将套接字绑定到IPv6地址 [英] Binding Sockets to IPv6 Addresses

问题描述

我正在尝试编写一个同时侦听IPv4和IPv6地址的Web服务器.但是，我最初编写的代码无法正常工作.然后我发现IPv6结构适用于IPv4和IPv6.因此，现在我使用IPv6结构，但是只有IPv4地址有效.这篇帖子为什么我不能将ipv6套接字绑定到一个linklocal地址，它说要添加server.sin6_scope_id = 5;，所以我这样做了，但是它仍然不接受IPv6 telnet连接.任何帮助将不胜感激，因为我被彻底绊倒了.
谢谢！

I am trying to write a web server that listens on both IPv4 and IPv6 addresses. However, the code that I originally wrote did not work. Then I found out that the IPv6 structures work for both IPv4 and IPv6. So now I use the IPv6 structures however, only the IPv4 addresses work. This post, why can't i bind ipv6 socket to a linklocal address, which said to add server.sin6_scope_id = 5; so I did that but it still does not accept IPv6 telnet connections. Any help would be greatly appreciated because I am thoroughly stumped.
Thanks!

我的代码如下:

void initialize_server(int port, int connections, char* address)
{
        struct sockaddr_in6 socket_struct;
        /*Creates the socket*/
        if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        {
                syslog(LOG_ERR, "%s\n", strerror(errno));
                exit(EXIT_FAILURE);
        }/*Ends the socket creation*/

        /*Populates the socket address structure*/
                socket_struct.sin6_family = AF_INET6;

        if(address == NULL)
                socket_struct.sin6_addr=in6addr_any;
        else
        {
                inet_pton(AF_INET6, "fe80::216:3eff:fec3:3c22", (void *)&socket_struct.sin6_addr.s6_addr);
        }
        socket_struct.sin6_port =htons(port);
        socket_struct.sin6_scope_id = 0;
        if (bind(sock_fd, (struct sockaddr*) &socket_struct, sizeof(socket_struct)) < 0)
        {
                syslog(LOG_ERR, "%s\n", strerror(errno));
                exit(EXIT_FAILURE);
        }//Ends the binding.

        if (listen(sock_fd, connections) <0)
        {
                syslog(LOG_ERR, "%s\n", strerror(errno));
                exit(EXIT_FAILURE);
        }//Ends the listening function

}//ends the initialize server function.

推荐答案

说"server.sin6_scope_id = 5;"是任意的.我自己为此打了一段时间，发现您需要使用要绑定的实际接口的实际作用域.可以发现它，但有用却很少.

Saying "server.sin6_scope_id = 5;" is arbitrary. I fought with this awhile myself and discovered you need to use the actual scope of the actual interface you want to bind on. It can be found with an obsure but useful little function.

#include <net/if.h>
server.sin6_scope_id=if_nametoindex("eth0");

当然，将其硬编码到一个特定的适配器是不好的，短视的编码.一个更完整的解决方案是遍历所有这些对象，并在您要绑定的IP地址上进行匹配.以下内容并不是完美的，因为它没有考虑到具有非规范地址和两个具有相同ip的适配器等怪癖.但是，总的来说，此示例功能很好用，应该让您入门.

Of course, hardcoding it to one particular adapter is bad, shortsighted coding. A more complete solution is to loop through all of them and match on the ip address you're binding. The following is not perfect in that it doesn't account for quirks like having non-canonical addresses and two adapters with the same ip, etc. But besoverall, this sample function works great and should get you started.

#include <string.h> // strcmp
#include <net/if.h> // if_nametoindex()
#include <ifaddrs.h> // getifaddrs()
#include <netdb.h> // NI_ constants

// returns 0 on error
unsigned getScopeForIp(const char *ip){
    struct ifaddrs *addrs;
    char ipAddress[NI_MAXHOST];
    unsigned scope=0;
    // walk over the list of all interface addresses
    getifaddrs(&addrs);
    for(ifaddrs *addr=addrs;addr;addr=addr->ifa_next){
        if (addr->ifa_addr && addr->ifa_addr->sa_family==AF_INET6){ // only interested in ipv6 ones
            getnameinfo(addr->ifa_addr,sizeof(struct sockaddr_in6),ipAddress,sizeof(ipAddress),NULL,0,NI_NUMERICHOST);
            // result actually contains the interface name, so strip it
            for(int i=0;ipAddress[i];i++){
                if(ipAddress[i]=='%'){
                    ipAddress[i]='\0';
                    break;
                }
            }
            // if the ip matches, convert the interface name to a scope index
            if(strcmp(ipAddress,ip)==0){
                scope=if_nametoindex(addr->ifa_name);
                break;
            }
        }
    }
    freeifaddrs(addrs);
    return scope;
}

这篇关于将套接字绑定到IPv6地址的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！