1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *	Vxlan multicast group handling
4 *
5 */
6#include <linux/kernel.h>
7#include <net/net_namespace.h>
8#include <net/sock.h>
9#include <linux/igmp.h>
10#include <net/vxlan.h>
11
12#include "vxlan_private.h"
13
14/* Update multicast group membership when first VNI on
15 * multicast address is brought up
16 */
17int vxlan_igmp_join(struct vxlan_dev *vxlan, union vxlan_addr *rip,
18		    int rifindex)
19{
20	union vxlan_addr *ip = (rip ? : &vxlan->default_dst.remote_ip);
21	int ifindex = (rifindex ? : vxlan->default_dst.remote_ifindex);
22	int ret = -EINVAL;
23	struct sock *sk;
24
25	if (ip->sa.sa_family == AF_INET) {
26		struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
27		struct ip_mreqn mreq = {
28			.imr_multiaddr.s_addr	= ip->sin.sin_addr.s_addr,
29			.imr_ifindex		= ifindex,
30		};
31
32		sk = sock4->sock->sk;
33		lock_sock(sk);
34		ret = ip_mc_join_group(sk, &mreq);
35		release_sock(sk);
36#if IS_ENABLED(CONFIG_IPV6)
37	} else {
38		struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
39
40		sk = sock6->sock->sk;
41		lock_sock(sk);
42		ret = ipv6_stub->ipv6_sock_mc_join(sk, ifindex,
43						   &ip->sin6.sin6_addr);
44		release_sock(sk);
45#endif
46	}
47
48	return ret;
49}
50
51int vxlan_igmp_leave(struct vxlan_dev *vxlan, union vxlan_addr *rip,
52		     int rifindex)
53{
54	union vxlan_addr *ip = (rip ? : &vxlan->default_dst.remote_ip);
55	int ifindex = (rifindex ? : vxlan->default_dst.remote_ifindex);
56	int ret = -EINVAL;
57	struct sock *sk;
58
59	if (ip->sa.sa_family == AF_INET) {
60		struct vxlan_sock *sock4 = rtnl_dereference(vxlan->vn4_sock);
61		struct ip_mreqn mreq = {
62			.imr_multiaddr.s_addr	= ip->sin.sin_addr.s_addr,
63			.imr_ifindex		= ifindex,
64		};
65
66		sk = sock4->sock->sk;
67		lock_sock(sk);
68		ret = ip_mc_leave_group(sk, &mreq);
69		release_sock(sk);
70#if IS_ENABLED(CONFIG_IPV6)
71	} else {
72		struct vxlan_sock *sock6 = rtnl_dereference(vxlan->vn6_sock);
73
74		sk = sock6->sock->sk;
75		lock_sock(sk);
76		ret = ipv6_stub->ipv6_sock_mc_drop(sk, ifindex,
77						   &ip->sin6.sin6_addr);
78		release_sock(sk);
79#endif
80	}
81
82	return ret;
83}
84
85static bool vxlan_group_used_match(union vxlan_addr *ip, int ifindex,
86				   union vxlan_addr *rip, int rifindex)
87{
88	if (!vxlan_addr_multicast(rip))
89		return false;
90
91	if (!vxlan_addr_equal(rip, ip))
92		return false;
93
94	if (rifindex != ifindex)
95		return false;
96
97	return true;
98}
99
100static bool vxlan_group_used_by_vnifilter(struct vxlan_dev *vxlan,
101					  union vxlan_addr *ip, int ifindex)
102{
103	struct vxlan_vni_group *vg = rtnl_dereference(vxlan->vnigrp);
104	struct vxlan_vni_node *v, *tmp;
105
106	if (vxlan_group_used_match(ip, ifindex,
107				   &vxlan->default_dst.remote_ip,
108				   vxlan->default_dst.remote_ifindex))
109		return true;
110
111	list_for_each_entry_safe(v, tmp, &vg->vni_list, vlist) {
112		if (!vxlan_addr_multicast(&v->remote_ip))
113			continue;
114
115		if (vxlan_group_used_match(ip, ifindex,
116					   &v->remote_ip,
117					   vxlan->default_dst.remote_ifindex))
118			return true;
119	}
120
121	return false;
122}
123
124/* See if multicast group is already in use by other ID */
125bool vxlan_group_used(struct vxlan_net *vn, struct vxlan_dev *dev,
126		      __be32 vni, union vxlan_addr *rip, int rifindex)
127{
128	union vxlan_addr *ip = (rip ? : &dev->default_dst.remote_ip);
129	int ifindex = (rifindex ? : dev->default_dst.remote_ifindex);
130	struct vxlan_dev *vxlan;
131	struct vxlan_sock *sock4;
132#if IS_ENABLED(CONFIG_IPV6)
133	struct vxlan_sock *sock6;
134#endif
135	unsigned short family = dev->default_dst.remote_ip.sa.sa_family;
136
137	sock4 = rtnl_dereference(dev->vn4_sock);
138
139	/* The vxlan_sock is only used by dev, leaving group has
140	 * no effect on other vxlan devices.
