前言

物聯(lián)網(wǎng)的IPV6應(yīng)用是一個(gè)趨勢，contiki是集成了6lowpan的一個(gè)集成開發(fā)工具。uip是集成在內(nèi)部的，支持IPV6以及IPV4，這里先通過IPV4與平臺(tái)連接建立一個(gè)數(shù)據(jù)通道。后續(xù)會(huì)跟進(jìn)IPV6以及6lowpan的應(yīng)用。而且uip不需要OS支持，以事件驅(qū)動(dòng)的方式編程，占用的RAM以及ROM都符合嵌入式的需求。

之前我們需要了解一些背景知識(shí)：

1，http的相關(guān)知識(shí)

2，yeelink http請求格式分析?（分析很透徹）

3，tcp/ip的連接

4，stm32平臺(tái)+enc28j60網(wǎng)絡(luò)模塊

5，uip1.0 （contiki里面的uip已經(jīng)是與6lowpan、ipv6耦合起來了，所以這里選擇了uip1.0的版本）uip0.9 refman中文翻譯?也是一個(gè)不錯(cuò)的博文，讓大家更快熟悉uip的編程思想。

移植

這一部分我們會(huì)先介紹uip在stm32平臺(tái)上的移植工作。Enc28j60是帶SPI 接口的獨(dú)立以太網(wǎng)控制器，可以用mcu控制spi來實(shí)現(xiàn)tcp/ip數(shù)據(jù)流的收發(fā)，所以要先完成Enc28j60的驅(qū)動(dòng)程序，再整合Uip。

這一部分可以參考：uip在stm32上的移植，說明的也很詳細(xì)，我就不累贅了。

軟件實(shí)現(xiàn)

1，DNS

uip自帶了一個(gè)dns的解析，配置如下：

<span class="hljs-function" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; background: transparent;"><span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span> <span class="hljs-title" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(25, 70, 157); background: transparent;">yeelink_init</span><span class="hljs-params" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 0, 255); background: transparent;">(<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span>)</span> </span>{uip_ipaddr_t ipaddr;resolv_init();uip_ipaddr(ipaddr, <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">221</span>, <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">228</span>, <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">255</span>, <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">1</span>); <span class="hljs-comment" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: italic; font-family: inherit; vertical-align: baseline; color: rgb(64, 128, 128); background: transparent;">// DNS</span>resolv_conf(ipaddr);resolv_query(YEELINK_HOST); } 這里的DNS我們可以通過查看自己的網(wǎng)絡(luò)參數(shù)獲取。當(dāng)然你也可以配置uip為DHCP模式，這樣就會(huì)自動(dòng)幫我們配置DNS查詢上級IP。

當(dāng)查找到目的網(wǎng)址的IP或者說查找失敗，都會(huì)調(diào)用void?resolv_found(char *name, u16_t *ipaddr)；這個(gè)函數(shù)需要我們在main里自己實(shí)現(xiàn)：

<span class="hljs-function" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; background: transparent;"><span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span> <span class="hljs-title" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(25, 70, 157); background: transparent;">resolv_found</span><span class="hljs-params" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 0, 255); background: transparent;">(<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">char</span> *name, u16_t *ipaddr)</span> </span>{<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (ipaddr == NULL) {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"Host '%s' not found.\r\n"</span>, name);} <span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">else</span> {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"Found name '%s' = %d.%d.%d.%d\r\n"</span>, name,htons(ipaddr[<span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0</span>]) >> <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">8</span>,htons(ipaddr[<span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0</span>]) & <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0xff</span>,htons(ipaddr[<span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">1</span>]) >> <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">8</span>,htons(ipaddr[<span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">1</span>]) & <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0xff</span>);yeelink_connect(YEELINK_HOST, YEELINK_PORT);} }

如果查找到了yeelink的地址，我們就進(jìn)行tcp連接。

2，client實(shí)現(xiàn)

