diff --git a/bgpd/rfapi/rfapi_ap.c b/bgpd/rfapi/rfapi_ap.c
index c5fda15d33..abb18aeb2c 100644
--- a/bgpd/rfapi/rfapi_ap.c
+++ b/bgpd/rfapi/rfapi_ap.c
@@ -81,10 +81,10 @@
  * is used to spread out the sort for adbs with the same lifetime
  * and thereby make the skip list operations more efficient.
  */
-static int sl_adb_lifetime_cmp(void *adb1, void *adb2)
+static int sl_adb_lifetime_cmp(const void *adb1, const void *adb2)
 {
-	struct rfapi_adb *a1 = adb1;
-	struct rfapi_adb *a2 = adb2;
+	const struct rfapi_adb *a1 = adb1;
+	const struct rfapi_adb *a2 = adb2;
 
 	if (a1->lifetime < a2->lifetime)
 		return -1;
diff --git a/bgpd/rfapi/rfapi_import.c b/bgpd/rfapi/rfapi_import.c
index 5cb4fd5a10..6c50092e6a 100644
--- a/bgpd/rfapi/rfapi_import.c
+++ b/bgpd/rfapi/rfapi_import.c
@@ -2006,10 +2006,10 @@ static void rfapiBgpInfoDetach(struct agg_node *rn, struct bgp_path_info *bpi)
 /*
  * For L3-indexed import tables
  */
-static int rfapi_bi_peer_rd_cmp(void *b1, void *b2)
+static int rfapi_bi_peer_rd_cmp(const void *b1, const void *b2)
 {
-	struct bgp_path_info *bpi1 = b1;
-	struct bgp_path_info *bpi2 = b2;
+	const struct bgp_path_info *bpi1 = b1;
+	const struct bgp_path_info *bpi2 = b2;
 
 	/*
 	 * Compare peers
@@ -2022,8 +2022,9 @@ static int rfapi_bi_peer_rd_cmp(void *b1, void *b2)
 	/*
 	 * compare RDs
 	 */
-	return vnc_prefix_cmp((struct prefix *)&bpi1->extra->vnc.import.rd,
-			      (struct prefix *)&bpi2->extra->vnc.import.rd);
+	return vnc_prefix_cmp(
+		(const struct prefix *)&bpi1->extra->vnc.import.rd,
+		(const struct prefix *)&bpi2->extra->vnc.import.rd);
 }
 
 /*
@@ -2031,10 +2032,10 @@ static int rfapi_bi_peer_rd_cmp(void *b1, void *b2)
  * The BPIs in these tables should ALWAYS have an aux_prefix set because
  * they arrive via IPv4 or IPv6 advertisements.
  */
-static int rfapi_bi_peer_rd_aux_cmp(void *b1, void *b2)
+static int rfapi_bi_peer_rd_aux_cmp(const void *b1, const void *b2)
 {
-	struct bgp_path_info *bpi1 = b1;
-	struct bgp_path_info *bpi2 = b2;
+	const struct bgp_path_info *bpi1 = b1;
+	const struct bgp_path_info *bpi2 = b2;
 	int rc;
 
 	/*
diff --git a/bgpd/rfapi/rfapi_monitor.c b/bgpd/rfapi/rfapi_monitor.c
index dc1f7e0fbb..74094efdf3 100644
--- a/bgpd/rfapi/rfapi_monitor.c
+++ b/bgpd/rfapi/rfapi_monitor.c
@@ -1103,10 +1103,10 @@ static void rfapiMonitorEthTimerRestart(struct rfapi_monitor_eth *m)
 			 m->rfd->response_lifetime, &m->timer);
 }
 
-static int mon_eth_cmp(void *a, void *b)
+static int mon_eth_cmp(const void *a, const void *b)
 {
-	struct rfapi_monitor_eth *m1;
-	struct rfapi_monitor_eth *m2;
+	const struct rfapi_monitor_eth *m1;
+	const struct rfapi_monitor_eth *m2;
 
 	int i;
 
diff --git a/bgpd/rfapi/rfapi_nve_addr.c b/bgpd/rfapi/rfapi_nve_addr.c
index ee54d88c3f..b8193f1431 100644
--- a/bgpd/rfapi/rfapi_nve_addr.c
+++ b/bgpd/rfapi/rfapi_nve_addr.c
@@ -58,10 +58,10 @@ static void logdifferent(const char *tag, struct rfapi_nve_addr *a,
 #endif
 
 
-int rfapi_nve_addr_cmp(void *k1, void *k2)
+int rfapi_nve_addr_cmp(const void *k1, const void *k2)
 {
-	struct rfapi_nve_addr *a = (struct rfapi_nve_addr *)k1;
-	struct rfapi_nve_addr *b = (struct rfapi_nve_addr *)k2;
+	const struct rfapi_nve_addr *a = (struct rfapi_nve_addr *)k1;
+	const struct rfapi_nve_addr *b = (struct rfapi_nve_addr *)k2;
 	int ret = 0;
 
 	if (!a || !b) {
diff --git a/bgpd/rfapi/rfapi_nve_addr.h b/bgpd/rfapi/rfapi_nve_addr.h
index 2d54d4a3cc..7bcb3cab69 100644
--- a/bgpd/rfapi/rfapi_nve_addr.h
+++ b/bgpd/rfapi/rfapi_nve_addr.h
@@ -30,7 +30,7 @@ struct rfapi_nve_addr {
 };
 
