lwIP学习笔记-移植

typedef unsigned char  u8_t;

#define U16_F  "hu"

#define BYTE_ORDER  LITTLE_ENDIAN
或者
#define BYTE_ORDER  BIG_ENDIAN

#define LWIP_PLATFORM_BYTESWAP  1
#define LWIP_PLATFORM_HTONS(x)  ((((u16_t)(x))>>8) | (((x)&0xFF)<<8))
#define LWIP_PLATFORM_HTONL(x)  ((((u32_t)(x))>>24) | (((x)&0xFF0000)>>8) | (((x)&0xFF00)<<8) | (((x)&0xFF)<<24))

#define LWIP_CHKSUM_ALGORITHM 2

u16_t my_chksum(void *dataptr, u16_t len);
#define LWIP_CHKSUM  my_chksum

#ifdef PACK_STRUCT_USE_INCLUDES
#  include "arch/bpstruct.h"
#endif
PACK_STRUCT_BEGIN
struct <structure_name> {
  PACK_STRUCT_FIELD(<type> <field>);
  PACK_STRUCT_FIELD(<type> <field>);
  <...>
} PACK_STRUCT_STRUCT;
PACK_STRUCT_END
#ifdef PACK_STRUCT_USE_INCLUDES
#  include "arch/epstruct.h"
#endif

#define PACK_STRUCT_FIELD(x) x __attribute__((packed))
#define PACK_STRUCT_STRUCT __attribute__((packed))
#define PACK_STRUCT_BEGIN
#define PACK_STRUCT_END

LWIP_PLATFORM_DIAG(x)  non-fatal，只是打印message
LWIP_PLATFORM_ASSERT(x)  fatal，打印message，然后停止执行

#define SYS_ARCH_DECL_PROTECT(lev) sys_prot_t lev
#define SYS_ARCH_PROTECT(lev) lev = sys_arch_protect()
#define SYS_ARCH_UNPROTECT(lev) sys_arch_unprotect(lev)

sys_sem_t sys_sem_new(u8_t count);
void sys_sem_free(sys_sem_t sem);
void sys_sem_signal(sys_sem_t sem);
u32_t sys_arch_sem_wait(sys_sem_t sem, u32_t timeout);

sys_mbox_t sys_mbox_new(int size);
void sys_mbox_free(sys_mbox_t mbox);
void sys_mbox_post(sys_mbox_t mbox, void *msg);
u32_t sys_arch_mbox_fetch(sys_mbox_t mbox, void **msg, u32_t timeout);
u32_t sys_arch_mbox_tryfetch(sys_mbox_t mbox, void **msg);
err_t sys_mbox_trypost(sys_mbox_t mbox, void *msg);

sys_sem_t
sys_mbox_t
sys_thread_t

sys_prot_t sys_arch_protect(void);
void sys_arch_unprotect(sys_prot_t pval);

struct ethernetif {
  struct eth_addr *ethaddr;
  /* Add whatever per-interface state that is needed here. */
  //在这里可以添加自己的私有数据结构，不是必须的
};

static void low_level_init(struct netif *netif);
static err_t low_level_output(struct netif *netif, struct pbuf *p);
static struct pbuf *low_level_input(struct netif *netif);

static void low_level_init(struct netif *netif)
{
  struct ethernetif *ethernetif = netif->state;

  /* set MAC hardware address length */
  netif->hwaddr_len = ETHARP_HWADDR_LEN;

  //添加网卡的mac地址
  /* set MAC hardware address */
  netif->hwaddr[0] = ;
  netif->hwaddr[1] = ;
  netif->hwaddr[2] = ;
  netif->hwaddr[3] = ;
  netif->hwaddr[4] = ;
  netif->hwaddr[5] = ;

  /* maximum transfer unit */
  netif->mtu = 1500;

  /* device capabilities */
  /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
  netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;

