1 /*
2 * Copyright (c) 2015 Intel Corporation
3 * Copyright (c) 2017 Linaro Limited
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 /**
9 * @file
10 *
11 * Network loopback interface implementation.
12 */
13
14 #define LOG_MODULE_NAME netlo
15 #define LOG_LEVEL CONFIG_NET_LOOPBACK_LOG_LEVEL
16
17 #include <zephyr/logging/log.h>
18 LOG_MODULE_REGISTER(LOG_MODULE_NAME);
19
20 #include <zephyr/net/net_pkt.h>
21 #include <zephyr/net_buf.h>
22 #include <zephyr/net/net_ip.h>
23 #include <zephyr/net/net_if.h>
24 #include <zephyr/net/loopback.h>
25
26 #include <zephyr/net/dummy.h>
27
28 /* Allow network tests to control the IP addresses swapping */
29 #if defined(CONFIG_NET_TEST)
30 static bool loopback_dont_swap_addresses;
31
loopback_enable_address_swap(bool swap_addresses)32 void loopback_enable_address_swap(bool swap_addresses)
33 {
34 loopback_dont_swap_addresses = !swap_addresses;
35 }
36 #endif /* CONFIG_NET_TEST */
37
loopback_dev_init(const struct device * dev)38 int loopback_dev_init(const struct device *dev)
39 {
40 ARG_UNUSED(dev);
41
42 return 0;
43 }
44
loopback_init(struct net_if * iface)45 static void loopback_init(struct net_if *iface)
46 {
47 struct net_if_addr *ifaddr;
48
49 /* RFC 7042, s.2.1.1. address to use in documentation */
50 net_if_set_link_addr(iface, "\x00\x00\x5e\x00\x53\xff", 6,
51 NET_LINK_DUMMY);
52
53 if (IS_ENABLED(CONFIG_NET_IPV4)) {
54 struct net_in_addr ipv4_loopback = NET_INADDR_LOOPBACK_INIT;
55 struct net_in_addr netmask = { { { 255, 0, 0, 0 } } };
56
57 ifaddr = net_if_ipv4_addr_add(iface, &ipv4_loopback,
58 NET_ADDR_AUTOCONF, 0);
59 if (!ifaddr) {
60 LOG_ERR("Failed to register IPv4 loopback address");
61 }
62
63 net_if_ipv4_set_netmask_by_addr(iface, &ipv4_loopback, &netmask);
64 }
65
66 if (IS_ENABLED(CONFIG_NET_IPV6)) {
67 struct net_in6_addr ipv6_loopback = NET_IN6ADDR_LOOPBACK_INIT;
68
69 ifaddr = net_if_ipv6_addr_add(iface, &ipv6_loopback,
70 NET_ADDR_AUTOCONF, 0);
71 if (!ifaddr) {
72 LOG_ERR("Failed to register IPv6 loopback address");
73 }
74 }
75
76 if (IS_ENABLED(CONFIG_NET_INTERFACE_NAME)) {
77 int ret;
78
79 ret = net_if_set_name(iface, "lo");
80 if (ret < 0) {
81 LOG_ERR("Failed to set loopback interface name (%d)", ret);
82 }
83 }
84 }
85
86 #ifdef CONFIG_NET_LOOPBACK_SIMULATE_PACKET_DROP
87 static float loopback_packet_drop_ratio = 0.0f;
88 static float loopback_packet_drop_state = 0.0f;
89 static int loopback_packet_dropped_count;
90
loopback_set_packet_drop_ratio(float ratio)91 int loopback_set_packet_drop_ratio(float ratio)
92 {
93 if (ratio < 0.0f || ratio > 1.0f) {
94 return -EINVAL;
95 }
96 loopback_packet_drop_ratio = ratio;
97 return 0;
98 }
99
loopback_get_num_dropped_packets(void)100 int loopback_get_num_dropped_packets(void)
101 {
102 return loopback_packet_dropped_count;
103 }
104
105 #endif
106
loopback_send(const struct device * dev,struct net_pkt * pkt)107 static int loopback_send(const struct device *dev, struct net_pkt *pkt)
108 {
109 struct net_pkt *cloned;
110 int res;
111
112 ARG_UNUSED(dev);
113
114 #ifdef CONFIG_NET_LOOPBACK_SIMULATE_PACKET_DROP
115 /* Drop packets based on the loopback_packet_drop_ratio
116 * a ratio of 0.2 will drop one every 5 packets
117 */
118 loopback_packet_drop_state += loopback_packet_drop_ratio;
119 if (loopback_packet_drop_state >= 1.0f) {
120 /* Administrate we dropped a packet */
121 loopback_packet_drop_state -= 1.0f;
122 loopback_packet_dropped_count++;
123 return 0;
124 }
125 #endif
126
127 if (!pkt->frags) {
128 LOG_ERR("No data to send");
129 return -ENODATA;
130 }
131
132 /* We should simulate normal driver meaning that if the packet is
133 * properly sent (which is always in this driver), then the packet
134 * must be dropped. This is very much needed for TCP packets where
135 * the packet is reference counted in various stages of sending.
136 */
137 cloned = net_pkt_rx_clone(pkt, K_MSEC(100));
138 if (!cloned) {
139 res = -ENOMEM;
140 goto out;
141 }
142
143 /* We need to swap the IP addresses because otherwise
144 * the packet will be dropped.
145 *
146 * Some of the network tests require that addresses are not swapped so allow
147 * the test to control this remotely.
148 */
149 if (!COND_CODE_1(CONFIG_NET_TEST, (loopback_dont_swap_addresses), (false))) {
150 if (net_pkt_family(pkt) == NET_AF_INET6) {
151 net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->src,
152 NET_IPV6_HDR(pkt)->dst);
153 net_ipv6_addr_copy_raw(NET_IPV6_HDR(cloned)->dst,
154 NET_IPV6_HDR(pkt)->src);
155 } else {
156 net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->src,
157 NET_IPV4_HDR(pkt)->dst);
158 net_ipv4_addr_copy_raw(NET_IPV4_HDR(cloned)->dst,
159 NET_IPV4_HDR(pkt)->src);
160 }
161 }
162
163 res = net_recv_data(net_pkt_iface(cloned), cloned);
164 if (res < 0) {
165 LOG_ERR("Data receive failed.");
166 }
167
168 out:
169 /* Let the receiving thread run now */
170 k_yield();
171
172 return res;
173 }
174
175 static struct dummy_api loopback_api = {
176 .iface_api.init = loopback_init,
177
178 .send = loopback_send,
179 };
180
181 NET_DEVICE_INIT(loopback, "lo",
182 loopback_dev_init, NULL, NULL, NULL,
183 CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
184 &loopback_api, DUMMY_L2,
185 NET_L2_GET_CTX_TYPE(DUMMY_L2), CONFIG_NET_LOOPBACK_MTU);
186
