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linux/net/ipv4/fib_frontend.c
Paolo Abeni 6e617de84e net: avoid a full fib lookup when rp_filter is disabled. 
Since commit 1dced6a854 ("ipv4: Restore accept_local behaviour
in fib_validate_source()") a full fib lookup is needed even if
the rp_filter is disabled, if accept_local is false - which is
the default.

What we really need in the above scenario is just checking
that the source IP address is not local, and in most case we
can do that is a cheaper way looking up the ifaddr hash table.

This commit adds a helper for such lookup, and uses it to
validate the src address when rp_filter is disabled and no
'local' routes are created by the user space in the relevant
namespace.

A new ipv4 netns flag is added to account for such routes.
We need that to preserve the same behavior we had before this
patch.

It also drops the checks to bail early from __fib_validate_source,
added by the commit 1dced6a854 ("ipv4: Restore accept_local
behaviour in fib_validate_source()") they do not give any
measurable performance improvement: if we do the lookup with are
on a slower path.

This improves UDP performances for unconnected sockets
when rp_filter is disabled by 5% and also gives small but
measurable performance improvement for TCP flood scenarios.

v1 -> v2:
 - use the ifaddr lookup helper in __ip_dev_find(), as suggested
   by Eric
 - fall-back to full lookup if custom local routes are present

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-09-21 15:15:22 -07:00

1367 lines
32 KiB
C
Raw Blame History

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* IPv4 Forwarding Information Base: FIB frontend.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_addr.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/cache.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/ip_fib.h>
#include <net/rtnetlink.h>
#include <net/xfrm.h>
#include <net/l3mdev.h>
#include <net/lwtunnel.h>
#include <trace/events/fib.h>
#ifndef CONFIG_IP_MULTIPLE_TABLES
static int __net_init fib4_rules_init(struct net *net)
{
struct fib_table *local_table, *main_table;
main_table = fib_trie_table(RT_TABLE_MAIN, NULL);
if (!main_table)
return -ENOMEM;
local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
if (!local_table)
goto fail;
hlist_add_head_rcu(&local_table->tb_hlist,
&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
hlist_add_head_rcu(&main_table->tb_hlist,
&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
return 0;
fail:
fib_free_table(main_table);
return -ENOMEM;
}
#else
struct fib_table *fib_new_table(struct net *net, u32 id)
{
struct fib_table *tb, *alias = NULL;
unsigned int h;
if (id == 0)
id = RT_TABLE_MAIN;
tb = fib_get_table(net, id);
if (tb)
return tb;
if (id == RT_TABLE_LOCAL && !net->ipv4.fib_has_custom_rules)
alias = fib_new_table(net, RT_TABLE_MAIN);
tb = fib_trie_table(id, alias);
if (!tb)
return NULL;
switch (id) {
case RT_TABLE_MAIN:
rcu_assign_pointer(net->ipv4.fib_main, tb);
break;
case RT_TABLE_DEFAULT:
rcu_assign_pointer(net->ipv4.fib_default, tb);
break;
default:
break;
}
h = id & (FIB_TABLE_HASHSZ - 1);
hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
return tb;
}
EXPORT_SYMBOL_GPL(fib_new_table);
/* caller must hold either rtnl or rcu read lock */
struct fib_table *fib_get_table(struct net *net, u32 id)
{
struct fib_table *tb;
struct hlist_head *head;
unsigned int h;
if (id == 0)
id = RT_TABLE_MAIN;
h = id & (FIB_TABLE_HASHSZ - 1);
head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
if (tb->tb_id == id)
return tb;
}
return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */
static void fib_replace_table(struct net *net, struct fib_table *old,
struct fib_table *new)
{
#ifdef CONFIG_IP_MULTIPLE_TABLES
switch (new->tb_id) {
case RT_TABLE_MAIN:
rcu_assign_pointer(net->ipv4.fib_main, new);
break;
case RT_TABLE_DEFAULT:
rcu_assign_pointer(net->ipv4.fib_default, new);
break;
default:
break;
}
#endif
/* replace the old table in the hlist */
hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
}
int fib_unmerge(struct net *net)
{
struct fib_table *old, *new, *main_table;
/* attempt to fetch local table if it has been allocated */
old = fib_get_table(net, RT_TABLE_LOCAL);
if (!old)
return 0;
new = fib_trie_unmerge(old);
if (!new)
return -ENOMEM;
/* table is already unmerged */
if (new == old)
return 0;
/* replace merged table with clean table */
fib_replace_table(net, old, new);
fib_free_table(old);
/* attempt to fetch main table if it has been allocated */
main_table = fib_get_table(net, RT_TABLE_MAIN);
if (!main_table)
return 0;
/* flush local entries from main table */
fib_table_flush_external(main_table);
return 0;
}
static void fib_flush(struct net *net)
{
int flushed = 0;
unsigned int h;
for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
struct hlist_head *head = &net->ipv4.fib_table_hash[h];
struct hlist_node *tmp;
struct fib_table *tb;
hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
flushed += fib_table_flush(net, tb);
}
if (flushed)
rt_cache_flush(net);
}
/*
* Find address type as if only "dev" was present in the system. If
* on_dev is NULL then all interfaces are taken into consideration.
