ipv6.c

在linux环境下的流控制传输协议（sctp）的源代码

{
	return ipv6_addr_any(&addr->v6.sin6_addr);
}

/* Should this be available for binding?   */
static int sctp_v6_available(union sctp_addr *addr, struct sctp_sock *sp)
{
	int type;
	struct in6_addr *in6 = (struct in6_addr *)&addr->v6.sin6_addr;

	type = ipv6_addr_type(in6);
	if (IPV6_ADDR_ANY == type)
		return 1;
	if (type == IPV6_ADDR_MAPPED) {
		if (sp && !sp->v4mapped)
			return 0;
		if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
			return 0;
		sctp_v6_map_v4(addr);
		return sctp_get_af_specific(AF_INET)->available(addr, sp);
	}
	if (!(type & IPV6_ADDR_UNICAST))
		return 0;

	return ipv6_chk_addr(&init_net, in6, NULL, 0);
}

/* This function checks if the address is a valid address to be used for
 * SCTP.
 *
 * Output:
 * Return 0 - If the address is a non-unicast or an illegal address.
 * Return 1 - If the address is a unicast.
 */
static int sctp_v6_addr_valid(union sctp_addr *addr,
			      struct sctp_sock *sp,
			      const struct sk_buff *skb)
{
	int ret = ipv6_addr_type(&addr->v6.sin6_addr);

	/* Support v4-mapped-v6 address. */
	if (ret == IPV6_ADDR_MAPPED) {
		/* Note: This routine is used in input, so v4-mapped-v6
		 * are disallowed here when there is no sctp_sock.
		 */
		if (!sp || !sp->v4mapped)
			return 0;
		if (sp && ipv6_only_sock(sctp_opt2sk(sp)))
			return 0;
		sctp_v6_map_v4(addr);
		return sctp_get_af_specific(AF_INET)->addr_valid(addr, sp, skb);
	}

	/* Is this a non-unicast address */
	if (!(ret & IPV6_ADDR_UNICAST))
		return 0;

	return 1;
}

/* What is the scope of 'addr'?  */
static sctp_scope_t sctp_v6_scope(union sctp_addr *addr)
{
	int v6scope;
	sctp_scope_t retval;

	/* The IPv6 scope is really a set of bit fields.
	 * See IFA_* in <net/if_inet6.h>.  Map to a generic SCTP scope.
	 */

	v6scope = ipv6_addr_scope(&addr->v6.sin6_addr);
	switch (v6scope) {
	case IFA_HOST:
		retval = SCTP_SCOPE_LOOPBACK;
		break;
	case IFA_LINK:
		retval = SCTP_SCOPE_LINK;
		break;
	case IFA_SITE:
		retval = SCTP_SCOPE_PRIVATE;
		break;
	default:
		retval = SCTP_SCOPE_GLOBAL;
		break;
	}

	return retval;
}

/* Create and initialize a new sk for the socket to be returned by accept(). */
static struct sock *sctp_v6_create_accept_sk(struct sock *sk,
					     struct sctp_association *asoc)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sock *newsk;
	struct inet_sock *newinet;
	struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
	struct sctp6_sock *newsctp6sk;

	newsk = sk_alloc(sk->sk_net, PF_INET6, GFP_KERNEL, sk->sk_prot);
	if (!newsk)
		goto out;

	sock_init_data(NULL, newsk);

	newsk->sk_type = SOCK_STREAM;

	newsk->sk_prot = sk->sk_prot;
	newsk->sk_no_check = sk->sk_no_check;
	newsk->sk_reuse = sk->sk_reuse;

	newsk->sk_destruct = inet_sock_destruct;
	newsk->sk_family = PF_INET6;
	newsk->sk_protocol = IPPROTO_SCTP;
	newsk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
	newsk->sk_shutdown = sk->sk_shutdown;
	sock_reset_flag(sk, SOCK_ZAPPED);

	newsctp6sk = (struct sctp6_sock *)newsk;
	inet_sk(newsk)->pinet6 = &newsctp6sk->inet6;

	sctp_sk(newsk)->v4mapped = sctp_sk(sk)->v4mapped;

	newinet = inet_sk(newsk);
	newnp = inet6_sk(newsk);

	memcpy(newnp, np, sizeof(struct ipv6_pinfo));

	/* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname()
	 * and getpeername().
	 */
	newinet->sport = inet->sport;
	newnp->saddr = np->saddr;
	newnp->rcv_saddr = np->rcv_saddr;
	newinet->dport = htons(asoc->peer.port);
	sctp_v6_to_sk_daddr(&asoc->peer.primary_addr, newsk);

