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Date: Wed, 27 Apr 2011 10:57:05 +0200
From: Kurt Van Dijck <kurt.van.dijck@....be>
To: socketcan-core@...ts.berlios.de, netdev@...r.kernel.org
Subject: [PATCH v4 2/5] can: add rtnetlink support
This patch adds rtnetlink support for AF_CAN. This support is really
a multiplexer towards the different CAN protocols.
Signed-off-by: Kurt Van Dijck <kurt.van.dijck@....be>
---
include/linux/can/core.h | 26 +++++-
net/can/af_can.c | 240 +++++++++++++++++++++++++++++++++++++++++++---
net/can/bcm.c | 2 +-
net/can/raw.c | 2 +-
4 files changed, 253 insertions(+), 17 deletions(-)
diff --git a/include/linux/can/core.h b/include/linux/can/core.h
index d803a5e..7ffd839 100644
--- a/include/linux/can/core.h
+++ b/include/linux/can/core.h
@@ -18,6 +18,7 @@
#include <linux/can.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
+#include <net/rtnetlink.h>
#define CAN_VERSION "20090105"
@@ -40,6 +41,27 @@ struct can_proto {
int protocol;
const struct proto_ops *ops;
struct proto *prot;
+ const struct rtnl_af_ops *rtnl_link_ops;
+ /*
+ * hooks for rtnl hooks
+ * for the *dump* functions, cb->args[0] is reserved
+ * for use by af_can.c, so keep your fingers off.
+ */
+ rtnl_doit_func rtnl_new_addr;
+ rtnl_doit_func rtnl_del_addr;
+ rtnl_dumpit_func rtnl_dump_addr;
+};
+
+/*
+ * this is quite a dirty hack:
+ * reuse the second byte of a rtnetlink msg
+ * to indicate the precise protocol.
+ * The major problem is that is may conflict
+ * with the prefixlen in struct ifaddrmsg.
+ */
+struct rtgencanmsg {
+ unsigned char rtgen_family;
+ unsigned char can_protocol;
};
/*
@@ -53,8 +75,8 @@ struct can_proto {
/* function prototypes for the CAN networklayer core (af_can.c) */
-extern int can_proto_register(struct can_proto *cp);
-extern void can_proto_unregister(struct can_proto *cp);
+extern int can_proto_register(const struct can_proto *cp);
+extern void can_proto_unregister(const struct can_proto *cp);
extern int can_rx_register(struct net_device *dev, canid_t can_id,
canid_t mask,
diff --git a/net/can/af_can.c b/net/can/af_can.c
index a8dcaa4..c7e9cdf 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -3,6 +3,7 @@
* (used by different CAN protocol modules)
*
* Copyright (c) 2002-2007 Volkswagen Group Electronic Research
+ * Copyright (C) 2011 Kurt Van Dijck <kurt.van.dijck@....be>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -69,7 +70,8 @@ static __initdata const char banner[] = KERN_INFO
MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <urs.thuermann@...kswagen.de>, "
- "Oliver Hartkopp <oliver.hartkopp@...kswagen.de>");
+ "Oliver Hartkopp <oliver.hartkopp@...kswagen.de>, "
+ "Kurt Van Dijck <kurt.van.dijck@....be>");
MODULE_ALIAS_NETPROTO(PF_CAN);
@@ -84,7 +86,7 @@ static DEFINE_SPINLOCK(can_rcvlists_lock);
static struct kmem_cache *rcv_cache __read_mostly;
/* table of registered CAN protocols */
-static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
+static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
static DEFINE_MUTEX(proto_tab_lock);
struct timer_list can_stattimer; /* timer for statistics update */
@@ -115,9 +117,9 @@ static void can_sock_destruct(struct sock *sk)
skb_queue_purge(&sk->sk_receive_queue);
}
-static struct can_proto *can_try_module_get(int protocol)
+static const struct can_proto *can_try_module_get(int protocol)
{
- struct can_proto *cp;
+ const struct can_proto *cp;
rcu_read_lock();
cp = rcu_dereference(proto_tab[protocol]);
@@ -128,18 +130,20 @@ static struct can_proto *can_try_module_get(int protocol)
return cp;
}
+static inline void can_put_proto(const struct can_proto *cp)
+{
+ module_put(cp->prot->owner);
+}
+
static int can_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk;
- struct can_proto *cp;
+ const struct can_proto *cp;
int err = 0;
sock->state = SS_UNCONNECTED;
- if (protocol < 0 || protocol >= CAN_NPROTO)
- return -EINVAL;
