日志
４、UDP编程
| ****************** * 第四讲 UDP编程 * ****************** 很多网友需要跑TCP/IP协议栈，那么用ecos是再惬意不过的事情了。ecos自身提供三种完整协议栈：FreeBSD、OpenBSD、lwip，当然如果你愿意，也可以移植其他协议栈，爽吧！ 我配置的ecos系统选择了FreeBSD栈，功能非常强大，该有的基本都有，标准接口，与PC机上网络开发没有任何区别。ecos自带测试范例，改改就能直接应用。 UDP的优点是开销小，速度快；缺点是面向无连接，无纠错能力。UDP在网络实时应用中用得很多。 下面是UDP测试源码，略微不同的是一开始要先执行“init_all_network_interfaces();”，同时判断网卡是否安装(条件判断CYGHWR_NET_DRIVER_ETH0)。剩下的部分就全是标准写法。这里用到的一些socket函数有阻塞功能，不需要额外延时，所以处理速度很快。 UDP测试源码 //此程序配合上位机UDP测试程序 #include <network.h> #include <pkgconf/system.h> #include <pkgconf/net.h> #include <cyg/infra/testcase.h> #ifdef CYGBLD_DEVS_ETH_DEVICE_H // Get the device config if it exists #include CYGBLD_DEVS_ETH_DEVICE_H // May provide CYGTST_DEVS_ETH_TEST_NET_REALTIME #endif #ifdef CYGPKG_NET_TESTS_USE_RT_TEST_HARNESS // do we use the rt test? # ifdef CYGTST_DEVS_ETH_TEST_NET_REALTIME // Get the test ancilla if it exists # include CYGTST_DEVS_ETH_TEST_NET_REALTIME # endif #endif #define STACK_SIZE (CYGNUM_HAL_STACK_SIZE_TYPICAL + 0x1000) static char stack[STACK_SIZE],stack1[STACK_SIZE]; static cyg_thread thread_data,thread_data1; static cyg_handle_t thread_handle,thread_handle1; void pexit(char *s) { CYG_TEST_FAIL_FINISH(s); } void udp_test(struct bootp *bp) { struct sockaddr_in host,client; int s,len,c_len; unsigned char buf[100]; unsigned char msga[] = {"YY:www.armecos.com"}; unsigned char msge[] = {"Error!"}; unsigned char num = 5; s = socket(AF_INET, SOCK_DGRAM, 0); if (s < 0) { pexit("socket"); return; } // Set up host address host.sin_family = AF_INET; host.sin_len = sizeof(host); host.sin_addr.s_addr = INADDR_ANY; host.sin_port = ntohs(1025); if(bind(s, (struct sockaddr *) &host, sizeof(host)) < 0) { pexit("bind /source/ error"); } while(true){ c_len = sizeof(client); len = recvfrom(s, buf, sizeof(buf),0,(struct sockaddr *)&client,&c_len); if(len > 0){ if(buf[0] == 'A') num = 5; else len = sendto(s,buf,sizeof(buf),0,(struct sockaddr *)&client,sizeof(client)); } while(num != 0){ len = sendto(s,msga,sizeof(msga),0,(struct sockaddr *)&client,sizeof(client)); if(len != sizeof(msga)) len = sendto(s,msge,sizeof(msge),0,(struct sockaddr *)&client,sizeof(client)); //cyg_thread_delay(10); num--; } } } void net_test(cyg_addrword_t p) { diag_printf("Start Networking Test...\n"); init_all_network_interfaces(); #ifdef CYGHWR_NET_DRIVER_ETH0 if (eth0_up) { cyg_thread_create(10, // Priority - just a number udp_test, // entry (cyg_addrword_t)ð0_bootp_data, // entry parameter "Network udp test", // Name &stack1[0], // Stack STACK_SIZE, // Size &thread_handle1, // Handle &thread_data1 // Thread data structure ); cyg_thread_resume(thread_handle1); // Start it } #endif } void cyg_start(void) { // Create a main thread, so we can run the scheduler and have time 'pass' cyg_thread_create(10, // Priority - just a number net_test, // entry 0, // entry parameter "Network test", // Name &stack[0], // Stack STACK_SIZE, // Size &thread_handle, // Handle &thread_data // Thread data structure ); cyg_thread_resume(thread_handle); // Start it cyg_scheduler_start(); } |
