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