diff --git a/components/esp_netif/lwip/esp_netif_lwip.c b/components/esp_netif/lwip/esp_netif_lwip.c index ef41ef19e548..311462b96be4 100644 --- a/components/esp_netif/lwip/esp_netif_lwip.c +++ b/components/esp_netif/lwip/esp_netif_lwip.c @@ -2258,6 +2258,23 @@ esp_err_t esp_netif_dhcps_option_api(esp_netif_api_msg_t *msg) break; } case ESP_NETIF_SUBNET_MASK: { + esp_netif_ip_info_t *default_ip = esp_netif->ip_info; + ip4_addr_t *config_netmask = (ip4_addr_t *)opt->val; + if (!memcmp(&default_ip->netmask, config_netmask, sizeof(struct ip4_addr))) { + ESP_LOGE(TAG, "Please use esp_netif_set_ip_info interface to configure subnet mask"); + /* + * This API directly changes the subnet mask of dhcp server + * but the subnet mask of the network interface has not changed + * If you need to change the subnet mask of dhcp server + * you need to change the subnet mask of the network interface first. + * If the subnet mask of dhcp server is changed + * and the subnet mask of network interface is inconsistent + * with the subnet mask of dhcp sever, it may lead to the failure of sending packets. + * If want to configure the subnet mask of dhcp server + * please use esp_netif_set_ip_info to change the subnet mask of network interface first. + */ + return ESP_ERR_ESP_NETIF_INVALID_PARAMS; + } memcpy(opt_info, opt->val, opt->len); break; }