dhcp server:bugfix softap excedes the range of subnet

components/esp_common/src/esp_err_to_name.c

@@ -550,6 +550,9 @@ static const esp_err_msg_t esp_err_msg_table[] = {
 #   endif
 #   ifdef      ESP_ERR_ESP_NETIF_IP6_ADDR_FAILED
     ERR_TBL_IT(ESP_ERR_ESP_NETIF_IP6_ADDR_FAILED),              /* 20492 0x500c */
+#   endif
+#   ifdef      ESP_ERR_ESP_NETIF_DHCPS_START_FAILED
+    ERR_TBL_IT(ESP_ERR_ESP_NETIF_DHCPS_START_FAILED),           /* 20493 0x500d */
 #   endif
     // components/esp_common/include/esp_err.h
 #   ifdef      ESP_ERR_FLASH_BASE

components/esp_netif/include/esp_netif_types.h

@@ -33,6 +33,7 @@ extern "C" {
 #define ESP_ERR_ESP_NETIF_DNS_NOT_CONFIGURED    ESP_ERR_ESP_NETIF_BASE + 0x0A
 #define ESP_ERR_ESP_NETIF_MLD6_FAILED           ESP_ERR_ESP_NETIF_BASE + 0x0B
 #define ESP_ERR_ESP_NETIF_IP6_ADDR_FAILED       ESP_ERR_ESP_NETIF_BASE + 0x0C
+#define ESP_ERR_ESP_NETIF_DHCPS_START_FAILED    ESP_ERR_ESP_NETIF_BASE + 0x0D
 
 
 /** @brief Type of esp_netif_object server */

components/esp_netif/lwip/esp_netif_lwip.c

@@ -734,7 +734,11 @@ static esp_err_t esp_netif_start_api(esp_netif_api_msg_t *msg)
                 memcpy(&lwip_netmask, &default_ip->netmask, sizeof(struct ip4_addr));
                 dhcps_set_new_lease_cb(esp_netif_dhcps_cb);
                 dhcps_set_option_info(SUBNET_MASK, (void*)&lwip_netmask, sizeof(lwip_netmask));
-                dhcps_start(p_netif, lwip_ip);
+                if (dhcps_start(p_netif, lwip_ip) != ERR_OK) {
+                    ESP_LOGE(TAG, "DHCP server cannot be started");
+                    esp_netif->dhcps_status = ESP_NETIF_DHCP_INIT;
+                    return ESP_ERR_ESP_NETIF_DHCPS_START_FAILED;
+                }
                 esp_netif->dhcps_status = ESP_NETIF_DHCP_STARTED;
                 ESP_LOGD(TAG, "DHCP server started successfully");
                 esp_netif_update_default_netif(esp_netif, ESP_NETIF_STARTED);
@@ -1146,7 +1150,11 @@ static esp_err_t esp_netif_dhcps_start_api(esp_netif_api_msg_t *msg)
         memcpy(&lwip_netmask, &default_ip->netmask, sizeof(struct ip4_addr));
         dhcps_set_new_lease_cb(esp_netif_dhcps_cb);
         dhcps_set_option_info(SUBNET_MASK, (void*)&lwip_netmask, sizeof(lwip_netmask));
-        dhcps_start(p_netif, lwip_ip);
+        if (dhcps_start(p_netif, lwip_ip) != ERR_OK) {
+            ESP_LOGE(TAG, "DHCP server cannot be started");
+            esp_netif->dhcps_status = ESP_NETIF_DHCP_INIT;
+            return ESP_ERR_ESP_NETIF_DHCPS_START_FAILED;
+        }
         esp_netif->dhcps_status = ESP_NETIF_DHCP_STARTED;
         ESP_LOGD(TAG, "DHCP server started successfully");
         return ESP_OK;

components/lwip/apps/dhcpserver/dhcpserver.c

@@ -63,6 +63,21 @@
 #define DHCPS_DEBUG          0
 #define DHCPS_LOG printf
 
+
+#define IS_INVALID_SUBNET_MASK(x)  (((x-1) | x) != 0xFFFFFFFF)
+/* Notes:
+*  CIDR eliminates the traditional Class A, Class B and Class C addresses.
+ */
+#define IP_CLASS_HOST_NUM(mask)            (0xffffffff & ~mask)
+
+#define DHCP_CHECK_SUBNET_MASK_IP(mask)                                                                   \
+    do {                                                                                                  \
+        if (IS_INVALID_SUBNET_MASK(mask)) {                                                               \
+            DHCPS_LOG("dhcps: Illegal subnet mask.\n");                                                   \
+            return ERR_ARG;                                                                               \
+        }                                                                                                 \
+    } while (0)
+
 #define MAX_STATION_NUM CONFIG_LWIP_DHCPS_MAX_STATION_NUM
 
