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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EunNC8rt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EunNC8rt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F040FC4CEC5; Mon, 9 Sep 2024 11:57:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725883034; bh=Xs1ma3py/kYQl+X+Z1t4uxsWvuP6OYkETY78e8ZgRGc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=EunNC8rtl0pHf0fMNVqfew4abZDFXZd9Euf//3xorzLJsPEwXXptrJEaFFooTq02+ Ma2/HmtZh1BMoT4o8sv5QX11wBFvdgnPQXU8RnoTqFnfWrrjqPuT2v9C7ZqLSu2ZDH V36dsM8KBFh2LX/tBIBiIR1ktKXLy46DtofdSCK7SQaLjdgp4eJPloF8KISw6WtyCD RvIEkolAxl9RdRvVW+sAaaDQXm/ye1y/Di+qQw/xPwh9wSBkC3u3WNQmun9NOHbk5I PgFxaDItCfAV5eZkd8yAGNfdL82IGPHFHU6Zqf8jwXm5UuQGkDp6EegE6GKhUxftm7 6X7v/r4x2JtSA== Message-ID: <332e79e8eb212de91c848ef0d99a2f3326a8153f.camel@kernel.org> Subject: Re: [PATCH mptcp-next v2 1/4] bpf: Add mptcp_subflow bpf_iter From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang , bpf , Martin KaFai Lau Date: Mon, 09 Sep 2024 19:57:10 +0800 In-Reply-To: References: Autocrypt: addr=geliang@kernel.org; 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charset="UTF-8" User-Agent: Evolution 3.52.3-0ubuntu1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, 2024-09-09 at 09:36 +0800, Geliang Tang wrote: > From: Geliang Tang > > It's necessary to traverse all subflows on the conn_list of an MPTCP > socket and then call kfunc to modify the fields of each subflow. In > kernel space, mptcp_for_each_subflow() helper is used for this: > > mptcp_for_each_subflow(msk, subflow) > kfunc(subflow); > > But in the MPTCP BPF program, this has not yet been implemented. As > Martin suggested recently, this conn_list walking + modify-by-kfunc > usage fits the bpf_iter use case. So this patch adds a new bpf_iter > type named "mptcp_subflow" to do this and implements its helpers > bpf_iter_mptcp_subflow_new()/_next()/_destroy(). > > Then bpf_for_each() for mptcp_subflow can be used in BPF program like > this: > > bpf_rcu_read_lock(); > bpf_for_each(mptcp_subflow, subflow, msk) > kfunc(subflow); > bpf_rcu_read_unlock(); > > Suggested-by: Martin KaFai Lau > Signed-off-by: Geliang Tang > --- >  net/mptcp/bpf.c      | 51 > ++++++++++++++++++++++++++++++++++++++++++++ >  net/mptcp/protocol.h |  6 ++++++ >  2 files changed, 57 insertions(+) > > diff --git a/net/mptcp/bpf.c b/net/mptcp/bpf.c > index 9672a70c24b0..799264119891 100644 > --- a/net/mptcp/bpf.c > +++ b/net/mptcp/bpf.c > @@ -204,10 +204,59 @@ static const struct btf_kfunc_id_set > bpf_mptcp_fmodret_set = { >   .set   = &bpf_mptcp_fmodret_ids, >  }; >   > +struct bpf_iter__mptcp_subflow { > + __bpf_md_ptr(struct bpf_iter_meta *, meta); > + __bpf_md_ptr(struct mptcp_sock *, msk); > + __bpf_md_ptr(struct list_head *, pos); > +}; This bpf_iter__mptcp_subflow struct should be dropped too. > + > +struct bpf_iter_mptcp_subflow { > + __u64 __opaque[2]; > +} __attribute__((aligned(8))); > + > +struct bpf_iter_mptcp_subflow_kern { > + struct mptcp_sock *msk; > + struct list_head *pos; > +} __attribute__((aligned(8))); > + >  __diag_push(); >  __diag_ignore_all("-Wmissing-prototypes", >     "kfuncs which will be used in BPF programs"); Duplicate with __bpf_kfunc_start_defs/__bpf_kfunc_end_defs, __diag_push, __diag_pop and __diag_ignore_all should be dropped. >   > +__bpf_kfunc_start_defs(); > + > +__bpf_kfunc int bpf_iter_mptcp_subflow_new(struct > bpf_iter_mptcp_subflow *it, > +    struct mptcp_sock *msk) > +{ > + struct bpf_iter_mptcp_subflow_kern *kit = (void *)it; > + > + if (!msk) > + return -EINVAL; > + > + kit->msk = msk; > + kit->pos = &msk->conn_list; > + return 0; > +} > + > +__bpf_kfunc struct mptcp_subflow_context * > +bpf_iter_mptcp_subflow_next(struct bpf_iter_mptcp_subflow *it) > +{ > + struct bpf_iter_mptcp_subflow_kern *kit = (void *)it; > + struct mptcp_subflow_context *subflow; > + struct mptcp_sock *msk = kit->msk; > + > + subflow = list_entry((kit->pos)->next, struct > mptcp_subflow_context, node); > + if (!msk || list_entry_is_head(subflow, &msk->conn_list, > node)) > + return NULL; > + > + kit->pos = &subflow->node; > + return subflow; > +} > + > +__bpf_kfunc void bpf_iter_mptcp_subflow_destroy(struct > bpf_iter_mptcp_subflow *it) > +{ > +} > + >  __bpf_kfunc struct mptcp_subflow_context * >  bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, > unsigned int pos) >  { > @@ -221,6 +270,8 @@ __bpf_kfunc bool > bpf_mptcp_subflow_queues_empty(struct sock *sk) >   return tcp_rtx_queue_empty(sk); >  } >   > +__bpf_kfunc_end_defs(); > + >  __diag_pop(); >   >  BTF_KFUNCS_START(bpf_mptcp_sched_kfunc_ids) > diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h > index d25d2dac88a5..b3f5254e3c0d 100644 > --- a/net/mptcp/protocol.h > +++ b/net/mptcp/protocol.h > @@ -715,6 +715,12 @@ void mptcp_subflow_queue_clean(struct sock *sk, > struct sock *ssk); >  void mptcp_sock_graft(struct sock *sk, struct socket *parent); >  u64 mptcp_wnd_end(const struct mptcp_sock *msk); >  void mptcp_set_timeout(struct sock *sk); > +struct bpf_iter_mptcp_subflow; > +int bpf_iter_mptcp_subflow_new(struct bpf_iter_mptcp_subflow *it, > +        struct mptcp_sock *msk); > +struct mptcp_subflow_context * > +bpf_iter_mptcp_subflow_next(struct bpf_iter_mptcp_subflow *it); > +void bpf_iter_mptcp_subflow_destroy(struct bpf_iter_mptcp_subflow > *it); No need to add these declarations, since "-Wmissing-declarations" is ignored in __bpf_kfunc_start_defs. Will update in v3. Thanks, -Geliang >  bool bpf_mptcp_subflow_queues_empty(struct sock *sk); >  struct mptcp_subflow_context * >  bpf_mptcp_subflow_ctx_by_pos(const struct mptcp_sched_data *data, > unsigned int pos);