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
22static 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
41static 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
54static 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
64static 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
148static 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
168int 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
175const 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