linux/net/decnet/dn_rules.c
Steven Whitehouse ecba320f2e [DECnet]: Use RCU locking in dn_rules.c
As per Robert Olsson's patch for ipv4, this is the DECnet
version to keep the code "in step". It changes the list
of rules to use RCU rather than an rwlock.

Inspired-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: Steven Whitehouse <steve@chygwyn.com>
Signed-off-by: Patrick Caulfield <patrick@tykepenguin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:43:28 -08:00

426 lines
10 KiB
C

/*
* DECnet An implementation of the DECnet protocol suite for the LINUX
* operating system. DECnet is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* DECnet Routing Forwarding Information Base (Rules)
*
* Author: Steve Whitehouse <SteveW@ACM.org>
* Mostly copied from Alexey Kuznetsov's ipv4/fib_rules.c
*
*
* Changes:
*
*/
#include <linux/config.h>
#include <linux/string.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/proc_fs.h>
#include <linux/netdevice.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/in_route.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <asm/atomic.h>
#include <asm/uaccess.h>
#include <net/neighbour.h>
#include <net/dst.h>
#include <net/flow.h>
#include <net/dn.h>
#include <net/dn_fib.h>
#include <net/dn_neigh.h>
#include <net/dn_dev.h>
struct dn_fib_rule
{
struct hlist_node r_hlist;
atomic_t r_clntref;
u32 r_preference;
unsigned char r_table;
unsigned char r_action;
unsigned char r_dst_len;
unsigned char r_src_len;
__le16 r_src;
__le16 r_srcmask;
__le16 r_dst;
__le16 r_dstmask;
__le16 r_srcmap;
u8 r_flags;
#ifdef CONFIG_DECNET_ROUTE_FWMARK
u32 r_fwmark;
#endif
int r_ifindex;
char r_ifname[IFNAMSIZ];
int r_dead;
struct rcu_head rcu;
};
static struct dn_fib_rule default_rule = {
.r_clntref = ATOMIC_INIT(2),
.r_preference = 0x7fff,
.r_table = RT_TABLE_MAIN,
.r_action = RTN_UNICAST
};
static struct hlist_head dn_fib_rules;
int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
struct rtattr **rta = arg;
struct rtmsg *rtm = NLMSG_DATA(nlh);
struct dn_fib_rule *r;
struct hlist_node *node;
int err = -ESRCH;
hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
rtm->rtm_src_len == r->r_src_len &&
rtm->rtm_dst_len == r->r_dst_len &&
(!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 2) == 0) &&
#ifdef CONFIG_DECNET_ROUTE_FWMARK
(!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
#endif
(!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
(!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
(!rta[RTA_IIF-1] || rtattr_strcmp(rta[RTA_IIF-1], r->r_ifname) == 0) &&
(!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
err = -EPERM;
if (r == &default_rule)
break;
hlist_del_rcu(&r->r_hlist);
r->r_dead = 1;
dn_fib_rule_put(r);
err = 0;
break;
}
}
return err;
}
static inline void dn_fib_rule_put_rcu(struct rcu_head *head)
{
struct dn_fib_rule *r = container_of(head, struct dn_fib_rule, rcu);
kfree(r);
}
void dn_fib_rule_put(struct dn_fib_rule *r)
{
if (atomic_dec_and_test(&r->r_clntref)) {
if (r->r_dead)
call_rcu(&r->rcu, dn_fib_rule_put_rcu);
else
printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
}
}
int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
struct rtattr **rta = arg;
struct rtmsg *rtm = NLMSG_DATA(nlh);
