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Subject[PATCH 4/5] ipv4: share sysctl net/ipv4/conf/DEVNAME/ tables
Date
Before this, for each network device DEVNAME that supports ipv4 a new
sysctl table was registered in $PROC/sys/net/ipv4/conf/DEVNAME/.

The sysctl table was identical for all network devices, except for:
* data: pointer to the data to be accessed in the sysctl
* extra1: the 'struct ipv4_devconf*' of the network device
* extra2: the 'struct net*' of the network namespace

Assuming we have a device name and a 'struct net*', we can get the
'struct net_device*'. From there we can compute:
* data: each entry corresponds to a position in 'struct ipv4_devconf*'
* extra1: 'struct ipv4_devconf*' can be reached from 'struct net_device*'
* extra2: the 'struct net*' that we assumed to have

The device name is determined from the path to the file (the name of
the parent dentry).

The 'struct net*' is stored in the parent 'struct ctl_table*' path by
register_net_sysctl_table_pathdata().

Signed-off-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
---
fs/proc/proc_sysctl.c | 16 +++-
include/linux/inetdevice.h | 12 +++-
net/ipv4/devinet.c | 203 +++++++++++++++++++++++++++++---------------
3 files changed, 161 insertions(+), 70 deletions(-)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index fb707e0..fe392f1 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -128,6 +128,11 @@ out:
return err;
}

+
+typedef int proc_handler_extended(struct ctl_table *ctl, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos,
+ struct file *filp);
+
static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
size_t count, loff_t *ppos, int write)
{
@@ -136,6 +141,7 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
ssize_t error;
size_t res;
+ proc_handler_extended *phx = (proc_handler_extended *) table->proc_handler;

if (IS_ERR(head))
return PTR_ERR(head);
@@ -155,7 +161,15 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,

/* careful: calling conventions are nasty here */
res = count;
- error = table->proc_handler(table, write, buf, &res, ppos);
+ /* Most handlers only use the first 5 arguments (without @filp).
+ * Changing all is too much of work, as, at the time of writting only
+ * the devinet.c proc_handlers know about and use the @filp.
+ *
+ * This is just a HACK for now, I did this this way to not
+ * waste time changing all the handlers, in the final version
+ * I'll change all the handlers if there's not other solution.
+ */
+ error = phx(table, write, buf, &res, ppos, filp);
if (!error)
error = res;
out:
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index ae8fdc5..caf06b3 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -43,8 +43,18 @@ enum

#define IPV4_DEVCONF_MAX (__IPV4_DEVCONF_MAX - 1)

+
+struct devinet_sysctl {
+ /* dev_name holds a copy of dev_name, because '.procname' is
+ * regarded as const by sysctl and we wouldn't want anyone to
+ * change it under our feet (see SIOCSIFNAME). */
+ char *dev_name;
+ struct ctl_table_header *sysctl_header;
+};
+
+
struct ipv4_devconf {
- void *sysctl;
+ struct devinet_sysctl devinet_sysctl;
int data[IPV4_DEVCONF_MAX];
DECLARE_BITMAP(state, IPV4_DEVCONF_MAX);
};
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 748cb5b..774d347 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -147,7 +147,7 @@ void in_dev_finish_destroy(struct in_device *idev)
}
EXPORT_SYMBOL(in_dev_finish_destroy);

-static struct in_device *inetdev_init(struct net_device *dev)
+struct in_device *inetdev_init(struct net_device *dev)
{
struct in_device *in_dev;

@@ -158,7 +158,8 @@ static struct in_device *inetdev_init(struct net_device *dev)
goto out;
memcpy(&in_dev->cnf, dev_net(dev)->ipv4.devconf_dflt,
sizeof(in_dev->cnf));
- in_dev->cnf.sysctl = NULL;
+ in_dev->cnf.devinet_sysctl.dev_name = NULL;
+ in_dev->cnf.devinet_sysctl.sysctl_header = NULL;
in_dev->dev = dev;
in_dev->arp_parms = neigh_parms_alloc(dev, &arp_tbl);
if (!in_dev->arp_parms)
@@ -1375,6 +1376,67 @@ static void inet_forward_change(struct net *net)
}
}

