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linux/net/ipv4/fib_frontend.c
David S. Miller 35ebf65e85 ipv4: Create and use fib_compute_spec_dst() helper. 
The specific destination is the host we direct unicast replies to.
Usually this is the original packet source address, but if we are
responding to a multicast or broadcast packet we have to use something
different.

Specifically we must use the source address we would use if we were to
send a packet to the unicast source of the original packet.

The routing cache precomputes this value, but we want to remove that
precomputation because it creates a hard dependency on the expensive
rpfilter source address validation which we'd like to make cheaper.

There are only three places where this matters:

1) ICMP replies.

2) pktinfo CMSG

3) IP options

Now there will be no real users of rt->rt_spec_dst and we can simply
remove it altogether.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-28 03:59:11 -07:00

1164 lines
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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 <asm/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/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>
#ifndef CONFIG_IP_MULTIPLE_TABLES
static int __net_init fib4_rules_init(struct net *net)
{
struct fib_table *local_table, *main_table;
local_table = fib_trie_table(RT_TABLE_LOCAL);
if (local_table == NULL)
return -ENOMEM;
main_table = fib_trie_table(RT_TABLE_MAIN);
if (main_table == NULL)
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:
kfree(local_table);
return -ENOMEM;
}
#else
struct fib_table *fib_new_table(struct net *net, u32 id)
{
struct fib_table *tb;
unsigned int h;
if (id == 0)
id = RT_TABLE_MAIN;
tb = fib_get_table(net, id);
if (tb)
return tb;
tb = fib_trie_table(id);
if (!tb)
return NULL;
h = id & (FIB_TABLE_HASHSZ - 1);
hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
return tb;
}
struct fib_table *fib_get_table(struct net *net, u32 id)
{
struct fib_table *tb;
struct hlist_node *node;
struct hlist_head *head;
unsigned int h;
if (id == 0)
id = RT_TABLE_MAIN;
h = id & (FIB_TABLE_HASHSZ - 1);
rcu_read_lock();
head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
if (tb->tb_id == id) {
rcu_read_unlock();
return tb;
}
}
rcu_read_unlock();
return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */
static void fib_flush(struct net *net)
{
int flushed = 0;
struct fib_table *tb;
struct hlist_node *node;
struct hlist_head *head;
unsigned int h;
for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
head = &net->ipv4.fib_table_hash[h];
hlist_for_each_entry(tb, node, head, tb_hlist)
flushed += fib_table_flush(tb);
}
if (flushed)
rt_cache_flush(net, -1);
}
/*
* 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)
{
struct flowi4 fl4 = { .daddr = addr };
struct fib_result res;
unsigned int ret = RTN_BROADCAST;
struct fib_table *local_table;
if (ipv4_is_zeronet(addr) || ipv4_is_lbcast(addr))
return RTN_BROADCAST;
if (ipv4_is_multicast(addr))
return RTN_MULTICAST;
#ifdef CONFIG_IP_MULTIPLE_TABLES
res.r = NULL;
#endif
local_table = fib_get_table(net, RT_TABLE_LOCAL);
if (local_table) {
ret = RTN_UNICAST;
rcu_read_lock();
if (!fib_table_lookup(local_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(struct net *net, __be32 addr)
{
return __inet_dev_addr_type(net, NULL, addr);
}
EXPORT_SYMBOL(inet_addr_type);
unsigned int inet_dev_addr_type(struct net *net, const struct net_device *dev,
__be32 addr)
{
return __inet_dev_addr_type(net, dev, addr);
}
EXPORT_SYMBOL(inet_dev_addr_type);
__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 flowi4 fl4;
struct net *net;
if (skb->pkt_type != PACKET_BROADCAST &&
skb->pkt_type != PACKET_MULTICAST)
return ip_hdr(skb)->daddr;
in_dev = __in_dev_get_rcu(dev);
BUG_ON(!in_dev);
fl4.flowi4_oif = 0;
fl4.flowi4_iif = 0;
fl4.daddr = ip_hdr(skb)->saddr;
fl4.saddr = ip_hdr(skb)->daddr;
fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos);
fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
net = dev_net(dev);
if (!fib_lookup(net, &fl4, &res))
return FIB_RES_PREFSRC(net, res);
else
return inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
}
/* 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()
*/
int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, u8 tos,
