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19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/if.h>
22#include <linux/skbuff.h>
23#include <linux/ip.h>
24#include <linux/if_tunnel.h>
25#include <linux/if_vlan.h>
26#include <linux/in.h>
27#include <linux/in_route.h>
28#include <linux/inetdevice.h>
29#include <linux/jhash.h>
30#include <linux/list.h>
31#include <linux/kernel.h>
32#include <linux/workqueue.h>
33#include <linux/rculist.h>
34#include <net/route.h>
35#include <net/xfrm.h>
36
37#include <net/icmp.h>
38#include <net/ip.h>
39#include <net/ip_tunnels.h>
40#include <net/gre.h>
41#include <net/net_namespace.h>
42#include <net/netns/generic.h>
43#include <net/protocol.h>
44
45#include "datapath.h"
46#include "vport.h"
47
48
49static __be32 be64_get_low32(__be64 x)
50{
51#ifdef __BIG_ENDIAN
52 return (__force __be32)x;
53#else
54 return (__force __be32)((__force u64)x >> 32);
55#endif
56}
57
58static __be16 filter_tnl_flags(__be16 flags)
59{
60 return flags & (TUNNEL_CSUM | TUNNEL_KEY);
61}
62
63static struct sk_buff *__build_header(struct sk_buff *skb,
64 int tunnel_hlen)
65{
66 const struct ovs_key_ipv4_tunnel *tun_key = OVS_CB(skb)->tun_key;
67 struct tnl_ptk_info tpi;
68
69 skb = gre_handle_offloads(skb, !!(tun_key->tun_flags & TUNNEL_CSUM));
70 if (IS_ERR(skb))
71 return NULL;
72
73 tpi.flags = filter_tnl_flags(tun_key->tun_flags);
74 tpi.proto = htons(ETH_P_TEB);
75 tpi.key = be64_get_low32(tun_key->tun_id);
76 tpi.seq = 0;
77 gre_build_header(skb, &tpi, tunnel_hlen);
78
79 return skb;
80}
81
82static __be64 key_to_tunnel_id(__be32 key, __be32 seq)
83{
84#ifdef __BIG_ENDIAN
85 return (__force __be64)((__force u64)seq << 32 | (__force u32)key);
86#else
87 return (__force __be64)((__force u64)key << 32 | (__force u32)seq);
88#endif
89}
90
91
92static int gre_rcv(struct sk_buff *skb,
93 const struct tnl_ptk_info *tpi)
94{
95 struct ovs_key_ipv4_tunnel tun_key;
96 struct ovs_net *ovs_net;
97 struct vport *vport;
98 __be64 key;
99
100 ovs_net = net_generic(dev_net(skb->dev), ovs_net_id);
101 vport = rcu_dereference(ovs_net->vport_net.gre_vport);
102 if (unlikely(!vport))
103 return PACKET_REJECT;
104
105 key = key_to_tunnel_id(tpi->key, tpi->seq);
106 ovs_flow_tun_key_init(&tun_key, ip_hdr(skb), key,
107 filter_tnl_flags(tpi->flags));
108
109 ovs_vport_receive(vport, skb, &tun_key);
110 return PACKET_RCVD;
111}
112
113static int gre_tnl_send(struct vport *vport, struct sk_buff *skb)
114{
115 struct net *net = ovs_dp_get_net(vport->dp);
116 struct flowi4 fl;
117 struct rtable *rt;
118 int min_headroom;
119 int tunnel_hlen;
120 __be16 df;
121 int err;
122
123 if (unlikely(!OVS_CB(skb)->tun_key)) {
124 err = -EINVAL;
125 goto error;
126 }
127
128
129 memset(&fl, 0, sizeof(fl));
130 fl.daddr = OVS_CB(skb)->tun_key->ipv4_dst;
131 fl.saddr = OVS_CB(skb)->tun_key->ipv4_src;
132 fl.flowi4_tos = RT_TOS(OVS_CB(skb)->tun_key->ipv4_tos);
133 fl.flowi4_mark = skb->mark;
134 fl.flowi4_proto = IPPROTO_GRE;
135
136 rt = ip_route_output_key(net, &fl);
137 if (IS_ERR(rt))
138 return PTR_ERR(rt);
