drbd: prepare the transition from connector to genetlink
This adds the new API header and helper files.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/include/linux/genl_magic_func.h b/include/linux/genl_magic_func.h
new file mode 100644
index 0000000..8a86f65
--- /dev/null
+++ b/include/linux/genl_magic_func.h
@@ -0,0 +1,417 @@
+#ifndef GENL_MAGIC_FUNC_H
+#define GENL_MAGIC_FUNC_H
+
+#include <linux/genl_magic_struct.h>
+
+/*
+ * Extension of genl attribute validation policies {{{1
+ * {{{2
+ */
+
+/**
+ * nla_is_required - return true if this attribute is required
+ * @nla: netlink attribute
+ */
+static inline int nla_is_required(const struct nlattr *nla)
+{
+ return nla->nla_type & GENLA_F_REQUIRED;
+}
+
+/**
+ * nla_is_mandatory - return true if understanding this attribute is mandatory
+ * @nla: netlink attribute
+ * Note: REQUIRED attributes are implicitly MANDATORY as well
+ */
+static inline int nla_is_mandatory(const struct nlattr *nla)
+{
+ return nla->nla_type & (GENLA_F_MANDATORY | GENLA_F_REQUIRED);
+}
+
+/* Functionality to be integrated into nla_parse(), and validate_nla(),
+ * respectively.
+ *
+ * Enforcing the "mandatory" bit is done here,
+ * by rejecting unknown mandatory attributes.
+ *
+ * Part of enforcing the "required" flag would mean to embed it into
+ * nla_policy.type, and extending validate_nla(), which currently does
+ * BUG_ON(pt->type > NLA_TYPE_MAX); we have to work on existing kernels,
+ * so we cannot do that. Thats why enforcing "required" is done in the
+ * generated assignment functions below. */
+static int nla_check_unknown(int maxtype, struct nlattr *head, int len)
+{
+ struct nlattr *nla;
+ int rem;
+ nla_for_each_attr(nla, head, len, rem) {
+ __u16 type = nla_type(nla);
+ if (type > maxtype && nla_is_mandatory(nla))
+ return -EOPNOTSUPP;
+ }
+ return 0;
+}
+
+/*
+ * Magic: declare tla policy {{{1
+ * Magic: declare nested policies
+ * {{{2
+ */
+#undef GENL_mc_group
+#define GENL_mc_group(group)
+
+#undef GENL_notification
+#define GENL_notification(op_name, op_num, mcast_group, tla_list)
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list)
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+ [tag_name] = { .type = NLA_NESTED },
+
+static struct nla_policy CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy)[] = {
+#include GENL_MAGIC_INCLUDE_FILE
+};
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+static struct nla_policy s_name ## _nl_policy[] __read_mostly = \
+{ s_fields };
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, _type, __get, __put) \
+ [__nla_type(attr_nr)] = { .type = nla_type },
+
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, _type, maxlen, \
+ __get, __put) \
+ [__nla_type(attr_nr)] = { .type = nla_type, \
+ .len = maxlen - (nla_type == NLA_NUL_STRING) },
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+#ifndef __KERNEL__
+#ifndef pr_info
+#define pr_info(args...) fprintf(stderr, args);
+#endif
+#endif
+
+#if 1
+static void dprint_field(const char *dir, int nla_type,
+ const char *name, void *valp)
+{
+ __u64 val = valp ? *(__u32 *)valp : 1;
+ switch (nla_type) {
+ case NLA_U8: val = (__u8)val;
+ case NLA_U16: val = (__u16)val;
+ case NLA_U32: val = (__u32)val;
+ pr_info("%s attr %s: %d 0x%08x\n", dir,
+ name, (int)val, (unsigned)val);
+ break;
+ case NLA_U64:
+ val = *(__u64*)valp;
+ pr_info("%s attr %s: %lld 0x%08llx\n", dir,
+ name, (long long)val, (unsigned long long)val);
+ break;
+ case NLA_FLAG:
+ if (val)
+ pr_info("%s attr %s: set\n", dir, name);
+ break;
+ }
+}
+
+static void dprint_array(const char *dir, int nla_type,
+ const char *name, const char *val, unsigned len)
+{
+ switch (nla_type) {
+ case NLA_NUL_STRING:
+ if (len && val[len-1] == '\0')
+ len--;
+ pr_info("%s attr %s: [len:%u] '%s'\n", dir, name, len, val);
+ break;
+ default:
+ /* we can always show 4 byte,
+ * thats what nlattr are aligned to. */
+ pr_info("%s attr %s: [len:%u] %02x%02x%02x%02x ...\n",
+ dir, name, len, val[0], val[1], val[2], val[3]);
+ }
+}
+
+#define DPRINT_TLA(a, op, b) pr_info("%s %s %s\n", a, op, b);
+
+/* Name is a member field name of the struct s.
