1// SPDX-License-Identifier: GPL-2.0
2/*
3 * xfrm4_policy.c
4 *
5 * Changes:
6 * Kazunori MIYAZAWA @USAGI
7 * YOSHIFUJI Hideaki @USAGI
8 * Split up af-specific portion
9 *
10 */
11
12#include <linux/err.h>
13#include <linux/kernel.h>
14#include <linux/inetdevice.h>
15#include <net/dst.h>
16#include <net/xfrm.h>
17#include <net/ip.h>
18#include <net/l3mdev.h>
19
20static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4,
21 int tos, int oif,
22 const xfrm_address_t *saddr,
23 const xfrm_address_t *daddr,
24 u32 mark)
25{
26 struct rtable *rt;
27
28 memset(fl4, 0, sizeof(*fl4));
29 fl4->daddr = daddr->a4;
30 fl4->flowi4_tos = tos;
31 fl4->flowi4_l3mdev = l3mdev_master_ifindex_by_index(net, ifindex: oif);
32 fl4->flowi4_mark = mark;
33 if (saddr)
34 fl4->saddr = saddr->a4;
35
36 rt = __ip_route_output_key(net, flp: fl4);
37 if (!IS_ERR(ptr: rt))
38 return &rt->dst;
39
40 return ERR_CAST(ptr: rt);
41}
42
43static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif,
44 const xfrm_address_t *saddr,
45 const xfrm_address_t *daddr,
46 u32 mark)
47{
48 struct flowi4 fl4;
49
50 return __xfrm4_dst_lookup(net, fl4: &fl4, tos, oif, saddr, daddr, mark);
51}
52
53static int xfrm4_get_saddr(struct net *net, int oif,
54 xfrm_address_t *saddr, xfrm_address_t *daddr,
55 u32 mark)
56{
57 struct dst_entry *dst;
58 struct flowi4 fl4;
59
60 dst = __xfrm4_dst_lookup(net, fl4: &fl4, tos: 0, oif, NULL, daddr, mark);
61 if (IS_ERR(ptr: dst))
62 return -EHOSTUNREACH;
63
64 saddr->a4 = fl4.saddr;
65 dst_release(dst);
66 return 0;
67}
68
69static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
70 const struct flowi *fl)
71{
72 struct rtable *rt = (struct rtable *)xdst->route;
73 const struct flowi4 *fl4 = &fl->u.ip4;
74
75 xdst->u.rt.rt_iif = fl4->flowi4_iif;
76
77 xdst->u.dst.dev = dev;
78 netdev_hold(dev, tracker: &xdst->u.dst.dev_tracker, GFP_ATOMIC);
79
80 /* Sheit... I remember I did this right. Apparently,
81 * it was magically lost, so this code needs audit */
82 xdst->u.rt.rt_is_input = rt->rt_is_input;
83 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST |
84 RTCF_LOCAL);
85 xdst->u.rt.rt_type = rt->rt_type;
86 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway;
87 xdst->u.rt.rt_gw_family = rt->rt_gw_family;
88 if (rt->rt_gw_family == AF_INET)
89 xdst->u.rt.rt_gw4 = rt->rt_gw4;
90 else if (rt->rt_gw_family == AF_INET6)
91 xdst->u.rt.rt_gw6 = rt->rt_gw6;
92 xdst->u.rt.rt_pmtu = rt->rt_pmtu;
93 xdst->u.rt.rt_mtu_locked = rt->rt_mtu_locked;
94 rt_add_uncached_list(rt: &xdst->u.rt);
95
96 return 0;
97}
98
99static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk,
100 struct sk_buff *skb, u32 mtu,
101 bool confirm_neigh)
102{
103 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
104 struct dst_entry *path = xdst->route;
105
106 path->ops->update_pmtu(path, sk, skb, mtu, confirm_neigh);
107}
108
109static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk,
110 struct sk_buff *skb)
111{
112 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
113 struct dst_entry *path = xdst->route;
114
115 path->ops->redirect(path, sk, skb);
116}
117
118static void xfrm4_dst_destroy(struct dst_entry *dst)
119{
120 struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
121
122 dst_destroy_metrics_generic(dst);
