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genetlink.c
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// SPDX-License-Identifier: GPL-2.0
/*
* NETLINK Generic Netlink Family
*
* Authors: Jamal Hadi Salim
* Thomas Graf <[email protected]>
* Johannes Berg <[email protected]>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/mutex.h>
#include <linux/bitmap.h>
#include <linux/rwsem.h>
#include <linux/idr.h>
#include <net/sock.h>
#include <net/genetlink.h>
static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
static DECLARE_RWSEM(cb_lock);
atomic_t genl_sk_destructing_cnt = ATOMIC_INIT(0);
DECLARE_WAIT_QUEUE_HEAD(genl_sk_destructing_waitq);
void genl_lock(void)
{
mutex_lock(&genl_mutex);
}
EXPORT_SYMBOL(genl_lock);
void genl_unlock(void)
{
mutex_unlock(&genl_mutex);
}
EXPORT_SYMBOL(genl_unlock);
static void genl_lock_all(void)
{
down_write(&cb_lock);
genl_lock();
}
static void genl_unlock_all(void)
{
genl_unlock();
up_write(&cb_lock);
}
static DEFINE_IDR(genl_fam_idr);
/*
* 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.
* Bit 1 is marked as already used since the drop-monitor code
* abuses the API and thinks it can statically use group 1.
* That group will typically conflict with other groups that
* any proper users use.
* Bit 16 is marked as used since it's used for generic netlink
* and the code no longer marks pre-reserved IDs as used.
* Bit 17 is marked as already used since the VFS quota code
* also abused this API and relied on family == group ID, we
* cater to that by giving it a static family and group ID.
* Bit 18 is marked as already used since the PMCRAID driver
* did the same thing as the VFS quota code (maybe copied?)
*/
static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) |
BIT(GENL_ID_VFS_DQUOT) |
BIT(GENL_ID_PMCRAID);
static unsigned long *mc_groups = &mc_group_start;
static unsigned long mc_groups_longs = 1;
static int genl_ctrl_event(int event, const struct genl_family *family,
const struct genl_multicast_group *grp,
int grp_id);
static const struct genl_family *genl_family_find_byid(unsigned int id)
{
return idr_find(&genl_fam_idr, id);
}
static const struct genl_family *genl_family_find_byname(char *name)
{
const struct genl_family *family;
unsigned int id;
idr_for_each_entry(&genl_fam_idr, family, id)
if (strcmp(family->name, name) == 0)
return family;
return NULL;
}
static int genl_get_cmd_cnt(const struct genl_family *family)
{
return family->n_ops + family->n_small_ops;
}
static void genl_op_from_full(const struct genl_family *family,
unsigned int i, struct genl_ops *op)
{
*op = family->ops[i];
if (!op->maxattr)
op->maxattr = family->maxattr;
if (!op->policy)
op->policy = family->policy;
}
static int genl_get_cmd_full(u32 cmd, const struct genl_family *family,
struct genl_ops *op)
{
int i;
for (i = 0; i < family->n_ops; i++)
if (family->ops[i].cmd == cmd) {
genl_op_from_full(family, i, op);
return 0;
}
return -ENOENT;
}
static void genl_op_from_small(const struct genl_family *family,
unsigned int i, struct genl_ops *op)
{
memset(op, 0, sizeof(*op));
op->doit = family->small_ops[i].doit;
op->dumpit = family->small_ops[i].dumpit;
op->cmd = family->small_ops[i].cmd;
op->internal_flags = family->small_ops[i].internal_flags;
op->flags = family->small_ops[i].flags;
op->validate = family->small_ops[i].validate;
op->maxattr = family->maxattr;