*/
static inline unsigned int __inet_dev_addr_type(struct net *net,
const struct net_device *dev,
__be32 addr, u32 tb_id)
{
struct flowi4 fl4 = { .daddr = addr };
struct fib_result res;
unsigned int ret = RTN_BROADCAST;
struct fib_table *table;
if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
return RTN_BROADCAST;
if (ipv4_is_multicast(addr))
return RTN_MULTICAST;
rcu_read_lock();
table = fib_get_table(net, tb_id);
if (table) {
ret = RTN_UNICAST;
if (!fib_table_lookup(table, &fl4, &res, FIB_LOOKUP_NOREF)) {
if (!dev || dev == res.fi->fib_dev)
ret = res.type;
}
}
rcu_read_unlock();
return ret;
}
unsigned int inet_addr_type_table(struct net *net, __be32 addr, u32 tb_id)
{
return __inet_dev_addr_type(net, NULL, addr, tb_id);
}
EXPORT_SYMBOL(inet_addr_type_table);
unsigned int inet_addr_type(struct net *net, __be32 addr)
{
return __inet_dev_addr_type(net, NULL, addr, RT_TABLE_LOCAL);
}
EXPORT_SYMBOL(inet_addr_type);
unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
__be32 addr)
{
u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
return __inet_dev_addr_type(net, dev, addr, rt_table);
}
EXPORT_SYMBOL(inet_dev_addr_type);
/* inet_addr_type with dev == NULL but using the table from a dev
* if one is associated
*/
unsigned int inet_addr_type_dev_table(struct net *net,
const struct net_device *dev,
__be32 addr)
{
u32 rt_table = l3mdev_fib_table(dev) ? : RT_TABLE_LOCAL;
return __inet_dev_addr_type(net, NULL, addr, rt_table);
}
EXPORT_SYMBOL(inet_addr_type_dev_table);
__be32 fib_compute_spec_dst(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
struct in_device *in_dev;
struct fib_result res;
struct rtable *rt;
struct net *net;
int scope;
rt = skb_rtable(skb);
if ((rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL)) ==
RTCF_LOCAL)
return ip_hdr(skb)->daddr;
in_dev = __in_dev_get_rcu(dev);
BUG_ON(!in_dev);
net = dev_net(dev);
scope = RT_SCOPE_UNIVERSE;
if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
struct flowi4 fl4 = {
.flowi4_iif = LOOPBACK_IFINDEX,
.daddr = ip_hdr(skb)->saddr,
.flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
.flowi4_scope = scope,
.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0,
};
if (!fib_lookup(net, &fl4, &res, 0))
return FIB_RES_PREFSRC(net, res);
} else {
scope = RT_SCOPE_LINK;
}
return inet_select_addr(dev, ip_hdr(skb)->saddr, scope);
}
/* Given (packet source, input interface) and optional (dst, oif, tos):
* - (main) check, that source is valid i.e. not broadcast or our local
* address.
* - figure out what "logical" interface this packet arrived
* and calculate "specific destination" address.
* - check, that packet arrived from expected physical interface.
