[nh-encap] Extract functions to directly manipulate struct rtnl_nh_encap

cpaasch-oai · cpaasch-oai · commit f1263ca0bd4f · 2025-08-06T16:23:23.000-07:00
The goal is to have struct rtnl_nh_encap be used for the route's nexthop
(In struct rtnl_nexthop) but also directly in an IP nexthop (struct
rtnl_nh).

So, let's extract some functions to manipulate struct rtnl_nh_encap
directly. Ideally, even for the route's nexthop we will use those to
manipulate the encap.

Ideally we stop using rtnl_route_nh_encap_mpls (and friends) and rather
configure an encapsulation on a route's nexthop by using:

nh = rtnl_nh_encap_alloc()
rtnl_nh_encap_mpls(nh, ...)
rtnl_route_nh_set_encap(rtnh, nh)

Add tests for these new functions and drop the tests for the deprecated
ones.

Signed-off-by: Christoph Paasch &lt;cpaasch@openai.com&gt;
diff --git a/include/netlink/route/nexthop.h b/include/netlink/route/nexthop.h
@@ -14,6 +14,7 @@ extern "C" {
 #endif
 
 struct rtnl_nexthop;
+struct rtnl_nh_encap;
 
 enum {
 	NH_DUMP_FROM_ONELINE = -2,
@@ -50,16 +51,32 @@ extern int rtnl_route_nh_set_newdst(struct rtnl_nexthop *, struct nl_addr *);
 extern struct nl_addr *rtnl_route_nh_get_newdst(struct rtnl_nexthop *);
 extern int rtnl_route_nh_set_via(struct rtnl_nexthop *, struct nl_addr *);
 extern struct nl_addr *rtnl_route_nh_get_via(struct rtnl_nexthop *);
+extern int rtnl_route_nh_set_encap(struct rtnl_nexthop *,
+				   struct rtnl_nh_encap *);
+extern struct rtnl_nh_encap *rtnl_route_nh_get_encap(struct rtnl_nexthop *);
 extern char *rtnl_route_nh_flags2str(int, char *, size_t);
 extern int rtnl_route_nh_str2flags(const char *);
 
 /*
  * nexthop encapsulations
  */
+extern struct rtnl_nh_encap *rtnl_nh_encap_alloc(void);
+extern void rtnl_nh_encap_free(struct rtnl_nh_encap *nh_encap);
+
+extern int rtnl_nh_encap_mpls(struct rtnl_nh_encap *nh_encap,
+			      struct nl_addr *dst, uint8_t ttl);
+struct nl_addr *rtnl_nh_get_encap_mpls_dst(struct rtnl_nh_encap *);
+extern uint8_t rtnl_nh_get_encap_mpls_ttl(struct rtnl_nh_encap *);
+
+/* Deprecated */
 extern int rtnl_route_nh_encap_mpls(struct rtnl_nexthop *nh,
-				    struct nl_addr *addr, uint8_t ttl);
-extern struct nl_addr *rtnl_route_nh_get_encap_mpls_dst(struct rtnl_nexthop *);
-extern uint8_t rtnl_route_nh_get_encap_mpls_ttl(struct rtnl_nexthop *);
+				    struct nl_addr *addr, uint8_t ttl)
+	__attribute__((deprecated));
+extern struct nl_addr *rtnl_route_nh_get_encap_mpls_dst(struct rtnl_nexthop *)
+	__attribute__((deprecated));
+extern uint8_t rtnl_route_nh_get_encap_mpls_ttl(struct rtnl_nexthop *)
+	__attribute__((deprecated));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/route/nexthop-encap.h b/lib/route/nexthop-encap.h
@@ -18,8 +18,6 @@ struct rtnl_nh_encap;
 /*
  * generic nexthop encap
  */
-void nh_set_encap(struct rtnl_nexthop *nh, struct rtnl_nh_encap *rtnh_encap);
-
 int nh_encap_parse_msg(struct nlattr *encap, struct nlattr *encap_type,
 		       struct rtnl_nexthop *rtnh);
 int nh_encap_build_msg(struct nl_msg *msg, struct rtnl_nh_encap *rtnh_encap);
diff --git a/lib/route/nexthop.c b/lib/route/nexthop.c
@@ -98,12 +98,7 @@ void rtnl_route_nh_free(struct rtnl_nexthop *nh)
 	nl_addr_put(nh->rtnh_gateway);
 	nl_addr_put(nh->rtnh_newdst);
 	nl_addr_put(nh->rtnh_via);
-	if (nh->rtnh_encap) {
-		if (nh->rtnh_encap->ops && nh->rtnh_encap->ops->destructor)
-			nh->rtnh_encap->ops->destructor(nh->rtnh_encap->priv);
-		free(nh->rtnh_encap->priv);
-		free(nh->rtnh_encap);
-	}
+	rtnl_nh_encap_free(nh->rtnh_encap);
 	free(nh);
 }
 