op->policy = family->policy;
}
static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
struct genl_ops *op)
{
int i;
for (i = 0; i < family->n_small_ops; i++)
if (family->small_ops[i].cmd == cmd) {
genl_op_from_small(family, i, op);
return 0;
}
return -ENOENT;
}
static int genl_get_cmd(u32 cmd, const struct genl_family *family,
struct genl_ops *op)
{
if (!genl_get_cmd_full(cmd, family, op))
return 0;
return genl_get_cmd_small(cmd, family, op);
}
static void genl_get_cmd_by_index(unsigned int i,
const struct genl_family *family,
struct genl_ops *op)
{
if (i < family->n_ops)
genl_op_from_full(family, i, op);
else if (i < family->n_ops + family->n_small_ops)
genl_op_from_small(family, i - family->n_ops, op);
else
WARN_ON_ONCE(1);
}
static int genl_allocate_reserve_groups(int n_groups, int *first_id)
{
unsigned long *new_groups;
int start = 0;
int i;
int id;
bool fits;
do {
if (start == 0)
id = find_first_zero_bit(mc_groups,
mc_groups_longs *
BITS_PER_LONG);
else
id = find_next_zero_bit(mc_groups,
mc_groups_longs * BITS_PER_LONG,
start);
fits = true;
for (i = id;
i < min_t(int, id + n_groups,
mc_groups_longs * BITS_PER_LONG);
i++) {
if (test_bit(i, mc_groups)) {
start = i;
fits = false;
break;
}
}
if (id + n_groups > mc_groups_longs * BITS_PER_LONG) {
unsigned long new_longs = mc_groups_longs +
BITS_TO_LONGS(n_groups);
size_t nlen = new_longs * sizeof(unsigned long);
if (mc_groups == &mc_group_start) {
new_groups = kzalloc(nlen, GFP_KERNEL);
if (!new_groups)
return -ENOMEM;
mc_groups = new_groups;
*mc_groups = mc_group_start;
} else {
new_groups = krealloc(mc_groups, nlen,
GFP_KERNEL);
if (!new_groups)
return -ENOMEM;
mc_groups = new_groups;
for (i = 0; i < BITS_TO_LONGS(n_groups); i++)
mc_groups[mc_groups_longs + i] = 0;
}
mc_groups_longs = new_longs;
}
} while (!fits);
for (i = id; i < id + n_groups; i++)
set_bit(i, mc_groups);
*first_id = id;
return 0;
}
static struct genl_family genl_ctrl;
static int genl_validate_assign_mc_groups(struct genl_family *family)
{
int first_id;
int n_groups = family->n_mcgrps;
int err = 0, i;
bool groups_allocated = false;
if (!n_groups)
return 0;
for (i = 0; i < n_groups; i++) {
const struct genl_multicast_group *grp = &family->mcgrps[i];
if (WARN_ON(grp->name[0] == '\0'))
return -EINVAL;
if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL))
return -EINVAL;
}
/* special-case our own group and hacks */
if (family == &genl_ctrl) {
first_id = GENL_ID_CTRL;
BUG_ON(n_groups != 1);
} else if (strcmp(family->name, "NET_DM") == 0) {
first_id = 1;
BUG_ON(n_groups != 1);
} else if (family->id == GENL_ID_VFS_DQUOT) {
first_id = GENL_ID_VFS_DQUOT;
BUG_ON(n_groups != 1);
} else if (family->id == GENL_ID_PMCRAID) {
first_id = GENL_ID_PMCRAID;
BUG_ON(n_groups != 1);
} else {
groups_allocated = true;
err = genl_allocate_reserve_groups(n_groups, &first_id);
if (err)
return err;
}
family->mcgrp_offset = first_id;
/* if still initializing, can't and don't need to realloc bitmaps */
if (!init_net.genl_sock)
return 0;
if (family->netnsok) {
struct net *net;
netlink_table_grab();
rcu_read_lock();
for_each_net_rcu(net) {
err = __netlink_change_ngroups(net->genl_sock,
mc_groups_longs * BITS_PER_LONG);
if (err) {
/*
* No need to roll back, can only fail if
* memory allocation fails and then the
* number of _possible_ groups has been
* increased on some sockets which is ok.
