.00 Bad Request */
resp->hdr->code = COAP_RESPONSE_CODE(400);
return resp;
} else if (block.szx > COAP_MAX_BLOCK_SZX) {
block.szx = COAP_MAX_BLOCK_SZX;
block.num = offset >> (block.szx + 4);
}
need_block2 = 1;
}
/* Check if there is sufficient space to add Content-Format option
* and data. We do this before adding the Content-Format option to
* avoid sending error responses with that option but no actual
* content. */
if (resp->max_size <= (size_t)resp->length + 3) {
debug("wellknown_response: insufficient storage space\n");
goto error;
}
/* Add Content-Format. As we have checked for available storage,
* nothing should go wrong here. */
assert(coap_encode_var_bytes(buf,
COAP_MEDIATYPE_APPLICATION_LINK_FORMAT) == 1);
coap_add_option(resp, COAP_OPTION_CONTENT_FORMAT,
coap_encode_var_bytes(buf,
COAP_MEDIATYPE_APPLICATION_LINK_FORMAT), buf);
/* check if Block2 option is required even if not requested */
if (!need_block2 && (resp->max_size - (size_t)resp->length < wkc_len)) {
assert(resp->length <= resp->max_size);
const size_t payloadlen = resp->max_size - resp->length;
/* yes, need block-wise transfer */
block.num = 0;
block.m = 0; /* the M bit is set by coap_write_block_opt() */
block.szx = COAP_MAX_BLOCK_SZX;
while (payloadlen < SZX_TO_BYTES(block.szx)) {
if (block.szx == 0) {
debug("wellknown_response: message to small even for szx == 0\n");
goto error;
} else {
block.szx--;
}
}
need_block2 = 1;
}
/* write Block2 option if necessary */
if (need_block2) {
if (coap_write_block_opt(&block, COAP_OPTION_BLOCK2, resp, wkc_len) < 0) {
debug("wellknown_response: cannot add Block2 option\n");
goto error;
}
}
/* Manually set payload of response to let print_wellknown() write,
* into our buffer without copying data. */
resp->data = (unsigned char *)resp->hdr + resp->length;
*resp->data = COAP_PAYLOAD_START;
resp->data++;
resp->length++;
len = need_block2 ? SZX_TO_BYTES(block.szx) : resp->max_size - resp->length;
result = print_wellknown(context, resp->data, &len, offset, query_filter);
if ((result & COAP_PRINT_STATUS_ERROR) != 0) {
debug("print_wellknown failed\n");
goto error;
}
resp->length += COAP_PRINT_OUTPUT_LENGTH(result);
return resp;
error:
/* set error code 5.03 and remove all options and data from response */
resp->hdr->code = COAP_RESPONSE_CODE(503);
resp->length = sizeof(coap_hdr_t) + resp->hdr->token_length;
return resp;
}
/**
* This function cancels outstanding messages for the remote peer and
* token specified in @p sent. Any observation relationship for
* sent->remote and the token are removed. Calling this function is
* required when receiving an RST message (usually in response to a
* notification) or a GET request with the Observe option set to 1.
*
* This function returns @c 0 when the token is unknown with this
* peer, or a value greater than zero otherwise.
*/
static int
coap_cancel(coap_context_t *context, const coap_queue_t *sent) {
#ifndef WITHOUT_OBSERVE
#ifdef WITH_CONTIKI
coap_iterator_t resource_iter;
coap_resource_t *r;
#else
coap_resource_t *r;
#ifndef COAP_RESOURCES_NOHASH
coap_resource_t *tmp;
#endif
#endif
str token = { 0, NULL };
int num_cancelled = 0; /* the number of observers cancelled */
/* remove observer for this resource, if any
* get token from sent and try to find a matching resource. Uh!
