transport.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 865 行 · 第 1/2 页

	_leave(" = 0 #%d", atomic_read(&rxrpc_message_count));
	return 0;

 error:
	while (!list_empty(msgq)) {
		msg = list_entry(msgq->next, struct rxrpc_message, link);
		list_del_init(&msg->link);

		rxrpc_put_message(msg);
	}

	_leave(" = %d", ret);
	return ret;
} /* end rxrpc_incoming_msg() */

/*****************************************************************************/
/*
 * accept a new call
 * - called from krxiod in process context
 */
void rxrpc_trans_receive_packet(struct rxrpc_transport *trans)
{
	struct rxrpc_message *msg;
	struct rxrpc_peer *peer;
	struct sk_buff *pkt;
	int ret;
	__be32 addr;
	__be16 port;

	LIST_HEAD(msgq);

	_enter("%p{%d}", trans, trans->port);

	for (;;) {
		/* deal with outstanting errors first */
		if (trans->error_rcvd)
			rxrpc_trans_receive_error_report(trans);

		/* attempt to receive a packet */
		pkt = skb_recv_datagram(trans->socket->sk, 0, 1, &ret);
		if (!pkt) {
			if (ret == -EAGAIN) {
				_leave(" EAGAIN");
				return;
			}

			/* an icmp error may have occurred */
			rxrpc_krxiod_queue_transport(trans);
			_leave(" error %d\n", ret);
			return;
		}

		/* we'll probably need to checksum it (didn't call
		 * sock_recvmsg) */
		if (pkt->ip_summed != CHECKSUM_UNNECESSARY) {
			if ((unsigned short)
			    csum_fold(skb_checksum(pkt, 0, pkt->len,
						   pkt->csum))) {
				kfree_skb(pkt);
				rxrpc_krxiod_queue_transport(trans);
				_leave(" CSUM failed");
				return;
			}
		}

		addr = pkt->nh.iph->saddr;
		port = pkt->h.uh->source;

		_net("Rx Received UDP packet from %08x:%04hu",
		     ntohl(addr), ntohs(port));

		/* unmarshall the Rx parameters and split jumbo packets */
		ret = rxrpc_incoming_msg(trans, pkt, &msgq);
		if (ret < 0) {
			kfree_skb(pkt);
			rxrpc_krxiod_queue_transport(trans);
			_leave(" bad packet");
			return;
		}

		BUG_ON(list_empty(&msgq));

		msg = list_entry(msgq.next, struct rxrpc_message, link);

		/* locate the record for the peer from which it
		 * originated */
		ret = rxrpc_peer_lookup(trans, addr, &peer);
		if (ret < 0) {
			kdebug("Rx No connections from that peer");
			rxrpc_trans_immediate_abort(trans, msg, -EINVAL);
			goto finished_msg;
		}

		/* try and find a matching connection */
		ret = rxrpc_connection_lookup(peer, msg, &msg->conn);
		if (ret < 0) {
			kdebug("Rx Unknown Connection");
			rxrpc_trans_immediate_abort(trans, msg, -EINVAL);
			rxrpc_put_peer(peer);
			goto finished_msg;
		}
		rxrpc_put_peer(peer);

		/* deal with the first packet of a new call */
		if (msg->hdr.flags & RXRPC_CLIENT_INITIATED &&
		    msg->hdr.type == RXRPC_PACKET_TYPE_DATA &&
		    ntohl(msg->hdr.seq) == 1
		    ) {
			_debug("Rx New server call");
			rxrpc_trans_receive_new_call(trans, &msgq);
			goto finished_msg;
		}

		/* deal with subsequent packet(s) of call */
		_debug("Rx Call packet");
		while (!list_empty(&msgq)) {
			msg = list_entry(msgq.next, struct rxrpc_message, link);
			list_del_init(&msg->link);

			ret = rxrpc_conn_receive_call_packet(msg->conn, NULL, msg);
			if (ret < 0) {
				rxrpc_trans_immediate_abort(trans, msg, ret);
				rxrpc_put_message(msg);
				goto finished_msg;
			}

			rxrpc_put_message(msg);
		}

		goto finished_msg;

		/* dispose of the packets */
	finished_msg:
		while (!list_empty(&msgq)) {
			msg = list_entry(msgq.next, struct rxrpc_message, link);
			list_del_init(&msg->link);

			rxrpc_put_message(msg);
		}
		kfree_skb(pkt);
	}

	_leave("");

