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=-8.3 required=3.0 tests=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 46FC0C47247 for ; Sat, 9 May 2020 16:09:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 260232192A for ; Sat, 9 May 2020 16:09:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728237AbgEIQJJ (ORCPT ); Sat, 9 May 2020 12:09:09 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:44441 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727863AbgEIQJJ (ORCPT ); Sat, 9 May 2020 12:09:09 -0400 Received: from dimstar.local.net (n175-34-64-112.sun1.vic.optusnet.com.au [175.34.64.112]) by mail105.syd.optusnet.com.au (Postfix) with SMTP id 09D223A3FF2 for ; Sun, 10 May 2020 02:09:05 +1000 (AEST) Received: (qmail 30888 invoked by uid 501); 9 May 2020 16:09:03 -0000 Date: Sun, 10 May 2020 02:09:03 +1000 From: Duncan Roe To: netfilter-devel@vger.kernel.org Subject: Re: [PATCH libnetfilter_queue 2/2] pktbuff: add pktb_head_alloc(), pktb_setup() and pktb_head_size() Message-ID: <20200509160903.GF26529@dimstar.local.net> Mail-Followup-To: netfilter-devel@vger.kernel.org References: <20200509091141.10619-1-pablo@netfilter.org> <20200509091141.10619-2-pablo@netfilter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200509091141.10619-2-pablo@netfilter.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=QIgWuTDL c=1 sm=1 tr=0 a=keeXcwCgVCrAuxOn72dlvA==:117 a=keeXcwCgVCrAuxOn72dlvA==:17 a=kj9zAlcOel0A:10 a=sTwFKg_x9MkA:10 a=RSmzAf-M6YYA:10 a=3HDBlxybAAAA:8 a=37rGoeeWIGCFrgcYRlgA:9 a=CjuIK1q_8ugA:10 a=laEoCiVfU_Unz3mSdgXN:22 Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Sat, May 09, 2020 at 11:11:41AM +0200, Pablo Neira Ayuso wrote: > Add two new helper functions, as alternative to pktb_alloc(). > > * pktb_setup() allows you to skip memcpy()'ing the payload from the > netlink message. > > * pktb_head_size() returns the size of the pkt_buff opaque object. > > * pktb_head_alloc() allows you to allocate the pkt_buff in the heap. > > Signed-off-by: Pablo Neira Ayuso > --- > include/libnetfilter_queue/pktbuff.h | 7 +++++++ > src/extra/pktbuff.c | 20 ++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > diff --git a/include/libnetfilter_queue/pktbuff.h b/include/libnetfilter_queue/pktbuff.h > index 42bc153ec337..a27582b02840 100644 > --- a/include/libnetfilter_queue/pktbuff.h > +++ b/include/libnetfilter_queue/pktbuff.h > @@ -6,6 +6,13 @@ struct pkt_buff; > struct pkt_buff *pktb_alloc(int family, void *data, size_t len, size_t extra); > void pktb_free(struct pkt_buff *pktb); > > +#define NFQ_BUFFER_SIZE (0xffff + (MNL_SOCKET_BUFFER_SIZE / 2) > +struct pkt_buff *pktb_setup(struct pkt_buff *pktb, int family, uint8_t *data, > + size_t len, size_t extra); > +size_t pktb_head_size(void); > + > +#define pktb_head_alloc() (struct pkt_buff *)(malloc(pktb_head_size())) > + > uint8_t *pktb_data(struct pkt_buff *pktb); > uint32_t pktb_len(struct pkt_buff *pktb); > > diff --git a/src/extra/pktbuff.c b/src/extra/pktbuff.c > index 118ad898f63b..6acefbe72a9b 100644 > --- a/src/extra/pktbuff.c > +++ b/src/extra/pktbuff.c > @@ -103,6 +103,26 @@ struct pkt_buff *pktb_alloc(int family, void *data, size_t len, size_t extra) > return pktb; > } > > +EXPORT_SYMBOL > +struct pkt_buff *pktb_setup(struct pkt_buff *pktb, int family, uint8_t *buf, > + size_t len, size_t extra) > +{ > + pktb->data_len = len + extra; Are you proposing to be able to use extra space in the receive buffer? I think that is unsafe. mnl_cb_run() steps through that bufffer and needs a zero following the last message to know there are no more. At least, that's how it looks to me on stepping through with gdb. > + pktb->data = buf; > + pktb->len = len; > + > + if (__pktb_setup(family, pktb) < 0) > + return NULL; > + > + return pktb; > +} > + > +EXPORT_SYMBOL > +size_t pktb_head_size(void) > +{ > + return sizeof(struct pkt_buff); > +} > + > /** > * pktb_data - get pointer to network packet > * \param pktb Pointer to userspace packet buffer > -- > 2.20.1 > Will post an alternative in the morning - D.