Re: [PATCH] IPv6: Don't assign a same IPv6 address on a same

YOSHIFUJI Hideaki / =?ISO-2022-jp?B?GyRCNUhGIzFRTEAbKEI=?= (yoshfuji@linux-ipv6.org)
Mon, 31 Mar 2003 10:34:51 +0900 (JST)


In article <20030331.033524.114862210.yoshfuji@linux-ipv6.org> (at Mon, 31 Mar 2003 03:35:24 +0900 (JST)), YOSHIFUJI Hideaki / $B5HF#1QL@(B <yoshfuji@linux-ipv6.org> says:

> In article <20030330163656.GA18645@ferrara.linux.it> (at Sun, 30 Mar 2003 18:36:56 +0200), Simone Piunno <pioppo@ferrara.linux.it> says:
>
> > - locking inside ipv6_add_addr() is simpler and more linear but
> > semantically wrong because you're unable to tell the user why his
> > "ip addr add" failed. E.g. you answer ENOBUFS instead of EEXIST.
>
> We don't want to create duplicate address in any case.
> ipv6_add_addr() IS right place.
> And, we can return error code by using IS_ERR() etc.
> I'll fix this.

Here's the revised patch.
Thank you.

Index: net/ipv6/addrconf.c
===================================================================
RCS file: /cvsroot/usagi/usagi-backport/linux25/net/ipv6/addrconf.c,v
retrieving revision 1.1.1.9
retrieving revision 1.1.1.9.2.6
diff -u -r1.1.1.9 -r1.1.1.9.2.6
--- net/ipv6/addrconf.c 25 Mar 2003 04:33:45 -0000 1.1.1.9
+++ net/ipv6/addrconf.c 30 Mar 2003 18:51:29 -0000 1.1.1.9.2.6
@@ -30,6 +30,8 @@
* address validation timer.
* YOSHIFUJI Hideaki @USAGI : Privacy Extensions (RFC3041)
* support.
+ * Yuji SEKIYA @USAGI : Don't assign a same IPv6
+ * address on a same interface.
*/

#include <linux/config.h>
@@ -126,6 +128,8 @@
static void addrconf_rs_timer(unsigned long data);
static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifa);

+static int ipv6_chk_same_addr(const struct in6_addr *addr, struct net_device *dev);
+
static struct notifier_block *inet6addr_chain;

struct ipv6_devconf ipv6_devconf =
@@ -492,12 +496,23 @@
{
struct inet6_ifaddr *ifa;
int hash;
+ static spinlock_t lock = SPIN_LOCK_UNLOCKED;
+
+ spin_lock_bh(&lock);
+
+ /* Ignore adding duplicate addresses on an interface */
+ if (ipv6_chk_same_addr(addr, idev->dev)) {
+ spin_unlock_bh(&lock);
+ ADBG(("ipv6_add_addr: already assigned\n"));
+ return ERR_PTR(-EEXIST);
+ }

ifa = kmalloc(sizeof(struct inet6_ifaddr), GFP_ATOMIC);

if (ifa == NULL) {
+ spin_unlock_bh(&lock);
ADBG(("ipv6_add_addr: malloc failed\n"));
- return NULL;
+ return ERR_PTR(-ENOBUFS);
}

memset(ifa, 0, sizeof(struct inet6_ifaddr));
@@ -513,8 +528,9 @@
read_lock(&addrconf_lock);
if (idev->dead) {
read_unlock(&addrconf_lock);
+ spin_unlock_bh(&lock);
kfree(ifa);
- return NULL;
+ return ERR_PTR(-ENODEV); /*XXX*/
}

inet6_ifa_count++;
@@ -551,6 +567,7 @@
in6_ifa_hold(ifa);
write_unlock_bh(&idev->lock);
read_unlock(&addrconf_lock);
+ spin_unlock_bh(&lock);

notifier_call_chain(&inet6addr_chain,NETDEV_UP,ifa);

