1 /*
2  * Copyright (c) 2007-2012 Nicira, Inc.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of version 2 of the GNU General Public
6  * License as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public License
14  * along with this program; if not, write to the Free Software
15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
16  * 02110-1301, USA
17  */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #include <linux/if_arp.h>
22 #include <linux/if_bridge.h>
23 #include <linux/if_vlan.h>
24 #include <linux/kernel.h>
25 #include <linux/llc.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/skbuff.h>
28 #include <linux/openvswitch.h>
29 
30 #include <net/llc.h>
31 
32 #include "datapath.h"
33 #include "vport-internal_dev.h"
34 #include "vport-netdev.h"
35 
36 /* Must be called with rcu_read_lock. */
37 static void netdev_port_receive(struct vport *vport, struct sk_buff *skb)
38 {
39 	if (unlikely(!vport))
40 		goto error;
41 
42 	if (unlikely(skb_warn_if_lro(skb)))
43 		goto error;
44 
45 	/* Make our own copy of the packet.  Otherwise we will mangle the
46 	 * packet for anyone who came before us (e.g. tcpdump via AF_PACKET).
47 	 */
48 	skb = skb_share_check(skb, GFP_ATOMIC);
49 	if (unlikely(!skb))
50 		return;
51 
52 	skb_push(skb, ETH_HLEN);
53 	ovs_skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
54 
55 	ovs_vport_receive(vport, skb, NULL);
56 	return;
57 
58 error:
59 	kfree_skb(skb);
60 }
61 
62 /* Called with rcu_read_lock and bottom-halves disabled. */
63 static rx_handler_result_t netdev_frame_hook(struct sk_buff **pskb)
64 {
65 	struct sk_buff *skb = *pskb;
66 	struct vport *vport;
67 
68 	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
69 		return RX_HANDLER_PASS;
70 
71 	vport = ovs_netdev_get_vport(skb->dev);
72 
73 	netdev_port_receive(vport, skb);
74 
75 	return RX_HANDLER_CONSUMED;
76 }
77 
78 static struct net_device *get_dpdev(struct datapath *dp)
79 {
80 	struct vport *local;
81 
82 	local = ovs_vport_ovsl(dp, OVSP_LOCAL);
83 	BUG_ON(!local);
84 	return netdev_vport_priv(local)->dev;
85 }
86 
87 static struct vport *netdev_create(const struct vport_parms *parms)
88 {
89 	struct vport *vport;
90 	struct netdev_vport *netdev_vport;
91 	int err;
92 
93 	vport = ovs_vport_alloc(sizeof(struct netdev_vport),
94 				&ovs_netdev_vport_ops, parms);
95 	if (IS_ERR(vport)) {
96 		err = PTR_ERR(vport);
97 		goto error;
98 	}
99 
100 	netdev_vport = netdev_vport_priv(vport);
101 
102 	netdev_vport->dev = dev_get_by_name(ovs_dp_get_net(vport->dp), parms->name);
103 	if (!netdev_vport->dev) {
104 		err = -ENODEV;
105 		goto error_free_vport;
106 	}
107 
108 	if (netdev_vport->dev->flags & IFF_LOOPBACK ||
109 	    netdev_vport->dev->type != ARPHRD_ETHER ||
110 	    ovs_is_internal_dev(netdev_vport->dev)) {
111 		err = -EINVAL;
112 		goto error_put;
113 	}
114 
115 	rtnl_lock();
116 	err = netdev_master_upper_dev_link(netdev_vport->dev,
117 					   get_dpdev(vport->dp));
118 	if (err)
119 		goto error_unlock;
120 
121 	err = netdev_rx_handler_register(netdev_vport->dev, netdev_frame_hook,
122 					 vport);
123 	if (err)
124 		goto error_master_upper_dev_unlink;
125 
126 	dev_set_promiscuity(netdev_vport->dev, 1);
127 	netdev_vport->dev->priv_flags |= IFF_OVS_DATAPATH;
128 	rtnl_unlock();
129 
130 	return vport;
131 
132 error_master_upper_dev_unlink:
133 	netdev_upper_dev_unlink(netdev_vport->dev, get_dpdev(vport->dp));
134 error_unlock:
135 	rtnl_unlock();
136 error_put:
137 	dev_put(netdev_vport->dev);
138 error_free_vport:
139 	ovs_vport_free(vport);
140 error:
141 	return ERR_PTR(err);
142 }
143 
144 static void free_port_rcu(struct rcu_head *rcu)
145 {
146 	struct netdev_vport *netdev_vport = container_of(rcu,
147 					struct netdev_vport, rcu);
148 
149 	dev_put(netdev_vport->dev);
150 	ovs_vport_free(vport_from_priv(netdev_vport));
151 }
152 
153 static void netdev_destroy(struct vport *vport)
154 {
155 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
156 
157 	rtnl_lock();
158 	netdev_vport->dev->priv_flags &= ~IFF_OVS_DATAPATH;
159 	netdev_rx_handler_unregister(netdev_vport->dev);
160 	netdev_upper_dev_unlink(netdev_vport->dev, get_dpdev(vport->dp));
161 	dev_set_promiscuity(netdev_vport->dev, -1);
162 	rtnl_unlock();
163 
164 	call_rcu(&netdev_vport->rcu, free_port_rcu);
165 }
166 
167 const char *ovs_netdev_get_name(const struct vport *vport)
168 {
169 	const struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
170 	return netdev_vport->dev->name;
171 }
172 
173 static unsigned int packet_length(const struct sk_buff *skb)
174 {
175 	unsigned int length = skb->len - ETH_HLEN;
176 
177 	if (skb->protocol == htons(ETH_P_8021Q))
178 		length -= VLAN_HLEN;
179 
180 	return length;
181 }
182 
183 static int netdev_send(struct vport *vport, struct sk_buff *skb)
184 {
185 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
186 	int mtu = netdev_vport->dev->mtu;
187 	int len;
188 
189 	if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
190 		net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
191 				     netdev_vport->dev->name,
192 				     packet_length(skb), mtu);
193 		goto drop;
194 	}
195 
196 	skb->dev = netdev_vport->dev;
197 	len = skb->len;
198 	dev_queue_xmit(skb);
199 
200 	return len;
201 
202 drop:
203 	kfree_skb(skb);
204 	return 0;
205 }
206 
207 /* Returns null if this device is not attached to a datapath. */
208 struct vport *ovs_netdev_get_vport(struct net_device *dev)
209 {
210 	if (likely(dev->priv_flags & IFF_OVS_DATAPATH))
211 		return (struct vport *)
212 			rcu_dereference_rtnl(dev->rx_handler_data);
213 	else
214 		return NULL;
215 }
216 
217 const struct vport_ops ovs_netdev_vport_ops = {
218 	.type		= OVS_VPORT_TYPE_NETDEV,
219 	.create		= netdev_create,
220 	.destroy	= netdev_destroy,
221 	.get_name	= ovs_netdev_get_name,
222 	.send		= netdev_send,
223 };
224