linux/net/ipv4/nexthop.c
David Ahern f88d8ea67f ipv6: Plumb support for nexthop object in a fib6_info
Add struct nexthop and nh_list list_head to fib6_info. nh_list is the
fib6_info side of the nexthop <-> fib_info relationship. Since a fib6_info
referencing a nexthop object can not have 'sibling' entries (the old way
of doing multipath routes), the nh_list is a union with fib6_siblings.

Add f6i_list list_head to 'struct nexthop' to track fib6_info entries
using a nexthop instance. Update __remove_nexthop_fib to walk f6_list
and delete fib entries using the nexthop.

Add a few nexthop helpers for use when a nexthop is added to fib6_info:
- nexthop_fib6_nh - return first fib6_nh in a nexthop object
- fib6_info_nh_dev moved to nexthop.h and updated to use nexthop_fib6_nh
  if the fib6_info references a nexthop object
- nexthop_path_fib6_result - similar to ipv4, select a path within a
  multipath nexthop object. If the nexthop is a blackhole, set
  fib6_result type to RTN_BLACKHOLE, and set the REJECT flag

Update the fib6_info references to check for nh and take a different path
as needed:
- rt6_qualify_for_ecmp - if a fib entry uses a nexthop object it can NOT
  be coalesced with other fib entries into a multipath route
- rt6_duplicate_nexthop - use nexthop_cmp if either fib6_info references
  a nexthop
- addrconf (host routes), RA's and info entries (anything configured via
  ndisc) does not use nexthop objects
- fib6_info_destroy_rcu - put reference to nexthop object
- fib6_purge_rt - drop fib6_info from f6i_list
- fib6_select_path - update to use the new nexthop_path_fib6_result when
  fib entry uses a nexthop object
- rt6_device_match - update to catch use of nexthop object as a blackhole
  and set fib6_type and flags.
- ip6_route_info_create - don't add space for fib6_nh if fib entry is
  going to reference a nexthop object, take a reference to nexthop object,
  disallow use of source routing
- rt6_nlmsg_size - add space for RTA_NH_ID
- add rt6_fill_node_nexthop to add nexthop data on a dump

As with ipv4, most of the changes push existing code into the else branch
of whether the fib entry uses a nexthop object.

Update the nexthop code to walk f6i_list on a nexthop deleted to remove
fib entries referencing it.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-04 19:26:50 -07:00

1589 lines
35 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Generic nexthop implementation
*
* Copyright (c) 2017-19 Cumulus Networks
* Copyright (c) 2017-19 David Ahern <dsa@cumulusnetworks.com>
*/
#include <linux/nexthop.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>
#include <net/arp.h>
#include <net/ipv6_stubs.h>
#include <net/lwtunnel.h>
#include <net/ndisc.h>
#include <net/nexthop.h>
#include <net/route.h>
#include <net/sock.h>
static void remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo);
#define NH_DEV_HASHBITS 8
#define NH_DEV_HASHSIZE (1U << NH_DEV_HASHBITS)
static const struct nla_policy rtm_nh_policy[NHA_MAX + 1] = {
[NHA_UNSPEC] = { .strict_start_type = NHA_UNSPEC + 1 },
[NHA_ID] = { .type = NLA_U32 },
[NHA_GROUP] = { .type = NLA_BINARY },
[NHA_GROUP_TYPE] = { .type = NLA_U16 },
[NHA_BLACKHOLE] = { .type = NLA_FLAG },
[NHA_OIF] = { .type = NLA_U32 },
[NHA_GATEWAY] = { .type = NLA_BINARY },
[NHA_ENCAP_TYPE] = { .type = NLA_U16 },
[NHA_ENCAP] = { .type = NLA_NESTED },
[NHA_GROUPS] = { .type = NLA_FLAG },
[NHA_MASTER] = { .type = NLA_U32 },
};
static unsigned int nh_dev_hashfn(unsigned int val)
{
unsigned int mask = NH_DEV_HASHSIZE - 1;
return (val ^
(val >> NH_DEV_HASHBITS) ^
(val >> (NH_DEV_HASHBITS * 2))) & mask;
}
static void nexthop_devhash_add(struct net *net, struct nh_info *nhi)
{
struct net_device *dev = nhi->fib_nhc.nhc_dev;
struct hlist_head *head;
unsigned int hash;
WARN_ON(!dev);
hash = nh_dev_hashfn(dev->ifindex);
head = &net->nexthop.devhash[hash];
hlist_add_head(&nhi->dev_hash, head);
}
static void nexthop_free_mpath(struct nexthop *nh)
{
struct nh_group *nhg;
int i;
nhg = rcu_dereference_raw(nh->nh_grp);
for (i = 0; i < nhg->num_nh; ++i)
WARN_ON(nhg->nh_entries[i].nh);
kfree(nhg);
}
static void nexthop_free_single(struct nexthop *nh)
{
struct nh_info *nhi;
nhi = rcu_dereference_raw(nh->nh_info);
switch (nhi->family) {
case AF_INET:
fib_nh_release(nh->net, &nhi->fib_nh);
break;
case AF_INET6:
ipv6_stub->fib6_nh_release(&nhi->fib6_nh);
break;
}
kfree(nhi);
}
void nexthop_free_rcu(struct rcu_head *head)
{
struct nexthop *nh = container_of(head, struct nexthop, rcu);
if (nh->is_group)
nexthop_free_mpath(nh);
else
nexthop_free_single(nh);
kfree(nh);
}
EXPORT_SYMBOL_GPL(nexthop_free_rcu);
static struct nexthop *nexthop_alloc(void)
{
struct nexthop *nh;
nh = kzalloc(sizeof(struct nexthop), GFP_KERNEL);
if (nh) {
INIT_LIST_HEAD(&nh->fi_list);