*/
break;
}
}
rcu_read_unlock();
netlink_table_ungrab();
} else {
err = netlink_change_ngroups(init_net.genl_sock,
mc_groups_longs * BITS_PER_LONG);
}
if (groups_allocated && err) {
for (i = 0; i < family->n_mcgrps; i++)
clear_bit(family->mcgrp_offset + i, mc_groups);
}
return err;
}
static void genl_unregister_mc_groups(const struct genl_family *family)
{
struct net *net;
int i;
netlink_table_grab();
rcu_read_lock();
for_each_net_rcu(net) {
for (i = 0; i < family->n_mcgrps; i++)
__netlink_clear_multicast_users(
net->genl_sock, family->mcgrp_offset + i);
}
rcu_read_unlock();
netlink_table_ungrab();
for (i = 0; i < family->n_mcgrps; i++) {
int grp_id = family->mcgrp_offset + i;
if (grp_id != 1)
clear_bit(grp_id, mc_groups);
genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family,
&family->mcgrps[i], grp_id);
}
}
static int genl_validate_ops(const struct genl_family *family)
{
int i, j;
if (WARN_ON(family->n_ops && !family->ops) ||
WARN_ON(family->n_small_ops && !family->small_ops))
return -EINVAL;
for (i = 0; i < genl_get_cmd_cnt(family); i++) {
struct genl_ops op;
genl_get_cmd_by_index(i, family, &op);
if (op.dumpit == NULL && op.doit == NULL)
return -EINVAL;
for (j = i + 1; j < genl_get_cmd_cnt(family); j++) {
struct genl_ops op2;
genl_get_cmd_by_index(j, family, &op2);
if (op.cmd == op2.cmd)
return -EINVAL;
}
}
return 0;
}
/**
* genl_register_family - register a generic netlink family
* @family: generic netlink family
*
* Registers the specified family after validating it first. Only one
* family may be registered with the same family name or identifier.
*
* The family's ops, multicast groups and module pointer must already
* be assigned.
*
* Return 0 on success or a negative error code.
*/
int genl_register_family(struct genl_family *family)
{
int err, i;
int start = GENL_START_ALLOC, end = GENL_MAX_ID;
err = genl_validate_ops(family);
if (err)
return err;
genl_lock_all();
if (genl_family_find_byname(family->name)) {
err = -EEXIST;
goto errout_locked;
}
/*
* Sadly, a few cases need to be special-cased
* due to them having previously abused the API
* and having used their family ID also as their
* multicast group ID, so we use reserved IDs
* for both to be sure we can do that mapping.
*/
if (family == &genl_ctrl) {
/* and this needs to be special for initial family lookups */
start = end = GENL_ID_CTRL;
} else if (strcmp(family->name, "pmcraid") == 0) {
start = end = GENL_ID_PMCRAID;
} else if (strcmp(family->name, "VFS_DQUOT") == 0) {
start = end = GENL_ID_VFS_DQUOT;
}
family->id = idr_alloc_cyclic(&genl_fam_idr, family,
start, end + 1, GFP_KERNEL);
if (family->id < 0) {
err = family->id;
goto errout_locked;
}
err = genl_validate_assign_mc_groups(family);
if (err)
goto errout_remove;
genl_unlock_all();
/* send all events */
genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0);
for (i = 0; i < family->n_mcgrps; i++)
genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family,
&family->mcgrps[i], family->mcgrp_offset + i);
return 0;
errout_remove:
idr_remove(&genl_fam_idr, family->id);
errout_locked:
genl_unlock_all();
return err;
}
EXPORT_SYMBOL(genl_register_family);
/**
* genl_unregister_family - unregister generic netlink family
* @family: generic netlink family
*
* Unregisters the specified family.
*
* Returns 0 on success or a negative error code.
