From 024ec3deac33ddbd81f3c887506f132b24ea21a7 Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Thu, 25 Jul 2013 10:52:05 +0900 Subject: [PATCH] net/sctp: Refactor SCTP skb checksum computation This patch consolidates the SCTP checksum calculation code from various places to a single new function, sctp_compute_cksum(skb, offset). Signed-off-by: Joe Stringer Reviewed-by: Julian Anastasov Acked-by: Simon Horman Signed-off-by: David S. Miller --- include/net/sctp/checksum.h | 15 +++++++++++++++ net/netfilter/ipvs/ip_vs_proto_sctp.c | 23 +++-------------------- net/netfilter/nf_nat_proto_sctp.c | 8 +------- net/sctp/input.c | 10 +--------- 4 files changed, 20 insertions(+), 36 deletions(-) diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h index 78b88aa8c810..483e6303458d 100644 --- a/include/net/sctp/checksum.h +++ b/include/net/sctp/checksum.h @@ -85,4 +85,19 @@ static inline __le32 sctp_end_cksum(__u32 crc32) return cpu_to_le32(~crc32); } +/* Calculate the CRC32C checksum of an SCTP packet. */ +static inline __le32 sctp_compute_cksum(const struct sk_buff *skb, + unsigned int offset) +{ + const struct sk_buff *iter; + + __u32 crc32 = sctp_start_cksum(skb->data + offset, + skb_headlen(skb) - offset); + skb_walk_frags(skb, iter) + crc32 = sctp_update_cksum((__u8 *) iter->data, + skb_headlen(iter), crc32); + + return sctp_end_cksum(crc32); +} + #endif /* __sctp_checksum_h__ */ diff --git a/net/netfilter/ipvs/ip_vs_proto_sctp.c b/net/netfilter/ipvs/ip_vs_proto_sctp.c index 3c0da8728036..23e596e438b3 100644 --- a/net/netfilter/ipvs/ip_vs_proto_sctp.c +++ b/net/netfilter/ipvs/ip_vs_proto_sctp.c @@ -66,15 +66,7 @@ sctp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd, static void sctp_nat_csum(struct sk_buff *skb, sctp_sctphdr_t *sctph, unsigned int sctphoff) { - __u32 crc32; - struct sk_buff *iter; - - crc32 = sctp_start_cksum((__u8 *)sctph, skb_headlen(skb) - sctphoff); - skb_walk_frags(skb, iter) - crc32 = sctp_update_cksum((u8 *) iter->data, - skb_headlen(iter), crc32); - sctph->checksum = sctp_end_cksum(crc32); - + sctph->checksum = sctp_compute_cksum(skb, sctphoff); skb->ip_summed = CHECKSUM_UNNECESSARY; } @@ -151,10 +143,7 @@ sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp) { unsigned int sctphoff; struct sctphdr *sh, _sctph; - struct sk_buff *iter; - __le32 cmp; - __le32 val; - __u32 tmp; + __le32 cmp, val; #ifdef CONFIG_IP_VS_IPV6 if (af == AF_INET6) @@ -168,13 +157,7 @@ sctp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp) return 0; cmp = sh->checksum; - - tmp = sctp_start_cksum((__u8 *) sh, skb_headlen(skb)); - skb_walk_frags(skb, iter) - tmp = sctp_update_cksum((__u8 *) iter->data, - skb_headlen(iter), tmp); - - val = sctp_end_cksum(tmp); + val = sctp_compute_cksum(skb, sctphoff); if (val != cmp) { /* CRC failure, dump it. */ diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c index 396e55d46f90..754536f2c674 100644 --- a/net/netfilter/nf_nat_proto_sctp.c +++ b/net/netfilter/nf_nat_proto_sctp.c @@ -34,9 +34,7 @@ sctp_manip_pkt(struct sk_buff *skb, const struct nf_conntrack_tuple *tuple, enum nf_nat_manip_type maniptype) { - struct sk_buff *frag; sctp_sctphdr_t *hdr; - __u32 crc32; if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) return false; @@ -51,11 +49,7 @@ sctp_manip_pkt(struct sk_buff *skb, hdr->dest = tuple->dst.u.sctp.port; } - crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff); - skb_walk_frags(skb, frag) - crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag), - crc32); - hdr->checksum = sctp_end_cksum(crc32); + hdr->checksum = sctp_compute_cksum(skb, hdroff); return true; } diff --git a/net/sctp/input.c b/net/sctp/input.c index 7993495a4c0f..fa91aff02388 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -87,15 +87,7 @@ static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) { struct sctphdr *sh = sctp_hdr(skb); __le32 cmp = sh->checksum; - struct sk_buff *list; - __le32 val; - __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); - - skb_walk_frags(skb, list) - tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), - tmp); - - val = sctp_end_cksum(tmp); + __le32 val = sctp_compute_cksum(skb, 0); if (val != cmp) { /* CRC failure, dump it. */ -- 2.20.1