INIT_LIST_HEAD(&nh->f6i_list);
INIT_LIST_HEAD(&nh->grp_list);
}
return nh;
}
static struct nh_group *nexthop_grp_alloc(u16 num_nh)
{
size_t sz = offsetof(struct nexthop, nh_grp)
+ sizeof(struct nh_group)
+ sizeof(struct nh_grp_entry) * num_nh;
struct nh_group *nhg;
nhg = kzalloc(sz, GFP_KERNEL);
if (nhg)
nhg->num_nh = num_nh;
return nhg;
}
static void nh_base_seq_inc(struct net *net)
{
while (++net->nexthop.seq == 0)
;
}
/* no reference taken; rcu lock or rtnl must be held */
struct nexthop *nexthop_find_by_id(struct net *net, u32 id)
{
struct rb_node **pp, *parent = NULL, *next;
pp = &net->nexthop.rb_root.rb_node;
while (1) {
struct nexthop *nh;
next = rcu_dereference_raw(*pp);
if (!next)
break;
parent = next;
nh = rb_entry(parent, struct nexthop, rb_node);
if (id < nh->id)
pp = &next->rb_left;
else if (id > nh->id)
pp = &next->rb_right;
else
return nh;
}
return NULL;
}
EXPORT_SYMBOL_GPL(nexthop_find_by_id);
/* used for auto id allocation; called with rtnl held */
static u32 nh_find_unused_id(struct net *net)
{
u32 id_start = net->nexthop.last_id_allocated;
while (1) {
net->nexthop.last_id_allocated++;
if (net->nexthop.last_id_allocated == id_start)
break;
if (!nexthop_find_by_id(net, net->nexthop.last_id_allocated))
return net->nexthop.last_id_allocated;
}
return 0;
}
static int nla_put_nh_group(struct sk_buff *skb, struct nh_group *nhg)
{
struct nexthop_grp *p;
size_t len = nhg->num_nh * sizeof(*p);
struct nlattr *nla;
u16 group_type = 0;
int i;
if (nhg->mpath)
group_type = NEXTHOP_GRP_TYPE_MPATH;
if (nla_put_u16(skb, NHA_GROUP_TYPE, group_type))
goto nla_put_failure;
nla = nla_reserve(skb, NHA_GROUP, len);
if (!nla)
goto nla_put_failure;
p = nla_data(nla);
for (i = 0; i < nhg->num_nh; ++i) {
p->id = nhg->nh_entries[i].nh->id;
p->weight = nhg->nh_entries[i].weight - 1;
p += 1;
}
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int nh_fill_node(struct sk_buff *skb, struct nexthop *nh,
int event, u32 portid, u32 seq, unsigned int nlflags)
{
struct fib6_nh *fib6_nh;
struct fib_nh *fib_nh;
struct nlmsghdr *nlh;
struct nh_info *nhi;
struct nhmsg *nhm;
nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nhm), nlflags);
if (!nlh)
return -EMSGSIZE;
nhm = nlmsg_data(nlh);
nhm->nh_family = AF_UNSPEC;
nhm->nh_flags = nh->nh_flags;
nhm->nh_protocol = nh->protocol;
nhm->nh_scope = 0;
nhm->resvd = 0;
if (nla_put_u32(skb, NHA_ID, nh->id))
goto nla_put_failure;
if (nh->is_group) {
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
if (nla_put_nh_group(skb, nhg))
goto nla_put_failure;
goto out;
}
nhi = rtnl_dereference(nh->nh_info);
nhm->nh_family = nhi->family;
if (nhi->reject_nh) {
if (nla_put_flag(skb, NHA_BLACKHOLE))
goto nla_put_failure;
goto out;
} else {
const struct net_device *dev;
dev = nhi->fib_nhc.nhc_dev;
if (dev && nla_put_u32(skb, NHA_OIF, dev->ifindex))
goto nla_put_failure;
}
nhm->nh_scope = nhi->fib_nhc.nhc_scope;
switch (nhi->family) {
case AF_INET:
fib_nh = &nhi->fib_nh;
if (fib_nh->fib_nh_gw_family &&
nla_put_u32(skb, NHA_GATEWAY, fib_nh->fib_nh_gw4))
goto nla_put_failure;
break;
case AF_INET6:
fib6_nh = &nhi->fib6_nh;
if (fib6_nh->fib_nh_gw_family &&
nla_put_in6_addr(skb, NHA_GATEWAY, &fib6_nh->fib_nh_gw6))
goto nla_put_failure;
break;
}
if (nhi->fib_nhc.nhc_lwtstate &&
lwtunnel_fill_encap(skb, nhi->fib_nhc.nhc_lwtstate,
NHA_ENCAP, NHA_ENCAP_TYPE) < 0)
goto nla_put_failure;
out:
nlmsg_end(skb, nlh);
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static size_t nh_nlmsg_size_grp(struct nexthop *nh)
{
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
size_t sz = sizeof(struct nexthop_grp) * nhg->num_nh;
return nla_total_size(sz) +
nla_total_size(2); /* NHA_GROUP_TYPE */
}
static size_t nh_nlmsg_size_single(struct nexthop *nh)
{
struct nh_info *nhi = rtnl_dereference(nh->nh_info);
size_t sz;
/* covers NHA_BLACKHOLE since NHA_OIF and BLACKHOLE
* are mutually exclusive
*/
sz = nla_total_size(4); /* NHA_OIF */
switch (nhi->family) {
case AF_INET:
if (nhi->fib_nh.fib_nh_gw_family)
sz += nla_total_size(4); /* NHA_GATEWAY */
break;
case AF_INET6:
/* NHA_GATEWAY */
if (nhi->fib6_nh.fib_nh_gw_family)
sz += nla_total_size(sizeof(const struct in6_addr));
break;
}
if (nhi->fib_nhc.nhc_lwtstate) {
sz += lwtunnel_get_encap_size(nhi->fib_nhc.nhc_lwtstate);
sz += nla_total_size(2); /* NHA_ENCAP_TYPE */
}
return sz;
}
static size_t nh_nlmsg_size(struct nexthop *nh)
{
size_t sz = nla_total_size(4); /* NHA_ID */
if (nh->is_group)
sz += nh_nlmsg_size_grp(nh);
else
sz += nh_nlmsg_size_single(nh);
return sz;
}
static void nexthop_notify(int event, struct nexthop *nh, struct nl_info *info)
{
unsigned int nlflags = info->nlh ? info->nlh->nlmsg_flags : 0;
u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
struct sk_buff *skb;
int err = -ENOBUFS;
skb = nlmsg_new(nh_nlmsg_size(nh), gfp_any());
