From 9617813dba5b6c112922c60cd2bc57c6e11ae907 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:37 +0200 Subject: skbuff: add stub to help computing crc32c on SCTP packets sctp_compute_checksum requires crc32c symbol (provided by libcrc32c), so it can't be used in net core. Like it has been done previously with other symbols (e.g. ipv6_dst_lookup), introduce a stub struct skb_checksum_ops to allow computation of crc32c checksum in net core after sctp.ko (and thus libcrc32c) has been loaded. Signed-off-by: Davide Caratti Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ net/core/skbuff.c | 26 ++++++++++++++++++++++++++ net/sctp/offload.c | 6 ++++++ 3 files changed, 34 insertions(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 7c0cb2ce8b01..b1f46a0d18e2 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -3076,6 +3076,8 @@ struct skb_checksum_ops { __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len); }; +extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly; + __wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, __wsum csum, const struct skb_checksum_ops *ops); __wsum skb_checksum(const struct sk_buff *skb, int offset, int len, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 346d3e85dfbc..d5c98117cbce 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2243,6 +2243,32 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, } EXPORT_SYMBOL(skb_copy_and_csum_bits); +static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum) +{ + net_warn_ratelimited( + "%s: attempt to compute crc32c without libcrc32c.ko\n", + __func__); + return 0; +} + +static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2, + int offset, int len) +{ + net_warn_ratelimited( + "%s: attempt to compute crc32c without libcrc32c.ko\n", + __func__); + return 0; +} + +static const struct skb_checksum_ops default_crc32c_ops = { + .update = warn_crc32c_csum_update, + .combine = warn_crc32c_csum_combine, +}; + +const struct skb_checksum_ops *crc32c_csum_stub __read_mostly = + &default_crc32c_ops; +EXPORT_SYMBOL(crc32c_csum_stub); + /** * skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy() * @from: source buffer diff --git a/net/sctp/offload.c b/net/sctp/offload.c index 4f5a2b580aa5..b67198429db5 100644 --- a/net/sctp/offload.c +++ b/net/sctp/offload.c @@ -98,6 +98,11 @@ static const struct net_offload sctp6_offload = { }, }; +static const struct skb_checksum_ops crc32c_csum_ops = { + .update = sctp_csum_update, + .combine = sctp_csum_combine, +}; + int __init sctp_offload_init(void) { int ret; @@ -110,6 +115,7 @@ int __init sctp_offload_init(void) if (ret) goto ipv4; + crc32c_csum_stub = &crc32c_csum_ops; return ret; ipv4: -- cgit From b72b5bf6a8fc9065f270ae135bbd47abb9d96790 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:38 +0200 Subject: net: introduce skb_crc32c_csum_help 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 Signed-off-by: David S. Miller --- include/linux/netdevice.h | 1 + include/linux/skbuff.h | 3 ++- net/core/dev.c | 41 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 44 insertions(+), 1 deletion(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 0150b2dd3031..abbc72e09f11 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3931,6 +3931,7 @@ 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 b1f46a0d18e2..62d62964c743 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 acd594c56f0a..8356d5f05f89 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -143,6 +143,7 @@ #include #include #include +#include #include "net-sysfs.h" @@ -2612,6 +2613,46 @@ out: } EXPORT_SYMBOL(skb_checksum_help); +int skb_crc32c_csum_help(struct sk_buff *skb) +{ + __le32 crc32c_csum; + int ret = 0, offset, start; + + 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; + } + start = skb_checksum_start_offset(skb); + offset = start + offsetof(struct sctphdr, checksum); + if (WARN_ON_ONCE(offset >= skb_headlen(skb))) { + ret = -EINVAL; + goto out; + } + if (skb_cloned(skb) && + !skb_clone_writable(skb, offset + sizeof(__le32))) { + ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC); + if (ret) + goto out; + } + crc32c_csum = cpu_to_le32(~__skb_checksum(skb, start, + skb->len - start, ~(__u32)0, + crc32c_csum_stub)); + *(__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; -- cgit From 219f1d79871257e9603f504dce0fe8ebf47aad08 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:39 +0200 Subject: sk_buff: remove support for csum_bad in sk_buff This bit was introduced with commit 5a21232983aa ("net: Support for csum_bad in skbuff") to reduce the stack workload when processing RX packets carrying a wrong Internet Checksum. Up to now, only one driver and GRO core are setting it. Suggested-by: Tom Herbert Signed-off-by: Davide Caratti Signed-off-by: David S. Miller --- drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 2 +- include/linux/netdevice.h | 4 +--- include/linux/skbuff.h | 23 ++--------------------- net/bridge/netfilter/nft_reject_bridge.c | 5 +---- net/core/dev.c | 3 --- net/ipv4/netfilter/nf_reject_ipv4.c | 2 +- net/ipv6/netfilter/nf_reject_ipv6.c | 3 --- 7 files changed, 6 insertions(+), 36 deletions(-) diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c index 3a8a4aa13687..9a0817938eca 100644 --- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c +++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c @@ -223,7 +223,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self, int *work_done, int budget) skb->protocol = eth_type_trans(skb, ndev); if (unlikely(buff->is_cso_err)) { ++self->stats.rx.errors; - __skb_mark_checksum_bad(skb); + skb->ip_summed = CHECKSUM_NONE; } else { if (buff->is_ip_cso) { __skb_incr_checksum_unnecessary(skb); diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index abbc72e09f11..c1611ace5336 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2573,9 +2573,7 @@ static inline void skb_gro_incr_csum_unnecessary(struct sk_buff *skb) if (__skb_gro_checksum_validate_needed(skb, zero_okay, check)) \ __ret = __skb_gro_checksum_validate_complete(skb, \ compute_pseudo(skb, proto)); \ - if (__ret) \ - __skb_mark_checksum_bad(skb); \ - else \ + if (!__ret) \ skb_gro_incr_csum_unnecessary(skb); \ __ret; \ }) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 62d62964c743..c38f890d425e 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -685,7 +685,7 @@ struct sk_buff { __u8 csum_valid:1; __u8 csum_complete_sw:1; __u8 csum_level:2; - __u8 csum_bad:1; + __u8 __csum_bad_unused:1; /* one bit hole */ __u8 dst_pending_confirm:1; #ifdef CONFIG_IPV6_NDISC_NODETYPE @@ -3336,21 +3336,6 @@ static inline void __skb_incr_checksum_unnecessary(struct sk_buff *skb) } } -static inline void __skb_mark_checksum_bad(struct sk_buff *skb) -{ - /* Mark current checksum as bad (typically called from GRO - * path). In the case that ip_summed is CHECKSUM_NONE - * this must be the first checksum encountered in the packet. - * When ip_summed is CHECKSUM_UNNECESSARY, this is the first - * checksum after the last one validated. For UDP, a zero - * checksum can not be marked as bad. - */ - - if (skb->ip_summed == CHECKSUM_NONE || - skb->ip_summed == CHECKSUM_UNNECESSARY) - skb->csum_bad = 1; -} - /* Check if we need to perform checksum complete validation. * * Returns true if checksum complete is needed, false otherwise @@ -3404,9 +3389,6 @@ static inline __sum16 __skb_checksum_validate_complete(struct sk_buff *skb, skb->csum_valid = 1; return 0; } - } else if (skb->csum_bad) { - /* ip_summed == CHECKSUM_NONE in this case */ - return (__force __sum16)1; } skb->csum = psum; @@ -3466,8 +3448,7 @@ static inline __wsum null_compute_pseudo(struct sk_buff *skb, int proto) static inline bool __skb_checksum_convert_check(struct sk_buff *skb) { - return (skb->ip_summed == CHECKSUM_NONE && - skb->csum_valid && !skb->csum_bad); + return (skb->ip_summed == CHECKSUM_NONE && skb->csum_valid); } static inline void __skb_checksum_convert(struct sk_buff *skb, diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index 346ef6b00b8f..c16dd3a47fc6 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -111,7 +111,7 @@ static void nft_reject_br_send_v4_unreach(struct net *net, __wsum csum; u8 proto; - if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb)) + if (!nft_bridge_iphdr_validate(oldskb)) return; /* IP header checks: fragment. */ @@ -226,9 +226,6 @@ static bool reject6_br_csum_ok(struct sk_buff *skb, int hook) __be16 fo; u8 proto = ip6h->nexthdr; - if (skb->csum_bad) - return false; - if (skb_csum_unnecessary(skb)) return true; diff --git a/net/core/dev.c b/net/core/dev.c index 8356d5f05f89..f0281ff45e77 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4678,9 +4678,6 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff if (netif_elide_gro(skb->dev)) goto normal; - if (skb->csum_bad) - goto normal; - gro_list_prepare(napi, skb); rcu_read_lock(); diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index 7cd8d0d918f8..6f8d9e5e062b 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -172,7 +172,7 @@ void nf_send_unreach(struct sk_buff *skb_in, int code, int hook) struct iphdr *iph = ip_hdr(skb_in); u8 proto; - if (skb_in->csum_bad || iph->frag_off & htons(IP_OFFSET)) + if (iph->frag_off & htons(IP_OFFSET)) return; if (skb_csum_unnecessary(skb_in)) { diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c index eedee5d108d9..f63b18e05c69 100644 --- a/net/ipv6/netfilter/nf_reject_ipv6.c +++ b/net/ipv6/netfilter/nf_reject_ipv6.c @@ -220,9 +220,6 @@ static bool reject6_csum_ok(struct sk_buff *skb, int hook) __be16 fo; u8 proto; - if (skb->csum_bad) - return false; - if (skb_csum_unnecessary(skb)) return true; -- cgit From dba003067a43a9699bef0c4bdbe320ece5a109b8 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:40 +0200 Subject: net: use skb->csum_not_inet to identify packets needing crc32c skb->csum_not_inet carries the indication on which algorithm is needed to compute checksum on skb in the transmit path, when skb->ip_summed is equal to CHECKSUM_PARTIAL. If skb carries a SCTP packet and crc32c hasn't been yet written in L4 header, skb->csum_not_inet is assigned to 1; otherwise, assume Internet Checksum is needed and thus set skb->csum_not_inet to 0. Suggested-by: Tom Herbert Signed-off-by: Davide Caratti Acked-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/skbuff.h | 16 +++++++++------- net/core/dev.c | 1 + net/sched/act_csum.c | 1 + net/sctp/offload.c | 1 + net/sctp/output.c | 1 + 5 files changed, 13 insertions(+), 7 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index c38f890d425e..a43d2086bb7f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -189,12 +189,13 @@ * * NETIF_F_SCTP_CRC - This feature indicates that a device is capable of * offloading the SCTP CRC in a packet. To perform this offload the stack - * will set ip_summed to CHECKSUM_PARTIAL and set csum_start and csum_offset - * 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; in - * case, skb_crc32c_csum_help is provided to compute CRC on SCTP packets. + * will set set csum_start and csum_offset accordingly, set ip_summed to + * CHECKSUM_PARTIAL and set csum_not_inet to 1, to provide an indication in + * the skbuff that the CHECKSUM_PARTIAL refers to CRC32c. + * A driver that supports both IP checksum offload and SCTP CRC32c offload + * must verify which offload is configured for a packet by testing the + * value of skb->csum_not_inet; skb_crc32c_csum_help is provided to resolve + * CHECKSUM_PARTIAL on skbs where csum_not_inet is set to 1. * * 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 @@ -557,6 +558,7 @@ typedef unsigned char *sk_buff_data_t; * @wifi_acked_valid: wifi_acked was set * @wifi_acked: whether frame was acked on wifi or not * @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS + * @csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL * @dst_pending_confirm: need to confirm neighbour * @napi_id: id of the NAPI struct this skb came from * @secmark: security marking @@ -685,7 +687,7 @@ struct sk_buff { __u8 csum_valid:1; __u8 csum_complete_sw:1; __u8 csum_level:2; - __u8 __csum_bad_unused:1; /* one bit hole */ + __u8 csum_not_inet:1; __u8 dst_pending_confirm:1; #ifdef CONFIG_IPV6_NDISC_NODETYPE diff --git a/net/core/dev.c b/net/core/dev.c index f0281ff45e77..71107d1f3051 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2649,6 +2649,7 @@ int skb_crc32c_csum_help(struct sk_buff *skb) crc32c_csum_stub)); *(__le32 *)(skb->data + offset) = crc32c_csum; skb->ip_summed = CHECKSUM_NONE; + skb->csum_not_inet = 0; out: return ret; } diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index ab6fdbd34db7..3317a2f579da 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -350,6 +350,7 @@ static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl, sctph->checksum = sctp_compute_cksum(skb, skb_network_offset(skb) + ihl); skb->ip_summed = CHECKSUM_NONE; + skb->csum_not_inet = 0; return 1; } diff --git a/net/sctp/offload.c b/net/sctp/offload.c index b67198429db5..275925b93b29 100644 --- a/net/sctp/offload.c +++ b/net/sctp/offload.c @@ -35,6 +35,7 @@ static __le32 sctp_gso_make_checksum(struct sk_buff *skb) { skb->ip_summed = CHECKSUM_NONE; + skb->csum_not_inet = 0; return sctp_compute_cksum(skb, skb_transport_offset(skb)); } diff --git a/net/sctp/output.c b/net/sctp/output.c index 1409a875ad8e..e2edf2ebbade 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -538,6 +538,7 @@ merge: } else { chksum: head->ip_summed = CHECKSUM_PARTIAL; + head->csum_not_inet = 1; head->csum_start = skb_transport_header(head) - head->head; head->csum_offset = offsetof(struct sctphdr, checksum); } -- cgit From 43c26a1a45938624fb9301e8bf7dfabbed293619 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:41 +0200 Subject: net: more accurate checksumming in validate_xmit_skb() skb_csum_hwoffload_help() uses netdev features and skb->csum_not_inet to determine if skb needs software computation of Internet Checksum or crc32c (or nothing, if this computation can be done by the hardware). Use it in place of skb_checksum_help() in validate_xmit_skb() to avoid corruption of non-GSO SCTP packets having skb->ip_summed equal to CHECKSUM_PARTIAL. While at it, remove references to skb_csum_off_chk* functions, since they are not present anymore in Linux _ see commit cf53b1da73bd ("Revert "net: Add driver helper functions to determine checksum offloadability""). Signed-off-by: Davide Caratti Signed-off-by: David S. Miller --- Documentation/networking/checksum-offloads.txt | 11 +++++++---- include/linux/netdevice.h | 3 +++ include/linux/skbuff.h | 13 +++++-------- net/core/dev.c | 14 ++++++++++++-- 4 files changed, 27 insertions(+), 14 deletions(-) diff --git a/Documentation/networking/checksum-offloads.txt b/Documentation/networking/checksum-offloads.txt index 56e36861245f..d52d191bbb0c 100644 --- a/Documentation/networking/checksum-offloads.txt +++ b/Documentation/networking/checksum-offloads.txt @@ -35,6 +35,9 @@ This interface only allows a single checksum to be offloaded. Where encapsulation is used, the packet may have multiple checksum fields in different header layers, and the rest will have to be handled by another mechanism such as LCO or RCO. +CRC32c can also be offloaded using this interface, by means of filling + skb->csum_start and skb->csum_offset as described above, and setting + skb->csum_not_inet: see skbuff.h comment (section 'D') for more details. No offloading of the IP header checksum is performed; it is always done in software. This is OK because when we build the IP header, we obviously have it in cache, so summing it isn't expensive. It's also rather short. @@ -49,9 +52,9 @@ A driver declares its offload capabilities in netdev->hw_features; see and csum_offset given in the SKB; if it tries to deduce these itself in hardware (as some NICs do) the driver should check that the values in the SKB match those which the hardware will deduce, and if not, fall back to - checksumming in software instead (with skb_checksum_help or one of the - skb_csum_off_chk* functions as mentioned in include/linux/skbuff.h). This - is a pain, but that's what you get when hardware tries to be clever. + checksumming in software instead (with skb_csum_hwoffload_help() or one of + the skb_checksum_help() / skb_crc32c_csum_help functions, as mentioned in + include/linux/skbuff.h). The stack should, for the most part, assume that checksum offload is supported by the underlying device. The only place that should check is @@ -60,7 +63,7 @@ The stack should, for the most part, assume that checksum offload is may include other offloads besides TX Checksum Offload) and, if they are not supported or enabled on the device (determined by netdev->features), performs the corresponding offload in software. In the case of TX - Checksum Offload, that means calling skb_checksum_help(skb). + Checksum Offload, that means calling skb_csum_hwoffload_help(skb, features). LCO: Local Checksum Offload diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index c1611ace5336..f8f7cd52a0a0 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3930,6 +3930,9 @@ 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); +int skb_csum_hwoffload_help(struct sk_buff *skb, + const netdev_features_t features); + 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 a43d2086bb7f..43d7ca07b2ff 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -162,14 +162,11 @@ * * NETIF_F_IP_CSUM and NETIF_F_IPV6_CSUM are being deprecated in favor of * NETIF_F_HW_CSUM. New devices should use NETIF_F_HW_CSUM