C++ rxrpc_skb函数代码示例

/*
 * Process event packets targetted at a local endpoint.
 */
void rxrpc_process_local_events(struct rxrpc_local *local)
{
	struct sk_buff *skb;
	char v;

	_enter("");

	skb = skb_dequeue(&local->event_queue);
	if (skb) {
		struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
		_debug("{%d},{%u}", local->debug_id, sp->hdr.type);

		switch (sp->hdr.type) {
		case RXRPC_PACKET_TYPE_VERSION:
			if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
					  &v, 1) < 0)
				return;
			_proto("Rx VERSION { %02x }", v);
			if (v == 0)
				rxrpc_send_version_request(local, &sp->hdr, skb);
			break;

		default:
			/* Just ignore anything we don't understand */
			break;
		}

		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
	}

	_leave("");
}

/*
 * queue a packet for recvmsg to pass to userspace
 * - the caller must hold a lock on call->lock
 * - must not be called with interrupts disabled (sk_filter() disables BH's)
 * - eats the packet whether successful or not
 * - there must be just one reference to the packet, which the caller passes to
 *   this function
 */
int rxrpc_queue_rcv_skb(struct rxrpc_call *call, struct sk_buff *skb,
			bool force, bool terminal)
{
	struct rxrpc_skb_priv *sp;
	struct rxrpc_sock *rx = call->socket;
	struct sock *sk;
	int ret;

	_enter(",,%d,%d", force, terminal);

	ASSERT(!irqs_disabled());

	sp = rxrpc_skb(skb);
	ASSERTCMP(sp->call, ==, call);

	/* if we've already posted the terminal message for a call, then we
	 * don't post any more */
	if (test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
		_debug("already terminated");
		ASSERTCMP(call->state, >=, RXRPC_CALL_COMPLETE);
		skb->destructor = NULL;
		sp->call = NULL;
		rxrpc_put_call(call);
		rxrpc_free_skb(skb);
		return 0;
	}

/**
 * rxrpc_kernel_is_data_last - Determine if data message is last one
 * @skb: Message holding data
 *
 * Determine if data message is last one for the parent call.
 */
bool rxrpc_kernel_is_data_last(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_DATA);

	return sp->hdr.flags & RXRPC_LAST_PACKET;
}

/**
 * rxrpc_kernel_get_abort_code - Get the abort code from an RxRPC abort message
 * @skb: Message indicating an abort
 *
 * Get the abort code from an RxRPC abort message.
 */
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	ASSERTCMP(skb->mark, ==, RXRPC_SKB_MARK_REMOTE_ABORT);

	return sp->call->abort_code;
}

void rxrpc_process_connection(struct work_struct *work)
{
	struct rxrpc_connection *conn =
		container_of(work, struct rxrpc_connection, processor);
	struct rxrpc_skb_priv *sp;
	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))) {
		sp = rxrpc_skb(skb);

		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;
}

static int none_verify_response(struct rxrpc_connection *conn,
				struct sk_buff *skb,
				u32 *_abort_code)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
			      tracepoint_string("resp_none"));
	return -EPROTO;
}

/**
 * rxrpc_kernel_data_delivered - Record delivery of data message
 * @skb: Message holding data
 *
 * Record the delivery of a data message.  This permits RxRPC to keep its
 * tracking correct.  The socket buffer will be deleted.
 */
void rxrpc_kernel_data_delivered(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct rxrpc_call *call = sp->call;

	ASSERTCMP(ntohl(sp->hdr.seq), >=, call->rx_data_recv);
	ASSERTCMP(ntohl(sp->hdr.seq), <=, call->rx_data_recv + 1);
	call->rx_data_recv = ntohl(sp->hdr.seq);

	ASSERTCMP(ntohl(sp->hdr.seq), >, call->rx_data_eaten);
	rxrpc_free_skb(skb);
}

/*
 * reject packets through the local endpoint
 */
void rxrpc_reject_packets(struct rxrpc_local *local)
{
	struct sockaddr_rxrpc srx;
	struct rxrpc_skb_priv *sp;
	struct rxrpc_wire_header whdr;
	struct sk_buff *skb;
	struct msghdr msg;
	struct kvec iov[2];
	size_t size;
	__be32 code;