if (!skb)
goto errout;
err = nh_fill_node(skb, nh, event, info->portid, seq, nlflags);
if (err < 0) {
/* -EMSGSIZE implies BUG in nh_nlmsg_size() */
WARN_ON(err == -EMSGSIZE);
kfree_skb(skb);
goto errout;
}
rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_NEXTHOP,
info->nlh, gfp_any());
return;
errout:
if (err < 0)
rtnl_set_sk_err(info->nl_net, RTNLGRP_NEXTHOP, err);
}
static bool valid_group_nh(struct nexthop *nh, unsigned int npaths,
struct netlink_ext_ack *extack)
{
if (nh->is_group) {
struct nh_group *nhg = rtnl_dereference(nh->nh_grp);
/* nested multipath (group within a group) is not
* supported
*/
if (nhg->mpath) {
NL_SET_ERR_MSG(extack,
"Multipath group can not be a nexthop within a group");
return false;
}
} else {
struct nh_info *nhi = rtnl_dereference(nh->nh_info);
if (nhi->reject_nh && npaths > 1) {
NL_SET_ERR_MSG(extack,
"Blackhole nexthop can not be used in a group with more than 1 path");
return false;
}
}
return true;
}
static int nh_check_attr_group(struct net *net, struct nlattr *tb[],
struct netlink_ext_ack *extack)
{
unsigned int len = nla_len(tb[NHA_GROUP]);
struct nexthop_grp *nhg;
unsigned int i, j;
if (len & (sizeof(struct nexthop_grp) - 1)) {
NL_SET_ERR_MSG(extack,
"Invalid length for nexthop group attribute");
return -EINVAL;
}
/* convert len to number of nexthop ids */
len /= sizeof(*nhg);
nhg = nla_data(tb[NHA_GROUP]);
for (i = 0; i < len; ++i) {
if (nhg[i].resvd1 || nhg[i].resvd2) {
NL_SET_ERR_MSG(extack, "Reserved fields in nexthop_grp must be 0");
return -EINVAL;
}
if (nhg[i].weight > 254) {
NL_SET_ERR_MSG(extack, "Invalid value for weight");
return -EINVAL;
}
for (j = i + 1; j < len; ++j) {
if (nhg[i].id == nhg[j].id) {
NL_SET_ERR_MSG(extack, "Nexthop id can not be used twice in a group");
return -EINVAL;
}
}
}
nhg = nla_data(tb[NHA_GROUP]);
for (i = 0; i < len; ++i) {
struct nexthop *nh;
nh = nexthop_find_by_id(net, nhg[i].id);
if (!nh) {
NL_SET_ERR_MSG(extack, "Invalid nexthop id");
return -EINVAL;
}
if (!valid_group_nh(nh, len, extack))
return -EINVAL;
}
for (i = NHA_GROUP + 1; i < __NHA_MAX; ++i) {
if (!tb[i])
continue;
NL_SET_ERR_MSG(extack,
"No other attributes can be set in nexthop groups");
return -EINVAL;
}
return 0;
}
static bool ipv6_good_nh(const struct fib6_nh *nh)
{
int state = NUD_REACHABLE;
struct neighbour *n;
rcu_read_lock_bh();
n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6);
if (n)
state = n->nud_state;
rcu_read_unlock_bh();
return !!(state & NUD_VALID);
}
static bool ipv4_good_nh(const struct fib_nh *nh)
{
int state = NUD_REACHABLE;
struct neighbour *n;
rcu_read_lock_bh();
n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
(__force u32)nh->fib_nh_gw4);
if (n)
state = n->nud_state;
rcu_read_unlock_bh();
return !!(state & NUD_VALID);
}
struct nexthop *nexthop_select_path(struct nexthop *nh, int hash)
{
struct nexthop *rc = NULL;
struct nh_group *nhg;
int i;
if (!nh->is_group)
return nh;
nhg = rcu_dereference(nh->nh_grp);
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
struct nh_info *nhi;
if (hash > atomic_read(&nhge->upper_bound))
continue;
/* nexthops always check if it is good and does
* not rely on a sysctl for this behavior
*/
nhi = rcu_dereference(nhge->nh->nh_info);
switch (nhi->family) {
case AF_INET:
if (ipv4_good_nh(&nhi->fib_nh))
return nhge->nh;
break;
case AF_INET6:
if (ipv6_good_nh(&nhi->fib6_nh))
return nhge->nh;
break;
}
if (!rc)
rc = nhge->nh;
}
return rc;
}
EXPORT_SYMBOL_GPL(nexthop_select_path);
int fib6_check_nexthop(struct nexthop *nh, struct fib6_config *cfg,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
/* fib6_src is unique to a fib6_info and limits the ability to cache
* routes in fib6_nh within a nexthop that is potentially shared
* across multiple fib entries. If the config wants to use source
* 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");
return -EINVAL;
}
if (nh->is_group) {
struct nh_group *nhg;
nhg = rtnl_dereference(nh->nh_grp);
if (nhg->has_v4)
goto no_v4_nh;
} else {
nhi = rtnl_dereference(nh->nh_info);
if (nhi->family == AF_INET)
goto no_v4_nh;
}
return 0;
no_v4_nh:
NL_SET_ERR_MSG(extack, "IPv6 routes can not use an IPv4 nexthop");
return -EINVAL;
}
EXPORT_SYMBOL_GPL(fib6_check_nexthop);
static int nexthop_check_scope(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
nhi = rtnl_dereference(nh->nh_info);
if (scope == RT_SCOPE_HOST && nhi->fib_nhc.nhc_gw_family) {
NL_SET_ERR_MSG(extack,
"Route with host scope can not have a gateway");
return -EINVAL;
}
if (nhi->fib_nhc.nhc_flags & RTNH_F_ONLINK && scope >= RT_SCOPE_LINK) {
NL_SET_ERR_MSG(extack, "Scope mismatch with nexthop");
return -EINVAL;
}
return 0;
}
/* Invoked by fib add code to verify nexthop by id is ok with
* config for prefix; parts of fib_check_nh not done when nexthop
* object is used.
