linux 对udp监听

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

#define BUF_SIZE 1024

int main(int argc, char *argv[]) {
    int serv_sock, clnt_sock;
    char buf[BUF_SIZE];
    int str_len;
    struct sockaddr_in serv_addr, clnt_addr;
    socklen_t clnt_addr_size;

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

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

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

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

    while (1) {
        clnt_addr_size = sizeof(clnt_addr);
        str_len = recvfrom(serv_sock, buf, BUF_SIZE - 1, 0,
                            (struct sockaddr*)&clnt_addr, &clnt_addr_size);
        if (str_len == -1) {
            perror("recvfrom() error");
            continue;
        }
        buf[str_len] = '\0';
        printf("Received message: %s
", buf);
    }

    close(serv_sock);
    return 0;
}