/* connection-level event handling
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * 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/net.h>
  #include <linux/skbuff.h>
  #include <linux/errqueue.h>
  #include <linux/udp.h>
  #include <linux/in.h>
  #include <linux/in6.h>
  #include <linux/icmp.h>
  #include <net/sock.h>
  #include <net/af_rxrpc.h>
  #include <net/ip.h>
  #include "ar-internal.h"
  
  /*
   * pass a connection-level abort onto all calls on that connection
   */
  static void rxrpc_abort_calls(struct rxrpc_connection *conn, int state,
  			      u32 abort_code)
  {
  	struct rxrpc_call *call;
  	struct rb_node *p;
  
  	_enter("{%d},%x", conn->debug_id, abort_code);
  
  	read_lock_bh(&conn->lock);
  
  	for (p = rb_first(&conn->calls); p; p = rb_next(p)) {
  		call = rb_entry(p, struct rxrpc_call, conn_node);
  		write_lock(&call->state_lock);
  		if (call->state <= RXRPC_CALL_COMPLETE) {
  			call->state = state;
  			call->abort_code = abort_code;
  			if (state == RXRPC_CALL_LOCALLY_ABORTED)
  				set_bit(RXRPC_CALL_CONN_ABORT, &call->events);
  			else
  				set_bit(RXRPC_CALL_RCVD_ABORT, &call->events);

  			rxrpc_queue_call(call);

  		}
  		write_unlock(&call->state_lock);
  	}
  
  	read_unlock_bh(&conn->lock);
  	_leave("");
  }
  
  /*
   * generate a connection-level abort
   */
  static int rxrpc_abort_connection(struct rxrpc_connection *conn,
  				  u32 error, u32 abort_code)
  {
  	struct rxrpc_header hdr;
  	struct msghdr msg;
  	struct kvec iov[2];
  	__be32 word;
  	size_t len;
  	int ret;
  
  	_enter("%d,,%u,%u", conn->debug_id, error, abort_code);
  
  	/* generate a connection-level abort */
  	spin_lock_bh(&conn->state_lock);
  	if (conn->state < RXRPC_CONN_REMOTELY_ABORTED) {
  		conn->state = RXRPC_CONN_LOCALLY_ABORTED;
  		conn->error = error;
  		spin_unlock_bh(&conn->state_lock);
  	} else {
  		spin_unlock_bh(&conn->state_lock);
  		_leave(" = 0 [already dead]");
  		return 0;
  	}
  
  	rxrpc_abort_calls(conn, RXRPC_CALL_LOCALLY_ABORTED, abort_code);
  
  	msg.msg_name	= &conn->trans->peer->srx.transport.sin;
  	msg.msg_namelen	= sizeof(conn->trans->peer->srx.transport.sin);
  	msg.msg_control	= NULL;
  	msg.msg_controllen = 0;
  	msg.msg_flags	= 0;
  
  	hdr.epoch	= conn->epoch;
  	hdr.cid		= conn->cid;
  	hdr.callNumber	= 0;
  	hdr.seq		= 0;
  	hdr.type	= RXRPC_PACKET_TYPE_ABORT;
  	hdr.flags	= conn->out_clientflag;
  	hdr.userStatus	= 0;
  	hdr.securityIndex = conn->security_ix;
  	hdr._rsvd	= 0;
  	hdr.serviceId	= conn->service_id;
  
  	word = htonl(abort_code);
  
  	iov[0].iov_base	= &hdr;
  	iov[0].iov_len	= sizeof(hdr);
  	iov[1].iov_base	= &word;
  	iov[1].iov_len	= sizeof(word);
  
  	len = iov[0].iov_len + iov[1].iov_len;
  
  	hdr.serial = htonl(atomic_inc_return(&conn->serial));
  	_proto("Tx CONN ABORT %%%u { %d }", ntohl(hdr.serial), abort_code);
  
  	ret = kernel_sendmsg(conn->trans->local->socket, &msg, iov, 2, len);
  	if (ret < 0) {
  		_debug("sendmsg failed: %d", ret);
  		return -EAGAIN;
  	}
  
  	_leave(" = 0");
  	return 0;
  }
  
  /*
   * mark a call as being on a now-secured channel
   * - must be called with softirqs disabled
   */

  static void rxrpc_call_is_secure(struct rxrpc_call *call)