141	 */
142	if (family == AF_INET && sock4 && refcount_read(&sock4->refcnt) == 1)
143		return false;
144
145#if IS_ENABLED(CONFIG_IPV6)
146	sock6 = rtnl_dereference(dev->vn6_sock);
147	if (family == AF_INET6 && sock6 && refcount_read(&sock6->refcnt) == 1)
148		return false;
149#endif
150
151	list_for_each_entry(vxlan, &vn->vxlan_list, next) {
152		if (!netif_running(vxlan->dev) || vxlan == dev)
153			continue;
154
155		if (family == AF_INET &&
156		    rtnl_dereference(vxlan->vn4_sock) != sock4)
157			continue;
158#if IS_ENABLED(CONFIG_IPV6)
159		if (family == AF_INET6 &&
160		    rtnl_dereference(vxlan->vn6_sock) != sock6)
161			continue;
162#endif
163		if (vxlan->cfg.flags & VXLAN_F_VNIFILTER) {
164			if (!vxlan_group_used_by_vnifilter(vxlan, ip, ifindex))
165				continue;
166		} else {
167			if (!vxlan_group_used_match(ip, ifindex,
168						    &vxlan->default_dst.remote_ip,
169						    vxlan->default_dst.remote_ifindex))
170				continue;
171		}
172
173		return true;
174	}
175
176	return false;
177}
178
179static int vxlan_multicast_join_vnigrp(struct vxlan_dev *vxlan)
180{
181	struct vxlan_vni_group *vg = rtnl_dereference(vxlan->vnigrp);
182	struct vxlan_vni_node *v, *tmp, *vgood = NULL;
183	int ret = 0;
184
185	list_for_each_entry_safe(v, tmp, &vg->vni_list, vlist) {
186		if (!vxlan_addr_multicast(&v->remote_ip))
187			continue;
188		/* skip if address is same as default address */
189		if (vxlan_addr_equal(&v->remote_ip,
190				     &vxlan->default_dst.remote_ip))
191			continue;
192		ret = vxlan_igmp_join(vxlan, &v->remote_ip, 0);
193		if (ret == -EADDRINUSE)
194			ret = 0;
195		if (ret)
196			goto out;
197		vgood = v;
198	}
199out:
200	if (ret) {
201		list_for_each_entry_safe(v, tmp, &vg->vni_list, vlist) {
202			if (!vxlan_addr_multicast(&v->remote_ip))
203				continue;
204			if (vxlan_addr_equal(&v->remote_ip,
205					     &vxlan->default_dst.remote_ip))
206				continue;
207			vxlan_igmp_leave(vxlan, &v->remote_ip, 0);
208			if (v == vgood)
209				break;
210		}
211	}
212
213	return ret;
214}
215
216static int vxlan_multicast_leave_vnigrp(struct vxlan_dev *vxlan)
217{
218	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
219	struct vxlan_vni_group *vg = rtnl_dereference(vxlan->vnigrp);
220	struct vxlan_vni_node *v, *tmp;
221	int last_err = 0, ret;
222
223	list_for_each_entry_safe(v, tmp, &vg->vni_list, vlist) {
224		if (vxlan_addr_multicast(&v->remote_ip) &&
225		    !vxlan_group_used(vn, vxlan, v->vni, &v->remote_ip,
226				      0)) {
227			ret = vxlan_igmp_leave(vxlan, &v->remote_ip, 0);
228			if (ret)
229				last_err = ret;
230		}
231	}
232
233	return last_err;
234}
235
236int vxlan_multicast_join(struct vxlan_dev *vxlan)
237{
238	int ret = 0;
239
240	if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip)) {
241		ret = vxlan_igmp_join(vxlan, &vxlan->default_dst.remote_ip,
242				      vxlan->default_dst.remote_ifindex);
243		if (ret == -EADDRINUSE)
244			ret = 0;
245		if (ret)
246			return ret;
247	}
248
249	if (vxlan->cfg.flags & VXLAN_F_VNIFILTER)
250		return vxlan_multicast_join_vnigrp(vxlan);
251
252	return 0;
253}
254
255int vxlan_multicast_leave(struct vxlan_dev *vxlan)
256{
257	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
258	int ret = 0;
259
260	if (vxlan_addr_multicast(&vxlan->default_dst.remote_ip) &&
261	    !vxlan_group_used(vn, vxlan, 0, NULL, 0)) {
262		ret = vxlan_igmp_leave(vxlan, &vxlan->default_dst.remote_ip,
263				       vxlan->default_dst.remote_ifindex);
264		if (ret)
265			return ret;
266	}
267
268	if (vxlan->cfg.flags & VXLAN_F_VNIFILTER)
269		return vxlan_multicast_leave_vnigrp(vxlan);
270
271	return 0;
272}
273