On Thu, 2009-06-18 at 01:41 +0200, Johannes Berg wrote:
> On Wed, 2009-06-17 at 16:24 -0700, Eric W. Biederman wrote:
>
> > > So it looks like I can also use rcu_read_lock(), but there's no
> > > for_each_net_rcu(), should there be?
> >
> > I'm not using rcu safe list manipulation. What makes it look like
> > rcu_read_lock() is safe?
>
> Indeed. I was looking at rcu_barrier() only. How about the patch below?
With that, my genl patch can look like this:
Subject: genetlink: make netns aware
This makes generic netlink network namespace aware.
No actual generic netlink families are made namespace
aware, they need to be checked one by one and then
set the family->netnsok member to true.
Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
fs/dlm/netlink.c | 2
include/net/genetlink.h | 32 +++++--
include/net/net_namespace.h | 2
kernel/taskstats.c | 10 +-
net/irda/irnetlink.c | 2
net/netfilter/ipvs/ip_vs_ctl.c | 2
net/netlink/genetlink.c | 184 +++++++++++++++++++++++++++++++++--------
net/tipc/netlink.c | 2
net/wireless/nl80211.c | 14 +--
9 files changed, 191 insertions(+), 59 deletions(-)
--- wireless-testing.orig/include/net/genetlink.h 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/include/net/genetlink.h 2009-06-18 01:41:51.000000000 +0200
@@ -3,6 +3,7 @@
#include <linux/genetlink.h>
#include <net/netlink.h>
+#include <net/net_namespace.h>
/**
* struct genl_multicast_group - generic netlink multicast group
@@ -27,6 +28,8 @@ struct genl_multicast_group
* @name: name of family
* @version: protocol version
* @maxattr: maximum number of attributes supported
+ * @netnsok: set to true if the family can handle network
+ * namespaces and should be presented in all of them
* @attrbuf: buffer to store parsed attributes
* @ops_list: list of all assigned operations
* @family_list: family list
@@ -39,6 +42,7 @@ struct genl_family
char name[GENL_NAMSIZ];
unsigned int version;
unsigned int maxattr;
+ bool netnsok;
struct nlattr ** attrbuf; /* private */
struct list_head ops_list; /* private */
struct list_head family_list; /* private */
@@ -62,6 +66,7 @@ struct genl_info
struct genlmsghdr * genlhdr;
void * userhdr;
struct nlattr ** attrs;
+ struct net * net;
};
/**
@@ -96,8 +101,6 @@ extern int genl_register_mc_group(struct
extern void genl_unregister_mc_group(struct genl_family *family,
struct genl_multicast_group *grp);
-extern struct sock *genl_sock;
-
/**
* genlmsg_put - Add generic netlink header to netlink message
* @skb: socket buffer holding the message
@@ -168,16 +171,27 @@ static inline void genlmsg_cancel(struct
}
/**
- * genlmsg_multicast - multicast a netlink message
+ * genlmsg_multicast - multicast a netlink message to all network namespaces
+ * @skb: netlink message as socket buffer
+ * @pid: own netlink pid to avoid sending to yourself
+ * @group: multicast group id
+ * @flags: allocation flags
+ */
+int genlmsg_multicast(struct sk_buff *skb, u32 pid,
+ unsigned int group, gfp_t flags);
+
+/**
+ * genlmsg_multicast_netns - multicast a netlink message to a specific netns
+ * @net: the net namespace
* @skb: netlink message as socket buffer
* @pid: own netlink pid to avoid sending to yourself
* @group: multicast group id
* @flags: allocation flags
*/
-static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,
- unsigned int group, gfp_t flags)
