先了解應(yīng)用層和協(xié)議棧是怎么交互消息的

先看內(nèi)核消息數(shù)據(jù)結(jié)構(gòu)

/* tcp/ip內(nèi)核消息類型 */ enum tcpip_msg_type {TCPIP_MSG_API, //調(diào)用APITCPIP_MSG_INPKT, //底層數(shù)據(jù)包輸入TCPIP_MSG_TIMEOUT, //注冊(cè)一個(gè)定時(shí)事件TCPIP_MSG_UNTIMEOUT, //刪除一個(gè)定時(shí)事件TCPIP_MSG_CALLBACK, //上層回調(diào)函數(shù)TCPIP_MSG_CALLBACK_STATIC //上層回調(diào)函數(shù)(消息為靜態(tài)) };/* tcp/ip內(nèi)核消息 */ struct tcpip_msg {enum tcpip_msg_type type; //消息類型sys_sem_t *sem; //信號(hào)量指針union {/* API消息 */struct api_msg *apimsg;/* 底層數(shù)據(jù)包輸入消息 */struct {struct pbuf *p; //數(shù)據(jù)包pbuf指針struct netif *netif; //網(wǎng)絡(luò)接口指針}inp;/* 上層回調(diào)函數(shù)消息 */struct {tcpip_callback_fn function; //回調(diào)函數(shù)void *ctx; //回調(diào)函數(shù)參數(shù)}cb;/* 定時(shí)事件 */struct {u32_t msecs; //時(shí)間sys_timeout_handler h; //回調(diào)函數(shù)void *arg; //回調(diào)函數(shù)參數(shù)}tmo;}msg; };

在看一下，內(nèi)核是怎么分類處理應(yīng)用層消息的

static tcpip_init_done_fn tcpip_init_done; static void *tcpip_init_done_arg; static sys_mbox_t mbox;/* tcp/ip線程 */ static void tcpip_thread(void *arg) {struct tcpip_msg *msg;/* 用戶自定義初始化函數(shù) */if(tcpip_init_done != NULL) {tcpip_init_done(tcpip_init_done_arg);}while(1) {/* 所有的超時(shí)事件和郵箱消息都在這里處理 */sys_timeouts_mbox_fetch(&mbox, (void **)&msg);/* 接收到消息 */switch(msg->type) {/* API消息 */case TCPIP_MSG_API:/* 調(diào)用API */msg->msg.apimsg->function(&(msg->msg.apimsg->msg));break;/* 底層數(shù)據(jù)包輸入 */case TCPIP_MSG_INPKT:/* 以太網(wǎng)設(shè)備 *//* 支持ARP協(xié)議 */if(msg->msg.inp.netif->flags & (NETIF_FLAG_ETHARP | NETIF_FLAG_ETHERNET)) {/* 以太網(wǎng)數(shù)據(jù)包輸入處理 */ethernet_input(msg->msg.inp.p, msg->msg.inp.netif);}/* 不支持ARP協(xié)議 */else{/* IP數(shù)據(jù)包輸入處理 */ip_input(msg->msg.inp.p, msg->msg.inp.netif);}/* 釋放該消息內(nèi)存空間 */memp_free(MEMP_TCPIP_MSG_INPKT, msg);break;/* 注冊(cè)一個(gè)定時(shí)事件 */case TCPIP_MSG_TIMEOUT:/* 啟動(dòng)定時(shí)事件 */sys_timeout(msg->msg.tmo.msecs, msg->msg.tmo.h, msg->msg.tmo.arg);/* 釋放該消息內(nèi)存空間 */memp_free(MEMP_TCPIP_MSG_API, msg);break;/* 刪除一個(gè)定時(shí)事件 */case TCPIP_MSG_UNTIMEOUT:/* 取消定時(shí)事件 */sys_untimeout(msg->msg.tmo.h, msg->msg.tmo.arg);/* 釋放該消息內(nèi)存空間 */memp_free(MEMP_TCPIP_MSG_API, msg);break;/* 上層回調(diào)函數(shù) */case TCPIP_MSG_CALLBACK:/* 調(diào)用回調(diào)函數(shù) */msg->msg.cb.function(msg->msg.cb.ctx);/* 釋放該消息內(nèi)存空間 */memp_free(MEMP_TCPIP_MSG_API, msg);break;/* 上層回調(diào)函數(shù)(消息為靜態(tài)) */case TCPIP_MSG_CALLBACK_STATIC:/* 調(diào)用回調(diào)函數(shù) */msg->msg.cb.function(msg->msg.cb.ctx);break;default:break;}} }/* 底層數(shù)據(jù)包輸入處理函數(shù) */ err_t tcpip_input(struct pbuf *p, struct netif *inp) {struct tcpip_msg *msg;/* 郵箱無(wú)效 */if(!sys_mbox_valid(&mbox)) {return ERR_VAL;}/* 為底層數(shù)據(jù)包輸入消息從內(nèi)存池申請(qǐng)內(nèi)存 */msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_INPKT);if(msg == NULL) {return ERR_MEM;}/* 底層數(shù)據(jù)包輸入消息 */msg->type = TCPIP_MSG_INPKT;/* 數(shù)據(jù)包內(nèi)容 */msg->msg.inp.p = p;/* 網(wǎng)絡(luò)接口指針 */msg->msg.inp.netif = inp;/* 發(fā)送消息 */if(sys_mbox_trypost(&mbox, msg) != ERR_OK) {memp_free(MEMP_TCPIP_MSG_INPKT, msg);return ERR_MEM;}return ERR_OK; }/* 上層回調(diào)函數(shù) */ err_t tcpip_callback_with_block(tcpip_callback_fn function, void *ctx, u8_t block) {struct tcpip_msg *msg;/* 郵箱有效 */if(sys_mbox_valid(&mbox)) {/* 為上層回調(diào)函數(shù)消息從內(nèi)存池申請(qǐng)內(nèi)存 */msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);if(msg == NULL) {return ERR_MEM;}/* 上層回調(diào)函數(shù) */msg->type = TCPIP_MSG_CALLBACK;/* 回調(diào)函數(shù) */msg->msg.cb.function = function;/* 回調(diào)函數(shù)參數(shù) */msg->msg.cb.ctx = ctx;/* 發(fā)送消息(阻塞) */if(block) {sys_mbox_post(&mbox, msg);}/* 發(fā)送消息(非阻塞) */else {if(sys_mbox_trypost(&mbox, msg) != ERR_OK) {memp_free(MEMP_TCPIP_MSG_API, msg);return ERR_MEM;}}return ERR_OK;}return ERR_VAL; }/* 注冊(cè)一個(gè)定時(shí)事件 */ err_t tcpip_timeout(u32_t msecs, sys_timeout_handler h, void *arg) {struct tcpip_msg *msg;/* 郵箱為有效 */if(sys_mbox_valid(&mbox)) {/* 為注冊(cè)一個(gè)定時(shí)事件消息從內(nèi)存池申請(qǐng)內(nèi)存 */msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);if(msg == NULL) {return ERR_MEM;}/* 注冊(cè)一個(gè)定時(shí)事件 */msg->type = TCPIP_MSG_TIMEOUT;/* 定時(shí)事件 */msg->msg.tmo.msecs = msecs;/* 回調(diào)函數(shù) */msg->msg.tmo.h = h;/* 回調(diào)函數(shù)參數(shù) */msg->msg.tmo.arg = arg;/* 發(fā)送消息 */sys_mbox_post(&mbox, msg);return ERR_OK;}return ERR_VAL; }/* 刪除一個(gè)定時(shí)事件 */ err_t tcpip_untimeout(sys_timeout_handler