	/* Init the ipv4 part of the socket since we can have sockets
	 * using v6 API for ipv4.
	 */
	newinet->uc_ttl = -1;
	newinet->mc_loop = 1;
	newinet->mc_ttl = 1;
	newinet->mc_index = 0;
	newinet->mc_list = NULL;

	if (ipv4_config.no_pmtu_disc)
		newinet->pmtudisc = IP_PMTUDISC_DONT;
	else
		newinet->pmtudisc = IP_PMTUDISC_WANT;

	sk_refcnt_debug_inc(newsk);

	if (newsk->sk_prot->init(newsk)) {
		sk_common_release(newsk);
		newsk = NULL;
	}

out:
	return newsk;
}

/* Map v4 address to mapped v6 address */
static void sctp_v6_addr_v4map(struct sctp_sock *sp, union sctp_addr *addr)
{
	if (sp->v4mapped && AF_INET == addr->sa.sa_family)
		sctp_v4_map_v6(addr);
}

/* Where did this skb come from?  */
static int sctp_v6_skb_iif(const struct sk_buff *skb)
{
	struct inet6_skb_parm *opt = (struct inet6_skb_parm *) skb->cb;
	return opt->iif;
}

/* Was this packet marked by Explicit Congestion Notification? */
static int sctp_v6_is_ce(const struct sk_buff *skb)
{
	return *((__u32 *)(ipv6_hdr(skb))) & htonl(1 << 20);
}

/* Dump the v6 addr to the seq file. */
static void sctp_v6_seq_dump_addr(struct seq_file *seq, union sctp_addr *addr)
{
	seq_printf(seq, NIP6_FMT " ", NIP6(addr->v6.sin6_addr));
}

/* Initialize a PF_INET6 socket msg_name. */
static void sctp_inet6_msgname(char *msgname, int *addr_len)
{
	struct sockaddr_in6 *sin6;

	sin6 = (struct sockaddr_in6 *)msgname;
	sin6->sin6_family = AF_INET6;
	sin6->sin6_flowinfo = 0;
	sin6->sin6_scope_id = 0; /*FIXME */
	*addr_len = sizeof(struct sockaddr_in6);
}

/* Initialize a PF_INET msgname from a ulpevent. */
static void sctp_inet6_event_msgname(struct sctp_ulpevent *event,
				     char *msgname, int *addrlen)
{
	struct sockaddr_in6 *sin6, *sin6from;

	if (msgname) {
		union sctp_addr *addr;
		struct sctp_association *asoc;

		asoc = event->asoc;
		sctp_inet6_msgname(msgname, addrlen);
		sin6 = (struct sockaddr_in6 *)msgname;
		sin6->sin6_port = htons(asoc->peer.port);
		addr = &asoc->peer.primary_addr;

		/* Note: If we go to a common v6 format, this code
		 * will change.
		 */

		/* Map ipv4 address into v4-mapped-on-v6 address.  */
		if (sctp_sk(asoc->base.sk)->v4mapped &&
		    AF_INET == addr->sa.sa_family) {
			sctp_v4_map_v6((union sctp_addr *)sin6);
			sin6->sin6_addr.s6_addr32[3] =
				addr->v4.sin_addr.s_addr;
			return;
		}

		sin6from = &asoc->peer.primary_addr.v6;
		ipv6_addr_copy(&sin6->sin6_addr, &sin6from->sin6_addr);
		if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
			sin6->sin6_scope_id = sin6from->sin6_scope_id;
	}
}

/* Initialize a msg_name from an inbound skb. */
static void sctp_inet6_skb_msgname(struct sk_buff *skb, char *msgname,
				   int *addr_len)
{
	struct sctphdr *sh;
	struct sockaddr_in6 *sin6;

	if (msgname) {
		sctp_inet6_msgname(msgname, addr_len);
		sin6 = (struct sockaddr_in6 *)msgname;
		sh = sctp_hdr(skb);
		sin6->sin6_port = sh->source;

		/* Map ipv4 address into v4-mapped-on-v6 address. */
		if (sctp_sk(skb->sk)->v4mapped &&
		    ip_hdr(skb)->version == 4) {
			sctp_v4_map_v6((union sctp_addr *)sin6);
			sin6->sin6_addr.s6_addr32[3] = ip_hdr(skb)->saddr;
			return;
		}

		/* Otherwise, just copy the v6 address. */
		ipv6_addr_copy(&sin6->sin6_addr, &ipv6_hdr(skb)->saddr);
		if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL) {
			struct sctp_ulpevent *ev = sctp_skb2event(skb);
			sin6->sin6_scope_id = ev->iif;
		}
	}
}

