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er-coap-observe.c 11.73 KiB
/*
* Copyright (c) 2013, Institute for Pervasive Computing, ETH Zurich
* 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.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
*
* This file is part of the Contiki operating system.
*/
/**
* \file
* CoAP module for observing resources (draft-ietf-core-observe-11).
* \author
* Matthias Kovatsch <kovatsch@inf.ethz.ch>
*/
#include <stdio.h>
#include <string.h>
#include "er-coap-observe.h"
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#define PRINT6ADDR(addr) PRINTF("[%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x]", ((uint8_t *)addr)[0], ((uint8_t *)addr)[1], ((uint8_t *)addr)[2], ((uint8_t *)addr)[3], ((uint8_t *)addr)[4], ((uint8_t *)addr)[5], ((uint8_t *)addr)[6], ((uint8_t *)addr)[7], ((uint8_t *)addr)[8], ((uint8_t *)addr)[9], ((uint8_t *)addr)[10], ((uint8_t *)addr)[11], ((uint8_t *)addr)[12], ((uint8_t *)addr)[13], ((uint8_t *)addr)[14], ((uint8_t *)addr)[15])
#define PRINTLLADDR(lladdr) PRINTF("[%02x:%02x:%02x:%02x:%02x:%02x]", (lladdr)->addr[0], (lladdr)->addr[1], (lladdr)->addr[2], (lladdr)->addr[3], (lladdr)->addr[4], (lladdr)->addr[5])
#else
#define PRINTF(...)
#define PRINT6ADDR(addr)
#define PRINTLLADDR(addr)
#endif
/*---------------------------------------------------------------------------*/
MEMB(observers_memb, coap_observer_t, COAP_MAX_OBSERVERS);
LIST(observers_list);
/*---------------------------------------------------------------------------*/
/*- Internal API ------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
static coap_observer_t *
add_observer(uip_ipaddr_t *addr, uint16_t port, const uint8_t *token,
size_t token_len, const char *uri, int uri_len)
{
/* Remove existing observe relationship, if any. */
coap_remove_observer_by_uri(addr, port, uri);
coap_observer_t *o = memb_alloc(&observers_memb);
if(o) { int max = sizeof(o->url) - 1;
if(max > uri_len) {
max = uri_len;
}
memcpy(o->url, uri, max);
o->url[max] = 0;
uip_ipaddr_copy(&o->addr, addr);
o->port = port;
o->token_len = token_len;
memcpy(o->token, token, token_len);
o->last_mid = 0;
PRINTF("Adding observer (%u/%u) for /%s [0x%02X%02X]\n",
list_length(observers_list) + 1, COAP_MAX_OBSERVERS,
o->url, o->token[0], o->token[1]);
list_add(observers_list, o);
}
return o;
}
/*---------------------------------------------------------------------------*/
/*- Removal -----------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void
coap_remove_observer(coap_observer_t *o)
{
PRINTF("Removing observer for /%s [0x%02X%02X]\n", o->url, o->token[0],
o->token[1]);
memb_free(&observers_memb, o);
list_remove(observers_list, o);
}
/*---------------------------------------------------------------------------*/
int
coap_remove_observer_by_client(uip_ipaddr_t *addr, uint16_t port)
{
int removed = 0;
coap_observer_t *obs = NULL;
for(obs = (coap_observer_t *)list_head(observers_list); obs;
obs = obs->next) {
PRINTF("Remove check client ");
PRINT6ADDR(addr);
PRINTF(":%u\n", port);
if(uip_ipaddr_cmp(&obs->addr, addr) && obs->port == port) {
coap_remove_observer(obs);
removed++;
}
}
return removed;
}
/*---------------------------------------------------------------------------*/
int
coap_remove_observer_by_token(uip_ipaddr_t *addr, uint16_t port,
uint8_t *token, size_t token_len)
{
int removed = 0;
coap_observer_t *obs = NULL;
for(obs = (coap_observer_t *)list_head(observers_list); obs;
obs = obs->next) {
PRINTF("Remove check Token 0x%02X%02X\n", token[0], token[1]);
if(uip_ipaddr_cmp(&obs->addr, addr) && obs->port == port
&& obs->token_len == token_len
&& memcmp(obs->token, token, token_len) == 0) {
coap_remove_observer(obs);
removed++;
}
}
return removed;}
/*---------------------------------------------------------------------------*/
int
coap_remove_observer_by_uri(uip_ipaddr_t *addr, uint16_t port,
const char *uri)
{
int removed = 0;
coap_observer_t *obs = NULL;
for(obs = (coap_observer_t *)list_head(observers_list); obs;
obs = obs->next) {
PRINTF("Remove check URL %p\n", uri);
if((addr == NULL
|| (uip_ipaddr_cmp(&obs->addr, addr) && obs->port == port))
&& (obs->url == uri || memcmp(obs->url, uri, strlen(obs->url)) == 0)) {
coap_remove_observer(obs);
removed++;
}
}
return removed;
}
/*---------------------------------------------------------------------------*/
int
coap_remove_observer_by_mid(uip_ipaddr_t *addr, uint16_t port, uint16_t mid)
{
int removed = 0;
coap_observer_t *obs = NULL;
for(obs = (coap_observer_t *)list_head(observers_list); obs;