+
+
+static int devinet_conf_handler(ctl_table *ctl, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos,
+ struct file *filp,
+ proc_handler *proc_handler)
+{
+ /* The path to this file is of the form:
+ * $PROC_MOUNT/sys/net/ipv4/conf/$DEVNAME/$CTL
+ *
+ * The array of 'struct ctl_table' of devinet entries is
+ * shared between all ipv4 network devices and the 'data'
+ * field of each structure only hold the offset into the
+ * 'data' field of 'struct ipv4_devconf'.
+ *
+ * To find the propper location of the data that must be
+ * accessed by this handler we need the device name and the
+ * network namespace in which it belongs.
+ */
+
+ /* We store the network namespace in the parent table's ->extra2 */
+ struct inode *parent_inode = filp->f_path.dentry->d_parent->d_inode;
+ struct ctl_table *parent_table = PROC_I(parent_inode)->sysctl_entry;
+ struct net *net = parent_table->extra2;
+
+ const char *dev_name = filp->f_path.dentry->d_parent->d_name.name;
+ struct ctl_table tmp_ctl;
+ struct net_device *dev = NULL;
+ struct in_device *in_dev = NULL;
+ struct ipv4_devconf *cnf;
+ int ret;
+
+ if (strcmp(dev_name, "all") == 0) {
+ cnf = net->ipv4.devconf_all;
+ } else if (strcmp(dev_name, "default") == 0) {
+ cnf = net->ipv4.devconf_dflt;
+ } else {
+ /* the device could have been renamed (SIOCSIFADDR) or
+ * deleted since we started accessing it's proc sysctl */
+ dev = dev_get_by_name(net, dev_name);
+ if (dev == NULL)
+ return -ENOENT;
+ in_dev = in_dev_get(dev);
+ cnf = &in_dev->cnf;
+ }
+
+ tmp_ctl = *ctl;
+ tmp_ctl.data += (char *)cnf - (char *)&ipv4_devconf;
+ tmp_ctl.extra1 = cnf;
+ tmp_ctl.extra2 = net;
+
+ ret = proc_handler(&tmp_ctl, write, buffer, lenp, ppos);
+
+ if (in_dev)
+ in_dev_put(in_dev);
+ if (dev)
+ dev_put(dev);
+ return ret;
+}
+
static int devinet_conf_proc(ctl_table *ctl, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos)
@@ -1445,6 +1507,33 @@ static int ipv4_doint_and_flush(ctl_table *ctl, int write,
return ret;
}

+static int devinet_conf_proc__(ctl_table *ctl, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos,
+ struct file *filp)
+{
+ return devinet_conf_handler(ctl, write, buffer, lenp, ppos, filp,
+ devinet_conf_proc);
+}
+
+static int devinet_sysctl_forward__(ctl_table *ctl, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos,
+ struct file *filp)
+{
+ return devinet_conf_handler(ctl, write, buffer, lenp, ppos, filp,
+ devinet_sysctl_forward);
+}
+
+static int ipv4_doint_and_flush__(ctl_table *ctl, int write,
+ void __user *buffer,
+ size_t *lenp, loff_t *ppos,
+ struct file *filp)
+{
+ return devinet_conf_handler(ctl, write, buffer, lenp, ppos, filp,
+ ipv4_doint_and_flush);
+}
+
#define DEVINET_SYSCTL_ENTRY(attr, name, mval, proc) \
{ \
.procname = name, \
@@ -1452,67 +1541,60 @@ static int ipv4_doint_and_flush(ctl_table *ctl, int write,
IPV4_DEVCONF_ ## attr - 1, \
.maxlen = sizeof(int), \
.mode = mval, \
- .proc_handler = proc, \
- .extra1 = &ipv4_devconf, \
+ .proc_handler = (proc_handler *) proc, \
}

#define DEVINET_SYSCTL_RW_ENTRY(attr, name) \
- DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc)
+ DEVINET_SYSCTL_ENTRY(attr, name, 0644, devinet_conf_proc__)

#define DEVINET_SYSCTL_RO_ENTRY(attr, name) \
- DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc)
+ DEVINET_SYSCTL_ENTRY(attr, name, 0444, devinet_conf_proc__)

#define DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, proc) \
DEVINET_SYSCTL_ENTRY(attr, name, 0644, proc)

