Return-Path: Date: Mon, 1 Dec 2014 15:34:45 +0100 From: Alexander Aring To: linux-bluetooth@vger.kernel.org Cc: linux-wpan@vger.kernel.org, kernel@pengutronix.de, Jukka Rissanen , Martin Townsend Subject: Re: [PATCHv2 bluetooth-next 1/2] 6lowpan: add generic nhc layer interface Message-ID: <20141201143441.GA996@omega> References: <1417295683-22682-1-git-send-email-alex.aring@gmail.com> <1417295683-22682-2-git-send-email-alex.aring@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <1417295683-22682-2-git-send-email-alex.aring@gmail.com> Sender: linux-bluetooth-owner@vger.kernel.org List-ID: On Sat, Nov 29, 2014 at 10:14:42PM +0100, Alexander Aring wrote: > This patch adds a generic next header compression layer interface. There > exists various methods to do a header compression after 6LoWPAN header > to save payload. This introduce a generic nhc header which allow a > simple adding of a new header compression format instead of a static > implementation inside the 6LoWPAN header compression and uncompression > function. > > Signed-off-by: Alexander Aring > Cc: Jukka Rissanen > Cc: Martin Townsend > --- > net/6lowpan/Makefile | 2 +- > net/6lowpan/nhc.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++++++ > net/6lowpan/nhc.h | 130 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 306 insertions(+), 1 deletion(-) > create mode 100644 net/6lowpan/nhc.c > create mode 100644 net/6lowpan/nhc.h > > diff --git a/net/6lowpan/Makefile b/net/6lowpan/Makefile > index 415886b..4215602 100644 > --- a/net/6lowpan/Makefile > +++ b/net/6lowpan/Makefile > @@ -1,3 +1,3 @@ > obj-$(CONFIG_6LOWPAN) := 6lowpan.o > > -6lowpan-y := iphc.o > +6lowpan-y := iphc.o nhc.o > diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c > new file mode 100644 > index 0000000..f64b244 > --- /dev/null > +++ b/net/6lowpan/nhc.c > @@ -0,0 +1,175 @@ > +/* > + * 6LoWPAN next header compression > + * > + * > + * Authors: > + * Alexander Aring > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License > + * as published by the Free Software Foundation; either version > + * 2 of the License, or (at your option) any later version. > + */ > + > +#include > + > +#include > + > +#include "nhc.h" > + > +static struct rb_root rb_root = RB_ROOT; > +static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX]; > + > +static int lowpan_nhc_insert(struct lowpan_nhc *nhc) > +{ > + struct rb_node **new = &rb_root.rb_node, *parent = NULL; > + > + /* Figure out where to put new node */ > + while (*new) { > + struct lowpan_nhc *this = container_of(*new, struct lowpan_nhc, > + node); > + int result, len_dif, len; > + > + len_dif = nhc->idlen - this->idlen; > + > + if (nhc->idlen < this->idlen) > + len = nhc->idlen; > + else > + len = this->idlen; > + > + result = memcmp(nhc->id, this->id, len); > + if (!result) > + result = len_dif; > + > + parent = *new; > + if (result < 0) > + new = &((*new)->rb_left); > + else if (result > 0) > + new = &((*new)->rb_right); > + else > + return -EEXIST; > + } > + > + /* Add new node and rebalance tree. */ > + rb_link_node(&nhc->node, parent, new); > + rb_insert_color(&nhc->node, &rb_root); > + > + return 0; > +} > + > +static void lowpan_nhc_remove(struct lowpan_nhc *nhc) > +{ > + rb_erase(&nhc->node, &rb_root); > +} > + > +struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb) > +{ > + struct rb_node *node = rb_root.rb_node; > + const u8 *nhcid_skb_ptr = skb->data; > + > + while (node) { > + struct lowpan_nhc *nhc = container_of(node, struct lowpan_nhc, > + node); > + u8 nhcid_skb_ptr_masked[LOWPAN_NHC_MAX_ID_LEN]; > + int result, i; > + > + if (nhcid_skb_ptr + nhc->idlen > skb->data + skb->len) > + return NULL; > + > + /* copy and mask afterwards the nhid value from skb */ > + memcpy(nhcid_skb_ptr_masked, nhcid_skb_ptr, nhc->idlen); > + for (i = 0; i < nhc->idlen; i++) > + nhcid_skb_ptr_masked[i] &= nhc->idmask[i]; > + > + result = memcmp(nhcid_skb_ptr_masked, nhc->id, nhc->idlen); > + if (result < 0) > + node = node->rb_left; > + else if (result > 0) > + node = node->rb_right; > + else > + return nhc; > + } > + > + return NULL; > +} > + > +struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr) > +{ > + return lowpan_nexthdr_nhcs[nexthdr]; > +} > + > +int lowpan_nhc_do_compression(struct lowpan_nhc *nhc, struct sk_buff *skb, > + u8 **hc_ptr, u8 *iphc0) > +{ > + int ret; > + > + if (!nhc) > + return 0; > + > + ret = nhc->compress(skb, hc_ptr); > + if (ret == 0) > + *iphc0 |= LOWPAN_IPHC_NH_C; > + > + return ret; > +} > + > +int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct ipv6hdr *hdr) > +{ > + struct lowpan_nhc *nhc; > + /* default dropping if nothing found */ > + int ret = 0; > + this should be ret = -ENOENT; To avoid sending garbage to next higher layer. I changed this is here from -EINVAL to 0. Sorry some mistake is happend here, now it's real dropped afterwards. > + nhc = lowpan_nhc_by_nhcid(skb); > + if (nhc) { > + ret = nhc->uncompress(skb, sizeof(*hdr) + nhc->nexthdrlen); > + if (ret == 0) { > + hdr->nexthdr = nhc->nexthdr; > + skb_reset_transport_header(skb); > + raw_dump_table(__func__, "raw transport header dump", > + skb_transport_header(skb), > + nhc->nexthdrlen); > + } else if (ret == -ENOTSUPP) { > + netdev_warn(skb->dev, "received %s which is not supported for uncompression.\n", > + nhc->name); > + } > + } else { > + netdev_warn(skb->dev, "received nhc which is not supported. Dropping.\n"); > + } > + > + return ret; > +} > + - Alex