int oif, struct net_device *dev, __be32 *spec_dst,
u32 *itag)
{
struct in_device *in_dev;
struct flowi4 fl4;
struct fib_result res;
int no_addr, rpf, accept_local;
bool dev_match;
int ret;
struct net *net;
fl4.flowi4_oif = 0;
fl4.flowi4_iif = oif;
fl4.daddr = src;
fl4.saddr = dst;
fl4.flowi4_tos = tos;
fl4.flowi4_scope = RT_SCOPE_UNIVERSE;
no_addr = rpf = accept_local = 0;
in_dev = __in_dev_get_rcu(dev);
if (in_dev) {
no_addr = in_dev->ifa_list == NULL;
/* Ignore rp_filter for packets protected by IPsec. */
rpf = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(in_dev);
accept_local = IN_DEV_ACCEPT_LOCAL(in_dev);
fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0;
}
if (in_dev == NULL)
goto e_inval;
net = dev_net(dev);
if (fib_lookup(net, &fl4, &res))
goto last_resort;
if (res.type != RTN_UNICAST) {
if (res.type != RTN_LOCAL || !accept_local)
goto e_inval;
}
*spec_dst = FIB_RES_PREFSRC(net, res);
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 (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) == 0) {
if (res.type == RTN_UNICAST) {
*spec_dst = FIB_RES_PREFSRC(net, res);
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
}
}
return ret;
last_resort:
if (rpf)
goto e_rpf;
*spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
*itag = 0;
return 0;
e_inval:
return -EINVAL;
e_rpf:
return -EXDEV;
}
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;
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 == NULL)
return -ENODEV;
cfg->fc_prefsrc = ifa->ifa_local;
}
}
addr = sk_extract_addr(&rt->rt_gateway);
if (rt->rt_gateway.sa_family == AF_INET && addr) {
cfg->fc_gw = addr;
if (rt->rt_flags & RTF_GATEWAY &&
inet_addr_type(net, addr) == 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 == NULL)
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 (!capable(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(tb, &cfg);
else
err = -ESRCH;
} else {
tb = fib_new_table(net, cfg.fc_table);
if (tb)
err = fib_table_insert(tb, &cfg);
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 },
};
static int rtm_to_fib_config(struct net *net, struct sk_buff *skb,
struct nlmsghdr *nlh, struct fib_config *cfg)
{
struct nlattr *attr;
int err, remaining;
struct rtmsg *rtm;
err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
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.pid = NETLINK_CB(skb).pid;
cfg->fc_nlinfo.nlh = nlh;
cfg->fc_nlinfo.nl_net = net;
if (cfg->fc_type > RTN_MAX) {
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:
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;
}
}
return 0;
errout:
return err;
}
static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
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);
if (err < 0)
goto errout;
tb = fib_get_table(net, cfg.fc_table);
if (tb == NULL) {
err = -ESRCH;
goto errout;
}
err = fib_table_delete(tb, &cfg);
errout:
return err;
}
static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
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);
if (err < 0)
goto errout;
tb = fib_new_table(net, cfg.fc_table);
if (tb == NULL) {
err = -ENOBUFS;
goto errout;
}
err = fib_table_insert(tb, &cfg);
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_node *node;
struct hlist_head *head;
int dumped = 0;
if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
return ip_rt_dump(skb, cb);
s_h = cb->args[0];
s_e = cb->args[1];
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(tb, node, head, tb_hlist) {
if (e < s_e)
goto next;
if (dumped)
memset(&cb->args[2], 0, sizeof(cb->args) -
2 * sizeof(cb->args[0]));
if (fib_table_dump(tb, skb, cb) < 0)
goto out;
dumped = 1;
next:
e++;
}
}
out:
cb->args[1] = e;
cb->args[0] = h;
return skb->len;
}
/* 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);
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 (type == RTN_UNICAST)
tb = fib_new_table(net, RT_TABLE_MAIN);
else
tb = fib_new_table(net, RT_TABLE_LOCAL);
if (tb == NULL)
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(tb, &cfg);
else
fib_table_delete(tb, &cfg);
}
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 == NULL) {
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)) {
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 == NULL) {
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)) {
fib_magic(RTM_DELROUTE,
