ipv6.c

linux 内核源代码

		dccp_pr_debug("sk->sk_state == DCCP_TIME_WAIT: do_time_wait\n");
		inet_twsk_put(inet_twsk(sk));
		goto no_dccp_socket;
	}

	/*
	 * RFC 4340, sec. 9.2.1: Minimum Checksum Coverage
	 *	o if MinCsCov = 0, only packets with CsCov = 0 are accepted
	 *	o if MinCsCov > 0, also accept packets with CsCov >= MinCsCov
	 */
	min_cov = dccp_sk(sk)->dccps_pcrlen;
	if (dh->dccph_cscov  &&  (min_cov == 0 || dh->dccph_cscov < min_cov))  {
		dccp_pr_debug("Packet CsCov %d does not satisfy MinCsCov %d\n",
			      dh->dccph_cscov, min_cov);
		/* FIXME: send Data Dropped option (see also dccp_v4_rcv) */
		goto discard_and_relse;
	}

	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
		goto discard_and_relse;

	return sk_receive_skb(sk, skb, 1) ? -1 : 0;

no_dccp_socket:
	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto discard_it;
	/*
	 * Step 2:
	 *	If no socket ...
	 *		Generate Reset(No Connection) unless P.type == Reset
	 *		Drop packet and return
	 */
	if (dh->dccph_type != DCCP_PKT_RESET) {
		DCCP_SKB_CB(skb)->dccpd_reset_code =
					DCCP_RESET_CODE_NO_CONNECTION;
		dccp_v6_ctl_send_reset(sk, skb);
	}

discard_it:
	kfree_skb(skb);
	return 0;

discard_and_relse:
	sock_put(sk);
	goto discard_it;
}

static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
			   int addr_len)
{
	struct sockaddr_in6 *usin = (struct sockaddr_in6 *)uaddr;
	struct inet_connection_sock *icsk = inet_csk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct ipv6_pinfo *np = inet6_sk(sk);
	struct dccp_sock *dp = dccp_sk(sk);
	struct in6_addr *saddr = NULL, *final_p = NULL, final;
	struct flowi fl;
	struct dst_entry *dst;
	int addr_type;
	int err;

	dp->dccps_role = DCCP_ROLE_CLIENT;

	if (addr_len < SIN6_LEN_RFC2133)
		return -EINVAL;

	if (usin->sin6_family != AF_INET6)
		return -EAFNOSUPPORT;

	memset(&fl, 0, sizeof(fl));

	if (np->sndflow) {
		fl.fl6_flowlabel = usin->sin6_flowinfo & IPV6_FLOWINFO_MASK;
		IP6_ECN_flow_init(fl.fl6_flowlabel);
		if (fl.fl6_flowlabel & IPV6_FLOWLABEL_MASK) {
			struct ip6_flowlabel *flowlabel;
			flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
			if (flowlabel == NULL)
				return -EINVAL;
			ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
			fl6_sock_release(flowlabel);
		}
	}
	/*
	 * connect() to INADDR_ANY means loopback (BSD'ism).
	 */
	if (ipv6_addr_any(&usin->sin6_addr))
		usin->sin6_addr.s6_addr[15] = 1;

	addr_type = ipv6_addr_type(&usin->sin6_addr);

	if (addr_type & IPV6_ADDR_MULTICAST)
		return -ENETUNREACH;

	if (addr_type & IPV6_ADDR_LINKLOCAL) {
		if (addr_len >= sizeof(struct sockaddr_in6) &&
		    usin->sin6_scope_id) {
			/* If interface is set while binding, indices
			 * must coincide.
			 */
			if (sk->sk_bound_dev_if &&
			    sk->sk_bound_dev_if != usin->sin6_scope_id)
				return -EINVAL;

			sk->sk_bound_dev_if = usin->sin6_scope_id;
		}

		/* Connect to link-local address requires an interface */
		if (!sk->sk_bound_dev_if)
			return -EINVAL;
	}

	ipv6_addr_copy(&np->daddr, &usin->sin6_addr);
	np->flow_label = fl.fl6_flowlabel;

	/*
	 * DCCP over IPv4
	 */
	if (addr_type == IPV6_ADDR_MAPPED) {
		u32 exthdrlen = icsk->icsk_ext_hdr_len;
		struct sockaddr_in sin;

		SOCK_DEBUG(sk, "connect: ipv4 mapped\n");

		if (__ipv6_only_sock(sk))
			return -ENETUNREACH;

		sin.sin_family = AF_INET;
		sin.sin_port = usin->sin6_port;
		sin.sin_addr.s_addr = usin->sin6_addr.s6_addr32[3];

		icsk->icsk_af_ops = &dccp_ipv6_mapped;
		sk->sk_backlog_rcv = dccp_v4_do_rcv;

		err = dccp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
		if (err) {
			icsk->icsk_ext_hdr_len = exthdrlen;
			icsk->icsk_af_ops = &dccp_ipv6_af_ops;
			sk->sk_backlog_rcv = dccp_v6_do_rcv;
			goto failure;
		} else {
			ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000FFFF),
				      inet->saddr);
			ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000FFFF),
				      inet->rcv_saddr);
		}

		return err;
	}

	if (!ipv6_addr_any(&np->rcv_saddr))
		saddr = &np->rcv_saddr;

	fl.proto = IPPROTO_DCCP;
	ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
	ipv6_addr_copy(&fl.fl6_src, saddr ? saddr : &np->saddr);
	fl.oif = sk->sk_bound_dev_if;
	fl.fl_ip_dport = usin->sin6_port;
	fl.fl_ip_sport = inet->sport;
	security_sk_classify_flow(sk, &fl);

	if (np->opt != NULL && np->opt->srcrt != NULL) {
		const struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;

		ipv6_addr_copy(&final, &fl.fl6_dst);
		ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
		final_p = &final;
	}

	err = ip6_dst_lookup(sk, &dst, &fl);
	if (err)
		goto failure;

	if (final_p)
		ipv6_addr_copy(&fl.fl6_dst, final_p);

	err = __xfrm_lookup(&dst, &fl, sk, 1);
	if (err < 0) {
		if (err == -EREMOTE)
			err = ip6_dst_blackhole(sk, &dst, &fl);
		if (err < 0)
			goto failure;
	}

	if (saddr == NULL) {
		saddr = &fl.fl6_src;
		ipv6_addr_copy(&np->rcv_saddr, saddr);
	}

	/* set the source address */
	ipv6_addr_copy(&np->saddr, saddr);
	inet->rcv_saddr = LOOPBACK4_IPV6;

	__ip6_dst_store(sk, dst, NULL, NULL);

	icsk->icsk_ext_hdr_len = 0;
	if (np->opt != NULL)
		icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
					  np->opt->opt_nflen);

	inet->dport = usin->sin6_port;

	dccp_set_state(sk, DCCP_REQUESTING);
	err = inet6_hash_connect(&dccp_death_row, sk);
	if (err)
		goto late_failure;

	dp->dccps_iss = secure_dccpv6_sequence_number(np->saddr.s6_addr32,
						      np->daddr.s6_addr32,
						      inet->sport, inet->dport);
	err = dccp_connect(sk);
	if (err)
		goto late_failure;

	return 0;

late_failure:
	dccp_set_state(sk, DCCP_CLOSED);
	__sk_dst_reset(sk);
failure:
	inet->dport = 0;
	sk->sk_route_caps = 0;
	return err;
}

static struct inet_connection_sock_af_ops dccp_ipv6_af_ops = {
	.queue_xmit	   = inet6_csk_xmit,
	.send_check	   = dccp_v6_send_check,
	.rebuild_header	   = inet6_sk_rebuild_header,
	.conn_request	   = dccp_v6_conn_request,
	.syn_recv_sock	   = dccp_v6_request_recv_sock,
	.net_header_len	   = sizeof(struct ipv6hdr),
	.setsockopt	   = ipv6_setsockopt,
	.getsockopt	   = ipv6_getsockopt,
	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in6),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ipv6_setsockopt,
	.compat_getsockopt = compat_ipv6_getsockopt,
#endif
};

/*
 *	DCCP over IPv4 via INET6 API
 */
static struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
	.queue_xmit	   = ip_queue_xmit,
	.send_check	   = dccp_v4_send_check,
	.rebuild_header	   = inet_sk_rebuild_header,
	.conn_request	   = dccp_v6_conn_request,
	.syn_recv_sock	   = dccp_v6_request_recv_sock,
	.net_header_len	   = sizeof(struct iphdr),
	.setsockopt	   = ipv6_setsockopt,
	.getsockopt	   = ipv6_getsockopt,
	.addr2sockaddr	   = inet6_csk_addr2sockaddr,
	.sockaddr_len	   = sizeof(struct sockaddr_in6),
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_ipv6_setsockopt,
	.compat_getsockopt = compat_ipv6_getsockopt,
#endif
};

/* NOTE: A lot of things set to zero explicitly by call to
 *       sk_alloc() so need not be done here.
 */
static int dccp_v6_init_sock(struct sock *sk)
{
	static __u8 dccp_v6_ctl_sock_initialized;
	int err = dccp_init_sock(sk, dccp_v6_ctl_sock_initialized);

	if (err == 0) {
		if (unlikely(!dccp_v6_ctl_sock_initialized))
			dccp_v6_ctl_sock_initialized = 1;
		inet_csk(sk)->icsk_af_ops = &dccp_ipv6_af_ops;
	}

	return err;
}

static int dccp_v6_destroy_sock(struct sock *sk)
{
	dccp_destroy_sock(sk);
	return inet6_destroy_sock(sk);
}

static struct timewait_sock_ops dccp6_timewait_sock_ops = {
	.twsk_obj_size	= sizeof(struct dccp6_timewait_sock),
};

