From patchwork Wed May 27 22:30:39 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 477445 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 81E1614016A for ; Thu, 28 May 2015 08:31:10 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932410AbbE0Wa4 (ORCPT ); Wed, 27 May 2015 18:30:56 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:35626 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932127AbbE0Waw (ORCPT ); Wed, 27 May 2015 18:30:52 -0400 Received: by pdea3 with SMTP id a3so26677238pde.2 for ; Wed, 27 May 2015 15:30:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=AU7BmI1ot/tdV6hJdv7toGPw//two+ZLL2TTfvTDoeI=; b=kiiQlfDOlSmVFGddVOz7hYVnpS7tBnbJROuruJt0g666zoEmnGMjetSMvS1T8XifDA 5rLvQoVujk9jnzlxnKeAvMNT1Hv2WBfCcgTHbTfRqx8FLQcY8k5Qfc2y0fL9Wz+G3MGi iIbHOmzutHSPIR4SH5jHvOK9SSGqR2VgJKaRQr7mQ2FT1vJjJbFHYN+U/pYqOs86s8sy jJp+DToVuiVueFdmBV9+z6jAoA7Y4YVHZS0ageC3oriDGueKjomor+mI+6Rce9yLuy8y l1zn8Tw3HFHEfXweSe6qLEqwXPCvCqzfPfqScbeALDLK+ny1jEyucvIEMXeiXKn4UoZE nSSQ== X-Gm-Message-State: ALoCoQmQiJDISPnLcn9La/is7m6sCphRmW2jSD7YmXpu22j+kucsAHJJYowWSc2ckvuhTKx1lSCh X-Received: by 10.70.55.165 with SMTP id t5mr61676732pdp.102.1432765851363; Wed, 27 May 2015 15:30:51 -0700 (PDT) Received: from localhost.localdomain ([12.229.56.227]) by mx.google.com with ESMTPSA id fk4sm173586pbb.80.2015.05.27.15.30.50 (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 27 May 2015 15:30:50 -0700 (PDT) From: Alexei Starovoitov To: "David S. Miller" Cc: Daniel Borkmann , netdev@vger.kernel.org Subject: [PATCH net-next] bpf: allow BPF programs access skb->skb_iif and skb->dev->ifindex fields Date: Wed, 27 May 2015 15:30:39 -0700 Message-Id: <1432765839-7709-1-git-send-email-ast@plumgrid.com> X-Mailer: git-send-email 1.7.9.5 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org classic BPF already exposes skb->dev->ifindex via SKF_AD_IFINDEX extension. Allow eBPF program to access it as well. Note that classic aborts execution of the program if 'skb->dev == NULL' (which is inconvenient for program writers), whereas eBPF returns zero in such case. Also expose the 'skb_iif' field, since programs triggered by redirected packet need to known the original interface index. Summary: __skb->ifindex -> skb->dev->ifindex __skb->ingress_ifindex -> skb->skb_iif Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- include/uapi/linux/bpf.h | 2 ++ net/core/filter.c | 18 ++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f0a9af8b4dae..72f3080afa1e 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -236,6 +236,8 @@ struct __sk_buff { __u32 vlan_tci; __u32 vlan_proto; __u32 priority; + __u32 ingress_ifindex; + __u32 ifindex; }; #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/net/core/filter.c b/net/core/filter.c index 3adcca6f17a4..2c30d6632d66 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1499,6 +1499,24 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off, offsetof(struct sk_buff, priority)); break; + case offsetof(struct __sk_buff, ingress_ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, skb_iif) != 4); + + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, src_reg, + offsetof(struct sk_buff, skb_iif)); + break; + + case offsetof(struct __sk_buff, ifindex): + BUILD_BUG_ON(FIELD_SIZEOF(struct net_device, ifindex) != 4); + + *insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct sk_buff, dev)), + dst_reg, src_reg, + offsetof(struct sk_buff, dev)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, dst_reg, 0, 1); + *insn++ = BPF_LDX_MEM(BPF_W, dst_reg, dst_reg, + offsetof(struct net_device, ifindex)); + break; + case offsetof(struct __sk_buff, mark): return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn);