Re: [PATCH net-next v24 07/23] ovpn: implement basic TX path (UDP)

2025-03-18, 02:40:42 +0100, Antonio Quartulli wrote:

+static int ovpn_udp_output(struct ovpn_peer *peer, struct dst_cache *cache,

• 	   struct sock *sk, struct sk_buff *skb)
  

+{

• struct ovpn_bind *bind;
• int ret;
• /* set sk to null if skb is already orphaned */
• if (!skb->destructor)

• skb->sk = NULL;
  

• /* always permit openvpn-created packets to be (outside) fragmented */
• skb->ignore_df = 1;

Have you tested this with IPv4 encap? AFAICT it doesn't have any effect because of the call chain:

ovpn_udp4_output -> udp_tunnel_xmit_skb -> iptunnel_xmit -> skb_scrub_packet

which does

skb->ignore_df = 0;

But since you pass df = 0 to udp_tunnel_xmit_skb, I suspect it works as intended despite skb_scrub_packet.

[note: that was the last comment I wanted to send, I have a few more suggestions that don't need to be addressed at this time]

• rcu_read_lock();
• bind = rcu_dereference(peer->bind);
• if (unlikely(!bind)) {

• net_warn_ratelimited("%s: no bind for remote peer %u\n",
  

• 		     netdev_name(peer->ovpn->dev), peer->id);
  

• ret = -ENODEV;
  

• goto out;
  

• }
• switch (bind->remote.in4.sin_family) {
• case AF_INET:

• ret = ovpn_udp4_output(peer, bind, cache, sk, skb);
  

• break;
  

+#if IS_ENABLED(CONFIG_IPV6)

• case AF_INET6:

• ret = ovpn_udp6_output(peer, bind, cache, sk, skb);
  

• break;
  

+#endif

• default:

• ret = -EAFNOSUPPORT;
  

• break;
  

• }

+out:

• rcu_read_unlock();
• return ret;

+}