af_inet6.c

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/*
 *	PF_INET6 socket protocol family
 *	Linux INET6 implementation 
 *
 *	Authors:
 *	Pedro Roque		<[e-mail]>	
 *
 *	Adapted from linux/net/ipv4/af_inet.c
 *
 *	$Id: af_inet6.c,v 1.65 2001/10/02 02:22:36 davem Exp $
 *
 * 	Fixes:
 *	piggy, Karl Knutson	:	Socket protocol table
 * 	Hideaki YOSHIFUJI	:	sin6_scope_id support
 * 	Arnaldo Melo		: 	check proc_net_create return, cleanups
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */


#include <linux/module.h>
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/version.h>

#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/icmpv6.h>
#include <linux/brlock.h>
#include <linux/smp_lock.h>

#include <net/ip.h>
#include <net/ipv6.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <net/ipip.h>
#include <net/protocol.h>
#include <net/inet_common.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#ifdef MODULE
static int unloadable = 0; /* XX: Turn to one when all is ok within the
			      module for allowing unload */
#endif

#if defined(MODULE) && LINUX_VERSION_CODE > 0x20115
MODULE_AUTHOR("Cast of dozens");
MODULE_DESCRIPTION("IPv6 protocol stack for Linux");
MODULE_PARM(unloadable, "i");
#endif

/* IPv6 procfs goodies... */

#ifdef CONFIG_PROC_FS
extern int raw6_get_info(char *, char **, off_t, int);
extern int tcp6_get_info(char *, char **, off_t, int);
extern int udp6_get_info(char *, char **, off_t, int);
extern int afinet6_get_info(char *, char **, off_t, int);
extern int afinet6_get_snmp(char *, char **, off_t, int);
#endif

#ifdef CONFIG_SYSCTL
extern void ipv6_sysctl_register(void);
extern void ipv6_sysctl_unregister(void);
#endif

#ifdef INET_REFCNT_DEBUG
atomic_t inet6_sock_nr;
#endif

/* The inetsw table contains everything that inet_create needs to
 * build a new socket.
 */
struct list_head inetsw6[SOCK_MAX];

static void inet6_sock_destruct(struct sock *sk)
{
	inet_sock_destruct(sk);

#ifdef INET_REFCNT_DEBUG
	atomic_dec(&inet6_sock_nr);
#endif
	MOD_DEC_USE_COUNT;
}

static int inet6_create(struct socket *sock, int protocol)
{
	struct sock *sk;
	struct list_head *p;
	struct inet_protosw *answer;

	sk = sk_alloc(PF_INET6, GFP_KERNEL, 1);
	if (sk == NULL) 
		goto do_oom;

	/* Look for the requested type/protocol pair. */
	answer = NULL;
	br_read_lock_bh(BR_NETPROTO_LOCK);
	list_for_each(p, &inetsw6[sock->type]) {
		answer = list_entry(p, struct inet_protosw, list);

		/* Check the non-wild match. */
		if (protocol == answer->protocol) {
			if (protocol != IPPROTO_IP)
				break;
		} else {
			/* Check for the two wild cases. */
			if (IPPROTO_IP == protocol) {
				protocol = answer->protocol;
				break;
			}
			if (IPPROTO_IP == answer->protocol)
				break;
		}
		answer = NULL;
	}
	br_read_unlock_bh(BR_NETPROTO_LOCK);

	if (!answer)
		goto free_and_badtype;
	if (answer->capability > 0 && !capable(answer->capability))
		goto free_and_badperm;
	if (!protocol)
		goto free_and_noproto;

	sock->ops = answer->ops;
	sock_init_data(sock, sk);

	sk->prot = answer->prot;
	sk->no_check = answer->no_check;
	if (INET_PROTOSW_REUSE & answer->flags)
		sk->reuse = 1;

	if (SOCK_RAW == sock->type) {
		sk->num = protocol;
		if (IPPROTO_RAW == protocol)
			sk->protinfo.af_inet.hdrincl = 1;
	}

	sk->destruct            = inet6_sock_destruct;
	sk->zapped		= 0;
	sk->family		= PF_INET6;
	sk->protocol		= protocol;

	sk->backlog_rcv		= answer->prot->backlog_rcv;

	sk->net_pinfo.af_inet6.hop_limit  = -1;
	sk->net_pinfo.af_inet6.mcast_hops = -1;
	sk->net_pinfo.af_inet6.mc_loop	  = 1;
	sk->net_pinfo.af_inet6.pmtudisc	  = IPV6_PMTUDISC_WANT;

	/* Init the ipv4 part of the socket since we can have sockets
	 * using v6 API for ipv4.
	 */
	sk->protinfo.af_inet.ttl	= 64;

	sk->protinfo.af_inet.mc_loop	= 1;
	sk->protinfo.af_inet.mc_ttl	= 1;
	sk->protinfo.af_inet.mc_index	= 0;
	sk->protinfo.af_inet.mc_list	= NULL;

	if (ipv4_config.no_pmtu_disc)
		sk->protinfo.af_inet.pmtudisc = IP_PMTUDISC_DONT;
	else
		sk->protinfo.af_inet.pmtudisc = IP_PMTUDISC_WANT;