@@ -260,24 +255,6 @@ void rtnl_route_nh_dump(struct rtnl_nexthop *nh, struct nl_dump_params *dp)
 	}
 }
 
-void nh_set_encap(struct rtnl_nexthop *nh, struct rtnl_nh_encap *rtnh_encap)
-{
-	if (nh->rtnh_encap) {
-		if (nh->rtnh_encap->ops && nh->rtnh_encap->ops->destructor)
-			nh->rtnh_encap->ops->destructor(nh->rtnh_encap->priv);
-		free(nh->rtnh_encap->priv);
-		free(nh->rtnh_encap);
-	}
-
-	if (rtnh_encap) {
-		nh->rtnh_encap = rtnh_encap;
-		nh->ce_mask |= NH_ATTR_ENCAP;
-	} else {
-		nh->rtnh_encap = NULL;
-		nh->ce_mask &= ~NH_ATTR_ENCAP;
-	}
-}
-
 /**
  * @name Attributes
  * @{
@@ -403,6 +380,30 @@ struct nl_addr *rtnl_route_nh_get_via(struct rtnl_nexthop *nh)
 	return nh->rtnh_via;
 }
 
+int rtnl_route_nh_set_encap(struct rtnl_nexthop *nh,
+			    struct rtnl_nh_encap *nh_encap)
+{
+	if (!nh)
+		return -NLE_INVAL;
+
+	if (nh->rtnh_encap) {
+		if (nh->rtnh_encap->ops && nh->rtnh_encap->ops->destructor)
+			nh->rtnh_encap->ops->destructor(nh->rtnh_encap->priv);
+		free(nh->rtnh_encap->priv);
+		free(nh->rtnh_encap);
+	}
+
+	if (nh_encap) {
+		nh->rtnh_encap = nh_encap;
+		nh->ce_mask |= NH_ATTR_ENCAP;
+	} else {
+		nh->rtnh_encap = NULL;
+		nh->ce_mask &= ~NH_ATTR_ENCAP;
+	}
+
+	return 0;
+}
+
 /** @} */
 
 /**
diff --git a/lib/route/nh.c b/lib/route/nh.c
@@ -13,6 +13,7 @@
 
 #include "nl-aux-route/nl-route.h"
 #include "nl-route.h"
+#include "nexthop-encap.h"
 #include "nl-priv-dynamic-core/nl-core.h"
 #include "nl-priv-dynamic-core/cache-api.h"
 
@@ -651,6 +652,33 @@ int rtnl_nh_add(struct nl_sock *sk, struct rtnl_nh *nh, int flags)
 	return wait_for_ack(sk);
 }
 
