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-rw-r--r--net/netlink/genetlink.c235
1 files changed, 228 insertions, 7 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index b9ab62f938d..e146531faf1 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -3,6 +3,7 @@
*
* Authors: Jamal Hadi Salim
* Thomas Graf <tgraf@suug.ch>
+ * Johannes Berg <johannes@sipsolutions.net>
*/
#include <linux/module.h>
@@ -13,6 +14,7 @@
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/mutex.h>
+#include <linux/bitmap.h>
#include <net/sock.h>
#include <net/genetlink.h>
@@ -42,6 +44,16 @@ static void genl_unlock(void)
#define GENL_FAM_TAB_MASK (GENL_FAM_TAB_SIZE - 1)
static struct list_head family_ht[GENL_FAM_TAB_SIZE];
+/*
+ * Bitmap of multicast groups that are currently in use.
+ *
+ * To avoid an allocation at boot of just one unsigned long,
+ * declare it global instead.
+ * Bit 0 is marked as already used since group 0 is invalid.
+ */
+static unsigned long mc_group_start = 0x1;
+static unsigned long *mc_groups = &mc_group_start;
+static unsigned long mc_groups_longs = 1;
static int genl_ctrl_event(int event, void *data);
@@ -116,6 +128,114 @@ static inline u16 genl_generate_id(void)
return id_gen_idx;
}
+static struct genl_multicast_group notify_grp;
+
+/**
+ * genl_register_mc_group - register a multicast group
+ *
+ * Registers the specified multicast group and notifies userspace
+ * about the new group.
+ *
+ * Returns 0 on success or a negative error code.
+ *
+ * @family: The generic netlink family the group shall be registered for.
+ * @grp: The group to register, must have a name.
+ */
+int genl_register_mc_group(struct genl_family *family,
+ struct genl_multicast_group *grp)
+{
+ int id;
+ unsigned long *new_groups;
+ int err;
+
+ BUG_ON(grp->name[0] == '\0');
+
+ genl_lock();
+
+ /* special-case our own group */
+ if (grp == &notify_grp)
+ id = GENL_ID_CTRL;
+ else
+ id = find_first_zero_bit(mc_groups,
+ mc_groups_longs * BITS_PER_LONG);
+
+
+ if (id >= mc_groups_longs * BITS_PER_LONG) {
+ size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long);
+
+ if (mc_groups == &mc_group_start) {
+ new_groups = kzalloc(nlen, GFP_KERNEL);
+ if (!new_groups) {
+ err = -ENOMEM;
+ goto out;
+ }
+ mc_groups = new_groups;
+ *mc_groups = mc_group_start;
+ } else {
+ new_groups = krealloc(mc_groups, nlen, GFP_KERNEL);
+ if (!new_groups) {
+ err = -ENOMEM;
+ goto out;
+ }
+ mc_groups = new_groups;
+ mc_groups[mc_groups_longs] = 0;
+ }
+ mc_groups_longs++;
+ }
+
+ err = netlink_change_ngroups(genl_sock,
+ sizeof(unsigned long) * NETLINK_GENERIC);
+ if (err)
+ goto out;
+
+ grp->id = id;
+ set_bit(id, mc_groups);
+ list_add_tail(&grp->list, &family->mcast_groups);
+ grp->family = family;
+
+ genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp);
+ out:
+ genl_unlock();
+ return 0;
+}
+EXPORT_SYMBOL(genl_register_mc_group);
+
+/**
+ * genl_unregister_mc_group - unregister a multicast group
+ *
+ * Unregisters the specified multicast group and notifies userspace
+ * about it. All current listeners on the group are removed.
+ *
+ * Note: It is not necessary to unregister all multicast groups before
+ * unregistering the family, unregistering the family will cause
+ * all assigned multicast groups to be unregistered automatically.
+ *
+ * @family: Generic netlink family the group belongs to.
+ * @grp: The group to unregister, must have been registered successfully
+ * previously.