* called with rcu_read_lock()
*/
static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
u8 tos, int oif, struct net_device *dev,
int rpf, struct in_device *idev, u32 *itag)
{
int ret, no_addr;
struct fib_result res;
struct flowi4 fl4;
struct net *net = dev_net(dev);
bool dev_match;
fl4.flowi4_oif = 0;
fl4.flowi4_iif = l3mdev_master_ifindex_rcu(dev);
if (!fl4.flowi4_iif)
fl4.flowi4_iif = oif ? : LOOPBACK_IFINDEX;
fl4.daddr = src;
fl4.saddr = dst;
fl4.flowi4_tos = tos;
fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
fl4.flowi4_tun_key.tun_id = 0;
fl4.flowi4_flags = 0;
fl4.flowi4_uid = sock_net_uid(net, NULL);
no_addr = idev->ifa_list == NULL;
fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0;
trace_fib_validate_source(dev, &fl4);
if (fib_lookup(net, &fl4, &res, 0))
goto last_resort;
if (res.type != RTN_UNICAST &&
(res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
goto e_inval;
fib_combine_itag(itag, &res);
dev_match = false;
#ifdef CONFIG_IP_ROUTE_MULTIPATH
for (ret = 0; ret < res.fi->fib_nhs; ret++) {
struct fib_nh *nh = &res.fi->fib_nh[ret];
if (nh->nh_dev == dev) {
dev_match = true;
break;
} else if (l3mdev_master_ifindex_rcu(nh->nh_dev) == dev->ifindex) {
dev_match = true;
break;
}
}
#else
if (FIB_RES_DEV(res) == dev)
dev_match = true;
#endif
if (dev_match) {
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
return ret;
}
if (no_addr)
goto last_resort;
if (rpf == 1)
goto e_rpf;
fl4.flowi4_oif = dev->ifindex;
ret = 0;
if (fib_lookup(net, &fl4, &res, FIB_LOOKUP_IGNORE_LINKSTATE) == 0) {
if (res.type == RTN_UNICAST)
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
}
return ret;
last_resort:
if (rpf)
goto e_rpf;
*itag = 0;
return 0;
e_inval:
return -EINVAL;
e_rpf:
return -EXDEV;
}
/* Ignore rp_filter for packets protected by IPsec. */
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
u8 tos, int oif, struct net_device *dev,
struct in_device *idev, u32 *itag)
{
int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
struct net *net = dev_net(dev);
if (!r && !fib_num_tclassid_users(net) &&
(dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
if (IN_DEV_ACCEPT_LOCAL(idev))
goto ok;
/* if no local routes are added from user space we can check
* for local addresses looking-up the ifaddr table
*/
if (net->ipv4.fib_has_custom_local_routes)
goto full_check;
if (inet_lookup_ifaddr_rcu(net, src))
return -EINVAL;
ok:
*itag = 0;
return 0;
}
full_check:
return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
}
static inline __be32 sk_extract_addr(struct sockaddr *addr)
{
return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
}
static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
{
struct nlattr *nla;
nla = (struct nlattr *) ((char *) mx + len);
nla->nla_type = type;
nla->nla_len = nla_attr_size(4);
*(u32 *) nla_data(nla) = value;
return len + nla_total_size(4);
}
static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
struct fib_config *cfg)
{
__be32 addr;
int plen;
memset(cfg, 0, sizeof(*cfg));
cfg->fc_nlinfo.nl_net = net;
if (rt->rt_dst.sa_family != AF_INET)
return -EAFNOSUPPORT;
/*
* Check mask for validity:
* a) it must be contiguous.
* b) destination must have all host bits clear.
* c) if application forgot to set correct family (AF_INET),
* reject request unless it is absolutely clear i.e.
* both family and mask are zero.
*/
plen = 32;
addr = sk_extract_addr(&rt->rt_dst);
if (!(rt->rt_flags & RTF_HOST)) {
__be32 mask = sk_extract_addr(&rt->rt_genmask);
if (rt->rt_genmask.sa_family != AF_INET) {
if (mask || rt->rt_genmask.sa_family)
return -EAFNOSUPPORT;
}
