From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6EDEFCA55 for ; Fri, 4 Aug 2023 20:49:27 +0000 (UTC) Received: from out-75.mta0.migadu.com (out-75.mta0.migadu.com [91.218.175.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E899810CA for ; Fri, 4 Aug 2023 13:49:24 -0700 (PDT) Message-ID: <3e38a143-b683-6368-8e76-277394155bc6@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1691182163; 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=E1eN8tOuww36HZPXLIuSgwhpOWc+BiApnQsrkjpB8Ks=; b=g7gLkCsYN/MAuFNNC+BDN7awxDKUINupinpjfY3fTYaXuKEuxAQZ51HBbu0376liiHg6X0 2RnwG2OGU0iRp80CxY7bu5SiyMKQmRa/3jx5heAtSWnN7nYPWQC69F6olNomt/z86uspBi AVvwcBeMYOESSVIERkVnQEDiJtrgFDQ= Date: Fri, 4 Aug 2023 21:49:19 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] net/ipv4: return the real errno instead of -EINVAL Content-Language: en-US To: yang.yang29@zte.com.cn, davem@davemloft.net Cc: dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <202308041648338823694@zte.com.cn> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Vadim Fedorenko In-Reply-To: <202308041648338823694@zte.com.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On 04/08/2023 09:48, yang.yang29@zte.com.cn wrote: > From: xu xin > > For now, no matter what error pointer ip_neigh_for_gw() returns, > ip_finish_output2() always return -EINVAL, which may mislead the upper > users. > > For exemple, an application uses sendto to send an UDP packet, but when the > neighbor table overflows, sendto() will get a value of -EINVAL, and it will > cause users to waste a lot of time checking parameters for errors. > > Return the real errno instead of -EINVAL. > > Signed-off-by: xu xin > Reviewed-by: Yang Yang > Cc: Si Hao > Cc: Dai Shixin > Cc: Jiang Xuexin > --- > net/ipv4/ip_output.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c > index 6ba1a0fafbaa..2d7cf083dff9 100644 > --- a/net/ipv4/ip_output.c > +++ b/net/ipv4/ip_output.c > @@ -201,6 +201,7 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s > unsigned int hh_len = LL_RESERVED_SPACE(dev); > struct neighbour *neigh; > bool is_v6gw = false; > + int res; > > if (rt->rt_type == RTN_MULTICAST) { > IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len); > @@ -214,8 +215,7 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s > } > > if (lwtunnel_xmit_redirect(dst->lwtstate)) { > - int res = lwtunnel_xmit(skb); > - > + res = lwtunnel_xmit(skb); > if (res < 0 || res == LWTUNNEL_XMIT_DONE) > return res; > } > @@ -223,8 +223,6 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s > rcu_read_lock(); > neigh = ip_neigh_for_gw(rt, skb, &is_v6gw); > if (!IS_ERR(neigh)) { > - int res; > - > sock_confirm_neigh(skb, neigh); > /* if crossing protocols, can not use the cached header */ > res = neigh_output(neigh, skb, is_v6gw); > @@ -236,7 +234,8 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s > net_dbg_ratelimited("%s: No header cache and no neighbour!\n", > __func__); > kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL); > - return -EINVAL; > + res = PTR_ERR(neigh); > + return res; I believe this part could be written as - return -EINVAL; + return PTR_ERR(neigh); and there is no need to change the code is other places. This will be easier to track/backport. > } > > static int ip_finish_output_gso(struct net *net, struct sock *sk,