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Diffstat (limited to 'net/can/gw.c')
-rw-r--r--net/can/gw.c160
1 files changed, 109 insertions, 51 deletions
diff --git a/net/can/gw.c b/net/can/gw.c
index 574dda78eb0..050a2110d43 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -42,6 +42,7 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
+#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
@@ -52,19 +53,31 @@
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
+#include <linux/can/skb.h>
#include <linux/can/gw.h>
#include <net/rtnetlink.h>
#include <net/net_namespace.h>
#include <net/sock.h>
-#define CAN_GW_VERSION "20101209"
-static __initconst const char banner[] =
- KERN_INFO "can: netlink gateway (rev " CAN_GW_VERSION ")\n";
+#define CAN_GW_VERSION "20130117"
+#define CAN_GW_NAME "can-gw"
MODULE_DESCRIPTION("PF_CAN netlink gateway");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
-MODULE_ALIAS("can-gw");
+MODULE_ALIAS(CAN_GW_NAME);
+
+#define CGW_MIN_HOPS 1
+#define CGW_MAX_HOPS 6
+#define CGW_DEFAULT_HOPS 1
+
+static unsigned int max_hops __read_mostly = CGW_DEFAULT_HOPS;
+module_param(max_hops, uint, S_IRUGO);
+MODULE_PARM_DESC(max_hops,
+ "maximum " CAN_GW_NAME " routing hops for CAN frames "
+ "(valid values: " __stringify(CGW_MIN_HOPS) "-"
+ __stringify(CGW_MAX_HOPS) " hops, "
+ "default: " __stringify(CGW_DEFAULT_HOPS) ")");
static HLIST_HEAD(cgw_list);
static struct notifier_block notifier;
@@ -118,6 +131,7 @@ struct cgw_job {
struct rcu_head rcu;
u32 handled_frames;
u32 dropped_frames;
+ u32 deleted_frames;
struct cf_mod mod;
union {
/* CAN frame data source */
@@ -132,6 +146,7 @@ struct cgw_job {
/* tbc */
};
u8 gwtype;
+ u8 limit_hops;
u16 flags;
};
@@ -338,15 +353,38 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
struct sk_buff *nskb;
int modidx = 0;
- /* do not handle already routed frames - see comment below */
- if (skb_mac_header_was_set(skb))
+ /*
+ * Do not handle CAN frames routed more than 'max_hops' times.
+ * In general we should never catch this delimiter which is intended
+ * to cover a misconfiguration protection (e.g. circular CAN routes).
+ *
+ * The Controller Area Network controllers only accept CAN frames with
+ * correct CRCs - which are not visible in the controller registers.
+ * According to skbuff.h documentation the csum_start element for IP
+ * checksums is undefined/unsued when ip_summed == CHECKSUM_UNNECESSARY.
+ * Only CAN skbs can be processed here which already have this property.
+ */
+
+#define cgw_hops(skb) ((skb)->csum_start)
+
+ BUG_ON(skb->ip_summed != CHECKSUM_UNNECESSARY);
+
+ if (cgw_hops(skb) >= max_hops) {
+ /* indicate deleted frames due to misconfiguration */
+ gwj->deleted_frames++;
return;
+ }
if (!(gwj->dst.dev->flags & IFF_UP)) {
gwj->dropped_frames++;
return;
}
+ /* is sending the skb back to the incoming interface not allowed? */
+ if (!(gwj->flags & CGW_FLAGS_CAN_IIF_TX_OK) &&
+ can_skb_prv(skb)->ifindex == gwj->dst.dev->ifindex)
+ return;
+
/*
* clone the given skb, which has not been done in can_rcv()
*
@@ -363,15 +401,13 @@ static void can_can_gw_rcv(struct sk_buff *skb, void *data)
return;
}
- /*
- * Mark routed frames by setting some mac header length which is
- * not relevant for the CAN frames located in the skb->data section.
- *
- * As dev->header_ops is not set in CAN netdevices no one is ever
- * accessing the various header offsets in the CAN skbuffs anyway.
- * E.g. using the packet socket to read CAN frames is still working.
