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
loopback_dev_init(const struct device * dev)28 int loopback_dev_init(const struct device *dev)
29 {
30 ARG_UNUSED(dev);
31
32 return 0;
33 }
34
loopback_init(struct net_if * iface)35 static void loopback_init(struct net_if *iface)
36 {
37 struct net_if_addr *ifaddr;
38
39 /* RFC 7042, s.2.1.1. address to use in documentation */
40 net_if_set_link_addr(iface, "\x00\x00\x5e\x00\x53\xff", 6,
41 NET_LINK_DUMMY);
42
43 if (IS_ENABLED(CONFIG_NET_IPV4)) {
44 struct in_addr ipv4_loopback = INADDR_LOOPBACK_INIT;
45
46 ifaddr = net_if_ipv4_addr_add(iface, &ipv4_loopback,
47 NET_ADDR_AUTOCONF, 0);
48 if (!ifaddr) {
49 LOG_ERR("Failed to register IPv4 loopback address");
50 }
51 }
52
53 if (IS_ENABLED(CONFIG_NET_IPV6)) {
54 struct in6_addr ipv6_loopback = IN6ADDR_LOOPBACK_INIT;
55
56 ifaddr = net_if_ipv6_addr_add(iface, &ipv6_loopback,
57 NET_ADDR_AUTOCONF, 0);
58 if (!ifaddr) {
59 LOG_ERR("Failed to register IPv6 loopback address");
60 }
61 }
62 }
63
64 #ifdef CONFIG_NET_LOOPBACK_SIMULATE_PACKET_DROP
65 static float loopback_packet_drop_ratio = 0.0f;
66 static float loopback_packet_drop_state = 0.0f;
67 static int loopback_packet_dropped_count;
68
loopback_set_packet_drop_ratio(float ratio)69 int loopback_set_packet_drop_ratio(float ratio)
70 {
71 if (ratio < 0.0f || ratio > 1.0f) {
72 return -EINVAL;
73 }
74 loopback_packet_drop_ratio = ratio;
75 return 0;
76 }
77
loopback_get_num_dropped_packets(void)78 int loopback_get_num_dropped_packets(void)
79 {
80 return loopback_packet_dropped_count;
81 }
82
83 #endif
84
loopback_send(const struct device * dev,struct net_pkt * pkt)85 static int loopback_send(const struct device *dev, struct net_pkt *pkt)
86 {
87 struct net_pkt *cloned;
88 int res;
89
90 ARG_UNUSED(dev);
91
92 #ifdef CONFIG_NET_LOOPBACK_SIMULATE_PACKET_DROP
93 /* Drop packets based on the loopback_packet_drop_ratio
94 * a ratio of 0.2 will drop one every 5 packets
95 */
96 loopback_packet_drop_state += loopback_packet_drop_ratio;
97 if (loopback_packet_drop_state >= 1.0f) {
98 /* Administrate we dropped a packet */
99 loopback_packet_drop_state -= 1.0f;
100 loopback_packet_dropped_count++;
101 return 0;
102 }
103 #endif
104
105 if (!pkt->frags) {
106 LOG_ERR("No data to send");
107 return -ENODATA;
108 }
109
110 /* We need to swap the IP addresses because otherwise
111 * the packet will be dropped.
112 */
113
114 if (net_pkt_family(pkt) == AF_INET6) {
115 struct in6_addr addr;
116
117 net_ipv6_addr_copy_raw((uint8_t *)&addr, NET_IPV6_HDR(pkt)->src);
118 net_ipv6_addr_copy_raw(NET_IPV6_HDR(pkt)->src,
119 NET_IPV6_HDR(pkt)->dst);
120 net_ipv6_addr_copy_raw(NET_IPV6_HDR(pkt)->dst, (uint8_t *)&addr);
121 } else {
122 struct in_addr addr;
123
124 net_ipv4_addr_copy_raw((uint8_t *)&addr, NET_IPV4_HDR(pkt)->src);
125 net_ipv4_addr_copy_raw(NET_IPV4_HDR(pkt)->src,
126 NET_IPV4_HDR(pkt)->dst);
127 net_ipv4_addr_copy_raw(NET_IPV4_HDR(pkt)->dst, (uint8_t *)&addr);
128 }
129
130 /* We should simulate normal driver meaning that if the packet is
131 * properly sent (which is always in this driver), then the packet
132 * must be dropped. This is very much needed for TCP packets where
133 * the packet is reference counted in various stages of sending.
134 */
135 cloned = net_pkt_rx_clone(pkt, K_MSEC(100));
136 if (!cloned) {
137 res = -ENOMEM;
138 goto out;
139 }
140
141 res = net_recv_data(net_pkt_iface(cloned), cloned);
142 if (res < 0) {
143 LOG_ERR("Data receive failed.");
144 }
145
146 out:
147 /* Let the receiving thread run now */
148 k_yield();
149
150 return res;
151 }
152
153 static struct dummy_api loopback_api = {
154 .iface_api.init = loopback_init,
155
156 .send = loopback_send,
157 };
158
159 NET_DEVICE_INIT(loopback, "lo",
160 loopback_dev_init, NULL, NULL, NULL,
161 CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,
162 &loopback_api, DUMMY_L2,
163 NET_L2_GET_CTX_TYPE(DUMMY_L2), CONFIG_NET_LOOPBACK_MTU);
164
