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 E3440C433FE for ; Wed, 18 May 2022 22:42:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229894AbiERWmq (ORCPT ); Wed, 18 May 2022 18:42:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229656AbiERWmo (ORCPT ); Wed, 18 May 2022 18:42:44 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F61B14D782; Wed, 18 May 2022 15:42:43 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id l14so3464624pjk.2; Wed, 18 May 2022 15:42:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=o/5HbRUzUeishq4OoRNF2vTxxeTguE/szejcn40/RQ8=; b=XL6GlW8tbi15ldh/hhco82zJ+xLlWJgXXEKw36mepVErwbWRXrPknk4m4+QR03LSQF OcvYbg90vkXwmL0VMKX9siCStdsl0e55o/N1Nye5JaeGwPPiUGGxJzcRQYisRWAfgfe7 OP7JBxmRa+Qx3XfaNe1Ndv8JAYqqg2RYcYXegTYuGIM4yI8nR1DY+aRQKYD4LJ8mUoKu kzSJvQaOR0Q0IzpJ9byM7LnKXtALM31Jr9+jDNTzq3ByT6SPzSxOPn3i7kxU+6vZbCeq +C5i7ojt+z0/45D7BVISXEJ0hx5D67qwIpuinbOairOBDM86tHouDVHlcDRgzICalbaZ jyfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=o/5HbRUzUeishq4OoRNF2vTxxeTguE/szejcn40/RQ8=; b=Zgtt5pdeLwC7MfF0nplNiwR5cCCoGaPR1QaTiQlppfJUdzEbH8RBDMd1EA1IjpAvqj hRmwyvhRswAFkYmm7ZUa6SYP/GM5fSG3MdVUmnZz7uvTR0Pe/wKqbDiWdPzhmhYCrxdh NcHl80T7st7rvg1HSfAoxmX0Yn4pWxC2DOQ9Y057qIpR+HV+yMN4VHG+CWWkcp2Zoxkd cDxii4rZSJRbyHXf6bVzpnLVaMsS6I7jfJhCDCAnSWNfJxrJxhbyxnFMdoIy9HUetSsQ 9fJwZTubw4GhBwSfcBgBqczlNIXEtndbXxYwFuNIL7NBlNG3O9gnHbjs+e7Dw6tGOqaJ OhTw== X-Gm-Message-State: AOAM530uuLJg5965r1NZCQPpTDfi3k2KOh2XWioEhkDpyTuu4tB1WJmY WciVnJxw5NZhfFy5prPX1cU= X-Google-Smtp-Source: ABdhPJxqrql2Mi72Vgj+Hv9WaAqmjbILCqjPcNYNfKcmZqvZIxkPzhuq/7QbRMUBgSqtHkrhFoa5qQ== X-Received: by 2002:a17:90b:4d90:b0:1dc:c03e:3a39 with SMTP id oj16-20020a17090b4d9000b001dcc03e3a39mr2317650pjb.116.1652913762949; Wed, 18 May 2022 15:42:42 -0700 (PDT) Received: from localhost ([157.51.69.231]) by smtp.gmail.com with ESMTPSA id k11-20020aa788cb000000b0050dc76281c7sm2486111pff.161.2022.05.18.15.42.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 May 2022 15:42:42 -0700 (PDT) Date: Thu, 19 May 2022 04:13:30 +0530 From: Kumar Kartikeya Dwivedi To: Alexei Starovoitov Cc: Lorenzo Bianconi , Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= , Lorenzo Bianconi , bpf , Network Development , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , "David S. Miller" , Jakub Kicinski , Eric Dumazet , Paolo Abeni , Pablo Neira Ayuso , Florian Westphal , netfilter-devel , Jesper Dangaard Brouer Subject: Re: [PATCH v3 bpf-next 4/5] net: netfilter: add kfunc helper to add a new ct entry Message-ID: <20220518224330.omsokbbhqoe5mc3v@apollo.legion> References: <40e7ce4b79c86c46e5fbf22e9cafb51b9172da19.1652870182.git.lorenzo@kernel.org> <87y1yy8t6j.