剩下就是yeelink的client實(shí)現(xiàn)，代碼如下：

<span class="hljs-function" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; background: transparent;"><span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span> <span class="hljs-title" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(25, 70, 157); background: transparent;">yeelink_client_appcall</span><span class="hljs-params" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 0, 255); background: transparent;">(<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span>)</span> </span>{<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_connected()) {yeelink_request_get();<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: connected, waiting for data...\r\n"</span>);<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">return</span>;}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_aborted()) {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: connection aborted\r\n"</span>);}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_timedout()) {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: connection timed out\r\n"</span>);}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_acked()) {yeelink_request_acked();}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> ( uip_rexmit() || uip_newdata()) {yeelink_newdata(); <span class="hljs-comment" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: italic; font-family: inherit; vertical-align: baseline; color: rgb(64, 128, 128); background: transparent;">// 這里的數(shù)據(jù)是分包發(fā)送過來的</span><span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">return</span>;}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_poll()) {<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (yeelink_poll()) {<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">return</span>;}}<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (uip_closed()) {yeelink_closed();<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: connection closed\r\n"</span>);} }

這個(gè)流程按照uip的網(wǎng)絡(luò)編程流程來，這里需要注意幾點(diǎn)：

1，分包

http請求是根據(jù)mss來決定一包里面的有效數(shù)據(jù)長度的。這里就出現(xiàn)了yeelink的http應(yīng)答分包發(fā)送，那么我們在處理http數(shù)據(jù)的時(shí)候就需要考慮到組包。實(shí)現(xiàn)的時(shí)候我取了個(gè)巧。

<span class="hljs-function" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; background: transparent;"><span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">static</span> <span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span> <span class="hljs-title" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(25, 70, 157); background: transparent;">yeelink_newdata</span><span class="hljs-params" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 0, 255); background: transparent;">(<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">void</span>)</span> </span>{yeelink_client.timer = <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0</span>;u16_t len = uip_datalen();<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">memcpy</span>(yeelink_client.data, uip_appdata, len);<span class="hljs-comment" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: italic; font-family: inherit; vertical-align: baseline; color: rgb(64, 128, 128); background: transparent;">//{"timestamp":"2014-03-25T13:40:47","value":0}</span>u8_t *value_info = (u8_t *)<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">strstr</span>(yeelink_client.data, <span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"\"value\""</span>);<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (value_info != NULL) { <span class="hljs-comment" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: italic; font-family: inherit; vertical-align: baseline; color: rgb(64, 128, 128); background: transparent;">// 分片傳送的</span>len = <span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">strlen</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"\"value\":"</span>);u8_t status = *(value_info + len);<span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">if</span> (status == <span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">'0'</span>) {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: switch is close\r\n"</span>);} <span class="hljs-keyword" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(149, 65, 33); background: transparent;">else</span> {<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">printf</span>(<span class="hljs-string" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(33, 145, 97); background: transparent;">"yeelink_client: switch is open\r\n"</span>);}<span class="hljs-built_in" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(0, 134, 179); background: transparent;">memset</span>(yeelink_client.data, <span class="hljs-number" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: inherit; font-family: inherit; vertical-align: baseline; color: rgb(64, 160, 112); background: transparent;">0x00</span> , WEBCLIENT_CONF_MAX_URLLEN);<span class="hljs-comment" style="border: 0px; margin: 0px; padding: 0px; font-weight: inherit; font-style: italic; font-family: inherit; vertical-align: baseline; color: rgb(64, 128, 128); background: transparent;">/*uip_close();*/</span>yeelink_struct_init();} }

2，查詢時(shí)間周期

查詢的時(shí)候似乎并沒有時(shí)間限制，我在poll里面設(shè)置了1s查詢一次，結(jié)果也依然可以返回。之前提到的5s限制并不存在，不知道是否是升級了服務(wù)。

總結(jié)：

uip相對于lwip而言會(huì)更適合物聯(lián)網(wǎng)的開發(fā)，但是編程相對lwip而言會(huì)需要一些技巧性，因?yàn)榕c我們常規(guī)的阻塞式編程有區(qū)別。

代碼的地址如下：https://utopiaprince@bitbucket.org/utopiaprince/uip1.0-stm32-webserver 可以用hg clone。

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