多个UDP监听同一个端口
测试结果：客户端的数据总是发给最后一个打开的服务器
服务器代码：socket()->setsockopt()->bind()->recvfrom()/sendto()
1 #include <stdio.h> 2 #include <sys/socket.h> 3 #include <sys/types.h> 4 #include <arpa/inet.h> 5 #include <netinet/in.h> 6 #include <unistd.h> 7 #include <string.h> 8 #include <stdlib.h> 9 10 11 int main(int argc, char const *argv[]) { 12 int serverfd; 13 sockaddr_in sadd, cadd; 14 int port = atoi(argv[1]); 15 16 serverfd = socket(AF_INET, SOCK_DGRAM, 0); 17 int on = 1; 18 setsockopt(serverfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); 19 20 bzero(&sadd, sizeof(sadd)); 21 sadd.sin_family = AF_INET; 22 sadd.sin_addr.s_addr = htonl(INADDR_ANY); 23 sadd.sin_port = htons(port); 24 25 bind(serverfd, (sockaddr*)&sadd, sizeof(sadd)); 26 27 int i = 0; 28 while(1) { 29 char msg[1024]; 30 socklen_t len = sizeof(cadd); 31 int n; 32 n = recvfrom(serverfd, msg, 1024, 0,(sockaddr*)&cadd, &len); 33 printf("%d\n", i++); 34 sendto(serverfd, msg, n, 0, (sockaddr*)&cadd, len); 35 } 36 37 }
客户端代码：socket()->sendto()/recvfrom()
1 #include <stdio.h> 2 #include <sys/socket.h> 3 #include <sys/types.h> 4 #include <arpa/inet.h> 5 #include <netinet/in.h> 6 #include <unistd.h> 7 #include <string.h> 8 #include <stdlib.h> 9 10 int main(int argc, char const *argv[]) 11 { 12 int fd; 13 sockaddr_in saddr; 14 int port = atoi(argv[1]); 15 16 fd = socket(AF_INET, SOCK_DGRAM, 0); 17 18 bzero(&saddr, sizeof(saddr)); 19 saddr.sin_family = AF_INET; 20 saddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 21 saddr.sin_port = htons(port); 22 23 while(1) { 24 sleep(atoi(argv[2])); 25 char msg[1024] = "aaaaa"; 26 //scanf("%s", msg); 27 socklen_t len = sizeof(saddr); 28 sendto(fd, msg, strlen(msg), 0, (sockaddr*)&saddr, len); 29 int n = recvfrom(fd, msg, 1024, 0, nullptr, nullptr); 30 printf("%s\n", msg); 31 } 32 }