+ */
+void genl_unregister_mc_group(struct genl_family *family,
+ struct genl_multicast_group *grp)
+{
+ BUG_ON(grp->family != family);
+ genl_lock();
+ netlink_clear_multicast_users(genl_sock, grp->id);
+ clear_bit(grp->id, mc_groups);
+ list_del(&grp->list);
+ genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
+ grp->id = 0;
+ grp->family = NULL;
+ genl_unlock();
+}
+
+static void genl_unregister_mc_groups(struct genl_family *family)
+{
+ struct genl_multicast_group *grp, *tmp;
+
+ list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list)
+ genl_unregister_mc_group(family, grp);
+}
+
/**
* genl_register_ops - register generic netlink operations
* @family: generic netlink family
@@ -216,6 +336,7 @@ int genl_register_family(struct genl_family *family)
goto errout;
INIT_LIST_HEAD(&family->ops_list);
+ INIT_LIST_HEAD(&family->mcast_groups);
genl_lock();
@@ -275,6 +396,8 @@ int genl_unregister_family(struct genl_family *family)
{
struct genl_family *rc;
+ genl_unregister_mc_groups(family);
+
genl_lock();
list_for_each_entry(rc, genl_family_chain(family->id), family_list) {
@@ -410,6 +533,67 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
nla_nest_end(skb, nla_ops);
}
+ if (!list_empty(&family->mcast_groups)) {
+ struct genl_multicast_group *grp;
+ struct nlattr *nla_grps;
+ int idx = 1;
+
+ nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+ if (nla_grps == NULL)
+ goto nla_put_failure;
+
+ list_for_each_entry(grp, &family->mcast_groups, list) {
+ struct nlattr *nest;
+
+ nest = nla_nest_start(skb, idx++);
+ if (nest == NULL)
+ goto nla_put_failure;
+
+ NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
+ NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
+ grp->name);
+
+ nla_nest_end(skb, nest);
+ }
+ nla_nest_end(skb, nla_grps);
+ }
+
+ return genlmsg_end(skb, hdr);
+
+nla_put_failure:
+ return genlmsg_cancel(skb, hdr);
+}
+
+static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 pid,
+ u32 seq, u32 flags, struct sk_buff *skb,
+ u8 cmd)
+{
+ void *hdr;
+ struct nlattr *nla_grps;
+ struct nlattr *nest;
+
+ hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
+ if (hdr == NULL)
+ return -1;
+
+ NLA_PUT_STRING(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name);
+ NLA_PUT_U16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id);
+
+ nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS);
+ if (nla_grps == NULL)
+ goto nla_put_failure;
+
+ nest = nla_nest_start(skb, 1);
+ if (nest == NULL)
+ goto nla_put_failure;
+
+ NLA_PUT_U32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id);
+ NLA_PUT_STRING(skb, CTRL_ATTR_MCAST_GRP_NAME,
+ grp->name);
+
+ nla_nest_end(skb, nest);
+ nla_nest_end(skb, nla_grps);
+
return genlmsg_end(skb, hdr);
nla_put_failure:
@@ -453,8 +637,8 @@ errout:
return skb->len;
}
-static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
- int seq, u8 cmd)
+static struct sk_buff *ctrl_build_family_msg(struct genl_family *family,
+ u32 pid, int seq, u8 cmd)
{
struct sk_buff *skb;
int err;
@@ -472,6 +656,25 @@ static struct sk_buff *ctrl_build_msg(struct genl_family *family, u32 pid,
return skb;
}
+static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp,
+ u32 pid, int seq, u8 cmd)
+{
+ struct sk_buff *skb;
+ int err;
+
+ skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+ if (skb == NULL)
+ return ERR_PTR(-ENOBUFS);
+
+ err = ctrl_fill_mcgrp_info(grp, pid, seq, 0, skb, cmd);
+ if (err < 0) {
+ nlmsg_free(skb);
+ return ERR_PTR(err);
+ }
+
+ return skb;
+}
+
static const struct nla_policy ctrl_policy[CTRL_ATTR_MAX+1] = {
[CTRL_ATTR_FAMILY_ID] = { .type = NLA_U16 },
[CTRL_ATTR_FAMILY_NAME] = { .type = NLA_NUL_STRING,
@@ -501,8 +704,8 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
goto errout;
}
- msg = ctrl_build_msg(res, info->snd_pid, info->snd_seq,
- CTRL_CMD_NEWFAMILY);
+ msg = ctrl_build_family_msg(res, info->snd_pid, info->snd_seq,
+ CTRL_CMD_NEWFAMILY);
if (IS_ERR(msg)) {
err = PTR_ERR(msg);
goto errout;
@@ -523,7 +726,15 @@ static int genl_ctrl_event(int event, void *data)
switch (event) {
case CTRL_CMD_NEWFAMILY:
case CTRL_CMD_DELFAMILY:
- msg = ctrl_build_msg(data, 0, 0, event);
+ msg = ctrl_build_family_msg(data, 0, 0, event);
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
+ break;
+ case CTRL_CMD_NEWMCAST_GRP:
+ case CTRL_CMD_DELMCAST_GRP:
+ msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
if (IS_ERR(msg))
return PTR_ERR(msg);
@@ -541,6 +752,10 @@ static struct genl_ops genl_ctrl_ops = {
.policy = ctrl_policy,
};
+static struct genl_multicast_group notify_grp = {
+ .name = "notify",
+};
+
static int __init genl_init(void)
{
int i, err;
@@ -557,11 +772,17 @@ static int __init genl_init(void)
goto errout_register;
netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
- genl_sock = netlink_kernel_create(NETLINK_GENERIC, GENL_MAX_ID,
- genl_rcv, NULL, THIS_MODULE);
+
+ /* we'll bump the group number right afterwards */
+ genl_sock = netlink_kernel_create(NETLINK_GENERIC, 0, genl_rcv,
+ NULL, THIS_MODULE);
if (genl_sock == NULL)
panic("GENL: Cannot initialize generic netlink\n");
+ err = genl_register_mc_group(&genl_ctrl, &notify_grp);
+ if (err < 0)
+ goto errout_register;
+
return 0;
errout_register:
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-16 11:39:42 +0000