From mboxrd@z Thu Jan 1 00:00:00 1970 From: Davide Caratti Subject: [PATCH RFC net-next v3 2/7] net: introduce skb_crc32c_csum_help Date: Fri, 7 Apr 2017 16:16:05 +0200 Message-ID: <83b81e265a9d10b28bb26b24d2d2f6b483b27b65.1491562390.git.dcaratti@redhat.com> References: Cc: Linux Kernel Network Developers , linux-sctp@vger.kernel.org To: Tom Herbert , Alexander Duyck , David Laight , "David S . Miller" , Marcelo Ricardo Leitner Return-path: Received: from mx1.redhat.com ([209.132.183.28]:8754 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933598AbdDGOQd (ORCPT ); Fri, 7 Apr 2017 10:16:33 -0400 In-Reply-To: In-Reply-To: References: Sender: netdev-owner@vger.kernel.org List-ID: skb_crc32c_csum_help is like skb_checksum_help, but it is designed for checksumming SCTP packets using crc32c (see RFC3309), provided that libcrc32c.ko has been loaded before. In case libcrc32c is not loaded, invoking skb_crc32c_csum_help on a skb results in one the following printouts: warn_crc32c_csum_update: attempt to compute crc32c without libcrc32c.ko warn_crc32c_csum_combine: attempt to compute crc32c without libcrc32c.ko Signed-off-by: Davide Caratti --- include/linux/netdevice.h | 1 + include/linux/skbuff.h | 3 ++- net/core/dev.c | 40 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cc07c3b..e86b50e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3899,6 +3899,7 @@ void netdev_rss_key_fill(void *buffer, size_t len); int dev_get_nest_level(struct net_device *dev); int skb_checksum_help(struct sk_buff *skb); +int skb_crc32c_csum_help(struct sk_buff *skb); struct sk_buff *__skb_gso_segment(struct sk_buff *skb, netdev_features_t features, bool tx_path); struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb, diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8e9dd82..d18b31d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -193,7 +193,8 @@ * accordingly. Note the there is no indication in the skbuff that the * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports * both IP checksum offload and SCTP CRC offload must verify which offload - * is configured for a packet presumably by inspecting packet headers. + * is configured for a packet presumably by inspecting packet headers; in + * case, skb_crc32c_csum_help is provided to compute CRC on SCTP packets. * * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of * offloading the FCOE CRC in a packet. To perform this offload the stack diff --git a/net/core/dev.c b/net/core/dev.c index ef9fe60e..7d59cba 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -140,6 +140,7 @@ #include #include #include +#include #include "net-sysfs.h" @@ -2606,6 +2607,45 @@ int skb_checksum_help(struct sk_buff *skb) } EXPORT_SYMBOL(skb_checksum_help); +int skb_crc32c_csum_help(struct sk_buff *skb) +{ + __le32 crc32c_csum; + int ret = 0, offset; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + goto out; + + if (unlikely(skb_is_gso(skb))) + goto out; + + /* Before computing a checksum, we should make sure no frag could + * be modified by an external entity : checksum could be wrong. + */ + if (unlikely(skb_has_shared_frag(skb))) { + ret = __skb_linearize(skb); + if (ret) + goto out; + } + + offset = skb_checksum_start_offset(skb); + crc32c_csum = cpu_to_le32(~__skb_checksum(skb, offset, + skb->len - offset, ~(__u32)0, + crc32c_csum_stub)); + offset += offsetof(struct sctphdr, checksum); + BUG_ON(offset >= skb_headlen(skb)); + + if (skb_cloned(skb) && + !skb_clone_writable(skb, offset + sizeof(__le32))) { + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); + if (ret) + goto out; + } + *(__le32 *)(skb->data + offset) = crc32c_csum; + skb->ip_summed = CHECKSUM_NONE; +out: + return ret; +} + __be16 skb_network_protocol(struct sk_buff *skb, int *depth) { __be16 type = skb->protocol; -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Davide Caratti Date: Fri, 07 Apr 2017 14:16:05 +0000 Subject: [PATCH RFC net-next v3 2/7] net: introduce skb_crc32c_csum_help Message-Id: <83b81e265a9d10b28bb26b24d2d2f6b483b27b65.1491562390.git.dcaratti@redhat.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tom Herbert , Alexander Duyck , David Laight , "David S . Miller" , Marcelo Ricardo Leitner Cc: Linux Kernel Network Developers , linux-sctp@vger.kernel.org skb_crc32c_csum_help is like skb_checksum_help, but it is designed for checksumming SCTP packets using crc32c (see RFC3309), provided that libcrc32c.ko has been loaded before. In case libcrc32c is not loaded, invoking skb_crc32c_csum_help on a skb results in one the following printouts: warn_crc32c_csum_update: attempt to compute crc32c without libcrc32c.ko warn_crc32c_csum_combine: attempt to compute crc32c without libcrc32c.ko Signed-off-by: Davide Caratti --- include/linux/netdevice.h | 1 + include/linux/skbuff.h | 3 ++- net/core/dev.c | 40 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 43 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index cc07c3b..e86b50e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3899,6 +3899,7 @@ void netdev_rss_key_fill(void *buffer, size_t len); int dev_get_nest_level(struct net_device *dev); int skb_checksum_help(struct sk_buff *skb); +int skb_crc32c_csum_help(struct sk_buff *skb); struct sk_buff *__skb_gso_segment(struct sk_buff *skb, netdev_features_t features, bool tx_path); struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb, diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8e9dd82..d18b31d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -193,7 +193,8 @@ * accordingly. Note the there is no indication in the skbuff that the * CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports * both IP checksum offload and SCTP CRC offload must verify which offload - * is configured for a packet presumably by inspecting packet headers. + * is configured for a packet presumably by inspecting packet headers; in + * case, skb_crc32c_csum_help is provided to compute CRC on SCTP packets. * * NETIF_F_FCOE_CRC - This feature indicates that a device is capable of * offloading the FCOE CRC in a packet. To perform this offload the stack diff --git a/net/core/dev.c b/net/core/dev.c index ef9fe60e..7d59cba 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -140,6 +140,7 @@ #include #include #include +#include #include "net-sysfs.h" @@ -2606,6 +2607,45 @@ int skb_checksum_help(struct sk_buff *skb) } EXPORT_SYMBOL(skb_checksum_help); +int skb_crc32c_csum_help(struct sk_buff *skb) +{ + __le32 crc32c_csum; + int ret = 0, offset; + + if (skb->ip_summed != CHECKSUM_PARTIAL) + goto out; + + if (unlikely(skb_is_gso(skb))) + goto out; + + /* Before computing a checksum, we should make sure no frag could + * be modified by an external entity : checksum could be wrong. + */ + if (unlikely(skb_has_shared_frag(skb))) { + ret = __skb_linearize(skb); + if (ret) + goto out; + } + + offset = skb_checksum_start_offset(skb); + crc32c_csum = cpu_to_le32(~__skb_checksum(skb, offset, + skb->len - offset, ~(__u32)0, + crc32c_csum_stub)); + offset += offsetof(struct sctphdr, checksum); + BUG_ON(offset >= skb_headlen(skb)); + + if (skb_cloned(skb) && + !skb_clone_writable(skb, offset + sizeof(__le32))) { + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); + if (ret) + goto out; + } + *(__le32 *)(skb->data + offset) = crc32c_csum; + skb->ip_summed = CHECKSUM_NONE; +out: + return ret; +} + __be16 skb_network_protocol(struct sk_buff *skb, int *depth) { __be16 type = skb->protocol; -- 2.7.4