+static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
+ u32 pid, unsigned int group, gfp_t flags)
{
- return nlmsg_multicast(genl_sock, skb, pid, group, flags);
+ return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
}
/**
@@ -185,9 +199,9 @@ static inline int genlmsg_multicast(stru
* @skb: netlink message as socket buffer
* @pid: netlink pid of the destination socket
*/
-static inline int genlmsg_unicast(struct sk_buff *skb, u32 pid)
+static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid)
{
- return nlmsg_unicast(genl_sock, skb, pid);
+ return nlmsg_unicast(net->genl_sock, skb, pid);
}
/**
@@ -197,7 +211,7 @@ static inline int genlmsg_unicast(struct
*/
static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
{
- return genlmsg_unicast(skb, info->snd_pid);
+ return genlmsg_unicast(info->net, skb, info->snd_pid);
}
/**
--- wireless-testing.orig/net/netlink/genetlink.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/net/netlink/genetlink.c 2009-06-18 01:41:51.000000000 +0200
@@ -15,11 +15,10 @@
#include <linux/skbuff.h>
#include <linux/mutex.h>
#include <linux/bitmap.h>
+#include <linux/rtnetlink.h>
#include <net/sock.h>
#include <net/genetlink.h>
-struct sock *genl_sock = NULL;
-
static DEFINE_MUTEX(genl_mutex); /* serialization of message processing */
static inline void genl_lock(void)
@@ -175,10 +174,30 @@ int genl_register_mc_group(struct genl_f
mc_groups_longs++;
}
- err = netlink_change_ngroups(genl_sock,
- mc_groups_longs * BITS_PER_LONG);
- if (err)
- goto out;
+ if (family->netnsok) {
+ struct net *net;
+
+ rtnl_lock();
+ for_each_net(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 groups is larger for
+ * some sockets which is ok.
+ */
+ goto out;
+ }
+ }
+ rtnl_unlock();
+ } else {
+ err = netlink_change_ngroups(init_net.genl_sock,
+ mc_groups_longs * BITS_PER_LONG);
+ if (err)
+ goto out;
+ }
grp->id = id;
set_bit(id, mc_groups);
@@ -195,8 +214,14 @@ EXPORT_SYMBOL(genl_register_mc_group);
static void __genl_unregister_mc_group(struct genl_family *family,
struct genl_multicast_group *grp)
{
+ struct net *net;
BUG_ON(grp->family != family);
- netlink_clear_multicast_users(genl_sock, grp->id);
+
+ rtnl_lock();
+ for_each_net(net)
+ netlink_clear_multicast_users(net->genl_sock, grp->id);
+ rtnl_unlock();
+
clear_bit(grp->id, mc_groups);
list_del(&grp->list);
genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp);
@@ -421,6 +446,7 @@ static int genl_rcv_msg(struct sk_buff *
{
struct genl_ops *ops;
struct genl_family *family;
+ struct net *net = sock_net(skb->sk);
struct genl_info info;
struct genlmsghdr *hdr = nlmsg_data(nlh);
int hdrlen, err;
@@ -429,6 +455,10 @@ static int genl_rcv_msg(struct sk_buff *
if (family == NULL)
return -ENOENT;
+ /* this family doesn't exist in this netns */
+ if (!family->netnsok && net != &init_net)
+ return -ENOENT;
+
hdrlen = GENL_HDRLEN + family->hdrsize;
if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
return -EINVAL;
@@ -446,7 +476,7 @@ static int genl_rcv_msg(struct sk_buff *
return -EOPNOTSUPP;
genl_unlock();
- err = netlink_dump_start(genl_sock, skb, nlh,
+ err = netlink_dump_start(net->genl_sock, skb, nlh,
ops->dumpit, ops->done);
genl_lock();
return err;
@@ -468,6 +498,7 @@ static int genl_rcv_msg(struct sk_buff *
info.genlhdr = nlmsg_data(nlh);
info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
