目录

• API
• 流程
• sockaddr_in 初始化
• 示例

API

推荐在Socket层面的API，一共只有如下这么多：
#include “socket.h”

int lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen); int lwip_bind(int s, const struct sockaddr *name, socklen_t namelen); int lwip_shutdown(int s, int how); int lwip_getpeername (int s, struct sockaddr *name, socklen_t *namelen); int lwip_getsockname (int s, struct sockaddr *name, socklen_t *namelen); int lwip_getsockopt (int s, int level, int optname, void *optval, socklen_t *optlen); int lwip_setsockopt (int s, int level, int optname, const void *optval, socklen_t optlen);  int lwip_close(int s); int lwip_connect(int s, const struct sockaddr *name, socklen_t namelen); int lwip_listen(int s, int backlog); ssize_t lwip_recv(int s, void *mem, size_t len, int flags); ssize_t lwip_read(int s, void *mem, size_t len); ssize_t lwip_readv(int s, const struct iovec *iov, int iovcnt); ssize_t lwip_recvfrom(int s, void *mem, size_t len, int flags,       struct sockaddr *from, socklen_t *fromlen); ssize_t lwip_recvmsg(int s, struct msghdr *message, int flags); ssize_t lwip_send(int s, const void *dataptr, size_t size, int flags); ssize_t lwip_sendmsg(int s, const struct msghdr *message, int flags); ssize_t lwip_sendto(int s, const void *dataptr, size_t size, int flags,     const struct sockaddr *to, socklen_t tolen); int lwip_socket(int domain, int type, int protocol); ssize_t lwip_write(int s, const void *dataptr, size_t size); ssize_t lwip_writev(int s, const struct iovec *iov, int iovcnt); #if LWIP_SOCKET_SELECT int lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,                 struct timeval *timeout); #endif #if LWIP_SOCKET_POLL int lwip_poll(struct pollfd *fds, nfds_t nfds, int timeout); #endif int lwip_ioctl(int s, long cmd, void *argp); int lwip_fcntl(int s, int cmd, int val); const char *lwip_inet_ntop(int af, const void *src, char *dst, socklen_t size); int lwip_inet_pton(int af, const char *src, void *dst); 

流程

如果做client，操作流程如下

如果做server，操作流程如下

sockaddr_in 初始化

struct sockaddr_in {   u8_t            sin_len;   sa_family_t     sin_family;   in_port_t       sin_port;   struct in_addr  sin_addr; #define SIN_ZERO_LEN 8   char            sin_zero[SIN_ZERO_LEN]; }; 

示例

TCP server send

int ret;                          //保存lwip api返回值，一般来说不是-1就没问题   int server_fd;                    //保存socket描述符，由lwip_socket返回，如果是-1那么描述符分配失败   struct sockaddr_in server_addr;   //保存socket相应的地址和端口号   int client_fd = 0;   struct sockaddr_in client_addr;   //保存socket相应的地址和端口号   uint32_t client_addr_sz = 0; restart:   server_fd = lwip_socket(AF_INET, SOCK_STREAM, IPPROTO_IP); //IPV4，TCP，IP   PROJ_ASSERT(server_fd != -1);   memset(&server_addr, 0, sizeof(struct sockaddr_in));   server_addr.sin_family = AF_INET;                      //IPV4   server_addr.sin_port = htons(49850);                   //htons用于交换port高低字节   server_addr.sin_addr.s_addr = htonl(INADDR_ANY);       //htonl用于交换s_addr高低字节    osDelay(10);   ret = lwip_bind(server_fd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));   if(ret == -1)goto err;    ret = lwip_listen(server_fd, 0);   if(ret == -1)goto err;  reaccept:   client_fd = lwip_accept(server_fd, (struct sockaddr *)&client_addr, &client_addr_sz);   PROJ_ASSERT(client_fd != -1);    for(;;)   {      ret = lwip_write(client_fd, "hello from lwip_func\n", sizeof("hello from lwip_func\n"));     if(ret == -1)     {       lwip_close(client_fd);       goto reaccept;     }     osDelay(100);   } err:     lwip_close(server_fd);     goto restart;