} /* end rxrpc_trans_receive_packet() */

/*****************************************************************************/
/*
 * accept a new call from a client trying to connect to one of my services
 * - called in process context
 */
static int rxrpc_trans_receive_new_call(struct rxrpc_transport *trans,
					struct list_head *msgq)
{
	struct rxrpc_message *msg;

	_enter("");

	/* only bother with the first packet */
	msg = list_entry(msgq->next, struct rxrpc_message, link);
	list_del_init(&msg->link);
	rxrpc_krxsecd_queue_incoming_call(msg);
	rxrpc_put_message(msg);

	_leave(" = 0");

	return 0;
} /* end rxrpc_trans_receive_new_call() */

/*****************************************************************************/
/*
 * perform an immediate abort without connection or call structures
 */
int rxrpc_trans_immediate_abort(struct rxrpc_transport *trans,
				struct rxrpc_message *msg,
				int error)
{
	struct rxrpc_header ahdr;
	struct sockaddr_in sin;
	struct msghdr msghdr;
	struct kvec iov[2];
	__be32 _error;
	int len, ret;

	_enter("%p,%p,%d", trans, msg, error);

	/* don't abort an abort packet */
	if (msg->hdr.type == RXRPC_PACKET_TYPE_ABORT) {
		_leave(" = 0");
		return 0;
	}

	_error = htonl(-error);

	/* set up the message to be transmitted */
	memcpy(&ahdr, &msg->hdr, sizeof(ahdr));
	ahdr.epoch	= msg->hdr.epoch;
	ahdr.serial	= htonl(1);
	ahdr.seq	= 0;
	ahdr.type	= RXRPC_PACKET_TYPE_ABORT;
	ahdr.flags	= RXRPC_LAST_PACKET;
	ahdr.flags	|= ~msg->hdr.flags & RXRPC_CLIENT_INITIATED;

	iov[0].iov_len	= sizeof(ahdr);
	iov[0].iov_base	= &ahdr;
	iov[1].iov_len	= sizeof(_error);
	iov[1].iov_base	= &_error;

	len = sizeof(ahdr) + sizeof(_error);

	memset(&sin,0,sizeof(sin));
	sin.sin_family		= AF_INET;
	sin.sin_port		= msg->pkt->h.uh->source;
	sin.sin_addr.s_addr	= msg->pkt->nh.iph->saddr;

	msghdr.msg_name		= &sin;
	msghdr.msg_namelen	= sizeof(sin);
	msghdr.msg_control	= NULL;
	msghdr.msg_controllen	= 0;
	msghdr.msg_flags	= MSG_DONTWAIT;

	_net("Sending message type %d of %d bytes to %08x:%d",
	     ahdr.type,
	     len,
	     ntohl(sin.sin_addr.s_addr),
	     ntohs(sin.sin_port));

	/* send the message */
	ret = kernel_sendmsg(trans->socket, &msghdr, iov, 2, len);

	_leave(" = %d", ret);
	return ret;
} /* end rxrpc_trans_immediate_abort() */

/*****************************************************************************/
/*
 * receive an ICMP error report and percolate it to all connections
 * heading to the affected host or port
 */
static void rxrpc_trans_receive_error_report(struct rxrpc_transport *trans)
{
	struct rxrpc_connection *conn;
	struct sockaddr_in sin;
	struct rxrpc_peer *peer;
	struct list_head connq, *_p;
	struct errormsg emsg;
	struct msghdr msg;
	__be16 port;
	int local, err;

	_enter("%p", trans);

	for (;;) {
		trans->error_rcvd = 0;

		/* try and receive an error message */
		msg.msg_name	= &sin;
		msg.msg_namelen	= sizeof(sin);
		msg.msg_control	= &emsg;
		msg.msg_controllen = sizeof(emsg);
		msg.msg_flags	= 0;

		err = kernel_recvmsg(trans->socket, &msg, NULL, 0, 0,
				   MSG_ERRQUEUE | MSG_DONTWAIT | MSG_TRUNC);

		if (err == -EAGAIN) {
			_leave("");
			return;
		}

		if (err < 0) {
			printk("%s: unable to recv an error report: %d\n",
			       __FUNCTION__, err);
			_leave("");
			return;
		}

		msg.msg_controllen = (char *) msg.msg_control - (char *) &emsg;

		if (msg.msg_controllen < sizeof(emsg.cmsg) ||
		    msg.msg_namelen < sizeof(sin)) {
			printk("%s: short control message"
			       " (nlen=%u clen=%Zu fl=%x)\n",
			       __FUNCTION__,
			       msg.msg_namelen,
			       msg.msg_controllen,
			       msg.msg_flags);
			continue;
		}

