Patchwork [05/11] Phonet: Netlink interface

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Submitter Rémi Denis-Courmont
Date Sept. 22, 2008, 3:47 p.m.
Message ID <1222098445-26175-5-git-send-email-remi.denis-courmont@nokia.com>
Download mbox | patch
Permalink /patch/885/
State Accepted
Delegated to: David Miller
Headers show

Comments

Rémi Denis-Courmont - Sept. 22, 2008, 3:47 p.m.
This provides support for configuring Phonet addresses, notifying
Phonet configuration changes, and dumping the configuration.

Signed-off-by: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
---
 include/net/phonet/phonet.h |    1 +
 net/phonet/Makefile         |    1 +
 net/phonet/af_phonet.c      |    1 +
 net/phonet/pn_netlink.c     |  186 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 189 insertions(+), 0 deletions(-)
 create mode 100644 net/phonet/pn_netlink.c
Thomas Graf - Sept. 23, 2008, 12:10 p.m.
Hello!

* R?mi Denis-Courmont <remi.denis-courmont@nokia.com> 2008-09-22 18:47
> +static int newaddr_doit(struct sk_buff *skb, struct nlmsghdr *nlm, void *attr)
> +{
> +	struct rtattr **rta = attr;
> +	struct ifaddrmsg *ifm = NLMSG_DATA(nlm);
> +	struct net_device *dev;
> +	int err;
> +	u8 pnaddr;
> +
> +	if (!capable(CAP_SYS_ADMIN))
> +		return -EPERM;
> +
> +	ASSERT_RTNL();
> +
> +	if (rta[IFA_LOCAL - 1] == NULL)
> +		return -EINVAL;

Please do not use the old attribute buffer anymore. It's use is racy
ever since we started dropping the rtnl semaphore in order to load
modules. It would be safe in this particular case but it shouldn't be
used for new code.

Take a look at rtnl_setlink() for an example on how to use the interface
correctly.

> +	memcpy(&pnaddr, RTA_DATA(rta[IFA_LOCAL - 1]), 1);

This is not safe, the attribute payload needs to be verified before its
use.

Please use the new netlink interface, all functions named RTA_ or rattr_
are deprecated. The new interface provides a trivial method to validate
attributes while they are being parsed.

> +static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
> +			u32 pid, u32 seq, int event)
> +{
> +	struct ifaddrmsg *ifm;
> +	struct nlmsghdr *nlh;
> +	unsigned int orig_len = skb->len;
> +
> +	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(struct ifaddrmsg));
> +	ifm = NLMSG_DATA(nlh);

Please use nlmsg_put() and nlmsg_data()

> +	ifm->ifa_family = AF_PHONET;
> +	ifm->ifa_prefixlen = 0;
> +	ifm->ifa_flags = IFA_F_PERMANENT;
> +	ifm->ifa_scope = RT_SCOPE_HOST;
> +	ifm->ifa_index = dev->ifindex;
> +	RTA_PUT(skb, IFA_LOCAL, 1, &addr);
> +	nlh->nlmsg_len = skb->len - orig_len;

See rtnl_fill_ifinfo() for an example.
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Patch

diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
index c53f2ab..8b77794 100644
--- a/include/net/phonet/phonet.h
+++ b/include/net/phonet/phonet.h
@@ -71,4 +71,5 @@  struct phonet_protocol {
 int phonet_proto_register(int protocol, struct phonet_protocol *pp);
 void phonet_proto_unregister(int protocol, struct phonet_protocol *pp);
 
+void phonet_netlink_register(void);
 #endif
diff --git a/net/phonet/Makefile b/net/phonet/Makefile
index 980a386..4143c3e 100644
--- a/net/phonet/Makefile
+++ b/net/phonet/Makefile
@@ -2,4 +2,5 @@  obj-$(CONFIG_PHONET) += phonet.o
 
 phonet-objs := \
 	pn_dev.o \
+	pn_netlink.o \
 	af_phonet.o
diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index a8ba6f1..5c729ba 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -203,6 +203,7 @@  static int __init phonet_init(void)
 
 	phonet_device_init();
 	dev_add_pack(&phonet_packet_type);
+	phonet_netlink_register();
 	return 0;
 }
 
diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c
new file mode 100644
index 0000000..b1ea19a
--- /dev/null
+++ b/net/phonet/pn_netlink.c
@@ -0,0 +1,186 @@ 
+/*
+ * File: pn_netlink.c
+ *
+ * Phonet netlink interface
+ *
+ * Copyright (C) 2008 Nokia Corporation.
+ *
+ * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
+ * Original author: Sakari Ailus <sakari.ailus@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/netlink.h>
+#include <linux/phonet.h>
+#include <net/sock.h>
+#include <net/phonet/pn_dev.h>
+
+static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
+		     u32 pid, u32 seq, int event);
+
+static void rtmsg_notify(int event, struct net_device *dev, u8 addr)
+{
+	struct sk_buff *skb;
+	int err = -ENOBUFS;
+
+	skb = nlmsg_new(NLMSG_ALIGN(sizeof(struct ifaddrmsg)) +
+			nla_total_size(1), GFP_KERNEL);
+	if (skb == NULL)
+		goto errout;
+	err = fill_addr(skb, dev, addr, 0, 0, event);
+	if (err < 0) {
+		WARN_ON(err == -EMSGSIZE);
+		kfree_skb(skb);
+		goto errout;
+	}
+	err = rtnl_notify(skb, dev_net(dev), 0,
+			  RTNLGRP_PHONET_IFADDR, NULL, GFP_KERNEL);
+errout:
+	if (err < 0)
+		rtnl_set_sk_err(dev_net(dev), RTNLGRP_PHONET_IFADDR, err);
+}
+
+static int newaddr_doit(struct sk_buff *skb, struct nlmsghdr *nlm, void *attr)
+{
+	struct rtattr **rta = attr;
+	struct ifaddrmsg *ifm = NLMSG_DATA(nlm);
+	struct net_device *dev;
+	int err;
+	u8 pnaddr;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	ASSERT_RTNL();
+
+	if (rta[IFA_LOCAL - 1] == NULL)
+		return -EINVAL;
+
+	dev = __dev_get_by_index(&init_net, ifm->ifa_index);
+	if (dev == NULL)
+		return -ENODEV;
+
+	if (ifm->ifa_prefixlen > 0)
+		return -EINVAL;
+
+	memcpy(&pnaddr, RTA_DATA(rta[IFA_LOCAL - 1]), 1);
+
+	err = phonet_address_add(dev, pnaddr);
+	if (!err)
+		rtmsg_notify(RTM_NEWADDR, dev, pnaddr);
+	return err;
+}
+
+static int deladdr_doit(struct sk_buff *skb, struct nlmsghdr *nlm, void *attr)
+{
+	struct rtattr **rta = attr;
+	struct ifaddrmsg *ifm = NLMSG_DATA(nlm);
+	struct net_device *dev;
+	int err;
+	u8 pnaddr;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	ASSERT_RTNL();
+
+	if (rta[IFA_LOCAL - 1] == NULL)
+		return -EINVAL;
+
+	dev = __dev_get_by_index(&init_net, ifm->ifa_index);
+	if (dev == NULL)
+		return -ENODEV;
+
+	if (ifm->ifa_prefixlen > 0)
+		return -EADDRNOTAVAIL;
+
+	memcpy(&pnaddr, RTA_DATA(rta[IFA_LOCAL - 1]), 1);
+
+	err = phonet_address_del(dev, pnaddr);
+	if (!err)
+		rtmsg_notify(RTM_DELADDR, dev, pnaddr);
+	return err;
+}
+
+static int fill_addr(struct sk_buff *skb, struct net_device *dev, u8 addr,
+			u32 pid, u32 seq, int event)
+{
+	struct ifaddrmsg *ifm;
+	struct nlmsghdr *nlh;
+	unsigned int orig_len = skb->len;
+
+	nlh = NLMSG_PUT(skb, pid, seq, event, sizeof(struct ifaddrmsg));
+	ifm = NLMSG_DATA(nlh);
+	ifm->ifa_family = AF_PHONET;
+	ifm->ifa_prefixlen = 0;
+	ifm->ifa_flags = IFA_F_PERMANENT;
+	ifm->ifa_scope = RT_SCOPE_HOST;
+	ifm->ifa_index = dev->ifindex;
+	RTA_PUT(skb, IFA_LOCAL, 1, &addr);
+	nlh->nlmsg_len = skb->len - orig_len;
+
+	return 0;
+
+nlmsg_failure:
+rtattr_failure:
+	skb_trim(skb, orig_len);
+
+	return -1;
+}
+
+static int getaddr_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct phonet_device *pnd;
+	int dev_idx = 0, dev_start_idx = cb->args[0];
+	int addr_idx = 0, addr_start_idx = cb->args[1];
+
+	spin_lock_bh(&pndevs.lock);
+	list_for_each_entry(pnd, &pndevs.list, list) {
+		u8 addr;
+
+		if (dev_idx > dev_start_idx)
+			addr_start_idx = 0;
+		if (dev_idx++ < dev_start_idx)
+			continue;
+
+		addr_idx = 0;
+		for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
+			addr = find_next_bit(pnd->addrs, 64, 1+addr)) {
+			if (addr_idx++ < addr_start_idx)
+				continue;
+
+			if (fill_addr(skb, pnd->netdev, addr << 2,
+					 NETLINK_CB(cb->skb).pid,
+					cb->nlh->nlmsg_seq, RTM_NEWADDR))
+				goto out;
+		}
+	}
+
+out:
+	spin_unlock_bh(&pndevs.lock);
+	cb->args[0] = dev_idx;
+	cb->args[1] = addr_idx;
+
+	return skb->len;
+}
+
+void __init phonet_netlink_register(void)
+{
+	rtnl_register(PF_PHONET, RTM_NEWADDR, newaddr_doit, NULL);
+	rtnl_register(PF_PHONET, RTM_DELADDR, deladdr_doit, NULL);
+	rtnl_register(PF_PHONET, RTM_GETADDR, NULL, getaddr_dumpit);
+}