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Subject[PATCH 08/18] drbd: prepare the transition from connector to genetlink
Date
From: Lars Ellenberg <lars.ellenberg@linbit.com>

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>
---
include/linux/drbd_genl.h | 349 +++++++++++++++++++++++++++++++
include/linux/drbd_genl_api.h | 55 +++++
include/linux/genl_magic_func.h | 417 +++++++++++++++++++++++++++++++++++++
include/linux/genl_magic_struct.h | 260 +++++++++++++++++++++++
4 files changed, 1081 insertions(+), 0 deletions(-)
create mode 100644 include/linux/drbd_genl.h
create mode 100644 include/linux/drbd_genl_api.h
create mode 100644 include/linux/genl_magic_func.h
create mode 100644 include/linux/genl_magic_struct.h
diff --git a/include/linux/drbd_genl.h b/include/linux/drbd_genl.h
new file mode 100644
index 0000000..84e1684
--- /dev/null
+++ b/include/linux/drbd_genl.h
@@ -0,0 +1,349 @@
+/*
+ * General overview:
+ * full generic netlink message:
+ * |nlmsghdr|genlmsghdr|<payload>
+ *
+ * payload:
+ * |optional fixed size family header|<sequence of netlink attributes>
+ *
+ * sequence of netlink attributes:
+ * I chose to have all "top level" attributes NLA_NESTED,
+ * corresponding to some real struct.
+ * So we have a sequence of |tla, len|<nested nla sequence>
+ *
+ * nested nla sequence:
+ * may be empty, or contain a sequence of netlink attributes
+ * representing the struct fields.
+ *
+ * The tag number of any field (regardless of containing struct)
+ * will be available as T_ ## field_name,
+ * so you cannot have the same field name in two differnt structs.
+ *
+ * The tag numbers themselves are per struct, though,
+ * so should always begin at 1 (not 0, that is the special "NLA_UNSPEC" type,
+ * which we won't use here).
+ * The tag numbers are used as index in the respective nla_policy array.
+ *
+ * GENL_struct(tag_name, tag_number, struct name, struct fields) - struct and policy
+ * genl_magic_struct.h
+ * generates the struct declaration,
+ * generates an entry in the tla enum,
+ * genl_magic_func.h
+ * generates an entry in the static tla policy
+ * with .type = NLA_NESTED
+ * generates the static <struct_name>_nl_policy definition,
+ * and static conversion functions
+ *
+ * genl_magic_func.h
+ *
+ * GENL_mc_group(group)
+ * genl_magic_struct.h
+ * does nothing
+ * genl_magic_func.h
+ * defines and registers the mcast group,
+ * and provides a send helper
+ *
+ * GENL_notification(op_name, op_num, mcast_group, tla list)
+ * These are notifications to userspace.
+ *
+ * genl_magic_struct.h
+ * generates an entry in the genl_ops enum,
+ * genl_magic_func.h
+ * does nothing
+ *
+ * mcast group: the name of the mcast group this notification should be
+ * expected on
+ * tla list: the list of expected top level attributes,
+ * for documentation and sanity checking.
+ *
+ * GENL_op(op_name, op_num, flags and handler, tla list) - "genl operations"
+ * These are requests from userspace.
+ *
+ * _op and _notification share the same "number space",
+ * op_nr will be assigned to "genlmsghdr->cmd"
+ *
+ * genl_magic_struct.h
+ * generates an entry in the genl_ops enum,
+ * genl_magic_func.h
+ * generates an entry in the static genl_ops array,
+ * and static register/unregister functions to
+ * genl_register_family_with_ops().
+ *
+ * flags and handler:
+ * GENL_op_init( .doit = x, .dumpit = y, .flags = something)
+ * GENL_doit(x) => .dumpit = NULL, .flags = GENL_ADMIN_PERM
+ * tla list: the list of expected top level attributes,
+ * for documentation and sanity checking.
+ */
+
+/*
+ * STRUCTS
+ */
+
+/* this is sent kernel -> userland on various error conditions, and contains
+ * informational textual info, which is supposedly human readable.
