fix(dhcp server): Fix dhcp server address pool issue

components/lwip/apps/dhcpserver/dhcpserver.c

@@ -78,6 +78,19 @@
  } \
  } while (0)
 
+#define DHCP_CHECK_IP_MATCH_SUBNET_MASK(mask, ip) \
+ u32_t start_ip = 0; \
+ u32_t end_ip = 0; \
+ do { \
+ start_ip = ip & mask; \
+ end_ip = start_ip | ~mask; \
+ if (ip == end_ip || ip == start_ip) \
+ { \
+ DHCPS_LOG("dhcps: ip address and subnet mask do not match.\n"); \
+ return ERR_ARG; \
+ } \
+ } while (0)
+
 #define MAX_STATION_NUM CONFIG_LWIP_DHCPS_MAX_STATION_NUM
 
 #define DHCPS_STATE_OFFER 1
@@ -1091,50 +1104,48 @@ static void handle_dhcp(void *arg,
 *******************************************************************************/
 static void dhcps_poll_set(u32_t ip)
 {
- u32_t softap_ip = 0, local_ip = 0;
+ u32_t server_ip = 0;
  u32_t start_ip = 0;
  u32_t end_ip = 0;
- u32_t temp_local_ip = 0;
- u32_t host_num = 0;
+ u32_t range_start_ip = 0;
+ u32_t range_end_ip = 0;
 
  if (dhcps_poll.enable == true) {
- softap_ip = htonl(ip);
+ server_ip = htonl(ip);
  start_ip = htonl(dhcps_poll.start_ip.addr);
  end_ip = htonl(dhcps_poll.end_ip.addr);
 
  /*config ip information can't contain local ip*/
- if ((start_ip <= softap_ip) && (softap_ip <= end_ip)) {
+ if ((start_ip <= server_ip) && (server_ip <= end_ip)) {
  dhcps_poll.enable = false;
  } else {
  /*config ip information must be in the same segment as the local ip*/
- softap_ip >>= 8;
-
- if (((start_ip >> 8 != softap_ip) || (end_ip >> 8 != softap_ip))
- || (end_ip - start_ip > DHCPS_MAX_LEASE)) {
+ if (!ip4_addr_netcmp(&dhcps_poll.start_ip, &server_address, &s_dhcps_mask)
+ || !ip4_addr_netcmp(&dhcps_poll.end_ip, &server_address, &s_dhcps_mask)
+ || (end_ip - start_ip + 1 > DHCPS_MAX_LEASE)) {
  dhcps_poll.enable = false;
  }
  }
  }
 
  if (dhcps_poll.enable == false) {
- local_ip = softap_ip = htonl(ip);
- softap_ip &= 0xFFFFFF00;
- temp_local_ip = local_ip &= 0xFF;
+ server_ip = htonl(ip);
+ range_start_ip = server_ip & htonl(s_dhcps_mask.addr);
+ range_end_ip = range_start_ip | ~htonl(s_dhcps_mask.addr);
 
- if (local_ip >= 0x80) {
- local_ip -= DHCPS_MAX_LEASE;
- temp_local_ip -= DHCPS_MAX_LEASE;
+ if (server_ip - range_start_ip > range_end_ip - server_ip) {
+ range_start_ip = range_start_ip + 1;
+ range_end_ip = server_ip - 1;
  } else {
- local_ip ++;
+ range_start_ip = server_ip + 1;
+ range_end_ip = range_end_ip - 1;
  }
-
- 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;
+ if (range_end_ip - range_start_ip + 1 > DHCPS_MAX_LEASE) {
+ range_end_ip = range_start_ip + DHCPS_MAX_LEASE - 1;
  }
- dhcps_poll.start_ip.addr = softap_ip | local_ip;
- dhcps_poll.end_ip.addr = softap_ip | (temp_local_ip + host_num - 1);
+ bzero(&dhcps_poll, sizeof(dhcps_poll));
+ dhcps_poll.start_ip.addr = range_start_ip;
+ dhcps_poll.end_ip.addr = range_end_ip;
  dhcps_poll.start_ip.addr = htonl(dhcps_poll.start_ip.addr);
  dhcps_poll.end_ip.addr = htonl(dhcps_poll.end_ip.addr);
  }
@@ -1176,7 +1187,7 @@ err_t dhcps_start(struct netif *netif, ip4_addr_t ip)
  struct udp_pcb *pcb_dhcps = dhcps_netif->dhcps_pcb;
 
  if (pcb_dhcps == NULL || ip4_addr_isany_val(ip)) {
- printf("dhcps_start(): could not obtain pcb\n");
+ DHCPS_LOG("dhcps_start(): could not obtain pcb\n");
  return ERR_ARG;
  }
 
@@ -1186,6 +1197,7 @@ err_t dhcps_start(struct netif *netif, ip4_addr_t ip)
 
  server_address.addr = ip.addr;
  DHCP_CHECK_SUBNET_MASK_IP(htonl(s_dhcps_mask.addr));
+ DHCP_CHECK_IP_MATCH_SUBNET_MASK(htonl(s_dhcps_mask.addr), htonl(ip.addr));
  dhcps_poll_set(server_address.addr);
 
  client_address_plus.addr = dhcps_poll.start_ip.addr;