#define DEVINET_SYSCTL_FLUSHING_ENTRY(attr, name) \
- DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush)
-
-static struct devinet_sysctl_table {
- struct ctl_table_header *sysctl_header;
- struct ctl_table devinet_vars[__IPV4_DEVCONF_MAX];
- char *dev_name;
-} devinet_sysctl = {
- .devinet_vars = {
- DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
- devinet_sysctl_forward),
- DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
-
- DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
- DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
- DEVINET_SYSCTL_RW_ENTRY(SHARED_MEDIA, "shared_media"),
- DEVINET_SYSCTL_RW_ENTRY(RP_FILTER, "rp_filter"),
- DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
- DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
- "accept_source_route"),
- DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
- DEVINET_SYSCTL_RW_ENTRY(SRC_VMARK, "src_valid_mark"),
- DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
- DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
- DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
- DEVINET_SYSCTL_RW_ENTRY(LOG_MARTIANS, "log_martians"),
- DEVINET_SYSCTL_RW_ENTRY(TAG, "tag"),
- DEVINET_SYSCTL_RW_ENTRY(ARPFILTER, "arp_filter"),
- DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
- DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
- DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
- DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
- DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"),
-
- DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
- DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
- DEVINET_SYSCTL_FLUSHING_ENTRY(FORCE_IGMP_VERSION,
- "force_igmp_version"),
- DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES,
- "promote_secondaries"),
- },
+ DEVINET_SYSCTL_COMPLEX_ENTRY(attr, name, ipv4_doint_and_flush__)
+
+const struct ctl_table ipv4_devinet_sysctl_table[__IPV4_DEVCONF_MAX] = {
+ DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
+ devinet_sysctl_forward__),
+ DEVINET_SYSCTL_RO_ENTRY(MC_FORWARDING, "mc_forwarding"),
+
+ DEVINET_SYSCTL_RW_ENTRY(ACCEPT_REDIRECTS, "accept_redirects"),
+ DEVINET_SYSCTL_RW_ENTRY(SECURE_REDIRECTS, "secure_redirects"),
+ DEVINET_SYSCTL_RW_ENTRY(SHARED_MEDIA, "shared_media"),
+ DEVINET_SYSCTL_RW_ENTRY(RP_FILTER, "rp_filter"),
+ DEVINET_SYSCTL_RW_ENTRY(SEND_REDIRECTS, "send_redirects"),
+ DEVINET_SYSCTL_RW_ENTRY(ACCEPT_SOURCE_ROUTE,
+ "accept_source_route"),
+ DEVINET_SYSCTL_RW_ENTRY(ACCEPT_LOCAL, "accept_local"),
+ DEVINET_SYSCTL_RW_ENTRY(SRC_VMARK, "src_valid_mark"),
+ DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP, "proxy_arp"),
+ DEVINET_SYSCTL_RW_ENTRY(MEDIUM_ID, "medium_id"),
+ DEVINET_SYSCTL_RW_ENTRY(BOOTP_RELAY, "bootp_relay"),
+ DEVINET_SYSCTL_RW_ENTRY(LOG_MARTIANS, "log_martians"),
+ DEVINET_SYSCTL_RW_ENTRY(TAG, "tag"),
+ DEVINET_SYSCTL_RW_ENTRY(ARPFILTER, "arp_filter"),
+ DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
+ DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
+ DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
+ DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
+ DEVINET_SYSCTL_RW_ENTRY(PROXY_ARP_PVLAN, "proxy_arp_pvlan"),
+
+ DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
+ DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
+ DEVINET_SYSCTL_FLUSHING_ENTRY(FORCE_IGMP_VERSION,
+ "force_igmp_version"),
+ DEVINET_SYSCTL_FLUSHING_ENTRY(PROMOTE_SECONDARIES,
+ "promote_secondaries"),
+ { }
};

static int __devinet_sysctl_register(struct net *net, char *dev_name,
- struct ipv4_devconf *p)
+ struct ipv4_devconf *cnf)
{
- int i;
- struct devinet_sysctl_table *t;
+ struct devinet_sysctl *t = &cnf->devinet_sysctl;

#define DEVINET_CTL_PATH_DEV 3

@@ -1524,16 +1606,6 @@ static int __devinet_sysctl_register(struct net *net, char *dev_name,
{ },
};

- t = kmemdup(&devinet_sysctl, sizeof(*t), GFP_KERNEL);
- if (!t)
- goto out;
-
- for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
- t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
- t->devinet_vars[i].extra1 = p;
- t->devinet_vars[i].extra2 = net;
- }
-
/*
* Make a copy of dev_name, because '.procname' is regarded as const
* by sysctl and we wouldn't want anyone to change it under our feet
@@ -1541,37 +1613,32 @@ static int __devinet_sysctl_register(struct net *net, char *dev_name,
*/
t->dev_name = kstrdup(dev_name, GFP_KERNEL);
if (!t->dev_name)
- goto free;
+ goto out;

devinet_ctl_path[DEVINET_CTL_PATH_DEV].procname = t->dev_name;

- t->sysctl_header = register_net_sysctl_table(net, devinet_ctl_path,
- t->devinet_vars);
+ t->sysctl_header = register_net_sysctl_table_pathdata(net,
+ devinet_ctl_path, ipv4_devinet_sysctl_table, net);
if (!t->sysctl_header)
goto free_procname;

- p->sysctl = t;
return 0;

free_procname:
kfree(t->dev_name);
-free:
- kfree(t);
out:
return -ENOBUFS;
}

static void __devinet_sysctl_unregister(struct ipv4_devconf *cnf)
{
- struct devinet_sysctl_table *t = cnf->sysctl;
+ struct devinet_sysctl *t = &cnf->devinet_sysctl;

if (t == NULL)
return;

- cnf->sysctl = NULL;
unregister_sysctl_table(t->sysctl_header);
kfree(t->dev_name);
- kfree(t);
}

static void devinet_sysctl_register(struct in_device *idev)
--
1.7.4.rc1.7.g2cf08.dirty


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