genetlink: introduce split op representation

We currently have two forms of operations - small ops and "full" ops
(or just ops). The former does not have pointers for some of the less
commonly used features (namely dump start/done and policy).

The "full" ops, however, still don't contain all the necessary
information. In particular the policy is per command ID, while
do and dump often accept different attributes. It's also not
possible to define different pre_doit and post_doit callbacks
for different commands within the family.

At the same time a lot of commands do not support dumping and
therefore all the dump-related information is wasted space.

Create a new command representation which can hold info about
a do implementation or a dump implementation, but not both at
the same time.

Use this new representation on the command execution path
(genl_family_rcv_msg) as we either run a do or a dump and
don't have to create a "full" op there.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 81180fc6526a1b6e8900a0d6a8548353779ad77d..4be7989c451bff67415cf8f273fadc2ec1e4b564 100644 (file)
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -18,7 +18,7 @@ struct genl_multicast_group {
        u8                      flags;
 };
 
-struct genl_ops;
+struct genl_split_ops;
 struct genl_info;
 
 /**
@@ -66,10 +66,10 @@ struct genl_family {
        u8                      n_mcgrps;
        u8                      resv_start_op;
        const struct nla_policy *policy;
-       int                     (*pre_doit)(const struct genl_ops *ops,
+       int                     (*pre_doit)(const struct genl_split_ops *ops,
                                            struct sk_buff *skb,
                                            struct genl_info *info);
-       void                    (*post_doit)(const struct genl_ops *ops,
+       void                    (*post_doit)(const struct genl_split_ops *ops,
                                             struct sk_buff *skb,
                                             struct genl_info *info);
        const struct genl_ops * ops;
@@ -182,6 +182,58 @@ struct genl_ops {
        u8                      validate;
 };
 
+/**
+ * struct genl_split_ops - generic netlink operations (do/dump split version)
+ * @cmd: command identifier
+ * @internal_flags: flags used by the family
+ * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
+ * @validate: validation flags from enum genl_validate_flags
+ * @policy: netlink policy (takes precedence over family policy)
+ * @maxattr: maximum number of attributes supported
+ *
+ * Do callbacks:
+ * @pre_doit: called before an operation's @doit callback, it may
+ *     do additional, common, filtering and return an error
+ * @doit: standard command callback
+ * @post_doit: called after an operation's @doit callback, it may
+ *     undo operations done by pre_doit, for example release locks
+ *
+ * Dump callbacks:
+ * @start: start callback for dumps
+ * @dumpit: callback for dumpers
+ * @done: completion callback for dumps
+ *
+ * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
+ * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
+ * Exactly one of those flags must be set.
+ */
+struct genl_split_ops {
+       union {
+               struct {
+                       int (*pre_doit)(const struct genl_split_ops *ops,
+                                       struct sk_buff *skb,
+                                       struct genl_info *info);
+                       int (*doit)(struct sk_buff *skb,
+                                   struct genl_info *info);
+                       void (*post_doit)(const struct genl_split_ops *ops,
+                                         struct sk_buff *skb,
+                                         struct genl_info *info);
+               };
+               struct {
+                       int (*start)(struct netlink_callback *cb);
+                       int (*dumpit)(struct sk_buff *skb,
+                                     struct netlink_callback *cb);
+                       int (*done)(struct netlink_callback *cb);
+               };
+       };
+       const struct nla_policy *policy;
+       unsigned int            maxattr;
+       u8                      cmd;
+       u8                      internal_flags;
+       u8                      flags;
+       u8                      validate;
+};
+
 /**
  * struct genl_dumpit_info - info that is available during dumpit op call
  * @family: generic netlink family - for internal genl code usage
@@ -190,7 +242,7 @@ struct genl_ops {
  */
 struct genl_dumpit_info {
        const struct genl_family *family;
-       struct genl_ops op;
+       struct genl_split_ops op;
        struct nlattr **attrs;
 };
 

diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index a5e4a4e976cf3c8dc042ede58e812bbae5d5401f..ad5714f737be275fa0394981b4a4bc072c861ebf 100644 (file)
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -1267,7 +1267,8 @@ batadv_get_vlan_from_info(struct batadv_priv *bat_priv, struct net *net,
  *
  * Return: 0 on success or negative error number in case of failure
  */
-static int batadv_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static int batadv_pre_doit(const struct genl_split_ops *ops,
+                          struct sk_buff *skb,
                           struct genl_info *info)
 {
        struct net *net = genl_info_net(info);
@@ -1332,7 +1333,8 @@ err_put_softif:
  * @skb: Netlink message with request data
  * @info: receiver information
  */
-static void batadv_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static void batadv_post_doit(const struct genl_split_ops *ops,
+                            struct sk_buff *skb,
                             struct genl_info *info)
 {
        struct batadv_hard_iface *hard_iface;

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 2dcf2bcc35272dca28a6fa66450b6400d72a1c5f..40fcdded57e6b2bd52703f80fe171b56a907dfc2 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -770,7 +770,7 @@ devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
 #define DEVLINK_NL_FLAG_NEED_RATE_NODE         BIT(3)
 #define DEVLINK_NL_FLAG_NEED_LINECARD          BIT(4)
 