	_enter("%d", local->debug_id);

	iov[0].iov_base = &whdr;
	iov[0].iov_len = sizeof(whdr);
	iov[1].iov_base = &code;
	iov[1].iov_len = sizeof(code);
	size = sizeof(whdr) + sizeof(code);

	msg.msg_name = &srx.transport;
	msg.msg_control = NULL;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	memset(&whdr, 0, sizeof(whdr));
	whdr.type = RXRPC_PACKET_TYPE_ABORT;

	while ((skb = skb_dequeue(&local->reject_queue))) {
		rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
		sp = rxrpc_skb(skb);

		if (rxrpc_extract_addr_from_skb(&srx, skb) == 0) {
			msg.msg_namelen = srx.transport_len;

			code = htonl(skb->priority);

			whdr.epoch	= htonl(sp->hdr.epoch);
			whdr.cid	= htonl(sp->hdr.cid);
			whdr.callNumber	= htonl(sp->hdr.callNumber);
			whdr.serviceId	= htons(sp->hdr.serviceId);
			whdr.flags	= sp->hdr.flags;
			whdr.flags	^= RXRPC_CLIENT_INITIATED;
			whdr.flags	&= RXRPC_CLIENT_INITIATED;

			kernel_sendmsg(local->socket, &msg, iov, 2, size);
		}

		rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
	}

	_leave("");
}

/**
 * rxrpc_kernel_get_abort_code - Get the abort code from an RxRPC abort message
 * @skb: Message indicating an abort
 *
 * Get the abort code from an RxRPC abort message.
 */
u32 rxrpc_kernel_get_abort_code(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	switch (skb->mark) {
	case RXRPC_SKB_MARK_REMOTE_ABORT:
		return sp->call->remote_abort;
	case RXRPC_SKB_MARK_LOCAL_ABORT:
		return sp->call->local_abort;
	default:
		BUG();
	}
}

/*
 * Reply to a version request
 */
static void rxrpc_send_version_request(struct rxrpc_local *local,
				       struct rxrpc_host_header *hdr,
				       struct sk_buff *skb)
{
	struct rxrpc_wire_header whdr;
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct sockaddr_rxrpc srx;
	struct msghdr msg;
	struct kvec iov[2];
	size_t len;
	int ret;

	_enter("");

	if (rxrpc_extract_addr_from_skb(local, &srx, skb) < 0)
		return;

	msg.msg_name	= &srx.transport;
	msg.msg_namelen	= srx.transport_len;
	msg.msg_control	= NULL;
	msg.msg_controllen = 0;
	msg.msg_flags	= 0;

	whdr.epoch	= htonl(sp->hdr.epoch);
	whdr.cid	= htonl(sp->hdr.cid);
	whdr.callNumber	= htonl(sp->hdr.callNumber);
	whdr.seq	= 0;
	whdr.serial	= 0;
	whdr.type	= RXRPC_PACKET_TYPE_VERSION;
	whdr.flags	= RXRPC_LAST_PACKET | (~hdr->flags & RXRPC_CLIENT_INITIATED);
	whdr.userStatus	= 0;
	whdr.securityIndex = 0;
	whdr._rsvd	= 0;
	whdr.serviceId	= htons(sp->hdr.serviceId);

	iov[0].iov_base	= &whdr;
	iov[0].iov_len	= sizeof(whdr);
	iov[1].iov_base	= (char *)rxrpc_version_string;
	iov[1].iov_len	= sizeof(rxrpc_version_string);

	len = iov[0].iov_len + iov[1].iov_len;

	_proto("Tx VERSION (reply)");

	ret = kernel_sendmsg(local->socket, &msg, iov, 2, len);
	if (ret < 0)
		trace_rxrpc_tx_fail(local->debug_id, 0, ret,
				    rxrpc_tx_fail_version_reply);

