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 0D238C433F5 for ; Thu, 19 May 2022 10:46:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234705AbiESKqM (ORCPT ); Thu, 19 May 2022 06:46:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48230 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236984AbiESKp7 (ORCPT ); Thu, 19 May 2022 06:45:59 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1C5FADE1 for ; Thu, 19 May 2022 03:45:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652957157; 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: in-reply-to:in-reply-to:references:references; bh=8rut9GNc4WtSroF96b47WlHm5eXtcsOWXAAJ8NlKUQQ=; b=EbXPD7GdFHOh1fW/kdjtxPSXrzpoLK1KMoxwIzRHLGUoMjqXmqskBM6Y8AoCwwDhFBBWrX E8tGSG8Z9f4HKeJNchXRlkp4n4mR7k01IFgZpVfPRyDt9C9EUxfvUOPqvJlfFyoLNWGqvN n07uMAQHrT6mW7/ChAGyqGSvB38dYlQ= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-619-MRRR5JCrPDmpB-zFt2lfjw-1; Thu, 19 May 2022 06:45:56 -0400 X-MC-Unique: MRRR5JCrPDmpB-zFt2lfjw-1 Received: by mail-ej1-f71.google.com with SMTP id gn26-20020a1709070d1a00b006f453043956so2323012ejc.15 for ; Thu, 19 May 2022 03:45:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=8rut9GNc4WtSroF96b47WlHm5eXtcsOWXAAJ8NlKUQQ=; b=DQD6qEpxQYubSFuRDSVALXJSl4C7EBejI0r1WRQlU/g8s+7OQ0gdYp4bxRcIISSbn4 tLQqxY3dLE8Tl7MOySxcjDI+p78F1d/xtwPNvCjey9jEl7hUelCKBYTRvYePsW7TKx7Z 300LpbedjHcTgGVdSvvY8uSIwiEXakDOcb0tIqe04bBC1FetPbzuBHVkRu5GaXIi2DDC 4JsaiEQ9rXyYNoCfRgrAboxqRe3g688Nn7bNweBlNNyExXrorvpjX3SbfNWuMh3oVwk5 W+NNP+vii05S+wyr8OTWhrX8CdGaChJb0AtPlt6eXISbAuy4zIy5jmriEnB/GppNP3Ko e5/Q== X-Gm-Message-State: AOAM531VbCdSHRrPqhsTtDvTn2H8/qIREC3xuRTkIlv72ruwTid0Zq4Y funuQfC9jkh3tn/UsAflh37q6WAVNyhmmq4aprWH7fV2GB8o0BpsyfIwZtaXs+UqcKyAOCKB+Qn OrOsM3zmzGBJg X-Received: by 2002:a17:907:961e:b0:6f4:b201:6629 with SMTP id gb30-20020a170907961e00b006f4b2016629mr3745628ejc.152.1652957153387; Thu, 19 May 2022 03:45:53 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx52dO1ml/cCp+uLuLPFVwIUuT7zd2gIPRWnBOP1j1BK0pQWadGJYAMHEh2QAWSCJvZgUTRrA== X-Received: by 2002:a17:907:961e:b0:6f4:b201:6629 with SMTP id gb30-20020a170907961e00b006f4b2016629mr3745561ejc.152.1652957152469; Thu, 19 May 2022 03:45:52 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([2a0c:4d80:42:443::2]) by smtp.gmail.com with ESMTPSA id j22-20020aa7ca56000000b0042acc78178bsm2623753edt.93.2022.05.19.03.45.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 May 2022 03:45:51 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 47CED38EE17; Thu, 19 May 2022 12:45:51 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Kumar Kartikeya Dwivedi , Alexei Starovoitov Cc: Lorenzo Bianconi , 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 In-Reply-To: <20220518224330.omsokbbhqoe5mc3v@apollo.legion> References: <40e7ce4b79c86c46e5fbf22e9cafb51b9172da19.1652870182.git.lorenzo@kernel.org> <87y1yy8t6j.fsf@toke.dk> <20220518224330.omsokbbhqoe5mc3v@apollo.legion> X-Clacks-Overhead: GNU Terry Pratchett Date: Thu, 19 May 2022 12:45:51 +0200 Message-ID: <87czg994ww.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Kumar Kartikeya Dwivedi writes: > 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. Sounds reasonable enough; I guess _insert would also need to sanity-check some of the values to prevent injecting invalid state into the conntrack table. > 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? Hmm, if they're different BTF IDs wouldn't the BPF program have to be aware of this and use two different structs for the pointer storage? That seems a bit awkward from an API PoV? Also, what about updating? For this to be useful with TCP, you'd really want to be able to update the CT state as the connection is going through the handshake state transitions... -Toke