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, May 19, 2022 at 03:44:58AM IST, Alexei Starovoitov wrote: > On Wed, May 18, 2022 at 2:09 PM Lorenzo Bianconi > wrote: > > > > > Lorenzo Bianconi writes: > > > > > > > Introduce bpf_xdp_ct_add and bpf_skb_ct_add kfunc helpers in order to > > > > add a new entry to ct map from an ebpf program. > > > > Introduce bpf_nf_ct_tuple_parse utility routine. > > > > > > > > Signed-off-by: Lorenzo Bianconi > > > > --- > > > > net/netfilter/nf_conntrack_bpf.c | 212 +++++++++++++++++++++++++++---- > > > > 1 file changed, 189 insertions(+), 23 deletions(-) > > > > > > > > diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c > > > > index a9271418db88..3d31b602fdf1 100644 > > > > --- a/net/netfilter/nf_conntrack_bpf.c > > > > +++ b/net/netfilter/nf_conntrack_bpf.c > > > > @@ -55,41 +55,114 @@ enum { > > > > NF_BPF_CT_OPTS_SZ = 12, > > > > }; > > > > > > > > -static struct nf_conn *__bpf_nf_ct_lookup(struct net *net, > > > > - struct bpf_sock_tuple *bpf_tuple, > > > > - u32 tuple_len, u8 protonum, > > > > - s32 netns_id, u8 *dir) > > > > +static int bpf_nf_ct_tuple_parse(struct bpf_sock_tuple *bpf_tuple, > > > > + u32 tuple_len, u8 protonum, u8 dir, > > > > + struct nf_conntrack_tuple *tuple) > > > > { > > > > - struct nf_conntrack_tuple_hash *hash; > > > > - struct nf_conntrack_tuple tuple; > > > > - struct nf_conn *ct; > > > > + union nf_inet_addr *src = dir ? &tuple->dst.u3 : &tuple->src.u3; > > > > + union nf_inet_addr *dst = dir ? &tuple->src.u3 : &tuple->dst.u3; > > > > + union nf_conntrack_man_proto *sport = dir ? (void *)&tuple->dst.u > > > > + : &tuple->src.u; > > > > + union nf_conntrack_man_proto *dport = dir ? &tuple->src.u > > > > + : (void *)&tuple->dst.u; > > > > > > > > if (unlikely(protonum != IPPROTO_TCP && protonum != IPPROTO_UDP)) > > > > - return ERR_PTR(-EPROTO); > > > > - if (unlikely(netns_id < BPF_F_CURRENT_NETNS)) > > > > - return ERR_PTR(-EINVAL); > > > > + return -EPROTO; > > > > + > > > > + memset(tuple, 0, sizeof(*tuple)); > > > > > > > > - memset(&tuple, 0, sizeof(tuple)); > > > > switch (tuple_len) { > > > > case sizeof(bpf_tuple->ipv4): > > > > - tuple.src.l3num = AF_INET; > > > > - tuple.src.u3.ip = bpf_tuple->ipv4.saddr; > > > > - tuple.src.u.tcp.port = bpf_tuple->ipv4.sport; > > > > - tuple.dst.u3.ip = bpf_tuple->ipv4.daddr; > > > > - tuple.dst.u.tcp.port = bpf_tuple->ipv4.dport; > > > > + tuple->src.l3num = AF_INET; > > > > + src->ip = bpf_tuple->ipv4.saddr; > > > > + sport->tcp.port = bpf_tuple->ipv4.sport; > > > > + dst->ip = bpf_tuple->ipv4.daddr; > > > > + dport->tcp.port = bpf_tuple->ipv4.dport; > > > > break; > > > > case sizeof(bpf_tuple->ipv6): > > > > - tuple.src.l3num = AF_INET6; > > > > - memcpy(tuple.src.u3.ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr)); > > > > - tuple.src.u.tcp.port = bpf_tuple->ipv6.sport; > > > > - memcpy(tuple.dst.u3.ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr)); > > > > - tuple.dst.u.tcp.port = bpf_tuple->ipv6.dport; > > > > + tuple->src.l3num = AF_INET6; > > > > + memcpy(src->ip6, bpf_tuple->ipv6.saddr, sizeof(bpf_tuple->ipv6.saddr)); > > > > + sport->tcp.port = bpf_tuple->ipv6.sport; > > > > + memcpy(dst->ip6, bpf_tuple->ipv6.daddr, sizeof(bpf_tuple->ipv6.daddr)); > > > > + dport->tcp.port = bpf_tuple->ipv6.dport; > > > > break; > > > > default: > > > > - return ERR_PTR(-EAFNOSUPPORT); > > > > + return -EAFNOSUPPORT; > > > > } > > > > + tuple->dst.protonum = protonum; > > > > + tuple->dst.dir = dir; > > > > + > > > > + return 0; > > > > +} > > > > > > > > - tuple.dst.protonum = protonum; > > > > +struct nf_conn * > > > > +__bpf_nf_ct_alloc_entry(struct net *net, struct bpf_sock_tuple *bpf_tuple, > > > > + u32 tuple_len, u8 protonum, s32 netns_id, u32 timeout) > > > > +{ > > > > + struct nf_conntrack_tuple otuple, rtuple; > > > > + struct nf_conn *ct; > > > > + int err; > > > > + > > > > + if (unlikely(netns_id < BPF_F_CURRENT_NETNS)) > > > > + return ERR_PTR(-EINVAL); > > > > + > > > > + err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, protonum, > > > > + IP_CT_DIR_ORIGINAL, &otuple); > > > > + if (err < 0) > > > > + return ERR_PTR(err); > > > > + > > > > + err = bpf_nf_ct_tuple_parse(bpf_tuple, tuple_len, protonum, > > > > + IP_CT_DIR_REPLY, &rtuple); > > > > + if (err < 0) > > > > + return ERR_PTR(err); > > > > + > > > > + if (netns_id >= 0) { > > > > + net = get_net_ns_by_id(net, netns_id); > > > > + if (unlikely(!net)) > > > > + return ERR_PTR(-ENONET); > > > > + } > > > > + > > > > + ct = nf_conntrack_alloc(net, &nf_ct_zone_dflt, &otuple, &rtuple, > > > > + GFP_ATOMIC); > > > > + if (IS_ERR(ct)) > > > > + goto out; > > > > + > > > > + ct->timeout = timeout * HZ + jiffies; > > > > + ct->status |= IPS_CONFIRMED; > > > > + > > > > + memset(&ct->proto, 0, sizeof(ct->proto)); > > > > + if (protonum == IPPROTO_TCP) > > > > + ct->proto.tcp.state = TCP_CONNTRACK_ESTABLISHED; > > > > > > Hmm, isn't it a bit limiting to hard-code this to ESTABLISHED > > > connections? Presumably for TCP you'd want to use this when you see a > > > SYN and then rely on conntrack to help with the subsequent state > > > tracking for when the SYN-ACK comes back? What's the usecase for > > > creating an entry in ESTABLISHED state, exactly? > > > > I guess we can even add a parameter and pass the state from the caller. > > I was not sure if it is mandatory. > > It's probably cleaner and more flexible to split > _alloc and _insert into two kfuncs and let bpf > prog populate ct directly. Right, so we can just whitelist a few fields and allow assignments into those. One small problem is that we should probably only permit this for nf_conn PTR_TO_BTF_ID obtained from _alloc, and make it rdonly on _insert. We can do the rw->ro conversion by taking in ref from alloc, and releasing on _insert, then returning ref from _insert. For the other part, either return a different shadow PTR_TO_BTF_ID with only the fields that can be set, convert insns for it, and then on insert return the rdonly PTR_TO_BTF_ID of struct nf_conn, or otherwise store the source func in the per-register state and use that to deny BPF_WRITE for normal nf_conn. Thoughts? -- Kartikeya