dev->flags & IFF_LOOPBACK ? RTN_LOCAL : RTN_UNICAST,
any, ifa->ifa_prefixlen, prim);
subnet = 1;
}
/* 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;
}
}
}
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)) {
fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);
/* Check, that this local address finally disappeared. */
if (gone &&
inet_addr_type(dev_net(dev), ifa->ifa_local) != 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_net(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 fib_result_nl *frn, struct fib_table *tb)
{
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,
};
#ifdef CONFIG_IP_MULTIPLE_TABLES
res.r = NULL;
#endif
frn->err = -ENOENT;
if (tb) {
local_bh_disable();
frn->tb_id = tb->tb_id;
rcu_read_lock();
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;
}
rcu_read_unlock();
local_bh_enable();
}
}
static void nl_fib_input(struct sk_buff *skb)
{
struct net *net;
struct fib_result_nl *frn;
struct nlmsghdr *nlh;
struct fib_table *tb;
u32 pid;
net = sock_net(skb->sk);
nlh = nlmsg_hdr(skb);
if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn)))
return;
skb = skb_clone(skb, GFP_KERNEL);
if (skb == NULL)
return;
nlh = nlmsg_hdr(skb);
frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
tb = fib_get_table(net, frn->tb_id_in);
nl_fib_lookup(frn, tb);
pid = NETLINK_CB(skb).pid; /* pid of sending process */
NETLINK_CB(skb).pid = 0; /* from kernel */
NETLINK_CB(skb).dst_group = 0; /* unicast */
netlink_unicast(net->ipv4.fibnl, skb, pid, MSG_DONTWAIT);
}
static int __net_init nl_fib_lookup_init(struct net *net)
{
struct sock *sk;
sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, 0,
nl_fib_input, NULL, THIS_MODULE);
if (sk == NULL)
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, int force, int delay)
{
if (fib_sync_down_dev(dev, force))
fib_flush(dev_net(dev));
rt_cache_flush(dev_net(dev), delay);
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);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(dev_net(dev), -1);
break;
case NETDEV_DOWN:
fib_del_ifaddr(ifa, NULL);
atomic_inc(&net->ipv4.dev_addr_genid);
if (ifa->ifa_dev->ifa_list == NULL) {
/* Last address was deleted from this interface.
* Disable IP.
*/
fib_disable_ip(dev, 1, 0);
} else {
rt_cache_flush(dev_net(dev), -1);
}
break;
}
return NOTIFY_DONE;
}
static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
struct in_device *in_dev = __in_dev_get_rtnl(dev);
struct net *net = dev_net(dev);
if (event == NETDEV_UNREGISTER) {
fib_disable_ip(dev, 2, -1);
return NOTIFY_DONE;
}
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);
#endif
atomic_inc(&net->ipv4.dev_addr_genid);
rt_cache_flush(dev_net(dev), -1);
break;
case NETDEV_DOWN:
fib_disable_ip(dev, 0, 0);
break;
case NETDEV_CHANGEMTU:
case NETDEV_CHANGE:
rt_cache_flush(dev_net(dev), 0);
break;
case NETDEV_UNREGISTER_BATCH:
/* The batch unregister is only called on the first
* device in the list of devices being unregistered.
* Therefore we should not pass dev_net(dev) in here.
*/
rt_cache_flush_batch(NULL);
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;
/* 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 == NULL)
return -ENOMEM;
err = fib4_rules_init(net);
if (err < 0)
goto fail;
return 0;
fail:
kfree(net->ipv4.fib_table_hash);
return err;
}
static void ip_fib_net_exit(struct net *net)
{
unsigned int i;
#ifdef CONFIG_IP_MULTIPLE_TABLES
fib4_rules_exit(net);
#endif
rtnl_lock();
for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
struct fib_table *tb;
struct hlist_head *head;
struct hlist_node *node, *tmp;
head = &net->ipv4.fib_table_hash[i];
hlist_for_each_entry_safe(tb, node, tmp, head, tb_hlist) {
hlist_del(node);
fib_table_flush(tb);
fib_free_table(tb);
}
}
rtnl_unlock();
kfree(net->ipv4.fib_table_hash);
}
static int __net_init fib_net_init(struct net *net)
{
int error;
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)
{
rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL, NULL);
rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL, NULL);
rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib, NULL);
register_pernet_subsys(&fib_net_ops);
register_netdevice_notifier(&fib_netdev_notifier);
register_inetaddr_notifier(&fib_inetaddr_notifier);
fib_trie_init();
}
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