obs = obs->next) {
PRINTF("Remove check MID %u\n", mid);
if(uip_ipaddr_cmp(&obs->addr, addr) && obs->port == port
&& obs->last_mid == mid) {
coap_remove_observer(obs);
removed++;
}
}
return removed;
}
/*---------------------------------------------------------------------------*/
/*- Notification ------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
void
coap_notify_observers(resource_t *resource)
{
coap_notify_observers_sub(resource, NULL);
}
void
coap_notify_observers_sub(resource_t *resource, const char *subpath)
{
/* build notification */
coap_packet_t notification[1]; /* this way the packet can be treated as pointer as usual */
coap_packet_t request[1]; /* this way the packet can be treated as pointer as usual */
coap_observer_t *obs = NULL;
int url_len, obs_url_len;
char url[COAP_OBSERVER_URL_LEN];
url_len = strlen(resource->url);
strncpy(url, resource->url, COAP_OBSERVER_URL_LEN - 1);
if(url_len < COAP_OBSERVER_URL_LEN - 1 && subpath != NULL) {
strncpy(&url[url_len], subpath, COAP_OBSERVER_URL_LEN - url_len - 1);
}
/* Ensure url is null terminated because strncpy does not guarantee this */
url[COAP_OBSERVER_URL_LEN - 1] = '\0';
/* url now contains the notify URL that needs to match the observer */
PRINTF("Observe: Notification from %s\n", url);
coap_init_message(notification, COAP_TYPE_NON, CONTENT_2_05, 0);
/* create a "fake" request for the URI */
coap_init_message(request, COAP_TYPE_CON, COAP_GET, 0); coap_set_header_uri_path(request, url);
/* iterate over observers */
url_len = strlen(url);
for(obs = (coap_observer_t *)list_head(observers_list); obs;
obs = obs->next) {
obs_url_len = strlen(obs->url);
/* Do a match based on the parent/sub-resource match so that it is
possible to do parent-node observe */
if((obs_url_len == url_len
|| (obs_url_len > url_len
&& (resource->flags & HAS_SUB_RESOURCES)
&& obs->url[url_len] == '/'))
&& strncmp(url, obs->url, url_len) == 0) {
coap_transaction_t *transaction = NULL;
/*TODO implement special transaction for CON, sharing the same buffer to allow for more observers */
if((transaction = coap_new_transaction(coap_get_mid(), &obs->addr, obs->port))) {
if(obs->obs_counter % COAP_OBSERVE_REFRESH_INTERVAL == 0) {
PRINTF(" Force Confirmable for\n");
notification->type = COAP_TYPE_CON;
}
PRINTF(" Observer ");
PRINT6ADDR(&obs->addr);
PRINTF(":%u\n", obs->port);
/* update last MID for RST matching */
obs->last_mid = transaction->mid;
/* prepare response */
notification->mid = transaction->mid;
resource->get_handler(request, notification,
transaction->packet + COAP_MAX_HEADER_SIZE,
REST_MAX_CHUNK_SIZE, NULL);
if(notification->code < BAD_REQUEST_4_00) {
coap_set_header_observe(notification, (obs->obs_counter)++);
/* mask out to keep the CoAP observe option length <= 3 bytes */
obs->obs_counter &= 0xffffff;
}
coap_set_token(notification, obs->token, obs->token_len);
transaction->packet_len =
coap_serialize_message(notification, transaction->packet);
coap_send_transaction(transaction);
}
}
}
}
/*---------------------------------------------------------------------------*/
void
coap_observe_handler(resource_t *resource, void *request, void *response)
{
coap_packet_t *const coap_req = (coap_packet_t *)request;
coap_packet_t *const coap_res = (coap_packet_t *)response;
coap_observer_t *obs;
if(coap_req->code == COAP_GET && coap_res->code < 128) { /* GET request and response without error code */
if(IS_OPTION(coap_req, COAP_OPTION_OBSERVE)) {
if(coap_req->observe == 0) {
obs = add_observer(&UIP_IP_BUF->srcipaddr, UIP_UDP_BUF->srcport,
coap_req->token, coap_req->token_len,
coap_req->uri_path, coap_req->uri_path_len);
if(obs) {
coap_set_header_observe(coap_res, (obs->obs_counter)++); /* mask out to keep the CoAP observe option length <= 3 bytes */
obs->obs_counter &= 0xffffff;
/*
* Following payload is for demonstration purposes only.
* A subscription should return the same representation as a normal GET.
* Uncomment if you want an information about the avaiable observers.
*/
#if 0
static char content[16];
coap_set_payload(coap_res,
content,
snprintf(content, sizeof(content), "Added %u/%u",
list_length(observers_list),
COAP_MAX_OBSERVERS));
#endif
} else {
coap_res->code = SERVICE_UNAVAILABLE_5_03;
coap_set_payload(coap_res, "TooManyObservers", 16);
}
} else if(coap_req->observe == 1) {
/* remove client if it is currently observe */
coap_remove_observer_by_token(&UIP_IP_BUF->srcipaddr,
UIP_UDP_BUF->srcport, coap_req->token,
coap_req->token_len);
}
}
}
}
/*---------------------------------------------------------------------------*/