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Message-Id: <1424756572-29379-1-git-send-email-roopa@cumulusnetworks.com>
Date: Mon, 23 Feb 2015 21:42:52 -0800
From: roopa@...ulusnetworks.com
To: hadi@...atatu.com
Cc: netdev@...r.kernel.org, davem@...emloft.net,
hannes@...essinduktion.org
Subject: [PATCH net-next RFC] ipv4 neigh: match add/del dev lookup behaviour to SIOCSARP/SIOCDARP
From: Roopa Prabhu <roopa@...ulusnetworks.com>
Today neigh adds and dels using the netlink RTM_NEWNEIGH/RTM_DELNEIGH
messages require dst device to be specified. The equivalent ipv4 neigh
entry add/del using SIOCSARP/SIOCDARP does not require a device. It finds
the dst dev by doing a route lookup (ip_route_output).
This patch tries to match netlink ipv4 neigh add/del behaviour with
SIOCSARP/SIOCDARP for the case where user does not specify a device.
If user has not specified a dst device, it looks for the device via a
route lookup. If the route lookup fails, the behaviour is unchanged,
the user will get an -EINVAL as before
(This can be changed to return -ENODEV if needed. This patch leaves it at
-EINVAL to match current behaviour).
Testing this change requires an iproute2 patch to make dev optional
during ipv4 neigh adds/dels.
Reported-by: Jamal Hadi Salim <hadi@...atatu.com>
Suggested-by: Jamal Hadi Salim <hadi@...atatu.com>
Signed-off-by: Roopa Prabhu <roopa@...ulusnetworks.com>
---
net/core/neighbour.c | 54 +++++++++++++++++++++++++++++++++-----------------
1 file changed, 36 insertions(+), 18 deletions(-)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 70fe9e1..3fa2602 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -29,6 +29,7 @@
#endif
#include <linux/times.h>
#include <net/net_namespace.h>
+#include <net/route.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/sock.h>
@@ -1622,6 +1623,7 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
struct neighbour *neigh;
struct net_device *dev = NULL;
int err = -EINVAL;
+ void *dst;
ASSERT_RTNL();
if (nlmsg_len(nlh) < sizeof(*ndm))
@@ -1632,30 +1634,39 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh)
goto out;
ndm = nlmsg_data(nlh);
+ tbl = neigh_find_table(ndm->ndm_family);
+ if (tbl == NULL)
+ return -EAFNOSUPPORT;
+
+ if (nla_len(dst_attr) < tbl->key_len)
+ goto out;
+
+ dst = nla_data(dst_attr);
if (ndm->ndm_ifindex) {
dev = __dev_get_by_index(net, ndm->ndm_ifindex);
if (dev == NULL) {
err = -ENODEV;
goto out;
}
- }
+ } else if (ndm->ndm_family == AF_INET) {
+ struct rtable *rt;
- tbl = neigh_find_table(ndm->ndm_family);
- if (tbl == NULL)
- return -EAFNOSUPPORT;
-
- if (nla_len(dst_attr) < tbl->key_len)
- goto out;
+ rt = ip_route_output(net, *(__be32 *)dst, 0, RTO_ONLINK, 0);
+ if (!IS_ERR(rt)) {
+ dev = rt->dst.dev;
+ ip_rt_put(rt);
+ }
+ }
if (ndm->ndm_flags & NTF_PROXY) {
- err = pneigh_delete(tbl, net, nla_data(dst_attr), dev);
+ err = pneigh_delete(tbl, net, dst, dev);
goto out;
}
if (dev == NULL)
goto out;
- neigh = neigh_lookup(tbl, nla_data(dst_attr), dev);
+ neigh = neigh_lookup(tbl, dst, dev);
if (neigh == NULL) {
err = -ENOENT;
goto out;
@@ -1692,24 +1703,31 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh)
goto out;
ndm = nlmsg_data(nlh);
+ tbl = neigh_find_table(ndm->ndm_family);
+ if (tbl == NULL)
+ return -EAFNOSUPPORT;
+
+ if (nla_len(tb[NDA_DST]) < tbl->key_len)
+ goto out;
+
+ dst = nla_data(tb[NDA_DST]);
if (ndm->ndm_ifindex) {
dev = __dev_get_by_index(net, ndm->ndm_ifindex);
if (dev == NULL) {
err = -ENODEV;
goto out;
}
+ } else if (ndm->ndm_family == AF_INET) {
+ struct rtable *rt;
- if (tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len)
- goto out;
+ rt = ip_route_output(net, *(__be32 *)dst, 0, RTO_ONLINK, 0);
+ if (!IS_ERR(rt)) {
+ dev = rt->dst.dev;
+ ip_rt_put(rt);
+ }
}
-
- tbl = neigh_find_table(ndm->ndm_family);
- if (tbl == NULL)
- return -EAFNOSUPPORT;
-
- if (nla_len(tb[NDA_DST]) < tbl->key_len)
+ if (dev && tb[NDA_LLADDR] && nla_len(tb[NDA_LLADDR]) < dev->addr_len)
goto out;
- dst = nla_data(tb[NDA_DST]);
lladdr = tb[NDA_LLADDR] ? nla_data(tb[NDA_LLADDR]) : NULL;
if (ndm->ndm_flags & NTF_PROXY) {
--
1.7.10.4
--
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