-static int devlink_nl_pre_doit(const struct genl_ops *ops,
+static int devlink_nl_pre_doit(const struct genl_split_ops *ops,
                               struct sk_buff *skb, struct genl_info *info)
 {
        struct devlink_linecard *linecard;
@@ -828,7 +828,7 @@ unlock:
        return err;
 }
 
-static void devlink_nl_post_doit(const struct genl_ops *ops,
+static void devlink_nl_post_doit(const struct genl_split_ops *ops,
                                 struct sk_buff *skb, struct genl_info *info)
 {
        struct devlink_linecard *linecard;

diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 11aa6e8a309817cb356dc8f39e23c63261c14fe0..5a782d1d8fd3dd69bc96c5c0c82b9485a9695e9f 100644 (file)
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -1620,7 +1620,7 @@ static const struct genl_small_ops dropmon_ops[] = {
        },
 };
 
-static int net_dm_nl_pre_doit(const struct genl_ops *ops,
+static int net_dm_nl_pre_doit(const struct genl_split_ops *ops,
                              struct sk_buff *skb, struct genl_info *info)
 {
        mutex_lock(&net_dm_mutex);
@@ -1628,7 +1628,7 @@ static int net_dm_nl_pre_doit(const struct genl_ops *ops,
        return 0;
 }
 
-static void net_dm_nl_post_doit(const struct genl_ops *ops,
+static void net_dm_nl_post_doit(const struct genl_split_ops *ops,
                                struct sk_buff *skb, struct genl_info *info)
 {
        mutex_unlock(&net_dm_mutex);

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index 38c4f3cb010e89f8cd31c453e2fdd1f2291886c5..b33d1b5eda87d5e9c30111f6531c959897b68123 100644 (file)
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -2157,7 +2157,8 @@ static int nl802154_del_llsec_seclevel(struct sk_buff *skb,
 #define NL802154_FLAG_CHECK_NETDEV_UP  0x08
 #define NL802154_FLAG_NEED_WPAN_DEV    0x10
 
-static int nl802154_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static int nl802154_pre_doit(const struct genl_split_ops *ops,
+                            struct sk_buff *skb,
                             struct genl_info *info)
 {
        struct cfg802154_registered_device *rdev;
@@ -2219,7 +2220,8 @@ static int nl802154_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
        return 0;
 }
 
-static void nl802154_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static void nl802154_post_doit(const struct genl_split_ops *ops,
+                              struct sk_buff *skb,
                               struct genl_info *info)
 {
        if (info->user_ptr[1]) {

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 0a7a856e9ce021337dd38f576f72069cb86d6d58..c66299740c0599af015f23eb357801a3c0fb8919 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -189,6 +189,51 @@ static int genl_get_cmd(u32 cmd, const struct genl_family *family,
        return genl_get_cmd_small(cmd, family, op);
 }
 
+static void
+genl_cmd_full_to_split(struct genl_split_ops *op,
+                      const struct genl_family *family,
+                      const struct genl_ops *full, u8 flags)
+{
+       if (flags & GENL_CMD_CAP_DUMP) {
+               op->start       = full->start;
+               op->dumpit      = full->dumpit;
+               op->done        = full->done;
+       } else {
+               op->pre_doit    = family->pre_doit;
+               op->doit        = full->doit;
+               op->post_doit   = family->post_doit;
+       }
+
+       op->policy              = full->policy;
+       op->maxattr             = full->maxattr;
+
+       op->cmd                 = full->cmd;
+       op->internal_flags      = full->internal_flags;
+       op->flags               = full->flags;
+       op->validate            = full->validate;
+
+       /* Make sure flags include the GENL_CMD_CAP_DO / GENL_CMD_CAP_DUMP */
+       op->flags               |= flags;
+}
+
+static int
+genl_get_cmd_split(u32 cmd, u8 flags, const struct genl_family *family,
+                  struct genl_split_ops *op)
+{
+       struct genl_ops full;
+       int err;
+
+       err = genl_get_cmd(cmd, family, &full);
+       if (err) {
+               memset(op, 0, sizeof(*op));
+               return err;
+       }
+
+       genl_cmd_full_to_split(op, family, &full, flags);
+
+       return 0;
+}
+
 static void genl_get_cmd_by_index(unsigned int i,
                                  const struct genl_family *family,
                                  struct genl_ops *op)
@@ -544,7 +589,7 @@ static struct nlattr **
 genl_family_rcv_msg_attrs_parse(const struct genl_family *family,
                                struct nlmsghdr *nlh,
                                struct netlink_ext_ack *extack,
-                               const struct genl_ops *ops,
+                               const struct genl_split_ops *ops,
                                int hdrlen,
                                enum genl_validate_flags no_strict_flag)
 {
@@ -580,18 +625,19 @@ struct genl_start_context {
        const struct genl_family *family;
        struct nlmsghdr *nlh;
        struct netlink_ext_ack *extack;
-       const struct genl_ops *ops;
+       const struct genl_split_ops *ops;
        int hdrlen;
 };
 
 static int genl_start(struct netlink_callback *cb)
 {
        struct genl_start_context *ctx = cb->data;
-       const struct genl_ops *ops = ctx->ops;
+       const struct genl_split_ops *ops;
        struct genl_dumpit_info *info;
        struct nlattr **attrs = NULL;
        int rc = 0;
 