 
-extern int rfapi_nve_addr_cmp(void *k1, void *k2);
+extern int rfapi_nve_addr_cmp(const void *k1, const void *k2);
 
 extern void rfapiNveAddr2Str(struct rfapi_nve_addr *na, char *buf, int bufsize);
 
diff --git a/bgpd/rfapi/rfapi_rib.c b/bgpd/rfapi/rfapi_rib.c
index 3d4bdef75a..141fb03d36 100644
--- a/bgpd/rfapi/rfapi_rib.c
+++ b/bgpd/rfapi/rfapi_rib.c
@@ -388,10 +388,10 @@ extern void rfapi_rib_key_init(struct prefix *prefix, /* may be NULL */
 /*
  * Compares two <struct rfapi_rib_key>s
  */
-int rfapi_rib_key_cmp(void *k1, void *k2)
+int rfapi_rib_key_cmp(const void *k1, const void *k2)
 {
-	struct rfapi_rib_key *a = (struct rfapi_rib_key *)k1;
-	struct rfapi_rib_key *b = (struct rfapi_rib_key *)k2;
+	const struct rfapi_rib_key *a = (struct rfapi_rib_key *)k1;
+	const struct rfapi_rib_key *b = (struct rfapi_rib_key *)k2;
 	int ret;
 
 	if (!a || !b)
diff --git a/bgpd/rfapi/rfapi_rib.h b/bgpd/rfapi/rfapi_rib.h
index 38a6df9fbf..3ad021b4f4 100644
--- a/bgpd/rfapi/rfapi_rib.h
+++ b/bgpd/rfapi/rfapi_rib.h
@@ -147,7 +147,7 @@ extern void rfapi_rib_key_init(struct prefix *prefix, /* may be NULL */
 			       struct prefix *aux,    /* may be NULL */
 			       struct rfapi_rib_key *rk);
 
-extern int rfapi_rib_key_cmp(void *k1, void *k2);
+extern int rfapi_rib_key_cmp(const void *k1, const void *k2);
 
 extern void rfapiAdbFree(struct rfapi_adb *adb);
 
diff --git a/bgpd/rfapi/rfapi_vty.c b/bgpd/rfapi/rfapi_vty.c
index b18c9e07b5..aa9c216959 100644
--- a/bgpd/rfapi/rfapi_vty.c
+++ b/bgpd/rfapi/rfapi_vty.c
@@ -2754,10 +2754,10 @@ static void nve_addr_free(void *hap)
 	XFREE(MTYPE_RFAPI_NVE_ADDR, hap);
 }
 
-static int nve_addr_cmp(void *k1, void *k2)
+static int nve_addr_cmp(const void *k1, const void *k2)
 {
-	struct nve_addr *a = (struct nve_addr *)k1;
-	struct nve_addr *b = (struct nve_addr *)k2;
+	const struct nve_addr *a = (struct nve_addr *)k1;
+	const struct nve_addr *b = (struct nve_addr *)k2;
 	int ret = 0;
 
 	if (!a || !b) {
diff --git a/bgpd/rfapi/vnc_import_bgp.c b/bgpd/rfapi/vnc_import_bgp.c
index ba6ef14257..d5e509d30d 100644
--- a/bgpd/rfapi/vnc_import_bgp.c
+++ b/bgpd/rfapi/vnc_import_bgp.c
@@ -128,14 +128,14 @@ struct prefix_bag {
 static const uint8_t maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0,
 				  0xf8, 0xfc, 0xfe, 0xff};
 
-int vnc_prefix_cmp(void *pfx1, void *pfx2)
+int vnc_prefix_cmp(const void *pfx1, const void *pfx2)
 {
 	int offset;
 	int shift;
 	uint8_t mask;
 
-	struct prefix *p1 = pfx1;
-	struct prefix *p2 = pfx2;
+	const struct prefix *p1 = pfx1;
+	const struct prefix *p2 = pfx2;
 
 	if (p1->family < p2->family)
 		return -1;
diff --git a/bgpd/rfapi/vnc_import_bgp.h b/bgpd/rfapi/vnc_import_bgp.h
index 3db6f4010a..ca64e6eacc 100644
--- a/bgpd/rfapi/vnc_import_bgp.h
+++ b/bgpd/rfapi/vnc_import_bgp.h
@@ -32,7 +32,7 @@
 
 extern uint32_t calc_local_pref(struct attr *attr, struct peer *peer);
 
-extern int vnc_prefix_cmp(void *pfx1, void *pfx2);
+extern int vnc_prefix_cmp(const void *pfx1, const void *pfx2);
 
 extern void vnc_import_bgp_add_route(struct bgp *bgp, struct prefix *prefix,
 				     struct bgp_path_info *info);
diff --git a/isisd/fabricd.c b/isisd/fabricd.c
index b9c27d51bd..28cc65380f 100644
--- a/isisd/fabricd.c
+++ b/isisd/fabricd.c
@@ -122,9 +122,9 @@ static bool neighbor_entry_hash_cmp(const void *a, const void *b)
 	return memcmp(na->id, nb->id, sizeof(na->id)) == 0;
 }
 
