From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1368EC6FD20 for ; Wed, 22 Mar 2023 00:29:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229595AbjCVA3J (ORCPT ); Tue, 21 Mar 2023 20:29:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229558AbjCVA3I (ORCPT ); Tue, 21 Mar 2023 20:29:08 -0400 Received: from out-47.mta0.migadu.com (out-47.mta0.migadu.com [91.218.175.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6981D442EB for ; Tue, 21 Mar 2023 17:29:07 -0700 (PDT) Message-ID: <8d8f605d-f722-8a91-4dcf-2017cad40f7b@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1679444945; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wDC9Ih3WhES37UutzlIVGKMbYDWZZoHCLDYDz/6dnHw=; b=lTLxkvHqSyyCjBZTqmDsMVVWHkJ4bzhXa1X6YaLuYWvsKJvPp5AxHlK2AeFcgJEuFR96HK mEF0/Myj9b8unVI1CPX2L+MfLk/ipzhSdfZnBJ5Sh56v5k8UJUtvKVmlZBVXAILodz2/Yw z9LSFPgWTeFVXFCkUhXU3+Ey+v46440= Date: Tue, 21 Mar 2023 17:29:02 -0700 MIME-Version: 1.0 Subject: Re: [PATCH v3 bpf-next 4/5] [RFC] udp: Fix destroying UDP listening sockets Content-Language: en-US To: Aditi Ghag Cc: kafai@fb.com, sdf@google.com, edumazet@google.com, bpf References: <20230321184541.1857363-1-aditi.ghag@isovalent.com> <20230321184541.1857363-5-aditi.ghag@isovalent.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20230321184541.1857363-5-aditi.ghag@isovalent.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 3/21/23 11:45 AM, Aditi Ghag wrote: > Previously, UDP listening sockets that bind'ed to a port > weren't getting properly destroyed via udp_abort. > Specifically, the sockets were left in the UDP hash table with > unset source port. > Fix the issue by unconditionally unhashing and resetting source > port for sockets that are getting destroyed. This would mean > that in case of sockets listening on wildcarded address and > on a specific address with a common port, users would have to > explicitly select the socket(s) they intend to destroy. > > Signed-off-by: Aditi Ghag > --- > net/ipv4/udp.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 02d357713838..a495ac88fcee 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -1965,6 +1965,25 @@ int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) > } > EXPORT_SYMBOL(udp_pre_connect); > > +int __udp_disconnect_with_abort(struct sock *sk) > +{ > + struct inet_sock *inet = inet_sk(sk); > + > + sk->sk_state = TCP_CLOSE; > + inet->inet_daddr = 0; > + inet->inet_dport = 0; > + sock_rps_reset_rxhash(sk); > + sk->sk_bound_dev_if = 0; > + inet_reset_saddr(sk); > + inet->inet_sport = 0; > + sk_dst_reset(sk); > + /* (TBD) In case of sockets listening on wildcard and specific address > + * with a common port, socket will be removed from {hash, hash2} table. > + */ > + sk->sk_prot->unhash(sk); hmm... not sure if I understand the use case. The idea is to enforce the user space to bind() again when it gets error from read(fd) because the source ip/port needs to change when sending to another dst IP/port? Does it have a usage example in the selftests? > + return 0; > +} > + > int __udp_disconnect(struct sock *sk, int flags) > { > struct inet_sock *inet = inet_sk(sk); > @@ -2937,7 +2956,7 @@ int udp_abort(struct sock *sk, int err) > > sk->sk_err = err; > sk_error_report(sk); > - __udp_disconnect(sk, 0); > + __udp_disconnect_with_abort(sk); > > out: > if (!has_current_bpf_ctx())