*/
int fib_check_nexthop(struct nexthop *nh, u8 scope,
struct netlink_ext_ack *extack)
{
int err = 0;
if (nh->is_group) {
struct nh_group *nhg;
if (scope == RT_SCOPE_HOST) {
NL_SET_ERR_MSG(extack, "Route with host scope can not have multiple nexthops");
err = -EINVAL;
goto out;
}
nhg = rtnl_dereference(nh->nh_grp);
/* all nexthops in a group have the same scope */
err = nexthop_check_scope(nhg->nh_entries[0].nh, scope, extack);
} else {
err = nexthop_check_scope(nh, scope, extack);
}
out:
return err;
}
static void nh_group_rebalance(struct nh_group *nhg)
{
int total = 0;
int w = 0;
int i;
for (i = 0; i < nhg->num_nh; ++i)
total += nhg->nh_entries[i].weight;
for (i = 0; i < nhg->num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
int upper_bound;
w += nhge->weight;
upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31, total) - 1;
atomic_set(&nhge->upper_bound, upper_bound);
}
}
static void remove_nh_grp_entry(struct nh_grp_entry *nhge,
struct nh_group *nhg,
struct nl_info *nlinfo)
{
struct nexthop *nh = nhge->nh;
struct nh_grp_entry *nhges;
bool found = false;
int i;
WARN_ON(!nh);
nhges = nhg->nh_entries;
for (i = 0; i < nhg->num_nh; ++i) {
if (found) {
nhges[i-1].nh = nhges[i].nh;
nhges[i-1].weight = nhges[i].weight;
list_del(&nhges[i].nh_list);
list_add(&nhges[i-1].nh_list, &nhges[i-1].nh->grp_list);
} else if (nhg->nh_entries[i].nh == nh) {
found = true;
}
}
if (WARN_ON(!found))
return;
nhg->num_nh--;
nhg->nh_entries[nhg->num_nh].nh = NULL;
nh_group_rebalance(nhg);
nexthop_put(nh);
if (nlinfo)
nexthop_notify(RTM_NEWNEXTHOP, nhge->nh_parent, nlinfo);
}
static void remove_nexthop_from_groups(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
struct nh_grp_entry *nhge, *tmp;
list_for_each_entry_safe(nhge, tmp, &nh->grp_list, nh_list) {
struct nh_group *nhg;
list_del(&nhge->nh_list);
nhg = rtnl_dereference(nhge->nh_parent->nh_grp);
remove_nh_grp_entry(nhge, nhg, nlinfo);
/* if this group has no more entries then remove it */
if (!nhg->num_nh)
remove_nexthop(net, nhge->nh_parent, nlinfo);
}
}
static void remove_nexthop_group(struct nexthop *nh, struct nl_info *nlinfo)
{
struct nh_group *nhg = rcu_dereference_rtnl(nh->nh_grp);
int i, num_nh = nhg->num_nh;
for (i = 0; i < num_nh; ++i) {
struct nh_grp_entry *nhge = &nhg->nh_entries[i];
if (WARN_ON(!nhge->nh))
continue;
list_del(&nhge->nh_list);
nexthop_put(nhge->nh);
nhge->nh = NULL;
nhg->num_nh--;
}
}
static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
{
struct fib6_info *f6i, *tmp;
bool do_flush = false;
struct fib_info *fi;
list_for_each_entry(fi, &nh->fi_list, nh_list) {
fi->fib_flags |= RTNH_F_DEAD;
do_flush = true;
}
if (do_flush)
fib_flush(net);
/* ip6_del_rt removes the entry from this list hence the _safe */
list_for_each_entry_safe(f6i, tmp, &nh->f6i_list, nh_list) {
/* __ip6_del_rt does a release, so do a hold here */
fib6_info_hold(f6i);
ipv6_stub->ip6_del_rt(net, f6i);
}
}
static void __remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
__remove_nexthop_fib(net, nh);
if (nh->is_group) {
remove_nexthop_group(nh, nlinfo);
} else {
struct nh_info *nhi;
nhi = rtnl_dereference(nh->nh_info);
if (nhi->fib_nhc.nhc_dev)
hlist_del(&nhi->dev_hash);
remove_nexthop_from_groups(net, nh, nlinfo);
}
}
static void remove_nexthop(struct net *net, struct nexthop *nh,
struct nl_info *nlinfo)
{
/* remove from the tree */
rb_erase(&nh->rb_node, &net->nexthop.rb_root);
if (nlinfo)
nexthop_notify(RTM_DELNEXTHOP, nh, nlinfo);
__remove_nexthop(net, nh, nlinfo);
nh_base_seq_inc(net);
nexthop_put(nh);
}
static int replace_nexthop(struct net *net, struct nexthop *old,
struct nexthop *new, struct netlink_ext_ack *extack)
{
return -EEXIST;
}
/* called with rtnl_lock held */
static int insert_nexthop(struct net *net, struct nexthop *new_nh,
struct nh_config *cfg, struct netlink_ext_ack *extack)
{
struct rb_node **pp, *parent = NULL, *next;
struct rb_root *root = &net->nexthop.rb_root;
bool replace = !!(cfg->nlflags & NLM_F_REPLACE);
bool create = !!(cfg->nlflags & NLM_F_CREATE);
u32 new_id = new_nh->id;
int rc = -EEXIST;
pp = &root->rb_node;
while (1) {
struct nexthop *nh;