  {
  	_enter("%p", call);
  	if (call) {
  		read_lock(&call->state_lock);
  		if (call->state < RXRPC_CALL_COMPLETE &&
  		    !test_and_set_bit(RXRPC_CALL_SECURED, &call->events))

  			rxrpc_queue_call(call);

  		read_unlock(&call->state_lock);
  	}
  }
  
  /*
   * connection-level Rx packet processor
   */
  static int rxrpc_process_event(struct rxrpc_connection *conn,
  			       struct sk_buff *skb,
  			       u32 *_abort_code)
  {
  	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
  	__be32 tmp;
  	u32 serial;
  	int loop, ret;

  	if (conn->state >= RXRPC_CONN_REMOTELY_ABORTED) {
  		kleave(" = -ECONNABORTED [%u]", conn->state);

  		return -ECONNABORTED;

  	}

  
  	serial = ntohl(sp->hdr.serial);

  	_enter("{%d},{%u,%%%u},", conn->debug_id, sp->hdr.type, serial);

  	switch (sp->hdr.type) {
  	case RXRPC_PACKET_TYPE_ABORT:
  		if (skb_copy_bits(skb, 0, &tmp, sizeof(tmp)) < 0)
  			return -EPROTO;
  		_proto("Rx ABORT %%%u { ac=%d }", serial, ntohl(tmp));
  
  		conn->state = RXRPC_CONN_REMOTELY_ABORTED;
  		rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED,
  				  ntohl(tmp));
  		return -ECONNABORTED;
  
  	case RXRPC_PACKET_TYPE_CHALLENGE:
  		if (conn->security)
  			return conn->security->respond_to_challenge(
  				conn, skb, _abort_code);
  		return -EPROTO;
  
  	case RXRPC_PACKET_TYPE_RESPONSE:
  		if (!conn->security)
  			return -EPROTO;
  
  		ret = conn->security->verify_response(conn, skb, _abort_code);
  		if (ret < 0)
  			return ret;
  
  		ret = conn->security->init_connection_security(conn);
  		if (ret < 0)
  			return ret;
  
  		conn->security->prime_packet_security(conn);
  		read_lock_bh(&conn->lock);
  		spin_lock(&conn->state_lock);
  
  		if (conn->state == RXRPC_CONN_SERVER_CHALLENGING) {
  			conn->state = RXRPC_CONN_SERVER;
  			for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
  				rxrpc_call_is_secure(conn->channels[loop]);
  		}
  
  		spin_unlock(&conn->state_lock);
  		read_unlock_bh(&conn->lock);
  		return 0;
  
  	default:

  		_leave(" = -EPROTO [%u]", sp->hdr.type);

  		return -EPROTO;
  	}
  }
  
  /*
   * set up security and issue a challenge
   */
  static void rxrpc_secure_connection(struct rxrpc_connection *conn)
  {
  	u32 abort_code;
  	int ret;
  
  	_enter("{%d}", conn->debug_id);
  
  	ASSERT(conn->security_ix != 0);
  
  	if (!conn->key) {
  		_debug("set up security");
  		ret = rxrpc_init_server_conn_security(conn);
  		switch (ret) {
  		case 0:
  			break;
  		case -ENOENT:
  			abort_code = RX_CALL_DEAD;
  			goto abort;
  		default:
  			abort_code = RXKADNOAUTH;
  			goto abort;
  		}
  	}
  
  	ASSERT(conn->security != NULL);
  
  	if (conn->security->issue_challenge(conn) < 0) {
  		abort_code = RX_CALL_DEAD;
  		ret = -ENOMEM;
  		goto abort;
  	}
  
  	_leave("");
  	return;
  
  abort:
  	_debug("abort %d, %d", ret, abort_code);
  	rxrpc_abort_connection(conn, -ret, abort_code);
  	_leave(" [aborted]");
  }
  
  /*
   * connection-level event processor
   */
  void rxrpc_process_connection(struct work_struct *work)
  {
  	struct rxrpc_connection *conn =
  		container_of(work, struct rxrpc_connection, processor);

  	struct sk_buff *skb;
  	u32 abort_code = RX_PROTOCOL_ERROR;
  	int ret;
  
  	_enter("{%d}", conn->debug_id);
  
  	atomic_inc(&conn->usage);
  
  	if (test_and_clear_bit(RXRPC_CONN_CHALLENGE, &conn->events)) {
  		rxrpc_secure_connection(conn);
  		rxrpc_put_connection(conn);
  	}
  
