forked from Minki/linux
[IPV4]: Use RCU locking in fib_rules.
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Robert Olsson
David S. Miller
parent
d8dcffee86
commit
7b204afd45
@ -40,6 +40,8 @@
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/rcupdate.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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@ -52,7 +54,7 @@
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struct fib_rule
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{
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struct fib_rule *r_next;
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struct hlist_node hlist;
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atomic_t r_clntref;
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u32 r_preference;
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unsigned char r_table;
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@ -75,6 +77,7 @@ struct fib_rule
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#endif
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char r_ifname[IFNAMSIZ];
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int r_dead;
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struct rcu_head rcu;
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};
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static struct fib_rule default_rule = {
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@ -85,7 +88,6 @@ static struct fib_rule default_rule = {
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};
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static struct fib_rule main_rule = {
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.r_next = &default_rule,
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.r_clntref = ATOMIC_INIT(2),
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.r_preference = 0x7FFE,
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.r_table = RT_TABLE_MAIN,
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@ -93,23 +95,24 @@ static struct fib_rule main_rule = {
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};
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static struct fib_rule local_rule = {
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.r_next = &main_rule,
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.r_clntref = ATOMIC_INIT(2),
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.r_table = RT_TABLE_LOCAL,
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.r_action = RTN_UNICAST,
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};
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static struct fib_rule *fib_rules = &local_rule;
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static DEFINE_RWLOCK(fib_rules_lock);
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struct hlist_head fib_rules;
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/* writer func called from netlink -- rtnl_sem hold*/
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int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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{
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struct rtattr **rta = arg;
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struct rtmsg *rtm = NLMSG_DATA(nlh);
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struct fib_rule *r, **rp;
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struct fib_rule *r;
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struct hlist_node *node;
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int err = -ESRCH;
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for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {
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hlist_for_each_entry(r, node, &fib_rules, hlist) {
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if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&
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rtm->rtm_src_len == r->r_src_len &&
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rtm->rtm_dst_len == r->r_dst_len &&
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@ -126,10 +129,8 @@ int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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if (r == &local_rule)
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break;
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write_lock_bh(&fib_rules_lock);
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*rp = r->r_next;
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hlist_del_rcu(&r->hlist);
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r->r_dead = 1;
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write_unlock_bh(&fib_rules_lock);
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fib_rule_put(r);
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err = 0;
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break;
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@ -150,21 +151,30 @@ static struct fib_table *fib_empty_table(void)
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return NULL;
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}
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static inline void fib_rule_put_rcu(struct rcu_head *head)
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{
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struct fib_rule *r = container_of(head, struct fib_rule, rcu);
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kfree(r);
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}
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void fib_rule_put(struct fib_rule *r)
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{
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if (atomic_dec_and_test(&r->r_clntref)) {
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if (r->r_dead)
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kfree(r);
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call_rcu(&r->rcu, fib_rule_put_rcu);
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else
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printk("Freeing alive rule %p\n", r);
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}
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}
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/* writer func called from netlink -- rtnl_sem hold*/
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int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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{
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struct rtattr **rta = arg;
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struct rtmsg *rtm = NLMSG_DATA(nlh);
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struct fib_rule *r, *new_r, **rp;
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struct fib_rule *r, *new_r, *last = NULL;
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struct hlist_node *node = NULL;
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unsigned char table_id;
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if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
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@ -188,6 +198,7 @@ int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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if (!new_r)
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return -ENOMEM;
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memset(new_r, 0, sizeof(*new_r));
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if (rta[RTA_SRC-1])
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memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);
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if (rta[RTA_DST-1])
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@ -220,28 +231,28 @@ int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
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if (rta[RTA_FLOW-1])
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memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);
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#endif
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r = container_of(fib_rules.first, struct fib_rule, hlist);
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rp = &fib_rules;
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if (!new_r->r_preference) {
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r = fib_rules;
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if (r && (r = r->r_next) != NULL) {
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rp = &fib_rules->r_next;
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if (r && r->hlist.next != NULL) {
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r = container_of(r->hlist.next, struct fib_rule, hlist);
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if (r->r_preference)
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new_r->r_preference = r->r_preference - 1;
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}
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}
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while ( (r = *rp) != NULL ) {
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hlist_for_each_entry(r, node, &fib_rules, hlist) {
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if (r->r_preference > new_r->r_preference)
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break;
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rp = &r->r_next;