- */
- skb_set_mac_header(nskb, 8);
+ /* put the incremented hop counter in the cloned skb */
+ cgw_hops(nskb) = cgw_hops(skb) + 1;
+
+ /* first processing of this CAN frame -> adjust to private hop limit */
+ if (gwj->limit_hops && cgw_hops(nskb) == 1)
+ cgw_hops(nskb) = max_hops - gwj->limit_hops + 1;
+
nskb->dev = gwj->dst.dev;
/* pointer to modifiable CAN frame */
@@ -415,9 +451,9 @@ static inline void cgw_unregister_filter(struct cgw_job *gwj)
}
static int cgw_notifier(struct notifier_block *nb,
- unsigned long msg, void *data)
+ unsigned long msg, void *ptr)
{
- struct net_device *dev = (struct net_device *)data;
+ struct net_device *dev = netdev_notifier_info_to_dev(ptr);
if (!net_eq(dev_net(dev), &init_net))
return NOTIFY_DONE;
@@ -427,16 +463,16 @@ static int cgw_notifier(struct notifier_block *nb,
if (msg == NETDEV_UNREGISTER) {
struct cgw_job *gwj = NULL;
- struct hlist_node *n, *nx;
+ struct hlist_node *nx;
ASSERT_RTNL();
- hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+ hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
if (gwj->src.dev == dev || gwj->dst.dev == dev) {
hlist_del(&gwj->list);
cgw_unregister_filter(gwj);
- kfree(gwj);
+ kmem_cache_free(cgw_cache, gwj);
}
}
}
@@ -472,8 +508,18 @@ static int cgw_put_job(struct sk_buff *skb, struct cgw_job *gwj, int type,
goto cancel;
}
+ if (gwj->deleted_frames) {
+ if (nla_put_u32(skb, CGW_DELETED, gwj->deleted_frames) < 0)
+ goto cancel;
+ }
+
/* check non default settings of attributes */
+ if (gwj->limit_hops) {
+ if (nla_put_u8(skb, CGW_LIM_HOPS, gwj->limit_hops) < 0)
+ goto cancel;
+ }
+
if (gwj->mod.modtype.and) {
memcpy(&mb.cf, &gwj->mod.modframe.and, sizeof(mb.cf));
mb.modtype = gwj->mod.modtype.and;
@@ -540,12 +586,11 @@ cancel:
static int cgw_dump_jobs(struct sk_buff *skb, struct netlink_callback *cb)
{
struct cgw_job *gwj = NULL;
- struct hlist_node *n;
int idx = 0;
int s_idx = cb->args[0];
rcu_read_lock();
- hlist_for_each_entry_rcu(gwj, n, &cgw_list, list) {
+ hlist_for_each_entry_rcu(gwj, &cgw_list, list) {
if (idx < s_idx)
goto cont;
@@ -572,11 +617,12 @@ static const struct nla_policy cgw_policy[CGW_MAX+1] = {
[CGW_SRC_IF] = { .type = NLA_U32 },
[CGW_DST_IF] = { .type = NLA_U32 },
[CGW_FILTER] = { .len = sizeof(struct can_filter) },
+ [CGW_LIM_HOPS] = { .type = NLA_U8 },
};
/* check for common and gwtype specific attributes */
static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
- u8 gwtype, void *gwtypeattr)
+ u8 gwtype, void *gwtypeattr, u8 *limhops)
{
struct nlattr *tb[CGW_MAX+1];
struct cgw_frame_mod mb;
@@ -591,6 +637,13 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
if (err < 0)
return err;
+ if (tb[CGW_LIM_HOPS]) {
+ *limhops = nla_get_u8(tb[CGW_LIM_HOPS]);
+
+ if (*limhops < 1 || *limhops > max_hops)
+ return -EINVAL;
+ }
+
/* check for AND/OR/XOR/SET modifications */
if (tb[CGW_MOD_AND]) {
@@ -744,14 +797,14 @@ static int cgw_parse_attr(struct nlmsghdr *nlh, struct cf_mod *mod,
return 0;
}
-static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
- void *arg)
+static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct rtcanmsg *r;
struct cgw_job *gwj;
+ u8 limhops = 0;
int err = 0;
- if (!capable(CAP_NET_ADMIN))
+ if (!netlink_capable(skb, CAP_NET_ADMIN))
return -EPERM;
if (nlmsg_len(nlh) < sizeof(*r))
@@ -771,10 +824,12 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
gwj->handled_frames = 0;
gwj->dropped_frames = 0;
+ gwj->deleted_frames = 0;
gwj->flags = r->flags;
gwj->gwtype = r->gwtype;