*/
COAP_SET_STR(&token, sent->pdu->hdr->token_length, sent->pdu->hdr->token);
#ifdef WITH_CONTIKI
/* traverse resources and delete matching observers for each resource */
if (coap_resource_iterator_init(context->resources, &resource_iter) != NULL) {
while ((r = coap_resource_next(&resource_iter))) {
num_cancelled += coap_delete_observer(r, &sent->remote, &token);
coap_cancel_all_messages(context, &sent->remote, token.s, token.length);
}
}
#else
#ifdef COAP_RESOURCES_NOHASH
LL_FOREACH(context->resources, r) {
#else /* COAP_RESOURCES_NOHASH */
HASH_ITER(hh, context->resources, r, tmp) {
#endif
num_cancelled += coap_delete_observer(r, &sent->remote, &token);
coap_cancel_all_messages(context, &sent->remote, token.s, token.length);
}
#endif /* not WITH_CONTIKI */
return num_cancelled;
#else /* WITOUT_OBSERVE */
return 0;
#endif /* WITOUT_OBSERVE */
}
#define WANT_WKC(Pdu,Key) \
(((Pdu)->hdr->code == COAP_REQUEST_GET) && is_wkc(Key))
void
handle_request(coap_context_t *context, coap_queue_t *node) {
coap_method_handler_t h = NULL;
coap_pdu_t *response = NULL;
coap_opt_filter_t opt_filter;
coap_resource_t *resource;
coap_key_t key;
coap_option_filter_clear(opt_filter);
/* try to find the resource from the request URI */
coap_hash_request_uri(node->pdu, key);
resource = coap_get_resource_from_key(context, key);
if (!resource) {
/* The resource was not found. Check if the request URI happens to
* be the well-known URI. In that case, we generate a default
* response, otherwise, we return 4.04 */
switch(node->pdu->hdr->code) {
case COAP_REQUEST_GET:
if (is_wkc(key)) { /* GET request for .well-known/core */
info("create default response for %s\n", COAP_DEFAULT_URI_WELLKNOWN);
response = wellknown_response(context, node->pdu);
} else { /* GET request for any another resource, return 4.04 */
debug("GET for unknown resource 0x%02x%02x%02x%02x, return 4.04\n",
key[0], key[1], key[2], key[3]);
response =
coap_new_error_response(node->pdu, COAP_RESPONSE_CODE(404),
opt_filter);
}
break;
default: /* any other request type */
debug("unhandled request for unknown resource 0x%02x%02x%02x%02x\r\n",
key[0], key[1], key[2], key[3]);
if (!coap_mcast_interface(&node->local_if))
response = coap_new_error_response(node->pdu, COAP_RESPONSE_CODE(405),
opt_filter);
}
if (response && coap_send(context, &node->local_if,
&node->remote, response) == COAP_INVALID_TID) {
warn("cannot send response for transaction %u\n", node->id);
}
coap_delete_pdu(response);
return;
}
/* the resource was found, check if there is a registered handler */
if ((size_t)node->pdu->hdr->code - 1 <
sizeof(resource->handler)/sizeof(coap_method_handler_t))
h = resource->handler[node->pdu->hdr->code - 1];
if (h) {
debug("call custom handler for resource 0x%02x%02x%02x%02x\n",
key[0], key[1], key[2], key[3]);
response = coap_pdu_init(node->pdu->hdr->type == COAP_MESSAGE_CON
? COAP_MESSAGE_ACK
: COAP_MESSAGE_NON,
0, node->pdu->hdr->id, COAP_MAX_PDU_SIZE);
/* Implementation detail: coap_add_token() immediately returns 0
if response == NULL */
if (coap_add_token(response, node->pdu->hdr->token_length,
node->pdu->hdr->token)) {
str token = { node->pdu->hdr->token_length, node->pdu->hdr->token };
coap_opt_iterator_t opt_iter;
coap_opt_t *observe = NULL;
int observe_action = COAP_OBSERVE_CANCEL;
/* check for Observe option */
if (resource->observable) {
observe = coap_check_option(node->pdu, COAP_OPTION_OBSERVE, &opt_iter);
if (observe) {
observe_action =
coap_decode_var_bytes(coap_opt_value(observe),
coap_opt_length(observe));
if ((observe_action & COAP_OBSERVE_CANCEL) == 0) {
coap_subscription_t *subscription;
coap_log(LOG_DEBUG, "create new subscription\n");
subscription = coap_add_observer(resource, &node->local_if,
&node->remote, &token);
if (subscription) {
subscription->non = node->pdu->hdr->type == COAP_MESSAGE_NON;
coap_touch_observer(context, &node->remote, &token);
}
}
}
}
h(context, resource, &node->local_if, &node->remote,
node->pdu, &token, response);
if (observe && ((COAP_RESPONSE_CLASS(response->hdr->code) > 2)
|| ((observe_action & COAP_OBSERVE_CANCEL) != 0))) {
coap_log(LOG_DEBUG, "removed observer");
coap_delete_observer(resource, &node->remote, &token);
}
/* If original request contained a token, and the registered
* application handler made no changes to the response, then
* this is an empty ACK with a token, which is a malformed
* PDU */
if ((response->hdr->type == COAP_MESSAGE_ACK)
&& (response->hdr->code == 0)) {
/* Remove token from otherwise-empty acknowledgment PDU */
response->hdr->token_length = 0;
response->length = sizeof(coap_hdr_t);
}
if (response->hdr->type != COAP_MESSAGE_NON ||
(response->hdr->code >= 64
&& !coap_mcast_interface(&node->local_if))) {
if (coap_send(context, &node->local_if,
&node->remote, response) == COAP_INVALID_TID) {
debug("cannot send response for message %d\n", node->pdu->hdr->id);
}
}
coap_delete_pdu(response);
} else {
warn("cannot generate response\r\n");
}
} else {
if (WANT_WKC(node->pdu, key)) {
debug("create default response for %s\n", COAP_DEFAULT_URI_WELLKNOWN);
response = wellknown_response(context, node->pdu);
debug("have wellknown response %p\n", (void *)response);
} else
response = coap_new_error_response(node->pdu, COAP_RESPONSE_CODE(405),
opt_filter);
if (!response || (coap_send(context, &node->local_if, &node->remote,
response) == COAP_INVALID_TID)) {
debug("cannot send response for transaction %u\n", node->id);
}
coap_delete_pdu(response);
}
}
static inline void
handle_response(coap_context_t *context,
coap_queue_t *sent, coap_queue_t *rcvd) {
coap_send_ack(context, &rcvd->local_if, &rcvd->remote, rcvd->pdu);
/* In a lossy context, the ACK of a separate response may have
* been lost, so we need to stop retransmitting requests with the
* same token.