	_leave("");
}

/*
 * Set up an incoming connection.  This is called in BH context with the RCU
 * read lock held.
 */
void rxrpc_new_incoming_connection(struct rxrpc_connection *conn,
				   struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	_enter("");

	conn->proto.epoch	= sp->hdr.epoch;
	conn->proto.cid		= sp->hdr.cid & RXRPC_CIDMASK;
	conn->params.service_id	= sp->hdr.serviceId;
	conn->security_ix	= sp->hdr.securityIndex;
	conn->out_clientflag	= 0;
	if (conn->security_ix)
		conn->state	= RXRPC_CONN_SERVICE_UNSECURED;
	else
		conn->state	= RXRPC_CONN_SERVICE;

	/* Make the connection a target for incoming packets. */
	rxrpc_publish_service_conn(conn->params.peer, conn);

	_net("CONNECTION new %d {%x}", conn->debug_id, conn->proto.cid);
}

/*
 * Find a service connection under RCU conditions.
 *
 * We could use a hash table, but that is subject to bucket stuffing by an
 * attacker as the client gets to pick the epoch and cid values and would know
 * the hash function.  So, instead, we use a hash table for the peer and from
 * that an rbtree to find the service connection.  Under ordinary circumstances
 * it might be slower than a large hash table, but it is at least limited in
 * depth.
 */
struct rxrpc_connection *rxrpc_find_service_conn_rcu(struct rxrpc_peer *peer,
						     struct sk_buff *skb)
{
	struct rxrpc_connection *conn = NULL;
	struct rxrpc_conn_proto k;
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct rb_node *p;
	unsigned int seq = 0;

	k.epoch	= sp->hdr.epoch;
	k.cid	= sp->hdr.cid & RXRPC_CIDMASK;

	do {
		/* Unfortunately, rbtree walking doesn't give reliable results
		 * under just the RCU read lock, so we have to check for
		 * changes.
		 */
		read_seqbegin_or_lock(&peer->service_conn_lock, &seq);

		p = rcu_dereference_raw(peer->service_conns.rb_node);
		while (p) {
			conn = rb_entry(p, struct rxrpc_connection, service_node);

			if (conn->proto.index_key < k.index_key)
				p = rcu_dereference_raw(p->rb_left);
			else if (conn->proto.index_key > k.index_key)
				p = rcu_dereference_raw(p->rb_right);
			else
				goto done;
			conn = NULL;
		}
	} while (need_seqretry(&peer->service_conn_lock, seq));

done:
	done_seqretry(&peer->service_conn_lock, seq);
	_leave(" = %d", conn ? conn->debug_id : -1);
	return conn;
}

/**
 * rxrpc_kernel_get_error - Get the error number from an RxRPC error message
 * @skb: Message indicating an error
 *
 * Get the error number from an RxRPC error message.
 */
int rxrpc_kernel_get_error_number(struct sk_buff *skb)
{
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);

	return sp->error;
}

/*
 * send a packet through the transport endpoint
 */
int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,
			   bool retrans)
{
	struct rxrpc_connection *conn = call->conn;
	struct rxrpc_wire_header whdr;
	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
	struct msghdr msg;
	struct kvec iov[2];
	rxrpc_serial_t serial;
	size_t len;
	bool lost = false;
	int ret, opt;

	_enter(",{%d}", skb->len);

	/* Each transmission of a Tx packet needs a new serial number */
	serial = atomic_inc_return(&conn->serial);

	whdr.epoch	= htonl(conn->proto.epoch);
	whdr.cid	= htonl(call->cid);
	whdr.callNumber	= htonl(call->call_id);
	whdr.seq	= htonl(sp->hdr.seq);
	whdr.serial	= htonl(serial);
	whdr.type	= RXRPC_PACKET_TYPE_DATA;
	whdr.flags	= sp->hdr.flags;
	whdr.userStatus	= 0;
	whdr.securityIndex = call->security_ix;
	whdr._rsvd	= htons(sp->hdr._rsvd);
	whdr.serviceId	= htons(call->service_id);

	iov[0].iov_base = &whdr;
	iov[0].iov_len = sizeof(whdr);
	iov[1].iov_base = skb->head;
	iov[1].iov_len = skb->len;
	len = iov[0].iov_len + iov[1].iov_len;

	msg.msg_name = &call->peer->srx.transport;
	msg.msg_namelen = call->peer->srx.transport_len;
	msg.msg_control = NULL;
	msg.msg_controllen = 0;
	msg.msg_flags = 0;