  	/* go through the conn-level event packets, releasing the ref on this
  	 * connection that each one has when we've finished with it */
  	while ((skb = skb_dequeue(&conn->rx_queue))) {

  		ret = rxrpc_process_event(conn, skb, &abort_code);
  		switch (ret) {
  		case -EPROTO:
  		case -EKEYEXPIRED:
  		case -EKEYREJECTED:
  			goto protocol_error;
  		case -EAGAIN:
  			goto requeue_and_leave;
  		case -ECONNABORTED:
  		default:
  			rxrpc_put_connection(conn);
  			rxrpc_free_skb(skb);
  			break;
  		}
  	}
  
  out:
  	rxrpc_put_connection(conn);
  	_leave("");
  	return;
  
  requeue_and_leave:
  	skb_queue_head(&conn->rx_queue, skb);
  	goto out;
  
  protocol_error:
  	if (rxrpc_abort_connection(conn, -ret, abort_code) < 0)
  		goto requeue_and_leave;
  	rxrpc_put_connection(conn);
  	rxrpc_free_skb(skb);
  	_leave(" [EPROTO]");
  	goto out;
  }
  
  /*

   * put a packet up for transport-level abort
   */
  void rxrpc_reject_packet(struct rxrpc_local *local, struct sk_buff *skb)
  {
  	CHECK_SLAB_OKAY(&local->usage);
  
  	if (!atomic_inc_not_zero(&local->usage)) {
  		printk("resurrected on reject
  ");
  		BUG();
  	}
  
  	skb_queue_tail(&local->reject_queue, skb);
  	rxrpc_queue_work(&local->rejecter);
  }
  
  /*

   * reject packets through the local endpoint
   */
  void rxrpc_reject_packets(struct work_struct *work)
  {
  	union {
  		struct sockaddr sa;
  		struct sockaddr_in sin;
  	} sa;
  	struct rxrpc_skb_priv *sp;
  	struct rxrpc_header hdr;
  	struct rxrpc_local *local;
  	struct sk_buff *skb;
  	struct msghdr msg;
  	struct kvec iov[2];
  	size_t size;
  	__be32 code;
  
  	local = container_of(work, struct rxrpc_local, rejecter);
  	rxrpc_get_local(local);
  
  	_enter("%d", local->debug_id);
  
  	iov[0].iov_base = &hdr;
  	iov[0].iov_len = sizeof(hdr);
  	iov[1].iov_base = &code;
  	iov[1].iov_len = sizeof(code);
  	size = sizeof(hdr) + sizeof(code);
  
  	msg.msg_name = &sa;
  	msg.msg_control = NULL;
  	msg.msg_controllen = 0;
  	msg.msg_flags = 0;
  
  	memset(&sa, 0, sizeof(sa));
  	sa.sa.sa_family = local->srx.transport.family;
  	switch (sa.sa.sa_family) {
  	case AF_INET:
  		msg.msg_namelen = sizeof(sa.sin);
  		break;
  	default:
  		msg.msg_namelen = 0;
  		break;
  	}
  
  	memset(&hdr, 0, sizeof(hdr));
  	hdr.type = RXRPC_PACKET_TYPE_ABORT;
  
  	while ((skb = skb_dequeue(&local->reject_queue))) {
  		sp = rxrpc_skb(skb);
  		switch (sa.sa.sa_family) {
  		case AF_INET:
  			sa.sin.sin_port = udp_hdr(skb)->source;
  			sa.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
  			code = htonl(skb->priority);
  
  			hdr.epoch = sp->hdr.epoch;
  			hdr.cid = sp->hdr.cid;
  			hdr.callNumber = sp->hdr.callNumber;
  			hdr.serviceId = sp->hdr.serviceId;
  			hdr.flags = sp->hdr.flags;
  			hdr.flags ^= RXRPC_CLIENT_INITIATED;
  			hdr.flags &= RXRPC_CLIENT_INITIATED;
  
  			kernel_sendmsg(local->socket, &msg, iov, 2, size);
  			break;
  
  		default:
  			break;
  		}
  
  		rxrpc_free_skb(skb);
  		rxrpc_put_local(local);
  	}
  
  	rxrpc_put_local(local);
  	_leave("");
  }