UDP socket实例

Server#include <lwip/sockets.h> #define RECEIVER_PORT_NUM 6001 #define RECEIVER_IP_ADDR "192.136.23.21" void main(void){int socket_fd;struct sockaddr_in sa,ra;int recv_data; char data_buffer[80]; /* Creates an UDP socket (SOCK_DGRAM) with Internet Protocol Family (PF_INET). * Protocol family and Address family related. For example PF_INET Protocol Family and AF_INET family are coupled.*/socket_fd = socket(PF_INET, SOCK_DGRAM, 0);if ( socket_fd < 0 ){printf("socket call failed");exit(0);}memset(&sa, 0, sizeof(struct sockaddr_in));ra.sin_family = AF_INET;ra.sin_addr.s_addr = inet_addr(RECEIVER_IP_ADDR);ra.sin_port = htons(RECEIVER_PORT_NUM);/* Bind the UDP socket to the port RECEIVER_PORT_NUM and to the current* machines IP address (Its defined by RECEIVER_PORT_NUM).* Once bind is successful for UDP sockets application can operate* on the socket descriptor for sending or receiving data.*/if (bind(socket_fd, (struct sockaddr *)&ra, sizeof(struct sockaddr_in)) == -1){printf("Bind to Port Number %d ,IP address %s failed\n",RECEIVER_PORT_NUM,RECEIVER_IP_ADDR);close(socket_fd);exit(1);}/* RECEIVER_PORT_NUM is port on which Server waits for data to* come in. It copies the received data into receive buffer and* prints the received data as string. If no data is available it * blocks.recv calls typically return any availbale data on the socket instead of waiting for the entire data to come.*/recv_data = recv(socket_fd,data_buffer,sizeof(data_buffer),0);if(recv_data > 0){data_buffer[recv_data] = '\0';printf("%s\n",data_buffer);} close(socket_fd);}UDP Client Server ExampleClient#include <lwip/sockets.h> #define SENDER_PORT_NUM 6000 #define SENDER_IP_ADDR "192.136.23.20"#define RECEIVER_PORT_NUM 6001 #define RECEIVER_IP_ADDR "192.136.23.21" void main(void){int socket_fd;struct sockaddr_in sa;int sent_data; char recv_data_buffer[80]; /* Creates an UDP socket (SOCK_DGRAM) with Internet Protocol Family (PF_INET). * Protocol family and Address family related. For example PF_INET Protocol Family and AF_INET family are coupled.*/socket_fd = socket(PF_INET, SOCK_DGRAM, 0);if ( socket_fd < 0 ){printf("socket call failed");exit(0);}memset(&sa, 0, sizeof(struct sockaddr_in));sa.sin_family = AF_INET;sa.sin_addr.s_addr = inet_addr(SENDER_IP_ADDR);sa.sin_port = htons(SENDER_PORT_NUM);/* Bind the TCP socket to the port SENDER_PORT_NUM and to the current* machines IP address (Its defined by SENDER_IP_ADDR). * Once bind is successful for UDP sockets application can operate* on the socket descriptor for sending or receiving data.*/if (bind(socket_fd, (struct sockaddr *)&sa, sizeof(struct sockaddr_in)) == -1){printf("Bind to Port Number %d ,IP address %s failed\n",SENDER_PORT_NUM,SENDER_IP_ADDR);close(socket_fd);exit(1);}memset(&ra, 0, sizeof(struct sockaddr_in));ra.sin_family = AF_INET;ra.sin_addr.s_addr = inet_addr(RECEIVER_IP_ADDR);ra.sin_port = htons(RECEIVER_PORT_NUM);strcpy(data_buffer,"Hello World");sent_data = sendto(socket_fd, data_buffer,sizeof("Hello World",0,(struct sockaddr*)&ra,sizeof(ra)));if(sent_data < 0){printf("send failed\n");close(socket_fd);exit(2);} close(socket_fd);}