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_skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
53 
54 	ovs_vport_receive(vport, skb, NULL);
55 	return;
56 
57 error:
58 	kfree_skb(skb);
59 }
60 
61 /* Called with rcu_read_lock and bottom-halves disabled. */
62 static rx_handler_result_t netdev_frame_hook(struct sk_buff **pskb)
63 {
64 	struct sk_buff *skb = *pskb;
65 	struct vport *vport;
66 
67 	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
68 		return RX_HANDLER_PASS;
69 
70 	vport = ovs_netdev_get_vport(skb->dev);
71 
72 	netdev_port_receive(vport, skb);
73 
74 	return RX_HANDLER_CONSUMED;
75 }
76 
77 static struct vport *netdev_create(const struct vport_parms *parms)
78 {
79 	struct vport *vport;
80 	struct netdev_vport *netdev_vport;
81 	int err;
82 
83 	vport = ovs_vport_alloc(sizeof(struct netdev_vport),
84 				&ovs_netdev_vport_ops, parms);
85 	if (IS_ERR(vport)) {
86 		err = PTR_ERR(vport);
87 		goto error;
88 	}
89 
90 	netdev_vport = netdev_vport_priv(vport);
91 
92 	netdev_vport->dev = dev_get_by_name(ovs_dp_get_net(vport->dp), parms->name);
93 	if (!netdev_vport->dev) {
94 		err = -ENODEV;
95 		goto error_free_vport;
96 	}
97 
98 	if (netdev_vport->dev->flags & IFF_LOOPBACK ||
99 	    netdev_vport->dev->type != ARPHRD_ETHER ||
100 	    ovs_is_internal_dev(netdev_vport->dev)) {
101 		err = -EINVAL;
102 		goto error_put;
103 	}
104 
105 	rtnl_lock();
106 	err = netdev_rx_handler_register(netdev_vport->dev, netdev_frame_hook,
107 					 vport);
108 	if (err)
109 		goto error_unlock;
110 
111 	dev_set_promiscuity(netdev_vport->dev, 1);
112 	netdev_vport->dev->priv_flags |= IFF_OVS_DATAPATH;
113 	rtnl_unlock();
114 
115 	return vport;
116 
117 error_unlock:
118 	rtnl_unlock();
119 error_put:
120 	dev_put(netdev_vport->dev);
121 error_free_vport:
122 	ovs_vport_free(vport);
123 error:
124 	return ERR_PTR(err);
125 }
126 
127 static void free_port_rcu(struct rcu_head *rcu)
128 {
129 	struct netdev_vport *netdev_vport = container_of(rcu,
130 					struct netdev_vport, rcu);
131 
132 	dev_put(netdev_vport->dev);
133 	ovs_vport_free(vport_from_priv(netdev_vport));
134 }
135 
136 static void netdev_destroy(struct vport *vport)
137 {
138 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
139 
140 	rtnl_lock();
141 	netdev_vport->dev->priv_flags &= ~IFF_OVS_DATAPATH;
142 	netdev_rx_handler_unregister(netdev_vport->dev);
143 	dev_set_promiscuity(netdev_vport->dev, -1);
144 	rtnl_unlock();
145 
146 	call_rcu(&netdev_vport->rcu, free_port_rcu);
147 }
148 
149 const char *ovs_netdev_get_name(const struct vport *vport)
150 {
151 	const struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
152 	return netdev_vport->dev->name;
153 }
154 
155 static unsigned int packet_length(const struct sk_buff *skb)
156 {
157 	unsigned int length = skb->len - ETH_HLEN;
158 
159 	if (skb->protocol == htons(ETH_P_8021Q))
160 		length -= VLAN_HLEN;
161 
162 	return length;
163 }
164 
165 static int netdev_send(struct vport *vport, struct sk_buff *skb)
166 {
167 	struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
168 	int mtu = netdev_vport->dev->mtu;
169 	int len;
170 
171 	if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
172 		net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
173 				     netdev_vport->dev->name,
174 				     packet_length(skb), mtu);
175 		goto drop;
176 	}
177 
178 	skb->dev = netdev_vport->dev;
179 	len = skb->len;
180 	dev_queue_xmit(skb);
181 
182 	return len;
183 
184 drop:
185 	kfree_skb(skb);
186 	return 0;
187 }
188 
189 /* Returns null if this device is not attached to a datapath. */
190 struct vport *ovs_netdev_get_vport(struct net_device *dev)
191 {
192 	if (likely(dev->priv_flags & IFF_OVS_DATAPATH))
193 		return (struct vport *)
194 			rcu_dereference_rtnl(dev->rx_handler_data);
195 	else
196 		return NULL;
197 }
198 
199 const struct vport_ops ovs_netdev_vport_ops = {
200 	.type		= OVS_VPORT_TYPE_NETDEV,
201 	.create		= netdev_create,
202 	.destroy	= netdev_destroy,
203 	.get_name	= ovs_netdev_get_name,
204 	.send		= netdev_send,
205 };
206