#ifdef INET_REFCNT_DEBUG
	atomic_inc(&inet6_sock_nr);
	atomic_inc(&inet_sock_nr);
#endif
	MOD_INC_USE_COUNT;

	if (sk->num) {
		/* It assumes that any protocol which allows
		 * the user to assign a number at socket
		 * creation time automatically shares.
		 */
		sk->sport = ntohs(sk->num);
		sk->prot->hash(sk);
	}
	if (sk->prot->init) {
		int err = sk->prot->init(sk);
		if (err != 0) {
			MOD_DEC_USE_COUNT;
			inet_sock_release(sk);
			return err;
		}
	}
	return 0;

free_and_badtype:
	sk_free(sk);
	return -ESOCKTNOSUPPORT;
free_and_badperm:
	sk_free(sk);
	return -EPERM;
free_and_noproto:
	sk_free(sk);
	return -EPROTONOSUPPORT;
do_oom:
	return -ENOBUFS;
}


/* bind for INET6 API */
static int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
	struct sockaddr_in6 *addr=(struct sockaddr_in6 *)uaddr;
	struct sock *sk = sock->sk;
	__u32 v4addr = 0;
	unsigned short snum;
	int addr_type = 0;

	/* If the socket has its own bind function then use it. */
	if(sk->prot->bind)
		return sk->prot->bind(sk, uaddr, addr_len);

	if (addr_len < SIN6_LEN_RFC2133)
		return -EINVAL;
	addr_type = ipv6_addr_type(&addr->sin6_addr);
	if ((addr_type & IPV6_ADDR_MULTICAST) && sock->type == SOCK_STREAM)
		return -EINVAL;

	/* Check if the address belongs to the host. */
	if (addr_type == IPV6_ADDR_MAPPED) {
		v4addr = addr->sin6_addr.s6_addr32[3];
		if (inet_addr_type(v4addr) != RTN_LOCAL)
			return -EADDRNOTAVAIL;
	} else {
		if (addr_type != IPV6_ADDR_ANY) {
			/* ipv4 addr of the socket is invalid.  Only the
			 * unpecified and mapped address have a v4 equivalent.
			 */
			v4addr = LOOPBACK4_IPV6;
			if (!(addr_type & IPV6_ADDR_MULTICAST))	{
				if (!ipv6_chk_addr(&addr->sin6_addr, NULL))
					return -EADDRNOTAVAIL;
			}
		}
	}

	snum = ntohs(addr->sin6_port);
	if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE))
		return -EACCES;

	lock_sock(sk);

	/* Check these errors (active socket, double bind). */
	if ((sk->state != TCP_CLOSE)			||
	    (sk->num != 0)) {
		release_sock(sk);
		return -EINVAL;
	}

	if (addr_type & IPV6_ADDR_LINKLOCAL) {
		if (addr_len >= sizeof(struct sockaddr_in6) &&
		    addr->sin6_scope_id) {
			/* Override any existing binding, if another one
			 * is supplied by user.
			 */
			sk->bound_dev_if = addr->sin6_scope_id;
		}

		/* Binding to link-local address requires an interface */
		if (sk->bound_dev_if == 0) {
			release_sock(sk);
			return -EINVAL;
		}
	}

	sk->rcv_saddr = v4addr;
	sk->saddr = v4addr;

	ipv6_addr_copy(&sk->net_pinfo.af_inet6.rcv_saddr, &addr->sin6_addr);
		
	if (!(addr_type & IPV6_ADDR_MULTICAST))
		ipv6_addr_copy(&sk->net_pinfo.af_inet6.saddr, &addr->sin6_addr);

	/* Make sure we are allowed to bind here. */
	if (sk->prot->get_port(sk, snum) != 0) {
		sk->rcv_saddr = 0;
		sk->saddr = 0;
		memset(&sk->net_pinfo.af_inet6.rcv_saddr, 0, sizeof(struct in6_addr));
		memset(&sk->net_pinfo.af_inet6.saddr, 0, sizeof(struct in6_addr));

		release_sock(sk);
		return -EADDRINUSE;
	}

	if (addr_type != IPV6_ADDR_ANY)
		sk->userlocks |= SOCK_BINDADDR_LOCK;
	if (snum)
		sk->userlocks |= SOCK_BINDPORT_LOCK;
	sk->sport = ntohs(sk->num);
	sk->dport = 0;
	sk->daddr = 0;
	release_sock(sk);

	return 0;
}

static int inet6_release(struct socket *sock)
{
	struct sock *sk = sock->sk;

	if (sk == NULL)
		return -EINVAL;

	/* Free mc lists */
	ipv6_sock_mc_close(sk);

	return inet_release(sock);
}

int inet6_destroy_sock(struct sock *sk)
{
	struct sk_buff *skb;
	struct ipv6_txoptions *opt;

	/*
	 *	Release destination entry
	 */

	sk_dst_reset(sk);

	/* Release rx options */

	if ((skb = xchg(&sk->net_pinfo.af_inet6.pktoptions, NULL)) != NULL)
		kfree_skb(skb);

	/* Free flowlabels */
	fl6_free_socklist(sk);

	/* Free tx options */

	if ((opt = xchg(&sk->net_pinfo.af_inet6.opt, NULL)) != NULL)