+struct rtnl_nh_encap *rtnl_nh_encap_alloc(void)
+{
+	return calloc(1, sizeof(struct rtnl_nh_encap));
+}
+
+void rtnl_nh_encap_free(struct rtnl_nh_encap *nh_encap)
+{
+	if (!nh_encap)
+		return;
+
+	if (nh_encap->ops && nh_encap->ops->destructor)
+		nh_encap->ops->destructor(nh_encap->priv);
+
+	free(nh_encap->priv);
+	free(nh_encap);
+}
+
+/*
+ * Retrieve the encapsulation associated with a nexthop if any.
+ */
+struct rtnl_nh_encap *rtnl_route_nh_get_encap(struct rtnl_nexthop *nh)
+{
+	if (!nh)
+		return NULL;
+
+	return nh->rtnh_encap;
+}
 static struct nla_policy nh_res_group_policy[NHA_RES_GROUP_MAX + 1] = {
 	[NHA_RES_GROUP_UNSPEC] = { .type = NLA_UNSPEC },
 	[NHA_RES_GROUP_BUCKETS] = { .type = NLA_U16 },
diff --git a/lib/route/nh_encap_mpls.c b/lib/route/nh_encap_mpls.c
@@ -55,6 +55,7 @@ static struct nla_policy mpls_encap_policy[MPLS_IPTUNNEL_MAX + 1] = {
 static int mpls_encap_parse_msg(struct nlattr *nla, struct rtnl_nexthop *nh)
 {
 	struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
+	struct rtnl_nh_encap *nh_encap;
 	struct nl_addr *labels;
 	uint8_t ttl = 0;
 	int err;
@@ -73,10 +74,30 @@ static int mpls_encap_parse_msg(struct nlattr *nla, struct rtnl_nexthop *nh)
 	if (tb[MPLS_IPTUNNEL_TTL])
 		ttl = nla_get_u8(tb[MPLS_IPTUNNEL_TTL]);
 
-	err = rtnl_route_nh_encap_mpls(nh, labels, ttl);
+	nh_encap = rtnl_nh_encap_alloc();
+	if (!nh_encap) {
+		err = -NLE_NOMEM;
+		goto err_out;
+	}
+
+	err = rtnl_nh_encap_mpls(nh_encap, labels, ttl);
+	if (err < 0) {
+		goto err_out;
+	}
+
+	err = rtnl_route_nh_set_encap(nh, nh_encap);
+	if (err < 0) {
+		goto err_out;
+	}
 
 	nl_addr_put(labels);
 
+	return 0;
+
+err_out:
+	rtnl_nh_encap_free(nh_encap);
+	nl_addr_put(labels);
+
 	return err;
 }
 
@@ -101,62 +122,84 @@ struct nh_encap_ops mpls_encap_ops = {
 	.destructor = mpls_encap_destructor,
 };
 
-int rtnl_route_nh_encap_mpls(struct rtnl_nexthop *nh, struct nl_addr *addr,
-			     uint8_t ttl)
+int rtnl_nh_encap_mpls(struct rtnl_nh_encap *nh_encap, struct nl_addr *dst,
+		       uint8_t ttl)
 {
 	struct mpls_iptunnel_encap *mpls_encap;
-	struct rtnl_nh_encap *rtnh_encap;
 
-	if (!addr)
+	if (!dst || !nh_encap)
 		return -NLE_INVAL;
 
-	rtnh_encap = calloc(1, sizeof(*rtnh_encap));
-	if (!rtnh_encap)
-		return -NLE_NOMEM;
-
 	mpls_encap = calloc(1, sizeof(*mpls_encap));
 	if (!mpls_encap) {
-		free(rtnh_encap);
 		return -NLE_NOMEM;
 	}
 
-	mpls_encap->dst = nl_addr_get(addr);
+	mpls_encap->dst = nl_addr_get(dst);
 	mpls_encap->ttl = ttl;
 
-	rtnh_encap->priv = mpls_encap;
-	rtnh_encap->ops = &mpls_encap_ops;
+	nh_encap->priv = mpls_encap;
+	nh_encap->ops = &mpls_encap_ops;
 
