1 files changed, 606 insertions, 0 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
new file mode 100644
index 000000000000..3322543d460a
--- /dev/null
+++ b/net/rxrpc/sendmsg.c
@@ -0,0 +1,606 @@
+/* AF_RXRPC sendmsg() implementation.
+ *
+ * Copyright (C) 2007, 2016 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 Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/net.h>
+#include <linux/gfp.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+enum rxrpc_command {
+	RXRPC_CMD_SEND_DATA,		/* send data message */
+	RXRPC_CMD_SEND_ABORT,		/* request abort generation */
+	RXRPC_CMD_ACCEPT,		/* [server] accept incoming call */
+	RXRPC_CMD_REJECT_BUSY,		/* [server] reject a call as busy */
+};
+
+/*
+ * wait for space to appear in the transmit/ACK window
+ * - caller holds the socket locked
+ */
+static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
+				    struct rxrpc_call *call,
+				    long *timeo)
+{
+	DECLARE_WAITQUEUE(myself, current);
+	int ret;
+
+	_enter(",{%u,%u,%u}",
+	       call->tx_hard_ack, call->tx_top, call->tx_winsize);
+
+	add_wait_queue(&call->waitq, &myself);
+
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		ret = 0;
+		if (call->tx_top - call->tx_hard_ack <
+		    min_t(unsigned int, call->tx_winsize,
+			  call->cong_cwnd + call->cong_extra))
+			break;
+		if (call->state >= RXRPC_CALL_COMPLETE) {
+			ret = -call->error;
+			break;
+		}
+		if (signal_pending(current)) {
+			ret = sock_intr_errno(*timeo);
+			break;
+		}
+
+		trace_rxrpc_transmit(call, rxrpc_transmit_wait);
+		release_sock(&rx->sk);
+		*timeo = schedule_timeout(*timeo);
+		lock_sock(&rx->sk);
+	}
+
+	remove_wait_queue(&call->waitq, &myself);
+	set_current_state(TASK_RUNNING);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Schedule an instant Tx resend.
+ */
+static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
+{
+	spin_lock_bh(&call->lock);
+
+	if (call->state < RXRPC_CALL_COMPLETE) {
+		call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
+		if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
+			rxrpc_queue_call(call);
+	}
+
+	spin_unlock_bh(&call->lock);
+}
+
+/*
+ * Queue a DATA packet for transmission, set the resend timeout and send the
+ * packet immediately
+ */
+static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
+			       bool last)
+{
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	rxrpc_seq_t seq = sp->hdr.seq;
+	int ret, ix;
+	u8 annotation = RXRPC_TX_ANNO_UNACK;
+
+	_net("queue skb %p [%d]", skb, seq);
+
+	ASSERTCMP(seq, ==, call->tx_top + 1);
+
+	if (last)
+		annotation |= RXRPC_TX_ANNO_LAST;
+
+	/* We have to set the timestamp before queueing as the retransmit
+	 * algorithm can see the packet as soon as we queue it.
+	 */
+	skb->tstamp = ktime_get_real();
+
+	ix = seq & RXRPC_RXTX_BUFF_MASK;
+	rxrpc_get_skb(skb, rxrpc_skb_tx_got);
+	call->rxtx_annotations[ix] = annotation;
+	smp_wmb();
+	call->rxtx_buffer[ix] = skb;
+	call->tx_top = seq;
+	if (last)
+		trace_rxrpc_transmit(call, rxrpc_transmit_queue_last);
+	else
+		trace_rxrpc_transmit(call, rxrpc_transmit_queue);
+
+	if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
+		_debug("________awaiting reply/ACK__________");
+		write_lock_bh(&call->state_lock);
+		switch (call->state) {
+		case RXRPC_CALL_CLIENT_SEND_REQUEST:
+			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
+			break;
+		case RXRPC_CALL_SERVER_ACK_REQUEST:
+			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
+			if (!last)
+				break;
+		case RXRPC_CALL_SERVER_SEND_REPLY:
+			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