next = rtnl_dereference(*pp);
if (!next)
break;
parent = next;
nh = rb_entry(parent, struct nexthop, rb_node);
if (new_id < nh->id) {
pp = &next->rb_left;
} else if (new_id > nh->id) {
pp = &next->rb_right;
} else if (replace) {
rc = replace_nexthop(net, nh, new_nh, extack);
if (!rc)
new_nh = nh; /* send notification with old nh */
goto out;
} else {
/* id already exists and not a replace */
goto out;
}
}
if (replace && !create) {
NL_SET_ERR_MSG(extack, "Replace specified without create and no entry exists");
rc = -ENOENT;
goto out;
}
rb_link_node_rcu(&new_nh->rb_node, parent, pp);
rb_insert_color(&new_nh->rb_node, root);
rc = 0;
out:
if (!rc) {
nh_base_seq_inc(net);
nexthop_notify(RTM_NEWNEXTHOP, new_nh, &cfg->nlinfo);
}
return rc;
}
/* rtnl */
/* remove all nexthops tied to a device being deleted */
static void nexthop_flush_dev(struct net_device *dev)
{
unsigned int hash = nh_dev_hashfn(dev->ifindex);
struct net *net = dev_net(dev);
struct hlist_head *head = &net->nexthop.devhash[hash];
struct hlist_node *n;
struct nh_info *nhi;
hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
if (nhi->fib_nhc.nhc_dev != dev)
continue;
remove_nexthop(net, nhi->nh_parent, NULL);
}
}
/* rtnl; called when net namespace is deleted */
static void flush_all_nexthops(struct net *net)
{
struct rb_root *root = &net->nexthop.rb_root;
struct rb_node *node;
struct nexthop *nh;
while ((node = rb_first(root))) {
nh = rb_entry(node, struct nexthop, rb_node);
remove_nexthop(net, nh, NULL);
cond_resched();
}
}
static struct nexthop *nexthop_create_group(struct net *net,
struct nh_config *cfg)
{
struct nlattr *grps_attr = cfg->nh_grp;
struct nexthop_grp *entry = nla_data(grps_attr);
struct nh_group *nhg;
struct nexthop *nh;
int i;
nh = nexthop_alloc();
if (!nh)
return ERR_PTR(-ENOMEM);
nh->is_group = 1;
nhg = nexthop_grp_alloc(nla_len(grps_attr) / sizeof(*entry));
if (!nhg) {
kfree(nh);
return ERR_PTR(-ENOMEM);
}
for (i = 0; i < nhg->num_nh; ++i) {
struct nexthop *nhe;
struct nh_info *nhi;
nhe = nexthop_find_by_id(net, entry[i].id);
if (!nexthop_get(nhe))
goto out_no_nh;
nhi = rtnl_dereference(nhe->nh_info);
if (nhi->family == AF_INET)
nhg->has_v4 = true;
nhg->nh_entries[i].nh = nhe;
nhg->nh_entries[i].weight = entry[i].weight + 1;
list_add(&nhg->nh_entries[i].nh_list, &nhe->grp_list);
nhg->nh_entries[i].nh_parent = nh;
}
if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) {
nhg->mpath = 1;
nh_group_rebalance(nhg);
}
rcu_assign_pointer(nh->nh_grp, nhg);
return nh;
out_no_nh:
for (; i >= 0; --i)
nexthop_put(nhg->nh_entries[i].nh);
kfree(nhg);
kfree(nh);
return ERR_PTR(-ENOENT);
}
static int nh_create_ipv4(struct net *net, struct nexthop *nh,
struct nh_info *nhi, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct fib_nh *fib_nh = &nhi->fib_nh;
struct fib_config fib_cfg = {
.fc_oif = cfg->nh_ifindex,
.fc_gw4 = cfg->gw.ipv4,
.fc_gw_family = cfg->gw.ipv4 ? AF_INET : 0,
.fc_flags = cfg->nh_flags,
.fc_encap = cfg->nh_encap,
.fc_encap_type = cfg->nh_encap_type,
};
u32 tb_id = l3mdev_fib_table(cfg->dev);
int err = -EINVAL;
err = fib_nh_init(net, fib_nh, &fib_cfg, 1, extack);
if (err) {
fib_nh_release(net, fib_nh);
goto out;
}
/* sets nh_dev if successful */
err = fib_check_nh(net, fib_nh, tb_id, 0, extack);
if (!err) {
nh->nh_flags = fib_nh->fib_nh_flags;
fib_info_update_nhc_saddr(net, &fib_nh->nh_common,
fib_nh->fib_nh_scope);
} else {
fib_nh_release(net, fib_nh);
}
out:
return err;
}
static int nh_create_ipv6(struct net *net, struct nexthop *nh,
struct nh_info *nhi, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct fib6_nh *fib6_nh = &nhi->fib6_nh;
struct fib6_config fib6_cfg = {
.fc_table = l3mdev_fib_table(cfg->dev),
.fc_ifindex = cfg->nh_ifindex,
.fc_gateway = cfg->gw.ipv6,
.fc_flags = cfg->nh_flags,
.fc_encap = cfg->nh_encap,
.fc_encap_type = cfg->nh_encap_type,
};
int err;
if (!ipv6_addr_any(&cfg->gw.ipv6))
fib6_cfg.fc_flags |= RTF_GATEWAY;
/* sets nh_dev if successful */
err = ipv6_stub->fib6_nh_init(net, fib6_nh, &fib6_cfg, GFP_KERNEL,
extack);
if (err)
ipv6_stub->fib6_nh_release(fib6_nh);
else
nh->nh_flags = fib6_nh->fib_nh_flags;
