lwip綁定端口失敗

使用lwip調試tcpserver時，出現綁定端口失敗，通過ifconfig發現是dhcp還未獲取到ip導致的，而程序中設置的是綁定192.168.1.42地址的端口，等到ip獲取成功之後就可以通過sal的bind進行綁定端口了。

msh >tcpserver
Bind fail!
close listener...
msh >tcpserver
Bind fail!
close listener...
msh >ifconfig
network interface device: e0 (Default)
MTU: 1500
MAC: 00 80 e1 12 26 2c 
FLAGS: UP LINK_UP INTERNET_DOWN DHCP_ENABLE ETHARP BROADCAST IGMP
ip address: 0.0.0.0
gw address: 0.0.0.0
net mask  : 0.0.0.0
dns server #0: 192.168.1.1
dns server #1: 0.0.0.0
msh >ifconfig
network interface device: e0 (Default)
MTU: 1500
MAC: 00 80 e1 12 26 2c 
FLAGS: UP LINK_UP INTERNET_UP DHCP_ENABLE ETHARP BROADCAST IGMP
ip address: 192.168.1.42
gw address: 192.168.1.1
net mask  : 255.255.255.0
dns server #0: 192.168.1.1
dns server #1: 0.0.0.0
msh >tcpserver
begin listing...