+       ops = ctx->ops;
        if (ops->validate & GENL_DONT_VALIDATE_DUMP)
                goto no_attrs;
 
@@ -633,7 +679,7 @@ no_attrs:
 
 static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
+       const struct genl_split_ops *ops = &genl_dumpit_info(cb)->op;
        int rc;
 
        genl_lock();
@@ -645,7 +691,7 @@ static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 static int genl_lock_done(struct netlink_callback *cb)
 {
        const struct genl_dumpit_info *info = genl_dumpit_info(cb);
-       const struct genl_ops *ops = &info->op;
+       const struct genl_split_ops *ops = &info->op;
        int rc = 0;
 
        if (ops->done) {
@@ -661,7 +707,7 @@ static int genl_lock_done(struct netlink_callback *cb)
 static int genl_parallel_done(struct netlink_callback *cb)
 {
        const struct genl_dumpit_info *info = genl_dumpit_info(cb);
-       const struct genl_ops *ops = &info->op;
+       const struct genl_split_ops *ops = &info->op;
        int rc = 0;
 
        if (ops->done)
@@ -675,7 +721,7 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
                                      struct sk_buff *skb,
                                      struct nlmsghdr *nlh,
                                      struct netlink_ext_ack *extack,
-                                     const struct genl_ops *ops,
+                                     const struct genl_split_ops *ops,
                                      int hdrlen, struct net *net)
 {
        struct genl_start_context ctx;
@@ -721,7 +767,7 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
                                    struct sk_buff *skb,
                                    struct nlmsghdr *nlh,
                                    struct netlink_ext_ack *extack,
-                                   const struct genl_ops *ops,
+                                   const struct genl_split_ops *ops,
                                    int hdrlen, struct net *net)
 {
        struct nlattr **attrbuf;
@@ -747,16 +793,16 @@ static int genl_family_rcv_msg_doit(const struct genl_family *family,
        genl_info_net_set(&info, net);
        memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 
-       if (family->pre_doit) {
-               err = family->pre_doit(ops, skb, &info);
+       if (ops->pre_doit) {
+               err = ops->pre_doit(ops, skb, &info);
                if (err)
                        goto out;
        }
 
        err = ops->doit(skb, &info);
 
-       if (family->post_doit)
-               family->post_doit(ops, skb, &info);
+       if (ops->post_doit)
+               ops->post_doit(ops, skb, &info);
 
 out:
        genl_family_rcv_msg_attrs_free(attrbuf);
@@ -801,8 +847,9 @@ static int genl_family_rcv_msg(const struct genl_family *family,
 {
        struct net *net = sock_net(skb->sk);
        struct genlmsghdr *hdr = nlmsg_data(nlh);
-       struct genl_ops op;
+       struct genl_split_ops op;
        int hdrlen;
+       u8 flags;
 
        /* this family doesn't exist in this netns */
        if (!family->netnsok && !net_eq(net, &init_net))
@@ -815,7 +862,9 @@ static int genl_family_rcv_msg(const struct genl_family *family,
        if (genl_header_check(family, nlh, hdr, extack))
                return -EINVAL;
 
-       if (genl_get_cmd(hdr->cmd, family, &op))
+       flags = (nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP ?
+               GENL_CMD_CAP_DUMP : GENL_CMD_CAP_DO;
+       if (genl_get_cmd_split(hdr->cmd, flags, family, &op))
                return -EOPNOTSUPP;
 
        if ((op.flags & GENL_ADMIN_PERM) &&
@@ -826,7 +875,7 @@ static int genl_family_rcv_msg(const struct genl_family *family,
            !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
                return -EPERM;
 
-       if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
+       if (flags & GENL_CMD_CAP_DUMP)
                return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
                                                  &op, hdrlen, net);
        else

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 148f66edb0158c99a8d48a02885f907ee0906565..1ad0326ff4dc95961040ddd5022f68bd4cb487da 100644 (file)
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -16140,7 +16140,8 @@ static u32 nl80211_internal_flags[] = {
 #undef SELECTOR
 };
 
-static int nl80211_pre_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static int nl80211_pre_doit(const struct genl_split_ops *ops,
+                           struct sk_buff *skb,
                            struct genl_info *info)
 {
        struct cfg80211_registered_device *rdev = NULL;
@@ -16241,7 +16242,8 @@ out_unlock:
        return err;
 }
 
-static void nl80211_post_doit(const struct genl_ops *ops, struct sk_buff *skb,
+static void nl80211_post_doit(const struct genl_split_ops *ops,
+                             struct sk_buff *skb,
                              struct genl_info *info)
 {
        u32 internal_flags = nl80211_internal_flags[ops->internal_flags];