@@ -697,7 +714,7 @@
ift = ipv6_count_addresses(idev) < IPV6_MAX_ADDRESSES ?
ipv6_add_addr(idev, &addr, tmp_plen,
ipv6_addr_type(&addr)&IPV6_ADDR_SCOPE_MASK, IFA_F_TEMPORARY) : 0;
- if (!ift) {
+ if (IS_ERR(ift)) {
in6_dev_put(idev);
in6_ifa_put(ifp);
printk(KERN_INFO
@@ -928,6 +945,23 @@
return ifp != NULL;
}

+static
+int ipv6_chk_same_addr(const struct in6_addr *addr, struct net_device *dev)
+{
+ struct inet6_ifaddr * ifp;
+ u8 hash = ipv6_addr_hash(addr);
+
+ read_lock_bh(&addrconf_hash_lock);
+ for(ifp = inet6_addr_lst[hash]; ifp; ifp=ifp->lst_next) {
+ if (ipv6_addr_cmp(&ifp->addr, addr) == 0) {
+ if (dev == NULL || ifp->idev->dev == dev)
+ break;
+ }
+ }
+ read_unlock_bh(&addrconf_hash_lock);
+ return ifp != NULL;
+}
+
struct inet6_ifaddr * ipv6_get_ifaddr(struct in6_addr *addr, struct net_device *dev)
{
struct inet6_ifaddr * ifp;
@@ -1344,7 +1378,7 @@
ifp = ipv6_add_addr(in6_dev, &addr, pinfo->prefix_len,
addr_type&IPV6_ADDR_SCOPE_MASK, 0);

- if (ifp == NULL) {
+ if (IS_ERR(ifp)) {
in6_dev_put(in6_dev);
return;
}
@@ -1499,13 +1533,14 @@

scope = ipv6_addr_scope(pfx);

- if ((ifp = ipv6_add_addr(idev, pfx, plen, scope, IFA_F_PERMANENT)) != NULL) {
+ ifp = ipv6_add_addr(idev, pfx, plen, scope, IFA_F_PERMANENT);
+ if (!IS_ERR(ifp)) {
addrconf_dad_start(ifp);
in6_ifa_put(ifp);
return 0;
}

- return -ENOBUFS;
+ return PTR_ERR(ifp);
}

static int inet6_addr_del(int ifindex, struct in6_addr *pfx, int plen)
@@ -1597,7 +1632,7 @@

if (addr.s6_addr32[3]) {
ifp = ipv6_add_addr(idev, &addr, 128, scope, IFA_F_PERMANENT);
- if (ifp) {
+ if (!IS_ERR(ifp)) {
spin_lock_bh(&ifp->lock);
ifp->flags &= ~IFA_F_TENTATIVE;
spin_unlock_bh(&ifp->lock);
@@ -1633,7 +1668,7 @@

ifp = ipv6_add_addr(idev, &addr, plen, flag,
IFA_F_PERMANENT);
- if (ifp) {
+ if (!IS_ERR(ifp)) {
spin_lock_bh(&ifp->lock);
ifp->flags &= ~IFA_F_TENTATIVE;
spin_unlock_bh(&ifp->lock);
@@ -1660,7 +1695,7 @@
}

ifp = ipv6_add_addr(idev, &in6addr_loopback, 128, IFA_HOST, IFA_F_PERMANENT);
- if (ifp) {
+ if (!IS_ERR(ifp)) {
spin_lock_bh(&ifp->lock);
ifp->flags &= ~IFA_F_TENTATIVE;
spin_unlock_bh(&ifp->lock);
@@ -1674,7 +1709,7 @@
struct inet6_ifaddr * ifp;

ifp = ipv6_add_addr(idev, addr, 64, IFA_LINK, IFA_F_PERMANENT);
- if (ifp) {
+ if (!IS_ERR(ifp)) {
addrconf_dad_start(ifp);
in6_ifa_put(ifp);
}

-- 
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@linux-ipv6.org>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA
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