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目录
net/ipv4/af_inet.c/inet_ioctl()
net/ipv4/devinet.c/devinet_ioctl()
net/ipv4/fib_frontend.c/ip_rt_ioctl()
ioctl() tour
Anatomy of ioctl() thread
PLEASE WAIT FOR THE EXPLANATION.
arch/i386/kernel/entry.S
ENTRY(sys_call_table)
.....
.long SYMBOL_NAME(sys_ioctl) /* 54 */fs/ioctl.c/sys_ioctl()
asmlinkage int sys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg)
{
struct file * filp;
unsigned int flag;
int on, error = -EBADF;
lock_kernel();
filp = fget(fd);
if (!filp)
goto out;
error = 0;
switch (cmd) {
.....
default:
.....
else if (filp->f_op && filp->f_op->ioctl)
error = filp->f_op->ioctl(filp->f_dentry->d_inode, filp, cmd, arg);
}
fput(filp);
out:
unlock_kernel();
return error;
}net/socket.c/sock_ioctl()
/*
* With an ioctl arg may well be a user mode pointer, but we don't know what to do
* with it - that's up to the protocol still.
*/
int sock_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
struct socket *sock = socki_lookup(inode);
return sock->ops->ioctl(sock, cmd, arg);
}net/ipv4/af_inet.c
struct proto_ops inet_stream_ops = {
PF_INET,
sock_no_dup,
inet_release,
inet_bind,
inet_stream_connect,
sock_no_socketpair,
inet_accept,
inet_getname,
inet_poll,
inet_ioctl,
inet_listen,
inet_shutdown,
inet_setsockopt,
inet_getsockopt,
sock_no_fcntl,
inet_sendmsg,
inet_recvmsg
};
struct proto_ops inet_dgram_ops = {
PF_INET,
sock_no_dup,
inet_release,
inet_bind,
inet_dgram_connect,
sock_no_socketpair,
sock_no_accept,
inet_getname,
datagram_poll,
inet_ioctl,
sock_no_listen,
inet_shutdown,
inet_setsockopt,
inet_getsockopt,
sock_no_fcntl,
inet_sendmsg,
inet_recvmsg
};net/ipv4/af_inet.c/inet_ioctl()
static int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
struct sock *sk = sock->sk;
int err;
int pid;
switch(cmd)
{
.....
case SIOCADDRT:
case SIOCDELRT:
case SIOCRTMSG:
return(ip_rt_ioctl(cmd,(void *) arg));
case SIOCDARP:
case SIOCGARP:
case SIOCSARP:
return(arp_ioctl(cmd,(void *) arg));
.....
case SIOCGIFADDR:
case SIOCSIFADDR:
case SIOCGIFBRDADDR:
case SIOCSIFBRDADDR:
case SIOCGIFNETMASK:
case SIOCSIFNETMASK:
case SIOCGIFDSTADDR:
case SIOCSIFDSTADDR:
case SIOCSIFPFLAGS:
case SIOCGIFPFLAGS:
case SIOCSIFFLAGS:
return(devinet_ioctl(cmd,(void *) arg));
.....
default:
// case SIOCGIFFLAGS:
// case SIOCSIFHWADDR:
// case SIOCGIFHWADDR:
// etc.
.....
if (sk->prot->ioctl==NULL || (err=sk->prot->ioctl(sk, cmd, arg))==-ENOIOCTLC
MD)
return(dev_ioctl(cmd,(void *) arg));
return err;
}
/*NOTREACHED*/
return(0);
}net/ipv4/devinet.c/devinet_ioctl()
int devinet_ioctl(unsigned int cmd, void *arg)
{
struct ifreq ifr;
struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
struct in_device *in_dev;
struct in_ifaddr **ifap = NULL;
struct in_ifaddr *ifa = NULL;
struct device *dev;
.....
switch(cmd) {
case SIOCGIFADDR: /* Get interface address */
case SIOCGIFBRDADDR: /* Get the broadcast address */
case SIOCGIFDSTADDR: /* Get the destination address */
case SIOCGIFNETMASK: /* Get the netmask for the interface */
/* Note that this ioctls will not sleep,
so that we do not impose a lock.
One day we will be forced to put shlock here (I mean SMP)
*/
memset(sin, 0, sizeof(*sin));
sin->sin_family = AF_INET;
break;
case SIOCSIFFLAGS:
if (!capable(CAP_NET_ADMIN))
return -EACCES;
rtnl_lock();
exclusive = 1;
break;
case SIOCSIFADDR: /* Set interface address (and family) */
case SIOCSIFBRDADDR: /* Set the broadcast address */
case SIOCSIFDSTADDR: /* Set the destination address */
case SIOCSIFNETMASK: /* Set the netmask for the interface */
if (!capable(CAP_NET_ADMIN))
return -EACCES;
if (sin->sin_family != AF_INET)
return -EINVAL;
rtnl_lock();
exclusive = 1;
break;
default:
return -EINVAL;
}
.....
switch(cmd) {
case SIOCGIFADDR: /* Get interface address */
sin->sin_addr.s_addr = ifa->ifa_local;
goto rarok;
case SIOCGIFBRDADDR: /* Get the broadcast address */
sin->sin_addr.s_addr = ifa->ifa_broadcast;
goto rarok;
case SIOCGIFDSTADDR: /* Get the destination address */
sin->sin_addr.s_addr = ifa->ifa_address;
goto rarok;
case SIOCGIFNETMASK: /* Get the netmask for the interface */
sin->sin_addr.s_addr = ifa->ifa_mask;
goto rarok;
case SIOCSIFFLAGS:
.....
