diff options
Diffstat (limited to 'net/ipv4/gre.c')
| -rw-r--r-- | net/ipv4/gre.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c index 8b9a373890ab..1cbc46536d1f 100644 --- a/net/ipv4/gre.c +++ b/net/ipv4/gre.c @@ -61,6 +61,38 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version) } EXPORT_SYMBOL_GPL(gre_del_protocol); +void gre_build_header(struct sk_buff *skb, const struct tnl_ptk_info *tpi, + int hdr_len) +{ + struct gre_base_hdr *greh; + + skb_push(skb, hdr_len); + + greh = (struct gre_base_hdr *)skb->data; + greh->flags = tnl_flags_to_gre_flags(tpi->flags); + greh->protocol = tpi->proto; + + if (tpi->flags&(TUNNEL_KEY|TUNNEL_CSUM|TUNNEL_SEQ)) { + __be32 *ptr = (__be32 *)(((u8 *)greh) + hdr_len - 4); + + if (tpi->flags&TUNNEL_SEQ) { + *ptr = tpi->seq; + ptr--; + } + if (tpi->flags&TUNNEL_KEY) { + *ptr = tpi->key; + ptr--; + } + if (tpi->flags&TUNNEL_CSUM && + !(skb_shinfo(skb)->gso_type & SKB_GSO_GRE)) { + *ptr = 0; + *(__sum16 *)ptr = csum_fold(skb_checksum(skb, 0, + skb->len, 0)); + } + } +} +EXPORT_SYMBOL_GPL(gre_build_header); + static __sum16 check_checksum(struct sk_buff *skb) { __sum16 csum = 0; |