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1 /*
2  * user-mode-linux networking multicast transport
3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  * Copyright (C) 2001 by Harald Welte <laforge@gnumonks.org>
5  *
6  * based on the existing uml-networking code, which is
7  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
8  * James Leu (jleu@mindspring.net).
9  * Copyright (C) 2001 by various other people who didn't put their name here.
10  *
11  * Licensed under the GPL.
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 
new_addr(char * addr,unsigned short port)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 
umcast_user_init(void * data,void * dev)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 
umcast_remove(void * data)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 
umcast_open(void * data)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 
umcast_close(int fd,void * data)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 
umcast_user_write(int fd,void * buf,int len,struct umcast_data * pri)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