return err;
}
static struct nexthop *nexthop_create(struct net *net, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nh_info *nhi;
struct nexthop *nh;
int err = 0;
nh = nexthop_alloc();
if (!nh)
return ERR_PTR(-ENOMEM);
nhi = kzalloc(sizeof(*nhi), GFP_KERNEL);
if (!nhi) {
kfree(nh);
return ERR_PTR(-ENOMEM);
}
nh->nh_flags = cfg->nh_flags;
nh->net = net;
nhi->nh_parent = nh;
nhi->family = cfg->nh_family;
nhi->fib_nhc.nhc_scope = RT_SCOPE_LINK;
if (cfg->nh_blackhole) {
nhi->reject_nh = 1;
cfg->nh_ifindex = net->loopback_dev->ifindex;
}
switch (cfg->nh_family) {
case AF_INET:
err = nh_create_ipv4(net, nh, nhi, cfg, extack);
break;
case AF_INET6:
err = nh_create_ipv6(net, nh, nhi, cfg, extack);
break;
}
if (err) {
kfree(nhi);
kfree(nh);
return ERR_PTR(err);
}
/* add the entry to the device based hash */
nexthop_devhash_add(net, nhi);
rcu_assign_pointer(nh->nh_info, nhi);
return nh;
}
/* called with rtnl lock held */
static struct nexthop *nexthop_add(struct net *net, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nexthop *nh;
int err;
if (cfg->nlflags & NLM_F_REPLACE && !cfg->nh_id) {
NL_SET_ERR_MSG(extack, "Replace requires nexthop id");
return ERR_PTR(-EINVAL);
}
if (!cfg->nh_id) {
cfg->nh_id = nh_find_unused_id(net);
if (!cfg->nh_id) {
NL_SET_ERR_MSG(extack, "No unused id");
return ERR_PTR(-EINVAL);
}
}
if (cfg->nh_grp)
nh = nexthop_create_group(net, cfg);
else
nh = nexthop_create(net, cfg, extack);
if (IS_ERR(nh))
return nh;
refcount_set(&nh->refcnt, 1);
nh->id = cfg->nh_id;
nh->protocol = cfg->nh_protocol;
nh->net = net;
err = insert_nexthop(net, nh, cfg, extack);
if (err) {
__remove_nexthop(net, nh, NULL);
nexthop_put(nh);
nh = ERR_PTR(err);
}
return nh;
}
static int rtm_to_nh_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct nh_config *cfg,
struct netlink_ext_ack *extack)
{
struct nhmsg *nhm = nlmsg_data(nlh);
struct nlattr *tb[NHA_MAX + 1];
int err;
err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
extack);
if (err < 0)
return err;
err = -EINVAL;
if (nhm->resvd || nhm->nh_scope) {
NL_SET_ERR_MSG(extack, "Invalid values in ancillary header");
goto out;
}
if (nhm->nh_flags & ~NEXTHOP_VALID_USER_FLAGS) {
NL_SET_ERR_MSG(extack, "Invalid nexthop flags in ancillary header");
goto out;
}
switch (nhm->nh_family) {
case AF_INET:
case AF_INET6:
break;
case AF_UNSPEC:
if (tb[NHA_GROUP])
break;
/* fallthrough */
default:
NL_SET_ERR_MSG(extack, "Invalid address family");
goto out;
}
if (tb[NHA_GROUPS] || tb[NHA_MASTER]) {
NL_SET_ERR_MSG(extack, "Invalid attributes in request");
goto out;
}
memset(cfg, 0, sizeof(*cfg));
cfg->nlflags = nlh->nlmsg_flags;
cfg->nlinfo.portid = NETLINK_CB(skb).portid;
cfg->nlinfo.nlh = nlh;
cfg->nlinfo.nl_net = net;
cfg->nh_family = nhm->nh_family;
cfg->nh_protocol = nhm->nh_protocol;
cfg->nh_flags = nhm->nh_flags;
if (tb[NHA_ID])
cfg->nh_id = nla_get_u32(tb[NHA_ID]);
if (tb[NHA_GROUP]) {
if (nhm->nh_family != AF_UNSPEC) {
NL_SET_ERR_MSG(extack, "Invalid family for group");
goto out;
}
cfg->nh_grp = tb[NHA_GROUP];
cfg->nh_grp_type = NEXTHOP_GRP_TYPE_MPATH;
if (tb[NHA_GROUP_TYPE])
cfg->nh_grp_type = nla_get_u16(tb[NHA_GROUP_TYPE]);
if (cfg->nh_grp_type > NEXTHOP_GRP_TYPE_MAX) {
NL_SET_ERR_MSG(extack, "Invalid group type");
goto out;
}
err = nh_check_attr_group(net, tb, extack);
/* no other attributes should be set */
goto out;
}
if (tb[NHA_BLACKHOLE]) {
if (tb[NHA_GATEWAY] || tb[NHA_OIF] ||
tb[NHA_ENCAP] || tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "Blackhole attribute can not be used with gateway or oif");
goto out;
}
cfg->nh_blackhole = 1;
err = 0;
goto out;
}
if (!tb[NHA_OIF]) {
NL_SET_ERR_MSG(extack, "Device attribute required for non-blackhole nexthops");
goto out;
}
cfg->nh_ifindex = nla_get_u32(tb[NHA_OIF]);
if (cfg->nh_ifindex)
cfg->dev = __dev_get_by_index(net, cfg->nh_ifindex);
if (!cfg->dev) {
NL_SET_ERR_MSG(extack, "Invalid device index");
goto out;
} else if (!(cfg->dev->flags & IFF_UP)) {
NL_SET_ERR_MSG(extack, "Nexthop device is not up");
err = -ENETDOWN;
goto out;
} else if (!netif_carrier_ok(cfg->dev)) {
NL_SET_ERR_MSG(extack, "Carrier for nexthop device is down");