+			break;
+		default:
+			break;
+		}
+		write_unlock_bh(&call->state_lock);
+	}
+
+	if (seq == 1 && rxrpc_is_client_call(call))
+		rxrpc_expose_client_call(call);
+
+	ret = rxrpc_send_data_packet(call, skb, false);
+	if (ret < 0) {
+		_debug("need instant resend %d", ret);
+		rxrpc_instant_resend(call, ix);
+	} else {
+		ktime_t now = ktime_get_real(), resend_at;
+
+		resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
+
+		if (ktime_before(resend_at, call->resend_at)) {
+			call->resend_at = resend_at;
+			rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
+		}
+	}
+
+	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	_leave("");
+}
+
+/*
+ * send data through a socket
+ * - must be called in process context
+ * - caller holds the socket locked
+ */
+static int rxrpc_send_data(struct rxrpc_sock *rx,
+			   struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len)
+{
+	struct rxrpc_skb_priv *sp;
+	struct sk_buff *skb;
+	struct sock *sk = &rx->sk;
+	long timeo;
+	bool more;
+	int ret, copied;
+
+	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+
+	/* this should be in poll */
+	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+	if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
+		return -EPIPE;
+
+	more = msg->msg_flags & MSG_MORE;
+
+	skb = call->tx_pending;
+	call->tx_pending = NULL;
+	rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
+
+	copied = 0;
+	do {
+		/* Check to see if there's a ping ACK to reply to. */
+		if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
+			rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+
+		if (!skb) {
+			size_t size, chunk, max, space;
+
+			_debug("alloc");
+
+			if (call->tx_top - call->tx_hard_ack >=
+			    min_t(unsigned int, call->tx_winsize,
+				  call->cong_cwnd + call->cong_extra)) {
+				ret = -EAGAIN;
+				if (msg->msg_flags & MSG_DONTWAIT)
+					goto maybe_error;
+				ret = rxrpc_wait_for_tx_window(rx, call,
+							       &timeo);
+				if (ret < 0)
+					goto maybe_error;
+			}
+
+			max = RXRPC_JUMBO_DATALEN;
+			max -= call->conn->security_size;
+			max &= ~(call->conn->size_align - 1UL);
+
+			chunk = max;
+			if (chunk > msg_data_left(msg) && !more)
+				chunk = msg_data_left(msg);
+
+			space = chunk + call->conn->size_align;
+			space &= ~(call->conn->size_align - 1UL);
+
+			size = space + call->conn->security_size;
+
+			_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
+
+			/* create a buffer that we can retain until it's ACK'd */
+			skb = sock_alloc_send_skb(
+				sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
+			if (!skb)
+				goto maybe_error;
+
+			rxrpc_new_skb(skb, rxrpc_skb_tx_new);
+
+			_debug("ALLOC SEND %p", skb);
+
+			ASSERTCMP(skb->mark, ==, 0);
+
+			_debug("HS: %u", call->conn->security_size);
+			skb_reserve(skb, call->conn->security_size);
+			skb->len += call->conn->security_size;
+
+			sp = rxrpc_skb(skb);
+			sp->remain = chunk;
+			if (sp->remain > skb_tailroom(skb))
+				sp->remain = skb_tailroom(skb);
+
+			_net("skb: hr %d, tr %d, hl %d, rm %d",
+			       skb_headroom(skb),
+			       skb_tailroom(skb),
+			       skb_headlen(skb),
+			       sp->remain);
+
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+		}
+
+		_debug("append");
+		sp = rxrpc_skb(skb);
+
+		/* append next segment of data to the current buffer */
+		if (msg_data_left(msg) > 0) {
+			int copy = skb_tailroom(skb);
+			ASSERTCMP(copy, >, 0);
+			if (copy > msg_data_left(msg))
+				copy = msg_data_left(msg);
+			if (copy > sp->remain)
+				copy = sp->remain;
+
+			_debug("add");
