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* user-mode-linux networking multicast transport
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* Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Copyright (C) 2001 by Harald Welte <laforge@gnumonks.org>
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* based on the existing uml-networking code, which is
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* Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
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* James Leu (jleu@mindspring.net).
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* Copyright (C) 2001 by various other people who didn't put their name here.
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* Licensed under the GPL.
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#include <netinet/in.h>
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#include "kern_constants.h"
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#include "um_malloc.h"
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static struct sockaddr_in *new_addr(char *addr, unsigned short port)
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struct sockaddr_in *sin;
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sin = uml_kmalloc(sizeof(struct sockaddr_in), UM_GFP_KERNEL);
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printk(UM_KERN_ERR "new_addr: allocation of sockaddr_in "
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sin->sin_family = AF_INET;
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sin->sin_addr.s_addr = in_aton(addr);
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sin->sin_port = htons(port);
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static int mcast_user_init(void *data, void *dev)
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struct mcast_data *pri = data;
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pri->mcast_addr = new_addr(pri->addr, pri->port);
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static void mcast_remove(void *data)
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struct mcast_data *pri = data;
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kfree(pri->mcast_addr);
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pri->mcast_addr = NULL;
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static int mcast_open(void *data)
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struct mcast_data *pri = data;
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struct sockaddr_in *sin = pri->mcast_addr;
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int fd, yes = 1, err = -EINVAL;
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if ((sin->sin_addr.s_addr == 0) || (sin->sin_port == 0))
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fd = socket(AF_INET, SOCK_DGRAM, 0);
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printk(UM_KERN_ERR "mcast_open : data socket failed, "
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"errno = %d\n", errno);
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if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
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printk(UM_KERN_ERR "mcast_open: SO_REUSEADDR failed, "
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"errno = %d\n", errno);
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/* set ttl according to config */
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if (setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &pri->ttl,
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sizeof(pri->ttl)) < 0) {
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printk(UM_KERN_ERR "mcast_open: IP_MULTICAST_TTL failed, "
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"error = %d\n", errno);
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/* set LOOP, so data does get fed back to local sockets */
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if (setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &yes, sizeof(yes)) < 0) {
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printk(UM_KERN_ERR "mcast_open: IP_MULTICAST_LOOP failed, "
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"error = %d\n", errno);
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/* bind socket to mcast address */
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if (bind(fd, (struct sockaddr *) sin, sizeof(*sin)) < 0) {
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printk(UM_KERN_ERR "mcast_open : data bind failed, "
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"errno = %d\n", errno);
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/* subscribe to the multicast group */
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mreq.imr_multiaddr.s_addr = sin->sin_addr.s_addr;
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mreq.imr_interface.s_addr = 0;
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if (setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP,
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&mreq, sizeof(mreq)) < 0) {
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printk(UM_KERN_ERR "mcast_open: IP_ADD_MEMBERSHIP failed, "
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"error = %d\n", errno);
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printk(UM_KERN_ERR "There appears not to be a multicast-"
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"capable network interface on the host.\n");
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printk(UM_KERN_ERR "eth0 should be configured in order to use "
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"the multicast transport.\n");
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static void mcast_close(int fd, void *data)
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struct mcast_data *pri = data;
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struct sockaddr_in *sin = pri->mcast_addr;
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mreq.imr_multiaddr.s_addr = sin->sin_addr.s_addr;
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mreq.imr_interface.s_addr = 0;
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if (setsockopt(fd, SOL_IP, IP_DROP_MEMBERSHIP,
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&mreq, sizeof(mreq)) < 0) {
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printk(UM_KERN_ERR "mcast_open: IP_DROP_MEMBERSHIP failed, "
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"error = %d\n", errno);
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int mcast_user_write(int fd, void *buf, int len, struct mcast_data *pri)
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struct sockaddr_in *data_addr = pri->mcast_addr;
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return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));
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const struct net_user_info mcast_user_info = {
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.init = mcast_user_init,
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.close = mcast_close,
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.remove = mcast_remove,
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.delete_address = NULL,
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.mtu = ETH_MAX_PACKET,
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.max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,