写一个端口扫描的c语言程序

好的，以下是一个简单的端口扫描的C语言程序，它可以扫描目标主机的特定端口是否开放：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAX_PORTS 1000

int main(int argc, char *argv[]) {
    int sockfd, ret, start, end, i, j;
    struct sockaddr_in target_addr;
    char *target_ip, port_status[MAX_PORTS];
    
    if (argc != 4) {
        printf("Usage: %s <target IP> <start port> <end port>\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    
    target_ip = argv[1];
    start = atoi(argv[2]);
    end = atoi(argv[3]);
    
    if (start < 1 || end < 1 || start > MAX_PORTS || end > MAX_PORTS) {
        printf("Invalid port range\n");
        exit(EXIT_FAILURE);
    }
    
    if (start > end) {
        printf("Invalid port range: start port must be less than or equal to end port\n");
        exit(EXIT_FAILURE);
    }
    
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1) {
        printf("Failed to create socket: %s\n", strerror(errno));
        exit(EXIT_FAILURE);
    }
    
    memset(&target_addr, 0, sizeof(target_addr));
    target_addr.sin_family = AF_INET;
    target_addr.sin_addr.s_addr = inet_addr(target_ip);
    
    // Scan ports
    for (i = start; i <= end; i++) {
        target_addr.sin_port = htons(i);
        ret = connect(sockfd, (struct sockaddr *)&target_addr, sizeof(target_addr));
        if (ret == 0) {
            printf("Port %d is open\n", i);
            port_status[i] = 1;
        } else {
            port_status[i] = 0;
        }
    }
    
    printf("Port scan completed. Open ports: ");
    for (j = start; j <= end; j++) {
        if (port_status[j] == 1) {
            printf("%d ", j);
        }
    }
    
    printf("\n");
    close(sockfd);
    return 0;
}

请注意，这个程序需要在Linux或Unix系统上运行，因为它使用了Unix网络编程API。如果需要在Windows上运行，请使用Winsock API。