- err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw);
+ err = cgw_parse_attr(nlh, &gwj->mod, CGW_TYPE_CAN_CAN, &gwj->ccgw,
+ &limhops);
if (err < 0)
goto out;
@@ -784,34 +839,29 @@ static int cgw_create_job(struct sk_buff *skb, struct nlmsghdr *nlh,
if (!gwj->ccgw.src_idx || !gwj->ccgw.dst_idx)
goto out;
- gwj->src.dev = dev_get_by_index(&init_net, gwj->ccgw.src_idx);
+ gwj->src.dev = __dev_get_by_index(&init_net, gwj->ccgw.src_idx);
if (!gwj->src.dev)
goto out;
- /* check for CAN netdev not using header_ops - see gw_rcv() */
- if (gwj->src.dev->type != ARPHRD_CAN || gwj->src.dev->header_ops)
- goto put_src_out;
+ if (gwj->src.dev->type != ARPHRD_CAN)
+ goto out;
- gwj->dst.dev = dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
+ gwj->dst.dev = __dev_get_by_index(&init_net, gwj->ccgw.dst_idx);
if (!gwj->dst.dev)
- goto put_src_out;
+ goto out;
- /* check for CAN netdev not using header_ops - see gw_rcv() */
- if (gwj->dst.dev->type != ARPHRD_CAN || gwj->dst.dev->header_ops)
- goto put_src_dst_out;
+ if (gwj->dst.dev->type != ARPHRD_CAN)
+ goto out;
+
+ gwj->limit_hops = limhops;
ASSERT_RTNL();
err = cgw_register_filter(gwj);
if (!err)
hlist_add_head_rcu(&gwj->list, &cgw_list);
-
-put_src_dst_out:
- dev_put(gwj->dst.dev);
-put_src_out:
- dev_put(gwj->src.dev);
out:
if (err)
kmem_cache_free(cgw_cache, gwj);
@@ -822,27 +872,28 @@ out:
static void cgw_remove_all_jobs(void)
{
struct cgw_job *gwj = NULL;
- struct hlist_node *n, *nx;
+ struct hlist_node *nx;
ASSERT_RTNL();
- hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+ hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
hlist_del(&gwj->list);
cgw_unregister_filter(gwj);
- kfree(gwj);
+ kmem_cache_free(cgw_cache, gwj);
}
}
-static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
+static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh)
{
struct cgw_job *gwj = NULL;
- struct hlist_node *n, *nx;
+ struct hlist_node *nx;
struct rtcanmsg *r;
struct cf_mod mod;
struct can_can_gw ccgw;
+ u8 limhops = 0;
int err = 0;
- if (!capable(CAP_NET_ADMIN))
+ if (!netlink_capable(skb, CAP_NET_ADMIN))
return -EPERM;
if (nlmsg_len(nlh) < sizeof(*r))
@@ -856,7 +907,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
if (r->gwtype != CGW_TYPE_CAN_CAN)
return -EINVAL;
- err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw);
+ err = cgw_parse_attr(nlh, &mod, CGW_TYPE_CAN_CAN, &ccgw, &limhops);
if (err < 0)
return err;
@@ -871,11 +922,14 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
ASSERT_RTNL();
/* remove only the first matching entry */
- hlist_for_each_entry_safe(gwj, n, nx, &cgw_list, list) {
+ hlist_for_each_entry_safe(gwj, nx, &cgw_list, list) {
if (gwj->flags != r->flags)
continue;
+ if (gwj->limit_hops != limhops)
+ continue;
+
if (memcmp(&gwj->mod, &mod, sizeof(mod)))
continue;
@@ -885,7 +939,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
hlist_del(&gwj->list);
cgw_unregister_filter(gwj);
- kfree(gwj);
+ kmem_cache_free(cgw_cache, gwj);
err = 0;
break;
}
@@ -895,7 +949,11 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
static __init int cgw_module_init(void)
{
- printk(banner);
+ /* sanitize given module parameter */
+ max_hops = clamp_t(unsigned int, max_hops, CGW_MIN_HOPS, CGW_MAX_HOPS);
+
+ pr_info("can: netlink gateway (rev " CAN_GW_VERSION ") max_hops=%d\n",
+ max_hops);
cgw_cache = kmem_cache_create("can_gw", sizeof(struct cgw_job),
0, 0, NULL);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-10 01:03:19 +0000