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linux/net/ipv4/fib_frontend.c

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/*
* 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;
}
static bool fib4_has_custom_rules(struct net *net)
{
return false;
}
#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;
}
static bool fib4_has_custom_rules(struct net *net)
{
return net->ipv4.fib_has_custom_rules;
}
#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;
/* with custom local routes in place, checking local addresses
* only will be too optimistic, with custom rules, checking
* local addresses only can be too strict, e.g. due to vrf
*/
if (net->ipv4.fib_has_custom_local_routes ||
fib4_has_custom_rules(net))
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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