h, void *arg) {struct tcpip_msg *msg;/* 郵箱為有效 */if(sys_mbox_valid(&mbox)) {/* 為刪除一個(gè)定時(shí)事件消息從內(nèi)存池申請(qǐng)內(nèi)存 */msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);if(msg == NULL) {return ERR_MEM;}/* 刪除一個(gè)定時(shí)事件 */msg->type = TCPIP_MSG_UNTIMEOUT;/* 回調(diào)函數(shù) */msg->msg.tmo.h = h;/* 回調(diào)函數(shù)參數(shù) */msg->msg.tmo.arg = arg;/* 發(fā)送消息 */sys_mbox_post(&mbox, msg);return ERR_OK;}return ERR_VAL; }/* API調(diào)用 */ err_t tcpip_apimsg(struct api_msg *apimsg) {struct tcpip_msg msg;/* 郵箱為有效 */if(sys_mbox_valid(&mbox)) {/* 調(diào)用API */msg.type = TCPIP_MSG_API;/* API消息 */msg.msg.apimsg = apimsg;/* 發(fā)送消息 */sys_mbox_post(&mbox, &msg);/* 等待API調(diào)用完成 */sys_arch_sem_wait(&apimsg->msg.conn->op_completed, 0);return apimsg->msg.err;}return ERR_VAL; }/* 創(chuàng)建上層回調(diào)函數(shù)消息 */ struct tcpip_callback_msg *tcpip_callbackmsg_new(tcpip_callback_fn function, void *ctx) {/* 為上層回調(diào)函數(shù)消息從內(nèi)存池申請(qǐng)內(nèi)存 */struct tcpip_msg *msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_API);if(msg == NULL) {return NULL;}/* 上層回調(diào)函數(shù) */msg->type = TCPIP_MSG_CALLBACK_STATIC;/* 回調(diào)函數(shù) */msg->msg.cb.function = function;/* 回調(diào)函數(shù)參數(shù) */msg->msg.cb.ctx = ctx;/* 返回消息指針 */return (struct tcpip_callback_msg *)msg; }/* 釋放上層回調(diào)函數(shù)消息 */ void tcpip_callbackmsg_delete(struct tcpip_callback_msg* msg) {memp_free(MEMP_TCPIP_MSG_API, msg); }/* 發(fā)送上層回調(diào)函數(shù)消息 */ err_t tcpip_trycallback(struct tcpip_callback_msg* msg) {if(!sys_mbox_valid(&mbox)) {return ERR_VAL;}return sys_mbox_trypost(&mbox, msg); }/* tcp/ip初始化 */ void tcpip_init(tcpip_init_done_fn initfunc, void *arg) {/* 初始化協(xié)議棧 */lwip_init();/* 自定義初始化函數(shù) */tcpip_init_done = initfunc;tcpip_init_done_arg = arg;/* 創(chuàng)建郵箱 */if(sys_mbox_new(&mbox, TCPIP_MBOX_SIZE) != ERR_OK) {}/* 創(chuàng)建線程 */sys_thread_new(TCPIP_THREAD_NAME, tcpip_thread, NULL, TCPIP_THREAD_STACKSIZE, TCPIP_THREAD_PRIO); }/* 釋放pbuf上層回調(diào)函數(shù) */ static void pbuf_free_int(void *p) {struct pbuf *q = (struct pbuf *)p;pbuf_free(q); }/* 使用上層回調(diào)函數(shù)消息釋放pbuf */ err_t pbuf_free_callback(struct pbuf *p) {/* 使用上層回調(diào)函數(shù)消息釋放pbuf */return tcpip_callback_with_block(pbuf_free_int, p, 0); }/* 使用上層回調(diào)函數(shù)消息釋放到內(nèi)存堆 */ err_t mem_free_callback(void *m) {/* 使用上層回調(diào)函數(shù)消息釋放到內(nèi)存堆 */return tcpip_callback_with_block(mem_free, m, 0); }

接下來(lái)看一下內(nèi)核收到消息后具體是怎么工作的

/* API消息 */ struct api_msg_msg {/* 連接結(jié)構(gòu) */struct netconn *conn;/* 錯(cuò)誤 */err_t err;union {/* do_send時(shí)需要的參數(shù) */struct netbuf *b;/* do_newconn時(shí)需要的參數(shù) */struct {u8_t proto; //協(xié)議類型}n;/* do_bind和do_connect時(shí)需要的參數(shù) */struct {ip_addr_t *ipaddr; //IP地址u16_t port; //端口號(hào)}bc;/* do_getaddr時(shí)需要的參數(shù) */struct {ip_addr_t *ipaddr; //IP地址u16_t *port; //端口號(hào)u8_t local; //1本地IP、0遠(yuǎn)程IP}ad;/* do_write時(shí)需要的參數(shù) */struct {const void *dataptr; //數(shù)據(jù)size_t len; //長(zhǎng)度u8_t apiflags; //標(biāo)志位}w;/* do_recv時(shí)需要的參數(shù) */struct {u32_t len; //長(zhǎng)度}r;/* do_close時(shí)需要的參數(shù) */struct {u8_t shut; //關(guān)閉方向}sd;}msg; };/* API消息 */ struct api_msg {void (*function)(struct api_msg_msg *msg); //回調(diào)函數(shù)struct api_msg_msg msg; //回調(diào)函數(shù)參數(shù) }; /* 設(shè)置是否為阻塞態(tài) */ #define SET_NONBLOCKING_CONNECT(conn, val) do { if(val) { \(conn)->flags |= NETCONN_FLAG_IN_NONBLOCKING_CONNECT; \ } else { \(conn)->flags &= ~ NETCONN_FLAG_IN_NONBLOCKING_CONNECT; }} while(0) /* 非阻塞態(tài) */ #define IN_NONBLOCKING_CONNECT(conn) (((conn)->flags & NETCONN_FLAG_IN_NONBLOCKING_CONNECT) != 0)static err_t do_writemore(struct netconn *conn); static void do_close_internal(struct netconn *conn);/* 原始IP接口接收回調(diào)函數(shù) */ static u8_t recv_raw(void *arg, struct raw_pcb *pcb, struct pbuf *p, ip_addr_t *addr) {struct pbuf *q;struct netbuf *buf;struct netconn *conn;/* 參數(shù) */conn = (struct netconn *)arg;/* 接收郵箱有效 */if((conn != NULL) && sys_mbox_valid(&conn->recvmbox)) {/* 將數(shù)據(jù)放到netbuf中 */q = pbuf_alloc(PBUF_RAW, p->tot_len, PBUF_RAM);if(q != NULL) {if(pbuf_copy(q, p) != ERR_OK) {pbuf_free(q);q = NULL;}}if(q != NULL) {u16_t len;buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);if(buf == NULL) {pbuf_free(q);return 0;}buf->p = q;buf->ptr = q;ip_addr_copy(buf->addr, *ip_current_src_addr());buf->port = pcb->protocol;len = q->tot_len;/* 發(fā)送接收郵箱消息 */if(sys_mbox_trypost(&conn->recvmbox, buf) != ERR_OK) {netbuf_delete(buf);return 0;} else {/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);}}}return 0; }/* UDP接口接收回調(diào)函數(shù) */ static void recv_udp(void *arg, struct udp_pcb *pcb, struct pbuf *p, ip_addr_t *addr, u16_t port) {struct netbuf *buf;struct netconn *conn;u16_t len;conn = (struct netconn *)arg;/* 郵箱無(wú)效 */if((conn == NULL) || !sys_mbox_valid(&conn->recvmbox)) {pbuf_free(p);return;}/* 將數(shù)據(jù)放到netbuf中 */buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);if(buf == NULL) {pbuf_free(p);return;} else {buf->p = p;buf->ptr = p;ip_addr_set(&buf->addr, addr);buf->port = port;}len = p->tot_len;/* 發(fā)送接收郵箱消息 */if(sys_mbox_trypost(&conn->recvmbox, buf) != ERR_OK) {netbuf_delete(buf);return;} else {/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);} }/* 接收回調(diào)函數(shù) */ static err_t recv_tcp(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err) {struct netconn *conn;u16_t len;conn = (struct netconn *)arg;if(conn == NULL) {return ERR_VAL;}/* 郵箱無(wú)效 */if(!sys_mbox_valid(&conn->recvmbox)) {if(p != NULL) {tcp_recved(pcb, p->tot_len);pbuf_free(p);}return ERR_OK;}/* 設(shè)置致命錯(cuò)誤 */NETCONN_SET_SAFE_ERR(conn, err);if(p != NULL) {len = p->tot_len;} else {len = 0;}/* 發(fā)送接收郵箱消息 */if(sys_mbox_trypost(&conn->recvmbox, p) != ERR_OK) {return ERR_MEM;}else {/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVPLUS, len);}return ERR_OK; }/* poll回調(diào)函數(shù) */ static err_t poll_tcp(void *arg, struct tcp_pcb *pcb) {struct netconn *conn = (struct netconn *)arg;/* 正在發(fā)送數(shù)據(jù) */if(conn->state == NETCONN_WRITE) {do_writemore(conn);}/* 關(guān)閉狀態(tài) */else if(conn->state == NETCONN_CLOSE) {do_close_internal(conn);}/* 需要再次檢查是否可寫(xiě) */if(conn->flags & NETCONN_FLAG_CHECK_WRITESPACE) {/* 判斷是否可寫(xiě) */if((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&(tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);}}return ERR_OK; }/* 發(fā)送回調(diào)函數(shù) */ static err_t sent_tcp(void *arg, struct tcp_pcb *pcb, u16_t len) {struct netconn *conn = (struct netconn *)arg;/* 正在發(fā)送數(shù)據(jù) */if(conn->state == NETCONN_WRITE) {do_writemore(conn);} /* 關(guān)閉狀態(tài) */else if(conn->state == NETCONN_CLOSE) {do_close_internal(conn);}if(conn) {/* 需要再次檢查是否可寫(xiě) */if((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&(tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);}}return ERR_OK; }/* 錯(cuò)誤回調(diào)函數(shù) */ static void err_tcp(void *arg, err_t err) {struct netconn *conn;enum netconn_state old_state;conn = (struct netconn *)arg;conn->pcb.tcp = NULL;/* 記錄錯(cuò)誤 */conn->last_err = err;/* 復(fù)位連接 */old_state = conn->state;conn->state = NETCONN_NONE;/* 調(diào)用連接回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_ERROR, 0);API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);/* 發(fā)送接收郵箱消息 */if(sys_mbox_valid(&conn->recvmbox)) {sys_mbox_trypost(&conn->recvmbox, NULL);}/* 發(fā)送接受連接郵箱消息 */if(sys_mbox_valid(&conn->acceptmbox)) {sys_mbox_trypost(&conn->acceptmbox, NULL);}if((old_state == NETCONN_WRITE) || (old_state == NETCONN_CLOSE) ||(old_state == NETCONN_CONNECT)) {/* 清空阻塞態(tài) */int was_nonblocking_connect = IN_NONBLOCKING_CONNECT(conn);SET_NONBLOCKING_CONNECT(conn, 0);/* 阻塞態(tài) */if(!was_nonblocking_connect) {conn->current_msg->err = err;conn->current_msg = NULL;/* 釋放操作完成信號(hào)量 */sys_sem_signal(&conn->op_completed);}} }/* 設(shè)置TCP回調(diào)函數(shù) */ static void setup_tcp(struct netconn *conn) {struct tcp_pcb *pcb;pcb = conn->pcb.tcp;/* 設(shè)置用戶自定義參數(shù) */ tcp_arg(pcb, conn);/* 設(shè)置接收回調(diào)函數(shù) */ tcp_recv(pcb, recv_tcp);/* 設(shè)置發(fā)送成功回調(diào)函數(shù) */tcp_sent(pcb, sent_tcp);/* 設(shè)置poll回調(diào)函數(shù)和周期 */tcp_poll(pcb, poll_tcp, 4);/* 設(shè)置連接錯(cuò)誤回調(diào)函數(shù) */ tcp_err(pcb, err_tcp); }/* 接受連接回調(diào)函數(shù) */ static err_t accept_function(void *arg, struct tcp_pcb *newpcb, err_t err) {struct netconn *newconn;struct netconn *conn = (struct netconn *)arg;if(!sys_mbox_valid(&conn->acceptmbox)) {return ERR_VAL;}/* 為新連接創(chuàng)建一個(gè)連接結(jié)構(gòu)體，設(shè)置TCP回調(diào)函數(shù) */newconn = netconn_alloc(conn->type, conn->callback);if(newconn == NULL) {return ERR_MEM;}newconn->pcb.tcp = newpcb;setup_tcp(newconn);newconn->last_err = err;/* 發(fā)送接受連接消息 */if(sys_mbox_trypost(&conn->acceptmbox, newconn) != ERR_OK) {struct