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 X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A135C2BB1D for ; Tue, 14 Apr 2020 22:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4082A2064A for ; Tue, 14 Apr 2020 22:28:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ojS1F+HM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391974AbgDNW17 (ORCPT ); Tue, 14 Apr 2020 18:27:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2391947AbgDNW1x (ORCPT ); Tue, 14 Apr 2020 18:27:53 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20B21C061A0C for ; Tue, 14 Apr 2020 15:27:53 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id f13so16458253wrm.13 for ; Tue, 14 Apr 2020 15:27:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ZgJpVzWjv2/ZrpsimyFCOTAickfRqJg/npiQg/ZTJ2k=; b=ojS1F+HMQ6TCIHlTctOSiMHfi+ohonQe9nOaQbWm/rD1652unosSkGjfKc++c8UU2W spyZ4uk2AXMG8WCiWxhn9vobdKdLOnAwQJEJYzQow6p5Ie9hFWIlgtmB+ypx5VN7U/k1 Ci9lQwvv7f/U6dMp6Uspl25U4y+Mvn3HTloh9unZf2IpFwR4V5unzJ/FWrs5aYayFlcP GnqBZAxcboF3tq3m+8tDZXQluTAhstACOM9aBWd8wsqrOxEJQg8xnc121JPFxolo48Mb qFSZ+uxNlaZwuctzHLfWXc0kFxJO4LvyKK9TNfp08BOOa+klcl0/xfJUY2PFjhTWAFQF khhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ZgJpVzWjv2/ZrpsimyFCOTAickfRqJg/npiQg/ZTJ2k=; b=hfPb1cZOJ0HBwDtfeltY7Ia9Rhhk4s6XoSpmZIzaOpbjJRwKOOcuspFmWxa3FsgBzT KPvvT2UYzpo5OiULO8X7h27dhrIW2agugAxfejEHQey8EBlpgj2ItdW4PJVOU31cIcZZ P2sZIN4ker6Dq2U/9+be6xoV+d9LqFrSOuhhDPF5D9eqYOoK2wcZpIjNLhE6YIf1IpdT p7BYeoHSfja9w9UkWOfbh64QpnaidAU2NLhkB0/3D+XBlBfXUV0JYWK+HS+DxmI85rBV u+Qi1LzhJPLcmt+9vCxA41vc44S6Y1Sy2+Qtu0GGqH9Un6O7h+2tkmp5kD21SyXf0t5H YkWg== X-Gm-Message-State: AGi0PuYGI2GU37/nTAdQgCBl6tADww0XkM3VwPpejCzpEF5xlBJFZUkl 9KGubMQ78JrSorS4/4c5Egw= X-Google-Smtp-Source: APiQypL1YxACDI8A2eHe2FVGP2V4pl0/+T+HH0aXwa+RrgN9rWvtfqGXdKMZAZ821/kOZ433SyVP0g== X-Received: by 2002:adf:a345:: with SMTP id d5mr22579668wrb.23.1586903271726; Tue, 14 Apr 2020 15:27:51 -0700 (PDT) Received: from white ([2a02:2f01:8515:ef00:146c:7647:7e6f:9c9b]) by smtp.gmail.com with ESMTPSA id w17sm12363935wru.20.2020.04.14.15.27.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2020 15:27:51 -0700 (PDT) Date: Wed, 15 Apr 2020 01:27:49 +0300 From: =?utf-8?B?TGXFn2UgRG9ydSBDxINsaW4=?= To: Eric Dumazet , netdev@vger.kernel.org Cc: David Miller , Alexey Kuznetsov , Hideaki YOSHIFUJI , Leon Romanovsky Subject: Re: [PATCH v3] net: UDP repair mode for retrieving the send queue of corked UDP socket Message-ID: <20200414222749.GA22558@white> References: <20200414090925.GA10402@white> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Apr 14, 2020 at 11:43:59AM -0700, Eric Dumazet wrote: > > > On 4/14/20 2:09 AM, Lese Doru Calin wrote: > > In this year's edition of GSoC, there is a project idea for CRIU to add > > support for checkpoint/restore of cork-ed UDP sockets. But to add it, the > > kernel API needs to be extended. > > > > This is what this patch does. It adds UDP "repair mode" for UDP sockets in > > a similar approach to the TCP "repair mode", but only the send queue is > > necessary to be retrieved. So the patch extends the recv and setsockopt > > syscalls. Using UDP_REPAIR option in setsockopt, caller can set the socket > > in repair mode. If it is setted, the recv/recvfrom/recvmsg will receive the > > write queue and the destination of the data. As in the TCP mode, to change > > the repair mode requires the CAP_NET_ADMIN capability and to receive data > > the caller is obliged to use the MSG_PEEK flag. > > > > Signed-off-by: Lese Doru Calin > > --- > > include/linux/udp.h | 3 ++- > > include/uapi/linux/udp.h | 1 + > > net/ipv4/udp.c | 55 ++++++++++++++++++++++++++++++++++++++++ > > net/ipv6/udp.c | 45 ++++++++++++++++++++++++++++++++ > > 4 files changed, 103 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/udp.h b/include/linux/udp.h > > index aa84597bdc33..b22bd70118ce 100644 > > --- a/include/linux/udp.h > > +++ b/include/linux/udp.h > > @@ -51,7 +51,8 @@ struct udp_sock { > > * different encapsulation layer set > > * this > > */ > > - gro_enabled:1; /* Can accept GRO packets */ > > + gro_enabled:1, /* Can accept GRO packets */ > > + repair:1;/* Receive the send queue */ > > /* > > * Following member retains the information to create a UDP header > > * when the socket is uncorked. > > diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h > > index 4828794efcf8..2fe78329d6da 100644 > > --- a/include/uapi/linux/udp.h > > +++ b/include/uapi/linux/udp.h > > @@ -29,6 +29,7 @@ struct udphdr { > > > > /* UDP socket options */ > > #define UDP_CORK 1 /* Never send partially complete segments */ > > +#define UDP_REPAIR 19 /* Receive the send queue */ > > #define UDP_ENCAP 100 /* Set the socket to accept encapsulated packets */ > > #define UDP_NO_CHECK6_TX 101 /* Disable sending checksum for UDP6X */ > > #define UDP_NO_CHECK6_RX 102 /* Disable accpeting checksum for UDP6 */ > > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > > index 32564b350823..dc9d15d564d6 100644 > > --- a/net/ipv4/udp.c > > +++ b/net/ipv4/udp.c > > @@ -1720,6 +1720,28 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, > > } > > EXPORT_SYMBOL(__skb_recv_udp); > > > > +static int udp_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > > +{ > > + int copy, copied = 0, err = 0; > > + struct sk_buff *skb; > > + > > + skb_queue_walk(&sk->sk_write_queue, skb) { > > + copy = len - copied; > > + if (copy > skb->len - off) > > + copy = skb->len - off; > > + > > + err = skb_copy_datagram_msg(skb, off, msg, copy); > > + if (err) > > + break; > > + > > + copied += copy; > > + > > + if (len <= copied) > > + break; > > + } > > + return err ?: copied; > > +} > > + > > /* > > * This should be easy, if there is something there we > > * return it, otherwise we block. > > @@ -1729,8 +1751,10 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > int flags, int *addr_len) > > { > > struct inet_sock *inet = inet_sk(sk); > > + struct udp_sock *up = udp_sk(sk); > > DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name); > > struct sk_buff *skb; > > + struct flowi4 *fl4; > > unsigned int ulen, copied; > > int off, err, peeking = flags & MSG_PEEK; > > int is_udplite = IS_UDPLITE(sk); > > @@ -1739,6 +1763,12 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > if (flags & MSG_ERRQUEUE) > > return ip_recv_error(sk, msg, len, addr_len); > > > > + if (unlikely(up->repair)) { > > Socket lock is not held, disaster seems possible :/ > I missed that. Sorry. > > + if (!peeking) > > + return -EPERM; > > + goto recv_sndq; > > + } > > + > > > Really, I would rather stop adding code in fast path for REPAIR stuff. > > A new setsockopt() would be much better I think. > I could implement it as a option for getsockopt syscall, with a pointer to a buffer or a user_msghdr as a parameter, so that other syscalls are not affected. > > try_again: > > off = sk_peek_offset(sk, flags); > > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > > @@ -1832,6 +1862,18 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock, > > cond_resched(); > > msg->msg_flags &= ~MSG_TRUNC; > > goto try_again; > > + > > +recv_sndq: > > + off = sizeof(struct iphdr) + sizeof(struct udphdr); > > + if (sin) { > > + fl4 = &inet->cork.fl.u.ip4; > > + sin->sin_family = AF_INET; > > + sin->sin_port = fl4->fl4_dport; > > + sin->sin_addr.s_addr = fl4->daddr; > > + memset(sin->sin_zero, 0, sizeof(sin->sin_zero)); > > + *addr_len = sizeof(*sin); > > + } > > + return udp_peek_sndq(sk, msg, off, len); > > } > > > > int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) > > @@ -2557,6 +2599,15 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, > > } > > break; > > > > + case UDP_REPAIR: > > + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) > > + err = -EPERM; > > + else if (val != 0) > > + up->repair = 1; > > + else > > + up->repair = 0; > > + break; > > + > > case UDP_ENCAP: > > switch (val) { > > case 0: > > @@ -2678,6 +2729,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname, > > val = up->corkflag; > > break; > > > > + case UDP_REPAIR: > > + val = up->repair; > > + break; > > + > > case UDP_ENCAP: > > val = up->encap_type; > > break; > > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c > > index 7d4151747340..ec653f9fce2d 100644 > > --- a/net/ipv6/udp.c > > +++ b/net/ipv6/udp.c > > @@ -250,6 +250,28 @@ struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be > > EXPORT_SYMBOL_GPL(udp6_lib_lookup); > > #endif > > > > +static int udp6_peek_sndq(struct sock *sk, struct msghdr *msg, int off, int len) > > +{ > > + int copy, copied = 0, err = 0; > > + struct sk_buff *skb; > > + > > + skb_queue_walk(&sk->sk_write_queue, skb) { > > + copy = len - copied; > > + if (copy > skb->len - off) > > + copy = skb->len - off; > > + > > + err = skb_copy_datagram_msg(skb, off, msg, copy); > > + if (err) > > + break; > > + > > + copied += copy; > > + > > + if (len <= copied) > > + break; > > + } > > + return err ?: copied; > > +} > > + > > /* do not use the scratch area len for jumbogram: their length execeeds the > > * scratch area space; note that the IP6CB flags is still in the first > > * cacheline, so checking for jumbograms is cheap > > @@ -269,7 +291,9 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > { > > struct ipv6_pinfo *np = inet6_sk(sk); > > struct inet_sock *inet = inet_sk(sk); > > + struct udp_sock *up = udp_sk(sk); > > struct sk_buff *skb; > > + struct flowi6 *fl6; > > unsigned int ulen, copied; > > int off, err, peeking = flags & MSG_PEEK; > > int is_udplite = IS_UDPLITE(sk); > > @@ -283,6 +307,12 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > if (np->rxpmtu && np->rxopt.bits.rxpmtu) > > return ipv6_recv_rxpmtu(sk, msg, len, addr_len); > > > > + if (unlikely(up->repair)) { > > + if (!peeking) > > + return -EPERM; > > + goto recv_sndq; > > + } > > + > > try_again: > > off = sk_peek_offset(sk, flags); > > skb = __skb_recv_udp(sk, flags, noblock, &off, &err); > > @@ -394,6 +424,21 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, > > cond_resched(); > > msg->msg_flags &= ~MSG_TRUNC; > > goto try_again; > > + > > +recv_sndq: > > + off = sizeof(struct ipv6hdr) + sizeof(struct udphdr); > > + if (msg->msg_name) { > > + DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name); > > + > > + fl6 = &inet->cork.fl.u.ip6; > > + sin6->sin6_family = AF_INET6; > > + sin6->sin6_port = fl6->fl6_dport; > > + sin6->sin6_flowinfo = 0; > > + sin6->sin6_addr = fl6->daddr; > > + sin6->sin6_scope_id = fl6->flowi6_oif; > > + *addr_len = sizeof(*sin6); > > + } > > + return udp6_peek_sndq(sk, msg, off, len); > > } > > > > DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key); > >