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1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright 2011-2014 Autronica Fire and Security AS
3  *
4  * Author(s):
5  *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
6  *
7  * Frame handler other utility functions for HSR and PRP.
8  */
9 
10 #include "hsr_slave.h"
11 #include <linux/etherdevice.h>
12 #include <linux/if_arp.h>
13 #include <linux/if_vlan.h>
14 #include "hsr_main.h"
15 #include "hsr_device.h"
16 #include "hsr_forward.h"
17 #include "hsr_framereg.h"
18 
hsr_invalid_dan_ingress_frame(__be16 protocol)19 bool hsr_invalid_dan_ingress_frame(__be16 protocol)
20 {
21 	return (protocol != htons(ETH_P_PRP) && protocol != htons(ETH_P_HSR));
22 }
23 
hsr_handle_frame(struct sk_buff ** pskb)24 static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb)
25 {
26 	struct sk_buff *skb = *pskb;
27 	struct hsr_port *port;
28 	struct hsr_priv *hsr;
29 	__be16 protocol;
30 
31 	/* Packets from dev_loopback_xmit() do not have L2 header, bail out */
32 	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
33 		return RX_HANDLER_PASS;
34 
35 	if (!skb_mac_header_was_set(skb)) {
36 		WARN_ONCE(1, "%s: skb invalid", __func__);
37 		return RX_HANDLER_PASS;
38 	}
39 
40 	port = hsr_port_get_rcu(skb->dev);
41 	if (!port)
42 		goto finish_pass;
43 	hsr = port->hsr;
44 
45 	if (hsr_addr_is_self(port->hsr, eth_hdr(skb)->h_source)) {
46 		/* Directly kill frames sent by ourselves */
47 		kfree_skb(skb);
48 		goto finish_consume;
49 	}
50 
51 	/* For HSR, only tagged frames are expected (unless the device offloads
52 	 * HSR tag removal), but for PRP there could be non tagged frames as
53 	 * well from Single attached nodes (SANs).
54 	 */
55 	protocol = eth_hdr(skb)->h_proto;
56 
57 	if (!(port->dev->features & NETIF_F_HW_HSR_TAG_RM) &&
58 	    hsr->proto_ops->invalid_dan_ingress_frame &&
59 	    hsr->proto_ops->invalid_dan_ingress_frame(protocol))
60 		goto finish_pass;
61 
62 	skb_push(skb, ETH_HLEN);
63 	skb_reset_mac_header(skb);
64 	if ((!hsr->prot_version && protocol == htons(ETH_P_PRP)) ||
65 	    protocol == htons(ETH_P_HSR))
66 		skb_set_network_header(skb, ETH_HLEN + HSR_HLEN);
67 	skb_reset_mac_len(skb);
68 
69 	hsr_forward_skb(skb, port);
70 
71 finish_consume:
72 	return RX_HANDLER_CONSUMED;
73 
74 finish_pass:
75 	return RX_HANDLER_PASS;
76 }
77 
hsr_port_exists(const struct net_device * dev)78 bool hsr_port_exists(const struct net_device *dev)
79 {
80 	return rcu_access_pointer(dev->rx_handler) == hsr_handle_frame;
81 }
82 
hsr_check_dev_ok(struct net_device * dev,struct netlink_ext_ack * extack)83 static int hsr_check_dev_ok(struct net_device *dev,
84 			    struct netlink_ext_ack *extack)
85 {
86 	/* Don't allow HSR on non-ethernet like devices */
87 	if ((dev->flags & IFF_LOOPBACK) || dev->type != ARPHRD_ETHER ||
88 	    dev->addr_len != ETH_ALEN) {
89 		NL_SET_ERR_MSG_MOD(extack, "Cannot use loopback or non-ethernet device as HSR slave.");
90 		return -EINVAL;
91 	}
92 
93 	/* Don't allow enslaving hsr devices */
94 	if (is_hsr_master(dev)) {
95 		NL_SET_ERR_MSG_MOD(extack,
96 				   "Cannot create trees of HSR devices.");
97 		return -EINVAL;
98 	}
99 
100 	if (hsr_port_exists(dev)) {
101 		NL_SET_ERR_MSG_MOD(extack,
102 				   "This device is already a HSR slave.");
103 		return -EINVAL;
104 	}
105 
106 	if (is_vlan_dev(dev)) {
107 		NL_SET_ERR_MSG_MOD(extack, "HSR on top of VLAN is not yet supported in this driver.");
108 		return -EINVAL;
109 	}
110 
111 	if (dev->priv_flags & IFF_DONT_BRIDGE) {
112 		NL_SET_ERR_MSG_MOD(extack,
113 				   "This device does not support bridging.");
114 		return -EOPNOTSUPP;
115 	}
116 
117 	/* HSR over bonded devices has not been tested, but I'm not sure it
118 	 * won't work...