ret = dev_change_flags(dev, ifr.ifr_flags);
break;
case SIOCSIFADDR: /* Set interface address (and family) */
.....
ifa->ifa_address =
ifa->ifa_local = sin->sin_addr.s_addr;
.....
ret = inet_set_ifa(dev, ifa);
break;
case SIOCSIFBRDADDR: /* Set the broadcast address */
.....
ifa->ifa_broadcast = sin->sin_addr.s_addr;
inet_insert_ifa(in_dev, ifa);
}
break;
case SIOCSIFDSTADDR: /* Set the destination address */
.....
ifa->ifa_address = sin->sin_addr.s_addr;
inet_insert_ifa(in_dev, ifa);
}
break;
case SIOCSIFNETMASK: /* Set the netmask for the interface */
.....
ifa->ifa_mask = sin->sin_addr.s_addr;
ifa->ifa_prefixlen = inet_mask_len(ifa->ifa_mask);
inet_set_ifa(dev, ifa);
}
break;
}
done:
if (exclusive)
rtnl_unlock();
return ret;
rarok:
if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
return -EFAULT;
return 0;
}net/core/dev.c/dev_ioctl()
/*
* This function handles all "interface"-type I/O control requests. The actual
* 'doing' part of this is dev_ifsioc above.
*/
int dev_ioctl(unsigned int cmd, void *arg)
{
struct ifreq ifr;
int ret;
char *colon;
.....
if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
return -EFAULT;
.....
/*
* See which interface the caller is talking about.
*/
switch(cmd)
{
/*
* These ioctl calls:
* - can be done by all.
* - atomic and do not require locking.
* - return a value
*/
case SIOCGIFFLAGS:
.....
case SIOCGIFHWADDR:
.....
dev_load(ifr.ifr_name);
ret = dev_ifsioc(&ifr, cmd);
if (!ret) {
if (colon)
*colon = ':';
if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
return -EFAULT;
}
return ret;
/*
* These ioctl calls:
* - require superuser power.
* - require strict serialization.
* - do not return a value
*/
.....
case SIOCSIFHWADDR:
.....
if (!capable(CAP_NET_ADMIN))
return -EPERM;
dev_load(ifr.ifr_name);
rtnl_lock();
ret = dev_ifsioc(&ifr, cmd);
rtnl_unlock();
return ret;
.....
}
}net/core/dev.c/dev_ifsioc()
/*
* Perform the SIOCxIFxxx calls.
*/
static int dev_ifsioc(struct ifreq *ifr, unsigned int cmd)
{
struct device *dev;
int err;
if ((dev = dev_get(ifr->ifr_name)) == NULL)
return -ENODEV;
switch(cmd)
{
case SIOCGIFFLAGS: /* Get interface flags */
ifr->ifr_flags = (dev->flags&~(IFF_PROMISC|IFF_ALLMULTI))
|(dev->gflags&(IFF_PROMISC|IFF_ALLMULTI));
return 0;
.....
case SIOCGIFHWADDR:
memcpy(ifr->ifr_hwaddr.sa_data,dev->dev_addr, MAX_ADDR_LEN);
ifr->ifr_hwaddr.sa_family=dev->type;
return 0;
case SIOCSIFHWADDR:
if(dev->set_mac_address==NULL)
return -EOPNOTSUPP;
if(ifr->ifr_hwaddr.sa_family!=dev->type)
return -EINVAL;
err=dev->set_mac_address(dev,&ifr->ifr_hwaddr);
if (!err)
notifier_call_chain(&netdev_chain, NETDEV_CHANGEADDR, dev);
return err;
.....
}
}net/ipv4/fib_frontend.c/ip_rt_ioctl()
/*
* Handle IP routing ioctl calls. These are used to manipulate the routing tables
*/
int ip_rt_ioctl(unsigned int cmd, void *arg)
{
int err;
struct kern_rta rta;
struct rtentry r;
struct {
struct nlmsghdr nlh;
struct rtmsg rtm;
} req;
switch (cmd) {
case SIOCADDRT: /* Add a route */
case SIOCDELRT: /* Delete a route */
if (!capable(CAP_NET_ADMIN))
return -EPERM;
if (copy_from_user(&r, arg, sizeof(struct rtentry)))
return -EFAULT;
rtnl_lock();
err = fib_convert_rtentry(cmd, &req.nlh, &req.rtm, &rta, &r);
if (err == 0) {
if (cmd == SIOCDELRT) {
struct fib_table *tb = fib_get_table(req.rtm.rtm_table);
err = -ESRCH;
if (tb)
err = tb->tb_delete(tb, &req.rtm, &rta, &req.nlh, NULL);
} else {
struct fib_table *tb = fib_new_table(req.rtm.rtm_table);
err = -ENOBUFS;
if (tb)
err = tb->tb_insert(tb, &req.rtm, &rta, &req.nlh, NULL);
}
if (rta.rta_mx)
kfree(rta.rta_mx);
}
rtnl_unlock();
return err;
}
return -EINVAL;
}To be continued.