info.attrs = family->attrbuf;
+ info.net = net;
return ops->doit(skb, &info);
}
@@ -488,6 +519,7 @@ static struct genl_family genl_ctrl = {
.name = "nlctrl",
.version = 0x2,
.maxattr = CTRL_ATTR_MAX,
+ .netnsok = true,
};
static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
@@ -604,6 +636,7 @@ static int ctrl_dumpfamily(struct sk_buf
int i, n = 0;
struct genl_family *rt;
+ struct net *net = sock_net(skb->sk);
int chains_to_skip = cb->args[0];
int fams_to_skip = cb->args[1];
@@ -612,6 +645,8 @@ static int ctrl_dumpfamily(struct sk_buf
continue;
n = 0;
list_for_each_entry(rt, genl_family_chain(i), family_list) {
+ if (!rt->netnsok && net != &init_net)
+ continue;
if (++n < fams_to_skip)
continue;
if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).pid,
@@ -683,6 +718,7 @@ static int ctrl_getfamily(struct sk_buff
if (info->attrs[CTRL_ATTR_FAMILY_ID]) {
u16 id = nla_get_u16(info->attrs[CTRL_ATTR_FAMILY_ID]);
res = genl_family_find_byid(id);
+ err = -ENOENT;
}
if (info->attrs[CTRL_ATTR_FAMILY_NAME]) {
@@ -690,51 +726,60 @@ static int ctrl_getfamily(struct sk_buff
name = nla_data(info->attrs[CTRL_ATTR_FAMILY_NAME]);
res = genl_family_find_byname(name);
+ err = -ENOENT;
}
- if (res == NULL) {
- err = -ENOENT;
- goto errout;
+ if (res == NULL)
+ return err;
+
+ if (!res->netnsok && info->net != &init_net) {
+ /* family doesn't exist here */
+ return -ENOENT;
}
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;
- }
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
- err = genlmsg_reply(msg, info);
-errout:
- return err;
+ return genlmsg_reply(msg, info);
}
static int genl_ctrl_event(int event, void *data)
{
struct sk_buff *msg;
+ struct genl_family *family;
+ struct genl_multicast_group *grp;
- if (genl_sock == NULL)
+ /* genl is still initialising */
+ if (!init_net.genl_sock)
return 0;
switch (event) {
case CTRL_CMD_NEWFAMILY:
case CTRL_CMD_DELFAMILY:
- 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);
+ family = data;
+ msg = ctrl_build_family_msg(family, 0, 0, event);
break;
case CTRL_CMD_NEWMCAST_GRP:
case CTRL_CMD_DELMCAST_GRP:
+ grp = data;
+ family = grp->family;
msg = ctrl_build_mcgrp_msg(data, 0, 0, event);
- if (IS_ERR(msg))
- return PTR_ERR(msg);
-
- genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
break;
+ default:
+ return -EINVAL;
}
+ if (IS_ERR(msg))
+ return PTR_ERR(msg);
+
+ if (!family->netnsok)
+ genlmsg_multicast_netns(&init_net, msg, 0,
+ GENL_ID_CTRL, GFP_KERNEL);
+ else
+ genlmsg_multicast(msg, 0, GENL_ID_CTRL, GFP_KERNEL);
+
return 0;
}
@@ -749,6 +794,33 @@ static struct genl_multicast_group notif
.name = "notify",
};
+static int __net_init genl_pernet_init(struct net *net)
+{
+ /* we'll bump the group number right afterwards */
+ net->genl_sock = netlink_kernel_create(net, NETLINK_GENERIC, 0,
+ genl_rcv, &genl_mutex,
+ THIS_MODULE);
+
+ if (!net->genl_sock && net == &init_net)
+ panic("GENL: Cannot initialize generic netlink\n");
+
+ if (!net->genl_sock)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __net_exit genl_pernet_exit(struct net *net)
+{
+ netlink_kernel_release(net->genl_sock);
+ net->genl_sock = NULL;
+}
+
+static struct pernet_operations genl_pernet_ops = {
+ .init = genl_pernet_init,
+ .exit = genl_pernet_exit,
+};
+
static int __init genl_init(void)
{
int i, err;
@@ -766,11 +838,9 @@ static int __init genl_init(void)
