From: Tom Herbert <tom@herbertland.com> To: Davide Caratti <dcaratti@redhat.com> Cc: "David S. Miller" <davem@davemloft.net>, Linux Kernel Network Developers <netdev@vger.kernel.org>, linux-sctp@vger.kernel.org, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Subject: Re: [RFC PATCH net-next 2/5] net: split skb_checksum_help Date: Mon, 23 Jan 2017 12:59:48 -0800 [thread overview] Message-ID: <CALx6S37E=OEkRego_u=oDuUgQUn9-NZLpupvbN_dge1rqF92CQ@mail.gmail.com> (raw) In-Reply-To: <532e1db70b6c40f1b1e5c60b5b51be9f3437a30b.1485177252.git.dcaratti@redhat.com> On Mon, Jan 23, 2017 at 8:52 AM, Davide Caratti <dcaratti@redhat.com> wrote: > skb_checksum_help is designed to compute the Internet Checksum only. To > avoid duplicating code when other checksumming algorithms (e.g. crc32c) > are used, separate common part from RFC1624-specific part. > > Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > Signed-off-by: Davide Caratti <dcaratti@redhat.com> > --- > net/core/dev.c | 51 +++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 35 insertions(+), 16 deletions(-) > > diff --git a/net/core/dev.c b/net/core/dev.c > index ad5959e..6742160 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -2532,13 +2532,36 @@ static void skb_warn_bad_offload(const struct sk_buff *skb) > skb_shinfo(skb)->gso_type, skb->ip_summed); > } > > -/* > - * Invalidate hardware checksum when packet is to be mangled, and > +/* compute 16-bit RFC1624 checksum and store it at skb->data + offset */ > +static int skb_rfc1624_csum(struct sk_buff *skb, int offset) > +{ > + __wsum csum; > + int ret = 0; > + > + csum = skb_checksum(skb, offset, skb->len - offset, 0); > + > + offset += skb->csum_offset; > + BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); > + > + if (skb_cloned(skb) && > + !skb_clone_writable(skb, offset + sizeof(__sum16))) { > + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); > + if (ret) > + goto out; > + } > + *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; > +out: > + return ret; > +} > + > +/* Invalidate hardware checksum when packet is to be mangled, and > * complete checksum manually on outgoing path. > + * @skb - buffer that needs checksum > + * @csum_algo(skb, offset) - function used to compute the checksum > */ > -int skb_checksum_help(struct sk_buff *skb) > +static int __skb_checksum_help(struct sk_buff *skb, > + int (*csum_algo)(struct sk_buff *, int)) > { > - __wsum csum; > int ret = 0, offset; > > if (skb->ip_summed == CHECKSUM_COMPLETE) skb_checksum_help is specific to the Internet checksum. For instance, CHECKSUM_COMPLETE can _only_ refer to Internet checksum calculation nothing else will work. Checksums and CRCs are very different things with very different processing. They are not interchangeable, have very different properties, and hence it is a mistake to try to shoe horn things so that they use a common infrastructure. It might make sense to create some CRC helper functions, but last time I checked there are so few users of CRC in skbufs I'm not even sure that would make sense. Tom > @@ -2560,24 +2583,20 @@ int skb_checksum_help(struct sk_buff *skb) > > offset = skb_checksum_start_offset(skb); > BUG_ON(offset >= skb_headlen(skb)); > - csum = skb_checksum(skb, offset, skb->len - offset, 0); > - > - offset += skb->csum_offset; > - BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); > - > - if (skb_cloned(skb) && > - !skb_clone_writable(skb, offset + sizeof(__sum16))) { > - ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); > - if (ret) > - goto out; > - } > > - *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; > + ret = csum_algo(skb, offset); > + if (ret) > + goto out; > out_set_summed: > skb->ip_summed = CHECKSUM_NONE; > out: > return ret; > } > + > +int skb_checksum_help(struct sk_buff *skb) > +{ > + return __skb_checksum_help(skb, skb_rfc1624_csum); > +} > EXPORT_SYMBOL(skb_checksum_help); > > __be16 skb_network_protocol(struct sk_buff *skb, int *depth) > -- > 2.7.4 >
WARNING: multiple messages have this Message-ID (diff)
From: Tom Herbert <tom@herbertland.com> To: Davide Caratti <dcaratti@redhat.com> Cc: "David S. Miller" <davem@davemloft.net>, Linux Kernel Network Developers <netdev@vger.kernel.org>, linux-sctp@vger.kernel.org, Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Subject: Re: [RFC PATCH net-next 2/5] net: split skb_checksum_help Date: Mon, 23 Jan 2017 20:59:48 +0000 [thread overview] Message-ID: <CALx6S37E=OEkRego_u=oDuUgQUn9-NZLpupvbN_dge1rqF92CQ@mail.gmail.com> (raw) In-Reply-To: <532e1db70b6c40f1b1e5c60b5b51be9f3437a30b.1485177252.git.dcaratti@redhat.com> On Mon, Jan 23, 2017 at 8:52 AM, Davide Caratti <dcaratti@redhat.com> wrote: > skb_checksum_help is designed to compute the Internet Checksum only. To > avoid duplicating code when other checksumming algorithms (e.g. crc32c) > are used, separate common part from RFC1624-specific part. > > Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > Signed-off-by: Davide Caratti <dcaratti@redhat.com> > --- > net/core/dev.c | 51 +++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 35 insertions(+), 16 deletions(-) > > diff --git a/net/core/dev.c b/net/core/dev.c > index ad5959e..6742160 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -2532,13 +2532,36 @@ static void skb_warn_bad_offload(const struct sk_buff *skb) > skb_shinfo(skb)->gso_type, skb->ip_summed); > } > > -/* > - * Invalidate hardware checksum when packet is to be mangled, and > +/* compute 16-bit RFC1624 checksum and store it at skb->data + offset */ > +static int skb_rfc1624_csum(struct sk_buff *skb, int offset) > +{ > + __wsum csum; > + int ret = 0; > + > + csum = skb_checksum(skb, offset, skb->len - offset, 0); > + > + offset += skb->csum_offset; > + BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); > + > + if (skb_cloned(skb) && > + !skb_clone_writable(skb, offset + sizeof(__sum16))) { > + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); > + if (ret) > + goto out; > + } > + *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; > +out: > + return ret; > +} > + > +/* Invalidate hardware checksum when packet is to be mangled, and > * complete checksum manually on outgoing path. > + * @skb - buffer that needs checksum > + * @csum_algo(skb, offset) - function used to compute the checksum > */ > -int skb_checksum_help(struct sk_buff *skb) > +static int __skb_checksum_help(struct sk_buff *skb, > + int (*csum_algo)(struct sk_buff *, int)) > { > - __wsum csum; > int ret = 0, offset; > > if (skb->ip_summed = CHECKSUM_COMPLETE) skb_checksum_help is specific to the Internet checksum. For instance, CHECKSUM_COMPLETE can _only_ refer to Internet checksum calculation nothing else will work. Checksums and CRCs are very different things with very different processing. They are not interchangeable, have very different properties, and hence it is a mistake to try to shoe horn things so that