+ * The computer relevant return code is in the drbd_genlmsghdr.
+ */
+GENL_struct(DRBD_NLA_CFG_REPLY, 1, drbd_cfg_reply,
+ /* "arbitrary" size strings, nla_policy.len = 0 */
+ __str_field(1, GENLA_F_MANDATORY, info_text, 0)
+)
+
+/* Configuration requests typically need a context to operate on.
+ * Possible keys are device minor (fits in the drbd_genlmsghdr),
+ * the replication link (aka connection) name,
+ * and/or the replication group (aka resource) name,
+ * and the volume id within the resource. */
+GENL_struct(DRBD_NLA_CFG_CONTEXT, 2, drbd_cfg_context,
+ /* currently only 256 volumes per group,
+ * but maybe we still change that */
+ __u32_field(1, GENLA_F_MANDATORY, ctx_volume)
+ __str_field(2, GENLA_F_MANDATORY, ctx_conn_name, 128)
+)
+
+GENL_struct(DRBD_NLA_DISK_CONF, 3, disk_conf,
+ __u64_field(1, GENLA_F_MANDATORY, disk_size)
+ __str_field(2, GENLA_F_REQUIRED, backing_dev, 128)
+ __str_field(3, GENLA_F_REQUIRED, meta_dev, 128)
+ __u32_field(4, GENLA_F_REQUIRED, meta_dev_idx)
+ __u32_field(5, GENLA_F_MANDATORY, max_bio_bvecs)
+ __u32_field(6, GENLA_F_MANDATORY, on_io_error)
+ __u32_field(7, GENLA_F_MANDATORY, fencing)
+ __flg_field(8, GENLA_F_MANDATORY, no_disk_barrier)
+ __flg_field(9, GENLA_F_MANDATORY, no_disk_flush)
+ __flg_field(10, GENLA_F_MANDATORY, no_disk_drain)
+ __flg_field(11, GENLA_F_MANDATORY, no_md_flush)
+ __flg_field(12, GENLA_F_MANDATORY, use_bmbv)
+)
+
+GENL_struct(DRBD_NLA_SYNCER_CONF, 4, syncer_conf,
+ __u32_field(1, GENLA_F_MANDATORY, rate)
+ __u32_field(2, GENLA_F_MANDATORY, after)
+ __u32_field(3, GENLA_F_MANDATORY, al_extents)
+ __str_field(4, GENLA_F_MANDATORY, cpu_mask, 32)
+ __str_field(5, GENLA_F_MANDATORY, verify_alg, SHARED_SECRET_MAX)
+ __str_field(6, GENLA_F_MANDATORY, csums_alg, SHARED_SECRET_MAX)
+ __flg_field(7, GENLA_F_MANDATORY, use_rle)
+ __u32_field(8, GENLA_F_MANDATORY, on_no_data)
+ __u32_field(9, GENLA_F_MANDATORY, c_plan_ahead)
+ __u32_field(10, GENLA_F_MANDATORY, c_delay_target)
+ __u32_field(11, GENLA_F_MANDATORY, c_fill_target)
+ __u32_field(12, GENLA_F_MANDATORY, c_max_rate)
+ __u32_field(13, GENLA_F_MANDATORY, c_min_rate)
+)
+
+GENL_struct(DRBD_NLA_NET_CONF, 5, net_conf,
+ __str_field(1, GENLA_F_MANDATORY | GENLA_F_SENSITIVE,
+ shared_secret, SHARED_SECRET_MAX)
+ __str_field(2, GENLA_F_MANDATORY, cram_hmac_alg, SHARED_SECRET_MAX)
+ __str_field(3, GENLA_F_MANDATORY, integrity_alg, SHARED_SECRET_MAX)
+ __str_field(4, GENLA_F_REQUIRED, my_addr, 128)
+ __str_field(5, GENLA_F_REQUIRED, peer_addr, 128)
+ __u32_field(6, GENLA_F_REQUIRED, wire_protocol)
+ __u32_field(7, GENLA_F_MANDATORY, try_connect_int)
+ __u32_field(8, GENLA_F_MANDATORY, timeout)
+ __u32_field(9, GENLA_F_MANDATORY, ping_int)
+ __u32_field(10, GENLA_F_MANDATORY, ping_timeo)
+ __u32_field(11, GENLA_F_MANDATORY, sndbuf_size)
+ __u32_field(12, GENLA_F_MANDATORY, rcvbuf_size)
+ __u32_field(13, GENLA_F_MANDATORY, ko_count)
+ __u32_field(14, GENLA_F_MANDATORY, max_buffers)
+ __u32_field(15, GENLA_F_MANDATORY, max_epoch_size)
+ __u32_field(16, GENLA_F_MANDATORY, unplug_watermark)
+ __u32_field(17, GENLA_F_MANDATORY, after_sb_0p)
+ __u32_field(18, GENLA_F_MANDATORY, after_sb_1p)