netlink_set_nonroot(NETLINK_GENERIC, NL_NONROOT_RECV);
- /* we'll bump the group number right afterwards */
- genl_sock = netlink_kernel_create(&init_net, NETLINK_GENERIC, 0,
- genl_rcv, &genl_mutex, THIS_MODULE);
- if (genl_sock == NULL)
- panic("GENL: Cannot initialize generic netlink\n");
+ err = register_pernet_subsys(&genl_pernet_ops);
+ if (err)
+ goto errout_register;
err = genl_register_mc_group(&genl_ctrl, ¬ify_grp);
if (err < 0)
@@ -786,8 +856,54 @@ errout:
subsys_initcall(genl_init);
-EXPORT_SYMBOL(genl_sock);
EXPORT_SYMBOL(genl_register_ops);
EXPORT_SYMBOL(genl_unregister_ops);
EXPORT_SYMBOL(genl_register_family);
EXPORT_SYMBOL(genl_unregister_family);
+
+static int genlmsg_mcast(struct sk_buff *skb, u32 pid, unsigned long group,
+ gfp_t flags)
+{
+ struct sk_buff *tmp;
+ struct net *net, *prev = NULL;
+ int err;
+
+ for_each_net_rcu(net) {
+ if (prev) {
+ tmp = skb_clone(skb, flags);
+ if (!tmp) {
+ err = -ENOMEM;
+ goto error;
+ }
+ err = nlmsg_multicast(prev->genl_sock, tmp,
+ pid, group, flags);
+ if (err)
+ goto error;
+ }
+
+ prev = net;
+ }
+
+ return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
+ error:
+ return err;
+}
+
+int genlmsg_multicast(struct sk_buff *skb, u32 pid,
+ unsigned int group, gfp_t flags)
+{
+ int ret;
+
+ if (flags & GFP_ATOMIC) {
+ rcu_read_lock();
+ ret = genlmsg_mcast(skb, pid, group, flags);
+ rcu_read_unlock();
+ } else {
+ rtnl_lock();
+ ret = genlmsg_mcast(skb, pid, group, flags);
+ rtnl_unlock();
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(genlmsg_multicast);
--- wireless-testing.orig/fs/dlm/netlink.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/fs/dlm/netlink.c 2009-06-18 01:41:51.000000000 +0200
@@ -63,7 +63,7 @@ static int send_data(struct sk_buff *skb
return rv;
}
- return genlmsg_unicast(skb, listener_nlpid);
+ return genlmsg_unicast(&init_net, skb, listener_nlpid);
}
static int user_cmd(struct sk_buff *skb, struct genl_info *info)
--- wireless-testing.orig/kernel/taskstats.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/kernel/taskstats.c 2009-06-18 01:41:51.000000000 +0200
@@ -108,7 +108,7 @@ static int prepare_reply(struct genl_inf
/*
* Send taskstats data in @skb to listener with nl_pid @pid
*/
-static int send_reply(struct sk_buff *skb, pid_t pid)
+static int send_reply(struct sk_buff *skb, struct genl_info *info)
{
struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
void *reply = genlmsg_data(genlhdr);
@@ -120,7 +120,7 @@ static int send_reply(struct sk_buff *sk
return rc;
}
- return genlmsg_unicast(skb, pid);
+ return genlmsg_reply(skb, info);
}
/*
@@ -150,7 +150,7 @@ static void send_cpu_listeners(struct sk
if (!skb_next)
break;
}
- rc = genlmsg_unicast(skb_cur, s->pid);
+ rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
if (rc == -ECONNREFUSED) {
s->valid = 0;
delcount++;
@@ -418,7 +418,7 @@ static int cgroupstats_user_cmd(struct s
goto err;
}
- rc = send_reply(rep_skb, info->snd_pid);
+ rc = send_reply(rep_skb, info);
err:
fput_light(file, fput_needed);
@@ -487,7 +487,7 @@ free_return_rc:
} else
goto err;
- return send_reply(rep_skb, info->snd_pid);
+ return send_reply(rep_skb, info);
err:
nlmsg_free(rep_skb);
return rc;
--- wireless-testing.orig/net/irda/irnetlink.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/net/irda/irnetlink.c 2009-06-18 01:41:51.000000000 +0200