 #define DHCPS_STATE_OFFER 1
@@ -1079,6 +1094,8 @@ static void dhcps_poll_set(u32_t ip)
     u32_t softap_ip = 0, local_ip = 0;
     u32_t start_ip = 0;
     u32_t end_ip = 0;
+    u32_t temp_local_ip = 0;
+    u32_t host_num = 0;
 
     if (dhcps_poll.enable == true) {
         softap_ip = htonl(ip);
@@ -1102,17 +1119,22 @@ static void dhcps_poll_set(u32_t ip)
     if (dhcps_poll.enable == false) {
         local_ip = softap_ip = htonl(ip);
         softap_ip &= 0xFFFFFF00;
-        local_ip &= 0xFF;
+        temp_local_ip = local_ip &= 0xFF;
 
         if (local_ip >= 0x80) {
             local_ip -= DHCPS_MAX_LEASE;
+            temp_local_ip -= DHCPS_MAX_LEASE;
         } else {
             local_ip ++;
         }
 
         bzero(&dhcps_poll, sizeof(dhcps_poll));
+        host_num = IP_CLASS_HOST_NUM(htonl(s_dhcps_mask.addr));
+        if (host_num > DHCPS_MAX_LEASE) {
+            host_num = DHCPS_MAX_LEASE;
+        }
         dhcps_poll.start_ip.addr = softap_ip | local_ip;
-        dhcps_poll.end_ip.addr = softap_ip | (local_ip + DHCPS_MAX_LEASE - 1);
+        dhcps_poll.end_ip.addr = softap_ip | (temp_local_ip + host_num - 1);
         dhcps_poll.start_ip.addr = htonl(dhcps_poll.start_ip.addr);
         dhcps_poll.end_ip.addr = htonl(dhcps_poll.end_ip.addr);
     }
@@ -1139,8 +1161,11 @@ void dhcps_set_new_lease_cb(dhcps_cb_t cb)
  *              : info  -- The current ip info
  * Returns      : none
 *******************************************************************************/
-void dhcps_start(struct netif *netif, ip4_addr_t ip)
+err_t dhcps_start(struct netif *netif, ip4_addr_t ip)
 {
+    if (netif == NULL) {
+        return ERR_ARG;
+    }
     dhcps_netif = netif;
 
     if (dhcps_netif->dhcps_pcb != NULL) {
@@ -1152,6 +1177,7 @@ void dhcps_start(struct netif *netif, ip4_addr_t ip)
 
     if (pcb_dhcps == NULL || ip4_addr_isany_val(ip)) {
         printf("dhcps_start(): could not obtain pcb\n");
+        return ERR_ARG;
     }
 
     dhcps_netif->dhcps_pcb = pcb_dhcps;
@@ -1159,6 +1185,7 @@ void dhcps_start(struct netif *netif, ip4_addr_t ip)
     IP4_ADDR(&broadcast_dhcps, 255, 255, 255, 255);
 
     server_address.addr = ip.addr;
+    DHCP_CHECK_SUBNET_MASK_IP(htonl(s_dhcps_mask.addr));
     dhcps_poll_set(server_address.addr);
 
     client_address_plus.addr = dhcps_poll.start_ip.addr;
@@ -1168,7 +1195,7 @@ void dhcps_start(struct netif *netif, ip4_addr_t ip)
 #if DHCPS_DEBUG
     DHCPS_LOG("dhcps:dhcps_start->udp_recv function Set a receive callback handle_dhcp for UDP_PCB pcb_dhcps\n");
 #endif
-
+    return ERR_OK;
 }
 
 /******************************************************************************

components/lwip/include/apps/dhcpserver/dhcpserver.h

@@ -16,6 +16,7 @@
 
 #include "sdkconfig.h"
 #include "lwip/ip_addr.h"
+#include "lwip/err.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -86,7 +87,7 @@ static inline bool dhcps_dns_enabled (dhcps_offer_t offer)
     return (offer & OFFER_DNS) != 0;
 }
 
-void dhcps_start(struct netif *netif, ip4_addr_t ip);
+err_t dhcps_start(struct netif *netif, ip4_addr_t ip);
 void dhcps_stop(struct netif *netif);
 void *dhcps_option_info(u8_t op_id, u32_t opt_len);
 void dhcps_set_option_info(u8_t op_id, void *opt_info, u32_t opt_len);