From 95f5c64c3c13a609e137d35c4b452519e0b954df Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 29 Apr 2016 17:12:16 -0700 Subject: gre: Move utility functions to common headers Several of the GRE functions defined in net/ipv4/ip_gre.c are usable for IPv6 GRE implementation (that is they are protocol agnostic). These include: - GRE flag handling functions are move to gre.h - GRE build_header is moved to gre.h and renamed gre_build_header - parse_gre_header is moved to gre_demux.c and renamed gre_parse_header - iptunnel_pull_header is taken out of gre_parse_header. This is now done by caller. The header length is returned from gre_parse_header in an int* argument. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/gre_demux.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) (limited to 'net/ipv4/gre_demux.c') diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c index d9c552a721fc..371674801e84 100644 --- a/net/ipv4/gre_demux.c +++ b/net/ipv4/gre_demux.c @@ -60,6 +60,70 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version) } EXPORT_SYMBOL_GPL(gre_del_protocol); +int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi, + bool *csum_err, int *ret_hdr_len) +{ + const struct gre_base_hdr *greh; + __be32 *options; + int hdr_len; + + if (unlikely(!pskb_may_pull(skb, sizeof(struct gre_base_hdr)))) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING))) + return -EINVAL; + + tpi->flags = gre_flags_to_tnl_flags(greh->flags); + hdr_len = gre_calc_hlen(tpi->flags); + + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + + greh = (struct gre_base_hdr *)skb_transport_header(skb); + tpi->proto = greh->protocol; + + options = (__be32 *)(greh + 1); + if (greh->flags & GRE_CSUM) { + if (skb_checksum_simple_validate(skb)) { + *csum_err = true; + return -EINVAL; + } + + skb_checksum_try_convert(skb, IPPROTO_GRE, 0, + null_compute_pseudo); + options++; + } + + if (greh->flags & GRE_KEY) { + tpi->key = *options; + options++; + } else { + tpi->key = 0; + } + if (unlikely(greh->flags & GRE_SEQ)) { + tpi->seq = *options; + options++; + } else { + tpi->seq = 0; + } + /* WCCP version 1 and 2 protocol decoding. + * - Change protocol to IP + * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header + */ + if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) { + tpi->proto = htons(ETH_P_IP); + if ((*(u8 *)options & 0xF0) != 0x40) { + hdr_len += 4; + if (!pskb_may_pull(skb, hdr_len)) + return -EINVAL; + } + } + *ret_hdr_len = hdr_len; + return 0; +} +EXPORT_SYMBOL(gre_parse_header); + static int gre_rcv(struct sk_buff *skb) { const struct gre_protocol *proto; -- cgit v1.2.3