From patchwork Wed Mar 20 14:49:39 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Willem de Bruijn X-Patchwork-Id: 1059273 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="Hc5U9X+c"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44PXrt00yGz9sNf for ; Thu, 21 Mar 2019 01:50:05 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728252AbfCTOuD (ORCPT ); Wed, 20 Mar 2019 10:50:03 -0400 Received: from mail-qt1-f193.google.com ([209.85.160.193]:46714 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728222AbfCTOuC (ORCPT ); Wed, 20 Mar 2019 10:50:02 -0400 Received: by mail-qt1-f193.google.com with SMTP id z17so1763560qts.13 for ; Wed, 20 Mar 2019 07:50:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=8o4W8WkdmJpZl6Lc6s1+ki2S26z5uqWMe6DdbR52Oac=; b=Hc5U9X+ce9PYI7SIe0WLN6EWqZURyhKJgYIN80I+1cNDMujX78Xu8qoEE2vt4SgN91 TJFGxUNPUV/U0rnbpxWwUqeQzqQj2Ur1wNpMPmZB7CCfXkuAWRXhUDb+PCrOEtaPIZ90 +AS87YPzeqVe4HprWXisWgIVHeGWlq1TGT+kVTqDj2sm1pzSIKn6z5X/25iDRWInZmKO sNWTDXgQ4LqZ4+wA+F6RbXSYEKuo9UoLfFt2urHon1F2hNBr/T466WAhA5uHGQw1m/jx XkNUSSeRvaUqWWLhAZRvjSVuiWqWjDFoG0aYAeD/7yXP+9z2XyPaJQNbVMIpo2rP79hc K3Ww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=8o4W8WkdmJpZl6Lc6s1+ki2S26z5uqWMe6DdbR52Oac=; b=TcfjwlQivf8khzKCjUML3218cpg9Vhde35GzNqyExhn9CKAOeCHYZAcqI7Dgl3Vcor xjVVbac5/yxGN7fS77+Zl1l86QDnD9ZbI96nXRKmrA1lq1+m1+obuFSyfoOcYC+5c2Rv nPO+LYUkoyCGmT3MLzTYnL+hhxMMP+EwRJ6sKtQ1MzRvcsq6NLrm660HE/tS4u5wIwi0 JuiRKG01Qqv08f1Cs/Ns2mygyOW5QECC0VDaJMEHgh8PmfNV4RQXaCarevjmrCCg6M7T RDK+vsTzIJyTkslK/jn04jsUisIXZwB3vrMjBQvmeuSWDEN84/z12OiPeeeKQJGr29F2 Iw0g== X-Gm-Message-State: APjAAAUiYXGKI7vArDSLkFx17wSaOrns8+JnXTKMyc4H++BTVYVvWkep QTrwghrs2OPbcwfCjffCYZIidzuN X-Google-Smtp-Source: APXvYqyVdW3zlMiRC3i189ljmkZxa+Y4kxHhP6Tspn+Mu3xsluFNY7Ly65+ue0DAz9ywlpWLUEZ83g== X-Received: by 2002:a0c:ad4a:: with SMTP id v10mr6810764qvc.232.1553093400257; Wed, 20 Mar 2019 07:50:00 -0700 (PDT) Received: from willemb1.nyc.corp.google.com ([2620:0:1003:315:3fa1:a34c:1128:1d39]) by smtp.gmail.com with ESMTPSA id x201sm1142257qkb.92.2019.03.20.07.49.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Mar 2019 07:49:59 -0700 (PDT) From: Willem de Bruijn To: netdev@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, sdf@google.com, posk@google.com, Willem de Bruijn Subject: [PATCH bpf-next 08/13] bpf: add bpf_skb_adjust_room flag BPF_F_ADJ_ROOM_FIXED_GSO Date: Wed, 20 Mar 2019 10:49:39 -0400 Message-Id: <20190320144944.147862-9-willemdebruijn.kernel@gmail.com> X-Mailer: git-send-email 2.21.0.225.g810b269d1ac-goog In-Reply-To: <20190320144944.147862-1-willemdebruijn.kernel@gmail.com> References: <20190320144944.147862-1-willemdebruijn.kernel@gmail.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Willem de Bruijn bpf_skb_adjust_room adjusts gso_size of gso packets to account for the pushed or popped header room. This is not allowed with UDP, where gso_size delineates datagrams. Add an option to avoid these updates and allow this call for datagrams. It can also be used with TCP, when MSS is known to allow headroom, e.g., through MSS clamping or route MTU. Link: https://patchwork.ozlabs.org/patch/1052497/ Signed-off-by: Willem de Bruijn Reviewed-by: Alan Maguire --- include/uapi/linux/bpf.h | 4 ++++ net/core/filter.c | 36 +++++++++++++++++++++++++----------- 2 files changed, 29 insertions(+), 11 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4f5c918e6fcf4..0eda8f564a381 