pimd: Fix register receive pointer arithmetic

When receiving the register packet from another pim
neighbor at the RP, we were adding an incorrect
amount of bytes to find the start of the ip_hdr
of the encapsulated data.  This commit fixes
this issue.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

diff --git a/pimd/pim_register.c b/pimd/pim_register.c
index 75c1ba8717c94e2904af08e2d22c93f7a1812e3d..07f9652fe80758da394a4c3be6c53f2ab7a9f893 100644 (file)
--- a/pimd/pim_register.c
+++ b/pimd/pim_register.c
@@ -193,11 +193,18 @@ pim_register_recv (struct interface *ifp,
    * We need to know the inner source and dest
    */
   bits = (uint32_t *)tlv_buf;
-  ip_hdr = (struct ip *)(tlv_buf + PIM_MSG_REGISTER_LEN);
+
+  /*
+   * tlv_buf points to the start of the |B|N|... Reserved
+   * Line above.  So we need to add 4 bytes to get to the
+   * start of the actual Encapsulated data.
+   */
+#define PIM_MSG_REGISTER_BIT_RESERVED_LEN 4
+  ip_hdr = (struct ip *)(tlv_buf + PIM_MSG_REGISTER_BIT_RESERVED_LEN);
   //hlen = (ip_hdr->ip_hl << 2) | PIM_MSG_REGISTER_LEN;
   //msg = (uint8_t *)tlv_buf + hlen;
-  group = ip_hdr->ip_src;
-  source = ip_hdr->ip_dst;
+  source = ip_hdr->ip_src;
+  group = ip_hdr->ip_dst;
 
   if (I_am_RP (group) && (dest_addr.s_addr == ((RP (group))->rpf_addr.s_addr))) {
     sentRegisterStop = 0;