#if LWIP_IPV6 && LWIP_IPV6_MLD
  /*
   * For hardware/netifs that implement MAC filtering.
   * All-nodes link-local is handled by default, so we must let the hardware know
   * to allow multicast packets in.
   * Should set mld_mac_filter previously. */
  if (netif->mld_mac_filter != NULL) {
    ip6_addr_t ip6_allnodes_ll;
    ip6_addr_set_allnodes_linklocal(&ip6_allnodes_ll);
    netif->mld_mac_filter(netif, &ip6_allnodes_ll, NETIF_ADD_MAC_FILTER);
  }
#endif /* LWIP_IPV6 && LWIP_IPV6_MLD */

  //其他相关的初始化
  /* Do whatever else is needed to initialize interface. */
}

static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
  struct ethernetif *ethernetif = netif->state;
  struct pbuf *q;

  //实现初始化transfer()
  initiate transfer();

#if ETH_PAD_SIZE
  pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
#endif

  for (q = p; q != NULL; q = q->next) {
    /* Send the data from the pbuf to the interface, one pbuf at a time. The size of the data in each pbuf is kept in the ->len variable. */
    //实现发送data，从pbuf到网卡
    send data from(q->payload, q->len);
  }

  //实现触发发送
  signal that packet should be sent();

  MIB2_STATS_NETIF_ADD(netif, ifoutoctets, p->tot_len);
  if (((u8_t*)p->payload)[0] & 1) {
    /* broadcast or multicast packet*/
    MIB2_STATS_NETIF_INC(netif, ifoutnucastpkts);
  } else {
    /* unicast packet */
    MIB2_STATS_NETIF_INC(netif, ifoutucastpkts);
  }
  /* increase ifoutdiscards or ifouterrors on error */

#if ETH_PAD_SIZE
  pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
#endif

  LINK_STATS_INC(link.xmit);

  return ERR_OK;
}

static struct pbuf *low_level_input(struct netif *netif)
{
  struct ethernetif *ethernetif = netif->state;
  struct pbuf *p, *q;
  u16_t len;

  //获得接收数据长度，赋值给len
  /* Obtain the size of the packet and put it into the "len" variable. */
  len = ;

#if ETH_PAD_SIZE
  len += ETH_PAD_SIZE; /* allow room for Ethernet padding */
#endif

  /* We allocate a pbuf chain of pbufs from the pool. */
  p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);

  if (p != NULL) {

#if ETH_PAD_SIZE
    pbuf_header(p, -ETH_PAD_SIZE); /* drop the padding word */
#endif

    /* We iterate over the pbuf chain until we have read the entire packet into the pbuf. */
    for (q = p; q != NULL; q = q->next) {
      /* Read enough bytes to fill this pbuf in the chain. The available data in the pbuf is given by the q->len variable. This does not necessarily have to be a memcpy, you can also preallocate pbufs for a DMA-enabled MAC and after receiving truncate it to the actually received size. In this case, ensure the tot_len member of the pbuf is the sum of the chained pbuf len members. */
      //实现读入数据
      read data into(q->payload, q->len);
    }
    //实现数据已经读取Ack
    acknowledge that packet has been read();

    MIB2_STATS_NETIF_ADD(netif, ifinoctets, p->tot_len);
    if (((u8_t*)p->payload)[0] & 1) {
      /* broadcast or multicast packet*/
      MIB2_STATS_NETIF_INC(netif, ifinnucastpkts);
    } else {
      /* unicast packet*/
      MIB2_STATS_NETIF_INC(netif, ifinucastpkts);
    }
#if ETH_PAD_SIZE
    pbuf_header(p, ETH_PAD_SIZE); /* reclaim the padding word */
#endif

    LINK_STATS_INC(link.recv);
  } else {
    //实现丢弃数据包
    drop packet();
    LINK_STATS_INC(link.memerr);
    LINK_STATS_INC(link.drop);
    MIB2_STATS_NETIF_INC(netif, ifindiscards);
  }

  return p;
}