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net: fib6: convert cfg metric to u32 outside of table write lock
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Do the nla validation earlier, outside the write lock.

This is needed by followup patch which needs to be able to call
request_module (which can sleep) if needed.

Joint work with Daniel Borkmann.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Florian Westphal authored and David S. Miller committed Jan 6, 2015
1 parent 0409c9a commit e715b6d
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Showing 3 changed files with 90 additions and 46 deletions.
10 changes: 7 additions & 3 deletions include/net/ip6_fib.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,11 @@ struct fib6_node {
#define FIB6_SUBTREE(fn) ((fn)->subtree)
#endif

struct mx6_config {
const u32 *mx;
DECLARE_BITMAP(mx_valid, RTAX_MAX);
};

/*
* routing information
*
Expand Down Expand Up @@ -291,9 +296,8 @@ struct fib6_node *fib6_locate(struct fib6_node *root,
void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
void *arg);

int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
struct nlattr *mx, int mx_len);

int fib6_add(struct fib6_node *root, struct rt6_info *rt,
struct nl_info *info, struct mx6_config *mxc);
int fib6_del(struct rt6_info *rt, struct nl_info *info);

void inet6_rt_notify(int event, struct rt6_info *rt, struct nl_info *info);
Expand Down
69 changes: 36 additions & 33 deletions net/ipv6/ip6_fib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -630,31 +630,35 @@ static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
RTF_GATEWAY;
}

static int fib6_commit_metrics(struct dst_entry *dst,
struct nlattr *mx, int mx_len)
static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
{
bool dst_host = dst->flags & DST_HOST;
struct nlattr *nla;
int remaining;
u32 *mp;
int i;

mp = dst_host ? dst_metrics_write_ptr(dst) :
kzalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
if (unlikely(!mp))
return -ENOMEM;
if (!dst_host)
dst_init_metrics(dst, mp, 0);
for (i = 0; i < RTAX_MAX; i++) {
if (test_bit(i, mxc->mx_valid))
mp[i] = mxc->mx[i];
}
}

static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
{
if (!mxc->mx)
return 0;

nla_for_each_attr(nla, mx, mx_len, remaining) {
int type = nla_type(nla);
if (dst->flags & DST_HOST) {
u32 *mp = dst_metrics_write_ptr(dst);

if (type) {
if (type > RTAX_MAX)
return -EINVAL;
if (unlikely(!mp))
return -ENOMEM;

mp[type - 1] = nla_get_u32(nla);
}
fib6_copy_metrics(mp, mxc);
} else {
dst_init_metrics(dst, mxc->mx, false);

/* We've stolen mx now. */
mxc->mx = NULL;
}

return 0;
}

Expand All @@ -663,7 +667,7 @@ static int fib6_commit_metrics(struct dst_entry *dst,
*/

static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
struct nl_info *info, struct nlattr *mx, int mx_len)
struct nl_info *info, struct mx6_config *mxc)
{
struct rt6_info *iter = NULL;
struct rt6_info **ins;
Expand Down Expand Up @@ -772,11 +776,10 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
pr_warn("NLM_F_CREATE should be set when creating new route\n");

add:
if (mx) {
err = fib6_commit_metrics(&rt->dst, mx, mx_len);
if (err)
return err;
}
err = fib6_commit_metrics(&rt->dst, mxc);
if (err)
return err;

rt->dst.rt6_next = iter;
*ins = rt;
rt->rt6i_node = fn;
Expand All @@ -796,11 +799,11 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
return -ENOENT;
}
if (mx) {
err = fib6_commit_metrics(&rt->dst, mx, mx_len);
if (err)
return err;
}

err = fib6_commit_metrics(&rt->dst, mxc);
if (err)
return err;

*ins = rt;
rt->rt6i_node = fn;
rt->dst.rt6_next = iter->dst.rt6_next;
Expand Down Expand Up @@ -837,8 +840,8 @@ void fib6_force_start_gc(struct net *net)
* with source addr info in sub-trees
*/

int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
struct nlattr *mx, int mx_len)
int fib6_add(struct fib6_node *root, struct rt6_info *rt,
struct nl_info *info, struct mx6_config *mxc)
{
struct fib6_node *fn, *pn = NULL;
int err = -ENOMEM;
Expand Down Expand Up @@ -933,7 +936,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
}
#endif

err = fib6_add_rt2node(fn, rt, info, mx, mx_len);
err = fib6_add_rt2node(fn, rt, info, mxc);
if (!err) {
fib6_start_gc(info->nl_net, rt);
if (!(rt->rt6i_flags & RTF_CACHE))
Expand Down
57 changes: 47 additions & 10 deletions net/ipv6/route.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -853,25 +853,25 @@ EXPORT_SYMBOL(rt6_lookup);
*/

static int __ip6_ins_rt(struct rt6_info *rt, struct nl_info *info,
struct nlattr *mx, int mx_len)
struct mx6_config *mxc)
{
int err;
struct fib6_table *table;

table = rt->rt6i_table;
write_lock_bh(&table->tb6_lock);
err = fib6_add(&table->tb6_root, rt, info, mx, mx_len);
err = fib6_add(&table->tb6_root, rt, info, mxc);
write_unlock_bh(&table->tb6_lock);

return err;
}

int ip6_ins_rt(struct rt6_info *rt)
{
struct nl_info info = {
.nl_net = dev_net(rt->dst.dev),
};
return __ip6_ins_rt(rt, &info, NULL, 0);
struct nl_info info = { .nl_net = dev_net(rt->dst.dev), };
struct mx6_config mxc = { .mx = NULL, };

return __ip6_ins_rt(rt, &info, &mxc);
}

static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
Expand Down Expand Up @@ -1470,9 +1470,39 @@ static int ip6_dst_gc(struct dst_ops *ops)
return entries > rt_max_size;
}

/*
*
*/
static int ip6_convert_metrics(struct mx6_config *mxc,
const struct fib6_config *cfg)
{
struct nlattr *nla;
int remaining;
u32 *mp;

if (cfg->fc_mx == NULL)
return 0;

mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
if (unlikely(!mp))
return -ENOMEM;

nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
int type = nla_type(nla);

if (type) {
if (unlikely(type > RTAX_MAX))
goto err;

mp[type - 1] = nla_get_u32(nla);
__set_bit(type - 1, mxc->mx_valid);
}
}

mxc->mx = mp;

return 0;
err:
kfree(mp);
return -EINVAL;
}

int ip6_route_add(struct fib6_config *cfg)
{
Expand All @@ -1482,6 +1512,7 @@ int ip6_route_add(struct fib6_config *cfg)
struct net_device *dev = NULL;
struct inet6_dev *idev = NULL;
struct fib6_table *table;
struct mx6_config mxc = { .mx = NULL, };
int addr_type;

if (cfg->fc_dst_len > 128 || cfg->fc_src_len > 128)
Expand Down Expand Up @@ -1677,8 +1708,14 @@ int ip6_route_add(struct fib6_config *cfg)

cfg->fc_nlinfo.nl_net = dev_net(dev);

return __ip6_ins_rt(rt, &cfg->fc_nlinfo, cfg->fc_mx, cfg->fc_mx_len);
err = ip6_convert_metrics(&mxc, cfg);
if (err)
goto out;

err = __ip6_ins_rt(rt, &cfg->fc_nlinfo, &mxc);

kfree(mxc.mx);
return err;
out:
if (dev)
dev_put(dev);
Expand Down

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