-
if (!net_eq(net, &init_net))
return -EAFNOSUPPORT;
@@ -166,8 +170,8 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
/* check for available protocol and correct usage */
- if (!cp)
- return -EPROTONOSUPPORT;
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
if (cp->type != sock->type) {
err = -EPROTOTYPE;
@@ -195,7 +199,7 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
}
errout:
- module_put(cp->prot->owner);
+ can_put_proto(cp);
return err;
}
@@ -691,7 +695,7 @@ drop:
* -EBUSY protocol already in use
* -ENOBUF if proto_register() fails
*/
-int can_proto_register(struct can_proto *cp)
+int can_proto_register(const struct can_proto *cp)
{
int proto = cp->protocol;
int err = 0;
@@ -728,7 +732,7 @@ EXPORT_SYMBOL(can_proto_register);
* can_proto_unregister - unregister CAN transport protocol
* @cp: pointer to CAN protocol structure
*/
-void can_proto_unregister(struct can_proto *cp)
+void can_proto_unregister(const struct can_proto *cp)
{
int proto = cp->protocol;
@@ -818,6 +822,206 @@ static struct notifier_block can_netdev_notifier __read_mostly = {
.notifier_call = can_notifier,
};
+/*
+ * RTNETLINK
+ */
+static int can_rtnl_doit(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+{
+ int ret, protocol;
+ const struct can_proto *cp;
+ rtnl_doit_func fn;
+
+ protocol = ((struct rtgencanmsg *)NLMSG_DATA(nlh))->can_protocol;
+ /* since rtnl_lock is held, dont try to load protocol */
+ cp = can_get_proto(protocol, 0);
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
+
+ switch (nlh->nlmsg_type) {
+ case RTM_NEWADDR:
+ fn = cp->rtnl_new_addr;
+ break;
+ case RTM_DELADDR:
+ fn = cp->rtnl_del_addr;
+ break;
+ default:
+ fn = 0;
+ break;
+ }
+ if (fn)
+ ret = fn(skb, nlh, arg);
+ else
+ ret = -EPROTONOSUPPORT;
+ can_put_proto(cp);
+ return ret;
+}
+
+static int can_rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb,
+ int offset)
+{
+ int ret, j;
+ const struct can_proto *cp;
+ rtnl_dumpit_func fn;
+
+ ret = 0;
+ for (j = cb->args[0]; j < CAN_NPROTO; ++j) {
+ /* save state */
+ cb->args[0] = j;
+ cp = can_get_proto(j, 0);
+ if (IS_ERR(cp))
+ /* we are looping, any error is our own fault */
+ continue;
+ fn = *((rtnl_dumpit_func *)(&((const uint8_t *)cp)[offset]));
+ if (fn)
+ ret = fn(skb, cb);
+ can_put_proto(cp);
+ if (ret < 0)
+ /* suspend this skb */
+ return ret;
+ }
+ return ret;
+}
+
+static int can_rtnl_dump_addr(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ return can_rtnl_dumpit(skb, cb,
+ offsetof(struct can_proto, rtnl_dump_addr));
+}
+
+/*
+ * LINK AF properties
+ */
+static size_t can_get_link_af_size(const struct net_device *dev)
+{
+ int ret, j, total;
+ const struct can_proto *cp;
+
+ if (!net_eq(dev_net(dev), &init_net) || (dev->type != ARPHRD_CAN))
+ return 0;
+
+ total = 0;
+ for (j = 0; j < CAN_NPROTO; ++j) {
+ cp = can_try_mdoule_get(j);
+ if (IS_ERR(cp))
+ /* no worry */
+ continue;
+ ret = 0;
+ if (cp->rtnl_link_ops && cp->rtnl_link_ops->get_link_af_size)
+ ret = cp->rtnl_link_ops->get_link_af_size(dev) +
+ nla_total_size(sizeof(struct nlattr));
+ can_put_proto(cp);
+ if (ret < 0)
+ return ret;
+ total += ret;
+ }
+ return nla_total_size(total);
+}
+
+static int can_fill_link_af(struct sk_buff *skb, const struct net_device *dev)
+{
+ int ret, j, n;
+ struct nlattr *nla;
+ const struct can_proto *cp;
+
+ if (!net_eq(dev_net(dev), &init_net) || (dev->type != ARPHRD_CAN))
+ return -ENODATA;
+
+ n = 0;
+ for (j = 0; j < CAN_NPROTO; ++j) {
+ cp = can_try_module_get(j);
+ if (IS_ERR(cp))
+ /* no worry */
+ continue;
+ if (cp->rtnl_link_ops && cp->rtnl_link_ops->fill_link_af) {
+ nla = nla_nest_start(skb, j);
+ if (!nla)
+ goto nla_put_failure;
+
+ ret = cp->rtnl_link_ops->fill_link_af(skb, dev);
+ /*
+ * Caller may return ENODATA to indicate that there
+ * was no data to be dumped. This is not an error, it
+ * means we should trim the attribute header and
+ * continue.
