Linux实现IP地址转换函数的全面指南

#include <arpa/inet.h>

int inet_aton(const char *cp, struct in_addr *inp);

struct in_addr addr;
if (inet_aton("192.168.1.1", &addr)) {
    printf("转换成功: %#x\n", addr.s_addr);
} else {
    perror("转换失败");
}

char *inet_ntoa(struct in_addr in);

struct in_addr addr;
addr.s_addr = htonl(0xC0A80101); // 192.168.1.1
printf("IP地址: %s\n", inet_ntoa(addr));

int inet_pton(int af, const char *src, void *dst);

// IPv4示例
struct in_addr ipv4;
if (inet_pton(AF_INET, "10.0.0.1", &ipv4) <= 0) {
    perror("IPv4转换失败");
}

// IPv6示例
struct in6_addr ipv6;
if (inet_pton(AF_INET6, "2001:db8::1", &ipv6) <= 0) {
    perror("IPv6转换失败");
}

const char *inet_ntop(int af, const void *src, 
                     char *dst, socklen_t size);

// IPv4
char ipv4_str[INET_ADDRSTRLEN];
struct in_addr ipv4_addr;
// ...填充ipv4_addr...
if (!inet_ntop(AF_INET, &ipv4_addr, ipv4_str, INET_ADDRSTRLEN)) {
    perror("转换失败");
} else {
    printf("IPv4: %s\n", ipv4_str);
}

// IPv6
char ipv6_str[INET6_ADDRSTRLEN];
struct in6_addr ipv6_addr;
// ...填充ipv6_addr...
if (!inet_ntop(AF_INET6, &ipv6_addr, ipv6_str, INET6_ADDRSTRLEN)) {
    perror("转换失败");
} else {
    printf("IPv6: %s\n", ipv6_str);
}

int parse_ip_range(const char *start_ip, const char *end_ip, 
                  uint32_t *start, uint32_t *end) {
    struct in_addr addr;
    
    if (!inet_pton(AF_INET, start_ip, &addr)) return -1;
    *start = ntohl(addr.s_addr);
    
    if (!inet_pton(AF_INET, end_ip, &addr)) return -1;
    *end = ntohl(addr.s_addr);
    
    return 0;
}

void log_connection(struct sockaddr_in *client_addr) {
    char ip_str[INET_ADDRSTRLEN];
    time_t now = time(NULL);
    
    inet_ntop(AF_INET, &client_addr->sin_addr, 
             ip_str, sizeof(ip_str));
    
    printf("[%s] 连接来自: %s:%d\n", 
           ctime(&now), 
           ip_str, 
           ntohs(client_addr->sin_port));
}

// 错误示范
char buf[16]; // 对IPv6不够
inet_ntop(AF_INET6, &ipv6addr, buf, sizeof(buf));

// 简易版字符串转IPv4
int my_inet_aton(const char *cp, uint32_t *ip) {
    uint8_t b[4];
    if (sscanf(cp, "%hhu.%hhu.%hhu.%hhu", 
              &b[0], &b[1], &b[2], &b[3]) != 4) {
        return 0;
    }
    *ip = (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
    return 1;
}