lib, bgpd: Enhance `srv6_locator_chunk_free()` API

A programmer can use the `srv6_locator_chunk_free()` function to free
the memory allocated for a `struct srv6_locator_chunk`.

The programmer invokes `srv6_locator_chunk_free()` by passing a single
pointer to the `struct srv6_locator_chunk` to be freed.
`srv6_locator_chunk_free()` uses `XFREE()` to free the memory.
It is the responsibility of the programmer to set the
`struct srv6_locator_chunk` pointer to NULL after freeing memory with
`srv6_locator_chunk_free()`.

This commit modifies the `srv6_locator_chunk_free()` function to take a
double pointer instead of a single pointer. In this way, setting the
`struct srv6_locator_chunk` pointer to NULL is no longer the
programmer's responsibility but is the responsibility of
`srv6_locator_chunk_free()`. This prevents programmers from making
mistakes such as forgetting to set the pointer to NULL after invoking
`srv6_locator_chunk_free()`.

Signed-off-by: Carmine Scarpitta <carmine.scarpitta@uniroma2.it>

5 files changed, 24 insertions, 17 deletions

diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index a68167977d..ad4221d134 100644
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -779,7 +779,7 @@ void ensure_vrf_tovpn_sid_per_af(struct bgp *bgp_vpn, struct bgp *bgp_vrf,
 			zlog_debug(
 				"%s: not allocated new sid for vrf %s: afi %s",
 				__func__, bgp_vrf->name_pretty, afi2str(afi));
-		srv6_locator_chunk_free(tovpn_sid_locator);
+		srv6_locator_chunk_free(&tovpn_sid_locator);
 		XFREE(MTYPE_BGP_SRV6_SID, tovpn_sid);
 		return;
 	}
@@ -844,7 +844,7 @@ void ensure_vrf_tovpn_sid_per_vrf(struct bgp *bgp_vpn, struct bgp *bgp_vrf)
 		if (debug)
 			zlog_debug("%s: not allocated new sid for vrf %s",
 				   __func__, bgp_vrf->name_pretty);
-		srv6_locator_chunk_free(tovpn_sid_locator);
+		srv6_locator_chunk_free(&tovpn_sid_locator);
 		XFREE(MTYPE_BGP_SRV6_SID, tovpn_sid);
 		return;
 	}
@@ -891,7 +891,7 @@ void delete_vrf_tovpn_sid_per_af(struct bgp *bgp_vpn, struct bgp *bgp_vrf,
 	if (tovpn_sid_index != 0 || tovpn_sid_auto)
 		return;
 
-	srv6_locator_chunk_free(bgp_vrf->vpn_policy[afi].tovpn_sid_locator);
+	srv6_locator_chunk_free(&bgp_vrf->vpn_policy[afi].tovpn_sid_locator);
 	bgp_vrf->vpn_policy[afi].tovpn_sid_locator = NULL;
 
 	if (bgp_vrf->vpn_policy[afi].tovpn_sid) {
@@ -919,7 +919,7 @@ void delete_vrf_tovpn_sid_per_vrf(struct bgp *bgp_vpn, struct bgp *bgp_vrf)
 	if (tovpn_sid_index != 0 || tovpn_sid_auto)
 		return;
 
-	srv6_locator_chunk_free(bgp_vrf->tovpn_sid_locator);
+	srv6_locator_chunk_free(&bgp_vrf->tovpn_sid_locator);
 	bgp_vrf->tovpn_sid_locator = NULL;
 
 	if (bgp_vrf->tovpn_sid) {
diff --git a/bgpd/bgp_vty.c b/bgpd/bgp_vty.c
index f380460a95..09f4fada80 100644
--- a/bgpd/bgp_vty.c
+++ b/bgpd/bgp_vty.c
@@ -310,7 +310,7 @@ static int bgp_srv6_locator_unset(struct bgp *bgp)
 	/* refresh chunks */
 	for (ALL_LIST_ELEMENTS(bgp->srv6_locator_chunks, node, nnode, chunk)) {
 		listnode_delete(bgp->srv6_locator_chunks, chunk);
-		srv6_locator_chunk_free(chunk);
+		srv6_locator_chunk_free(&chunk);
 	}
 
 	/* refresh functions */
@@ -348,7 +348,8 @@ static int bgp_srv6_locator_unset(struct bgp *bgp)
 		tovpn_sid_locator =
 			bgp_vrf->vpn_policy[AFI_IP].tovpn_sid_locator;
 		if (tovpn_sid_locator) {
-			srv6_locator_chunk_free(tovpn_sid_locator);
+			srv6_locator_chunk_free(
+				&bgp_vrf->vpn_policy[AFI_IP].tovpn_sid_locator);
 			bgp_vrf->vpn_policy[AFI_IP].tovpn_sid_locator = NULL;
 		}
 
@@ -356,12 +357,13 @@ static int bgp_srv6_locator_unset(struct bgp *bgp)
 		tovpn_sid_locator =
 			bgp_vrf->vpn_policy[AFI_IP6].tovpn_sid_locator;
 		if (tovpn_sid_locator) {
-			srv6_locator_chunk_free(tovpn_sid_locator);
+			srv6_locator_chunk_free(&bgp_vrf->vpn_policy[AFI_IP6]
+							 .tovpn_sid_locator);
 			bgp_vrf->vpn_policy[AFI_IP6].tovpn_sid_locator = NULL;
 		}
 