*/
int genl_unregister_family(const struct genl_family *family)
{
genl_lock_all();
if (!genl_family_find_byid(family->id)) {
genl_unlock_all();
return -ENOENT;
}
genl_unregister_mc_groups(family);
idr_remove(&genl_fam_idr, family->id);
up_write(&cb_lock);
wait_event(genl_sk_destructing_waitq,
atomic_read(&genl_sk_destructing_cnt) == 0);
genl_unlock();
genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0);
return 0;
}
EXPORT_SYMBOL(genl_unregister_family);
/**
* genlmsg_put - Add generic netlink header to netlink message
* @skb: socket buffer holding the message
* @portid: netlink portid the message is addressed to
* @seq: sequence number (usually the one of the sender)
* @family: generic netlink family
* @flags: netlink message flags
* @cmd: generic netlink command
*
* Returns pointer to user specific header
*/
void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
const struct genl_family *family, int flags, u8 cmd)
{
struct nlmsghdr *nlh;
struct genlmsghdr *hdr;
nlh = nlmsg_put(skb, portid, seq, family->id, GENL_HDRLEN +
family->hdrsize, flags);
if (nlh == NULL)
return NULL;
hdr = nlmsg_data(nlh);
hdr->cmd = cmd;
hdr->version = family->version;
hdr->reserved = 0;
return (char *) hdr + GENL_HDRLEN;
}
EXPORT_SYMBOL(genlmsg_put);
static struct genl_dumpit_info *genl_dumpit_info_alloc(void)
{
return kmalloc(sizeof(struct genl_dumpit_info), GFP_KERNEL);
}
static void genl_dumpit_info_free(const struct genl_dumpit_info *info)
{
kfree(info);
}
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,
int hdrlen,
enum genl_validate_flags no_strict_flag)
{
enum netlink_validation validate = ops->validate & no_strict_flag ?
NL_VALIDATE_LIBERAL :
NL_VALIDATE_STRICT;
struct nlattr **attrbuf;
int err;
if (!ops->maxattr)
return NULL;
attrbuf = kmalloc_array(ops->maxattr + 1,
sizeof(struct nlattr *), GFP_KERNEL);
if (!attrbuf)
return ERR_PTR(-ENOMEM);
err = __nlmsg_parse(nlh, hdrlen, attrbuf, ops->maxattr, ops->policy,
validate, extack);
if (err) {
kfree(attrbuf);
return ERR_PTR(err);
}
return attrbuf;
}
static void genl_family_rcv_msg_attrs_free(struct nlattr **attrbuf)
{
kfree(attrbuf);
}
struct genl_start_context {
const struct genl_family *family;
struct nlmsghdr *nlh;
struct netlink_ext_ack *extack;
const struct genl_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;
struct genl_dumpit_info *info;
struct nlattr **attrs = NULL;
int rc = 0;
if (ops->validate & GENL_DONT_VALIDATE_DUMP)
goto no_attrs;
if (ctx->nlh->nlmsg_len < nlmsg_msg_size(ctx->hdrlen))
return -EINVAL;
attrs = genl_family_rcv_msg_attrs_parse(ctx->family, ctx->nlh, ctx->extack,
ops, ctx->hdrlen,
GENL_DONT_VALIDATE_DUMP_STRICT);
if (IS_ERR(attrs))
return PTR_ERR(attrs);
no_attrs:
info = genl_dumpit_info_alloc();
if (!info) {
genl_family_rcv_msg_attrs_free(attrs);
return -ENOMEM;
}
info->family = ctx->family;
info->op = *ops;
info->attrs = attrs;
cb->data = info;
if (ops->start) {
if (!ctx->family->parallel_ops)
genl_lock();
rc = ops->start(cb);
if (!ctx->family->parallel_ops)
genl_unlock();
}
if (rc) {
genl_family_rcv_msg_attrs_free(info->attrs);
genl_dumpit_info_free(info);
cb->data = NULL;
}
return rc;
}
static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
const struct genl_ops *ops = &genl_dumpit_info(cb)->op;
int rc;
genl_lock();
rc = ops->dumpit(skb, cb);
genl_unlock();
return rc;
}
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;
int rc = 0;
if (ops->done) {
genl_lock();
rc = ops->done(cb);
genl_unlock();
}
genl_family_rcv_msg_attrs_free(info->attrs);
genl_dumpit_info_free(info);
return rc;
}
