net: pim: add common pimhdr struct and helpers

Add the common pimhdr structure and helpers to access it, also cleanup the
format of the header file.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/pim.h b/include/linux/pim.h
index e1d756f..354235a 100644 (file)
--- a/include/linux/pim.h
+++ b/include/linux/pim.h
@@ -1,6 +1,7 @@
 #ifndef __LINUX_PIM_H
 #define __LINUX_PIM_H
 
+#include <linux/skbuff.h>
 #include <asm/byteorder.h>
 
 /* Message types - V1 */
@@ -13,20 +14,47 @@
 
 #define PIM_NULL_REGISTER      cpu_to_be32(0x40000000)
 
-static inline bool ipmr_pimsm_enabled(void)
-{
-       return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
-}
+/* RFC7761, sec 4.9:
+ * The PIM header common to all PIM messages is:
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |PIM Ver| Type  |   Reserved    |           Checksum            |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct pimhdr {
+       __u8    type;
+       __u8    reserved;
+       __be16  csum;
+};
 
 /* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
-struct pimreghdr
-{
+struct pimreghdr {
        __u8    type;
        __u8    reserved;
        __be16  csum;
        __be32  flags;
 };
 
-struct sk_buff;
-extern int pim_rcv_v1(struct sk_buff *);
+int pim_rcv_v1(struct sk_buff *skb);
+
+static inline bool ipmr_pimsm_enabled(void)
+{
+       return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
+}
+
+static inline struct pimhdr *pim_hdr(const struct sk_buff *skb)
+{
+       return (struct pimhdr *)skb_transport_header(skb);
+}
+
+static inline u8 pim_hdr_version(const struct pimhdr *pimhdr)
+{
+       return pimhdr->type >> 4;
+}
+
+static inline u8 pim_hdr_type(const struct pimhdr *pimhdr)
+{
+       return pimhdr->type & 0xf;
+}
 #endif