119 	 */
120 
121 	return 0;
122 }
123 
124 /* Setup device to be added to the HSR bridge. */
hsr_portdev_setup(struct hsr_priv * hsr,struct net_device * dev,struct hsr_port * port,struct netlink_ext_ack * extack)125 static int hsr_portdev_setup(struct hsr_priv *hsr, struct net_device *dev,
126 			     struct hsr_port *port,
127 			     struct netlink_ext_ack *extack)
128 
129 {
130 	struct net_device *hsr_dev;
131 	struct hsr_port *master;
132 	int res;
133 
134 	/* Don't use promiscuous mode for offload since L2 frame forward
135 	 * happens at the offloaded hardware.
136 	 */
137 	if (!port->hsr->fwd_offloaded) {
138 		res = dev_set_promiscuity(dev, 1);
139 		if (res)
140 			return res;
141 	}
142 
143 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
144 	hsr_dev = master->dev;
145 
146 	res = netdev_upper_dev_link(dev, hsr_dev, extack);
147 	if (res)
148 		goto fail_upper_dev_link;
149 
150 	res = netdev_rx_handler_register(dev, hsr_handle_frame, port);
151 	if (res)
152 		goto fail_rx_handler;
153 	dev_disable_lro(dev);
154 
155 	return 0;
156 
157 fail_rx_handler:
158 	netdev_upper_dev_unlink(dev, hsr_dev);
159 fail_upper_dev_link:
160 	if (!port->hsr->fwd_offloaded)
161 		dev_set_promiscuity(dev, -1);
162 
163 	return res;
164 }
165 
hsr_add_port(struct hsr_priv * hsr,struct net_device * dev,enum hsr_port_type type,struct netlink_ext_ack * extack)166 int hsr_add_port(struct hsr_priv *hsr, struct net_device *dev,
167 		 enum hsr_port_type type, struct netlink_ext_ack *extack)
168 {
169 	struct hsr_port *port, *master;
170 	int res;
171 
172 	if (type != HSR_PT_MASTER) {
173 		res = hsr_check_dev_ok(dev, extack);
174 		if (res)
175 			return res;
176 	}
177 
178 	port = hsr_port_get_hsr(hsr, type);
179 	if (port)
180 		return -EBUSY;	/* This port already exists */
181 
182 	port = kzalloc(sizeof(*port), GFP_KERNEL);
183 	if (!port)
184 		return -ENOMEM;
185 
186 	port->hsr = hsr;
187 	port->dev = dev;
188 	port->type = type;
189 
190 	if (type != HSR_PT_MASTER) {
191 		res = hsr_portdev_setup(hsr, dev, port, extack);
192 		if (res)
193 			goto fail_dev_setup;
194 	}
195 
196 	list_add_tail_rcu(&port->port_list, &hsr->ports);
197 	synchronize_rcu();
198 
199 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
200 	netdev_update_features(master->dev);
201 	dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
202 
203 	return 0;
204 
205 fail_dev_setup:
206 	kfree(port);
207 	return res;
208 }
209 
hsr_del_port(struct hsr_port * port)210 void hsr_del_port(struct hsr_port *port)
211 {
212 	struct hsr_priv *hsr;
213 	struct hsr_port *master;
214 
215 	hsr = port->hsr;
216 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
217 	list_del_rcu(&port->port_list);
218 
219 	if (port != master) {
220 		netdev_update_features(master->dev);
221 		dev_set_mtu(master->dev, hsr_get_max_mtu(hsr));
222 		netdev_rx_handler_unregister(port->dev);
223 		if (!port->hsr->fwd_offloaded)
224 			dev_set_promiscuity(port->dev, -1);
225 		netdev_upper_dev_unlink(port->dev, master->dev);
226 	}
227 
228 	synchronize_rcu();
229 
230 	kfree(port);
231 }
232