struct dn_fib_rule *r, *new_r, *last = NULL;
struct hlist_node *node = NULL;
unsigned char table_id;
if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
return -EINVAL;
if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
return -EINVAL;
if (rtm->rtm_type == RTN_NAT)
return -EINVAL;
table_id = rtm->rtm_table;
if (table_id == RT_TABLE_UNSPEC) {
struct dn_fib_table *tb;
if (rtm->rtm_type == RTN_UNICAST) {
if ((tb = dn_fib_empty_table()) == NULL)
return -ENOBUFS;
table_id = tb->n;
}
}
new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
if (!new_r)
return -ENOMEM;
memset(new_r, 0, sizeof(*new_r));
if (rta[RTA_SRC-1])
memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
if (rta[RTA_DST-1])
memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 2);
if (rta[RTA_GATEWAY-1])
memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 2);
new_r->r_src_len = rtm->rtm_src_len;
new_r->r_dst_len = rtm->rtm_dst_len;
new_r->r_srcmask = dnet_make_mask(rtm->rtm_src_len);
new_r->r_dstmask = dnet_make_mask(rtm->rtm_dst_len);
#ifdef CONFIG_DECNET_ROUTE_FWMARK
if (rta[RTA_PROTOINFO-1])
memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
#endif
new_r->r_action = rtm->rtm_type;
new_r->r_flags = rtm->rtm_flags;
if (rta[RTA_PRIORITY-1])
memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
new_r->r_table = table_id;
if (rta[RTA_IIF-1]) {
struct net_device *dev;
rtattr_strlcpy(new_r->r_ifname, rta[RTA_IIF-1], IFNAMSIZ);
new_r->r_ifindex = -1;
dev = dev_get_by_name(new_r->r_ifname);
if (dev) {
new_r->r_ifindex = dev->ifindex;
dev_put(dev);
}
}
r = container_of(dn_fib_rules.first, struct dn_fib_rule, r_hlist);
if (!new_r->r_preference) {
if (r && r->r_hlist.next != NULL) {
r = container_of(r->r_hlist.next, struct dn_fib_rule, r_hlist);
if (r->r_preference)
new_r->r_preference = r->r_preference - 1;
}
}
hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
if (r->r_preference > new_r->r_preference)
break;
last = r;
}
atomic_inc(&new_r->r_clntref);
if (last)
hlist_add_after_rcu(&last->r_hlist, &new_r->r_hlist);
else
hlist_add_before_rcu(&new_r->r_hlist, &r->r_hlist);
return 0;
}
int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
{
struct dn_fib_rule *r, *policy;
struct dn_fib_table *tb;
__le16 saddr = flp->fld_src;
__le16 daddr = flp->fld_dst;
struct hlist_node *node;
int err;
rcu_read_lock();
hlist_for_each_entry_rcu(r, node, &dn_fib_rules, r_hlist) {
if (((saddr^r->r_src) & r->r_srcmask) ||
((daddr^r->r_dst) & r->r_dstmask) ||
#ifdef CONFIG_DECNET_ROUTE_FWMARK
(r->r_fwmark && r->r_fwmark != flp->fld_fwmark) ||
#endif
(r->r_ifindex && r->r_ifindex != flp->iif))
continue;
switch(r->r_action) {
case RTN_UNICAST:
case RTN_NAT:
policy = r;
break;
case RTN_UNREACHABLE:
rcu_read_unlock();
return -ENETUNREACH;
default:
case RTN_BLACKHOLE:
rcu_read_unlock();
return -EINVAL;
case RTN_PROHIBIT:
rcu_read_unlock();
return -EACCES;
}
if ((tb = dn_fib_get_table(r->r_table, 0)) == NULL)
continue;
err = tb->lookup(tb, flp, res);
if (err == 0) {
res->r = policy;
if (policy)
atomic_inc(&policy->r_clntref);
rcu_read_unlock();
return 0;
}
if (err < 0 && err != -EAGAIN) {
rcu_read_unlock();
return err;
}
}
rcu_read_unlock();
return -ESRCH;
}
unsigned dnet_addr_type(__le16 addr)