tcp_pcb* pcb = newconn->pcb.tcp;tcp_arg(pcb, NULL);tcp_recv(pcb, NULL);tcp_sent(pcb, NULL);tcp_poll(pcb, NULL, 4);tcp_err(pcb, NULL);newconn->pcb.tcp = NULL;sys_mbox_free(&newconn->recvmbox);sys_mbox_set_invalid(&newconn->recvmbox);netconn_free(newconn);return ERR_MEM;} else {/* 調(diào)用連接事件回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);}return ERR_OK; }/* 創(chuàng)建控制塊 */ static void pcb_new(struct api_msg_msg *msg) {LWIP_ASSERT("pcb_new: pcb already allocated", msg->conn->pcb.tcp == NULL);/* 判斷協(xié)議類型 */switch(NETCONNTYPE_GROUP(msg->conn->type)) {/* 原始IP連接 */case NETCONN_RAW:/* 創(chuàng)建IP原始接口控制塊 */msg->conn->pcb.raw = raw_new(msg->msg.n.proto);if(msg->conn->pcb.raw == NULL) {msg->err = ERR_MEM;break;}/* IP原始接口設(shè)置接收回調(diào)函數(shù) */raw_recv(msg->conn->pcb.raw, recv_raw, msg->conn);break;/* UDP */case NETCONN_UDP:/* 創(chuàng)建一個(gè)UDP控制塊 */msg->conn->pcb.udp = udp_new();if(msg->conn->pcb.udp == NULL) {msg->err = ERR_MEM;break;}/* 無(wú)校驗(yàn)UDP */if(msg->conn->type == NETCONN_UDPNOCHKSUM) {udp_setflags(msg->conn->pcb.udp, UDP_FLAGS_NOCHKSUM);}/* 設(shè)置UDP控制塊回調(diào)函數(shù) */udp_recv(msg->conn->pcb.udp, recv_udp, msg->conn);break;/* TCP */case NETCONN_TCP:/* 新建TCP控制塊 */msg->conn->pcb.tcp = tcp_new();if(msg->conn->pcb.tcp == NULL) {msg->err = ERR_MEM;break;}/* 設(shè)置TCP回調(diào)函數(shù) */setup_tcp(msg->conn);break;/* 不支持 */default:msg->err = ERR_VAL;break;} }/* 創(chuàng)建一個(gè)連接PCB */ void do_newconn(struct api_msg_msg *msg) {msg->err = ERR_OK;/* 控制塊還未創(chuàng)建 */if(msg->conn->pcb.tcp == NULL) {/* 創(chuàng)建控制塊 */pcb_new(msg);}/* 釋放API調(diào)用完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 創(chuàng)建一個(gè)連接結(jié)構(gòu)體 */ struct netconn *netconn_alloc(enum netconn_type t, netconn_callback callback) {struct netconn *conn;int size;/* 為連接申請(qǐng)內(nèi)存空間 */conn = (struct netconn *)memp_malloc(MEMP_NETCONN);if(conn == NULL) {return NULL;}/* 清空最近一個(gè)錯(cuò)誤 */conn->last_err = ERR_OK;/* 連接類型 */conn->type = t;/* 清空控制塊指針 */conn->pcb.tcp = NULL;size = DEFAULT_RAW_RECVMBOX_SIZE;/* 創(chuàng)建API調(diào)用完成信號(hào)量 */if(sys_sem_new(&conn->op_completed, 0) != ERR_OK) {goto free_and_return;}/* 創(chuàng)建接收郵箱 */if(sys_mbox_new(&conn->recvmbox, size) != ERR_OK) {sys_sem_free(&conn->op_completed);goto free_and_return;}/* 接受連接郵箱設(shè)置為無(wú)效 */ sys_mbox_set_invalid(&conn->acceptmbox);/* 不處于任何連接狀態(tài) */conn->state = NETCONN_NONE;/* 套接字描述符 */conn->socket = -1;/* 回調(diào)函數(shù) */conn->callback = callback;/* 寫(xiě)數(shù)據(jù)緩存不足時(shí)，數(shù)據(jù)暫時(shí)封裝在current_msg中，write_offset是下一次發(fā)送的索引 */conn->current_msg = NULL;conn->write_offset = 0;/* 清空標(biāo)志位 */conn->flags = 0;return conn;free_and_return:memp_free(MEMP_NETCONN, conn);return NULL; }/* 釋放連接結(jié)構(gòu)體 */ void netconn_free(struct netconn *conn) {/* 刪除API調(diào)用完成信號(hào)量 */sys_sem_free(&conn->op_completed);/* API信號(hào)量設(shè)置為無(wú)效 */ sys_sem_set_invalid(&conn->op_completed);/* 釋放連接內(nèi)存空間 */memp_free(MEMP_NETCONN, conn); }/* 刪除接收郵箱和接受連接郵箱 */ static void netconn_drain(struct netconn *conn) {void *mem;struct pbuf *p;/* 接收郵箱有效 */if(sys_mbox_valid(&conn->recvmbox)) {/* 接收消息并處理 */while(sys_mbox_tryfetch(&conn->recvmbox, &mem) != SYS_MBOX_EMPTY) {/* TCP連接 */if(conn->type == NETCONN_TCP) {/* pbuf處理 */if(mem != NULL) {p = (struct pbuf *)mem;if(conn->pcb.tcp != NULL) {/* 應(yīng)用層接收對(duì)方傳來(lái)的數(shù)據(jù) */tcp_recved(conn->pcb.tcp, p->tot_len);}/* 釋放數(shù)據(jù)pbuf */pbuf_free(p);}}else{/* 刪除netbuf */netbuf_delete((struct netbuf *)mem);}}/* 刪除接收郵箱 */sys_mbox_free(&conn->recvmbox);sys_mbox_set_invalid(&conn->recvmbox);}/* 接受連接郵箱有效 */if(sys_mbox_valid(&conn->acceptmbox)) {/* 接收消息并處理 */while(sys_mbox_tryfetch(&conn->acceptmbox, &mem) != SYS_MBOX_EMPTY) {/* 新連接處理 */struct netconn *newconn = (struct netconn *)mem;if(conn->pcb.tcp != NULL) {/* 接受新連接 */tcp_accepted(conn->pcb.tcp);}/* 刪除每一個(gè)新連接接收郵箱 */netconn_drain(newconn);/* 刪除TCP控制塊，并發(fā)送TCP復(fù)位報(bào)文 */if(newconn->pcb.tcp != NULL) {tcp_abort(newconn->pcb.tcp);newconn->pcb.tcp = NULL;}/* 釋放連接結(jié)構(gòu)體 */netconn_free(newconn);}/* 刪除接受連接郵箱 */sys_mbox_free(&conn->acceptmbox);sys_mbox_set_invalid(&conn->acceptmbox);} }/* 關(guān)閉連接 */ static void do_close_internal(struct netconn *conn) {err_t err;u8_t shut, shut_rx, shut_tx, close;/* 關(guān)閉方向 */shut = conn->current_msg->msg.sd.shut;shut_rx = shut & NETCONN_SHUT_RD;shut_tx = shut & NETCONN_SHUT_WR;/* 關(guān)閉 */close = shut == NETCONN_SHUT_RDWR;/* 清空用戶自定義參數(shù) */ if(close) {tcp_arg(conn->pcb.tcp, NULL);}/* 偵聽(tīng)狀態(tài)，清空接受連接回調(diào)函數(shù) */if(conn->pcb.tcp->state == LISTEN) {tcp_accept(conn->pcb.tcp, NULL);} /* 非偵聽(tīng)狀態(tài) */else{/* 關(guān)閉接收方向，清空接收和接受連接回調(diào)函數(shù) */if(shut_rx) {tcp_recv(conn->pcb.tcp, NULL);tcp_accept(conn->pcb.tcp, NULL);}/* 關(guān)閉發(fā)送方向，清空發(fā)送回調(diào)函數(shù) */if(shut_tx) {tcp_sent(conn->pcb.tcp, NULL);}/* 清空poll和錯(cuò)誤回調(diào)函數(shù) */if(close) {tcp_poll(conn->pcb.tcp, NULL, 4);tcp_err(conn->pcb.tcp, NULL);}}/* 關(guān)閉連接 */if(close) {err = tcp_close(conn->pcb.tcp);} else {err = tcp_shutdown(conn->pcb.tcp, shut_rx, shut_tx);}/* 調(diào)用連接API回調(diào)函數(shù) */if(err == ERR_OK) {conn->current_msg->err = ERR_OK;conn->current_msg = NULL;conn->state = NETCONN_NONE;if(close) {conn->pcb.tcp = NULL;API_EVENT(conn, NETCONN_EVT_ERROR, 0);}if(shut_rx) {API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);}if(shut_tx) {API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);}sys_sem_signal(&conn->op_completed);}/* 關(guān)閉失敗 */else {tcp_sent(conn->pcb.tcp, sent_tcp);tcp_poll(conn->pcb.tcp, poll_tcp, 4);tcp_err(conn->pcb.tcp, err_tcp);tcp_arg(conn->pcb.tcp, conn);} }/* 刪除控制塊 */ void do_delconn(struct api_msg_msg *msg) {if((msg->conn->state != NETCONN_NONE) && (msg->conn->state != NETCONN_LISTEN) && (msg->conn->state != NETCONN_CONNECT)) {msg->err = ERR_INPROGRESS;} else {/* 刪除接收郵箱和接受連接郵箱 */netconn_drain(msg->conn);/* 判斷連接類型 */if(msg->conn->pcb.tcp != NULL) {switch(NETCONNTYPE_GROUP(msg->conn->type)) {/* 原始IP連接 */case NETCONN_RAW:/* 移除IP原始接口控制塊 */raw_remove(msg->conn->pcb.raw);break;/* UDP */case NETCONN_UDP:/* 刪除UDP控制塊 */msg->conn->pcb.udp->recv_arg = NULL;udp_remove(msg->conn->pcb.udp);break;/* TCP */case NETCONN_TCP:msg->conn->state = NETCONN_CLOSE;msg->msg.sd.shut = NETCONN_SHUT_RDWR;msg->conn->current_msg = msg;/* 關(guān)閉連接 */do_close_internal(msg->conn);return;default:break;}msg->conn->pcb.tcp = NULL;}/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(msg->conn, NETCONN_EVT_RCVPLUS, 0);API_EVENT(msg->conn, NETCONN_EVT_SENDPLUS, 0);}/* 釋放操作完成信號(hào)量 */if(sys_sem_valid(&msg->conn->op_completed)) {sys_sem_signal(&msg->conn->op_completed);} }/* 綁定本地端口 */ void do_bind(struct api_msg_msg *msg) {/* 根據(jù)連接類型調(diào)用綁定 */if(ERR_IS_FATAL(msg->conn->last_err)) {msg->err = msg->conn->last_err;} else {msg->err = ERR_VAL;if(msg->conn->pcb.tcp != NULL) {switch(NETCONNTYPE_GROUP(msg->conn->type)) {case NETCONN_RAW:msg->err = raw_bind(msg->conn->pcb.raw, msg->msg.bc.ipaddr);break;case NETCONN_UDP:msg->err = udp_bind(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);break;case NETCONN_TCP:msg->err = tcp_bind(msg->conn->pcb.tcp, msg->msg.bc.ipaddr, msg->msg.bc.port);break;default:break;}}}/* 釋放API調(diào)用完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 連接完成 */ static err_t do_connected(void *arg, struct tcp_pcb *pcb, err_t err) {struct netconn *conn;int was_blocking;conn = (struct netconn *)arg;if(conn == NULL) {return ERR_VAL;}if(conn->current_msg != NULL) {conn->current_msg->err = err;}/* 設(shè)置TCP回調(diào)函數(shù) */if((conn->type == NETCONN_TCP) && (err == ERR_OK)){setup_tcp(conn);}/* 是否為阻塞態(tài) */was_blocking = !IN_NONBLOCKING_CONNECT(conn);/* 清空非阻塞態(tài) */SET_NONBLOCKING_CONNECT(conn, 0);/* 清空消息 */conn->current_msg = NULL;/* 清空狀態(tài) */conn->state = NETCONN_NONE;if(!was_blocking) {NETCONN_SET_SAFE_ERR(conn, ERR_OK);}/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);/* 阻塞態(tài)，釋放操作完成信號(hào)量 */if(was_blocking) {sys_sem_signal(&conn->op_completed);}return ERR_OK; }/* 連接遠(yuǎn)程端口 */ void do_connect(struct api_msg_msg *msg) {/* 根據(jù)連接類型調(diào)用連接 */if(msg->conn->pcb.tcp == NULL) {msg->err = ERR_CLSD;} else {switch(NETCONNTYPE_GROUP(msg->conn->type)) {case NETCONN_RAW:msg->err = raw_connect(msg->conn->pcb.raw, msg->msg.bc.ipaddr);break;case NETCONN_UDP:msg->err = udp_connect(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);break;case NETCONN_TCP:if(msg->conn->state != NETCONN_NONE) {msg->err = ERR_ISCONN;} else {setup_tcp(msg->conn);msg->err = tcp_connect(msg->conn->pcb.tcp, msg->msg.bc.ipaddr, msg->msg.bc.port, do_connected);if(msg->err == ERR_OK) {u8_t non_blocking = netconn_is_nonblocking(msg->conn);msg->conn->state = NETCONN_CONNECT;SET_NONBLOCKING_CONNECT(msg->conn, non_blocking);if(non_blocking) {msg->err = ERR_INPROGRESS;} else {msg->conn->current_msg = msg;return;}}}break;default:break;}}/* 釋放操作完成信號(hào)量 */sys_sem_signal(&msg->conn->op_completed); }/* 斷開(kāi)連接 */ void do_disconnect(struct api_msg_msg *msg) {if(NETCONNTYPE_GROUP(msg->conn->type) == NETCONN_UDP) {udp_disconnect(msg->conn->pcb.udp);msg->err = ERR_OK;} else{msg->err = ERR_VAL;}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 偵聽(tīng) */ void do_listen(struct api_msg_msg *msg) {if(ERR_IS_FATAL(msg->conn->last_err)) {msg->err = msg->conn->last_err;} else {msg->err = ERR_CONN;if(msg->conn->pcb.tcp != NULL) {if(msg->conn->type == NETCONN_TCP) {if(msg->conn->state == NETCONN_NONE) {struct tcp_pcb *lpcb = tcp_listen(msg->conn->pcb.tcp);/* 刪除接收郵箱，創(chuàng)建接受連接郵箱 */if(lpcb == NULL) {msg->err = ERR_MEM;}else {if(sys_mbox_valid(&msg->conn->recvmbox)) {sys_mbox_free(&msg->conn->recvmbox);sys_mbox_set_invalid(&msg->conn->recvmbox);}msg->err = ERR_OK;if(!sys_mbox_valid(&msg->conn->acceptmbox)) {msg->err = sys_mbox_new(&msg->conn->acceptmbox, DEFAULT_ACCEPTMBOX_SIZE);}if(msg->err == ERR_OK) {msg->conn->state = NETCONN_LISTEN;msg->conn->pcb.tcp = lpcb;tcp_arg(msg->conn->pcb.tcp, msg->conn);tcp_accept(msg->conn->pcb.tcp, accept_function);} else {tcp_close(lpcb);msg->conn->pcb.tcp = NULL;}}}} else {msg->err = ERR_ARG;}}}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 非TCP發(fā)送數(shù)據(jù) */ void do_send(struct api_msg_msg *msg) {if(ERR_IS_FATAL(msg->conn->last_err)) {msg->err = msg->conn->last_err;} else {msg->err = ERR_CONN;if(msg->conn->pcb.tcp != NULL) {switch(NETCONNTYPE_GROUP(msg->conn->type)) {case NETCONN_RAW:if(ip_addr_isany(&msg->msg.b->addr)) {msg->err = raw_send(msg->conn->pcb.raw, msg->msg.b->p);} else {msg->err = raw_sendto(msg->conn->pcb.raw, msg->msg.b->p, &msg->msg.b->addr);}break;case NETCONN_UDP:if(ip_addr_isany(&msg->msg.b->addr)) {msg->err = udp_send(msg->conn->pcb.udp, msg->msg.b->p);} else {msg->err = udp_sendto(msg->conn->pcb.udp, msg->msg.b->p, &msg->msg.b->addr, msg->msg.b->port);}break;default:break;}}}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }#if LWIP_TCP /* TCP接收數(shù)據(jù) */ void do_recv(struct api_msg_msg *msg) {msg->err = ERR_OK;if(msg->conn->pcb.tcp != NULL) {if(msg->conn->type == NETCONN_TCP) {u32_t remaining = msg->msg.r.len;do {u16_t recved = (remaining > 0xffff) ? 0xffff : (u16_t)remaining;tcp_recved(msg->conn->pcb.tcp, recved);remaining -= recved;}while(remaining != 0);}}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* TCP發(fā)送沒(méi)發(fā)完的數(shù)據(jù) */ static err_t do_writemore(struct netconn *conn) {err_t err;void *dataptr;u16_t len, available;u8_t write_finished = 0;size_t diff;u8_t dontblock = netconn_is_nonblocking(conn) || (conn->current_msg->msg.w.apiflags & NETCONN_DONTBLOCK);u8_t apiflags = conn->current_msg->msg.w.apiflags;{/* 判斷一次能不能寫(xiě)完 */dataptr = (u8_t*)conn->current_msg->msg.w.dataptr + conn->write_offset;diff = conn->current_msg->msg.w.len - conn->write_offset;if(diff > 0xffffUL) {len = 0xffff;apiflags |= TCP_WRITE_FLAG_MORE;} else {len = (u16_t)diff;}available = tcp_sndbuf(conn->pcb.tcp);/* 寫(xiě)不完 */if(available < len) {len = available;/* 非阻塞，報(bào)錯(cuò) */if(dontblock){if(!len) {err = ERR_WOULDBLOCK;goto err_mem;}} /* 阻塞，還有剩余數(shù)據(jù) */else {apiflags |= TCP_WRITE_FLAG_MORE;}}/* 組建發(fā)送數(shù)據(jù) */err = tcp_write(conn->pcb.tcp, dataptr, len, apiflags);if((err == ERR_OK) || (err == ERR_MEM)) { err_mem:/* 非阻塞態(tài)，并且沒(méi)寫(xiě)完 */if(dontblock && (len < conn->current_msg->msg.w.len)) {/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_SENDMINUS, len);/* 需要再次檢查是否可寫(xiě) */conn->flags |= NETCONN_FLAG_CHECK_WRITESPACE;} /* 發(fā)送數(shù)據(jù)成功 */else if((tcp_sndbuf(conn->pcb.tcp) <= TCP_SNDLOWAT) || (tcp_sndqueuelen(conn->pcb.tcp) >= TCP_SNDQUEUELOWAT)) {/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_SENDMINUS, len);}}/* 將數(shù)據(jù)發(fā)送出去 */if(err == ERR_OK) {conn->write_offset += len;if((conn->write_offset == conn->current_msg->msg.w.len) || dontblock) {conn->current_msg->msg.w.len = conn->write_offset;write_finished = 1;conn->write_offset = 0;}tcp_output(conn->pcb.tcp);} else if((err == ERR_MEM) && !dontblock) {tcp_output(conn->pcb.tcp);} else {write_finished = 1;conn->current_msg->msg.w.len = 0;}}/* 發(fā)送完成 */if(write_finished) {conn->current_msg->err = err;conn->current_msg = NULL;conn->state = NETCONN_NONE;{/* 釋放操作完成信號(hào)量 */sys_sem_signal(&conn->op_completed);}}return ERR_OK; }/* TCP發(fā)送數(shù)據(jù) */ void do_write(struct api_msg_msg *msg) {if(ERR_IS_FATAL(msg->conn->last_err)) {msg->err = msg->conn->last_err;} else {/* TCP連接 */if(msg->conn->type == NETCONN_TCP) {if(msg->conn->state != NETCONN_NONE) {msg->err = ERR_INPROGRESS;}else if(msg->conn->pcb.tcp != NULL) {msg->conn->state = NETCONN_WRITE;msg->conn->current_msg = msg;msg->conn->write_offset = 0;do_writemore(msg->conn);return;} else {msg->err = ERR_CONN;}} /* 非TCP連接 */else {msg->err = ERR_VAL;}}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 獲取本地或者遠(yuǎn)程IP和端口號(hào) */ void do_getaddr(struct api_msg_msg *msg) {if(msg->conn->pcb.ip != NULL) {*(msg->msg.ad.ipaddr) = (msg->msg.ad.local ? msg->conn->pcb.ip->local_ip : msg->conn->pcb.ip->remote_ip);msg->err = ERR_OK;switch(NETCONNTYPE_GROUP(msg->conn->type)) {case NETCONN_RAW:if(msg->msg.ad.local) {*(msg->msg.ad.port) = msg->conn->pcb.raw->protocol;} else {msg->err = ERR_CONN;}break;case NETCONN_UDP:if(msg->msg.ad.local) {*(msg->msg.ad.port) = msg->conn->pcb.udp->local_port;} else {if((msg->conn->pcb.udp->flags & UDP_FLAGS_CONNECTED) == 0) {msg->err = ERR_CONN;} else {*(msg->msg.ad.port) = msg->conn->pcb.udp->remote_port;}}break;case NETCONN_TCP:*(msg->msg.ad.port) = (msg->msg.ad.local ? msg->conn->pcb.tcp->local_port : msg->conn->pcb.tcp->remote_port);break;default:break;}} else {msg->err = ERR_CONN;}/* 釋放操作完成信號(hào)量 */TCPIP_APIMSG_ACK(msg); }/* 關(guān)閉連接 */ void do_close(struct api_msg_msg *msg) {if((msg->conn->state != NETCONN_NONE) && (msg->conn->state != NETCONN_LISTEN)) {msg->err = ERR_INPROGRESS;} /* TCP連接 */else if((msg->conn->pcb.tcp != NULL) && (msg->conn->type == NETCONN_TCP)) {if((msg->msg.sd.shut != NETCONN_SHUT_RDWR) && (msg->conn->state == NETCONN_LISTEN)) {msg->err = ERR_CONN;} else {/* 關(guān)閉接收方向 */if(msg->msg.sd.shut & NETCONN_SHUT_RD) {/* 刪除接收郵箱和接受連接郵箱 */netconn_drain(msg->conn);}msg->conn->state = NETCONN_CLOSE;msg->conn->current_msg = msg;/* 關(guān)閉連接 */do_close_internal(msg->conn);return;}} else{msg->err = ERR_VAL;}/* 釋放操作完成信號(hào)量 */sys_sem_signal(&msg->conn->op_completed); }

最后，看一下應(yīng)用程序接口

/* 創(chuàng)建一個(gè)新的連接并且設(shè)置回調(diào)函數(shù) */ struct netconn *netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_callback callback) {struct netconn *conn;struct api_msg msg;/* 創(chuàng)建一個(gè)連接結(jié)構(gòu)體 */conn = netconn_alloc(t, callback);if(conn != NULL) {/* 請(qǐng)求創(chuàng)建一個(gè)連接PCB */msg.function = do_newconn;msg.msg.msg.n.proto = proto;msg.msg.conn = conn;if(TCPIP_APIMSG(&msg) != ERR_OK) {sys_sem_free(&conn->op_completed);sys_mbox_free(&conn->recvmbox);memp_free(MEMP_NETCONN, conn);return NULL;}}return conn; }/* 刪除連接 */ err_t netconn_delete(struct netconn *conn) {struct api_msg msg;if(conn == NULL) {return ERR_OK;}/* 請(qǐng)求刪除控制塊 */msg.function = do_delconn;msg.msg.conn = conn;tcpip_apimsg(&msg);/* 釋放連接結(jié)構(gòu)體 */netconn_free(conn);return ERR_OK; }/* 獲取本地或者遠(yuǎn)程IP和端口號(hào) */ err_t netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local) {struct api_msg msg;err_t err;/* 請(qǐng)求獲取本地或者遠(yuǎn)程IP和端口號(hào) */msg.function = do_getaddr;msg.msg.conn = conn;msg.msg.msg.ad.ipaddr = addr;msg.msg.msg.ad.port = port;msg.msg.msg.ad.local = local;err = TCPIP_APIMSG(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 綁定本地端口 */ err_t netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port) {struct api_msg msg;err_t err;/* 請(qǐng)求綁定本地端口 */msg.function = do_bind;msg.msg.conn = conn;msg.msg.msg.bc.ipaddr = addr;msg.msg.msg.bc.port = port;err = TCPIP_APIMSG(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 連接遠(yuǎn)程端口 */ err_t netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port) {struct api_msg msg;err_t err;/* 請(qǐng)求連接遠(yuǎn)程端口 */msg.function = do_connect;msg.msg.conn = conn;msg.msg.msg.bc.ipaddr = addr;msg.msg.msg.bc.port = port;err = tcpip_apimsg(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 斷開(kāi)連接 */ err_t netconn_disconnect(struct netconn *conn) {struct api_msg msg;err_t err;/* 請(qǐng)求斷開(kāi)連接 */msg.function = do_disconnect;msg.msg.conn = conn;err = TCPIP_APIMSG(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 開(kāi)始偵聽(tīng) */ err_t netconn_listen_with_backlog(struct netconn *conn, u8_t backlog) {struct api_msg msg;err_t err;/* 請(qǐng)求偵聽(tīng) */msg.function = do_listen;msg.msg.conn = conn;err = TCPIP_APIMSG(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 接受連接 */ err_t netconn_accept(struct netconn *conn, struct netconn **new_conn) {struct netconn *newconn;err_t err;*new_conn = NULL;err = conn->last_err;if (ERR_IS_FATAL(err)) {return err;}/* 等待連接 */sys_arch_mbox_fetch(&conn->acceptmbox, (void **)&newconn, 0);/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);if(newconn == NULL) {NETCONN_SET_SAFE_ERR(conn, ERR_ABRT);return ERR_ABRT;}*new_conn = newconn;return ERR_OK; }/* 接收數(shù)據(jù) */ static err_t netconn_recv_data(struct netconn *conn, void **new_buf) {void *buf = NULL;u16_t len;err_t err;struct api_msg msg;*new_buf = NULL;err = conn->last_err;if(ERR_IS_FATAL(err)) {return err;}/* 等待數(shù)據(jù) */sys_arch_mbox_fetch(&conn->recvmbox, &buf, 0);/* TCP */if(conn->type == NETCONN_TCP){/* 自動(dòng)接收 */if(!netconn_get_noautorecved(conn) || (buf == NULL)) {/* 請(qǐng)求接收，更新窗口 */msg.function = do_recv;msg.msg.conn = conn;if(buf != NULL) {msg.msg.msg.r.len = ((struct pbuf *)buf)->tot_len;} else {msg.msg.msg.r.len = 1;}TCPIP_APIMSG(&msg);}if(buf == NULL) {API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);NETCONN_SET_SAFE_ERR(conn, ERR_CLSD);return ERR_CLSD;}len = ((struct pbuf *)buf)->tot_len;}/* 非TCP */else{len = netbuf_len((struct netbuf *)buf);}/* 調(diào)用連接API回調(diào)函數(shù) */API_EVENT(conn, NETCONN_EVT_RCVMINUS, len);*new_buf = buf;return ERR_OK; }/* 接收數(shù)據(jù) */ err_t netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf) {return netconn_recv_data(conn, (void **)new_buf); }/* 接收數(shù)據(jù)并將數(shù)據(jù)封裝到netbuf */ err_t netconn_recv(struct netconn *conn, struct netbuf **new_buf) {struct netbuf *buf = NULL;err_t err;*new_buf = NULL;if (conn->type == NETCONN_TCP){struct pbuf *p = NULL;buf = (struct netbuf *)memp_malloc(MEMP_NETBUF);if(buf == NULL) {NETCONN_SET_SAFE_ERR(conn, ERR_MEM);return ERR_MEM;}err = netconn_recv_data(conn, (void **)&p);if(err != ERR_OK) {memp_free(MEMP_NETBUF, buf);return err;}buf->p = p;buf->ptr = p;buf->port = 0;ip_addr_set_any(&buf->addr);*new_buf = buf;return ERR_OK;}else{return netconn_recv_data(conn, (void **)new_buf);} }/* 更新接收窗口 */ void netconn_recved(struct netconn *conn, u32_t length) {if((conn != NULL) && (conn->type == NETCONN_TCP) && (netconn_get_noautorecved(conn))) {struct api_msg msg;/* 請(qǐng)求接收，更新窗口 */msg.function = do_recv;msg.msg.conn = conn;msg.msg.msg.r.len = length;TCPIP_APIMSG(&msg);} }/* UDP或RAW發(fā)送數(shù)據(jù) */ err_t netconn_sendto(struct netconn *conn, struct netbuf *buf, ip_addr_t *addr, u16_t port) {if(buf != NULL) {ip_addr_set(&buf->addr, addr);buf->port = port;return netconn_send(conn, buf);}return ERR_VAL; }/* UDP或RAW發(fā)送數(shù)據(jù) */ err_t netconn_send(struct netconn *conn, struct netbuf *buf) {struct api_msg msg;err_t err;/* 請(qǐng)求發(fā)送數(shù)據(jù) */msg.function = do_send;msg.msg.conn = conn;msg.msg.msg.b = buf;err = TCPIP_APIMSG(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* TCP發(fā)送數(shù)據(jù) */ err_t netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size, u8_t apiflags, size_t *bytes_written) {struct api_msg msg;err_t err;u8_t dontblock;if(size == 0) {return ERR_OK;}dontblock = netconn_is_nonblocking(conn) || (apiflags & NETCONN_DONTBLOCK);if(dontblock && !bytes_written) {return ERR_VAL;}/* 請(qǐng)求TCP發(fā)送數(shù)據(jù) */msg.function = do_write;msg.msg.conn = conn;msg.msg.msg.w.dataptr = dataptr;msg.msg.msg.w.apiflags = apiflags;msg.msg.msg.w.len = size;err = TCPIP_APIMSG(&msg);if((err == ERR_OK) && (bytes_written != NULL)) {/* 非阻塞 */if(dontblock) {*bytes_written = msg.msg.msg.w.len;} /* 阻塞型 */else {*bytes_written = size;}}NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 關(guān)閉連接 */ static err_t netconn_close_shutdown(struct netconn *conn, u8_t how) {struct api_msg msg;err_t err;/* 請(qǐng)求關(guān)閉連接 */msg.function = do_close;msg.msg.conn = conn;msg.msg.msg.sd.shut = how;err = tcpip_apimsg(&msg);NETCONN_SET_SAFE_ERR(conn, err);return err; }/* 完全關(guān)閉連接 */ err_t netconn_close(struct netconn *conn) {return netconn_close_shutdown(conn, NETCONN_SHUT_RDWR); }/* 關(guān)閉連接方向 */ err_t netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx) {return netconn_close_shutdown(conn, (shut_rx ? NETCONN_SHUT_RD : 0) | (shut_tx ? NETCONN_SHUT_WR : 0)); }

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