+ __u32_field(19, GENLA_F_MANDATORY, after_sb_2p)
+ __u32_field(20, GENLA_F_MANDATORY, rr_conflict)
+ __u32_field(21, GENLA_F_MANDATORY, on_congestion)
+ __u32_field(22, GENLA_F_MANDATORY, cong_fill)
+ __u32_field(23, GENLA_F_MANDATORY, cong_extents)
+ __flg_field(24, GENLA_F_MANDATORY, two_primaries)
+ __flg_field(25, GENLA_F_MANDATORY, want_lose)
+ __flg_field(26, GENLA_F_MANDATORY, no_cork)
+ __flg_field(27, GENLA_F_MANDATORY, always_asbp)
+ __flg_field(28, GENLA_F_MANDATORY, dry_run)
+)
+
+GENL_struct(DRBD_NLA_SET_ROLE_PARMS, 6, set_role_parms,
+ __flg_field(1, GENLA_F_MANDATORY, assume_uptodate)
+)
+
+GENL_struct(DRBD_NLA_RESIZE_PARMS, 7, resize_parms,
+ __u64_field(1, GENLA_F_MANDATORY, resize_size)
+ __flg_field(2, GENLA_F_MANDATORY, resize_force)
+ __flg_field(3, GENLA_F_MANDATORY, no_resync)
+)
+
+GENL_struct(DRBD_NLA_STATE_INFO, 8, state_info,
+ /* the reason of the broadcast,
+ * if this is an event triggered broadcast. */
+ __u32_field(1, GENLA_F_MANDATORY, sib_reason)
+ __u32_field(2, GENLA_F_REQUIRED, current_state)
+ __u64_field(3, GENLA_F_MANDATORY, capacity)
+ __u64_field(4, GENLA_F_MANDATORY, ed_uuid)
+
+ /* These are for broadcast from after state change work.
+ * prev_state and new_state are from the moment the state change took
+ * place, new_state is not neccessarily the same as current_state,
+ * there may have been more state changes since. Which will be
+ * broadcasted soon, in their respective after state change work. */
+ __u32_field(5, GENLA_F_MANDATORY, prev_state)
+ __u32_field(6, GENLA_F_MANDATORY, new_state)
+
+ /* if we have a local disk: */
+ __bin_field(7, GENLA_F_MANDATORY, uuids, (UI_SIZE*sizeof(__u64)))
+ __u32_field(8, GENLA_F_MANDATORY, disk_flags)
+ __u64_field(9, GENLA_F_MANDATORY, bits_total)
+ __u64_field(10, GENLA_F_MANDATORY, bits_oos)
+ /* and in case resync or online verify is active */
+ __u64_field(11, GENLA_F_MANDATORY, bits_rs_total)
+ __u64_field(12, GENLA_F_MANDATORY, bits_rs_failed)
+
+ /* for pre and post notifications of helper execution */
+ __str_field(13, GENLA_F_MANDATORY, helper, 32)
+ __u32_field(14, GENLA_F_MANDATORY, helper_exit_code)
+)
+
+GENL_struct(DRBD_NLA_START_OV_PARMS, 9, start_ov_parms,
+ __u64_field(1, GENLA_F_MANDATORY, ov_start_sector)
+)
+
+GENL_struct(DRBD_NLA_NEW_C_UUID_PARMS, 10, new_c_uuid_parms,
+ __flg_field(1, GENLA_F_MANDATORY, clear_bm)
+)
+
+GENL_struct(DRBD_NLA_TIMEOUT_PARMS, 11, timeout_parms,
+ __u32_field(1, GENLA_F_REQUIRED, timeout_type)
+)
+
+GENL_struct(DRBD_NLA_DISCONNECT_PARMS, 12, disconnect_parms,
+ __flg_field(1, GENLA_F_MANDATORY, force_disconnect)
+)
+
+/*
+ * Notifications and commands (genlmsghdr->cmd)
+ */
+GENL_mc_group(events)
+
+ /* kernel -> userspace announcement of changes */
+GENL_notification(
+ DRBD_EVENT, 1, events,
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_STATE_INFO, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_NET_CONF, GENLA_F_MANDATORY)
+ GENL_tla_expected(DRBD_NLA_DISK_CONF, GENLA_F_MANDATORY)
+ GENL_tla_expected(DRBD_NLA_SYNCER_CONF, GENLA_F_MANDATORY)
+)
+
+ /* query kernel for specific or all info */
+GENL_op(
+ DRBD_ADM_GET_STATUS, 2,
+ GENL_op_init(
+ .doit = drbd_adm_get_status,