 		/* refresh per-vrf tovpn_sid_locator */
-		srv6_locator_chunk_free(bgp_vrf->tovpn_sid_locator);
+		srv6_locator_chunk_free(&bgp_vrf->tovpn_sid_locator);
 	}
 
 	/* clear locator name */
diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
index f7dda74cce..f6c0863241 100644
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -3219,13 +3219,13 @@ static int bgp_zebra_process_srv6_locator_chunk(ZAPI_CALLBACK_ARGS)
 	if (strcmp(bgp->srv6_locator_name, chunk->locator_name) != 0) {
 		zlog_err("%s: Locator name unmatch %s:%s", __func__,
 			 bgp->srv6_locator_name, chunk->locator_name);
-		srv6_locator_chunk_free(chunk);
+		srv6_locator_chunk_free(&chunk);
 		return 0;
 	}
 
 	for (ALL_LIST_ELEMENTS_RO(bgp->srv6_locator_chunks, node, c)) {
 		if (!prefix_cmp(&c->prefix, &chunk->prefix)) {
-			srv6_locator_chunk_free(chunk);
+			srv6_locator_chunk_free(&chunk);
 			return 0;
 		}
 	}
@@ -3272,7 +3272,7 @@ static int bgp_zebra_process_srv6_locator_delete(ZAPI_CALLBACK_ARGS)
 		if (prefix_match((struct prefix *)&loc.prefix,
 				 (struct prefix *)&chunk->prefix)) {
 			listnode_delete(bgp->srv6_locator_chunks, chunk);
-			srv6_locator_chunk_free(chunk);
+			srv6_locator_chunk_free(&chunk);
 		}
 
 	// refresh functions
@@ -3344,7 +3344,9 @@ static int bgp_zebra_process_srv6_locator_delete(ZAPI_CALLBACK_ARGS)
 			tmp_prefi.prefix = tovpn_sid_locator->prefix.prefix;
 			if (prefix_match((struct prefix *)&loc.prefix,
 					 (struct prefix *)&tmp_prefi)) {
-				srv6_locator_chunk_free(tovpn_sid_locator);
+				srv6_locator_chunk_free(
+					&bgp_vrf->vpn_policy[AFI_IP]
+						 .tovpn_sid_locator);
 				bgp_vrf->vpn_policy[AFI_IP].tovpn_sid_locator =
 					NULL;
 			}
@@ -3359,7 +3361,9 @@ static int bgp_zebra_process_srv6_locator_delete(ZAPI_CALLBACK_ARGS)
 			tmp_prefi.prefix = tovpn_sid_locator->prefix.prefix;
 			if (prefix_match((struct prefix *)&loc.prefix,
 					 (struct prefix *)&tmp_prefi)) {
-				srv6_locator_chunk_free(tovpn_sid_locator);
+				srv6_locator_chunk_free(
+					&bgp_vrf->vpn_policy[AFI_IP6]
+						 .tovpn_sid_locator);
 				bgp_vrf->vpn_policy[AFI_IP6].tovpn_sid_locator =
 					NULL;
 			}
@@ -3373,7 +3377,8 @@ static int bgp_zebra_process_srv6_locator_delete(ZAPI_CALLBACK_ARGS)
 			tmp_prefi.prefix = tovpn_sid_locator->prefix.prefix;
 			if (prefix_match((struct prefix *)&loc.prefix,
 					 (struct prefix *)&tmp_prefi))
-				srv6_locator_chunk_free(tovpn_sid_locator);
+				srv6_locator_chunk_free(
+					&bgp_vrf->tovpn_sid_locator);
 		}
 	}
 
diff --git a/lib/srv6.c b/lib/srv6.c
index 306d92ae30..a8ec6f2b71 100644
--- a/lib/srv6.c
+++ b/lib/srv6.c
@@ -157,9 +157,9 @@ void srv6_locator_free(struct srv6_locator *locator)
 	}
 }
 
-void srv6_locator_chunk_free(struct srv6_locator_chunk *chunk)
+void srv6_locator_chunk_free(struct srv6_locator_chunk **chunk)
 {
-	XFREE(MTYPE_SRV6_LOCATOR_CHUNK, chunk);
+	XFREE(MTYPE_SRV6_LOCATOR_CHUNK, *chunk);
 }
 
 json_object *srv6_locator_chunk_json(const struct srv6_locator_chunk *chunk)
diff --git a/lib/srv6.h b/lib/srv6.h
index 6e0c3ce99d..18d5bdebc2 100644
--- a/lib/srv6.h
+++ b/lib/srv6.h
@@ -187,7 +187,7 @@ int snprintf_seg6_segs(char *str,
 extern struct srv6_locator *srv6_locator_alloc(const char *name);
 extern struct srv6_locator_chunk *srv6_locator_chunk_alloc(void);
 extern void srv6_locator_free(struct srv6_locator *locator);
-extern void srv6_locator_chunk_free(struct srv6_locator_chunk *chunk);
+extern void srv6_locator_chunk_free(struct srv6_locator_chunk **chunk);
 json_object *srv6_locator_chunk_json(const struct srv6_locator_chunk *chunk);
 json_object *srv6_locator_json(const struct srv6_locator *loc);
 json_object *srv6_locator_detailed_json(const struct srv6_locator *loc);