esp-idf/components/esp_netif/esp_netif_objects.c
David Cermak 36735f4d77 fix(esp_netif): Lock netif list with TCPIP context
This commit removes the lock from the list manipulation code in esp_netif_objects.c,
 because we already have another lock/task context for lwip.
So the list manipulation is unsafe and safety must be assured by the stack layer
(in esp_netif_lwip).
Problems with current locking:
* implementation of locking was wrong -- lazy init style of creating the mutex is not
  thread safe (and destroying it if we have no interface makes the problem exhibit very frequently)
* locking only the list won't solve issues when assessing interfaces atomically
* maintaining multiple locks is problematic, as we often switch between
lwip context and user context in internal implementation of esp_netif_lwip

Closes https://github.com/espressif/esp-idf/issues/12261
2023-10-13 15:54:53 +02:00

123 lines
3.1 KiB
C

/*
* SPDX-FileCopyrightText: 2015-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "esp_netif.h"
#include "sys/queue.h"
#include "esp_log.h"
#include "esp_netif_private.h"
#include <string.h>
//
// Purpose of this module is to provide list of esp-netif structures
// - this module has no dependency on a specific network stack (lwip)
//
static const char *TAG = "esp_netif_objects";
typedef struct slist_netifs_s slist_netifs_t;
struct slist_netifs_s {
esp_netif_t *netif;
SLIST_ENTRY(slist_netifs_s) next;
};
SLIST_HEAD(slisthead, slist_netifs_s) s_head = { .slh_first = NULL, };
static size_t s_esp_netif_counter = 0;
ESP_EVENT_DEFINE_BASE(IP_EVENT);
//
// List manipulation functions
//
esp_err_t esp_netif_add_to_list_unsafe(esp_netif_t *netif)
{
struct slist_netifs_s *item = calloc(1, sizeof(struct slist_netifs_s));
ESP_LOGV(TAG, "%s %p", __func__, netif);
if (item == NULL) {
return ESP_ERR_NO_MEM;
}
item->netif = netif;
SLIST_INSERT_HEAD(&s_head, item, next);
++s_esp_netif_counter;
ESP_LOGD(TAG, "%s netif added successfully (total netifs: %" PRIu32 ")", __func__, (uint32_t)s_esp_netif_counter);
return ESP_OK;
}
esp_err_t esp_netif_remove_from_list_unsafe(esp_netif_t *netif)
{
struct slist_netifs_s *item;
ESP_LOGV(TAG, "%s %p", __func__, netif);
SLIST_FOREACH(item, &s_head, next) {
if (item->netif == netif) {
SLIST_REMOVE(&s_head, item, slist_netifs_s, next);
assert(s_esp_netif_counter > 0);
--s_esp_netif_counter;
ESP_LOGD(TAG, "%s netif successfully removed (total netifs: %" PRIu32 ")", __func__, (uint32_t)s_esp_netif_counter);
free(item);
return ESP_OK;
}
}
return ESP_ERR_NOT_FOUND;
}
size_t esp_netif_get_nr_of_ifs(void)
{
return s_esp_netif_counter;
}
// This API is inherently unsafe
// suggest that users call from esp_netif_tcpip_exec()
esp_netif_t* esp_netif_next(esp_netif_t* netif)
{
return esp_netif_next_unsafe(netif);
}
esp_netif_t* esp_netif_next_unsafe(esp_netif_t* netif)
{
ESP_LOGV(TAG, "%s %p", __func__, netif);
struct slist_netifs_s *item;
// Getting the first netif if argument is NULL
if (netif == NULL) {
item = SLIST_FIRST(&s_head);
return (item == NULL) ? NULL : item->netif;
}
// otherwise the next one (after the supplied netif)
SLIST_FOREACH(item, &s_head, next) {
if (item->netif == netif) {
item = SLIST_NEXT(item, next);
return (item == NULL) ? NULL : item->netif;
}
}
return NULL;
}
bool esp_netif_is_netif_listed(esp_netif_t *esp_netif)
{
struct slist_netifs_s *item;
SLIST_FOREACH(item, &s_head, next) {
if (item->netif == esp_netif) {
return true;
}
}
return false;
}
esp_netif_t *esp_netif_get_handle_from_ifkey_unsafe(const char *if_key)
{
struct slist_netifs_s *item;
SLIST_FOREACH(item, &s_head, next) {
esp_netif_t *esp_netif = item->netif;
if (strcmp(if_key, esp_netif_get_ifkey(esp_netif)) == 0) {
return esp_netif;
}
}
return NULL;
}