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 
29 #include <net/llc.h>
30 
31 #include "datapath.h"
32 #include "vport-internal_dev.h"
33 #include "vport-netdev.h"
34 
35 /* Must be called with rcu_read_lock. */
36 static void netdev_port_receive(struct vport *vport, struct sk_buff *skb)
37 {
38 	if (unlikely(!vport))
39 		goto error;
40 
41 	if (unlikely(skb_warn_if_lro(skb)))
42 		goto error;
43 
44 	/* Make our own copy of the packet.  Otherwise we will mangle the
45 	 * packet for anyone who came before us (e.g. tcpdump via AF_PACKET).
46 	 */
47 	skb = skb_share_check(skb, GFP_ATOMIC);
48 	if (unlikely(!skb))
49 		return;
50 
51 	skb_push(skb, ETH_HLEN);
52 	ovs_vport_receive(vport, skb);
53 	return;
54 
55 error:
56 	kfree_skb(skb);
57 }
58 
59 /* Called with rcu_read_lock and bottom-halves disabled. */
60 static rx_handler_result_t netdev_frame_hook(struct sk_buff **pskb)
61 {
62 	struct sk_buff *skb = *pskb;
63 	struct vport *vport;
64 
65 	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
66 		return RX_HANDLER_PASS;
67 
68 	vport = ovs_netdev_get_vport(skb->dev);
69 
70 	netdev_port_receive(vport, skb);
71 
72 	return RX_HANDLER_CONSUMED;
73 }
74 
75 static struct vport *netdev_create(const struct vport_parms *parms)
76 {
77 	struct vport *vport;
78 	struct netdev_vport *netdev_vport;
79 	int err;
80 
81 	vport = ovs_vport_alloc(sizeof(struct netdev_vport),
82 				&ovs_netdev_vport_ops, parms);
83 	if (IS_ERR(vport)) {
84 		err = PTR_ERR(vport);
85 		goto error;
86 	}
87 
88 	netdev_vport = netdev_vport_priv(vport);
89 
90 	netdev_vport->dev = dev_get_by_name(ovs_dp_get_net(vport->dp), parms->name);
91 	if (!netdev_vport->dev) {
92 		err = -ENODEV;
93 		goto error_free_vport;
94 	}
95 
96 	if (netdev_vport->dev->flags & IFF_LOOPBACK ||
97 	    netdev_vport->dev->type != ARPHRD_ETHER ||
98 	    ovs_is_internal_dev(netdev_vport->dev)) {
99 		err = -EINVAL;
100 		goto error_put;
101 	}
102 
103 	rtnl_lock();
104 	err = netdev_rx_handler_register(netdev_vport->dev, netdev_frame_hook,
105 					 vport);
106 	if (err)
107 		goto error_unlock;
108 
109 	dev_set_promiscuity(netdev_vport->dev, 1);
110 	netdev_vport->dev->priv_flags |= IFF_OVS_DATAPATH;
111 	rtnl_unlock();
112 
113 	return vport;
114 
115 error_unlock:
116 	rtnl_unlock();
117 error_put:
118 	dev_put(netdev_vport->dev);
119 error_free_vport:
120 	ovs_vport_free(vport);
121 error:
122 	return ERR_PTR(err);
123 }
124 
125 static void free_port_rcu(struct rcu_head *rcu)
126 {
127 	struct netdev_vport *netdev_vport = container_of(rcu,
128 					struct netdev_vport, rcu);
129 
130 	dev_put(netdev_vport->dev);
131 	ovs_vport_free(vport_from_priv(netdev_vport));
132 }
133 
134 static void netdev_destroy(struct vport *vport)
135 {
136 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
137 
138 	rtnl_lock();
139 	netdev_vport->dev->priv_flags &= ~IFF_OVS_DATAPATH;
140 	netdev_rx_handler_unregister(netdev_vport->dev);
141 	dev_set_promiscuity(netdev_vport->dev, -1);
142 	rtnl_unlock();
143 
144 	call_rcu(&netdev_vport->rcu, free_port_rcu);
145 }
146 
147 const char *ovs_netdev_get_name(const struct vport *vport)
148 {
149 	const struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
150 	return netdev_vport->dev->name;
151 }
152 
153 static unsigned int packet_length(const struct sk_buff *skb)
154 {
155 	unsigned int length = skb->len - ETH_HLEN;
156 
157 	if (skb->protocol == htons(ETH_P_8021Q))
158 		length -= VLAN_HLEN;
159 
160 	return length;
161 }
162 
163 static int netdev_send(struct vport *vport, struct sk_buff *skb)
164 {
165 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
166 	int mtu = netdev_vport->dev->mtu;
167 	int len;
168 
169 	if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
170 		net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
171 				     netdev_vport->dev->name,
172 				     packet_length(skb), mtu);
173 		goto error;
174 	}
175 
176 	skb->dev = netdev_vport->dev;
177 	len = skb->len;
178 	dev_queue_xmit(skb);
179 
180 	return len;
181 
182 error:
183 	kfree_skb(skb);
184 	ovs_vport_record_error(vport, VPORT_E_TX_DROPPED);
185 	return 0;
186 }
187 
188 /* Returns null if this device is not attached to a datapath. */
189 struct vport *ovs_netdev_get_vport(struct net_device *dev)
190 {
191 	if (likely(dev->priv_flags & IFF_OVS_DATAPATH))
192 		return (struct vport *)
193 			rcu_dereference_rtnl(dev->rx_handler_data);
194 	else
195 		return NULL;
196 }
197 
198 const struct vport_ops ovs_netdev_vport_ops = {
199 	.type		= OVS_VPORT_TYPE_NETDEV,
200 	.create		= netdev_create,
201 	.destroy	= netdev_destroy,
202 	.get_name	= ovs_netdev_get_name,
203 	.send		= netdev_send,
204 };
205