if (bad_mask(mask, addr))
return -EINVAL;
plen = inet_mask_len(mask);
}
cfg->fc_dst_len = plen;
cfg->fc_dst = addr;
if (cmd != SIOCDELRT) {
cfg->fc_nlflags = NLM_F_CREATE;
cfg->fc_protocol = RTPROT_BOOT;
}
if (rt->rt_metric)
cfg->fc_priority = rt->rt_metric - 1;
if (rt->rt_flags & RTF_REJECT) {
cfg->fc_scope = RT_SCOPE_HOST;
cfg->fc_type = RTN_UNREACHABLE;
return 0;
}
cfg->fc_scope = RT_SCOPE_NOWHERE;
cfg->fc_type = RTN_UNICAST;
if (rt->rt_dev) {
char *colon;
struct net_device *dev;
char devname[IFNAMSIZ];
if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
return -EFAULT;
devname[IFNAMSIZ-1] = 0;
colon = strchr(devname, ':');
if (colon)
*colon = 0;
dev = __dev_get_by_name(net, devname);
if (!dev)
return -ENODEV;
cfg->fc_oif = dev->ifindex;
cfg->fc_table = l3mdev_fib_table(dev);
if (colon) {
struct in_ifaddr *ifa;
struct in_device *in_dev = __in_dev_get_rtnl(dev);
if (!in_dev)
return -ENODEV;
*colon = ':';
for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
if (strcmp(ifa->ifa_label, devname) == 0)
break;
if (!ifa)
return -ENODEV;
cfg->fc_prefsrc = ifa->ifa_local;
}
}
addr = sk_extract_addr(&rt->rt_gateway);
if (rt->rt_gateway.sa_family == AF_INET && addr) {
unsigned int addr_type;
cfg->fc_gw = addr;
addr_type = inet_addr_type_table(net, addr, cfg->fc_table);
if (rt->rt_flags & RTF_GATEWAY &&
addr_type == RTN_UNICAST)
cfg->fc_scope = RT_SCOPE_UNIVERSE;
}
if (cmd == SIOCDELRT)
return 0;
if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
return -EINVAL;
if (cfg->fc_scope == RT_SCOPE_NOWHERE)
cfg->fc_scope = RT_SCOPE_LINK;
if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
struct nlattr *mx;
int len = 0;
mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
if (!mx)
return -ENOMEM;
if (rt->rt_flags & RTF_MTU)
len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);
if (rt->rt_flags & RTF_WINDOW)
len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);
if (rt->rt_flags & RTF_IRTT)
len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);
cfg->fc_mx = mx;
cfg->fc_mx_len = len;
}
return 0;
}
/*
* Handle IP routing ioctl calls.
* These are used to manipulate the routing tables
*/
int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
{
struct fib_config cfg;
struct rtentry rt;
int err;
switch (cmd) {
case SIOCADDRT: /* Add a route */
case SIOCDELRT: /* Delete a route */
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
return -EPERM;
if (copy_from_user(&rt, arg, sizeof(rt)))
return -EFAULT;
rtnl_lock();
err = rtentry_to_fib_config(net, cmd, &rt, &cfg);
if (err == 0) {
struct fib_table *tb;
if (cmd == SIOCDELRT) {
tb = fib_get_table(net, cfg.fc_table);
if (tb)
err = fib_table_delete(net, tb, &cfg,
NULL);
else
err = -ESRCH;
} else {
tb = fib_new_table(net, cfg.fc_table);
if (tb)
err = fib_table_insert(net, tb,
&cfg, NULL);
else
err = -ENOBUFS;
}
/* allocated by rtentry_to_fib_config() */
kfree(cfg.fc_mx);
}
rtnl_unlock();
return err;
}
return -EINVAL;
}
const struct nla_policy rtm_ipv4_policy[RTA_MAX + 1] = {
[RTA_DST] = { .type = NLA_U32 },
[RTA_SRC] = { .type = NLA_U32 },
[RTA_IIF] = { .type = NLA_U32 },
[RTA_OIF] = { .type = NLA_U32 },
[RTA_GATEWAY] = { .type = NLA_U32 },
[RTA_PRIORITY] = { .type = NLA_U32 },
[RTA_PREFSRC] = { .type = NLA_U32 },
[RTA_METRICS] = { .type = NLA_NESTED },
[RTA_MULTIPATH] = { .len = sizeof(struct rtnexthop) },
[RTA_FLOW] = { .type = NLA_U32 },
[RTA_ENCAP_TYPE] = { .type = NLA_U16 },
[RTA_ENCAP] = { .type = NLA_NESTED },
[RTA_UID] = { .type = NLA_U32 },
[RTA_MARK] = { .type = NLA_U32 },
};
static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_config *cfg,
