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Date: Fri, 22 Aug 2014 13:33:47 -0700 (PDT)
From: Tom Herbert <therbert@...gle.com>
To: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH v2 net-next 1/6] 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 <therbert@...gle.com>
---
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 3837739..0fac884 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;
@@ -2153,11 +2159,77 @@ 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 b65a505..2a0d416 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3963,7 +3963,13 @@ 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) {
@@ -3976,6 +3982,7 @@ 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;
@@ -4206,6 +4213,31 @@ 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.
--
2.1.0.rc2.206.gedb03e5
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