From: Xin Long <lucien.xin@gmail.com>
To: Paolo Abeni <pabeni@redhat.com>
Cc: network dev <netdev@vger.kernel.org>,
quic@lists.linux.dev, davem@davemloft.net, kuba@kernel.org,
Eric Dumazet <edumazet@google.com>,
Simon Horman <horms@kernel.org>,
Stefan Metzmacher <metze@samba.org>,
Moritz Buhl <mbuhl@openbsd.org>,
Tyler Fanelli <tfanelli@redhat.com>,
Pengtao He <hepengtao@xiaomi.com>,
Thomas Dreibholz <dreibh@simula.no>,
linux-cifs@vger.kernel.org, Steve French <smfrench@gmail.com>,
Namjae Jeon <linkinjeon@kernel.org>,
Paulo Alcantara <pc@manguebit.com>, Tom Talpey <tom@talpey.com>,
kernel-tls-handshake@lists.linux.dev,
Chuck Lever <chuck.lever@oracle.com>,
Jeff Layton <jlayton@kernel.org>,
Steve Dickson <steved@redhat.com>,
Hannes Reinecke <hare@suse.de>,
Alexander Aring <aahringo@redhat.com>,
David Howells <dhowells@redhat.com>,
Matthieu Baerts <matttbe@kernel.org>,
John Ericson <mail@johnericson.me>,
Cong Wang <xiyou.wangcong@gmail.com>,
"D . Wythe" <alibuda@linux.alibaba.com>,
Jason Baron <jbaron@akamai.com>,
illiliti <illiliti@protonmail.com>,
Sabrina Dubroca <sd@queasysnail.net>,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
Daniel Stenberg <daniel@haxx.se>,
Andy Gospodarek <andrew.gospodarek@broadcom.com>
Subject: Re: [PATCH net-next v7 08/16] quic: add path management
Date: Tue, 20 Jan 2026 16:06:53 -0500 [thread overview]
Message-ID: <CADvbK_chN0KTnibDW6VL3pR4iPQqrHznDXYCUDneB=vEnVD0MA@mail.gmail.com> (raw)
In-Reply-To: <CADvbK_dYbMa-nVi_8M-XS1QcVUw25t4CZdvcq_HcACx38bH86g@mail.gmail.com>
On Tue, Jan 20, 2026 at 10:34 AM Xin Long <lucien.xin@gmail.com> wrote:
>
> On Tue, Jan 20, 2026 at 9:13 AM Paolo Abeni <pabeni@redhat.com> wrote:
> >
> > On 1/15/26 4:11 PM, Xin Long wrote:
> > > @@ -0,0 +1,524 @@
> > > +// SPDX-License-Identifier: GPL-2.0-or-later
> > > +/* QUIC kernel implementation
> > > + * (C) Copyright Red Hat Corp. 2023
> > > + *
> > > + * This file is part of the QUIC kernel implementation
> > > + *
> > > + * Initialization/cleanup for QUIC protocol support.
> > > + *
> > > + * Written or modified by:
> > > + * Xin Long <lucien.xin@gmail.com>
> > > + */
> > > +
> > > +#include <net/udp_tunnel.h>
> > > +#include <linux/quic.h>
> > > +
> > > +#include "common.h"
> > > +#include "family.h"
> > > +#include "path.h"
> > > +
> > > +static int (*quic_path_rcv)(struct sock *sk, struct sk_buff *skb, u8 err);
> >
> > It's unclear why an indirect call is needed here. At least some
> > explanation is needed in the commit message, possibly you could call
> > directly a static function.
> >
> This patchset makes the path subcomponent more independent from the core
> implementation. Aside from a few shared helper functions, it doesn't
> rely on code outside the subcomponent, in particular socket.c and
> packet.c.
>
> Other subcomponents, such as stream, connid, pnspace, cong,
> crypto, common, and family follow the same approach. They expose
> APIs to the core QUIC logic and don’t see the main process.
>
> Will leave an explanation here.
>
To achieve this, instead of introducing an indirect call, we can use
an 'extern' declaration of quic_packet_rcv() once it is introduced.
Before that point, the code simply falls back to calling kfree_skb(skb).
Will update it.
Thanks.
> > > +
> > > +static int quic_udp_rcv(struct sock *sk, struct sk_buff *skb)
> > > +{
> > > + memset(skb->cb, 0, sizeof(skb->cb));
> > > + QUIC_SKB_CB(skb)->seqno = -1;
> > > + QUIC_SKB_CB(skb)->time = quic_ktime_get_us();
> > > +
> > > + skb_pull(skb, sizeof(struct udphdr));
> > > + skb_dst_force(skb);
> > > + quic_path_rcv(sk, skb, 0);
> > > + return 0;
> >
> > Why not:
> > return quic_path_rcv(sk, skb, 0);
> > ?