struct netlink_ext_ack *extack)
{
struct nlattr *attr;
int err, remaining;
struct rtmsg *rtm;
err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy,
extack);
if (err < 0)
goto errout;
memset(cfg, 0, sizeof(*cfg));
rtm = nlmsg_data(nlh);
cfg->fc_dst_len = rtm->rtm_dst_len;
cfg->fc_tos = rtm->rtm_tos;
cfg->fc_table = rtm->rtm_table;
cfg->fc_protocol = rtm->rtm_protocol;
cfg->fc_scope = rtm->rtm_scope;
cfg->fc_type = rtm->rtm_type;
cfg->fc_flags = rtm->rtm_flags;
cfg->fc_nlflags = nlh->nlmsg_flags;
cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
cfg->fc_nlinfo.nlh = nlh;
cfg->fc_nlinfo.nl_net = net;
if (cfg->fc_type > RTN_MAX) {
NL_SET_ERR_MSG(extack, "Invalid route type");
err = -EINVAL;
goto errout;
}
nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
switch (nla_type(attr)) {
case RTA_DST:
cfg->fc_dst = nla_get_be32(attr);
break;
case RTA_OIF:
cfg->fc_oif = nla_get_u32(attr);
break;
case RTA_GATEWAY:
cfg->fc_gw = nla_get_be32(attr);
break;
case RTA_PRIORITY:
cfg->fc_priority = nla_get_u32(attr);
break;
case RTA_PREFSRC:
cfg->fc_prefsrc = nla_get_be32(attr);
break;
case RTA_METRICS:
cfg->fc_mx = nla_data(attr);
cfg->fc_mx_len = nla_len(attr);
break;
case RTA_MULTIPATH:
err = lwtunnel_valid_encap_type_attr(nla_data(attr),
nla_len(attr),
extack);
if (err < 0)
goto errout;
cfg->fc_mp = nla_data(attr);
cfg->fc_mp_len = nla_len(attr);
break;
case RTA_FLOW:
cfg->fc_flow = nla_get_u32(attr);
break;
case RTA_TABLE:
cfg->fc_table = nla_get_u32(attr);
break;
case RTA_ENCAP:
cfg->fc_encap = attr;
break;
case RTA_ENCAP_TYPE:
cfg->fc_encap_type = nla_get_u16(attr);
err = lwtunnel_valid_encap_type(cfg->fc_encap_type,
extack);
if (err < 0)
goto errout;
break;
}
}
return 0;
errout:
return err;
}
static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct fib_config cfg;
struct fib_table *tb;
int err;
err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
if (err < 0)
goto errout;
tb = fib_get_table(net, cfg.fc_table);
if (!tb) {
NL_SET_ERR_MSG(extack, "FIB table does not exist");
err = -ESRCH;
goto errout;
}
err = fib_table_delete(net, tb, &cfg, extack);
errout:
return err;
}
static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
struct fib_config cfg;
struct fib_table *tb;
int err;
err = rtm_to_fib_config(net, skb, nlh, &cfg, extack);
if (err < 0)
goto errout;
tb = fib_new_table(net, cfg.fc_table);
if (!tb) {
err = -ENOBUFS;
goto errout;
}
err = fib_table_insert(net, tb, &cfg, extack);
if (!err && cfg.fc_type == RTN_LOCAL)
net->ipv4.fib_has_custom_local_routes = true;
errout:
return err;
}
static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net *net = sock_net(skb->sk);
unsigned int h, s_h;
unsigned int e = 0, s_e;
struct fib_table *tb;
struct hlist_head *head;
int dumped = 0, err;
if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
return skb->len;
s_h = cb->args[0];
s_e = cb->args[1];
rcu_read_lock();
for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
e = 0;
head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, head, tb_hlist) {
if (e < s_e)
goto next;
if (dumped)
memset(&cb->args[2], 0, sizeof(cb->args) -
2 * sizeof(cb->args[0]));
err = fib_table_dump(tb, skb, cb);
if (err < 0) {
if (likely(skb->len))
goto out;
goto out_err;
}
dumped = 1;
next:
e++;
}
}
out:
err = skb->len;
out_err:
rcu_read_unlock();
cb->args[1] = e;
cb->args[0] = h;
return err;
}
/* Prepare and feed intra-kernel routing request.
* Really, it should be netlink message, but :-( netlink
* can be not configured, so that we feed it directly
* to fib engine. It is legal, because all events occur
* only when netlink is already locked.