@@ -115,7 +115,7 @@ static int irda_nl_get_mode(struct sk_bu
genlmsg_end(msg, hdr);
- return genlmsg_unicast(msg, info->snd_pid);
+ return genlmsg_reply(msg, info);
err_out:
nlmsg_free(msg);
--- wireless-testing.orig/net/netfilter/ipvs/ip_vs_ctl.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/net/netfilter/ipvs/ip_vs_ctl.c 2009-06-18 01:41:51.000000000 +0200
@@ -3231,7 +3231,7 @@ static int ip_vs_genl_get_cmd(struct sk_
}
genlmsg_end(msg, reply);
- ret = genlmsg_unicast(msg, info->snd_pid);
+ ret = genlmsg_reply(msg, info);
goto out;
nla_put_failure:
--- wireless-testing.orig/net/tipc/netlink.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/net/tipc/netlink.c 2009-06-18 01:41:51.000000000 +0200
@@ -62,7 +62,7 @@ static int handle_cmd(struct sk_buff *sk
rep_nlh = nlmsg_hdr(rep_buf);
memcpy(rep_nlh, req_nlh, hdr_space);
rep_nlh->nlmsg_len = rep_buf->len;
- genlmsg_unicast(rep_buf, NETLINK_CB(skb).pid);
+ genlmsg_unicast(&init_net, rep_buf, NETLINK_CB(skb).pid);
}
return 0;
--- wireless-testing.orig/net/wireless/nl80211.c 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/net/wireless/nl80211.c 2009-06-18 01:41:51.000000000 +0200
@@ -398,7 +398,7 @@ static int nl80211_get_wiphy(struct sk_b
cfg80211_put_dev(dev);
- return genlmsg_unicast(msg, info->snd_pid);
+ return genlmsg_reply(msg, info);
out_free:
nlmsg_free(msg);
@@ -723,7 +723,7 @@ static int nl80211_get_interface(struct
dev_put(netdev);
cfg80211_put_dev(dev);
- return genlmsg_unicast(msg, info->snd_pid);
+ return genlmsg_reply(msg, info);
out_free:
nlmsg_free(msg);
@@ -1014,7 +1014,7 @@ static int nl80211_get_key(struct sk_buf
goto nla_put_failure;
genlmsg_end(msg, hdr);
- err = genlmsg_unicast(msg, info->snd_pid);
+ err = genlmsg_reply(msg, info);
goto out;
nla_put_failure:
@@ -1602,7 +1602,7 @@ static int nl80211_get_station(struct sk
dev, mac_addr, &sinfo) < 0)
goto out_free;
- err = genlmsg_unicast(msg, info->snd_pid);
+ err = genlmsg_reply(msg, info);
goto out;
out_free:
@@ -2009,7 +2009,7 @@ static int nl80211_get_mpath(struct sk_b
dev, dst, next_hop, &pinfo) < 0)
goto out_free;
- err = genlmsg_unicast(msg, info->snd_pid);
+ err = genlmsg_reply(msg, info);
goto out;
out_free:
@@ -2358,7 +2358,7 @@ static int nl80211_get_mesh_params(struc
cur_params.dot11MeshHWMPnetDiameterTraversalTime);
nla_nest_end(msg, pinfoattr);
genlmsg_end(msg, hdr);
- err = genlmsg_unicast(msg, info->snd_pid);
+ err = genlmsg_reply(msg, info);
goto out;
nla_put_failure:
@@ -2546,7 +2546,7 @@ static int nl80211_get_reg(struct sk_buf
nla_nest_end(msg, nl_reg_rules);
genlmsg_end(msg, hdr);
- err = genlmsg_unicast(msg, info->snd_pid);
+ err = genlmsg_reply(msg, info);
goto out;
nla_put_failure:
--- wireless-testing.orig/include/net/net_namespace.h 2009-06-18 01:39:35.000000000 +0200
+++ wireless-testing/include/net/net_namespace.h 2009-06-18 01:41:51.000000000 +0200
@@ -26,6 +26,7 @@ struct net_device;
struct sock;
struct ctl_table_header;
struct net_generic;
+struct sock;
struct net {
atomic_t count; /* To decided when the network
@@ -63,6 +64,7 @@ struct net {
struct netns_packet packet;
struct netns_unix unx;
struct netns_ipv4 ipv4;
+ struct sock *genl_sock;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
struct netns_ipv6 ipv6;
#endif
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