linux udp收发包例子

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define BUF_SIZE 30

int main(int argc, char *argv[]) {
    int send_sock;
    struct sockaddr_in send_addr;
    char buf[BUF_SIZE];

    if (argc != 3) {
        printf("Usage: %s<IP> <port>\n", argv[0]);
        exit(1);
    }

    send_sock = socket(PF_INET, SOCK_DGRAM, 0);
    if (send_sock == -1) {
        perror("socket() error");
        exit(1);
    }

    memset(&send_addr, 0, sizeof(send_addr));
    send_addr.sin_family = AF_INET;
    send_addr.sin_addr.s_addr = inet_addr(argv[1]);
    send_addr.sin_port = htons(atoi(argv[2]));

    while (1) {
        printf("Enter message: ");
        fgets(buf, BUF_SIZE, stdin);
        buf[strcspn(buf, "\n")] = 0; // Remove newline character

        if (sendto(send_sock, buf, strlen(buf), 0, (struct sockaddr*)&send_addr, sizeof(send_addr)) == -1) {
            perror("sendto() error");
            exit(1);
        }
    }

    close(send_sock);
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>

#define BUF_SIZE 30

int main(int argc, char *argv[]) {
    int recv_sock;
    struct sockaddr_in recv_addr;
    socklen_t addr_size;
    char buf[BUF_SIZE];

    if (argc != 2) {
        printf("Usage: %s <port>\n", argv[0]);
        exit(1);
    }

    recv_sock = socket(PF_INET, SOCK_DGRAM, 0);
    if (recv_sock == -1) {
        perror("socket() error");
        exit(1);
    }

    memset(&recv_addr, 0, sizeof(recv_addr));
    recv_addr.sin_family = AF_INET;
    recv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    recv_addr.sin_port = htons(atoi(argv[1]));

    if (bind(recv_sock, (struct sockaddr*)&recv_addr, sizeof(recv_addr)) == -1) {
        perror("bind() error");
        exit(1);
    }

    addr_size = sizeof(recv_addr);

    while (1) {
        int recv_len = recvfrom(recv_sock, buf, BUF_SIZE, 0, (struct sockaddr*)&recv_addr, &addr_size);
        if (recv_len == -1) {
            perror("recvfrom() error");
            exit(1);
        }
        buf[recv_len] = 0;
        printf("Received message: %s\n", buf);
    }

    close(recv_sock);
    return 0;
}

gcc -o sender sender.c
gcc -o receiver receiver.c

./receiver 8888

./sender 127.0.0.1 8888