*/
static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
{
struct net *net = dev_net(ifa->ifa_dev->dev);
u32 tb_id = l3mdev_fib_table(ifa->ifa_dev->dev);
struct fib_table *tb;
struct fib_config cfg = {
.fc_protocol = RTPROT_KERNEL,
.fc_type = type,
.fc_dst = dst,
.fc_dst_len = dst_len,
.fc_prefsrc = ifa->ifa_local,
.fc_oif = ifa->ifa_dev->dev->ifindex,
.fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
.fc_nlinfo = {
.nl_net = net,
},
};
if (!tb_id)
tb_id = (type == RTN_UNICAST) ? RT_TABLE_MAIN : RT_TABLE_LOCAL;
tb = fib_new_table(net, tb_id);
if (!tb)
return;
cfg.fc_table = tb->tb_id;
if (type != RTN_LOCAL)
cfg.fc_scope = RT_SCOPE_LINK;
else
cfg.fc_scope = RT_SCOPE_HOST;
if (cmd == RTM_NEWROUTE)
fib_table_insert(net, tb, &cfg, NULL);
else
fib_table_delete(net, tb, &cfg, NULL);
}
void fib_add_ifaddr(struct in_ifaddr *ifa)
{
struct in_device *in_dev = ifa->ifa_dev;
struct net_device *dev = in_dev->dev;
struct in_ifaddr *prim = ifa;
__be32 mask = ifa->ifa_mask;
__be32 addr = ifa->ifa_local;
__be32 prefix = ifa->ifa_address & mask;
if (ifa->ifa_flags & IFA_F_SECONDARY) {
prim = inet_ifa_byprefix(in_dev, prefix, mask);
if (!prim) {
pr_warn("%s: bug: prim == NULL\n", __func__);
return;
}
}
fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);
if (!(dev->flags & IFF_UP))
return;
/* Add broadcast address, if it is explicitly assigned. */
if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
if (!ipv4_is_zeronet(prefix) && !(ifa->ifa_flags & IFA_F_SECONDARY) &&
(prefix != addr || ifa->ifa_prefixlen < 32)) {
if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
fib_magic(RTM_NEWROUTE,
dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
prefix, ifa->ifa_prefixlen, prim);
/* Add network specific broadcasts, when it takes a sense */
if (ifa->ifa_prefixlen < 31) {
fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix | ~mask,
32, prim);
}
}
}
/* Delete primary or secondary address.
* Optionally, on secondary address promotion consider the addresses
* from subnet iprim as deleted, even if they are in device list.
* In this case the secondary ifa can be in device list.
*/
void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
{
struct in_device *in_dev = ifa->ifa_dev;
struct net_device *dev = in_dev->dev;
struct in_ifaddr *ifa1;
struct in_ifaddr *prim = ifa, *prim1 = NULL;
__be32 brd = ifa->ifa_address | ~ifa->ifa_mask;
__be32 any = ifa->ifa_address & ifa->ifa_mask;
#define LOCAL_OK 1
#define BRD_OK 2
#define BRD0_OK 4
#define BRD1_OK 8
unsigned int ok = 0;
int subnet = 0; /* Primary network */
int gone = 1; /* Address is missing */
int same_prefsrc = 0; /* Another primary with same IP */
if (ifa->ifa_flags & IFA_F_SECONDARY) {
prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
if (!prim) {
/* if the device has been deleted, we don't perform
* address promotion
*/
if (!in_dev->dead)
pr_warn("%s: bug: prim == NULL\n", __func__);
return;
}
if (iprim && iprim != prim) {
pr_warn("%s: bug: iprim != prim\n", __func__);
return;
}
} else if (!ipv4_is_zeronet(any) &&
(any != ifa->ifa_local || ifa->ifa_prefixlen < 32)) {
if (!(ifa->ifa_flags & IFA_F_NOPREFIXROUTE))
fib_magic(RTM_DELROUTE,
dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
any, ifa->ifa_prefixlen, prim);
subnet = 1;
}
if (in_dev->dead)
goto no_promotions;
/* Deletion is more complicated than add.
* We should take care of not to delete too much :-)
*
* Scan address list to be sure that addresses are really gone.
*/
for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
if (ifa1 == ifa) {
/* promotion, keep the IP */
gone = 0;
continue;
}
/* Ignore IFAs from our subnet */
if (iprim && ifa1->ifa_mask == iprim->ifa_mask &&
inet_ifa_match(ifa1->ifa_address, iprim))
continue;
/* Ignore ifa1 if it uses different primary IP (prefsrc) */
if (ifa1->ifa_flags & IFA_F_SECONDARY) {
/* Another address from our subnet? */
if (ifa1->ifa_mask == prim->ifa_mask &&
inet_ifa_match(ifa1->ifa_address, prim))
prim1 = prim;
else {
/* We reached the secondaries, so
* same_prefsrc should be determined.
