使用ioctl分配ipv6地址

Question

我正嘗試使用ioctl爲接口分配IPv6地址，但徒勞無益。以下是我使用的代碼：

#include <errno.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <stddef.h>    
#include <net/if.h> 
#include <unistd.h> 
#include <sys/ioctl.h> 
#include <linux/sockios.h> 
#include <netinet/in.h> 
#include <sys/socket.h> 
#include <arpa/inet.h> 

#define IFNAME "eth1" 
#define HOST "fec2::22" 
#define ifreq_offsetof(x) offsetof(struct ifreq, x) 

int main(int argc, char **argv) { 
    struct ifreq ifr; 
    struct sockaddr_in6 sai; 
    int sockfd;      /* socket fd we use to manipulate stuff with */ 
    int selector; 
    unsigned char mask; 

    char *p; 

    /* Create a channel to the NET kernel. */ 
    sockfd = socket(AF_INET6, SOCK_DGRAM, 0); 
    if (sockfd == -1) { 
    printf("Bad fd\n"); 
    return -1; 
    } 

    /* get interface name */ 
    strncpy(ifr.ifr_name, IFNAME, IFNAMSIZ); 

    memset(&sai, 0, sizeof(struct sockaddr)); 
    sai.sin6_family = AF_INET6; 
    sai.sin6_port = 0; 

    //if(inet_aton(HOST, &sai.sin_addr.s_addr) == 0) { 
    if(inet_pton(AF_INET6, HOST, (void *)&sai.sin6_addr) <= 0) { 
    //&((struct sockaddr_in*)&sa)->sin_addr 
    printf("Bad address\n"); 
    return -1; 
    } 

    p = (char *) &sai; 
    memcpy((((char *)&ifr + ifreq_offsetof(ifr_addr))), 
      p, sizeof(struct sockaddr)); 

    int ret = ioctl(sockfd, SIOCSIFADDR, &ifr); 
    printf("ret: %d\terrno: %d\n", ret, errno); 
    ioctl(sockfd, SIOCGIFFLAGS, &ifr); 
    printf("ret: %d\terrno: %d\n", ret, errno); 

    ifr.ifr_flags |= IFF_UP | IFF_RUNNING; 
    // ifr.ifr_flags &= ~selector; // unset something 

    ioctl(sockfd, SIOCSIFFLAGS, &ifr); 
    printf("ret: %d\terrno: %d\n", ret, errno); 
    close(sockfd); 
    return 0; 
} 

ioctl調用失敗，說ENODEV。當套接字系列更改爲sockfd = socket(AF_INET, SOCK_DGRAM, 0);時，這些調用再次失敗，說EINVAL。

通過使用 sockaddr_in代替，我能夠使用上述代碼爲接口分配IPv4地址。

是不是可以使用ioctl分配IPv6地址？

Answer 1

從'ifconfig'命令的linux實現中汲取靈感，我可以在接口上設置IPv6地址。下面是它的代碼：

#include <errno.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <stddef.h>    
#include <net/if.h> 
#include <unistd.h> 
#include <sys/ioctl.h> 
#include <linux/sockios.h> 
#include <netinet/in.h> 
#include <sys/socket.h> 
#include <arpa/inet.h> 
#if __GLIBC__ >=2 && __GLIBC_MINOR >= 1 
#include <netpacket/packet.h> 
#include <net/ethernet.h> 
#else 
#include <asm/types.h> 
#include <linux/if_ether.h> 
#endif 

#define IFNAME "eth0" 
#define HOST "fec2::22" 
#define ifreq_offsetof(x) offsetof(struct ifreq, x) 

struct in6_ifreq { 
    struct in6_addr ifr6_addr; 
    __u32 ifr6_prefixlen; 
    unsigned int ifr6_ifindex; 
}; 

int main(int argc, char **argv) { 

    struct ifreq ifr; 
    struct sockaddr_in6 sai; 
    int sockfd;      
    struct in6_ifreq ifr6; 

    sockfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP); 
    if (sockfd == -1) { 
      printf("Bad fd\n"); 
      return -1; 
    } 

    /* get interface name */ 
    strncpy(ifr.ifr_name, IFNAME, IFNAMSIZ); 

    memset(&sai, 0, sizeof(struct sockaddr)); 
    sai.sin6_family = AF_INET6; 
    sai.sin6_port = 0; 

    if(inet_pton(AF_INET6, HOST, (void *)&sai.sin6_addr) <= 0) { 
     printf("Bad address\n"); 
     return -1; 
    } 

    memcpy((char *) &ifr6.ifr6_addr, (char *) &sai.sin6_addr, 
       sizeof(struct in6_addr)); 

    if (ioctl(sockfd, SIOGIFINDEX, &ifr) < 0) { 
     perror("SIOGIFINDEX"); 
    } 
    ifr6.ifr6_ifindex = ifr.ifr_ifindex; 
    ifr6.ifr6_prefixlen = 64; 
    if (ioctl(sockfd, SIOCSIFADDR, &ifr6) < 0) { 
     perror("SIOCSIFADDR"); 
    } 

    ifr.ifr_flags |= IFF_UP | IFF_RUNNING; 

    int ret = ioctl(sockfd, SIOCSIFFLAGS, &ifr); 
    printf("ret: %d\terrno: %d\n", ret, errno); 

    close(sockfd); 
    return 0; 
} 

Answer 2

基於@ maddy的回答，我做了一個更簡潔的版本，這個版本更容易適應。訣竅是struct in6_ifreq結構必須傳遞給ioctl。

#include <stdint.h> 
#include <string.h> 
#include <sys/ioctl.h> 
#include <net/if.h> 
#include <netinet/in.h> 

#define IFNAME "eth0" 
#define HOST "2001::22" 

struct in6_ifreq { 
    struct in6_addr addr; 
    uint32_t  prefixlen; 
    unsigned int ifindex; 
}; 

int main(int argc, char **argv) { 

    struct ifreq ifr; 
    struct in6_ifreq ifr6; 
    int sockfd; 
    int err; 

    // Create IPv6 socket to perform the ioctl operations on 
    sockfd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_IP); 

    // Copy the interface name to the ifreq struct 
    strncpy(ifr.ifr_name, IFNAME, IFNAMSIZ); 
    // Get the ifrindex of the interface 
    err = ioctl(sockfd, SIOGIFINDEX, &ifr); 

    // Prepare the in6_ifreq struct and set the address to the interface 
    inet_pton(AF_INET6, HOST, &ifr6.addr); 
    ifr6.ifindex = ifr.ifr_ifindex; 
    ifr6.prefixlen = 64; 
    err = ioctl(sockfd, SIOCSIFADDR, &ifr6); 

    close(sockfd); 
    return 0; 
} 

我忘了所有的錯誤檢查的可讀性，但應檢查命令的錯誤。