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