+ .dumpit = drbd_adm_get_status_all,
+ /* anyone may ask for the status,
+ * it is broadcasted anyways */
+ ),
+ /* To select the object .doit.
+ * Or a subset of objects in .dumpit. */
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_MANDATORY)
+)
+
+#if 0
+ /* TO BE DONE */
+ /* create or destroy resources, aka replication groups */
+GENL_op(DRBD_ADM_CREATE_RESOURCE, 3, GENL_doit(drbd_adm_create_resource),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_DELETE_RESOURCE, 4, GENL_doit(drbd_adm_delete_resource),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+#endif
+
+ /* add DRBD minor devices as volumes to resources */
+GENL_op(DRBD_ADM_ADD_MINOR, 5, GENL_doit(drbd_adm_add_minor),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_DEL_MINOR, 6, GENL_doit(drbd_adm_delete_minor),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+
+ /* add or delete replication links to resources */
+GENL_op(DRBD_ADM_ADD_LINK, 7, GENL_doit(drbd_adm_create_connection),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_DEL_LINK, 8, GENL_doit(drbd_adm_delete_connection),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+
+ /* operates on replication links */
+GENL_op(DRBD_ADM_SYNCER, 9,
+ GENL_doit(drbd_adm_syncer),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_SYNCER_CONF, GENLA_F_MANDATORY)
+)
+
+GENL_op(
+ DRBD_ADM_CONNECT, 10,
+ GENL_doit(drbd_adm_connect),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_NET_CONF, GENLA_F_REQUIRED)
+)
+
+GENL_op(DRBD_ADM_DISCONNECT, 11, GENL_doit(drbd_adm_disconnect),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+
+ /* operates on minors */
+GENL_op(DRBD_ADM_ATTACH, 12,
+ GENL_doit(drbd_adm_attach),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_DISK_CONF, GENLA_F_REQUIRED)
+)
+
+GENL_op(
+ DRBD_ADM_RESIZE, 13,
+ GENL_doit(drbd_adm_resize),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_RESIZE_PARMS, GENLA_F_MANDATORY)
+)
+
+ /* operates on all volumes within a resource */
+GENL_op(
+ DRBD_ADM_PRIMARY, 14,
+ GENL_doit(drbd_adm_set_role),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_SET_ROLE_PARMS, GENLA_F_REQUIRED)
+)
+
+GENL_op(
+ DRBD_ADM_SECONDARY, 15,
+ GENL_doit(drbd_adm_set_role),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_SET_ROLE_PARMS, GENLA_F_REQUIRED)
+)
+
+GENL_op(
+ DRBD_ADM_NEW_C_UUID, 16,
+ GENL_doit(drbd_adm_new_c_uuid),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED)
+ GENL_tla_expected(DRBD_NLA_NEW_C_UUID_PARMS, GENLA_F_MANDATORY)
+)
+
+GENL_op(
+ DRBD_ADM_START_OV, 17,
+ GENL_doit(drbd_adm_start_ov),
+ GENL_tla_expected(DRBD_NLA_START_OV_PARMS, GENLA_F_MANDATORY)
+)
+
+GENL_op(DRBD_ADM_DETACH, 18, GENL_doit(drbd_adm_detach),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_INVALIDATE, 19, GENL_doit(drbd_adm_invalidate),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_INVAL_PEER, 20, GENL_doit(drbd_adm_invalidate_peer),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_PAUSE_SYNC, 21, GENL_doit(drbd_adm_pause_sync),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_RESUME_SYNC, 22, GENL_doit(drbd_adm_resume_sync),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_SUSPEND_IO, 23, GENL_doit(drbd_adm_suspend_io),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_RESUME_IO, 24, GENL_doit(drbd_adm_resume_io),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_OUTDATE, 25, GENL_doit(drbd_adm_outdate),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