{
struct flowi fl = { .nl_u = { .dn_u = { .daddr = addr } } };
struct dn_fib_res res;
unsigned ret = RTN_UNICAST;
struct dn_fib_table *tb = dn_fib_tables[RT_TABLE_LOCAL];
res.r = NULL;
if (tb) {
if (!tb->lookup(tb, &fl, &res)) {
ret = res.type;
dn_fib_res_put(&res);
}
}
return ret;
}
__le16 dn_fib_rules_policy(__le16 saddr, struct dn_fib_res *res, unsigned *flags)
{
struct dn_fib_rule *r = res->r;
if (r->r_action == RTN_NAT) {
int addrtype = dnet_addr_type(r->r_srcmap);
if (addrtype == RTN_NAT) {
saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
*flags |= RTCF_SNAT;
} else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
saddr = r->r_srcmap;
*flags |= RTCF_MASQ;
}
}
return saddr;
}
static void dn_fib_rules_detach(struct net_device *dev)
{
struct hlist_node *node;
struct dn_fib_rule *r;
hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
if (r->r_ifindex == dev->ifindex)
r->r_ifindex = -1;
}
}
static void dn_fib_rules_attach(struct net_device *dev)
{
struct hlist_node *node;
struct dn_fib_rule *r;
hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
r->r_ifindex = dev->ifindex;
}
}
static int dn_fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
switch(event) {
case NETDEV_UNREGISTER:
dn_fib_rules_detach(dev);
dn_fib_sync_down(0, dev, 1);
case NETDEV_REGISTER:
dn_fib_rules_attach(dev);
dn_fib_sync_up(dev);
}
return NOTIFY_DONE;
}
static struct notifier_block dn_fib_rules_notifier = {
.notifier_call = dn_fib_rules_event,
};
static int dn_fib_fill_rule(struct sk_buff *skb, struct dn_fib_rule *r,
struct netlink_callback *cb, unsigned int flags)
{
struct rtmsg *rtm;
struct nlmsghdr *nlh;
unsigned char *b = skb->tail;
nlh = NLMSG_NEW_ANSWER(skb, cb, RTM_NEWRULE, sizeof(*rtm), flags);
rtm = NLMSG_DATA(nlh);
rtm->rtm_family = AF_DECnet;
rtm->rtm_dst_len = r->r_dst_len;
rtm->rtm_src_len = r->r_src_len;
rtm->rtm_tos = 0;
#ifdef CONFIG_DECNET_ROUTE_FWMARK
if (r->r_fwmark)
RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
#endif
rtm->rtm_table = r->r_table;
rtm->rtm_protocol = 0;
rtm->rtm_scope = 0;
rtm->rtm_type = r->r_action;
rtm->rtm_flags = r->r_flags;
if (r->r_dst_len)
RTA_PUT(skb, RTA_DST, 2, &r->r_dst);
if (r->r_src_len)
RTA_PUT(skb, RTA_SRC, 2, &r->r_src);
if (r->r_ifname[0])
RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
if (r->r_preference)
RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
if (r->r_srcmap)
RTA_PUT(skb, RTA_GATEWAY, 2, &r->r_srcmap);
nlh->nlmsg_len = skb->tail - b;
return skb->len;
nlmsg_failure:
rtattr_failure:
skb_trim(skb, b - skb->data);
return -1;
}
int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
{
int idx = 0;
int s_idx = cb->args[0];
struct dn_fib_rule *r;
struct hlist_node *node;
rcu_read_lock();
hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
if (idx < s_idx)
continue;
if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
break;
idx++;
}
rcu_read_unlock();
cb->args[0] = idx;
return skb->len;
}
void __init dn_fib_rules_init(void)
{
INIT_HLIST_HEAD(&dn_fib_rules);
hlist_add_head(&default_rule.r_hlist, &dn_fib_rules);
register_netdevice_notifier(&dn_fib_rules_notifier);
}
void __exit dn_fib_rules_cleanup(void)
{
unregister_netdevice_notifier(&dn_fib_rules_notifier);
}