From 573e8fca255a27e3573b51f9b183d62641c47a3d Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 22 Aug 2014 13:33:47 -0700 Subject: [PATCH] net: skb_gro_checksum_* functions Add skb_gro_checksum_validate, skb_gro_checksum_validate_zero_check, and skb_gro_checksum_simple_validate, and __skb_gro_checksum_complete. These are the cognates of the normal checksum functions but are used in the gro_receive path and operate on GRO related fields in sk_buffs. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/netdevice.h | 76 +++++++++++++++++++++++++++++++++++++-- net/core/dev.c | 34 +++++++++++++++++- 2 files changed, 107 insertions(+), 3 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 7e2b0b8b5cd7..eb73444e1bd0 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1883,7 +1883,13 @@ struct napi_gro_cb { u16 proto; /* Used in udp_gro_receive */ - u16 udp_mark; + u8 udp_mark:1; + + /* GRO checksum is valid */ + u8 csum_valid:1; + + /* Number encapsulation layers crossed */ + u8 encapsulation; /* used to support CHECKSUM_COMPLETE for tunneling protocols */ __wsum csum; @@ -2154,11 +2160,77 @@ static inline void *skb_gro_network_header(struct sk_buff *skb) static inline void skb_gro_postpull_rcsum(struct sk_buff *skb, const void *start, unsigned int len) { - if (skb->ip_summed == CHECKSUM_COMPLETE) + if (NAPI_GRO_CB(skb)->csum_valid) NAPI_GRO_CB(skb)->csum = csum_sub(NAPI_GRO_CB(skb)->csum, csum_partial(start, len, 0)); } +/* GRO checksum functions. These are logical equivalents of the normal + * checksum functions (in skbuff.h) except that they operate on the GRO + * offsets and fields in sk_buff. + */ + +__sum16 __skb_gro_checksum_complete(struct sk_buff *skb); + +static inline bool __skb_gro_checksum_validate_needed(struct sk_buff *skb, + bool zero_okay, + __sum16 check) +{ + return (skb->ip_summed != CHECKSUM_PARTIAL && + (skb->ip_summed != CHECKSUM_UNNECESSARY || + (NAPI_GRO_CB(skb)->encapsulation > skb->encapsulation)) && + (!zero_okay || check)); +} + +static inline __sum16 __skb_gro_checksum_validate_complete(struct sk_buff *skb, + __wsum psum) +{ + if (NAPI_GRO_CB(skb)->csum_valid && + !csum_fold(csum_add(psum, NAPI_GRO_CB(skb)->csum))) + return 0; + + NAPI_GRO_CB(skb)->csum = psum; + + return __skb_gro_checksum_complete(skb); +} + +/* Update skb for CHECKSUM_UNNECESSARY when we verified a top level + * checksum or an encapsulated one during GRO. This saves work + * if we fallback to normal path with the packet. + */ +static inline void skb_gro_incr_csum_unnecessary(struct sk_buff *skb) +{ + if (skb->ip_summed == CHECKSUM_UNNECESSARY) { + if (NAPI_GRO_CB(skb)->encapsulation) + skb->encapsulation = 1; + } else if (skb->ip_summed != CHECKSUM_PARTIAL) { + skb->ip_summed = CHECKSUM_UNNECESSARY; + skb->encapsulation = 0; + } +} + +#define __skb_gro_checksum_validate(skb, proto, zero_okay, check, \ + compute_pseudo) \ +({ \ + __sum16 __ret = 0; \ + if (__skb_gro_checksum_validate_needed(skb, zero_okay, check)) \ + __ret = __skb_gro_checksum_validate_complete(skb, \ + compute_pseudo(skb, proto)); \ + if (!__ret) \ + skb_gro_incr_csum_unnecessary(skb); \ + __ret; \ +}) + +#define skb_gro_checksum_validate(skb, proto, compute_pseudo) \ + __skb_gro_checksum_validate(skb, proto, false, 0, compute_pseudo) + +#define skb_gro_checksum_validate_zero_check(skb, proto, check, \ + compute_pseudo) \ + __skb_gro_checksum_validate(skb, proto, true, check, compute_pseudo) + +#define skb_gro_checksum_simple_validate(skb) \ + __skb_gro_checksum_validate(skb, 0, false, 0, null_compute_pseudo) + static inline int dev_hard_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, const void *daddr, const void *saddr, diff --git a/net/core/dev.c b/net/core/dev.c index 1421dad4cb29..b6a718ec11c1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3962,7 +3962,13 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff goto normal; gro_list_prepare(napi, skb); - NAPI_GRO_CB(skb)->csum = skb->csum; /* Needed for CHECKSUM_COMPLETE */ + + if (skb->ip_summed == CHECKSUM_COMPLETE) { + NAPI_GRO_CB(skb)->csum = skb->csum; + NAPI_GRO_CB(skb)->csum_valid = 1; + } else { + NAPI_GRO_CB(skb)->csum_valid = 0; + } rcu_read_lock(); list_for_each_entry_rcu(ptype, head, list) { @@ -3975,6 +3981,7 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff NAPI_GRO_CB(skb)->flush = 0; NAPI_GRO_CB(skb)->free = 0; NAPI_GRO_CB(skb)->udp_mark = 0; + NAPI_GRO_CB(skb)->encapsulation = 0; pp = ptype->callbacks.gro_receive(&napi->gro_list, skb); break; @@ -4205,6 +4212,31 @@ gro_result_t napi_gro_frags(struct napi_struct *napi) } EXPORT_SYMBOL(napi_gro_frags); +/* Compute the checksum from gro_offset and return the folded value + * after adding in any pseudo checksum. + */ +__sum16 __skb_gro_checksum_complete(struct sk_buff *skb) +{ + __wsum wsum; + __sum16 sum; + + wsum = skb_checksum(skb, skb_gro_offset(skb), skb_gro_len(skb), 0); + + /* NAPI_GRO_CB(skb)->csum holds pseudo checksum */ + sum = csum_fold(csum_add(NAPI_GRO_CB(skb)->csum, wsum)); + if (likely(!sum)) { + if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && + !skb->csum_complete_sw) + netdev_rx_csum_fault(skb->dev); + } + + NAPI_GRO_CB(skb)->csum = wsum; + NAPI_GRO_CB(skb)->csum_valid = 1; + + return sum; +} +EXPORT_SYMBOL(__skb_gro_checksum_complete); + /* * net_rps_action_and_irq_enable sends any pending IPI's for rps. * Note: called with local irq disabled, but exits with local irq enabled.