[PATCH net 3/3] ovpn: fix VPN TX bytes counting

[Antonio Quartulli <antonio@openvpn.net>]

From: Ralf Lici <ralf@mandelbit.com>

In ovpn_net_xmit, after GSO segmentation and segment processing, the
first segment on the list is used to increment VPN TX statistics, which
fails to account for any subsequent segments in the chain.

Fix this by accumulating the length of every segment that successfully
passes skb_share_check into a tx_bytes variable. This ensures the peer
statistics accurately reflect the total data volume sent, regardless of
whether the original packet was segmented.

Fixes: 04ca14955f9a ("ovpn: store tunnel and transport statistics")
Signed-off-by: Ralf Lici <ralf@mandelbit.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
---
 drivers/net/ovpn/io.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ovpn/io.c b/drivers/net/ovpn/io.c
index f70c58b10599..955c9a37e1f8 100644
--- a/drivers/net/ovpn/io.c
+++ b/drivers/net/ovpn/io.c
@@ -355,6 +355,7 @@ netdev_tx_t ovpn_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct ovpn_priv *ovpn = netdev_priv(dev);
 	struct sk_buff *segments, *curr, *next;
 	struct sk_buff_head skb_list;
+	unsigned int tx_bytes = 0;
 	struct ovpn_peer *peer;
 	__be16 proto;
 	int ret;
@@ -414,6 +415,8 @@ netdev_tx_t ovpn_net_xmit(struct sk_buff *skb, struct net_device *dev)
 			continue;
 		}
 
+		/* only count what we actually send */
+		tx_bytes += curr->len;
 		__skb_queue_tail(&skb_list, curr);
 	}
 
@@ -426,7 +429,7 @@ netdev_tx_t ovpn_net_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 	skb_list.prev->next = NULL;
 
-	ovpn_peer_stats_increment_tx(&peer->vpn_stats, skb_list.next->len);
+	ovpn_peer_stats_increment_tx(&peer->vpn_stats, tx_bytes);
 	ovpn_send(ovpn, skb_list.next, peer);
 
 	return NETDEV_TX_OK;
-- 
2.52.0