[PATCH v2] Allow ipv6 proxies and arp proxies be shown with iproute2

[PATCH v2] Allow ipv6 proxies and arp proxies be shown with iproute2

[Tony Zelenoff]

Add ability to return neighbour proxies list to caller if
it sent full ndmsg structure and has NTF_PROXY flag set.

Before this patch (and before iproute2 patches):
$ ip neigh add proxy 2001::1 dev eth0
$ ip -6 neigh show
$

After it and with applied iproute2 patches:
$ ip neigh add proxy 2001::1 dev eth0
$ ip -6 neigh show
2001::1 dev eth0  proxy
$

Compatibility with old versions of iproute2 is not broken,
kernel checks for incoming structure size and properly
works if old structure is came.

[v2]
* changed comments style.
* removed useless line with continue and curly bracket.
* changed incoming message size check from equal to more or
  equal.

CC: davem@davemloft.net
CC: kuznet@ms2.inr.ac.ru
CC: netdev@vger.kernel.org
CC: xemul@parallels.com
Signed-off-by: Tony Zelenoff <antonz@parallels.com>
---
 net/core/neighbour.c |   90 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 87 insertions(+), 3 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 6dbcf51..a022072 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2111,6 +2111,35 @@ nla_put_failure:
 	return -EMSGSIZE;
 }
 
+static int pneigh_fill_info(struct sk_buff *skb, struct pneigh_entry *pn,
+			    u32 pid, u32 seq, int type, unsigned int flags,
+			    struct neigh_table *tbl)
+{
+	struct nlmsghdr *nlh;
+	struct ndmsg *ndm;
+
+	nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
+	if (nlh == NULL)
+		return -EMSGSIZE;
+
+	ndm = nlmsg_data(nlh);
+	ndm->ndm_family	 = tbl->family;
+	ndm->ndm_pad1    = 0;
+	ndm->ndm_pad2    = 0;
+	ndm->ndm_flags	 = pn->flags | NTF_PROXY;
+	ndm->ndm_type	 = NDA_DST;
+	ndm->ndm_ifindex = pn->dev->ifindex;
+	ndm->ndm_state	 = NUD_NONE;
+
+	NLA_PUT(skb, NDA_DST, tbl->key_len, pn->key);
+
+	return nlmsg_end(skb, nlh);
+
+nla_put_failure:
+	nlmsg_cancel(skb, nlh);
+	return -EMSGSIZE;
+}
+
 static void neigh_update_notify(struct neighbour *neigh)
 {
 	call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, neigh);
@@ -2156,23 +2185,78 @@ out:
 	return rc;
 }
 
+static int pneigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
+			     struct netlink_callback *cb)
+{
+	struct pneigh_entry *n;
+	struct net *net = sock_net(skb->sk);
+	int rc, h, s_h = cb->args[3];
+	int idx, s_idx = idx = cb->args[4];
+
+	read_lock_bh(&tbl->lock);
+
+	for (h = 0; h <= PNEIGH_HASHMASK; h++) {
+		if (h < s_h)
+			continue;
+		if (h > s_h)
+			s_idx = 0;
+		for (n = tbl->phash_buckets[h], idx = 0; n; n = n->next) {
+			if (dev_net(n->dev) != net)
+				continue;
+			if (idx < s_idx)
+				goto next;
+			if (pneigh_fill_info(skb, n, NETLINK_CB(cb->skb).pid,
+					    cb->nlh->nlmsg_seq,
+					    RTM_NEWNEIGH,
+					    NLM_F_MULTI, tbl) <= 0) {
+				read_unlock_bh(&tbl->lock);
+				rc = -1;
+				goto out;
+			}
+		next:
+			idx++;
+		}
+	}
+
+	read_unlock_bh(&tbl->lock);
+	rc = skb->len;
+out:
+	cb->args[3] = h;
+	cb->args[4] = idx;
+	return rc;
+
+}
+
 static int neigh_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct neigh_table *tbl;
 	int t, family, s_t;
+	int proxy = 0;
+	int err = 0;
 
 	read_lock(&neigh_tbl_lock);
 	family = ((struct rtgenmsg *) nlmsg_data(cb->nlh))->rtgen_family;
+
+	/* check for full ndmsg structure presence, family member is
+	 * the same for both structures
+	 */
+	if (nlmsg_len(cb->nlh) >= sizeof(struct ndmsg) &&
+	    ((struct ndmsg *) nlmsg_data(cb->nlh))->ndm_flags == NTF_PROXY)
+		proxy = 1;
+
 	s_t = cb->args[0];
 