+			ret = skb_add_data(skb, &msg->msg_iter, copy);
+			_debug("added");
+			if (ret < 0)
+				goto efault;
+			sp->remain -= copy;
+			skb->mark += copy;
+			copied += copy;
+		}
+
+		/* check for the far side aborting the call or a network error
+		 * occurring */
+		if (call->state == RXRPC_CALL_COMPLETE)
+			goto call_terminated;
+
+		/* add the packet to the send queue if it's now full */
+		if (sp->remain <= 0 ||
+		    (msg_data_left(msg) == 0 && !more)) {
+			struct rxrpc_connection *conn = call->conn;
+			uint32_t seq;
+			size_t pad;
+
+			/* pad out if we're using security */
+			if (conn->security_ix) {
+				pad = conn->security_size + skb->mark;
+				pad = conn->size_align - pad;
+				pad &= conn->size_align - 1;
+				_debug("pad %zu", pad);
+				if (pad)
+					memset(skb_put(skb, pad), 0, pad);
+			}
+
+			seq = call->tx_top + 1;
+
+			sp->hdr.seq	= seq;
+			sp->hdr._rsvd	= 0;
+			sp->hdr.flags	= conn->out_clientflag;
+
+			if (msg_data_left(msg) == 0 && !more)
+				sp->hdr.flags |= RXRPC_LAST_PACKET;
+			else if (call->tx_top - call->tx_hard_ack <
+				 call->tx_winsize)
+				sp->hdr.flags |= RXRPC_MORE_PACKETS;
+
+			ret = conn->security->secure_packet(
+				call, skb, skb->mark, skb->head);
+			if (ret < 0)
+				goto out;
+
+			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
+			skb = NULL;
+		}
+	} while (msg_data_left(msg) > 0);
+
+success:
+	ret = copied;
+out:
+	call->tx_pending = skb;
+	_leave(" = %d", ret);
+	return ret;
+
+call_terminated:
+	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	_leave(" = %d", -call->error);
+	return -call->error;
+
+maybe_error:
+	if (copied)
+		goto success;
+	goto out;
+
+efault:
+	ret = -EFAULT;
+	goto out;
+}
+
+/*
+ * extract control messages from the sendmsg() control buffer
+ */
+static int rxrpc_sendmsg_cmsg(struct msghdr *msg,
+			      unsigned long *user_call_ID,
+			      enum rxrpc_command *command,
+			      u32 *abort_code,
+			      bool *_exclusive)
+{
+	struct cmsghdr *cmsg;
+	bool got_user_ID = false;
+	int len;
+
+	*command = RXRPC_CMD_SEND_DATA;
+
+	if (msg->msg_controllen == 0)
+		return -EINVAL;
+
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg))
+			return -EINVAL;
+
+		len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
+		_debug("CMSG %d, %d, %d",
+		       cmsg->cmsg_level, cmsg->cmsg_type, len);
+
+		if (cmsg->cmsg_level != SOL_RXRPC)
+			continue;
+
+		switch (cmsg->cmsg_type) {
+		case RXRPC_USER_CALL_ID:
+			if (msg->msg_flags & MSG_CMSG_COMPAT) {
+				if (len != sizeof(u32))
+					return -EINVAL;
+				*user_call_ID = *(u32 *) CMSG_DATA(cmsg);
+			} else {
+				if (len != sizeof(unsigned long))
+					return -EINVAL;
+				*user_call_ID = *(unsigned long *)
+					CMSG_DATA(cmsg);
+			}
+			_debug("User Call ID %lx", *user_call_ID);
+			got_user_ID = true;
+			break;
+
+		case RXRPC_ABORT:
+			if (*command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			*command = RXRPC_CMD_SEND_ABORT;
+			if (len != sizeof(*abort_code))
+				return -EINVAL;
+			*abort_code = *(unsigned int *) CMSG_DATA(cmsg);
+			_debug("Abort %x", *abort_code);
+			if (*abort_code == 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_ACCEPT:
+			if (*command != RXRPC_CMD_SEND_DATA)
+				return -EINVAL;
+			*command = RXRPC_CMD_ACCEPT;
+			if (len != 0)
+				return -EINVAL;
+			break;
+
+		case RXRPC_EXCLUSIVE_CALL:
+			*_exclusive = true;
+			if (len != 0)
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	if (!got_user_ID)
+		return -EINVAL;
+	_leave(" = 0");
+	return 0;
+}
+
+/*
+ * Create a new client call for sendmsg().
