From 7e2b10c1e52ca37fb522be49f4be367f9311d0cd Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 4 Jun 2014 17:20:02 -0700 Subject: net: Support for multiple checksums with gso When creating a GSO packet segment we may need to set more than one checksum in the packet (for instance a TCP checksum and UDP checksum for VXLAN encapsulation). To be efficient, we want to do checksum calculation for any part of the packet at most once. This patch adds csum_start offset to skb_gso_cb. This tracks the starting offset for skb->csum which is initially set in skb_segment. When a protocol needs to compute a transport checksum it calls gso_make_checksum which computes the checksum value from the start of transport header to csum_start and then adds in skb->csum to get the full checksum. skb->csum and csum_start are then updated to reflect the checksum of the resultant packet starting from the transport header. This patch also adds a flag to skbuff, encap_hdr_csum, which is set in *gso_segment fucntions to indicate that a tunnel protocol needs checksum calculation Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/skbuff.h | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 7a9beeb1c458..d8d397acb52c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -567,7 +567,8 @@ struct sk_buff { * headers if needed */ __u8 encapsulation:1; - /* 6/8 bit hole (depending on ndisc_nodetype presence) */ + __u8 encap_hdr_csum:1; + /* 5/7 bit hole (depending on ndisc_nodetype presence) */ kmemcheck_bitfield_end(flags2); #if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL @@ -2988,6 +2989,7 @@ static inline struct sec_path *skb_sec_path(struct sk_buff *skb) struct skb_gso_cb { int mac_offset; int encap_level; + __u16 csum_start; }; #define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb) @@ -3012,6 +3014,28 @@ static inline int gso_pskb_expand_head(struct sk_buff *skb, int extra) return 0; } +/* Compute the checksum for a gso segment. First compute the checksum value + * from the start of transport header to SKB_GSO_CB(skb)->csum_start, and + * then add in skb->csum (checksum from csum_start to end of packet). + * skb->csum and csum_start are then updated to reflect the checksum of the + * resultant packet starting from the transport header-- the resultant checksum + * is in the res argument (i.e. normally zero or ~ of checksum of a pseudo + * header. + */ +static inline __sum16 gso_make_checksum(struct sk_buff *skb, __wsum res) +{ + int plen = SKB_GSO_CB(skb)->csum_start - skb_headroom(skb) - + skb_transport_offset(skb); + __u16 csum; + + csum = csum_fold(csum_partial(skb_transport_header(skb), + plen, skb->csum)); + skb->csum = res; + SKB_GSO_CB(skb)->csum_start -= plen; + + return csum; +} + static inline bool skb_is_gso(const struct sk_buff *skb) { return skb_shinfo(skb)->gso_size; -- cgit v1.2.3 From 0f4f4ffa7b7c3d29d0537a126145c9f8d8ed5dbc Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 4 Jun 2014 17:20:16 -0700 Subject: net: Add GSO support for UDP tunnels with checksum Added a new netif feature for GSO_UDP_TUNNEL_CSUM. This indicates that a device is capable of computing the UDP checksum in the encapsulating header of a UDP tunnel. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/netdev_features.h | 1 + include/linux/skbuff.h | 2 ++ 2 files changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h index c26d0ec2ef3a..f1338e0f9866 100644 --- a/include/linux/netdev_features.h +++ b/include/linux/netdev_features.h @@ -45,6 +45,7 @@ enum { NETIF_F_GSO_IPIP_BIT, /* ... IPIP tunnel with TSO */ NETIF_F_GSO_SIT_BIT, /* ... SIT tunnel with TSO */ NETIF_F_GSO_UDP_TUNNEL_BIT, /* ... UDP TUNNEL with TSO */ + NETIF_F_GSO_UDP_TUNNEL_CSUM_BIT,/* ... UDP TUNNEL with TSO & CSUM */ NETIF_F_GSO_MPLS_BIT, /* ... MPLS segmentation */ /**/NETIF_F_GSO_LAST = /* last bit, see GSO_MASK */ NETIF_F_GSO_MPLS_BIT, diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index d8d397acb52c..5a6d10a538f5 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -345,6 +345,8 @@ enum { SKB_GSO_UDP_TUNNEL = 1 << 9, SKB_GSO_MPLS = 1 << 10, + + SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11, }; #if BITS_PER_LONG > 32 -- cgit v1.2.3 From 4749c09c37030ccdc44aecebe0f71b02a377fc14 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 4 Jun 2014 17:20:23 -0700 Subject: gre: Call gso_make_checksum Call gso_make_checksum. This should have the benefit of using a checksum that may have been previously computed for the packet. This also adds NETIF_F_GSO_GRE_CSUM to differentiate devices that offload GRE GSO with and without the GRE checksum offloaed. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/netdev_features.h | 2 ++ include/linux/skbuff.h | 2 ++ 2 files changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h index f1338e0f9866..e5a589435e2b 100644 --- a/include/linux/netdev_features.h +++ b/include/linux/netdev_features.h @@ -42,6 +42,7 @@ enum { NETIF_F_TSO6_BIT, /* ... TCPv6 segmentation */ NETIF_F_FSO_BIT, /* ... FCoE segmentation */ NETIF_F_GSO_GRE_BIT, /* ... GRE with TSO */ + NETIF_F_GSO_GRE_CSUM_BIT, /* ... GRE with csum with TSO */ NETIF_F_GSO_IPIP_BIT, /* ... IPIP tunnel with TSO */ NETIF_F_GSO_SIT_BIT, /* ... SIT tunnel with TSO */ NETIF_F_GSO_UDP_TUNNEL_BIT, /* ... UDP TUNNEL with TSO */ @@ -112,6 +113,7 @@ enum { #define NETIF_F_RXFCS __NETIF_F(RXFCS) #define NETIF_F_RXALL __NETIF_F(RXALL) #define NETIF_F_GSO_GRE __NETIF_F(GSO_GRE) +#define NETIF_F_GSO_GRE_CSUM __NETIF_F(GSO_GRE_CSUM) #define NETIF_F_GSO_IPIP __NETIF_F(GSO_IPIP) #define NETIF_F_GSO_SIT __NETIF_F(GSO_SIT) #define NETIF_F_GSO_UDP_TUNNEL __NETIF_F(GSO_UDP_TUNNEL) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5a6d10a538f5..c705808bef9c 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -347,6 +347,8 @@ enum { SKB_GSO_MPLS = 1 << 10, SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11, + + SKB_GSO_GRE_CSUM = 1 << 12, }; #if BITS_PER_LONG > 32 -- cgit v1.2.3