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net: Add support for filtering neigh dump by master device
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Add support for filtering neighbor dumps by master device by adding
the NDA_MASTER attribute to the dump request. A new netlink flag,
NLM_F_DUMP_FILTERED, is added to indicate the kernel supports the
request and output is filtered as requested.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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David Ahern authored and davem330 committed Sep 30, 2015
1 parent 5172393 commit 21fdd09
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Showing 2 changed files with 32 additions and 1 deletion.
1 change: 1 addition & 0 deletions include/uapi/linux/netlink.h
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@ struct nlmsghdr {
#define NLM_F_ACK 4 /* Reply with ack, with zero or error code */
#define NLM_F_ECHO 8 /* Echo this request */
#define NLM_F_DUMP_INTR 16 /* Dump was inconsistent due to sequence change */
#define NLM_F_DUMP_FILTERED 32 /* Dump was filtered as requested */

/* Modifiers to GET request */
#define NLM_F_ROOT 0x100 /* specify tree root */
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32 changes: 31 additions & 1 deletion net/core/neighbour.c
Original file line number Diff line number Diff line change
Expand Up @@ -2235,14 +2235,42 @@ static void neigh_update_notify(struct neighbour *neigh)
__neigh_notify(neigh, RTM_NEWNEIGH, 0);
}

static bool neigh_master_filtered(struct net_device *dev, int master_idx)
{
struct net_device *master;

if (!master_idx)
return false;

master = netdev_master_upper_dev_get(dev);
if (!master || master->ifindex != master_idx)
return true;

return false;
}

static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
const struct nlmsghdr *nlh = cb->nlh;
struct nlattr *tb[NDA_MAX + 1];
struct neighbour *n;
int rc, h, s_h = cb->args[1];
int idx, s_idx = idx = cb->args[2];
struct neigh_hash_table *nht;
int filter_master_idx = 0;
unsigned int flags = NLM_F_MULTI;
int err;

err = nlmsg_parse(nlh, sizeof(struct ndmsg), tb, NDA_MAX, NULL);
if (!err) {
if (tb[NDA_MASTER])
filter_master_idx = nla_get_u32(tb[NDA_MASTER]);

if (filter_master_idx)
flags |= NLM_F_DUMP_FILTERED;
}

rcu_read_lock_bh();
nht = rcu_dereference_bh(tbl->nht);
Expand All @@ -2255,12 +2283,14 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
n = rcu_dereference_bh(n->next)) {
if (!net_eq(dev_net(n->dev), net))
continue;
if (neigh_master_filtered(n->dev, filter_master_idx))
continue;
if (idx < s_idx)
goto next;
if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
RTM_NEWNEIGH,
NLM_F_MULTI) < 0) {
flags) < 0) {
rc = -1;
goto out;
}
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