/* Do we support this AF? */
static int sctp_inet6_af_supported(sa_family_t family, struct sctp_sock *sp)
{
	switch (family) {
	case AF_INET6:
		return 1;
	/* v4-mapped-v6 addresses */
	case AF_INET:
		if (!__ipv6_only_sock(sctp_opt2sk(sp)) && sp->v4mapped)
			return 1;
	default:
		return 0;
	}
}

/* Address matching with wildcards allowed.  This extra level
 * of indirection lets us choose whether a PF_INET6 should
 * disallow any v4 addresses if we so choose.
 */
static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
			       const union sctp_addr *addr2,
			       struct sctp_sock *opt)
{
	struct sctp_af *af1, *af2;

	af1 = sctp_get_af_specific(addr1->sa.sa_family);
	af2 = sctp_get_af_specific(addr2->sa.sa_family);

	if (!af1 || !af2)
		return 0;
	/* Today, wildcard AF_INET/AF_INET6. */
	if (sctp_is_any(addr1) || sctp_is_any(addr2))
		return 1;

	if (addr1->sa.sa_family != addr2->sa.sa_family)
		return 0;

	return af1->cmp_addr(addr1, addr2);
}

/* Verify that the provided sockaddr looks bindable.   Common verification,
 * has already been taken care of.
 */
static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
	struct sctp_af *af;

	/* ASSERT: address family has already been verified. */
	if (addr->sa.sa_family != AF_INET6)
		af = sctp_get_af_specific(addr->sa.sa_family);
	else {
		int type = ipv6_addr_type(&addr->v6.sin6_addr);
		struct net_device *dev;

		if (type & IPV6_ADDR_LINKLOCAL) {
			if (!addr->v6.sin6_scope_id)
				return 0;
			dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
			if (!dev)
				return 0;
			if (!ipv6_chk_addr(&init_net, &addr->v6.sin6_addr,
					   dev, 0)) {
				dev_put(dev);
				return 0;
			}
			dev_put(dev);
		}
		af = opt->pf->af;
	}
	return af->available(addr, opt);
}

/* Verify that the provided sockaddr looks sendable.   Common verification,
 * has already been taken care of.
 */
static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
{
	struct sctp_af *af = NULL;

	/* ASSERT: address family has already been verified. */
	if (addr->sa.sa_family != AF_INET6)
		af = sctp_get_af_specific(addr->sa.sa_family);
	else {
		int type = ipv6_addr_type(&addr->v6.sin6_addr);
		struct net_device *dev;

		if (type & IPV6_ADDR_LINKLOCAL) {
			if (!addr->v6.sin6_scope_id)
				return 0;
			dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
			if (!dev)
				return 0;
			dev_put(dev);
		}
		af = opt->pf->af;
	}

	return af != NULL;
}

/* Fill in Supported Address Type information for INIT and INIT-ACK
 * chunks.   Note: In the future, we may want to look at sock options
 * to determine whether a PF_INET6 socket really wants to have IPV4
 * addresses.
 * Returns number of addresses supported.
 */
static int sctp_inet6_supported_addrs(const struct sctp_sock *opt,
				      __be16 *types)
{
	types[0] = SCTP_PARAM_IPV4_ADDRESS;
	types[1] = SCTP_PARAM_IPV6_ADDRESS;
	return 2;
}

static const struct proto_ops inet6_seqpacket_ops = {
	.family		   = PF_INET6,
	.owner		   = THIS_MODULE,
	.release	   = inet6_release,
	.bind		   = inet6_bind,
	.connect	   = inet_dgram_connect,
	.socketpair	   = sock_no_socketpair,
	.accept		   = inet_accept,
	.getname	   = inet6_getname,
	.poll		   = sctp_poll,
	.ioctl		   = inet6_ioctl,
	.listen		   = sctp_inet_listen,
	.shutdown	   = inet_shutdown,
	.setsockopt	   = sock_common_setsockopt,
	.getsockopt	   = sock_common_getsockopt,
	.sendmsg	   = inet_sendmsg,
	.recvmsg	   = sock_common_recvmsg,
	.mmap		   = sock_no_mmap,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_sock_common_setsockopt,
	.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

static struct inet_protosw sctpv6_seqpacket_protosw = {
	.type          = SOCK_SEQPACKET,
	.protocol      = IPPROTO_SCTP,
	.prot 	       = &sctpv6_prot,
	.ops           = &inet6_seqpacket_ops,
	.capability    = -1,
	.no_check      = 0,
	.flags         = SCTP_PROTOSW_FLAG
};
static struct inet_protosw sctpv6_stream_protosw = {
	.type          = SOCK_STREAM,
	.protocol      = IPPROTO_SCTP,
	.prot 	       = &sctpv6_prot,
	.ops           = &inet6_seqpacket_ops,
	.capability    = -1,
	.no_check      = 0,
	.flags         = SCTP_PROTOSW_FLAG,
};

