isisd: annotate some function arguments with const

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Acked-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/isisd/isis_pdu.c b/isisd/isis_pdu.c
index c50b53f..7408555 100644
--- a/isisd/isis_pdu.c
+++ b/isisd/isis_pdu.c
@@ -912,7 +912,7 @@
  * Process IS-IS LAN Level 1/2 Hello PDU
  */
 static int
-process_lan_hello (int level, struct isis_circuit *circuit, u_char * ssnpa)
+process_lan_hello (int level, struct isis_circuit *circuit, const u_char *ssnpa)
 {
   int retval = ISIS_OK;
   struct isis_lan_hello_hdr hdr;
@@ -1300,7 +1300,7 @@
  * Section 7.3.15.1 - Action on receipt of a link state PDU
  */
 static int
-process_lsp (int level, struct isis_circuit *circuit, u_char * ssnpa)
+process_lsp (int level, struct isis_circuit *circuit, const u_char *ssnpa)
 {
   struct isis_link_state_hdr *hdr;
   struct isis_adjacency *adj = NULL;
@@ -1649,7 +1649,7 @@
 
 static int
 process_snp (int snp_type, int level, struct isis_circuit *circuit,
-	     u_char * ssnpa)
+	     const u_char *ssnpa)
 {
   int retval = ISIS_OK;
   int cmp, own_lsp;
@@ -1945,7 +1945,7 @@
 }
 
 static int
-process_csnp (int level, struct isis_circuit *circuit, u_char * ssnpa)
+process_csnp (int level, struct isis_circuit *circuit, const u_char *ssnpa)
 {
   if (isis->debugs & DEBUG_SNP_PACKETS)
     {
@@ -1969,7 +1969,7 @@
 }
 
 static int
-process_psnp (int level, struct isis_circuit *circuit, u_char * ssnpa)
+process_psnp (int level, struct isis_circuit *circuit, const u_char *ssnpa)
 {
   if (isis->debugs & DEBUG_SNP_PACKETS)
     {