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;
int rc = 0;
if (ops->done)
rc = ops->done(cb);
genl_family_rcv_msg_attrs_free(info->attrs);
genl_dumpit_info_free(info);
return rc;
}
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,
int hdrlen, struct net *net)
{
struct genl_start_context ctx;
int err;
if (!ops->dumpit)
return -EOPNOTSUPP;
ctx.family = family;
ctx.nlh = nlh;
ctx.extack = extack;
ctx.ops = ops;
ctx.hdrlen = hdrlen;
if (!family->parallel_ops) {
struct netlink_dump_control c = {
.module = family->module,
.data = &ctx,
.start = genl_start,
.dump = genl_lock_dumpit,
.done = genl_lock_done,
};
genl_unlock();
err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
genl_lock();
} else {
struct netlink_dump_control c = {
.module = family->module,
.data = &ctx,
.start = genl_start,
.dump = ops->dumpit,
.done = genl_parallel_done,
};
err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
}
return err;
}
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,
int hdrlen, struct net *net)
{
struct nlattr **attrbuf;
struct genl_info info;
int err;
if (!ops->doit)
return -EOPNOTSUPP;
attrbuf = genl_family_rcv_msg_attrs_parse(family, nlh, extack,
ops, hdrlen,
GENL_DONT_VALIDATE_STRICT);
if (IS_ERR(attrbuf))
return PTR_ERR(attrbuf);
info.snd_seq = nlh->nlmsg_seq;
info.snd_portid = NETLINK_CB(skb).portid;
info.nlhdr = nlh;
info.genlhdr = nlmsg_data(nlh);
info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
info.attrs = attrbuf;
info.extack = extack;
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 (err)
goto out;
}
err = ops->doit(skb, &info);
if (family->post_doit)
family->post_doit(ops, skb, &info);
out:
genl_family_rcv_msg_attrs_free(attrbuf);
return err;
}
static int genl_header_check(const struct genl_family *family,
struct nlmsghdr *nlh, struct genlmsghdr *hdr,
struct netlink_ext_ack *extack)
{
u16 flags;
/* Only for commands added after we started validating */
if (hdr->cmd < family->resv_start_op)
return 0;
if (hdr->reserved) {
NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0");
return -EINVAL;
}
/* Old netlink flags have pretty loose semantics, allow only the flags
* consumed by the core where we can enforce the meaning.
*/
flags = nlh->nlmsg_flags;
if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */
flags &= ~NLM_F_DUMP;
if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) {
NL_SET_ERR_MSG(extack,
"ambiguous or reserved bits set in nlmsg_flags");
return -EINVAL;
}
return 0;
}
static int genl_family_rcv_msg(const struct genl_family *family,
struct sk_buff *skb,
struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct genlmsghdr *hdr = nlmsg_data(nlh);
struct genl_ops op;
int hdrlen;
/* this family doesn't exist in this netns */
if (!family->netnsok && !net_eq(net, &init_net))
return -ENOENT;
hdrlen = GENL_HDRLEN + family->hdrsize;
if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
return -EINVAL;
if (genl_header_check(family, nlh, hdr, extack))
return -EINVAL;
if (genl_get_cmd(hdr->cmd, family, &op))
return -EOPNOTSUPP;
if ((op.flags & GENL_ADMIN_PERM) &&
!netlink_capable(skb, CAP_NET_ADMIN))
return -EPERM;
if ((op.flags & GENL_UNS_ADMIN_PERM) &&
!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
return -EPERM;
if ((nlh->nlmsg_flags & NLM_F_DUMP) == NLM_F_DUMP)
return genl_family_rcv_msg_dumpit(family, skb, nlh, extack,
&op, hdrlen, net);
else
return genl_family_rcv_msg_doit(family, skb, nlh, extack,
&op, hdrlen, net);
}
static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
const struct genl_family *family;
int err;
family = genl_family_find_byid(nlh->nlmsg_type);