-	for (tbl = neigh_tables, t = 0; tbl; tbl = tbl->next, t++) {
+	for (tbl = neigh_tables, t = 0; tbl && (err >= 0);
+	     tbl = tbl->next, t++) {
 		if (t < s_t || (family && tbl->family != family))
 			continue;
 		if (t > s_t)
 			memset(&cb->args[1], 0, sizeof(cb->args) -
 						sizeof(cb->args[0]));
-		if (neigh_dump_table(tbl, skb, cb) < 0)
-			break;
+		if (proxy)
+			err = pneigh_dump_table(tbl, skb, cb);
+		else
+			err = neigh_dump_table(tbl, skb, cb);
 	}
 	read_unlock(&neigh_tbl_lock);
 
-- 
1.7.1

Re: [PATCH v2] Allow ipv6 proxies and arp proxies be shown with iproute2

[Thomas Graf]

On Fri, Jan 27, 2012 at 12:28:58PM +0400, Tony Zelenoff wrote:
> Add ability to return neighbour proxies list to caller if
> it sent full ndmsg structure and has NTF_PROXY flag set.
> 
> Before this patch (and before iproute2 patches):
> $ ip neigh add proxy 2001::1 dev eth0
> $ ip -6 neigh show
> $
> 
> After it and with applied iproute2 patches:
> $ ip neigh add proxy 2001::1 dev eth0
> $ ip -6 neigh show
> 2001::1 dev eth0  proxy
> $
> 
> Compatibility with old versions of iproute2 is not broken,
> kernel checks for incoming structure size and properly
> works if old structure is came.
> 
> [v2]
> * changed comments style.
> * removed useless line with continue and curly bracket.
> * changed incoming message size check from equal to more or
>   equal.
> 
> CC: davem@davemloft.net
> CC: kuznet@ms2.inr.ac.ru
> CC: netdev@vger.kernel.org
> CC: xemul@parallels.com
> Signed-off-by: Tony Zelenoff <antonz@parallels.com>

Acked-by: Thomas Graf <tgraf@suug.ch>

Re: [PATCH v2] Allow ipv6 proxies and arp proxies be shown with iproute2

[David Miller]

From: Thomas Graf <tgraf@infradead.org>
Date: Fri, 27 Jan 2012 05:35:21 -0500

> On Fri, Jan 27, 2012 at 12:28:58PM +0400, Tony Zelenoff wrote:
>> Add ability to return neighbour proxies list to caller if
>> it sent full ndmsg structure and has NTF_PROXY flag set.
>> 
>> Before this patch (and before iproute2 patches):
>> $ ip neigh add proxy 2001::1 dev eth0
>> $ ip -6 neigh show
>> $
>> 
>> After it and with applied iproute2 patches:
>> $ ip neigh add proxy 2001::1 dev eth0
>> $ ip -6 neigh show
>> 2001::1 dev eth0  proxy
>> $
>> 
>> Compatibility with old versions of iproute2 is not broken,
>> kernel checks for incoming structure size and properly
>> works if old structure is came.
>> 
>> [v2]
>> * changed comments style.
>> * removed useless line with continue and curly bracket.
>> * changed incoming message size check from equal to more or
>>   equal.
>> 
>> CC: davem@davemloft.net
>> CC: kuznet@ms2.inr.ac.ru
>> CC: netdev@vger.kernel.org
>> CC: xemul@parallels.com
>> Signed-off-by: Tony Zelenoff <antonz@parallels.com>
> 
> Acked-by: Thomas Graf <tgraf@suug.ch>

Applied, thanks.