[PATCH] IPV6: added sysctl for maximum number of addresses

[YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@xxxxxxxxxxxxxx>]

Hello.

In some configuration, we need addresses more than 16 addresses per interface.
This pach adds new sysctl for configuring the maximum number of addresses 
per interface.

Thanks in advance.

===== Documentation/networking/ip-sysctl.txt 1.18 vs edited =====
--- 1.18/Documentation/networking/ip-sysctl.txt Thu Dec 25 12:32:23 2003
+++ edited/Documentation/networking/ip-sysctl.txt       Thu Jan 15 21:25:49 2004
@@ -667,6 +667,13 @@
        valid temporary addresses.
        Default: 5
 
+max_addresses - INTEGER
+       Number of maximum addresses per interface.  0 disables limitation.
+       It is recommended not set too large value (or 0) because it would 
+       be too easy way to crash kernel to allow to create too much of 
+       autoconfigured addresses.
+       Default: 16
+
 icmp/*:
 ratelimit - INTEGER
        Limit the maximal rates for sending ICMPv6 packets.
===== include/linux/ipv6.h 1.15 vs edited =====
--- 1.15/include/linux/ipv6.h   Fri Jan  2 05:28:33 2004
+++ edited/include/linux/ipv6.h Thu Jan 15 21:17:23 2004
@@ -143,6 +143,7 @@
        __s32           regen_max_retry;
        __s32           max_desync_factor;
 #endif
+       __s32           max_addresses;
        void            *sysctl;
 };
 
@@ -165,6 +166,7 @@
        DEVCONF_REGEN_MAX_RETRY,
        DEVCONF_MAX_DESYNC_FACTOR,
 #endif
+       DEVCONF_MAX_ADDRESSES,
        DEVCONF_MAX
 };
 
===== include/linux/sysctl.h 1.54 vs edited =====
--- 1.54/include/linux/sysctl.h Thu Dec 25 12:32:23 2003
+++ edited/include/linux/sysctl.h       Thu Jan 15 21:03:14 2004
@@ -418,7 +418,8 @@
        NET_IPV6_TEMP_VALID_LFT=12,
        NET_IPV6_TEMP_PREFERED_LFT=13,
        NET_IPV6_REGEN_MAX_RETRY=14,
-       NET_IPV6_MAX_DESYNC_FACTOR=15
+       NET_IPV6_MAX_DESYNC_FACTOR=15,
+       NET_IPV6_MAX_ADDRESSES=16
 };
 
 /* /proc/sys/net/ipv6/icmp */
===== include/net/addrconf.h 1.11 vs edited =====
--- 1.11/include/net/addrconf.h Sun Jul  6 02:36:23 2003
+++ edited/include/net/addrconf.h       Thu Jan 15 21:05:01 2004
@@ -15,6 +15,8 @@
 
 #define ADDR_CHECK_FREQUENCY           (120*HZ)
 
+#define IPV6_MAX_ADDRESSES             16
+
 struct prefix_info {
        __u8                    type;
        __u8                    length;
===== net/ipv6/addrconf.c 1.79 vs edited =====
--- 1.79/net/ipv6/addrconf.c    Thu Jan  8 05:17:40 2004
+++ edited/net/ipv6/addrconf.c  Thu Jan 15 21:09:43 2004
@@ -81,8 +81,6 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 
-#define IPV6_MAX_ADDRESSES 16
-
 /* Set to 3 to get tracing... */
 #define ACONF_DEBUG 2
 
@@ -160,6 +158,7 @@
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
 #endif
+       .max_addresses          = IPV6_MAX_ADDRESSES,
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt = {
@@ -180,6 +179,7 @@
        .regen_max_retry        = REGEN_MAX_RETRY,
        .max_desync_factor      = MAX_DESYNC_FACTOR,
 #endif
+       .max_addresses          = IPV6_MAX_ADDRESSES,
 };
 
 /* IPv6 Wildcard Address and Loopback Address defined by RFC2553 */
@@ -630,6 +630,7 @@
        unsigned long tmp_prefered_lft, tmp_valid_lft;
        int tmp_plen;
        int ret = 0;
+       int max_addresses;
 
        if (ift) {
                spin_lock_bh(&ift->lock);
@@ -685,9 +686,11 @@
                                 ifp->prefered_lft, 
                                 idev->cnf.temp_prefered_lft - desync_factor / 
HZ);
        tmp_plen = ifp->prefix_len;
+       max_addresses = idev->cnf.max_addresses;
        write_unlock(&idev->lock);
        spin_unlock_bh(&ifp->lock);
-       ift = ipv6_count_addresses(idev) < IPV6_MAX_ADDRESSES ?
+       ift = !max_addresses ||
+             ipv6_count_addresses(idev) < max_addresses ? 
                ipv6_add_addr(idev, &addr, tmp_plen,
                              ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK, 
IFA_F_TEMPORARY) : 0;
        if (!ift || IS_ERR(ift)) {
@@ -1390,10 +1393,13 @@
                ifp = ipv6_get_ifaddr(&addr, dev);
 
                if (ifp == NULL && valid_lft) {
+                       int max_addresses = in6_dev->cnf.max_addresses;
+
                        /* Do not allow to create too much of autoconfigured
                         * addresses; this would be too easy way to crash 
kernel.
                         */
-                       if (ipv6_count_addresses(in6_dev) < IPV6_MAX_ADDRESSES)
+                       if (!max_addresses ||
+                           ipv6_count_addresses(in6_dev) < max_addresses)
                                ifp = ipv6_add_addr(in6_dev, &addr, 
pinfo->prefix_len,
                                                    
addr_type&IPV6_ADDR_SCOPE_MASK, 0);
 
@@ -2722,6 +2728,7 @@
        array[DEVCONF_REGEN_MAX_RETRY] = cnf->regen_max_retry;
        array[DEVCONF_MAX_DESYNC_FACTOR] = cnf->max_desync_factor;
 #endif
+       array[DEVCONF_MAX_ADDRESSES] = cnf->max_addresses;
 }
 
 static int inet6_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
@@ -3050,6 +3057,14 @@
                        .proc_handler   =       &proc_dointvec,
                },
 #endif
+               {
+                       .ctl_name       =       NET_IPV6_MAX_ADDRESSES,
+                       .procname       =       "max_addresses",
+                       .data           =       &ipv6_devconf.max_addresses,
+                       .maxlen         =       sizeof(int),
+                       .mode           =       0644,
+                       .proc_handler   =       &proc_dointvec,
+               },
        },
        .addrconf_dev = {
                {

-- 
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@xxxxxxxxxxxxxx>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA