From: David Ahern <dsah...@gmail.com>
Add support for atomically upating a nexthop config.
When updating a nexthop, walk the lists of associated fib entries and
verify the new config is valid. After replace, bump the sequence counters
for FIB entries to invalidate any dst entries.
Signed-off-by: David Ahern <dsah...@gmail.com>
---
net/ipv4/nexthop.c | 244 +++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 227 insertions(+), 17 deletions(-)
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 6d1c8927e6d3..92aeff6ffe26 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -17,7 +17,7 @@
#include <net/sock.h>
static void remove_nexthop(struct net *net, struct nexthop *nh,
- struct nl_info *nlinfo);
+ bool skip_fib, struct nl_info *nlinfo);
#define NH_DEV_HASHBITS 8
#define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS)
@@ -548,6 +548,16 @@ int nexthop_for_each_fib6_nh(struct nexthop *nh,
}
EXPORT_SYMBOL_GPL(nexthop_for_each_fib6_nh);
+static int check_src_addr(const struct in6_addr *saddr,
+ struct netlink_ext_ack *extack)
+{
+ if (!ipv6_addr_any(saddr)) {
+ NL_SET_ERR_MSG(extack, "IPv6 routes using source address can
not use nexthop objects");
+ return -EINVAL;
+ }
+ return 0;
+}
+
int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
struct netlink_ext_ack *extack)
{
@@ -559,10 +569,8 @@ int fib6_check_nexthop(struct nexthop *nh, struct
fib6_config *cfg,
* routing it can not use nexthop objects. mlxsw also does not allow
* fib6_src on routes.
*/
- if (!ipv6_addr_any(&cfg->fc_src)) {
- NL_SET_ERR_MSG(extack, "IPv6 routes using source address can
not use nexthop objects");
+ if (cfg && check_src_addr(&cfg->fc_src, extack) < 0)
return -EINVAL;
- }
if (nh->is_group) {
struct nh_group *nhg;
@@ -583,6 +591,25 @@ int fib6_check_nexthop(struct nexthop *nh, struct
fib6_config *cfg,
}
EXPORT_SYMBOL_GPL(fib6_check_nexthop);
+/* if existing nexthop has ipv6 routes linked to it, need
+ * to verify this new spec works with ipv6
+ */
+static int fib6_check_nh_list(struct nexthop *old, struct nexthop *new,
+ struct netlink_ext_ack *extack)
+{
+ struct fib6_info *f6i;
+
+ if (list_empty(&old->f6i_list))
+ return 0;
+
+ list_for_each_entry(f6i, &old->f6i_list, nh_list) {
+ if (check_src_addr(&f6i->fib6_src.addr, extack) < 0)
+ return -EINVAL;
+ }
+
+ return fib6_check_nexthop(new, NULL, extack);
+}
+
static int nexthop_check_scope(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
@@ -631,6 +658,21 @@ int fib_check_nexthop(struct nexthop *nh, u8 scope,
return err;
}
+static int fib_check_nh_list(struct nexthop *old, struct nexthop *new,
+ struct netlink_ext_ack *extack)
+{
+ struct fib_info *fi;
+
+ list_for_each_entry(fi, &old->fi_list, nh_list) {
+ int err;
+
+ err = fib_check_nexthop(new, fi->fib_scope, extack);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
static void nh_group_rebalance(struct nh_group *nhg)
{
int total = 0;
@@ -688,7 +730,7 @@ static void remove_nh_grp_entry(struct nh_grp_entry *nhge,
}
static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh,
- struct nl_info *nlinfo)
+ bool skip_fib, struct nl_info *nlinfo)
{
struct nh_grp_entry *nhge, *tmp;
@@ -701,7 +743,7 @@ static void remove_nexthop_from_groups(struct net *net,
struct nexthop *nh,
/* if this group has no more entries then remove it */
if (!nhg->num_nh)
- remove_nexthop(net, nhge->nh_parent, nlinfo);
+ remove_nexthop(net, nhge->nh_parent, skip_fib, nlinfo);
}
}
@@ -723,6 +765,7 @@ static void remove_nexthop_group(struct nexthop *nh, struct
nl_info *nlinfo)
}
}
+/* not called for nexthop replace */
static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
{
struct fib6_info *f6i, *tmp;
@@ -745,9 +788,10 @@ static void __remove_nexthop_fib(struct net *net, struct
nexthop *nh)
}
static void __remove_nexthop(struct net *net, struct nexthop *nh,
- struct nl_info *nlinfo)
+ bool skip_fib, struct nl_info *nlinfo)
{
- __remove_nexthop_fib(net, nh);
+ if (!skip_fib)
+ __remove_nexthop_fib(net, nh);
if (nh->is_group) {
remove_nexthop_group(nh, nlinfo);
@@ -758,12 +802,12 @@ static void __remove_nexthop(struct net *net, struct
nexthop *nh,
if (nhi->fib_nhc.nhc_dev)
hlist_del(&nhi->dev_hash);
- remove_nexthop_from_groups(net, nh, nlinfo);
+ remove_nexthop_from_groups(net, nh, skip_fib, nlinfo);
}
}
static void remove_nexthop(struct net *net, struct nexthop *nh,
- struct nl_info *nlinfo)
+ bool skip_fib, struct nl_info *nlinfo)
{
/* remove from the tree */
rb_erase(&nh->rb_node, &net->nexthop.rb_root);
@@ -771,16 +815,177 @@ static void remove_nexthop(struct net *net, struct
nexthop *nh,
if (nlinfo)
nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
- __remove_nexthop(net, nh, nlinfo);
+ __remove_nexthop(net, nh, skip_fib, nlinfo);
nh_base_seq_inc(net);
nexthop_put(nh);
}
+/* if any FIB entries reference this nexthop, any dst entries
+ * need to be regenerated
+ */
+static void nh_rt_cache_flush(struct net *net, struct nexthop *nh)
+{
+ struct fib6_info *f6i;
+
+ if (!list_empty(&nh->fi_list))
+ rt_cache_flush(net);
+
+ list_for_each_entry(f6i, &nh->f6i_list, nh_list)
+ ipv6_stub->fib6_update_sernum(net, f6i);
+}
+
+static int replace_nexthop_grp(struct net *net, struct nexthop *old,
+ struct nexthop *new,
+ struct netlink_ext_ack *extack)
+{
+ struct nh_group *oldg, *newg;
+ int i;
+
+ if (!new->is_group) {
+ NL_SET_ERR_MSG(extack, "Can not replace a nexthop group with a
nexthop.");
+ return -EINVAL;
+ }
+
+ oldg = rtnl_dereference(old->nh_grp);
+ newg = rtnl_dereference(new->nh_grp);
+
+ /* update parents - used by nexthop code for cleanup */
+ for (i = 0; i < newg->num_nh; ++i)
+ newg->nh_entries[i].nh_parent = old;
+
+ rcu_assign_pointer(old->nh_grp, newg);
+
+ for (i = 0; i < oldg->num_nh; ++i)
+ oldg->nh_entries[i].nh_parent = new;
+
+ rcu_assign_pointer(new->nh_grp, oldg);
+
+ return 0;
+}
+
+static int replace_nexthop_single(struct net *net, struct nexthop *old,
+ struct nexthop *new,
+ struct netlink_ext_ack *extack)
+{
+ struct nh_info *oldi, *newi;
+
+ if (new->is_group) {
+ NL_SET_ERR_MSG(extack, "Can not replace a nexthop with a
nexthop group.");
+ return -EINVAL;
+ }
+
+ oldi = rtnl_dereference(old->nh_info);
+ newi = rtnl_dereference(new->nh_info);
+
+ newi->nh_parent = old;
+ oldi->nh_parent = new;
+
+ old->protocol = new->protocol;
+ old->nh_flags = new->nh_flags;
+
+ rcu_assign_pointer(old->nh_info, newi);
+ rcu_assign_pointer(new->nh_info, oldi);
+
+ return 0;
+}
+
+static void __nexthop_replace_notify(struct net *net, struct nexthop *nh,
+ struct nl_info *info)
+{
+ struct fib6_info *f6i;
+
+ if (!list_empty(&nh->fi_list)) {
+ struct fib_info *fi;
+
+ /* expectation is a few fib_info per nexthop and then
+ * a lot of routes per fib_info. So mark the fib_info
+ * and then walk the fib tables once
+ */
+ list_for_each_entry(fi, &nh->fi_list, nh_list)
+ fi->nh_updated = true;
+
+ fib_info_notify_update(net, info);
+
+ list_for_each_entry(fi, &nh->fi_list, nh_list)
+ fi->nh_updated = false;
+ }
+
+ list_for_each_entry(f6i, &nh->f6i_list, nh_list)
+ ipv6_stub->fib6_rt_update(net, f6i, info);
+}
+
+/* send RTM_NEWROUTE with REPLACE flag set for all FIB entries