-	nh_set_encap(nh, rtnh_encap);
+	return 0;
+}
+
+int rtnl_route_nh_encap_mpls(struct rtnl_nexthop *nh, struct nl_addr *addr,
+			     uint8_t ttl)
+{
+	struct rtnl_nh_encap *rtnh_encap;
+	int ret;
+
+	rtnh_encap = rtnl_nh_encap_alloc();
+	if (!rtnh_encap) {
+		return -NLE_NOMEM;
+	}
+
+	ret = rtnl_nh_encap_mpls(rtnh_encap, addr, ttl);
+	if (ret < 0) {
+		rtnl_nh_encap_free(rtnh_encap);
+		return ret;
+	}
+
+	rtnl_route_nh_set_encap(nh, rtnh_encap);
 
 	return 0;
 }
 
-struct nl_addr *rtnl_route_nh_get_encap_mpls_dst(struct rtnl_nexthop *nh)
+struct nl_addr *rtnl_nh_get_encap_mpls_dst(struct rtnl_nh_encap *nh_encap)
 {
 	struct mpls_iptunnel_encap *mpls_encap;
 
-	if (!nh->rtnh_encap ||
-	    nh->rtnh_encap->ops->encap_type != LWTUNNEL_ENCAP_MPLS)
+	if (!nh_encap || nh_encap->ops->encap_type != LWTUNNEL_ENCAP_MPLS)
 		return NULL;
 
-	mpls_encap = (struct mpls_iptunnel_encap *)nh->rtnh_encap->priv;
+	mpls_encap = (struct mpls_iptunnel_encap *)nh_encap->priv;
 	if (!mpls_encap)
 		return NULL;
 
 	return mpls_encap->dst;
 }
 
-uint8_t rtnl_route_nh_get_encap_mpls_ttl(struct rtnl_nexthop *nh)
+struct nl_addr *rtnl_route_nh_get_encap_mpls_dst(struct rtnl_nexthop *nh)
+{
+	return rtnl_nh_get_encap_mpls_dst(nh->rtnh_encap);
+}
+
+uint8_t rtnl_nh_get_encap_mpls_ttl(struct rtnl_nh_encap *nh_encap)
 {
 	struct mpls_iptunnel_encap *mpls_encap;
 
-	if (!nh->rtnh_encap ||
-	    nh->rtnh_encap->ops->encap_type != LWTUNNEL_ENCAP_MPLS)
+	if (!nh_encap || nh_encap->ops->encap_type != LWTUNNEL_ENCAP_MPLS)
 		return 0;
 
-	mpls_encap = (struct mpls_iptunnel_encap *)nh->rtnh_encap->priv;
+	mpls_encap = (struct mpls_iptunnel_encap *)nh_encap->priv;
 	if (!mpls_encap)
 		return 0;
 
 	return mpls_encap->ttl;
 }
+
+uint8_t rtnl_route_nh_get_encap_mpls_ttl(struct rtnl_nexthop *nh)
+{
+	return rtnl_nh_get_encap_mpls_ttl(nh->rtnh_encap);
+}
diff --git a/libnl-route-3.sym b/libnl-route-3.sym
@@ -1371,6 +1371,11 @@ global:
 	rtnl_link_ip6_tnl_set_collect_metadata;
 	rtnl_link_is_bond;
 	rtnl_nh_add;
+	rtnl_nh_encap_alloc;
+	rtnl_nh_encap_free;
+	rtnl_nh_encap_mpls;
+	rtnl_nh_get_encap_mpls_dst;
+	rtnl_nh_get_encap_mpls_ttl;
 	rtnl_nh_get_family;
 	rtnl_nh_get_group_type;
 	rtnl_nh_get_oif;
@@ -1385,4 +1390,6 @@ global:
 	rtnl_nh_set_res_group_bucket_size;
 	rtnl_nh_set_res_group_idle_timer;
 	rtnl_nh_set_res_group_unbalanced_timer;
+	rtnl_route_nh_set_encap;
+	rtnl_route_nh_get_encap;
 } libnl_3_11;
diff --git a/tests/cksuite-route-nexthop.c b/tests/cksuite-route-nexthop.c