DEFINE_PROTO_INUSE(dccp_v6)

static struct proto dccp_v6_prot = {
	.name		   = "DCCPv6",
	.owner		   = THIS_MODULE,
	.close		   = dccp_close,
	.connect	   = dccp_v6_connect,
	.disconnect	   = dccp_disconnect,
	.ioctl		   = dccp_ioctl,
	.init		   = dccp_v6_init_sock,
	.setsockopt	   = dccp_setsockopt,
	.getsockopt	   = dccp_getsockopt,
	.sendmsg	   = dccp_sendmsg,
	.recvmsg	   = dccp_recvmsg,
	.backlog_rcv	   = dccp_v6_do_rcv,
	.hash		   = dccp_v6_hash,
	.unhash		   = dccp_unhash,
	.accept		   = inet_csk_accept,
	.get_port	   = dccp_v6_get_port,
	.shutdown	   = dccp_shutdown,
	.destroy	   = dccp_v6_destroy_sock,
	.orphan_count	   = &dccp_orphan_count,
	.max_header	   = MAX_DCCP_HEADER,
	.obj_size	   = sizeof(struct dccp6_sock),
	.rsk_prot	   = &dccp6_request_sock_ops,
	.twsk_prot	   = &dccp6_timewait_sock_ops,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_dccp_setsockopt,
	.compat_getsockopt = compat_dccp_getsockopt,
#endif
	REF_PROTO_INUSE(dccp_v6)
};

static struct inet6_protocol dccp_v6_protocol = {
	.handler	= dccp_v6_rcv,
	.err_handler	= dccp_v6_err,
	.flags		= INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
};

static struct proto_ops inet6_dccp_ops = {
	.family		   = PF_INET6,
	.owner		   = THIS_MODULE,
	.release	   = inet6_release,
	.bind		   = inet6_bind,
	.connect	   = inet_stream_connect,
	.socketpair	   = sock_no_socketpair,
	.accept		   = inet_accept,
	.getname	   = inet6_getname,
	.poll		   = dccp_poll,
	.ioctl		   = inet6_ioctl,
	.listen		   = inet_dccp_listen,
	.shutdown	   = inet_shutdown,
	.setsockopt	   = sock_common_setsockopt,
	.getsockopt	   = sock_common_getsockopt,
	.sendmsg	   = inet_sendmsg,
	.recvmsg	   = sock_common_recvmsg,
	.mmap		   = sock_no_mmap,
	.sendpage	   = sock_no_sendpage,
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_sock_common_setsockopt,
	.compat_getsockopt = compat_sock_common_getsockopt,
#endif
};

static struct inet_protosw dccp_v6_protosw = {
	.type		= SOCK_DCCP,
	.protocol	= IPPROTO_DCCP,
	.prot		= &dccp_v6_prot,
	.ops		= &inet6_dccp_ops,
	.capability	= -1,
	.flags		= INET_PROTOSW_ICSK,
};

static int __init dccp_v6_init(void)
{
	int err = proto_register(&dccp_v6_prot, 1);

	if (err != 0)
		goto out;

	err = inet6_add_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
	if (err != 0)
		goto out_unregister_proto;

	inet6_register_protosw(&dccp_v6_protosw);

	err = inet_csk_ctl_sock_create(&dccp_v6_ctl_socket, PF_INET6,
				       SOCK_DCCP, IPPROTO_DCCP);
	if (err != 0)
		goto out_unregister_protosw;
out:
	return err;
out_unregister_protosw:
	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
	inet6_unregister_protosw(&dccp_v6_protosw);
out_unregister_proto:
	proto_unregister(&dccp_v6_prot);
	goto out;
}

static void __exit dccp_v6_exit(void)
{
	inet6_del_protocol(&dccp_v6_protocol, IPPROTO_DCCP);
	inet6_unregister_protosw(&dccp_v6_protosw);
	proto_unregister(&dccp_v6_prot);
}

module_init(dccp_v6_init);
module_exit(dccp_v6_exit);

/*
 * __stringify doesn't likes enums, so use SOCK_DCCP (6) and IPPROTO_DCCP (33)
 * values directly, Also cover the case where the protocol is not specified,
 * i.e. net-pf-PF_INET6-proto-0-type-SOCK_DCCP
 */
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 33, 6);
MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 0, 6);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arnaldo Carvalho de Melo <[e-mail]>");
MODULE_DESCRIPTION("DCCPv6 - Datagram Congestion Controlled Protocol");