+GENL_op(DRBD_ADM_GET_TIMEOUT_TYPE, 26, GENL_doit(drbd_adm_get_timeout_type),
+ GENL_tla_expected(DRBD_NLA_CFG_CONTEXT, GENLA_F_REQUIRED))
diff --git a/include/linux/drbd_genl_api.h b/include/linux/drbd_genl_api.h
new file mode 100644
index 0000000..9ef50d5
--- /dev/null
+++ b/include/linux/drbd_genl_api.h
@@ -0,0 +1,55 @@
+#ifndef DRBD_GENL_STRUCT_H
+#define DRBD_GENL_STRUCT_H
+
+/**
+ * struct drbd_genlmsghdr - DRBD specific header used in NETLINK_GENERIC requests
+ * @minor:
+ * For admin requests (user -> kernel): which minor device to operate on.
+ * For (unicast) replies or informational (broadcast) messages
+ * (kernel -> user): which minor device the information is about.
+ * If we do not operate on minors, but on connections or resources,
+ * the minor value shall be (~0), and the attribute DRBD_NLA_CFG_CONTEXT
+ * is used instead.
+ * @flags: possible operation modifiers (relevant only for user->kernel):
+ * DRBD_GENL_F_SET_DEFAULTS
+ * @volume:
+ * When creating a new minor (adding it to a resource), the resource needs
+ * to know which volume number within the resource this is supposed to be.
+ * The volume number corresponds to the same volume number on the remote side,
+ * whereas the minor number on the remote side may be different
+ * (union with flags).
+ * @ret_code: kernel->userland unicast cfg reply return code (union with flags);
+ */
+struct drbd_genlmsghdr {
+ __u32 minor;
+ union {
+ __u32 flags;
+ __s32 ret_code;
+ };
+};
+
+/* To be used in drbd_genlmsghdr.flags */
+enum {
+ DRBD_GENL_F_SET_DEFAULTS = 1,
+};
+
+enum drbd_state_info_bcast_reason {
+ SIB_GET_STATUS_REPLY = 1,
+ SIB_STATE_CHANGE = 2,
+ SIB_HELPER_PRE = 3,
+ SIB_HELPER_POST = 4,
+ SIB_SYNC_PROGRESS = 5,
+};
+
+/* hack around predefined gcc/cpp "linux=1",
+ * we cannot possibly include <1/drbd_genl.h> */
+#undef linux
+
+#include <linux/drbd.h>
+#define GENL_MAGIC_VERSION API_VERSION
+#define GENL_MAGIC_FAMILY drbd
+#define GENL_MAGIC_FAMILY_HDRSZ sizeof(struct drbd_genlmsghdr)
+#define GENL_MAGIC_INCLUDE_FILE <linux/drbd_genl.h>
+#include <linux/genl_magic_struct.h>
+
+#endif
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 : */
diff --git a/include/linux/genl_magic_struct.h b/include/linux/genl_magic_struct.h
new file mode 100644
index 0000000..745ebfd
--- /dev/null
+++ b/include/linux/genl_magic_struct.h
@@ -0,0 +1,260 @@
+#ifndef GENL_MAGIC_STRUCT_H
+#define GENL_MAGIC_STRUCT_H
+
+#ifndef GENL_MAGIC_FAMILY
+# error "you need to define GENL_MAGIC_FAMILY before inclusion"
+#endif
+
+#ifndef GENL_MAGIC_VERSION
+# error "you need to define GENL_MAGIC_VERSION before inclusion"
+#endif
+
+#ifndef GENL_MAGIC_INCLUDE_FILE
+# error "you need to define GENL_MAGIC_INCLUDE_FILE before inclusion"
+#endif
+
+#include <linux/genetlink.h>
+#include <linux/types.h>
+
+#define CONCAT__(a,b) a ## b
+#define CONCAT_(a,b) CONCAT__(a,b)
+
+extern int CONCAT_(GENL_MAGIC_FAMILY, _genl_register)(void);
