1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * user-mode-linux networking multicast transport
4 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 * Copyright (C) 2001 by Harald Welte <laforge@gnumonks.org>
6 *
7 * based on the existing uml-networking code, which is
8 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
9 * James Leu (jleu@mindspring.net).
10 * Copyright (C) 2001 by various other people who didn't put their name here.
11 *
12 *
13 */
14
15 #include <unistd.h>
16 #include <errno.h>
17 #include <netinet/in.h>
18 #include "umcast.h"
19 #include <net_user.h>
20 #include <um_malloc.h>
21
22 static struct sockaddr_in *new_addr(char *addr, unsigned short port)
23 {
24 struct sockaddr_in *sin;
25
26 sin = uml_kmalloc(sizeof(struct sockaddr_in), UM_GFP_KERNEL);
27 if (sin == NULL) {
28 printk(UM_KERN_ERR "new_addr: allocation of sockaddr_in "
29 "failed\n");
30 return NULL;
31 }
32 sin->sin_family = AF_INET;
33 if (addr)
34 sin->sin_addr.s_addr = in_aton(addr);
35 else
36 sin->sin_addr.s_addr = INADDR_ANY;
37 sin->sin_port = htons(port);
38 return sin;
39 }
40
41 static int umcast_user_init(void *data, void *dev)
42 {
43 struct umcast_data *pri = data;
44
45 pri->remote_addr = new_addr(pri->addr, pri->rport);
46 if (pri->unicast)
47 pri->listen_addr = new_addr(NULL, pri->lport);
48 else
49 pri->listen_addr = pri->remote_addr;
50 pri->dev = dev;
51 return 0;
52 }
53
54 static void umcast_remove(void *data)
55 {
56 struct umcast_data *pri = data;
57
58 kfree(pri->listen_addr);
59 if (pri->unicast)
60 kfree(pri->remote_addr);
61 pri->listen_addr = pri->remote_addr = NULL;
62 }
63
64 static int umcast_open(void *data)
65 {
66 struct umcast_data *pri = data;
67 struct sockaddr_in *lsin = pri->listen_addr;
68 struct sockaddr_in *rsin = pri->remote_addr;
69 struct ip_mreq mreq;
70 int fd, yes = 1, err = -EINVAL;
71
72
73 if ((!pri->unicast && lsin->sin_addr.s_addr == 0) ||
74 (rsin->sin_addr.s_addr == 0) ||
75 (lsin->sin_port == 0) || (rsin->sin_port == 0))
76 goto out;
77
78 fd = socket(AF_INET, SOCK_DGRAM, 0);
79
80 if (fd < 0) {
81 err = -errno;
82 printk(UM_KERN_ERR "umcast_open : data socket failed, "
83 "errno = %d\n", errno);
84 goto out;
85 }
86
87 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
88 err = -errno;
89 printk(UM_KERN_ERR "umcast_open: SO_REUSEADDR failed, "
90 "errno = %d\n", errno);
91 goto out_close;
92 }
93
94 if (!pri->unicast) {
95 /* set ttl according to config */
96 if (setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &pri->ttl,
97 sizeof(pri->ttl)) < 0) {
98 err = -errno;
99 printk(UM_KERN_ERR "umcast_open: IP_MULTICAST_TTL "
100 "failed, error = %d\n", errno);
101 goto out_close;
102 }
103
104 /* set LOOP, so data does get fed back to local sockets */
105 if (setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP,
106 &yes, sizeof(yes)) < 0) {
107 err = -errno;
108 printk(UM_KERN_ERR "umcast_open: IP_MULTICAST_LOOP "
109 "failed, error = %d\n", errno);
110 goto out_close;
111 }
112 }
113
114 /* bind socket to the address */
115 if (bind(fd, (struct sockaddr *) lsin, sizeof(*lsin)) < 0) {
116 err = -errno;
117 printk(UM_KERN_ERR "umcast_open : data bind failed, "
118 "errno = %d\n", errno);
119 goto out_close;
120 }
121
122 if (!pri->unicast) {
123 /* subscribe to the multicast group */
124 mreq.imr_multiaddr.s_addr = lsin->sin_addr.s_addr;
125 mreq.imr_interface.s_addr = 0;
126 if (setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP,
127 &mreq, sizeof(mreq)) < 0) {
128 err = -errno;
129 printk(UM_KERN_ERR "umcast_open: IP_ADD_MEMBERSHIP "
130 "failed, error = %d\n", errno);
131 printk(UM_KERN_ERR "There appears not to be a "
132 "multicast-capable network interface on the "
133 "host.\n");
134 printk(UM_KERN_ERR "eth0 should be configured in order "
135 "to use the multicast transport.\n");
136 goto out_close;
137 }
138 }
139
140 return fd;
141
142 out_close:
143 close(fd);
144 out:
145 return err;
146 }
147
148 static void umcast_close(int fd, void *data)
149 {
150 struct umcast_data *pri = data;
151
152 if (!pri->unicast) {
153 struct ip_mreq mreq;
154 struct sockaddr_in *lsin = pri->listen_addr;
155
156 mreq.imr_multiaddr.s_addr = lsin->sin_addr.s_addr;
157 mreq.imr_interface.s_addr = 0;
158 if (setsockopt(fd, SOL_IP, IP_DROP_MEMBERSHIP,
159 &mreq, sizeof(mreq)) < 0) {
160 printk(UM_KERN_ERR "umcast_close: IP_DROP_MEMBERSHIP "
161 "failed, error = %d\n", errno);
162 }
163 }
164
165 close(fd);
166 }
167
168 int umcast_user_write(int fd, void *buf, int len, struct umcast_data *pri)
169 {
170 struct sockaddr_in *data_addr = pri->remote_addr;
171
172 return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));
173 }
174
175 const struct net_user_info umcast_user_info = {
176 .init = umcast_user_init,
177 .open = umcast_open,
178 .close = umcast_close,
179 .remove = umcast_remove,
180 .add_address = NULL,
181 .delete_address = NULL,
182 .mtu = ETH_MAX_PACKET,
183 .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
184 };
185
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