		_net("Rx Received control message"
		     " { len=%Zu level=%u type=%u }",
		     emsg.cmsg.cmsg_len,
		     emsg.cmsg.cmsg_level,
		     emsg.cmsg.cmsg_type);

		if (sin.sin_family != AF_INET) {
			printk("Rx Ignoring error report with non-INET address"
			       " (fam=%u)",
			       sin.sin_family);
			continue;
		}

		_net("Rx Received message pertaining to host addr=%x port=%hu",
		     ntohl(sin.sin_addr.s_addr), ntohs(sin.sin_port));

		if (emsg.cmsg.cmsg_level != SOL_IP ||
		    emsg.cmsg.cmsg_type != IP_RECVERR) {
			printk("Rx Ignoring unknown error report"
			       " { level=%u type=%u }",
			       emsg.cmsg.cmsg_level,
			       emsg.cmsg.cmsg_type);
			continue;
		}

		if (msg.msg_controllen < sizeof(emsg.cmsg) + sizeof(emsg.ee)) {
			printk("%s: short error message (%Zu)\n",
			       __FUNCTION__, msg.msg_controllen);
			_leave("");
			return;
		}

		port = sin.sin_port;

		switch (emsg.ee.ee_origin) {
		case SO_EE_ORIGIN_ICMP:
			local = 0;
			switch (emsg.ee.ee_type) {
			case ICMP_DEST_UNREACH:
				switch (emsg.ee.ee_code) {
				case ICMP_NET_UNREACH:
					_net("Rx Received ICMP Network Unreachable");
					port = 0;
					err = -ENETUNREACH;
					break;
				case ICMP_HOST_UNREACH:
					_net("Rx Received ICMP Host Unreachable");
					port = 0;
					err = -EHOSTUNREACH;
					break;
				case ICMP_PORT_UNREACH:
					_net("Rx Received ICMP Port Unreachable");
					err = -ECONNREFUSED;
					break;
				case ICMP_NET_UNKNOWN:
					_net("Rx Received ICMP Unknown Network");
					port = 0;
					err = -ENETUNREACH;
					break;
				case ICMP_HOST_UNKNOWN:
					_net("Rx Received ICMP Unknown Host");
					port = 0;
					err = -EHOSTUNREACH;
					break;
				default:
					_net("Rx Received ICMP DestUnreach { code=%u }",
					     emsg.ee.ee_code);
					err = emsg.ee.ee_errno;
					break;
				}
				break;

			case ICMP_TIME_EXCEEDED:
				_net("Rx Received ICMP TTL Exceeded");
				err = emsg.ee.ee_errno;
				break;

			default:
				_proto("Rx Received ICMP error { type=%u code=%u }",
				       emsg.ee.ee_type, emsg.ee.ee_code);
				err = emsg.ee.ee_errno;
				break;
			}
			break;

		case SO_EE_ORIGIN_LOCAL:
			_proto("Rx Received local error { error=%d }",
			       emsg.ee.ee_errno);
			local = 1;
			err = emsg.ee.ee_errno;
			break;

		case SO_EE_ORIGIN_NONE:
		case SO_EE_ORIGIN_ICMP6:
		default:
			_proto("Rx Received error report { orig=%u }",
			       emsg.ee.ee_origin);
			local = 0;
			err = emsg.ee.ee_errno;
			break;
		}

		/* find all the connections between this transport and the
		 * affected destination */
		INIT_LIST_HEAD(&connq);

		if (rxrpc_peer_lookup(trans, sin.sin_addr.s_addr,
				      &peer) == 0) {
			read_lock(&peer->conn_lock);
			list_for_each(_p, &peer->conn_active) {
				conn = list_entry(_p, struct rxrpc_connection,
						  link);
				if (port && conn->addr.sin_port != port)
					continue;
				if (!list_empty(&conn->err_link))
					continue;

				rxrpc_get_connection(conn);
				list_add_tail(&conn->err_link, &connq);
			}
			read_unlock(&peer->conn_lock);

			/* service all those connections */
			while (!list_empty(&connq)) {
				conn = list_entry(connq.next,
						  struct rxrpc_connection,
						  err_link);
				list_del(&conn->err_link);

				rxrpc_conn_handle_error(conn, local, err);

				rxrpc_put_connection(conn);
			}

			rxrpc_put_peer(peer);
		}
	}

	_leave("");
	return;
} /* end rxrpc_trans_receive_error_report() */