+extern void CONCAT_(GENL_MAGIC_FAMILY, _genl_unregister)(void);
+
+/*
+ * Extension of genl attribute validation policies {{{2
+ */
+
+/**
+ * GENLA_F_FLAGS - policy type flags to ease compatible ABI evolvement
+ *
+ * @GENLA_F_REQUIRED: attribute has to be present, or message is considered invalid.
+ * Adding new REQUIRED attributes breaks ABI compatibility, so don't do that.
+ *
+ * @GENLA_F_MANDATORY: if present, receiver _must_ understand it.
+ * Without this, unknown attributes (> maxtype) are _silently_ ignored
+ * by validate_nla().
+ *
+ * To be used for API extensions, so older kernel can reject requests for not
+ * yet implemented features, if newer userland tries to use them even though
+ * the genl_family version clearly indicates they are not available.
+ *
+ * @GENLA_F_MAY_IGNORE: To clearly document the fact, for good measure.
+ * To be used for API extensions for things that have sane defaults,
+ * so newer userland can still talk to older kernel, knowing it will
+ * silently ignore these attributes if not yet known.
+ *
+ * NOTE: These flags overload
+ * NLA_F_NESTED (1 << 15)
+ * NLA_F_NET_BYTEORDER (1 << 14)
+ * from linux/netlink.h, which are not useful for validate_nla():
+ * NET_BYTEORDER is not used anywhere, and NESTED would be specified by setting
+ * .type = NLA_NESTED in the appropriate policy.
+ *
+ * See also: nla_type()
+ */
+enum {
+ GENLA_F_MAY_IGNORE = 0,
+ GENLA_F_MANDATORY = 1 << 14,
+ GENLA_F_REQUIRED = 1 << 15,
+
+ /* This will not be present in the __u16 .nla_type, but can be
+ * triggered on in <struct>_to_skb, to exclude "sensitive"
+ * information from broadcasts, or on unpriviledged get requests.
+ * This is useful because genetlink multicast groups can be listened in
+ * on by anyone. */
+ GENLA_F_SENSITIVE = 1 << 16,
+};
+
+#define __nla_type(x) ((__u16)((__u16)(x) & (__u16)NLA_TYPE_MASK))
+
+/* }}}1
+ * MAGIC
+ * multi-include macro expansion magic starts here
+ */
+
+/* MAGIC helpers {{{2 */
+
+/* possible field types */
+#define __flg_field(attr_nr, attr_flag, name) \
+ __field(attr_nr, attr_flag, name, NLA_FLAG, char, \
+ nla_get_flag, __nla_put_flag)
+#define __u8_field(attr_nr, attr_flag, name) \
+ __field(attr_nr, attr_flag, name, NLA_U8, unsigned char, \
+ nla_get_u8, NLA_PUT_U8)
+#define __u16_field(attr_nr, attr_flag, name) \
+ __field(attr_nr, attr_flag, name, NLA_U16, __u16, \
+ nla_get_u16, NLA_PUT_U16)
+#define __u32_field(attr_nr, attr_flag, name) \
+ __field(attr_nr, attr_flag, name, NLA_U32, __u32, \
+ nla_get_u32, NLA_PUT_U32)
+#define __u64_field(attr_nr, attr_flag, name) \
+ __field(attr_nr, attr_flag, name, NLA_U64, __u64, \
+ nla_get_u64, NLA_PUT_U64)
+#define __str_field(attr_nr, attr_flag, name, maxlen) \
+ __array(attr_nr, attr_flag, name, NLA_NUL_STRING, char, maxlen, \
+ nla_strlcpy, NLA_PUT)
+#define __bin_field(attr_nr, attr_flag, name, maxlen) \
+ __array(attr_nr, attr_flag, name, NLA_BINARY, char, maxlen, \
+ nla_memcpy, NLA_PUT)
+
+#define __nla_put_flag(skb, attrtype, value) \
+ do { \
+ if (value) \
+ NLA_PUT_FLAG(skb, attrtype); \
+ } while (0)
+
+#define GENL_op_init(args...) args
+#define GENL_doit(handler) \
