arch/um/drivers/mcast_user.c

   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 "mcast.h"
  19 #include "net_user.h"
  20 #include "um_malloc.h"
  21 #include "user.h"
  22
  23 #define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)
  24
  25 static struct sockaddr_in *new_addr(char *addr, unsigned short port)
  26 {
  27         struct sockaddr_in *sin;
  28
  29         sin = kmalloc(sizeof(struct sockaddr_in), UM_GFP_KERNEL);
  30         if (sin == NULL) {
  31                 printk(UM_KERN_ERR "new_addr: allocation of sockaddr_in "
  32                        "failed\n");
  33                 return NULL;
  34         }
  35         sin->sin_family = AF_INET;
  36         sin->sin_addr.s_addr = in_aton(addr);
  37         sin->sin_port = htons(port);
  38         return sin;
  39 }
  40
  41 static int mcast_user_init(void *data, void *dev)
  42 {
  43         struct mcast_data *pri = data;
  44
  45         pri->mcast_addr = new_addr(pri->addr, pri->port);
  46         pri->dev = dev;
  47         return 0;
  48 }
  49
  50 static void mcast_remove(void *data)
  51 {
  52         struct mcast_data *pri = data;
  53
  54         kfree(pri->mcast_addr);
  55         pri->mcast_addr = NULL;
  56 }
  57
  58 static int mcast_open(void *data)
  59 {
  60         struct mcast_data *pri = data;
  61         struct sockaddr_in *sin = pri->mcast_addr;
  62         struct ip_mreq mreq;
  63         int fd, yes = 1, err = -EINVAL;
  64
  65
  66         if ((sin->sin_addr.s_addr == 0) || (sin->sin_port == 0))
  67                 goto out;
  68
  69         fd = socket(AF_INET, SOCK_DGRAM, 0);
  70
  71         if (fd < 0) {
  72                 err = -errno;
  73                 printk(UM_KERN_ERR "mcast_open : data socket failed, "
  74                        "errno = %d\n", errno);
  75                 goto out;
  76         }
  77
  78         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
  79                 err = -errno;
  80                 printk(UM_KERN_ERR "mcast_open: SO_REUSEADDR failed, "
  81                        "errno = %d\n", errno);
  82                 goto out_close;
  83         }
  84
  85         /* set ttl according to config */
  86         if (setsockopt(fd, SOL_IP, IP_MULTICAST_TTL, &pri->ttl,
  87                        sizeof(pri->ttl)) < 0) {
  88                 err = -errno;
  89                 printk(UM_KERN_ERR "mcast_open: IP_MULTICAST_TTL failed, "
  90                        "error = %d\n", errno);
  91                 goto out_close;
  92         }
  93
  94         /* set LOOP, so data does get fed back to local sockets */
  95         if (setsockopt(fd, SOL_IP, IP_MULTICAST_LOOP, &yes, sizeof(yes)) < 0) {
  96                 err = -errno;
  97                 printk(UM_KERN_ERR "mcast_open: IP_MULTICAST_LOOP failed, "
  98                        "error = %d\n", errno);
  99                 goto out_close;
 100         }
 101
 102         /* bind socket to mcast address */
 103         if (bind(fd, (struct sockaddr *) sin, sizeof(*sin)) < 0) {
 104                 err = -errno;
 105                 printk(UM_KERN_ERR "mcast_open : data bind failed, "
 106                        "errno = %d\n", errno);
 107                 goto out_close;
 108         }
 109
 110         /* subscribe to the multicast group */
 111         mreq.imr_multiaddr.s_addr = sin->sin_addr.s_addr;
 112         mreq.imr_interface.s_addr = 0;
 113         if (setsockopt(fd, SOL_IP, IP_ADD_MEMBERSHIP,
 114                        &mreq, sizeof(mreq)) < 0) {
 115                 err = -errno;
 116                 printk(UM_KERN_ERR "mcast_open: IP_ADD_MEMBERSHIP failed, "
 117                        "error = %d\n", errno);
 118                 printk(UM_KERN_ERR "There appears not to be a multicast-"
 119                        "capable network interface on the host.\n");
 120                 printk(UM_KERN_ERR "eth0 should be configured in order to use "
 121                        "the multicast transport.\n");
 122                 goto out_close;
 123         }
 124
 125         return fd;
 126
 127  out_close:
 128         close(fd);
 129  out:
 130         return err;
 131 }
 132
 133 static void mcast_close(int fd, void *data)
 134 {
 135         struct ip_mreq mreq;
 136         struct mcast_data *pri = data;
 137         struct sockaddr_in *sin = pri->mcast_addr;
 138
 139         mreq.imr_multiaddr.s_addr = sin->sin_addr.s_addr;
 140         mreq.imr_interface.s_addr = 0;
 141         if (setsockopt(fd, SOL_IP, IP_DROP_MEMBERSHIP,
 142                        &mreq, sizeof(mreq)) < 0) {
 143                 printk(UM_KERN_ERR "mcast_open: IP_DROP_MEMBERSHIP failed, "
 144                        "error = %d\n", errno);
 145         }
 146
 147         close(fd);
 148 }
 149
 150 int mcast_user_write(int fd, void *buf, int len, struct mcast_data *pri)
 151 {
 152         struct sockaddr_in *data_addr = pri->mcast_addr;
 153
 154         return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));
 155 }
 156
 157 static int mcast_set_mtu(int mtu, void *data)
 158 {
 159         return mtu;
 160 }
 161
 162 const struct net_user_info mcast_user_info = {
 163         .init           = mcast_user_init,
 164         .open           = mcast_open,
 165         .close          = mcast_close,
 166         .remove         = mcast_remove,
 167         .set_mtu        = mcast_set_mtu,
 168         .add_address    = NULL,
 169         .delete_address = NULL,
 170         .max_packet     = MAX_PACKET - ETH_HEADER_OTHER
 171 };