to indicate - * checksum offload capability. If a device has limited checksum capabilities - * (for instance can only perform NETIF_F_IP_CSUM or NETIF_F_IPV6_CSUM as - * described above) a helper function can be called to resolve - * CHECKSUM_PARTIAL. The helper functions are skb_csum_off_chk*. The helper - * function takes a spec argument that describes the protocol layer that is - * supported for checksum offload and can be called for each packet. If a - * packet does not match the specification for offload, skb_checksum_help - * is called to resolve the checksum. + * checksum offload capability. + * skb_csum_hwoffload_help() can be called to resolve CHECKSUM_PARTIAL based + * on network device checksumming capabilities: if a packet does not match + * them, skb_checksum_help or skb_crc32c_help (depending on the value of + * csum_not_inet, see item D.) is called to resolve the checksum. * * CHECKSUM_NONE: * diff --git a/net/core/dev.c b/net/core/dev.c index 71107d1f3051..bb136f726890 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2996,6 +2996,17 @@ static struct sk_buff *validate_xmit_vlan(struct sk_buff *skb, return skb; } +int skb_csum_hwoffload_help(struct sk_buff *skb, + const netdev_features_t features) +{ + if (unlikely(skb->csum_not_inet)) + return !!(features & NETIF_F_SCTP_CRC) ? 0 : + skb_crc32c_csum_help(skb); + + return !!(features & NETIF_F_CSUM_MASK) ? 0 : skb_checksum_help(skb); +} +EXPORT_SYMBOL(skb_csum_hwoffload_help); + static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device *dev) { netdev_features_t features; @@ -3034,8 +3045,7 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device else skb_set_transport_header(skb, skb_checksum_start_offset(skb)); - if (!(features & NETIF_F_CSUM_MASK) && - skb_checksum_help(skb)) + if (skb_csum_hwoffload_help(skb, features)) goto out_kfree_skb; } } -- cgit From 7529390d08f07fbf9b0174c5a87600b5caa1a8e8 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:42 +0200 Subject: openvswitch: more accurate checksumming in queue_userspace_packet() if skb carries an SCTP packet and ip_summed is CHECKSUM_PARTIAL, it needs CRC32c in place of Internet Checksum: use skb_csum_hwoffload_help to avoid corrupting such packets while queueing them towards userspace. Signed-off-by: Davide Caratti Signed-off-by: David S. Miller --- net/openvswitch/datapath.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 7b17da9a94a0..9ddc9f8412a2 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -453,7 +453,7 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, /* Complete checksum if needed */ if (skb->ip_summed == CHECKSUM_PARTIAL && - (err = skb_checksum_help(skb))) + (err = skb_csum_hwoffload_help(skb, 0))) goto out; /* Older versions of OVS user space enforce alignment of the last -- cgit From b4759dcdcd8466e70f01ff07f33e17cd93131d34 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Thu, 18 May 2017 15:44:43 +0200 Subject: sk_buff.h: improve description of CHECKSUM_{COMPLETE, UNNECESSARY} Add FCoE to the list of protocols that can set CHECKSUM_UNNECESSARY; add a note to CHECKSUM_COMPLETE section to specify that it does not apply to SCTP and FCoE protocols. Suggested-by: Tom Herbert Signed-off-by: Davide Caratti Acked-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/skbuff.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 43d7ca07b2ff..1713e4b7ea9f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -109,6 +109,7 @@ * may perform further validation in this case. * GRE: only if the checksum is present in the header. * SCTP: indicates the CRC in SCTP header has been validated. + * FCOE: indicates the CRC in FC frame has been validated. * * skb->csum_level indicates the number of consecutive checksums found in * the packet minus one that have been verified as CHECKSUM_UNNECESSARY. @@ -126,8 +127,10 @@ * packet as seen by netif_rx() and fills out in skb->csum. Meaning, the * hardware doesn't need to parse L3/L4 headers to implement this. * - * Note: Even if device supports only some protocols, but is able to produce - * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY. + * Notes: + * - Even if device supports only some protocols, but is able to produce + * skb->csum, it MUST use CHECKSUM_COMPLETE, not CHECKSUM_UNNECESSARY. + * - CHECKSUM_COMPLETE is not applicable to SCTP and FCoE protocols. * * CHECKSUM_PARTIAL: * -- cgit