+ * linked to this nexthop and for all groups that the nexthop
+ * is a member of
+ */
+static void nexthop_replace_notify(struct net *net, struct nexthop *nh,
+ struct nl_info *info)
+{
+ struct nh_grp_entry *nhge;
+
+ __nexthop_replace_notify(net, nh, info);
+
+ list_for_each_entry(nhge, &nh->grp_list, nh_list)
+ __nexthop_replace_notify(net, nhge->nh_parent, info);
+}
+
static int replace_nexthop(struct net *net, struct nexthop *old,
struct nexthop *new, struct netlink_ext_ack *extack)
{
- return -EEXIST;
+ bool new_is_reject = false;
+ struct nh_grp_entry *nhge;
+ int err;
+
+ /* check that existing FIB entries are ok with the
+ * new nexthop definition
+ */
+ err = fib_check_nh_list(old, new, extack);
+ if (err)
+ return err;
+
+ err = fib6_check_nh_list(old, new, extack);
+ if (err)
+ return err;
+
+ if (!new->is_group) {
+ struct nh_info *nhi = rtnl_dereference(new->nh_info);
+
+ new_is_reject = nhi->reject_nh;
+ }
+
+ list_for_each_entry(nhge, &old->grp_list, nh_list) {
+ /* if new nexthop is a blackhole, any groups using this
+ * nexthop cannot have more than 1 path
+ */
+ if (new_is_reject &&
+ nexthop_num_path(nhge->nh_parent) > 1) {
+ NL_SET_ERR_MSG(extack, "Blackhole nexthop can not be a
member of a group with more than one path");
+ return -EINVAL;
+ }
+
+ err = fib_check_nh_list(nhge->nh_parent, new, extack);
+ if (err)
+ return err;
+
+ err = fib6_check_nh_list(nhge->nh_parent, new, extack);
+ if (err)
+ return err;
+ }
+
+ if (old->is_group)
+ err = replace_nexthop_grp(net, old, new, extack);
+ else
+ err = replace_nexthop_single(net, old, new, extack);
+
+ if (!err) {
+ nh_rt_cache_flush(net, old);
+
+ __remove_nexthop(net, new, true, NULL);
+ nexthop_put(new);
+ }
+
+ return err;
}
/* called with rtnl_lock held */
@@ -792,6 +997,7 @@ static int insert_nexthop(struct net *net, struct nexthop
*new_nh,
bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
bool create = !!(cfg->nlflags & NLM_F_CREATE);
u32 new_id = new_nh->id;
+ int replace_notify = 0;
int rc = -EEXIST;
pp = &root->rb_node;
@@ -811,8 +1017,10 @@ static int insert_nexthop(struct net *net, struct nexthop
*new_nh,
pp = &next->rb_right;
} else if (replace) {
rc = replace_nexthop(net, nh, new_nh, extack);
- if (!rc)
+ if (!rc) {
new_nh = nh; /* send notification with old nh */
+ replace_notify = 1;
+ }
goto out;
} else {
/* id already exists and not a replace */
@@ -833,6 +1041,8 @@ static int insert_nexthop(struct net *net, struct nexthop
*new_nh,
if (!rc) {
nh_base_seq_inc(net);
nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
+ if (replace_notify)
+ nexthop_replace_notify(net, new_nh, &cfg->nlinfo);
}
return rc;
@@ -852,7 +1062,7 @@ static void nexthop_flush_dev(struct net_device *dev)
if (nhi->fib_nhc.nhc_dev != dev)
continue;
- remove_nexthop(net, nhi->nh_parent, NULL);
+ remove_nexthop(net, nhi->nh_parent, false, NULL);
}
}
@@ -865,7 +1075,7 @@ static void flush_all_nexthops(struct net *net)
while ((node = rb_first(root))) {
nh = rb_entry(node, struct nexthop, rb_node);
- remove_nexthop(net, nh, NULL);
+ remove_nexthop(net, nh, false, NULL);
cond_resched();
}
}
@@ -1079,7 +1289,7 @@ static struct nexthop *nexthop_add(struct net *net,
struct nh_config *cfg,
err = insert_nexthop(net, nh, cfg, extack);
if (err) {
- __remove_nexthop(net, nh, NULL);
+ __remove_nexthop(net, nh, false, NULL);
nexthop_put(nh);
nh = ERR_PTR(err);
}
@@ -1339,7 +1549,7 @@ static int rtm_del_nexthop(struct sk_buff *skb, struct
nlmsghdr *nlh,
if (!nh)
return -ENOENT;
- remove_nexthop(net, nh, &nlinfo);
+ remove_nexthop(net, nh, false, &nlinfo);
return 0;
}
--
2.11.0