if (family == NULL)
return -ENOENT;
if (!family->parallel_ops)
genl_lock();
err = genl_family_rcv_msg(family, skb, nlh, extack);
if (!family->parallel_ops)
genl_unlock();
return err;
}
static void genl_rcv(struct sk_buff *skb)
{
down_read(&cb_lock);
netlink_rcv_skb(skb, &genl_rcv_msg);
up_read(&cb_lock);
}
/**************************************************************************
* Controller
**************************************************************************/
static struct genl_family genl_ctrl;
static int ctrl_fill_info(const struct genl_family *family, u32 portid, u32 seq,
u32 flags, struct sk_buff *skb, u8 cmd)
{
void *hdr;
hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
if (hdr == NULL)
return -1;
if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id) ||
nla_put_u32(skb, CTRL_ATTR_VERSION, family->version) ||
nla_put_u32(skb, CTRL_ATTR_HDRSIZE, family->hdrsize) ||
nla_put_u32(skb, CTRL_ATTR_MAXATTR, family->maxattr))
goto nla_put_failure;
if (genl_get_cmd_cnt(family)) {
struct nlattr *nla_ops;
int i;
nla_ops = nla_nest_start_noflag(skb, CTRL_ATTR_OPS);
if (nla_ops == NULL)
goto nla_put_failure;
for (i = 0; i < genl_get_cmd_cnt(family); i++) {
struct nlattr *nest;
struct genl_ops op;
u32 op_flags;
genl_get_cmd_by_index(i, family, &op);
op_flags = op.flags;
if (op.dumpit)
op_flags |= GENL_CMD_CAP_DUMP;
if (op.doit)
op_flags |= GENL_CMD_CAP_DO;
if (op.policy)
op_flags |= GENL_CMD_CAP_HASPOL;
nest = nla_nest_start_noflag(skb, i + 1);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, CTRL_ATTR_OP_ID, op.cmd) ||
nla_put_u32(skb, CTRL_ATTR_OP_FLAGS, op_flags))
goto nla_put_failure;
nla_nest_end(skb, nest);
}
nla_nest_end(skb, nla_ops);
}
if (family->n_mcgrps) {
struct nlattr *nla_grps;
int i;
nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
if (nla_grps == NULL)
goto nla_put_failure;
for (i = 0; i < family->n_mcgrps; i++) {
struct nlattr *nest;
const struct genl_multicast_group *grp;
grp = &family->mcgrps[i];
nest = nla_nest_start_noflag(skb, i + 1);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID,
family->mcgrp_offset + i) ||
nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
grp->name))
goto nla_put_failure;
nla_nest_end(skb, nest);
}
nla_nest_end(skb, nla_grps);
}
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int ctrl_fill_mcgrp_info(const struct genl_family *family,
const struct genl_multicast_group *grp,
int grp_id, u32 portid, u32 seq, u32 flags,
struct sk_buff *skb, u8 cmd)
{
void *hdr;
struct nlattr *nla_grps;
struct nlattr *nest;
hdr = genlmsg_put(skb, portid, seq, &genl_ctrl, flags, cmd);
if (hdr == NULL)
return -1;
if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) ||
nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id))
goto nla_put_failure;
nla_grps = nla_nest_start_noflag(skb, CTRL_ATTR_MCAST_GROUPS);
if (nla_grps == NULL)
goto nla_put_failure;
nest = nla_nest_start_noflag(skb, 1);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) ||
nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME,
grp->name))
goto nla_put_failure;
nla_nest_end(skb, nest);
nla_nest_end(skb, nla_grps);
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
{
int n = 0;
struct genl_family *rt;
struct net *net = sock_net(skb->sk);
int fams_to_skip = cb->args[0];
unsigned int id;
idr_for_each_entry(&genl_fam_idr, rt, id) {
if (!rt->netnsok && !net_eq(net, &init_net))
continue;
if (n++ < fams_to_skip)
continue;
if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
skb, CTRL_CMD_NEWFAMILY) < 0) {
n--;
break;
}
}
cb->args[0] = n;
return skb->len;