139
140 tunnel_hlen = ip_gre_calc_hlen(OVS_CB(skb)->tun_key->tun_flags);
141
142 min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
143 + tunnel_hlen + sizeof(struct iphdr)
144 + (vlan_tx_tag_present(skb) ? VLAN_HLEN : 0);
145 if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
146 int head_delta = SKB_DATA_ALIGN(min_headroom -
147 skb_headroom(skb) +
148 16);
149 err = pskb_expand_head(skb, max_t(int, head_delta, 0),
150 0, GFP_ATOMIC);
151 if (unlikely(err))
152 goto err_free_rt;
153 }
154
155 if (vlan_tx_tag_present(skb)) {
156 if (unlikely(!__vlan_put_tag(skb,
157 skb->vlan_proto,
158 vlan_tx_tag_get(skb)))) {
159 err = -ENOMEM;
160 goto err_free_rt;
161 }
162 skb->vlan_tci = 0;
163 }
164
165
166 skb = __build_header(skb, tunnel_hlen);
167 if (unlikely(!skb)) {
168 err = 0;
169 goto err_free_rt;
170 }
171
172 df = OVS_CB(skb)->tun_key->tun_flags & TUNNEL_DONT_FRAGMENT ?
173 htons(IP_DF) : 0;
174
175 skb->local_df = 1;
176
177 return iptunnel_xmit(rt, skb, fl.saddr,
178 OVS_CB(skb)->tun_key->ipv4_dst, IPPROTO_GRE,
179 OVS_CB(skb)->tun_key->ipv4_tos,
180 OVS_CB(skb)->tun_key->ipv4_ttl, df, false);
181err_free_rt:
182 ip_rt_put(rt);
183error:
184 return err;
185}
186
187static struct gre_cisco_protocol gre_protocol = {
188 .handler = gre_rcv,
189 .priority = 1,
190};
191
192static int gre_ports;
193static int gre_init(void)
194{
195 int err;
196
197 gre_ports++;
198 if (gre_ports > 1)
199 return 0;
200
201 err = gre_cisco_register(&gre_protocol);
202 if (err)
203 pr_warn("cannot register gre protocol handler\n");
204
205 return err;
206}
207
208static void gre_exit(void)
209{
210 gre_ports--;
211 if (gre_ports > 0)
212 return;
213
214 gre_cisco_unregister(&gre_protocol);
215}
216
217static const char *gre_get_name(const struct vport *vport)
218{
219 return vport_priv(vport);
220}
221
222static struct vport *gre_create(const struct vport_parms *parms)
223{
224 struct net *net = ovs_dp_get_net(parms->dp);
225 struct ovs_net *ovs_net;
226 struct vport *vport;
227 int err;
228
229 err = gre_init();
230 if (err)
231 return ERR_PTR(err);
232
233 ovs_net = net_generic(net, ovs_net_id);
234 if (ovsl_dereference(ovs_net->vport_net.gre_vport)) {
235 vport = ERR_PTR(-EEXIST);
236 goto error;
237 }
238
239 vport = ovs_vport_alloc(IFNAMSIZ, &ovs_gre_vport_ops, parms);
240 if (IS_ERR(vport))
241 goto error;
242
243 strncpy(vport_priv(vport), parms->name, IFNAMSIZ);
244 rcu_assign_pointer(ovs_net->vport_net.gre_vport, vport);
245 return vport;
246
247error:
248 gre_exit();
249 return vport;
250}
251
252static void gre_tnl_destroy(struct vport *vport)
253{
254 struct net *net = ovs_dp_get_net(vport->dp);
255 struct ovs_net *ovs_net;
256
257 ovs_net = net_generic(net, ovs_net_id);
258
259 rcu_assign_pointer(ovs_net->vport_net.gre_vport, NULL);
260 ovs_vport_deferred_free(vport);
261 gre_exit();
262}
263
264const struct vport_ops ovs_gre_vport_ops = {
265 .type = OVS_VPORT_TYPE_GRE,
266 .create = gre_create,
267 .destroy = gre_tnl_destroy,
268 .get_name = gre_get_name,
269 .send = gre_tnl_send,
270};
271