+ */
+static struct rxrpc_call *
+rxrpc_new_client_call_for_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg,
+				  unsigned long user_call_ID, bool exclusive)
+{
+	struct rxrpc_conn_parameters cp;
+	struct rxrpc_call *call;
+	struct key *key;
+
+	DECLARE_SOCKADDR(struct sockaddr_rxrpc *, srx, msg->msg_name);
+
+	_enter("");
+
+	if (!msg->msg_name)
+		return ERR_PTR(-EDESTADDRREQ);
+
+	key = rx->key;
+	if (key && !rx->key->payload.data[0])
+		key = NULL;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.local		= rx->local;
+	cp.key			= rx->key;
+	cp.security_level	= rx->min_sec_level;
+	cp.exclusive		= rx->exclusive | exclusive;
+	cp.service_id		= srx->srx_service;
+	call = rxrpc_new_client_call(rx, &cp, srx, user_call_ID, GFP_KERNEL);
+
+	_leave(" = %p\n", call);
+	return call;
+}
+
+/*
+ * send a message forming part of a client call through an RxRPC socket
+ * - caller holds the socket locked
+ * - the socket may be either a client socket or a server socket
+ */
+int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
+{
+	enum rxrpc_command cmd;
+	struct rxrpc_call *call;
+	unsigned long user_call_ID = 0;
+	bool exclusive = false;
+	u32 abort_code = 0;
+	int ret;
+
+	_enter("");
+
+	ret = rxrpc_sendmsg_cmsg(msg, &user_call_ID, &cmd, &abort_code,
+				 &exclusive);
+	if (ret < 0)
+		return ret;
+
+	if (cmd == RXRPC_CMD_ACCEPT) {
+		if (rx->sk.sk_state != RXRPC_SERVER_LISTENING)
+			return -EINVAL;
+		call = rxrpc_accept_call(rx, user_call_ID, NULL);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+		rxrpc_put_call(call, rxrpc_call_put);
+		return 0;
+	}
+
+	call = rxrpc_find_call_by_user_ID(rx, user_call_ID);
+	if (!call) {
+		if (cmd != RXRPC_CMD_SEND_DATA)
+			return -EBADSLT;
+		call = rxrpc_new_client_call_for_sendmsg(rx, msg, user_call_ID,
+							 exclusive);
+		if (IS_ERR(call))
+			return PTR_ERR(call);
+	}
+
+	_debug("CALL %d USR %lx ST %d on CONN %p",
+	       call->debug_id, call->user_call_ID, call->state, call->conn);
+
+	if (call->state >= RXRPC_CALL_COMPLETE) {
+		/* it's too late for this call */
+		ret = -ESHUTDOWN;
+	} else if (cmd == RXRPC_CMD_SEND_ABORT) {
+		ret = 0;
+		if (rxrpc_abort_call("CMD", call, 0, abort_code, ECONNABORTED))
+			ret = rxrpc_send_call_packet(call,
+						     RXRPC_PACKET_TYPE_ABORT);
+	} else if (cmd != RXRPC_CMD_SEND_DATA) {
+		ret = -EINVAL;
+	} else if (rxrpc_is_client_call(call) &&
+		   call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
+		/* request phase complete for this client call */
+		ret = -EPROTO;
+	} else if (rxrpc_is_service_call(call) &&
+		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		/* Reply phase not begun or not complete for service call. */
+		ret = -EPROTO;
+	} else {
+		ret = rxrpc_send_data(rx, call, msg, len);
+	}
+
+	rxrpc_put_call(call, rxrpc_call_put);
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/**
+ * rxrpc_kernel_send_data - Allow a kernel service to send data on a call
+ * @sock: The socket the call is on
+ * @call: The call to send data through
+ * @msg: The data to send
+ * @len: The amount of data to send
+ *
+ * Allow a kernel service to send data on a call.  The call must be in an state
+ * appropriate to sending data.  No control data should be supplied in @msg,
+ * nor should an address be supplied.  MSG_MORE should be flagged if there's
+ * more data to come, otherwise this data will end the transmission phase.
+ */
+int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len)
+{
+	int ret;
+
+	_enter("{%d,%s},", call->debug_id, rxrpc_call_states[call->state]);
+
+	ASSERTCMP(msg->msg_name, ==, NULL);
+	ASSERTCMP(msg->msg_control, ==, NULL);
+
+	lock_sock(sock->sk);
+
+	_debug("CALL %d USR %lx ST %d on CONN %p",
+	       call->debug_id, call->user_call_ID, call->state, call->conn);
+
+	if (call->state >= RXRPC_CALL_COMPLETE) {
+		ret = -ESHUTDOWN; /* it's too late for this call */
+	} else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
+		   call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
+		ret = -EPROTO; /* request phase complete for this client call */
+	} else {
+		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
+	}
+
+	release_sock(sock->sk);
+	_leave(" = %d", ret);
+	return ret;
+}
+EXPORT_SYMBOL(rxrpc_kernel_send_data);
+
+/**
+ * rxrpc_kernel_abort_call - Allow a kernel service to abort a call
+ * @sock: The socket the call is on
+ * @call: The call to be aborted
+ * @abort_code: The abort code to stick into the ABORT packet
+ * @error: Local error value
+ * @why: 3-char string indicating why.
+ *
+ * Allow a kernel service to abort a call, if it's still in an abortable state.
+ */
+void rxrpc_kernel_abort_call(struct socket *sock, struct rxrpc_call *call,
+			     u32 abort_code, int error, const char *why)
+{
+	_enter("{%d},%d,%d,%s", call->debug_id, abort_code, error, why);
+
+	lock_sock(sock->sk);
+
+	if (rxrpc_abort_call(why, call, 0, abort_code, error))
+		rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ABORT);
+
+	release_sock(sock->sk);
+	_leave("");
+}
+
+EXPORT_SYMBOL(rxrpc_kernel_abort_call);