+ * If s is NULL (only parsing, no copy requested in *_from_attrs()),
+ * nla is supposed to point to the attribute containing the information
+ * corresponding to that struct member. */
+#define DPRINT_FIELD(dir, nla_type, name, s, nla) \
+ do { \
+ if (s) \
+ dprint_field(dir, nla_type, #name, &s->name); \
+ else if (nla) \
+ dprint_field(dir, nla_type, #name, \
+ (nla_type == NLA_FLAG) ? NULL \
+ : nla_data(nla)); \
+ } while (0)
+
+#define DPRINT_ARRAY(dir, nla_type, name, s, nla) \
+ do { \
+ if (s) \
+ dprint_array(dir, nla_type, #name, \
+ s->name, s->name ## _len); \
+ else if (nla) \
+ dprint_array(dir, nla_type, #name, \
+ nla_data(nla), nla_len(nla)); \
+ } while (0)
+#else
+#define DPRINT_TLA(a, op, b) do {} while (0)
+#define DPRINT_FIELD(dir, nla_type, name, s, nla) do {} while (0)
+#define DPRINT_ARRAY(dir, nla_type, name, s, nla) do {} while (0)
+#endif
+
+/*
+ * Magic: provide conversion functions {{{1
+ * populate struct from attribute table:
+ * {{{2
+ */
+
+/* processing of generic netlink messages is serialized.
+ * use one static buffer for parsing of nested attributes */
+static struct nlattr *nested_attr_tb[128];
+
+#ifndef BUILD_BUG_ON
+/* Force a compilation error if condition is true */
+#define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition))
+/* Force a compilation error if condition is true, but also produce a
+ result (of value 0 and type size_t), so the expression can be used
+ e.g. in a structure initializer (or where-ever else comma expressions
+ aren't permitted). */
+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
+#endif
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+ /* static, potentially unused */ \
+int s_name ## _from_attrs(struct s_name *s, struct nlattr *tb[]) \
+{ \
+ const int maxtype = ARRAY_SIZE(s_name ## _nl_policy)-1; \
+ struct nlattr *tla = tb[tag_number]; \
+ struct nlattr **ntb = nested_attr_tb; \
+ struct nlattr *nla; \
+ int err; \
+ BUILD_BUG_ON(ARRAY_SIZE(s_name ## _nl_policy) > ARRAY_SIZE(nested_attr_tb)); \
+ if (!tla) \
+ return -ENOMSG; \
+ DPRINT_TLA(#s_name, "<=-", #tag_name); \
+ err = nla_parse_nested(ntb, maxtype, tla, s_name ## _nl_policy); \
+ if (err) \
+ return err; \
+ err = nla_check_unknown(maxtype, nla_data(tla), nla_len(tla)); \
+ if (err) \
+ return err; \
+ \
+ s_fields \
+ return 0; \
+}
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+ nla = ntb[__nla_type(attr_nr)]; \
+ if (nla) { \
+ if (s) \
+ s->name = __get(nla); \
+ DPRINT_FIELD("<<", nla_type, name, s, nla); \
+ } else if ((attr_flag) & GENLA_F_REQUIRED) { \
+ pr_info("<< missing attr: %s\n", #name); \
+ return -ENOMSG; \
+ }
+
+/* validate_nla() already checked nla_len <= maxlen appropriately. */
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
+ nla = ntb[__nla_type(attr_nr)]; \
+ if (nla) { \
+ if (s) \
+ s->name ## _len = \
+ __get(s->name, nla, maxlen); \
+ DPRINT_ARRAY("<<", nla_type, name, s, nla); \
+ } else if ((attr_flag) & GENLA_F_REQUIRED) { \
+ pr_info("<< missing attr: %s\n", #name); \
+ return -ENOMSG; \
+ } \
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields)
+
+/*
+ * Magic: define op number to op name mapping {{{1
+ * {{{2
+ */
+const char *CONCAT_(GENL_MAGIC_FAMILY, _genl_cmd_to_str)(__u8 cmd)
+{
+ switch (cmd) {
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list) \
+ case op_num: return #op_name;
+#include GENL_MAGIC_INCLUDE_FILE
+ default:
+ return "unknown";
+ }
+}
+
+#ifdef __KERNEL__
+#include <linux/stringify.h>
+/*
+ * Magic: define genl_ops {{{1
+ * {{{2
+ */
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list) \
+{ \
+ handler \
+ .cmd = op_name, \
+ .policy = CONCAT_(GENL_MAGIC_FAMILY, _tla_nl_policy), \
+},
+
+#define ZZZ_genl_ops CONCAT_(GENL_MAGIC_FAMILY, _genl_ops)
+static struct genl_ops ZZZ_genl_ops[] __read_mostly = {
+#include GENL_MAGIC_INCLUDE_FILE
+};
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list)
+
+/*
+ * Define the genl_family, multicast groups, {{{1
+ * and provide register/unregister functions.
