在linux上,当使用C执行与端口0(选择随机端口)的套接字绑定时,我

因此,我们有一个长期存在的商业产品,这已经很成熟,我以前从未见过这类问题.我们使用客户端程序将数据发送到服务器.有时,由于客户环境中的防火墙,我们允许最终用户指定要绑定的出站端口范围,但是,在我看到的这个特定问题中,我们没有这样做,并且正在使用端口0来执行绑定.从我读过的所有内容来看,这意味着选择一个随机端口.但我无法找到的是,这对内核/操作系统意味着什么.如果我要求一个随机端口,那么它是如何使用的呢？
严格来说,只有src ip / src端口的唯一配对. dst ip / port使连接唯一.我相信可以使用相同的端口,如果与另一个目标IP通信,但也许这与此无关.

此外,这不会发生在所有客户的系统上,只有一些.因此,这可能是某种形式的负载相关问题.据我所知,系统相当繁忙.

这是我们正在使用的代码.我遗漏了一些用于windows的ifdef代码,并在绑定后省略了我们的操作.

_SocketCreateClient(Socket_pwtP sock,SocketInfoP sInfo )
{
int nRetries;                       /* number of times to try connect()  */
unsigned short port;
BOOL success = FALSE;
BOOL gotaddr = FALSE;
char buf[INET6_ADDRSTRLEN] ="";
int connectsuccess =1;
int ipv6compat =0;

#ifdef SOCKET_SEND_TIMEOUT
struct timeval time;
#endif /* SOCKET_SEND_TIMEOUT */

nRetries = sInfo->si_nRetries;
sock->s_hostName = strdup(sInfo->si_hostName);

#ifdef DEBUG_SOCKET
LogWrite(LogF,LOG_WARNING,"Socket create client");
LogWrite(LogF,"Number of retries = %d",nRetries);
#endif

ipv6compat = GetIPVer();
if (ipv6compat == -1) /* ipv6 not supported */
    gotaddr = GetINAddr(sInfo->si_hostName,&sock->s_sAddr.sin_addr);
else
    gotaddr = GetINAddr6(sInfo->si_hostName,&sock->s_sAddr6.sin6_addr);

/* translate supplied host name to an internet address */
if (!gotaddr) {
                        /* print this message only once */
                        if ( sInfo->si_logInfo && ( sInfo->si_nRetries == 1 ) )
                        {
                           LogWrite(LogF,LOG_ERR,"unable to resolve ip address for host '%s'",sInfo->si_hostName);
                        }
                        sock = _SocketDestroy(sock);
}

else {

    if (ipv6compat == 1) /* ipv6 supported */
    {
            /* try to print the address in sock->s_sAddr6.sin6_addr to make sure it's good.  from call above */
            LogWrite(LogF,LOG_DEBUG2,"Before call to inet_ntop");
            inet_ntop(AF_INET6,&sock->s_sAddr6.sin6_addr,buf,sizeof(buf));
            LogWrite (LogF,"Value of sock->s_sAddr6.sin6_addr from GetINAddr6: %s",buf);


            LogWrite (LogF,"Value of sock->s_sAddr6.sin6_scope_id from if_nametoindex: %d",sock->s_sAddr6.sin6_scope_id);

            LogWrite (LogF,"Value of sock->s_type: %d",sock->s_type);
    }


    /* try to create the socket nRetries times */
    while (sock && sock->s_id == INVALID_SOCKET) {
        int socketsuccess = FALSE;

        /* create the actual socket */

        if (ipv6compat == -1) /* ipv6 not supported */
            socketsuccess = sock->s_id = socket(AF_INET,sock->s_type,0);
        else
            socketsuccess = sock->s_id = socket(AF_INET6,0);

        if ((socketsuccess) == INVALID_SOCKET) {
            GETLASTERROR;
            LogWrite(LogF,"unable to create socket: Error %d: %s",errno,strerror(errno) );
            sock = _SocketDestroy(sock);
        }
        else
        {

             /* cycle through outbound port range for firewall support */
            port = sInfo->si_startPortRange;
         while ( !success && port <= sInfo->si_endPortRange ) {
                    int bindsuccess = 1;

             /* bind to outbound port number */
                    if ( ipv6compat == -1) /* ipv6 not supported */
                    {
                            sock->s_sourceAddr.sin_port   = htons(port);
                            bindsuccess = bind(sock->s_id,(struct sockaddr *) &sock->s_sourceAddr,sizeof(sock->s_sourceAddr));

                    }

                    else {
                            sock->s_sourceAddr6.sin6_port   = htons(port);
                            inet_ntop(AF_INET6,&sock->s_sourceAddr6.sin6_addr,sizeof(buf));
                            LogWrite(LogF,LOG_DEBUG,"attempting bind to s_sourceAddr6 %s ",buf);

                            bindsuccess = bind(sock->s_id,(struct sockaddr *) &sock->s_sourceAddr6,sizeof(sock->s_sourceAddr6));
                    }

                     if (bindsuccess == -1) {
                            GETLASTERROR;
                            LogWrite(LogF,"unable to bind port %d to socket: Error %d: %s. Will attempt next port if protomgr port rules configured(EAV_PORTS).",port,strerror(errno) );

                            /* if port in use,try next port number */
                          port++;
              }
              else {
                    /* only log if outbound port was specified */
                    if (port != 0)
                             {
                               if ( sInfo->si_sourcehostName ) {
                                  LogWrite(LogF,"bound outbound address %s:%d to socket",sInfo->si_sourcehostName,port);
                               }
                               else {
                                  LogWrite(LogF,"bound outbound port %d to socket",port);
                               }
                            }
                            success = TRUE;
              }


         }
        }
    }
}
return(sock);
}

我们在日志文件中看到的错误如下所示.它正在进行2次尝试并且都失败了：

protomgr [628453]：错误：无法将端口0绑定到套接字：错误98：地址已在使用中.如果配置了protomgr端口规则(EAV_PORTS),将尝试下一个端口.

protomgr [628453]：错误：无法将端口绑定到套接字：错误98：地址已在使用中.如果此消息来自protomgr,请考虑增加EAV_PORTS的数量.

protomgr [628453]：错误：无法将端口0绑定到套接字：错误98：地址已在使用中.如果配置了protomgr端口规则(EAV_PORTS),请考虑增加EAV_PORTS的数量.