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2593,6 +2593,10 @@ enum bpf_func_id { /* Current network namespace */ #define BPF_F_CURRENT_NETNS (-1L) +/* BPF_FUNC_skb_adjust_room flags. */ +#define BPF_F_ADJ_ROOM_FIXED_GSO (1ULL << 0) +#define BPF_F_ADJ_ROOM_MASK (BPF_F_ADJ_ROOM_FIXED_GSO) + /* Mode for BPF_FUNC_skb_adjust_room helper. */ enum bpf_adj_room_mode { BPF_ADJ_ROOM_NET, diff --git a/net/core/filter.c b/net/core/filter.c index 1a0cf578b4502..e346e48098000 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2963,12 +2963,17 @@ static u32 bpf_skb_net_base_len(const struct sk_buff *skb) } } -static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff) +static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff, + u64 flags) { int ret; - if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) - return -ENOTSUPP; + if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) { + /* udp gso_size delineates datagrams, only allow if fixed */ + if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) || + !(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) + return -ENOTSUPP; + } ret = skb_cow_head(skb, len_diff); if (unlikely(ret < 0)) @@ -2982,7 +2987,9 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff) struct skb_shared_info *shinfo = skb_shinfo(skb); /* Due to header grow, MSS needs to be downgraded. */ - skb_decrease_gso_size(shinfo, len_diff); + if (!(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) + skb_decrease_gso_size(shinfo, len_diff); + /* Header must be checked, and gso_segs recomputed. */ shinfo->gso_type |= SKB_GSO_DODGY; shinfo->gso_segs = 0; @@ -2991,12 +2998,17 @@ static int bpf_skb_net_grow(struct sk_buff *skb, u32 off, u32 len_diff) return 0; } -static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff) +static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff, + u64 flags) { int ret; - if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) - return -ENOTSUPP; + if (skb_is_gso(skb) && !skb_is_gso_tcp(skb)) { + /* udp gso_size delineates datagrams, only allow if fixed */ + if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) || + !(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) + return -ENOTSUPP; + } ret = skb_unclone(skb, GFP_ATOMIC); if (unlikely(ret < 0)) @@ -3010,7 +3022,9 @@ static int bpf_skb_net_shrink(struct sk_buff *skb, u32 off, u32 len_diff) struct skb_shared_info *shinfo = skb_shinfo(skb); /* Due to header shrink, MSS can be upgraded. */ - skb_increase_gso_size(shinfo, len_diff); + if (!(flags & BPF_F_ADJ_ROOM_FIXED_GSO)) + skb_increase_gso_size(shinfo, len_diff); + /* Header must be checked, and gso_segs recomputed. */ shinfo->gso_type |= SKB_GSO_DODGY; shinfo->gso_segs = 0; @@ -3037,7 +3051,7 @@ BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff, u32 off; int ret; - if (unlikely(flags)) + if (unlikely(flags & ~BPF_F_ADJ_ROOM_MASK)) return -EINVAL; if (unlikely(len_diff_abs > 0xfffU)) return -EFAULT; @@ -3065,8 +3079,8 @@ BPF_CALL_4(bpf_skb_adjust_room, struct sk_buff *, skb, s32, len_diff, !skb_is_gso(skb)))) return -ENOTSUPP; - ret = shrink ? bpf_skb_net_shrink(skb, off, len_diff_abs) : - bpf_skb_net_grow(skb, off, len_diff_abs); + ret = shrink ? bpf_skb_net_shrink(skb, off, len_diff_abs, flags) : + bpf_skb_net_grow(skb, off, len_diff_abs, flags); bpf_compute_data_pointers(skb); return ret;