*/
if (!same_prefsrc)
continue;
/* Search new prim1 if ifa1 is not
* using the current prim1
*/
if (!prim1 ||
ifa1->ifa_mask != prim1->ifa_mask ||
!inet_ifa_match(ifa1->ifa_address, prim1))
prim1 = inet_ifa_byprefix(in_dev,
ifa1->ifa_address,
ifa1->ifa_mask);
if (!prim1)
continue;
if (prim1->ifa_local != prim->ifa_local)
continue;
}
} else {
if (prim->ifa_local != ifa1->ifa_local)
continue;
prim1 = ifa1;
if (prim != prim1)
same_prefsrc = 1;
}
if (ifa->ifa_local == ifa1->ifa_local)
ok |= LOCAL_OK;
if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
ok |= BRD_OK;
if (brd == ifa1->ifa_broadcast)
ok |= BRD1_OK;
if (any == ifa1->ifa_broadcast)
ok |= BRD0_OK;
/* primary has network specific broadcasts */
if (prim1 == ifa1 && ifa1->ifa_prefixlen < 31) {
__be32 brd1 = ifa1->ifa_address | ~ifa1->ifa_mask;
__be32 any1 = ifa1->ifa_address & ifa1->ifa_mask;
if (!ipv4_is_zeronet(any1)) {
if (ifa->ifa_broadcast == brd1 ||
ifa->ifa_broadcast == any1)
ok |= BRD_OK;
if (brd == brd1 || brd == any1)
ok |= BRD1_OK;
if (any == brd1 || any == any1)
ok |= BRD0_OK;
}
}
}
no_promotions:
if (!(ok & BRD_OK))
fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
if (subnet && ifa->ifa_prefixlen < 31) {
if (!(ok & BRD1_OK))
fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
if (!(ok & BRD0_OK))
fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
}
if (!(ok & LOCAL_OK)) {
unsigned int addr_type;
fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
/* Check, that this local address finally disappeared. */
addr_type = inet_addr_type_dev_table(dev_net(dev), dev,
ifa->ifa_local);
if (gone && addr_type != RTN_LOCAL) {
/* And the last, but not the least thing.
* We must flush stray FIB entries.
*
* First of all, we scan fib_info list searching
* for stray nexthop entries, then ignite fib_flush.
*/
if (fib_sync_down_addr(dev, ifa->ifa_local))
fib_flush(dev_net(dev));
}
}
#undef LOCAL_OK
#undef BRD_OK
#undef BRD0_OK
#undef BRD1_OK
}
static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
{
struct fib_result res;
struct flowi4 fl4 = {
.flowi4_mark = frn->fl_mark,
.daddr = frn->fl_addr,
.flowi4_tos = frn->fl_tos,
.flowi4_scope = frn->fl_scope,
};
struct fib_table *tb;
rcu_read_lock();
tb = fib_get_table(net, frn->tb_id_in);
frn->err = -ENOENT;
if (tb) {
local_bh_disable();
frn->tb_id = tb->tb_id;
frn->err = fib_table_lookup(tb, &fl4, &res, FIB_LOOKUP_NOREF);
if (!frn->err) {
frn->prefixlen = res.prefixlen;
frn->nh_sel = res.nh_sel;
frn->type = res.type;
frn->scope = res.scope;
}
local_bh_enable();
}
rcu_read_unlock();
}
static void nl_fib_input(struct sk_buff *skb)
{
struct net *net;
struct fib_result_nl *frn;
struct nlmsghdr *nlh;
u32 portid;
net = sock_net(skb->sk);
nlh = nlmsg_hdr(skb);
if (skb->len < nlmsg_total_size(sizeof(*frn)) ||
skb->len < nlh->nlmsg_len ||
nlmsg_len(nlh) < sizeof(*frn))
return;
skb = netlink_skb_clone(skb, GFP_KERNEL);
if (!skb)
return;
nlh = nlmsg_hdr(skb);
frn = (struct fib_result_nl *) nlmsg_data(nlh);
nl_fib_lookup(net, frn);
portid = NETLINK_CB(skb).portid; /* netlink portid */
NETLINK_CB(skb).portid = 0; /* from kernel */
NETLINK_CB(skb).dst_group = 0; /* unicast */
netlink_unicast(net->ipv4.fibnl, skb, portid, MSG_DONTWAIT);
}
static int __net_init nl_fib_lookup_init(struct net *net)
{
struct sock *sk;
struct netlink_kernel_cfg cfg = {
.input = nl_fib_input,
};
sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
if (!sk)
return -EAFNOSUPPORT;
net->ipv4.fibnl = sk;
return 0;
}
static void nl_fib_lookup_exit(struct net *net)
{
netlink_kernel_release(net->ipv4.fibnl);
net->ipv4.fibnl = NULL;
}
static void fib_disable_ip(struct net_device *dev, unsigned long event,
bool force)
{
if (fib_sync_down_dev(dev, event, force))
fib_flush(dev_net(dev));
else
rt_cache_flush(dev_net(dev));
arp_ifdown(dev);
}
static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct in_ifaddr *ifa = (struct in_ifaddr *)ptr;
struct net_device *dev = ifa->ifa_dev->dev;
struct net *net = dev_net(dev);
switch (event) {
case NETDEV_UP:
fib_add_ifaddr(ifa);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_sync_up(dev, RTNH_F_DEAD);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(dev_net(dev));
break;
case NETDEV_DOWN:
fib_del_ifaddr(ifa, NULL);
atomic_inc(&net->ipv4.dev_addr_genid);
if (!ifa->ifa_dev->ifa_list) {
/* Last address was deleted from this interface.
