linux/net/ipv4/xfrm4_policy.c
David Ahern 77d5bc7e6a ipv4: Revert removal of rt_uses_gateway
Julian noted that rt_uses_gateway has a more subtle use than 'is gateway
set':
    https://lore.kernel.org/netdev/alpine.LFD.2.21.1909151104060.2546@ja.home.ssi.bg/

Revert that part of the commit referenced in the Fixes tag.

Currently, there are no u8 holes in 'struct rtable'. There is a 4-byte hole
in the second cacheline which contains the gateway declaration. So move
rt_gw_family down to the gateway declarations since they are always used
together, and then re-use that u8 for rt_uses_gateway. End result is that
rtable size is unchanged.

Fixes: 1550c17193 ("ipv4: Prepare rtable for IPv6 gateway")
Reported-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-09-20 18:23:33 -07:00

261 lines
5.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* xfrm4_policy.c
*
* Changes:
* Kazunori MIYAZAWA @USAGI
* YOSHIFUJI Hideaki @USAGI
* Split up af-specific portion
*
*/
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/inetdevice.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/l3mdev.h>
static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
int tos, int oif,
const xfrm_address_t *saddr,
const xfrm_address_t *daddr,
u32 mark)
{
struct rtable *rt;
memset(fl4, 0, sizeof(*fl4));
fl4->daddr = daddr->a4;
fl4->flowi4_tos = tos;
fl4->flowi4_oif = l3mdev_master_ifindex_by_index(net, oif);
fl4->flowi4_mark = mark;
if (saddr)
fl4->saddr = saddr->a4;
fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF;
rt = __ip_route_output_key(net, fl4);
if (!IS_ERR(rt))
return &rt->dst;
return ERR_CAST(rt);
}
static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
const xfrm_address_t *saddr,
const xfrm_address_t *daddr,
u32 mark)
{
struct flowi4 fl4;
return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr, mark);
}
static int xfrm4_get_saddr(struct net *net, int oif,
xfrm_address_t *saddr, xfrm_address_t *daddr,
u32 mark)
{
struct dst_entry *dst;
struct flowi4 fl4;
dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr, mark);
if (IS_ERR(dst))
return -EHOSTUNREACH;
saddr->a4 = fl4.saddr;
dst_release(dst);
return 0;
}
static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
const struct flowi *fl)
{
struct rtable *rt = (struct rtable *)xdst->route;
const struct flowi4 *fl4 = &fl->u.ip4;
xdst->u.rt.rt_iif = fl4->flowi4_iif;
xdst->u.dst.dev = dev;
dev_hold(dev);
/* Sheit... I remember I did this right. Apparently,
* it was magically lost, so this code needs audit */
xdst->u.rt.rt_is_input = rt->rt_is_input;
xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
RTCF_LOCAL);
xdst->u.rt.rt_type = rt->rt_type;
xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
xdst->u.rt.rt_gw_family = rt->rt_gw_family;
if (rt->rt_gw_family == AF_INET)
xdst->u.rt.rt_gw4 = rt->rt_gw4;
else if (rt->rt_gw_family == AF_INET6)
xdst->u.rt.rt_gw6 = rt->rt_gw6;
xdst->u.rt.rt_pmtu = rt->rt_pmtu;
xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
INIT_LIST_HEAD(&xdst->u.rt.rt_uncached);
rt_add_uncached_list(&xdst->u.rt);
return 0;
}
static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
struct sk_buff *skb, u32 mtu)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
struct dst_entry *path = xdst->route;
path->ops->update_pmtu(path, sk, skb, mtu);
}
static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
struct sk_buff *skb)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
struct dst_entry *path = xdst->route;
path->ops->redirect(path, sk, skb);
}
static void xfrm4_dst_destroy(struct dst_entry *dst)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
dst_destroy_metrics_generic(dst);
if (xdst->u.rt.rt_uncached_list)
rt_del_uncached_list(&xdst->u.rt);
xfrm_dst_destroy(xdst);
}
static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
if (!unregister)
return;
xfrm_dst_ifdown(dst, dev);
}
static struct dst_ops xfrm4_dst_ops_template = {
.family = AF_INET,
.update_pmtu = xfrm4_update_pmtu,
.redirect = xfrm4_redirect,
.cow_metrics = dst_cow_metrics_generic,
.destroy = xfrm4_dst_destroy,
.ifdown = xfrm4_dst_ifdown,
.local_out = __ip_local_out,
.gc_thresh = 32768,
};
static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
.dst_ops = &xfrm4_dst_ops_template,
.dst_lookup = xfrm4_dst_lookup,
.get_saddr = xfrm4_get_saddr,
.fill_dst = xfrm4_fill_dst,
.blackhole_route = ipv4_blackhole_route,
};
#ifdef CONFIG_SYSCTL
static struct ctl_table xfrm4_policy_table[] = {
{
.procname = "xfrm4_gc_thresh",
.data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static __net_init int xfrm4_net_sysctl_init(struct net *net)
{
struct ctl_table *table;
struct ctl_table_header *hdr;
table = xfrm4_policy_table;
if (!net_eq(net, &init_net)) {
table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL);
if (!table)
goto err_alloc;
table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
}
hdr = register_net_sysctl(net, "net/ipv4", table);
if (!hdr)
goto err_reg;
net->ipv4.xfrm4_hdr = hdr;
return 0;
err_reg:
if (!net_eq(net, &init_net))
kfree(table);
err_alloc:
return -ENOMEM;
}
static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
{
struct ctl_table *table;
if (!net->ipv4.xfrm4_hdr)
return;
table = net->ipv4.xfrm4_hdr->ctl_table_arg;
unregister_net_sysctl_table(net->ipv4.xfrm4_hdr);
if (!net_eq(net, &init_net))
kfree(table);
}
#else /* CONFIG_SYSCTL */
static inline int xfrm4_net_sysctl_init(struct net *net)
{
return 0;
}
static inline void xfrm4_net_sysctl_exit(struct net *net)
{
}
#endif
static int __net_init xfrm4_net_init(struct net *net)
{
int ret;
memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
sizeof(xfrm4_dst_ops_template));
ret = dst_entries_init(&net->xfrm.xfrm4_dst_ops);
if (ret)
return ret;
ret = xfrm4_net_sysctl_init(net);
if (ret)
dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
return ret;
}
static void __net_exit xfrm4_net_exit(struct net *net)
{
xfrm4_net_sysctl_exit(net);
dst_entries_destroy(&net->xfrm.xfrm4_dst_ops);
}
static struct pernet_operations __net_initdata xfrm4_net_ops = {
.init = xfrm4_net_init,
.exit = xfrm4_net_exit,
};
static void __init xfrm4_policy_init(void)
{
xfrm_policy_register_afinfo(&xfrm4_policy_afinfo, AF_INET);
}
void __init xfrm4_init(void)
{
xfrm4_state_init();
xfrm4_policy_init();
xfrm4_protocol_init();
register_pernet_subsys(&xfrm4_net_ops);
}