*/
coap_cancel_all_messages(context, &rcvd->remote,
rcvd->pdu->hdr->token,
rcvd->pdu->hdr->token_length);
/* Call application-specific reponse handler when available. */
if (context->response_handler) {
context->response_handler(context, &rcvd->local_if,
&rcvd->remote, sent ? sent->pdu : NULL,
rcvd->pdu, rcvd->id);
}
}
static inline int
#ifdef __GNUC__
handle_locally(coap_context_t *context __attribute__ ((unused)),
coap_queue_t *node __attribute__ ((unused))) {
#else /* not a GCC */
handle_locally(coap_context_t *context, coap_queue_t *node) {
#endif /* GCC */
/* this function can be used to check if node->pdu is really for us */
return 1;
}
void
coap_dispatch(coap_context_t *context, coap_queue_t *rcvd) {
coap_queue_t *sent = NULL;
coap_pdu_t *response;
coap_opt_filter_t opt_filter;
if (!context)
return;
memset(opt_filter, 0, sizeof(coap_opt_filter_t));
{
/* version has been checked in coap_handle_message() */
/* if ( rcvd->pdu->hdr->version != COAP_DEFAULT_VERSION ) { */
/* debug("dropped packet with unknown version %u\n", rcvd->pdu->hdr->version); */
/* goto cleanup; */
/* } */
switch (rcvd->pdu->hdr->type) {
case COAP_MESSAGE_ACK:
/* find transaction in sendqueue to stop retransmission */
coap_remove_from_queue(&context->sendqueue, rcvd->id, &sent);
if (rcvd->pdu->hdr->code == 0)
goto cleanup;
/* if sent code was >= 64 the message might have been a
* notification. Then, we must flag the observer to be alive
* by setting obs->fail_cnt = 0. */
if (sent && COAP_RESPONSE_CLASS(sent->pdu->hdr->code) == 2) {
const str token =
{ sent->pdu->hdr->token_length, sent->pdu->hdr->token };
coap_touch_observer(context, &sent->remote, &token);
}
break;
case COAP_MESSAGE_RST :
/* We have sent something the receiver disliked, so we remove
* not only the transaction but also the subscriptions we might
* have. */
#ifndef WITH_CONTIKI
coap_log(LOG_ALERT, "got RST for message %u\n", ntohs(rcvd->pdu->hdr->id));
#else /* WITH_CONTIKI */
coap_log(LOG_ALERT, "got RST for message %u\n", uip_ntohs(rcvd->pdu->hdr->id));
#endif /* WITH_CONTIKI */
/* find transaction in sendqueue to stop retransmission */
coap_remove_from_queue(&context->sendqueue, rcvd->id, &sent);
if (sent)
coap_cancel(context, sent);
goto cleanup;
case COAP_MESSAGE_NON : /* check for unknown critical options */
if (coap_option_check_critical(context, rcvd->pdu, opt_filter) == 0)
goto cleanup;
break;
case COAP_MESSAGE_CON : /* check for unknown critical options */
if (coap_option_check_critical(context, rcvd->pdu, opt_filter) == 0) {
/* FIXME: send response only if we have received a request. Otherwise,
* send RST. */
response =
coap_new_error_response(rcvd->pdu, COAP_RESPONSE_CODE(402), opt_filter);
if (!response)
warn("coap_dispatch: cannot create error reponse\n");
else {
if (coap_send(context, &rcvd->local_if, &rcvd->remote, response)
== COAP_INVALID_TID) {
warn("coap_dispatch: error sending reponse\n");
}
coap_delete_pdu(response);
}
goto cleanup;
}
break;
}
/* Pass message to upper layer if a specific handler was
* registered for a request that should be handled locally. */
if (handle_locally(context, rcvd)) {
if (COAP_MESSAGE_IS_REQUEST(rcvd->pdu->hdr))
handle_request(context, rcvd);
else if (COAP_MESSAGE_IS_RESPONSE(rcvd->pdu->hdr))
handle_response(context, sent, rcvd);
else {
debug("dropped message with invalid code (%d.%02d)\n",
COAP_RESPONSE_CLASS(rcvd->pdu->hdr->code),
rcvd->pdu->hdr->code & 0x1f);
coap_send_message_type(context, &rcvd->local_if, &rcvd->remote,
rcvd->pdu, COAP_MESSAGE_RST);
}
}
cleanup:
coap_delete_node(sent);
coap_delete_node(rcvd);
}
}
int
coap_can_exit( coap_context_t *context ) {
