Merge branch 'bugfix/gateway_wrong_after_dhcp_renewal' into 'master'

fix(dhcp): Fixed incorrect address (mask/gateway) when dhcp renewal See merge request sdk/ESP8266_NONOS_SDK!291

Author: xcguang

VERSION

@@ -17,6 +17,6 @@ phy:
 gitlab:
  driver : 5a2a54b4
  json : f55d5fee
- lwip : f6bc9a8c
+ lwip : c7b8f692
  mbedtls : 82b93fe5
  smartconfig : ea1d4a13(v2.5.5)

lib/liblwip.a

@@ -1073,23 +1073,34 @@ dhcp_bind(struct netif *netif)
  /* copy offered network mask */
  ip_addr_copy(sn_mask, dhcp->offered_sn_mask);
  } else {
- /* subnet mask not given, choose a safe subnet mask given the network class */
- u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
- if (first_octet <= 127) {
- ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000));
- } else if (first_octet >= 192) {
- ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00));
- } else {
- ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000));
- }
+ /* subnet mask not given */
+ if (!ip_addr_isany(&netif->netmask)) {
+ /* if there is a previous subnet mask, use it */
+ ip_addr_copy(sn_mask, netif->netmask);
+ } else {
+ /* choose a safe subnet mask given the network class */
+ u8_t first_octet = ip4_addr1(&dhcp->offered_ip_addr);
+ if (first_octet <= 127) {
+ ip4_addr_set_u32(&sn_mask, PP_HTONL(0xff000000));
+ } else if (first_octet >= 192) {
+ ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffffff00));
+ } else {
+ ip4_addr_set_u32(&sn_mask, PP_HTONL(0xffff0000));
+ }
+ }
  }
 
- ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
  /* gateway address not given? */
- if (ip_addr_isany(&gw_addr)) {
+ if (!ip_addr_isany(&dhcp->offered_gw_addr)) {
+ /* Use the offered address */
+ ip_addr_copy(gw_addr, dhcp->offered_gw_addr);
+ } else if (!ip_addr_isany(&netif->gw)) {
+ /* Use the address previously received */
+ ip_addr_copy(gw_addr, netif->gw);
+ } else {
  /* copy network address */
  ip_addr_get_network(&gw_addr, &dhcp->offered_ip_addr, &sn_mask);
- /* use first host address on network as gateway */
+ /* assume gateway is xxx.xxx.xxx.1 */
  ip4_addr_set_u32(&gw_addr, ip4_addr_get_u32(&gw_addr) | PP_HTONL(0x00000001));
  }