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last = r;
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}
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new_r->r_next = r;
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atomic_inc(&new_r->r_clntref);
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write_lock_bh(&fib_rules_lock);
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*rp = new_r;
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write_unlock_bh(&fib_rules_lock);
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if (last)
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hlist_add_after_rcu(&last->hlist, &new_r->hlist);
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else
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hlist_add_before_rcu(&new_r->hlist, &r->hlist);
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return 0;
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}
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@ -254,30 +265,30 @@ u32 fib_rules_tclass(struct fib_result *res)
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}
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#endif
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/* callers should hold rtnl semaphore */
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static void fib_rules_detach(struct net_device *dev)
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{
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struct hlist_node *node;
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struct fib_rule *r;
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for (r=fib_rules; r; r=r->r_next) {
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if (r->r_ifindex == dev->ifindex) {
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write_lock_bh(&fib_rules_lock);
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hlist_for_each_entry(r, node, &fib_rules, hlist) {
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if (r->r_ifindex == dev->ifindex)
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r->r_ifindex = -1;
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write_unlock_bh(&fib_rules_lock);
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}
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}
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}
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/* callers should hold rtnl semaphore */
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static void fib_rules_attach(struct net_device *dev)
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{
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struct hlist_node *node;
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struct fib_rule *r;
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for (r=fib_rules; r; r=r->r_next) {
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if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
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write_lock_bh(&fib_rules_lock);
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hlist_for_each_entry(r, node, &fib_rules, hlist) {
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if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
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r->r_ifindex = dev->ifindex;
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write_unlock_bh(&fib_rules_lock);
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}
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}
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}
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@ -286,14 +297,17 @@ int fib_lookup(const struct flowi *flp, struct fib_result *res)
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int err;
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struct fib_rule *r, *policy;
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struct fib_table *tb;
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struct hlist_node *node;
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u32 daddr = flp->fl4_dst;
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u32 saddr = flp->fl4_src;
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FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",
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NIPQUAD(flp->fl4_dst), NIPQUAD(flp->fl4_src));
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read_lock(&fib_rules_lock);
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for (r = fib_rules; r; r=r->r_next) {
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rcu_read_lock();
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hlist_for_each_entry_rcu(r, node, &fib_rules, hlist) {
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if (((saddr^r->r_src) & r->r_srcmask) ||
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((daddr^r->r_dst) & r->r_dstmask) ||
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(r->r_tos && r->r_tos != flp->fl4_tos) ||
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@ -309,14 +323,14 @@ FRprintk("tb %d r %d ", r->r_table, r->r_action);
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policy = r;
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break;
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case RTN_UNREACHABLE:
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return -ENETUNREACH;
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default:
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case RTN_BLACKHOLE:
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return -EINVAL;
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case RTN_PROHIBIT:
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return -EACCES;
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}
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@ -327,16 +341,16 @@ FRprintk("tb %d r %d ", r->r_table, r->r_action);
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res->r = policy;
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if (policy)
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atomic_inc(&policy->r_clntref);
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return 0;
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}
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if (err < 0 && err != -EAGAIN) {
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return err;
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}
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}
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FRprintk("FAILURE\n");
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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return -ENETUNREACH;
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}
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@ -414,20 +428,25 @@ rtattr_failure:
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return -1;
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}
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/* callers should hold rtnl semaphore */
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int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
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{
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int idx;
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int idx = 0;
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int s_idx = cb->args[0];
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struct fib_rule *r;
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struct hlist_node *node;
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rcu_read_lock();
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hlist_for_each_entry(r, node, &fib_rules, hlist) {
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read_lock(&fib_rules_lock);
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for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {
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if (idx < s_idx)
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continue;
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if (inet_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
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break;
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idx++;
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}
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read_unlock(&fib_rules_lock);
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rcu_read_unlock();
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cb->args[0] = idx;
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return skb->len;
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@ -435,5 +454,9 @@ int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
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void __init fib_rules_init(void)
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{
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INIT_HLIST_HEAD(&fib_rules);
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hlist_add_head(&local_rule.hlist, &fib_rules);
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hlist_add_after(&local_rule.hlist, &main_rule.hlist);
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hlist_add_after(&main_rule.hlist, &default_rule.hlist);
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register_netdevice_notifier(&fib_rules_notifier);
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}
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