Viewing file:  fib_rules.c (11.29 KB) -rw-r--r--
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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: policy rules.
*
* Version: $Id: fib_rules.c,v 1.17 2001/10/31 21:55:54 davem Exp $
*
* 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.
*
* Fixes:
* Rani Assaf : local_rule cannot be deleted
* Marc Boucher : routing by fwmark
*/
#include <linux/config.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.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/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>
#define FRprintk(a...)
struct fib_rule
{
struct fib_rule *r_next;
atomic_t r_clntref;
u32 r_preference;
unsigned char r_table;
unsigned char r_action;
unsigned char r_dst_len;
unsigned char r_src_len;
u32 r_src;
u32 r_srcmask;
u32 r_dst;
u32 r_dstmask;
u32 r_srcmap;
u8 r_flags;
u8 r_tos;
#ifdef CONFIG_IP_ROUTE_FWMARK
u32 r_fwmark;
#endif
int r_ifindex;
#ifdef CONFIG_NET_CLS_ROUTE
__u32 r_tclassid;
#endif
char r_ifname[IFNAMSIZ];
int r_dead;
};
static struct fib_rule default_rule = {
r_clntref: ATOMIC_INIT(2),
r_preference: 0x7FFF,
r_table: RT_TABLE_DEFAULT,
r_action: RTN_UNICAST,
};
static struct fib_rule main_rule = {
r_next: &default_rule,
r_clntref: ATOMIC_INIT(2),
r_preference: 0x7FFE,
r_table: RT_TABLE_MAIN,
r_action: RTN_UNICAST,
};
static struct fib_rule local_rule = {
r_next: &main_rule,
r_clntref: ATOMIC_INIT(2),
r_table: RT_TABLE_LOCAL,
r_action: RTN_UNICAST,
};
static struct fib_rule *fib_rules = &local_rule;
static rwlock_t fib_rules_lock = RW_LOCK_UNLOCKED;
int inet_rtm_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
struct rtattr **rta = arg;
struct rtmsg *rtm = NLMSG_DATA(nlh);
struct fib_rule *r, **rp;
int err = -ESRCH;
for (rp=&fib_rules; (r=*rp) != NULL; rp=&r->r_next) {
if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 4) == 0) &&
rtm->rtm_src_len == r->r_src_len &&
rtm->rtm_dst_len == r->r_dst_len &&
(!rta[RTA_DST-1] || memcmp(RTA_DATA(rta[RTA_DST-1]), &r->r_dst, 4) == 0) &&
rtm->rtm_tos == r->r_tos &&
#ifdef CONFIG_IP_ROUTE_FWMARK
(!rta[RTA_PROTOINFO-1] || memcmp(RTA_DATA(rta[RTA_PROTOINFO-1]), &r->r_fwmark, 4) == 0) &&
#endif
(!rtm->rtm_type || rtm->rtm_type == r->r_action) &&
(!rta[RTA_PRIORITY-1] || memcmp(RTA_DATA(rta[RTA_PRIORITY-1]), &r->r_preference, 4) == 0) &&
(!rta[RTA_IIF-1] || strcmp(RTA_DATA(rta[RTA_IIF-1]), r->r_ifname) == 0) &&
(!rtm->rtm_table || (r && rtm->rtm_table == r->r_table))) {
err = -EPERM;
if (r == &local_rule)
break;
write_lock_bh(&fib_rules_lock);
*rp = r->r_next;
r->r_dead = 1;
write_unlock_bh(&fib_rules_lock);
fib_rule_put(r);
err = 0;
break;
}
}
return err;
}
/* Allocate new unique table id */
static struct fib_table *fib_empty_table(void)
{
int id;
for (id = 1; id <= RT_TABLE_MAX; id++)
if (fib_tables[id] == NULL)
return __fib_new_table(id);
return NULL;
}
void fib_rule_put(struct fib_rule *r)
{
if (atomic_dec_and_test(&r->r_clntref)) {
if (r->r_dead)
kfree(r);
else
printk("Freeing alive rule %p\n", r);
}
}
int inet_rtm_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
struct rtattr **rta = arg;
struct rtmsg *rtm = NLMSG_DATA(nlh);
struct fib_rule *r, *new_r, **rp;
unsigned char table_id;
if (rtm->rtm_src_len > 32 || rtm->rtm_dst_len > 32 ||
(rtm->rtm_tos & ~IPTOS_TOS_MASK))
return -EINVAL;
if (rta[RTA_IIF-1] && RTA_PAYLOAD(rta[RTA_IIF-1]) > IFNAMSIZ)
return -EINVAL;