-static int neighbor_entry_list_cmp(void *a, void *b)
+static int neighbor_entry_list_cmp(const void *a, const void *b)
 {
-	struct neighbor_entry *na = a, *nb = b;
+	const struct neighbor_entry *na = a, *nb = b;
 
 	return -memcmp(na->id, nb->id, sizeof(na->id));
 }
diff --git a/isisd/isis_spf_private.h b/isisd/isis_spf_private.h
index a8185a8be0..05aae14b94 100644
--- a/isisd/isis_spf_private.h
+++ b/isisd/isis_spf_private.h
@@ -117,11 +117,11 @@ static bool isis_vertex_queue_hash_cmp(const void *a, const void *b)
  * Compares vertizes for sorting in the TENT list. Returns true
  * if candidate should be considered before current, false otherwise.
  */
-__attribute__((__unused__))
-static int isis_vertex_queue_tent_cmp(void *a, void *b)
+__attribute__((__unused__)) static int isis_vertex_queue_tent_cmp(const void *a,
+								  const void *b)
 {
-	struct isis_vertex *va = a;
-	struct isis_vertex *vb = b;
+	const struct isis_vertex *va = a;
+	const struct isis_vertex *vb = b;
 
 	if (va->d_N < vb->d_N)
 		return -1;
diff --git a/lib/skiplist.c b/lib/skiplist.c
index d955c6eb9e..fa25770efa 100644
--- a/lib/skiplist.c
+++ b/lib/skiplist.c
@@ -112,7 +112,7 @@ static int randomLevel(void)
 	return level;
 }
 
-static int default_cmp(void *key1, void *key2)
+static int default_cmp(const void *key1, const void *key2)
 {
 	if (key1 < key2)
 		return -1;
@@ -126,7 +126,8 @@ unsigned int skiplist_count(struct skiplist *l)
 	return l->count;
 }
 
-struct skiplist *skiplist_new(int flags, int (*cmp)(void *key1, void *key2),
+struct skiplist *skiplist_new(int flags,
+			      int (*cmp)(const void *key1, const void *key2),
 			      void (*del)(void *val))
 {
 	struct skiplist *new;
@@ -329,8 +330,8 @@ int skiplist_delete(register struct skiplist *l, register void *key,
  * Also set a cursor for use with skiplist_next_value.
  */
 int skiplist_first_value(register struct skiplist *l, /* in */
-			 register void *key,	  /* in */
-			 void **valuePointer,	 /* out */
+			 register const void *key,    /* in */
+			 void **valuePointer,	      /* out */
 			 void **cursor)		      /* out */
 {
 	register int k;
@@ -374,7 +375,7 @@ int skiplist_search(register struct skiplist *l, register void *key,
  * last element with the given key, -1 is returned.
  */
 int skiplist_next_value(register struct skiplist *l, /* in */
-			register void *key,	  /* in */
+			register const void *key,	  /* in */
 			void **valuePointer,	 /* in/out */
 			void **cursor)		     /* in/out */
 {
diff --git a/lib/skiplist.h b/lib/skiplist.h
index 2ab37331c9..a106a455d6 100644
--- a/lib/skiplist.h
+++ b/lib/skiplist.h
@@ -68,7 +68,7 @@ struct skiplist {
 	 * Returns -1 if val1 < val2, 0 if equal?, 1 if val1 > val2.
 	 * Used as definition of sorted for listnode_add_sort
 	 */
-	int (*cmp)(void *val1, void *val2);
+	int (*cmp)(const void *val1, const void *val2);
 
 	/* callback to free user-owned data when listnode is deleted. supplying
 	 * this callback is very much encouraged!
@@ -81,8 +81,9 @@ struct skiplist {
 extern struct skiplist *
 skiplist_new(/* encouraged: set list.del callback on new lists */
 	     int flags,
-	     int (*cmp)(void *key1, void *key2), /* NULL => default cmp */
-	     void (*del)(void *val));		 /* NULL => no auto val free */
+	     int (*cmp)(const void *key1,
+			const void *key2), /* NULL => default cmp */
+	     void (*del)(void *val));	   /* NULL => no auto val free */
 
 extern void skiplist_free(struct skiplist *);
 
@@ -96,12 +97,12 @@ extern int skiplist_search(register struct skiplist *l, register void *key,
 			   void **valuePointer);
 
 extern int skiplist_first_value(register struct skiplist *l, /* in */
-				register void *key,	  /* in */
-				void **valuePointer,	 /* in/out */
+				register const void *key,    /* in */
+				void **valuePointer,	     /* in/out */
 				void **cursor);		     /* out */
 
 extern int skiplist_next_value(register struct skiplist *l, /* in */
-			       register void *key,	  /* in */
+			       register const void *key,	  /* in */
 			       void **valuePointer,	 /* in/out */
 			       void **cursor);		    /* in/out */