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authorTom Herbert <tom@herbertland.com>2016-04-30 03:12:16 +0300
committerDavid S. Miller <davem@davemloft.net>2016-05-03 02:23:31 +0300
commit95f5c64c3c13a609e137d35c4b452519e0b954df (patch)
treea01c464cb5ff29e77e546881b69f8f541bf22861 /net/ipv4/gre_demux.c
parent0d3c703a9d1723c7707e0680019ac8ff5922db42 (diff)
downloadlinux-95f5c64c3c13a609e137d35c4b452519e0b954df.tar.xz
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 <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/gre_demux.c')
-rw-r--r--net/ipv4/gre_demux.c64
1 files changed, 64 insertions, 0 deletions
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;