From 7c967b224a9a7061009ccbc47e1a0b605f1b6d81 Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Tue, 25 Nov 2014 11:21:19 -0800 Subject: net: Add remcsum_adjust as common function for remote checksum offload This function does the work to update a checksum field as part of remote checksum offload. remcsum_adjust does the following: 1) Subtract out the calculated checksum from the beginning of the packet (ptr arg) to the start offset. 2) Adjust the checksum field indicated by offset based on the modified checksum value from above step. 3) Return the difference in the old checksum field value and the new one. The caller will use this to update skb->csum and NAPI csum. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/net/checksum.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/include/net/checksum.h b/include/net/checksum.h index 6465bae80a4f..e339a9513e29 100644 --- a/include/net/checksum.h +++ b/include/net/checksum.h @@ -151,4 +151,20 @@ static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, (__force __be32)to, pseudohdr); } +static inline __wsum remcsum_adjust(void *ptr, __wsum csum, + int start, int offset) +{ + __sum16 *psum = (__sum16 *)(ptr + offset); + __wsum delta; + + /* Subtract out checksum up to start */ + csum = csum_sub(csum, csum_partial(ptr, start, 0)); + + /* Set derived checksum in packet */ + delta = csum_sub(csum_fold(csum), *psum); + *psum = csum_fold(csum); + + return delta; +} + #endif -- cgit v1.2.3 From 4fd671ded14f92cb8db0bf72747f4df508ba5e3d Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Tue, 25 Nov 2014 11:21:20 -0800 Subject: gue: Call remcsum_adjust Change remote checksum offload to call remcsum_adjust. This also eliminates the optimization to skip an IP header as part of the adjustment (really does not seem to be much of a win). Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/fou.c | 84 ++++++++++++---------------------------------------------- 1 file changed, 17 insertions(+), 67 deletions(-) diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index 3dfe9828e7ef..b986298a7ba3 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -64,15 +64,13 @@ static int fou_udp_recv(struct sock *sk, struct sk_buff *skb) } static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr, - void *data, int hdrlen, u8 ipproto) + void *data, size_t hdrlen, u8 ipproto) { __be16 *pd = data; - u16 start = ntohs(pd[0]); - u16 offset = ntohs(pd[1]); - u16 poffset = 0; - u16 plen; - __wsum csum, delta; - __sum16 *psum; + size_t start = ntohs(pd[0]); + size_t offset = ntohs(pd[1]); + size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start); + __wsum delta; if (skb->remcsum_offload) { /* Already processed in GRO path */ @@ -80,35 +78,15 @@ static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr, return guehdr; } - if (start > skb->len - hdrlen || - offset > skb->len - hdrlen - sizeof(u16)) - return NULL; - - if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) - __skb_checksum_complete(skb); - - plen = hdrlen + offset + sizeof(u16); if (!pskb_may_pull(skb, plen)) return NULL; guehdr = (struct guehdr *)&udp_hdr(skb)[1]; - if (ipproto == IPPROTO_IP && sizeof(struct iphdr) < plen) { - struct iphdr *ip = (struct iphdr *)(skb->data + hdrlen); - - /* If next header happens to be IP we can skip that for the - * checksum calculation since the IP header checksum is zero - * if correct. - */ - poffset = ip->ihl * 4; - } - - csum = csum_sub(skb->csum, skb_checksum(skb, poffset + hdrlen, - start - poffset - hdrlen, 0)); + if (unlikely(skb->ip_summed != CHECKSUM_COMPLETE)) + __skb_checksum_complete(skb); - /* Set derived checksum in packet */ - psum = (__sum16 *)(skb->data + hdrlen + offset); - delta = csum_sub(csum_fold(csum), *psum); - *psum = csum_fold(csum); + delta = remcsum_adjust((void *)guehdr + hdrlen, + skb->csum, start, offset); /* Adjust skb->csum since we changed the packet */ skb->csum = csum_add(skb->csum, delta); @@ -158,9 +136,6 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb) ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len); - /* Pull UDP header now, skb->data points to guehdr */ - __skb_pull(skb, sizeof(struct udphdr)); - /* Pull csum through the guehdr now . This can be used if * there is a remote checksum offload. */ @@ -188,7 +163,7 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb) if (unlikely(guehdr->control)) return gue_control_message(skb, guehdr); - __skb_pull(skb, hdrlen); + __skb_pull(skb, sizeof(struct udphdr) + hdrlen); skb_reset_transport_header(skb); return -guehdr->proto_ctype; @@ -248,24 +223,17 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off, size_t hdrlen, u8 ipproto) { __be16 *pd = data; - u16 start = ntohs(pd[0]); - u16 offset = ntohs(pd[1]); - u16 poffset = 0; - u16 plen; - void *ptr; - __wsum csum, delta; - __sum16 *psum; + size_t start = ntohs(pd[0]); + size_t offset = ntohs(pd[1]); + size_t plen = hdrlen + max_t(size_t, offset + sizeof(u16), start); + __wsum delta; if (skb->remcsum_offload) return guehdr; - if (start > skb_gro_len(skb) - hdrlen || - offset > skb_gro_len(skb) - hdrlen - sizeof(u16) || - !NAPI_GRO_CB(skb)->csum_valid || skb->remcsum_offload) + if (!NAPI_GRO_CB(skb)->csum_valid) return NULL; - plen = hdrlen + offset + sizeof(u16); - /* Pull checksum that will be written */ if (skb_gro_header_hard(skb, off + plen)) { guehdr = skb_gro_header_slow(skb, off + plen, off); @@ -273,26 +241,8 @@ static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off, return NULL; } - ptr = (void *)guehdr + hdrlen; - - if (ipproto == IPPROTO_IP && - (hdrlen + sizeof(struct iphdr) < plen)) { - struct iphdr *ip = (struct iphdr *)(ptr + hdrlen); - - /* If next header happens to be IP we can skip - * that for the checksum calculation since the - * IP header checksum is zero if correct. - */ - poffset = ip->ihl * 4; - } - - csum = csum_sub(NAPI_GRO_CB(skb)->csum, - csum_partial(ptr + poffset, start - poffset, 0)); - - /* Set derived checksum in packet */ - psum = (__sum16 *)(ptr + offset); - delta = csum_sub(csum_fold(csum), *psum); - *psum = csum_fold(csum); + delta = remcsum_adjust((void *)guehdr + hdrlen, + NAPI_GRO_CB(skb)->csum, start, offset); /* Adjust skb->csum since we changed the packet */ skb->csum = csum_add(skb->csum, delta); -- cgit v1.2.3