+ */
+ if (ret == -ENODATA)
+ nla_nest_cancel(skb, nla);
+ else if (ret < 0)
+ goto nla_put_failure;
+ nla_nest_end(skb, nla);
+ ++n;
+ }
+ can_put_proto(cp);
+ }
+ return n ? 0 : -ENODATA;
+
+nla_put_failure:
+ nla_nest_cancel(skb, nla);
+ can_put_proto(cp);
+ return -EMSGSIZE;
+}
+
+static int can_validate_link_af(const struct net_device *dev,
+ const struct nlattr *nla)
+{
+ int ret, rem;
+ const struct can_proto *cp;
+ struct nlattr *prot;
+
+ if (!net_eq(dev_net(dev), &init_net) || (dev->type != ARPHRD_CAN))
+ return -EPROTONOSUPPORT;
+
+ nla_for_each_nested(prot, nla, rem) {
+ cp = can_try_module_get(nla_type(prot));
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
+ if (!cp->rtnl_link_ops)
+ ret = -EPROTONOSUPPORT;
+ else if (!cp->rtnl_link_ops->validate_link_af)
+ ret = 0;
+ else
+ ret = cp->rtnl_link_ops->validate_link_af(dev, prot);
+ can_put_proto(cp);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
+static int can_set_link_af(struct net_device *dev, const struct nlattr *nla)
+{
+ int ret, rem;
+ const struct can_proto *cp;
+ struct nlattr *prot;
+
+ if (!net_eq(dev_net(dev), &init_net) || (dev->type != ARPHRD_CAN))
+ return -EPROTONOSUPPORT;
+
+ nla_for_each_nested(prot, nla, rem) {
+ cp = can_try_module_get(nla_type(prot));
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
+ if (!cp->rtnl_link_ops || !cp->rtnl_link_ops->set_link_af)
+ ret = -EPROTONOSUPPORT;
+ else
+ ret = cp->rtnl_link_ops->set_link_af(dev, prot);
+ can_put_proto(cp);
+ if (ret < 0)
+ return ret;
+ }
+ return 0;
+}
+
+static struct rtnl_af_ops can_rtnl_af_ops = {
+ .family = AF_CAN,
+ .fill_link_af = can_fill_link_af,
+ .get_link_af_size = can_get_link_af_size,
+ .validate_link_af = can_validate_link_af,
+ .set_link_af = can_set_link_af,
+};
+
+/* exported init */
+
static __init int can_init(void)
{
printk(banner);
@@ -843,6 +1047,11 @@ static __init int can_init(void)
register_netdevice_notifier(&can_netdev_notifier);
dev_add_pack(&can_packet);
+ rtnl_af_register(&can_rtnl_af_ops);
+ rtnl_register(PF_CAN, RTM_NEWADDR, can_rtnl_doit, NULL);
+ rtnl_register(PF_CAN, RTM_DELADDR, can_rtnl_doit, NULL);
+ rtnl_register(PF_CAN, RTM_GETADDR, NULL, can_rtnl_dump_addr);
+
return 0;
}
@@ -853,6 +1062,11 @@ static __exit void can_exit(void)
if (stats_timer)
del_timer(&can_stattimer);
+ rtnl_unregister(PF_CAN, RTM_NEWADDR);
+ rtnl_unregister(PF_CAN, RTM_DELADDR);
+ rtnl_unregister(PF_CAN, RTM_GETADDR);
+ rtnl_af_unregister(&can_rtnl_af_ops);
+
can_remove_proc();
/* protocol unregister */
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 3dc4d4e..4f65f4f 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1601,7 +1601,7 @@ static struct proto bcm_proto __read_mostly = {
.init = bcm_init,
};
-static struct can_proto bcm_can_proto __read_mostly = {
+static const struct can_proto bcm_can_proto = {
.type = SOCK_DGRAM,
.protocol = CAN_BCM,
.ops = &bcm_ops,
diff --git a/net/can/raw.c b/net/can/raw.c
index 6009d5e..60d4282 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -774,7 +774,7 @@ static struct proto raw_proto __read_mostly = {
.init = raw_init,
};
-static struct can_proto raw_can_proto __read_mostly = {
+static const struct can_proto raw_can_proto = {
.type = SOCK_RAW,
.protocol = CAN_RAW,
.ops = &raw_ops,
--
1.7.2.5
--
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