	/* If our RTT cache needs working on, request an ACK.  Also request
	 * ACKs if a DATA packet appears to have been lost.
	 */
	if (!(sp->hdr.flags & RXRPC_LAST_PACKET) &&
	    (retrans ||
	     call->cong_mode == RXRPC_CALL_SLOW_START ||
	     (call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
	     ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
			  ktime_get_real())))
		whdr.flags |= RXRPC_REQUEST_ACK;

	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
		static int lose;
		if ((lose++ & 7) == 7) {
			ret = 0;
			lost = true;
			goto done;
		}
	}

	_proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);

	/* send the packet with the don't fragment bit set if we currently
	 * think it's small enough */
	if (iov[1].iov_len >= call->peer->maxdata)
		goto send_fragmentable;

	down_read(&conn->params.local->defrag_sem);
	/* send the packet by UDP
	 * - returns -EMSGSIZE if UDP would have to fragment the packet
	 *   to go out of the interface
	 *   - in which case, we'll have processed the ICMP error
	 *     message and update the peer record
	 */
	ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);

	up_read(&conn->params.local->defrag_sem);
	if (ret == -EMSGSIZE)
		goto send_fragmentable;

done:
	trace_rxrpc_tx_data(call, sp->hdr.seq, serial, whdr.flags,
			    retrans, lost);
	if (ret >= 0) {
		ktime_t now = ktime_get_real();
		skb->tstamp = now;
		smp_wmb();
		sp->hdr.serial = serial;
		if (whdr.flags & RXRPC_REQUEST_ACK) {
			call->peer->rtt_last_req = now;
			trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
		}
	}
	_leave(" = %d [%u]", ret, call->peer->maxdata);
	return ret;
//.........这里部分代码省略.........

/*
 * 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 wtmp;
	u32 abort_code;
	int loop, ret;

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

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

	switch (sp->hdr.type) {
	case RXRPC_PACKET_TYPE_DATA:
	case RXRPC_PACKET_TYPE_ACK:
		rxrpc_conn_retransmit_call(conn, skb,
					   sp->hdr.cid & RXRPC_CHANNELMASK);
		return 0;

	case RXRPC_PACKET_TYPE_BUSY:
		/* Just ignore BUSY packets for now. */
		return 0;

	case RXRPC_PACKET_TYPE_ABORT:
		if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
				  &wtmp, sizeof(wtmp)) < 0) {
			trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
					      tracepoint_string("bad_abort"));
			return -EPROTO;
		}
		abort_code = ntohl(wtmp);
		_proto("Rx ABORT %%%u { ac=%d }", sp->hdr.serial, abort_code);

		conn->state = RXRPC_CONN_REMOTELY_ABORTED;
		rxrpc_abort_calls(conn, RXRPC_CALL_REMOTELY_ABORTED,
				  abort_code, -ECONNABORTED);
		return -ECONNABORTED;

	case RXRPC_PACKET_TYPE_CHALLENGE:
		return conn->security->respond_to_challenge(conn, skb,
							    _abort_code);

	case RXRPC_PACKET_TYPE_RESPONSE:
		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;

		ret = conn->security->prime_packet_security(conn);
		if (ret < 0)
			return ret;

		spin_lock(&conn->channel_lock);
		spin_lock(&conn->state_lock);

		if (conn->state == RXRPC_CONN_SERVICE_CHALLENGING) {
			conn->state = RXRPC_CONN_SERVICE;
			spin_unlock(&conn->state_lock);
			for (loop = 0; loop < RXRPC_MAXCALLS; loop++)
				rxrpc_call_is_secure(
					rcu_dereference_protected(
						conn->channels[loop].call,
						lockdep_is_held(&conn->channel_lock)));
		} else {
			spin_unlock(&conn->state_lock);
		}

		spin_unlock(&conn->channel_lock);
		return 0;

	default:
		trace_rxrpc_rx_eproto(NULL, sp->hdr.serial,
				      tracepoint_string("bad_conn_pkt"));
		return -EPROTO;
	}
}