lwip 中ARP 请求包 中目的IP地址为发送方地址，

youk110

在做LWIP移植过程中，板子与PC机不能建立通信，仿真发现：接收来自pc机的ARP request packet 中的目的IP地址是PC机的IP地址，串口输出结果：etharp_arp_input: incoming ARP request
etharp_arp_input: ARP request was not for us.
这是什么原因啊？

youk110

虽说现在能够TCP通信和ping相通了，但还是想弄明白ARP协议工作流程，在仿真调试的时候还是出现“如题的现象”？先把仿真结果和串口输出信息附上，有哪位大侠解释下啊？

jlink仿真接收的数据包

接收的arp数据包相关信息

串口输出ARP相关调试信息

串口输出ARP相关调试信息
电脑信息：IP 192.168.0.54  MAC 00-30-48-7D-F0-2E
板子信息: IP 192.168.0.10   MAC  00-80-48-12-34-56

youk110

这是不是类似于lwip中etharp_gratuitous（）函数的功能啊，是不是PC网卡发送的无回报（gratuitous）ARP请求啊？？

youk110

开启lwip的调试信息后输出如下：
[mw_shl_code=c,true]PHY works in 100Mbps full-duplex mode!
netif: added interface en IP addr 192.168.0.10 netmask 255.255.255.0 gw 192.168.0.1
netif: setting default interface en
etharp_request: sending ARP request.
pbuf_alloc(length=42)
pbuf_alloc(length=42) == 20000350
etharp_raw: sending raw ARP packet.
TSRI transfer successfully!
pbuf_free(20000350)
pbuf_free: deallocating 20000350
there are some packets coming!
pbuf_alloc(length=64)
pbuf_alloc: allocated pbuf 200062a4
pbuf_alloc(length=64) == 200062a4
ethernet_input: dest:ff:ff:ff:ff:ff:ff, src:00:30:48:7d:f0:2e, type:806
etharp_update_arp_entry: 192.168.0.54 - 00:30:48:7d:f0:2e
etharp_find_entry: found empty entry 0
etharp_find_entry: no empty entry found and not allowed to recycle
etharp_arp_input: incoming ARP request
etharp_arp_input: ARP request was not for us.
pbuf_free(200062a4)
pbuf_free: deallocating 200062a4
[/mw_shl_code]

youk110

终于ping通了，自己移植ST官方lwipopts.h的时候直接copy过来的，把以下代码删除就可以ping通了
[mw_shl_code=c,true]   ---------- Checksum options ----------
   --------------------------------------
*/

/*
The STM32F4x7 allows computing and verifying the IP, UDP, TCP and ICMP checksums by hardware:
- To use this feature let the following define uncommented.
- To disable it and process by CPU comment the  the checksum.
*/
#define CHECKSUM_BY_HARDWARE


#ifdef CHECKSUM_BY_HARDWARE
  /* CHECKSUM_GEN_IP==0: Generate checksums by hardware for outgoing IP packets.*/
  #define CHECKSUM_GEN_IP                 0
  /* CHECKSUM_GEN_UDP==0: Generate checksums by hardware for outgoing UDP packets.*/
  #define CHECKSUM_GEN_UDP                0
  /* CHECKSUM_GEN_TCP==0: Generate checksums by hardware for outgoing TCP packets.*/
  #define CHECKSUM_GEN_TCP                0
  /* CHECKSUM_CHECK_IP==0: Check checksums by hardware for incoming IP packets.*/
  #define CHECKSUM_CHECK_IP               0
  /* CHECKSUM_CHECK_UDP==0: Check checksums by hardware for incoming UDP packets.*/
  #define CHECKSUM_CHECK_UDP              0
  /* CHECKSUM_CHECK_TCP==0: Check checksums by hardware for incoming TCP packets.*/
  #define CHECKSUM_CHECK_TCP              0
  /* CHECKSUM_CHECK_ICMP==0: Check checksums by hardware for incoming ICMP packets.*/
  #define CHECKSUM_GEN_ICMP               0
#else
  /* CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing IP packets.*/
  #define CHECKSUM_GEN_IP                 1
  /* CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing UDP packets.*/
  #define CHECKSUM_GEN_UDP                1
  /* CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing TCP packets.*/
  #define CHECKSUM_GEN_TCP                1
  /* CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP packets.*/
  #define CHECKSUM_CHECK_IP               1
  /* CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming UDP packets.*/
  #define CHECKSUM_CHECK_UDP              1
  /* CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming TCP packets.*/
  #define CHECKSUM_CHECK_TCP              1
  /* CHECKSUM_CHECK_ICMP==1: Check checksums by hardware for incoming ICMP packets.*/
  #define CHECKSUM_GEN_ICMP               1
#endif
[/mw_shl_code]