err = -ENETDOWN;
goto out;
}
err = -EINVAL;
if (tb[NHA_GATEWAY]) {
struct nlattr *gwa = tb[NHA_GATEWAY];
switch (cfg->nh_family) {
case AF_INET:
if (nla_len(gwa) != sizeof(u32)) {
NL_SET_ERR_MSG(extack, "Invalid gateway");
goto out;
}
cfg->gw.ipv4 = nla_get_be32(gwa);
break;
case AF_INET6:
if (nla_len(gwa) != sizeof(struct in6_addr)) {
NL_SET_ERR_MSG(extack, "Invalid gateway");
goto out;
}
cfg->gw.ipv6 = nla_get_in6_addr(gwa);
break;
default:
NL_SET_ERR_MSG(extack,
"Unknown address family for gateway");
goto out;
}
} else {
/* device only nexthop (no gateway) */
if (cfg->nh_flags & RTNH_F_ONLINK) {
NL_SET_ERR_MSG(extack,
"ONLINK flag can not be set for nexthop without a gateway");
goto out;
}
}
if (tb[NHA_ENCAP]) {
cfg->nh_encap = tb[NHA_ENCAP];
if (!tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "LWT encapsulation type is missing");
goto out;
}
cfg->nh_encap_type = nla_get_u16(tb[NHA_ENCAP_TYPE]);
err = lwtunnel_valid_encap_type(cfg->nh_encap_type, extack);
if (err < 0)
goto out;
} else if (tb[NHA_ENCAP_TYPE]) {
NL_SET_ERR_MSG(extack, "LWT encapsulation attribute is missing");
goto out;
}
err = 0;
out:
return err;
}
/* rtnl */
static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nh_config cfg;
struct nexthop *nh;
int err;
err = rtm_to_nh_config(net, skb, nlh, &cfg, extack);
if (!err) {
nh = nexthop_add(net, &cfg, extack);
if (IS_ERR(nh))
err = PTR_ERR(nh);
}
return err;
}
static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id,
struct netlink_ext_ack *extack)
{
struct nhmsg *nhm = nlmsg_data(nlh);
struct nlattr *tb[NHA_MAX + 1];
int err, i;
err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
extack);
if (err < 0)
return err;
err = -EINVAL;
for (i = 0; i < __NHA_MAX; ++i) {
if (!tb[i])
continue;
switch (i) {
case NHA_ID:
break;
default:
NL_SET_ERR_MSG_ATTR(extack, tb[i],
"Unexpected attribute in request");
goto out;
}
}
if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
NL_SET_ERR_MSG(extack, "Invalid values in header");
goto out;
}
if (!tb[NHA_ID]) {
NL_SET_ERR_MSG(extack, "Nexthop id is missing");
goto out;
}
*id = nla_get_u32(tb[NHA_ID]);
if (!(*id))
NL_SET_ERR_MSG(extack, "Invalid nexthop id");
else
err = 0;
out:
return err;
}
/* rtnl */
static int rtm_del_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct nl_info nlinfo = {
.nlh = nlh,
.nl_net = net,
.portid = NETLINK_CB(skb).portid,
};
struct nexthop *nh;
int err;
u32 id;
err = nh_valid_get_del_req(nlh, &id, extack);
if (err)
return err;
nh = nexthop_find_by_id(net, id);
if (!nh)
return -ENOENT;
remove_nexthop(net, nh, &nlinfo);
return 0;
}
/* rtnl */
static int rtm_get_nexthop(struct sk_buff *in_skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(in_skb->sk);
struct sk_buff *skb = NULL;
struct nexthop *nh;
int err;
u32 id;
err = nh_valid_get_del_req(nlh, &id, extack);
if (err)
return err;
err = -ENOBUFS;
skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
if (!skb)
goto out;
err = -ENOENT;
nh = nexthop_find_by_id(net, id);
if (!nh)
goto errout_free;
err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP, NETLINK_CB(in_skb).portid,
nlh->nlmsg_seq, 0);
if (err < 0) {
WARN_ON(err == -EMSGSIZE);
goto errout_free;
}
err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid);
out:
return err;
errout_free:
kfree_skb(skb);
goto out;
}
static bool nh_dump_filtered(struct nexthop *nh, int dev_idx, int master_idx,
bool group_filter, u8 family)
{
const struct net_device *dev;
const struct nh_info *nhi;
if (group_filter && !nh->is_group)
return true;
if (!dev_idx && !master_idx && !family)
return false;
if (nh->is_group)
return true;
nhi = rtnl_dereference(nh->nh_info);
if (family && nhi->family != family)
return true;
dev = nhi->fib_nhc.nhc_dev;
if (dev_idx && (!dev || dev->ifindex != dev_idx))
return true;
if (master_idx) {
struct net_device *master;
if (!dev)
return true;
master = netdev_master_upper_dev_get((struct net_device *)dev);
if (!master || master->ifindex != master_idx)
return true;
}
return false;
}
static int nh_valid_dump_req(const struct nlmsghdr *nlh, int *dev_idx,
int *master_idx, bool *group_filter,
