[PATCH 4.9 21/48] net-procfs: show net devices bound packet types

Greg Kroah-Hartman
2022-02-07T11:13:59Z

From: Jianguo Wu <wujianguo@chinatelecom.cn>

commit 1d10f8a1f40b965d449e8f2d5ed7b96a7c138b77 upstream.

After commit:7866a621043f ("dev: add per net_device packet type chains"),
we can not get packet types that are bound to a specified net device by
/proc/net/ptype, this patch fix the regression.

Run "tcpdump -i ens192 udp -nns0" Before and after apply this patch:

Before:
[root@localhost ~]# cat /proc/net/ptype
Type Device Function
0800 ip_rcv
0806 arp_rcv
86dd ipv6_rcv

After:
[root@localhost ~]# cat /proc/net/ptype
Type Device Function
ALL ens192 tpacket_rcv
0800 ip_rcv
0806 arp_rcv
86dd ipv6_rcv

v1 -> v2:
- fix the regression rather than adding new /proc API as
suggested by Stephen Hemminger.

Fixes: 7866a621043f ("dev: add per net_device packet type chains")
Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/core/net-procfs.c | 35 ++++++++++++++++++++++++++++++++---
1 file changed, 32 insertions(+), 3 deletions(-)

--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -208,12 +208,23 @@ static const struct file_operations soft
.release = seq_release,
};

-static void *ptype_get_idx(loff_t pos)
+static void *ptype_get_idx(struct seq_file *seq, loff_t pos)
{
+ struct list_head *ptype_list = NULL;
struct packet_type *pt = NULL;
+ struct net_device *dev;
loff_t i = 0;
int t;

+ for_each_netdev_rcu(seq_file_net(seq), dev) {
+ ptype_list = &dev->ptype_all;
+ list_for_each_entry_rcu(pt, ptype_list, list) {
+ if (i == pos)
+ return pt;
+ ++i;
+ }
+ }
+
list_for_each_entry_rcu(pt, &ptype_all, list) {
if (i == pos)
return pt;
@@ -234,22 +245,40 @@ static void *ptype_seq_start(struct seq_
__acquires(RCU)
{
rcu_read_lock();
- return *pos ? ptype_get_idx(*pos - 1) : SEQ_START_TOKEN;
+ return *pos ? ptype_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
}

static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
+ struct net_device *dev;
struct packet_type *pt;
struct list_head *nxt;
int hash;

++*pos;
if (v == SEQ_START_TOKEN)
- return ptype_get_idx(0);
+ return ptype_get_idx(seq, 0);

pt = v;
nxt = pt->list.next;
+ if (pt->dev) {
+ if (nxt != &pt->dev->ptype_all)
+ goto found;
+
+ dev = pt->dev;
+ for_each_netdev_continue_rcu(seq_file_net(seq), dev) {
+ if (!list_empty(&dev->ptype_all)) {
+ nxt = dev->ptype_all.next;
+ goto found;
+ }
+ }
+
+ nxt = ptype_all.next;
+ goto ptype_all;
+ }
+
if (pt->type == htons(ETH_P_ALL)) {
+ptype_all:
if (nxt != &ptype_all)
goto found;
hash = 0;