+ .doit = handler, \
+ .flags = GENL_ADMIN_PERM,
+#define GENL_dumpit(handler) \
+ .dumpit = handler, \
+ .flags = GENL_ADMIN_PERM,
+
+/* }}}1
+ * Magic: define the enum symbols for genl_ops
+ * Magic: define the enum symbols for top level attributes
+ * Magic: define the enum symbols for nested attributes
+ * {{{2
+ */
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields)
+
+#undef GENL_mc_group
+#define GENL_mc_group(group)
+
+#undef GENL_notification
+#define GENL_notification(op_name, op_num, mcast_group, tla_list) \
+ op_name = op_num,
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, tla_list) \
+ op_name = op_num,
+
+enum {
+#include GENL_MAGIC_INCLUDE_FILE
+};
+
+#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, attr_list)
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+ tag_name = tag_number,
+
+enum {
+#include GENL_MAGIC_INCLUDE_FILE
+};
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+enum { \
+ s_fields \
+};
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+ T_ ## name = (__u16)(attr_nr | attr_flag),
+
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
+ T_ ## name = (__u16)(attr_nr | attr_flag),
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+/* }}}1
+ * Magic: compile time assert unique numbers for operations
+ * Magic: -"- unique numbers for top level attributes
+ * Magic: -"- unique numbers for nested attributes
+ * {{{2
+ */
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields)
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, attr_list) \
+ case op_name:
+
+#undef GENL_notification
+#define GENL_notification(op_name, op_num, mcast_group, tla_list) \
+ case op_name:
+
+static inline void ct_assert_unique_operations(void)
+{
+ switch (0) {
+#include GENL_MAGIC_INCLUDE_FILE
+ ;
+ }
+}
+
+#undef GENL_op
+#define GENL_op(op_name, op_num, handler, attr_list)
+
+#undef GENL_notification
+#define GENL_notification(op_name, op_num, mcast_group, tla_list)
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+ case tag_number:
+
+static inline void ct_assert_unique_top_level_attributes(void)
+{
+ switch (0) {
+#include GENL_MAGIC_INCLUDE_FILE
+ ;
+ }
+}
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+static inline void ct_assert_unique_ ## s_name ## _attributes(void) \
+{ \
+ switch (0) { \
+ s_fields \
+ ; \
+ } \
+}
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+ case attr_nr:
+
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
+ case attr_nr:
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+/* }}}1
+ * Magic: declare structs
+ * struct <name> {
+ * fields
+ * };
+ * {{{2
+ */
+
+#undef GENL_struct
+#define GENL_struct(tag_name, tag_number, s_name, s_fields) \
+struct s_name { s_fields };
+
+#undef __field
+#define __field(attr_nr, attr_flag, name, nla_type, type, __get, __put) \
+ type name;
+
+#undef __array
+#define __array(attr_nr, attr_flag, name, nla_type, type, maxlen, __get, __put) \
+ type name[maxlen]; \
+ __u32 name ## _len;
+
+#include GENL_MAGIC_INCLUDE_FILE
+
+/* }}}1 */
+#endif /* GENL_MAGIC_STRUCT_H */
+/* vim: set foldmethod=marker nofoldenable : */
--
1.7.4.1


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