seg6: improve management of behavior attributes

[mirror_ubuntu-jammy-kernel.git] / net / ipv6 / seg6_local.c

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index eba23279912df7f326ff8c4b977158f3df9f55d7..aef39eab9be284c51ba11615ee4fabcf9733d866 100644 (file)
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -710,6 +710,11 @@ static int cmp_nla_srh(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
        return memcmp(a->srh, b->srh, len);
 }
 
+static void destroy_attr_srh(struct seg6_local_lwt *slwt)
+{
+       kfree(slwt->srh);
+}
+
 static int parse_nla_table(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 {
        slwt->table = nla_get_u32(attrs[SEG6_LOCAL_TABLE]);
@@ -901,16 +906,30 @@ static int cmp_nla_bpf(struct seg6_local_lwt *a, struct seg6_local_lwt *b)
        return strcmp(a->bpf.name, b->bpf.name);
 }
 
+static void destroy_attr_bpf(struct seg6_local_lwt *slwt)
+{
+       kfree(slwt->bpf.name);
+       if (slwt->bpf.prog)
+               bpf_prog_put(slwt->bpf.prog);
+}
+
 struct seg6_action_param {
        int (*parse)(struct nlattr **attrs, struct seg6_local_lwt *slwt);
        int (*put)(struct sk_buff *skb, struct seg6_local_lwt *slwt);
        int (*cmp)(struct seg6_local_lwt *a, struct seg6_local_lwt *b);
+
+       /* optional destroy() callback useful for releasing resources which
+        * have been previously acquired in the corresponding parse()
+        * function.
+        */
+       void (*destroy)(struct seg6_local_lwt *slwt);
 };
 
 static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
        [SEG6_LOCAL_SRH]        = { .parse = parse_nla_srh,
                                    .put = put_nla_srh,
-                                   .cmp = cmp_nla_srh },
+                                   .cmp = cmp_nla_srh,
+                                   .destroy = destroy_attr_srh },
 
        [SEG6_LOCAL_TABLE]      = { .parse = parse_nla_table,
                                    .put = put_nla_table,
@@ -934,10 +953,49 @@ static struct seg6_action_param seg6_action_params[SEG6_LOCAL_MAX + 1] = {
 
        [SEG6_LOCAL_BPF]        = { .parse = parse_nla_bpf,
                                    .put = put_nla_bpf,
-                                   .cmp = cmp_nla_bpf },
+                                   .cmp = cmp_nla_bpf,
+                                   .destroy = destroy_attr_bpf },
 
 };
 
+/* call the destroy() callback (if available) for each set attribute in
+ * @slwt, starting from the first attribute up to the @max_parsed (excluded)
+ * attribute.
+ */
+static void __destroy_attrs(int max_parsed, struct seg6_local_lwt *slwt)
+{
+       unsigned long attrs = slwt->desc->attrs;
+       struct seg6_action_param *param;
+       int i;
+
+       /* Every required seg6local attribute is identified by an ID which is
+        * encoded as a flag (i.e: 1 << ID) in the 'attrs' bitmask;
+        *
+        * We scan the 'attrs' bitmask, starting from the first attribute
+        * up to the @max_parsed (excluded) attribute.
+        * For each set attribute, we retrieve the corresponding destroy()
+        * callback. If the callback is not available, then we skip to the next
+        * attribute; otherwise, we call the destroy() callback.
+        */
+       for (i = 0; i < max_parsed; ++i) {
+               if (!(attrs & (1 << i)))
+                       continue;
+
+               param = &seg6_action_params[i];
+
+               if (param->destroy)
+                       param->destroy(slwt);
+       }
+}
+
+/* release all the resources that may have been acquired during parsing
+ * operations.
+ */
+static void destroy_attrs(struct seg6_local_lwt *slwt)
+{
+       __destroy_attrs(SEG6_LOCAL_MAX + 1, slwt);
+}
+
 static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 {
        struct seg6_action_param *param;
@@ -963,11 +1021,19 @@ static int parse_nla_action(struct nlattr **attrs, struct seg6_local_lwt *slwt)
 
                        err = param->parse(attrs, slwt);
                        if (err < 0)
-                               return err;
+                               goto parse_err;
                }
        }
 
        return 0;
+
+parse_err:
+       /* release any resource that may have been acquired during the i-1
+        * parse() operations.
+        */
+       __destroy_attrs(i, slwt);
+
+       return err;
 }
 
 static int seg6_local_build_state(struct net *net, struct nlattr *nla,
@@ -1012,7 +1078,6 @@ static int seg6_local_build_state(struct net *net, struct nlattr *nla,
        return 0;
 
 out_free:
-       kfree(slwt->srh);
        kfree(newts);
        return err;
 }
@@ -1021,12 +1086,7 @@ static void seg6_local_destroy_state(struct lwtunnel_state *lwt)
 {
        struct seg6_local_lwt *slwt = seg6_local_lwtunnel(lwt);
 
-       kfree(slwt->srh);
-
-       if (slwt->desc->attrs & (1 << SEG6_LOCAL_BPF)) {
-               kfree(slwt->bpf.name);
-               bpf_prog_put(slwt->bpf.prog);
-       }
+       destroy_attrs(slwt);
 
        return;
 }