+ * {{{2
+ */
+#define ZZZ_genl_family CONCAT_(GENL_MAGIC_FAMILY, _genl_family)
+static struct genl_family ZZZ_genl_family __read_mostly = {
+ .id = GENL_ID_GENERATE,
+ .name = __stringify(GENL_MAGIC_FAMILY),
+ .version = GENL_MAGIC_VERSION,
+#ifdef GENL_MAGIC_FAMILY_HDRSZ
+ .hdrsize = NLA_ALIGN(GENL_MAGIC_FAMILY_HDRSZ),
+#endif
+ .maxattr = ARRAY_SIZE(drbd_tla_nl_policy)-1,
+};
+
+/*
+ * Magic: define multicast groups
+ * Magic: define multicast group registration helper
+ */
+#undef GENL_mc_group
+#define GENL_mc_group(group) \
+static struct genl_multicast_group \
+CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group) __read_mostly = { \
+ .name = #group, \
+}; \
+static int CONCAT_(GENL_MAGIC_FAMILY, _genl_multicast_ ## group)( \
+ struct sk_buff *skb, gfp_t flags) \
+{ \
+ unsigned int group_id = \
+ CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group).id; \
+ if (!group_id) \
+ return -EINVAL; \
+ return genlmsg_multicast(skb, 0, group_id, flags); \
+}
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void)
+{
+ int err = genl_register_family_with_ops(&ZZZ_genl_family,
+ ZZZ_genl_ops, ARRAY_SIZE(ZZZ_genl_ops));
+ if (err)
+ return err;
+#undef GENL_mc_group
+#define GENL_mc_group(group) \
+ err = genl_register_mc_group(&ZZZ_genl_family, \
+ &CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group)); \
+ if (err) \
+ goto fail; \
+ else \
+ pr_info("%s: mcg %s: %u\n", #group, \
+ __stringify(GENL_MAGIC_FAMILY), \
+ CONCAT_(GENL_MAGIC_FAMILY, _mcg_ ## group).id);
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+#undef GENL_mc_group
+#define GENL_mc_group(group)
+ return 0;
+fail:
+ genl_unregister_family(&ZZZ_genl_family);
+ return err;
+}
+
+void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void)
+{
+ genl_unregister_family(&ZZZ_genl_family);
+}
+
+/*
+ * Magic: provide conversion functions {{{1
+ * populate skb from struct.
+ * {{{2
+ */
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list)
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+static int s_name ## _to_skb(struct sk_buff *skb, struct s_name *s, \
+ const bool exclude_sensitive) \
+{ \
+ struct nlattr *tla = nla_nest_start(skb, tag_number); \
+ if (!tla) \
+ goto nla_put_failure; \
+ DPRINT_TLA(#s_name, "-=>", #tag_name); \
+ s_fields \
+ nla_nest_end(skb, tla); \
+ return 0; \
+ \
+nla_put_failure: \
+ if (tla) \
+ nla_nest_cancel(skb, tla); \
+ return -EMSGSIZE; \
+} \
+static inline int s_name ## _to_priv_skb(struct sk_buff *skb, \
+ struct s_name *s) \
+{ \
+ return s_name ## _to_skb(skb, s, 0); \
+} \
+static inline int s_name ## _to_unpriv_skb(struct sk_buff *skb, \
+ struct s_name *s) \
+{ \
+ return s_name ## _to_skb(skb, s, 1); \
+}
+
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+ if (!exclude_sensitive || !((attr_flag) & GENLA_F_SENSITIVE)) { \
+ DPRINT_FIELD(">>", nla_type, name, s, NULL); \
+ __put(skb, attr_nr, s->name); \
+ }
+
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
+ if (!exclude_sensitive || !((attr_flag) & GENLA_F_SENSITIVE)) { \
+ DPRINT_ARRAY(">>",nla_type, name, s, NULL); \
+ __put(skb, attr_nr, min_t(int, maxlen, \
+ s->name ## _len + (nla_type == NLA_NUL_STRING)),\
+ s->name); \
+ }
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+#endif /* __KERNEL__ */
+
+/* }}}1 */
+#endif /* GENL_MAGIC_FUNC_H */
+/* vim: set foldmethod=marker foldlevel=1 nofoldenable : */