table_id = rtm->rtm_table;
if (table_id == RT_TABLE_UNSPEC) {
struct fib_table *table;
if (rtm->rtm_type == RTN_UNICAST || rtm->rtm_type == RTN_NAT) {
if ((table = fib_empty_table()) == NULL)
return -ENOBUFS;
table_id = table->tb_id;
}
}
new_r = kmalloc(sizeof(*new_r), GFP_KERNEL);
if (!new_r)
return -ENOMEM;
memset(new_r, 0, sizeof(*new_r));
if (rta[RTA_SRC-1])
memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 4);
if (rta[RTA_DST-1])
memcpy(&new_r->r_dst, RTA_DATA(rta[RTA_DST-1]), 4);
if (rta[RTA_GATEWAY-1])
memcpy(&new_r->r_srcmap, RTA_DATA(rta[RTA_GATEWAY-1]), 4);
new_r->r_src_len = rtm->rtm_src_len;
new_r->r_dst_len = rtm->rtm_dst_len;
new_r->r_srcmask = inet_make_mask(rtm->rtm_src_len);
new_r->r_dstmask = inet_make_mask(rtm->rtm_dst_len);
new_r->r_tos = rtm->rtm_tos;
#ifdef CONFIG_IP_ROUTE_FWMARK
if (rta[RTA_PROTOINFO-1])
memcpy(&new_r->r_fwmark, RTA_DATA(rta[RTA_PROTOINFO-1]), 4);
#endif
new_r->r_action = rtm->rtm_type;
new_r->r_flags = rtm->rtm_flags;
if (rta[RTA_PRIORITY-1])
memcpy(&new_r->r_preference, RTA_DATA(rta[RTA_PRIORITY-1]), 4);
new_r->r_table = table_id;
if (rta[RTA_IIF-1]) {
struct net_device *dev;
memcpy(new_r->r_ifname, RTA_DATA(rta[RTA_IIF-1]), IFNAMSIZ);
new_r->r_ifname[IFNAMSIZ-1] = 0;
new_r->r_ifindex = -1;
dev = __dev_get_by_name(new_r->r_ifname);
if (dev)
new_r->r_ifindex = dev->ifindex;
}
#ifdef CONFIG_NET_CLS_ROUTE
if (rta[RTA_FLOW-1])
memcpy(&new_r->r_tclassid, RTA_DATA(rta[RTA_FLOW-1]), 4);
#endif
rp = &fib_rules;
if (!new_r->r_preference) {
r = fib_rules;
if (r && (r = r->r_next) != NULL) {
rp = &fib_rules->r_next;
if (r->r_preference)
new_r->r_preference = r->r_preference - 1;
}
}
while ( (r = *rp) != NULL ) {
if (r->r_preference > new_r->r_preference)
break;
rp = &r->r_next;
}
new_r->r_next = r;
atomic_inc(&new_r->r_clntref);
write_lock_bh(&fib_rules_lock);
*rp = new_r;
write_unlock_bh(&fib_rules_lock);
return 0;
}
u32 fib_rules_map_destination(u32 daddr, struct fib_result *res)
{
u32 mask = inet_make_mask(res->prefixlen);
return (daddr&~mask)|res->fi->fib_nh->nh_gw;
}
u32 fib_rules_policy(u32 saddr, struct fib_result *res, unsigned *flags)
{
struct fib_rule *r = res->r;
if (r->r_action == RTN_NAT) {
int addrtype = inet_addr_type(r->r_srcmap);
if (addrtype == RTN_NAT) {
/* Packet is from translated source; remember it */
saddr = (saddr&~r->r_srcmask)|r->r_srcmap;
*flags |= RTCF_SNAT;
} else if (addrtype == RTN_LOCAL || r->r_srcmap == 0) {
/* Packet is from masqueraded source; remember it */
saddr = r->r_srcmap;
*flags |= RTCF_MASQ;
}
}
return saddr;
}
#ifdef CONFIG_NET_CLS_ROUTE
u32 fib_rules_tclass(struct fib_result *res)
{
if (res->r)
return res->r->r_tclassid;
return 0;
}
#endif
static void fib_rules_detach(struct net_device *dev)
{
struct fib_rule *r;
for (r=fib_rules; r; r=r->r_next) {
if (r->r_ifindex == dev->ifindex) {
write_lock_bh(&fib_rules_lock);
r->r_ifindex = -1;
write_unlock_bh(&fib_rules_lock);
}
}
}
static void fib_rules_attach(struct net_device *dev)
{
struct fib_rule *r;
for (r=fib_rules; r; r=r->r_next) {
if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
write_lock_bh(&fib_rules_lock);
r->r_ifindex = dev->ifindex;
write_unlock_bh(&fib_rules_lock);
}
}
}
int fib_lookup(const struct rt_key *key, struct fib_result *res)
{
int err;
struct fib_rule *r, *policy;
struct fib_table *tb;
u32 daddr = key->dst;
u32 saddr = key->src;
FRprintk("Lookup: %u.%u.%u.%u <- %u.%u.%u.%u ",
