1 #include <linux/module.h>
2 #include <linux/kernel.h>
3 #include <linux/if_arp.h>
4 #include <net/rtnetlink.h>
5 #include <net/sock.h>
6 #include <net/af_vsock.h>
7 #include <uapi/linux/vsockmon.h>
8 #include <linux/virtio_vsock.h>
9
10 /* Virtio transport max packet size plus header */
11 #define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
12 sizeof(struct af_vsockmon_hdr))
13
14 struct pcpu_lstats {
15 u64 rx_packets;
16 u64 rx_bytes;
17 struct u64_stats_sync syncp;
18 };
19
vsockmon_dev_init(struct net_device * dev)20 static int vsockmon_dev_init(struct net_device *dev)
21 {
22 dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
23 if (!dev->lstats)
24 return -ENOMEM;
25 return 0;
26 }
27
vsockmon_dev_uninit(struct net_device * dev)28 static void vsockmon_dev_uninit(struct net_device *dev)
29 {
30 free_percpu(dev->lstats);
31 }
32
33 struct vsockmon {
34 struct vsock_tap vt;
35 };
36
vsockmon_open(struct net_device * dev)37 static int vsockmon_open(struct net_device *dev)
38 {
39 struct vsockmon *vsockmon = netdev_priv(dev);
40
41 vsockmon->vt.dev = dev;
42 vsockmon->vt.module = THIS_MODULE;
43 return vsock_add_tap(&vsockmon->vt);
44 }
45
vsockmon_close(struct net_device * dev)46 static int vsockmon_close(struct net_device *dev)
47 {
48 struct vsockmon *vsockmon = netdev_priv(dev);
49
50 return vsock_remove_tap(&vsockmon->vt);
51 }
52
vsockmon_xmit(struct sk_buff * skb,struct net_device * dev)53 static netdev_tx_t vsockmon_xmit(struct sk_buff *skb, struct net_device *dev)
54 {
55 int len = skb->len;
56 struct pcpu_lstats *stats = this_cpu_ptr(dev->lstats);
57
58 u64_stats_update_begin(&stats->syncp);
59 stats->rx_bytes += len;
60 stats->rx_packets++;
61 u64_stats_update_end(&stats->syncp);
62
63 dev_kfree_skb(skb);
64
65 return NETDEV_TX_OK;
66 }
67
68 static void
vsockmon_get_stats64(struct net_device * dev,struct rtnl_link_stats64 * stats)69 vsockmon_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
70 {
71 int i;
72 u64 bytes = 0, packets = 0;
73
74 for_each_possible_cpu(i) {
75 const struct pcpu_lstats *vstats;
76 u64 tbytes, tpackets;
77 unsigned int start;
78
79 vstats = per_cpu_ptr(dev->lstats, i);
80
81 do {
82 start = u64_stats_fetch_begin_irq(&vstats->syncp);
83 tbytes = vstats->rx_bytes;
84 tpackets = vstats->rx_packets;
85 } while (u64_stats_fetch_retry_irq(&vstats->syncp, start));
86
87 packets += tpackets;
88 bytes += tbytes;
89 }
90
91 stats->rx_packets = packets;
92 stats->tx_packets = 0;
93
94 stats->rx_bytes = bytes;
95 stats->tx_bytes = 0;
96 }
97
vsockmon_is_valid_mtu(int new_mtu)98 static int vsockmon_is_valid_mtu(int new_mtu)
99 {
100 return new_mtu >= (int)sizeof(struct af_vsockmon_hdr);
101 }
102
vsockmon_change_mtu(struct net_device * dev,int new_mtu)103 static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
104 {
105 if (!vsockmon_is_valid_mtu(new_mtu))
106 return -EINVAL;
107
108 dev->mtu = new_mtu;
109 return 0;
110 }
111
112 static const struct net_device_ops vsockmon_ops = {
113 .ndo_init = vsockmon_dev_init,
114 .ndo_uninit = vsockmon_dev_uninit,
115 .ndo_open = vsockmon_open,
116 .ndo_stop = vsockmon_close,
117 .ndo_start_xmit = vsockmon_xmit,
118 .ndo_get_stats64 = vsockmon_get_stats64,
119 .ndo_change_mtu = vsockmon_change_mtu,
120 };
121
always_on(struct net_device * dev)122 static u32 always_on(struct net_device *dev)
123 {
124 return 1;
125 }
126
127 static const struct ethtool_ops vsockmon_ethtool_ops = {
128 .get_link = always_on,
129 };
130
vsockmon_setup(struct net_device * dev)131 static void vsockmon_setup(struct net_device *dev)
132 {
133 dev->type = ARPHRD_VSOCKMON;
134 dev->priv_flags |= IFF_NO_QUEUE;
135
136 dev->netdev_ops = &vsockmon_ops;
137 dev->ethtool_ops = &vsockmon_ethtool_ops;
138 dev->needs_free_netdev = true;
139
140 dev->features = NETIF_F_SG | NETIF_F_FRAGLIST |
141 NETIF_F_HIGHDMA | NETIF_F_LLTX;
142
143 dev->flags = IFF_NOARP;
144
145 dev->mtu = DEFAULT_MTU;
146 }
147
148 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {
149 .kind = "vsockmon",
150 .priv_size = sizeof(struct vsockmon),
151 .setup = vsockmon_setup,
152 };
153
vsockmon_register(void)154 static __init int vsockmon_register(void)
155 {
156 return rtnl_link_register(&vsockmon_link_ops);
157 }
158
vsockmon_unregister(void)159 static __exit void vsockmon_unregister(void)
160 {
161 rtnl_link_unregister(&vsockmon_link_ops);
162 }
163
164 module_init(vsockmon_register);
165 module_exit(vsockmon_unregister);
166
167 MODULE_LICENSE("GPL v2");
168 MODULE_AUTHOR("Gerard Garcia <ggarcia@deic.uab.cat>");
169 MODULE_DESCRIPTION("Vsock monitoring device. Based on nlmon device.");
170 MODULE_ALIAS_RTNL_LINK("vsockmon");
171
