解决GlusterFS 1024以下端口问题

GlusterFS是一个开源的分布式文件系统，实际使用中有以下问题：

GlusterFS为了保证客户端连接的时候是root帐户，限制只接受来自客户端1024以下的端口。这样产生两个问题：一是1024以下有许多重要的系统端口可能被GlusterFS占用；二是在连接多个卷、server机器过多（数百台）的时候，会发生端口不够用。

解决办法：将客户端端口限制在800到1024，并复用端口，修改代码如下：

--- glusterfs-2.0.7/transport/socket/src/name.c 2009-10-01 21:19:54.000000000 +0800
+++ glusterfs-2.0.7-1117/transport/socket/src/name.c    2009-10-14 19:27:54.000000000 +0800
@@ -22,6 +22,7 @@
#include <errno.h>
#include <netdb.h>
#include <string.h>
+#include <time.h>

#ifdef CLIENT_PORT_CEILING
#undef CLIENT_PORT_CEILING
@@ -49,19 +50,24 @@ af_inet_bind_to_port_lt_ceiling (int fd,
{
int32_t ret = -1;
/*  struct sockaddr_in sin = {0, }; */
+        static const uint16_t base = 800;
+        ceiling -= base;
uint16_t port = ceiling - 1;
+        uint16_t off = (time(NULL) + rand()) % ceiling;  //使初始端口随机

while (port)
{
+                uint16_t rport = (port+off)%ceiling + base;
+
switch (sockaddr->sa_family)
{
case AF_INET6:
-                        ((struct sockaddr_in6 *)sockaddr)->sin6_port = htons (port);
+                        ((struct sockaddr_in6 *)sockaddr)->sin6_port = htons (rport);
break;

case AF_INET_SDP:
case AF_INET:
-                        ((struct sockaddr_in *)sockaddr)->sin_port = htons (port);
+                        ((struct sockaddr_in *)sockaddr)->sin_port = htons (rport);
break;
}

@@ -403,6 +409,7 @@ client_bind (transport_t *this,
int sock)
{
int ret = 0;
+        int opt = 1;

*sockaddr_len = sizeof (struct sockaddr_in6);
switch (sockaddr->sa_family)
@@ -412,6 +419,8 @@ client_bind (transport_t *this,
*sockaddr_len = sizeof (struct sockaddr_in);

case AF_INET6:
+                ret = setsockopt (sock, SOL_SOCKET, SO_REUSEADDR,
+                         &opt, sizeof (opt));           //复用端口，参考http://blog.csdn.net/liusujian02/archive/2007/12/18/1944520.aspx
ret = af_inet_bind_to_port_lt_ceiling (sock, sockaddr,
*sockaddr_len, CLIENT_PORT_CEILING);
if (ret == -1) {