NIPQUAD(key->dst), NIPQUAD(key->src));
read_lock(&fib_rules_lock);
for (r = fib_rules; r; r=r->r_next) {
if (((saddr^r->r_src) & r->r_srcmask) ||
((daddr^r->r_dst) & r->r_dstmask) ||
#ifdef CONFIG_IP_ROUTE_TOS
(r->r_tos && r->r_tos != key->tos) ||
#endif
#ifdef CONFIG_IP_ROUTE_FWMARK
(r->r_fwmark && r->r_fwmark != key->fwmark) ||
#endif
(r->r_ifindex && r->r_ifindex != key->iif))
continue;
FRprintk("tb %d r %d ", r->r_table, r->r_action);
switch (r->r_action) {
case RTN_UNICAST:
case RTN_NAT:
policy = r;
break;
case RTN_UNREACHABLE:
read_unlock(&fib_rules_lock);
return -ENETUNREACH;
default:
case RTN_BLACKHOLE:
read_unlock(&fib_rules_lock);
return -EINVAL;
case RTN_PROHIBIT:
read_unlock(&fib_rules_lock);
return -EACCES;
}
if ((tb = fib_get_table(r->r_table)) == NULL)
continue;
err = tb->tb_lookup(tb, key, res);
if (err == 0) {
res->r = policy;
if (policy)
atomic_inc(&policy->r_clntref);
read_unlock(&fib_rules_lock);
return 0;
}
if (err < 0 && err != -EAGAIN) {
read_unlock(&fib_rules_lock);
return err;
}
}
FRprintk("FAILURE\n");
read_unlock(&fib_rules_lock);
return -ENETUNREACH;
}
void fib_select_default(const struct rt_key *key, struct fib_result *res)
{
if (res->r && res->r->r_action == RTN_UNICAST &&
FIB_RES_GW(*res) && FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK) {
struct fib_table *tb;
if ((tb = fib_get_table(res->r->r_table)) != NULL)
tb->tb_select_default(tb, key, res);
}
}
static int fib_rules_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
if (event == NETDEV_UNREGISTER)
fib_rules_detach(dev);
else if (event == NETDEV_REGISTER)
fib_rules_attach(dev);
return NOTIFY_DONE;
}
struct notifier_block fib_rules_notifier = {
notifier_call: fib_rules_event,
};
static __inline__ int inet_fill_rule(struct sk_buff *skb,
struct fib_rule *r,
struct netlink_callback *cb)
{
struct rtmsg *rtm;
struct nlmsghdr *nlh;
unsigned char *b = skb->tail;
nlh = NLMSG_PUT(skb, NETLINK_CREDS(cb->skb)->pid, cb->nlh->nlmsg_seq, RTM_NEWRULE, sizeof(*rtm));
rtm = NLMSG_DATA(nlh);
rtm->rtm_family = AF_INET;
rtm->rtm_dst_len = r->r_dst_len;
rtm->rtm_src_len = r->r_src_len;
rtm->rtm_tos = r->r_tos;
#ifdef CONFIG_IP_ROUTE_FWMARK
if (r->r_fwmark)
RTA_PUT(skb, RTA_PROTOINFO, 4, &r->r_fwmark);
#endif
rtm->rtm_table = r->r_table;
rtm->rtm_protocol = 0;
rtm->rtm_scope = 0;
rtm->rtm_type = r->r_action;
rtm->rtm_flags = r->r_flags;
if (r->r_dst_len)
RTA_PUT(skb, RTA_DST, 4, &r->r_dst);
if (r->r_src_len)
RTA_PUT(skb, RTA_SRC, 4, &r->r_src);
if (r->r_ifname[0])
RTA_PUT(skb, RTA_IIF, IFNAMSIZ, &r->r_ifname);
if (r->r_preference)
RTA_PUT(skb, RTA_PRIORITY, 4, &r->r_preference);
if (r->r_srcmap)
RTA_PUT(skb, RTA_GATEWAY, 4, &r->r_srcmap);
#ifdef CONFIG_NET_CLS_ROUTE
if (r->r_tclassid)
RTA_PUT(skb, RTA_FLOW, 4, &r->r_tclassid);
#endif
nlh->nlmsg_len = skb->tail - b;
return skb->len;
nlmsg_failure:
rtattr_failure:
skb_put(skb, b - skb->tail);
return -1;
}
int inet_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
{
int idx;
int s_idx = cb->args[0];
struct fib_rule *r;
read_lock(&fib_rules_lock);
for (r=fib_rules, idx=0; r; r = r->r_next, idx++) {
if (idx < s_idx)
continue;
if (inet_fill_rule(skb, r, cb) < 0)
break;
}
read_unlock(&fib_rules_lock);
cb->args[0] = idx;
return skb->len;
}
void __init fib_rules_init(void)
{
register_netdevice_notifier(&fib_rules_notifier);
}
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