static int sctp6_rcv(struct sk_buff *skb)
{
	return sctp_rcv(skb) ? -1 : 0;
}

static struct inet6_protocol sctpv6_protocol = {
	.handler      = sctp6_rcv,
	.err_handler  = sctp_v6_err,
	.flags        = INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
};

static struct sctp_af sctp_af_inet6 = {
	.sa_family	   = AF_INET6,
	.sctp_xmit	   = sctp_v6_xmit,
	.setsockopt	   = ipv6_setsockopt,
	.getsockopt	   = ipv6_getsockopt,
	.get_dst	   = sctp_v6_get_dst,
	.get_saddr	   = sctp_v6_get_saddr,
	.copy_addrlist	   = sctp_v6_copy_addrlist,
	.from_skb	   = sctp_v6_from_skb,
	.from_sk	   = sctp_v6_from_sk,
	.to_sk_saddr	   = sctp_v6_to_sk_saddr,
	.to_sk_daddr	   = sctp_v6_to_sk_daddr,
	.from_addr_param   = sctp_v6_from_addr_param,
	.to_addr_param	   = sctp_v6_to_addr_param,
	.dst_saddr	   = sctp_v6_dst_saddr,
	.cmp_addr	   = sctp_v6_cmp_addr,
	.scope		   = sctp_v6_scope,
	.addr_valid	   = sctp_v6_addr_valid,
	.inaddr_any	   = sctp_v6_inaddr_any,
	.is_any		   = sctp_v6_is_any,
	.available	   = sctp_v6_available,
	.skb_iif	   = sctp_v6_skb_iif,
	.is_ce		   = sctp_v6_is_ce,
	.seq_dump_addr	   = sctp_v6_seq_dump_addr,
	.net_header_len	   = sizeof(struct ipv6hdr),
	.sockaddr_len	   = sizeof(struct sockaddr_in6),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ipv6_setsockopt,
	.compat_getsockopt = compat_ipv6_getsockopt,
#endif
};

static struct sctp_pf sctp_pf_inet6 = {
	.event_msgname = sctp_inet6_event_msgname,
	.skb_msgname   = sctp_inet6_skb_msgname,
	.af_supported  = sctp_inet6_af_supported,
	.cmp_addr      = sctp_inet6_cmp_addr,
	.bind_verify   = sctp_inet6_bind_verify,
	.send_verify   = sctp_inet6_send_verify,
	.supported_addrs = sctp_inet6_supported_addrs,
	.create_accept_sk = sctp_v6_create_accept_sk,
	.addr_v4map    = sctp_v6_addr_v4map,
	.af            = &sctp_af_inet6,
};

/* Initialize IPv6 support and register with socket layer.  */
void sctp_v6_pf_init(void)
{
	/* Register the SCTP specific PF_INET6 functions. */
	sctp_register_pf(&sctp_pf_inet6, PF_INET6);

	/* Register the SCTP specific AF_INET6 functions. */
	sctp_register_af(&sctp_af_inet6);
}

void sctp_v6_pf_exit(void)
{
	list_del(&sctp_af_inet6.list);
}

/* Initialize IPv6 support and register with socket layer.  */
int sctp_v6_protosw_init(void)
{
	int rc;

	rc = proto_register(&sctpv6_prot, 1);
	if (rc)
		return rc;

	/* Add SCTPv6(UDP and TCP style) to inetsw6 linked list. */
	inet6_register_protosw(&sctpv6_seqpacket_protosw);
	inet6_register_protosw(&sctpv6_stream_protosw);

	return 0;
}

void sctp_v6_protosw_exit(void)
{
	inet6_unregister_protosw(&sctpv6_seqpacket_protosw);
	inet6_unregister_protosw(&sctpv6_stream_protosw);
	proto_unregister(&sctpv6_prot);
}


/* Register with inet6 layer. */
int sctp_v6_add_protocol(void)
{
	/* Register notifier for inet6 address additions/deletions. */
	register_inet6addr_notifier(&sctp_inet6addr_notifier);

	if (inet6_add_protocol(&sctpv6_protocol, IPPROTO_SCTP) < 0)
		return -EAGAIN;

	return 0;
}

/* Unregister with inet6 layer. */
void sctp_v6_del_protocol(void)
{
	inet6_del_protocol(&sctpv6_protocol, IPPROTO_SCTP);
	unregister_inet6addr_notifier(&sctp_inet6addr_notifier);
}