they use a common infrastructure. It might make sense to create some CRC helper functions, but last time I checked there are so few users of CRC in skbufs I'm not even sure that would make sense. Tom > @@ -2560,24 +2583,20 @@ int skb_checksum_help(struct sk_buff *skb) > > offset = skb_checksum_start_offset(skb); > BUG_ON(offset >= skb_headlen(skb)); > - csum = skb_checksum(skb, offset, skb->len - offset, 0); > - > - offset += skb->csum_offset; > - BUG_ON(offset + sizeof(__sum16) > skb_headlen(skb)); > - > - if (skb_cloned(skb) && > - !skb_clone_writable(skb, offset + sizeof(__sum16))) { > - ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); > - if (ret) > - goto out; > - } > > - *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; > + ret = csum_algo(skb, offset); > + if (ret) > + goto out; > out_set_summed: > skb->ip_summed = CHECKSUM_NONE; > out: > return ret; > } > + > +int skb_checksum_help(struct sk_buff *skb) > +{ > + return __skb_checksum_help(skb, skb_rfc1624_csum); > +} > EXPORT_SYMBOL(skb_checksum_help); > > __be16 skb_network_protocol(struct sk_buff *skb, int *depth) > -- > 2.7.4 >
next prev parent reply other threads:[~2017-01-23 20:59 UTC|newest] Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-01-23 16:52 [RFC PATCH net-next 0/5] net: improve support for SCTP checksums Davide Caratti 2017-01-23 16:52 ` Davide Caratti 2017-01-23 16:52 ` [RFC PATCH net-next 1/5] skbuff: add stub to help computing crc32c on SCTP packets Davide Caratti 2017-01-23 16:52 ` Davide Caratti 2017-01-23 16:52 ` [RFC PATCH net-next 2/5] net: split skb_checksum_help Davide Caratti 2017-01-23 16:52 ` Davide Caratti 2017-01-23 20:59 ` Tom Herbert [this message] 2017-01-23 20:59 ` Tom Herbert 2017-01-24 16:35 ` David Laight 2017-01-24 16:35 ` David Laight 2017-02-02 15:07 ` Davide Caratti 2017-02-02 15:07 ` Davide Caratti 2017-02-02 16:55 ` David Laight 2017-02-02 16:55 ` David Laight 2017-02-02 18:08 ` Tom Herbert 2017-02-02 18:08 ` Tom Herbert 2017-02-27 13:39 ` Davide Caratti 2017-02-27 13:39 ` Davide Caratti 2017-02-27 15:11 ` Tom Herbert 2017-02-27 15:11 ` Tom Herbert 2017-02-28 10:31 ` Davide Caratti 2017-02-28 10:31 ` Davide Caratti 2017-02-28 10:32 ` [PATCH RFC net-next v2 1/4] skbuff: add stub to help computing crc32c on SCTP packets Davide Caratti 2017-02-28 10:32 ` Davide Caratti 2017-02-28 10:32 ` [PATCH RFC net-next v2 2/4] net: introduce skb_sctp_csum_help Davide Caratti 2017-02-28 10:32 ` Davide Caratti 2017-02-28 10:32 ` [PATCH RFC net-next v2 3/4] net: more accurate checksumming in validate_xmit_skb Davide Caratti 2017-02-28 10:32 ` Davide Caratti 2017-02-28 19:50 ` Tom Herbert 2017-02-28 19:50 ` Tom Herbert 2017-02-28 10:32 ` [PATCH RFC net-next v2 4/4] Documentation: update notes on checksum offloading Davide Caratti 2017-02-28 10:32 ` Davide Caratti 2017-02-28 22:46 ` [PATCH RFC net-next v2 1/4] skbuff: add stub to help computing crc32c on SCTP packets Alexander Duyck 2017-02-28 22:46 ` Alexander Duyck 2017-03-01 3:17 ` Tom Herbert 2017-03-01 3:17 ` Tom Herbert 2017-03-01 10:53 ` David Laight 2017-03-01 10:53 ` David Laight 2017-03-06 21:51 ` Davide Caratti 2017-03-06 21:51 ` Davide Caratti 2017-03-07 18:06 ` Alexander Duyck 2017-03-07 18:06 ` Alexander Duyck 2017-03-18 13:17 ` Davide Caratti 2017-03-18 13:17 ` Davide Caratti 2017-03-18 22:35 ` Tom Herbert 2017-03-18 22:35 ` Tom Herbert 2017-04-07 14:16 ` [PATCH RFC net-next v3 0/7] improve CRC32c in the forwarding path Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 1/7] skbuff: add stub to help computing crc32c on SCTP packets Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 2/7] net: introduce skb_crc32c_csum_help Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 3/7] sk_buff: remove support for csum_bad in sk_buff Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 4/7] net: use skb->csum_algo to identify packets needing crc32c Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 15:43 ` Tom Herbert 2017-04-07 15:43 ` Tom Herbert 2017-04-07 17:29 ` Davide Caratti 2017-04-07 17:29 ` Davide Caratti 2017-04-07 18:11 ` Tom Herbert 2017-04-07 18:11 ` Tom Herbert 2017-04-13 10:36 ` Davide Caratti 2017-04-13 10:36 ` Davide Caratti 2017-04-20 13:38 ` [PATCH RFC net-next v4 0/7] net: improve support for SCTP checksums Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-20 13:38 ` [PATCH RFC net-next v4 1/7] skbuff: add stub to help computing crc32c on SCTP packets Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-20 13:38 ` [PATCH RFC net-next v4 2/7] net: introduce skb_crc32c_csum_help Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-27 12:29 ` Marcelo Ricardo Leitner 2017-04-27 12:29 ` Marcelo Ricardo Leitner 2017-04-20 13:38 ` [PATCH RFC net-next v4 3/7] sk_buff: remove support for csum_bad in sk_buff Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-27 1:34 ` [sk_buff] 95510aef27: BUG:Bad_page_state_in_process kernel test robot 2017-04-27 1:34 ` kernel test robot 2017-04-29 20:21 ` [PATCH RFC net-next v4 3/7] sk_buff: remove support for csum_bad in sk_buff Tom Herbert 2017-04-29 20:21 ` Tom Herbert 2017-04-20 13:38 ` [PATCH RFC net-next v4 4/7] net: use skb->csum_not_inet to identify packets needing crc32c Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-29 20:18 ` Tom Herbert 2017-04-29 20:18 ` Tom Herbert 2017-04-20 13:38 ` [PATCH RFC net-next v4 5/7] net: more accurate checksumming in validate_xmit_skb() Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-20 13:38 ` [PATCH RFC net-next v4 6/7] openvswitch: more accurate checksumming in queue_userspace_packet() Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-20 13:38 ` [PATCH RFC net-next v4 7/7] sk_buff.h: improve description of CHECKSUM_{COMPLETE,UNNECESSARY} Davide Caratti 2017-04-20 13:38 ` Davide Caratti 2017-04-29 20:20 ` Tom Herbert 2017-04-29 20:20 ` Tom Herbert 2017-04-27 12:41 ` [PATCH RFC net-next v4 0/7] net: improve support for SCTP checksums Marcelo Ricardo Leitner 2017-04-27 12:41 ` Marcelo Ricardo Leitner 2017-04-07 14:16 ` [PATCH RFC net-next v3 5/7] net: more accurate checksumming in validate_xmit_skb() Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 6/7] openvswitch: more accurate checksumming in queue_userspace_packet() Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-04-07 14:16 ` [PATCH RFC net-next v3 7/7] sk_buff.h: improve description of CHECKSUM_{COMPLETE,UNNECESSARY} Davide Caratti 2017-04-07 14:16 ` Davide Caratti 2017-01-23 16:52 ` [RFC PATCH net-next 3/5] net: introduce skb_sctp_csum_help Davide Caratti 2017-01-23 16:52 ` Davide Caratti 2017-01-23 16:52 ` [RFC PATCH net-next 4/5] net: more accurate checksumming in validate_xmit_skb Davide Caratti 2017-01-23 16:52 ` Davide Caratti 2017-01-23 16:52 ` [RFC PATCH net-next 5/5] Documentation: add description of skb_sctp_csum_help Davide Caratti 2017-01-23 16:52 ` Davide Caratti
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