struct netlink_callback *cb)
{
struct netlink_ext_ack *extack = cb->extack;
struct nlattr *tb[NHA_MAX + 1];
struct nhmsg *nhm;
int err, i;
u32 idx;
err = nlmsg_parse(nlh, sizeof(*nhm), tb, NHA_MAX, rtm_nh_policy,
NULL);
if (err < 0)
return err;
for (i = 0; i <= NHA_MAX; ++i) {
if (!tb[i])
continue;
switch (i) {
case NHA_OIF:
idx = nla_get_u32(tb[i]);
if (idx > INT_MAX) {
NL_SET_ERR_MSG(extack, "Invalid device index");
return -EINVAL;
}
*dev_idx = idx;
break;
case NHA_MASTER:
idx = nla_get_u32(tb[i]);
if (idx > INT_MAX) {
NL_SET_ERR_MSG(extack, "Invalid master device index");
return -EINVAL;
}
*master_idx = idx;
break;
case NHA_GROUPS:
*group_filter = true;
break;
default:
NL_SET_ERR_MSG(extack, "Unsupported attribute in dump request");
return -EINVAL;
}
}
nhm = nlmsg_data(nlh);
if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
NL_SET_ERR_MSG(extack, "Invalid values in header for nexthop dump request");
return -EINVAL;
}
return 0;
}
/* rtnl */
static int rtm_dump_nexthop(struct sk_buff *skb, struct netlink_callback *cb)
{
struct nhmsg *nhm = nlmsg_data(cb->nlh);
int dev_filter_idx = 0, master_idx = 0;
struct net *net = sock_net(skb->sk);
struct rb_root *root = &net->nexthop.rb_root;
bool group_filter = false;
struct rb_node *node;
int idx = 0, s_idx;
int err;
err = nh_valid_dump_req(cb->nlh, &dev_filter_idx, &master_idx,
&group_filter, cb);
if (err < 0)
return err;
s_idx = cb->args[0];
for (node = rb_first(root); node; node = rb_next(node)) {
struct nexthop *nh;
if (idx < s_idx)
goto cont;
nh = rb_entry(node, struct nexthop, rb_node);
if (nh_dump_filtered(nh, dev_filter_idx, master_idx,
group_filter, nhm->nh_family))
goto cont;
err = nh_fill_node(skb, nh, RTM_NEWNEXTHOP,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI);
if (err < 0) {
if (likely(skb->len))
goto out;
goto out_err;
}
cont:
idx++;
}
out:
err = skb->len;
out_err:
cb->args[0] = idx;
cb->seq = net->nexthop.seq;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
return err;
}
static void nexthop_sync_mtu(struct net_device *dev, u32 orig_mtu)
{
unsigned int hash = nh_dev_hashfn(dev->ifindex);
struct net *net = dev_net(dev);
struct hlist_head *head = &net->nexthop.devhash[hash];
struct hlist_node *n;
struct nh_info *nhi;
hlist_for_each_entry_safe(nhi, n, head, dev_hash) {
if (nhi->fib_nhc.nhc_dev == dev) {
if (nhi->family == AF_INET)
fib_nhc_update_mtu(&nhi->fib_nhc, dev->mtu,
orig_mtu);
}
}
}
/* rtnl */
static int nh_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct netdev_notifier_info_ext *info_ext;
switch (event) {
case NETDEV_DOWN:
case NETDEV_UNREGISTER:
nexthop_flush_dev(dev);
break;
case NETDEV_CHANGE:
if (!(dev_get_flags(dev) & (IFF_RUNNING | IFF_LOWER_UP)))
nexthop_flush_dev(dev);
break;
case NETDEV_CHANGEMTU:
info_ext = ptr;
nexthop_sync_mtu(dev, info_ext->ext.mtu);
rt_cache_flush(dev_net(dev));
break;
}
return NOTIFY_DONE;
}
static struct notifier_block nh_netdev_notifier = {
.notifier_call = nh_netdev_event,
};
static void __net_exit nexthop_net_exit(struct net *net)
{
rtnl_lock();
flush_all_nexthops(net);
rtnl_unlock();
kfree(net->nexthop.devhash);
}
static int __net_init nexthop_net_init(struct net *net)
{
size_t sz = sizeof(struct hlist_head) * NH_DEV_HASHSIZE;
net->nexthop.rb_root = RB_ROOT;
net->nexthop.devhash = kzalloc(sz, GFP_KERNEL);
if (!net->nexthop.devhash)
return -ENOMEM;
return 0;
}
static struct pernet_operations nexthop_net_ops = {
.init = nexthop_net_init,
.exit = nexthop_net_exit,
};
static int __init nexthop_init(void)
{
register_pernet_subsys(&nexthop_net_ops);
register_netdevice_notifier(&nh_netdev_notifier);
rtnl_register(PF_UNSPEC, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_DELNEXTHOP, rtm_del_nexthop, NULL, 0);
rtnl_register(PF_UNSPEC, RTM_GETNEXTHOP, rtm_get_nexthop,
rtm_dump_nexthop, 0);
rtnl_register(PF_INET, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_INET, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
rtnl_register(PF_INET6, RTM_NEWNEXTHOP, rtm_new_nexthop, NULL, 0);
rtnl_register(PF_INET6, RTM_GETNEXTHOP, NULL, rtm_dump_nexthop, 0);
return 0;
}
subsys_initcall(nexthop_init);