> I checked the udp tunnel users:
>
> - bareudp: bareudp_udp_encap_recv()
> - vxlan: vxlan_rcv()
> - geneve: geneve_udp_encap_recv()
> - tipc: tipc_udp_recv()
> - sctp: sctp_udp_rcv()
>
> they all are returning 0 in .encap_udp(), I think because they all
> take care of the
> skb freeing in their err path already.
>
> is it safe to return error to UDP stack if the skb is already freed?
> Do you know?
>
> >
> > > +static struct quic_udp_sock *quic_udp_sock_create(struct sock *sk, union quic_addr *a)
> > > +{
> > > + struct udp_tunnel_sock_cfg tuncfg = {};
> > > + struct udp_port_cfg udp_conf = {};
> > > + struct net *net = sock_net(sk);
> > > + struct quic_uhash_head *head;
> > > + struct quic_udp_sock *us;
> > > + struct socket *sock;
> > > +
> > > + us = kzalloc(sizeof(*us), GFP_KERNEL);
> > > + if (!us)
> > > + return NULL;
> > > +
> > > + quic_udp_conf_init(sk, &udp_conf, a);
> > > + if (udp_sock_create(net, &udp_conf, &sock)) {
> > > + pr_debug("%s: failed to create udp sock\n", __func__);
> > > + kfree(us);
> > > + return NULL;
> > > + }
> > > +
> > > + tuncfg.encap_type = 1;
> > > + tuncfg.encap_rcv = quic_udp_rcv;
> > > + tuncfg.encap_err_lookup = quic_udp_err;
> > > + setup_udp_tunnel_sock(net, sock, &tuncfg);
> > > +
> > > + refcount_set(&us->refcnt, 1);
> > > + us->sk = sock->sk;
> > > + memcpy(&us->addr, a, sizeof(*a));
> > > + us->bind_ifindex = sk->sk_bound_dev_if;
> > > +
> > > + head = quic_udp_sock_head(net, ntohs(a->v4.sin_port));
> > > + hlist_add_head(&us->node, &head->head);
> > > + INIT_WORK(&us->work, quic_udp_sock_put_work);
> > > +
> > > + return us;
> > > +}
> > > +
> > > +static bool quic_udp_sock_get(struct quic_udp_sock *us)
> > > +{
> > > + return refcount_inc_not_zero(&us->refcnt);
> > > +}
> > > +
> > > +static void quic_udp_sock_put(struct quic_udp_sock *us)
> > > +{
> > > + if (refcount_dec_and_test(&us->refcnt))
> > > + queue_work(quic_wq, &us->work);
> >
> > Why using a workqueue here? AFAICS all the caller are in process
> > context. Is that to break a possible deadlock due to nested mutex?
> > Likely a comment on the refcount/locking scheme would help.
> >
> quic_udp_sock_put() will also be called in the RX path via
> quic_path_unbind() for the connection migration (after changing
> to a new path.), which is in the patchset-2.
>
> I will leave a comment for an explanation here.
>
> Thanks.
next prev parent reply other threads:[~2026-01-20 21:07 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-15 15:11 [PATCH net-next v7 00/16] net: introduce QUIC infrastructure and core subcomponents Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 01/16] net: define IPPROTO_QUIC and SOL_QUIC constants Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 02/16] net: build socket infrastructure for QUIC protocol Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 03/16] quic: provide common utilities and data structures Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 04/16] quic: provide family ops for address and protocol Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 05/16] quic: provide quic.h header files for kernel and userspace Xin Long
2026-01-20 12:23 ` Paolo Abeni
2026-01-15 15:11 ` [PATCH net-next v7 06/16] quic: add stream management Xin Long
2026-01-20 12:31 ` Paolo Abeni
2026-01-20 14:58 ` Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 07/16] quic: add connection id management Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 08/16] quic: add path management Xin Long
2026-01-20 14:13 ` Paolo Abeni
2026-01-20 15:34 ` Xin Long
2026-01-20 21:06 ` Xin Long [this message]
2026-01-15 15:11 ` [PATCH net-next v7 09/16] quic: add congestion control Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 10/16] quic: add packet number space Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 11/16] quic: add crypto key derivation and installation Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 12/16] quic: add crypto packet encryption and decryption Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 13/16] quic: add timer management Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 14/16] quic: add frame encoder and decoder base Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 15/16] quic: add packet builder base Xin Long
2026-01-20 14:31 ` Paolo Abeni
2026-01-20 16:07 ` Xin Long
2026-01-15 15:11 ` [PATCH net-next v7 16/16] quic: add packet parser base Xin Long
2026-01-16 16:20 ` Stefan Metzmacher
2026-01-16 19:55 ` Xin Long
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