return !context || (context->sendqueue == NULL);
}
#ifdef WITH_CONTIKI
/*---------------------------------------------------------------------------*/
/* CoAP message retransmission */
/*---------------------------------------------------------------------------*/
PROCESS_THREAD(coap_retransmit_process, ev, data)
{
coap_tick_t now;
coap_queue_t *nextpdu;
PROCESS_BEGIN();
debug("Started retransmit process\r\n");
while(1) {
PROCESS_YIELD();
if (ev == PROCESS_EVENT_TIMER) {
if (etimer_expired(&the_coap_context.retransmit_timer)) {
nextpdu = coap_peek_next(&the_coap_context);
coap_ticks(&now);
while (nextpdu && nextpdu->t <= now) {
coap_retransmit(&the_coap_context, coap_pop_next(&the_coap_context));
nextpdu = coap_peek_next(&the_coap_context);
}
/* need to set timer to some value even if no nextpdu is available */
etimer_set(&the_coap_context.retransmit_timer,
nextpdu ? nextpdu->t - now : 0xFFFF);
}
#ifndef WITHOUT_OBSERVE
if (etimer_expired(&the_coap_context.notify_timer)) {
coap_check_notify(&the_coap_context);
etimer_reset(&the_coap_context.notify_timer);
}
#endif /* WITHOUT_OBSERVE */
}
}
PROCESS_END();
}
/*---------------------------------------------------------------------------*/
#endif /* WITH_CONTIKI */
#ifdef WITH_LWIP
/* FIXME: retransmits that are not required any more due to incoming packages
* do *not* get cleared at the moment, the wakeup when the transmission is due
* is silently accepted. this is mainly due to the fact that the required
* checks are similar in two places in the code (when receiving ACK and RST)
* and that they cause more than one patch chunk, as it must be first checked
* whether the sendqueue item to be dropped is the next one pending, and later
* the restart function has to be called. nothing insurmountable, but it can
* also be implemented when things have stabilized, and the performance
* penality is minimal
*
* also, this completely ignores COAP_RESOURCE_CHECK_TIME.
* */
static void coap_retransmittimer_execute(void *arg)
{
coap_context_t *ctx = (coap_context_t*)arg;
coap_tick_t now;
coap_tick_t elapsed;
coap_queue_t *nextinqueue;
ctx->timer_configured = 0;
coap_ticks(&now);
elapsed = now - ctx->sendqueue_basetime; /* that's positive for sure, and unless we haven't been called for a complete wrapping cycle, did not wrap */
nextinqueue = coap_peek_next(ctx);
while (nextinqueue != NULL)
{
if (nextinqueue->t > elapsed) {
nextinqueue->t -= elapsed;
break;
} else {
elapsed -= nextinqueue->t;
coap_retransmit(ctx, coap_pop_next(ctx));
nextinqueue = coap_peek_next(ctx);
}
}
ctx->sendqueue_basetime = now;
coap_retransmittimer_restart(ctx);
}
static void coap_retransmittimer_restart(coap_context_t *ctx)
{
coap_tick_t now, elapsed, delay;
if (ctx->timer_configured)
{
printf("clearing\n");
sys_untimeout(coap_retransmittimer_execute, (void*)ctx);
ctx->timer_configured = 0;
}
if (ctx->sendqueue != NULL)
{
coap_ticks(&now);
elapsed = now - ctx->sendqueue_basetime;
if (ctx->sendqueue->t >= elapsed) {
delay = ctx->sendqueue->t - elapsed;
} else {
/* a strange situation, but not completely impossible.
*
* this happens, for example, right after
* coap_retransmittimer_execute, when a retransmission
* was *just not yet* due, and the clock ticked before
* our coap_ticks was called.
*
* not trying to retransmit anything now, as it might
* cause uncontrollable recursion; let's just try again
* with the next main loop run.
* */
delay = 0;
}
printf("scheduling for %d ticks\n", delay);
sys_timeout(delay, coap_retransmittimer_execute, (void*)ctx);
ctx->timer_configured = 1;
}
}
#endif
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