123 rt_del_uncached_list(rt: &xdst->u.rt);
124 xfrm_dst_destroy(xdst);
125}
126
127static struct dst_ops xfrm4_dst_ops_template = {
128 .family = AF_INET,
129 .update_pmtu = xfrm4_update_pmtu,
130 .redirect = xfrm4_redirect,
131 .cow_metrics = dst_cow_metrics_generic,
132 .destroy = xfrm4_dst_destroy,
133 .ifdown = xfrm_dst_ifdown,
134 .local_out = __ip_local_out,
135 .gc_thresh = 32768,
136};
137
138static const struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
139 .dst_ops = &xfrm4_dst_ops_template,
140 .dst_lookup = xfrm4_dst_lookup,
141 .get_saddr = xfrm4_get_saddr,
142 .fill_dst = xfrm4_fill_dst,
143 .blackhole_route = ipv4_blackhole_route,
144};
145
146#ifdef CONFIG_SYSCTL
147static struct ctl_table xfrm4_policy_table[] = {
148 {
149 .procname = "xfrm4_gc_thresh",
150 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh,
151 .maxlen = sizeof(int),
152 .mode = 0644,
153 .proc_handler = proc_dointvec,
154 },
155 { }
156};
157
158static __net_init int xfrm4_net_sysctl_init(struct net *net)
159{
160 struct ctl_table *table;
161 struct ctl_table_header *hdr;
162
163 table = xfrm4_policy_table;
164 if (!net_eq(net1: net, net2: &init_net)) {
165 table = kmemdup(p: table, size: sizeof(xfrm4_policy_table), GFP_KERNEL);
166 if (!table)
167 goto err_alloc;
168
169 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh;
170 }
171
172 hdr = register_net_sysctl_sz(net, path: "net/ipv4", table,
173 ARRAY_SIZE(xfrm4_policy_table));
174 if (!hdr)
175 goto err_reg;
176
177 net->ipv4.xfrm4_hdr = hdr;
178 return 0;
179
180err_reg:
181 if (!net_eq(net1: net, net2: &init_net))
182 kfree(objp: table);
183err_alloc:
184 return -ENOMEM;
185}
186
187static __net_exit void xfrm4_net_sysctl_exit(struct net *net)
188{
189 struct ctl_table *table;
190
191 if (!net->ipv4.xfrm4_hdr)
192 return;
193
194 table = net->ipv4.xfrm4_hdr->ctl_table_arg;
195 unregister_net_sysctl_table(header: net->ipv4.xfrm4_hdr);
196 if (!net_eq(net1: net, net2: &init_net))
197 kfree(objp: table);
198}
199#else /* CONFIG_SYSCTL */
200static inline int xfrm4_net_sysctl_init(struct net *net)
201{
202 return 0;
203}
204
205static inline void xfrm4_net_sysctl_exit(struct net *net)
206{
207}
208#endif
209
210static int __net_init xfrm4_net_init(struct net *net)
211{
212 int ret;
213
214 memcpy(&net->xfrm.xfrm4_dst_ops, &xfrm4_dst_ops_template,
215 sizeof(xfrm4_dst_ops_template));
216 ret = dst_entries_init(dst: &net->xfrm.xfrm4_dst_ops);
217 if (ret)
218 return ret;
219
220 ret = xfrm4_net_sysctl_init(net);
221 if (ret)
222 dst_entries_destroy(dst: &net->xfrm.xfrm4_dst_ops);
223
224 return ret;
225}
226
227static void __net_exit xfrm4_net_exit(struct net *net)
228{
229 xfrm4_net_sysctl_exit(net);
230 dst_entries_destroy(dst: &net->xfrm.xfrm4_dst_ops);
231}
232
233static struct pernet_operations __net_initdata xfrm4_net_ops = {
234 .init = xfrm4_net_init,
235 .exit = xfrm4_net_exit,
236};
237
238static void __init xfrm4_policy_init(void)
239{
240 xfrm_policy_register_afinfo(afinfo: &xfrm4_policy_afinfo, AF_INET);
241}
242
243void __init xfrm4_init(void)
244{
245 xfrm4_state_init();
246 xfrm4_policy_init();
247 xfrm4_protocol_init();
248 register_pernet_subsys(&xfrm4_net_ops);
249}
250

source code of linux/net/ipv4/xfrm4_policy.c