* Disable IP.
*/
fib_disable_ip(dev, event, true);
} else {
rt_cache_flush(dev_net(dev));
}
break;
}
return NOTIFY_DONE;
}
static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct netdev_notifier_changeupper_info *info;
struct in_device *in_dev;
struct net *net = dev_net(dev);
unsigned int flags;
if (event == NETDEV_UNREGISTER) {
fib_disable_ip(dev, event, true);
rt_flush_dev(dev);
return NOTIFY_DONE;
}
in_dev = __in_dev_get_rtnl(dev);
if (!in_dev)
return NOTIFY_DONE;
switch (event) {
case NETDEV_UP:
for_ifa(in_dev) {
fib_add_ifaddr(ifa);
} endfor_ifa(in_dev);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_sync_up(dev, RTNH_F_DEAD);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(net);
break;
case NETDEV_DOWN:
fib_disable_ip(dev, event, false);
break;
case NETDEV_CHANGE:
flags = dev_get_flags(dev);
if (flags & (IFF_RUNNING | IFF_LOWER_UP))
fib_sync_up(dev, RTNH_F_LINKDOWN);
else
fib_sync_down_dev(dev, event, false);
/* fall through */
case NETDEV_CHANGEMTU:
rt_cache_flush(net);
break;
case NETDEV_CHANGEUPPER:
info = ptr;
/* flush all routes if dev is linked to or unlinked from
* an L3 master device (e.g., VRF)
*/
if (info->upper_dev && netif_is_l3_master(info->upper_dev))
fib_disable_ip(dev, NETDEV_DOWN, true);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block fib_inetaddr_notifier = {
.notifier_call = fib_inetaddr_event,
};
static struct notifier_block fib_netdev_notifier = {
.notifier_call = fib_netdev_event,
};
static int __net_init ip_fib_net_init(struct net *net)
{
int err;
size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
err = fib4_notifier_init(net);
if (err)
return err;
/* Avoid false sharing : Use at least a full cache line */
size = max_t(size_t, size, L1_CACHE_BYTES);
net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
if (!net->ipv4.fib_table_hash) {
err = -ENOMEM;
goto err_table_hash_alloc;
}
err = fib4_rules_init(net);
if (err < 0)
goto err_rules_init;
return 0;
err_rules_init:
kfree(net->ipv4.fib_table_hash);
err_table_hash_alloc:
fib4_notifier_exit(net);
return err;
}
static void ip_fib_net_exit(struct net *net)
{
unsigned int i;
rtnl_lock();
#ifdef CONFIG_IP_MULTIPLE_TABLES
RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
#endif
for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
struct hlist_head *head = &net->ipv4.fib_table_hash[i];
struct hlist_node *tmp;
struct fib_table *tb;
hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
hlist_del(&tb->tb_hlist);
fib_table_flush(net, tb);
fib_free_table(tb);
}
}
#ifdef CONFIG_IP_MULTIPLE_TABLES
fib4_rules_exit(net);
#endif
rtnl_unlock();
kfree(net->ipv4.fib_table_hash);
fib4_notifier_exit(net);
}
static int __net_init fib_net_init(struct net *net)
{
int error;
#ifdef CONFIG_IP_ROUTE_CLASSID
net->ipv4.fib_num_tclassid_users = 0;
#endif
error = ip_fib_net_init(net);
if (error < 0)
goto out;
error = nl_fib_lookup_init(net);
if (error < 0)
goto out_nlfl;
error = fib_proc_init(net);
if (error < 0)
goto out_proc;
out:
return error;
out_proc:
nl_fib_lookup_exit(net);
out_nlfl:
ip_fib_net_exit(net);
goto out;
}
static void __net_exit fib_net_exit(struct net *net)
{
fib_proc_exit(net);
nl_fib_lookup_exit(net);
ip_fib_net_exit(net);
}
static struct pernet_operations fib_net_ops = {
.init = fib_net_init,
.exit = fib_net_exit,
};
void __init ip_fib_init(void)
{
fib_trie_init();
register_pernet_subsys(&fib_net_ops);
register_netdevice_notifier(&fib_netdev_notifier);
register_inetaddr_notifier(&fib_inetaddr_notifier);
rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, 0);
rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, 0);
rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, 0);
}
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