rxrpc: Split sendmsg from packet transmission code

Split the sendmsg code from the packet transmission code (mostly to be
found in output.c).

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 645 insertions, 0 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
new file mode 100644
index 000000000000..ff3e28ddc6d8
--- /dev/null
+++ b/net/rxrpc/sendmsg.c
@@ -0,0 +1,645 @@
+/* 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 <linux/circ_buf.h>
+#include <net/sock.h>
+#include <net/af_rxrpc.h>
+#include "ar-internal.h"
+
+static int rxrpc_send_data(struct rxrpc_sock *rx,
+			   struct rxrpc_call *call,
+			   struct msghdr *msg, size_t len);
+
+/*
+ * 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;
+}
+
+/*
+ * abort a call, sending an ABORT packet to the peer
+ */
+static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
+{
+	if (call->state >= RXRPC_CALL_COMPLETE)
+		return;
+
+	write_lock_bh(&call->state_lock);
+
+	if (__rxrpc_abort_call(call, abort_code, ECONNABORTED)) {
+		del_timer_sync(&call->resend_timer);
+		del_timer_sync(&call->ack_timer);
+		clear_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events);
+		clear_bit(RXRPC_CALL_EV_ACK, &call->events);
+		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
+		rxrpc_queue_call(call);
+	}
+
+	write_unlock_bh(&call->state_lock);
+}
+
+/*
+ * 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);
+		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);
+	}
+
+	rxrpc_see_call(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) {
+		rxrpc_send_abort(call, abort_code);
+		ret = 0;
+	} 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);
+	_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
+ *
+ * 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)
+{
+	_enter("{%d},%d", call->debug_id, abort_code);
+
+	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);
+
+	rxrpc_send_abort(call, abort_code);
+
+	release_sock(sock->sk);
+	_leave("");
+}
+
+EXPORT_SYMBOL(rxrpc_kernel_abort_call);
+
+/*
+ * 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(",{%d},%ld",
+	       CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
+			  call->acks_winsz),
+	       *timeo);
+
+	add_wait_queue(&call->waitq, &myself);
+
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		ret = 0;
+		if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
+			       call->acks_winsz) > 0)
+			break;
+		if (signal_pending(current)) {
+			ret = sock_intr_errno(*timeo);
+			break;
+		}
+
+		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;
+}
+
+/*
+ * attempt to schedule an instant Tx resend
+ */
+static inline void rxrpc_instant_resend(struct rxrpc_call *call)
+{
+	read_lock_bh(&call->state_lock);
+	if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
+		clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
+		if (call->state < RXRPC_CALL_COMPLETE &&
+		    !test_and_set_bit(RXRPC_CALL_EV_RESEND_TIMER, &call->events))
+			rxrpc_queue_call(call);
+	}
+	read_unlock_bh(&call->state_lock);
+}
+
+/*
+ * queue a packet for transmission, set the resend timer and attempt
+ * to 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);
+	int ret;
+
+	_net("queue skb %p [%d]", skb, call->acks_head);
+
+	ASSERT(call->acks_window != NULL);
+	call->acks_window[call->acks_head] = (unsigned long) skb;
+	smp_wmb();
+	call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
+
+	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);
+	}
+
+	_proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
+
+	sp->need_resend = false;
+	sp->resend_at = jiffies + rxrpc_resend_timeout;
+	if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
+		_debug("run timer");
+		call->resend_timer.expires = sp->resend_at;
+		add_timer(&call->resend_timer);
+	}
+
+	/* attempt to cancel the rx-ACK timer, deferring reply transmission if
+	 * we're ACK'ing the request phase of an incoming call */
+	ret = -EAGAIN;
+	if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
+		/* the packet may be freed by rxrpc_process_call() before this
+		 * returns */
+		if (rxrpc_is_client_call(call))
+			rxrpc_expose_client_call(call);
+		ret = rxrpc_send_data_packet(call->conn, skb);
+		_net("sent skb %p", skb);
+	} else {
+		_debug("failed to delete ACK timer");
+	}
+
+	if (ret < 0) {
+		_debug("need instant resend %d", ret);
+		sp->need_resend = true;
+		rxrpc_instant_resend(call);
+	}
+
+	_leave("");
+}
+
+/*
+ * Convert a host-endian header into a network-endian header.
+ */
+static void rxrpc_insert_header(struct sk_buff *skb)
+{
+	struct rxrpc_wire_header whdr;
+	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+	whdr.epoch	= htonl(sp->hdr.epoch);
+	whdr.cid	= htonl(sp->hdr.cid);
+	whdr.callNumber	= htonl(sp->hdr.callNumber);
+	whdr.seq	= htonl(sp->hdr.seq);
+	whdr.serial	= htonl(sp->hdr.serial);
+	whdr.type	= sp->hdr.type;
+	whdr.flags	= sp->hdr.flags;
+	whdr.userStatus	= sp->hdr.userStatus;
+	whdr.securityIndex = sp->hdr.securityIndex;
+	whdr._rsvd	= htons(sp->hdr._rsvd);
+	whdr.serviceId	= htons(sp->hdr.serviceId);
+
+	memcpy(skb->head, &whdr, sizeof(whdr));
+}
+
+/*
+ * 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);
+
+	copied = 0;
+	do {
+		if (!skb) {
+			size_t size, chunk, max, space;
+
+			_debug("alloc");
+
+			if (CIRC_SPACE(call->acks_head,
+				       ACCESS_ONCE(call->acks_tail),
+				       call->acks_winsz) <= 0) {
+				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 = call->conn->params.peer->maxdata;
+			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->header_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);
+
+			_debug("ALLOC SEND %p", skb);
+
+			ASSERTCMP(skb->mark, ==, 0);
+
+			_debug("HS: %u", call->conn->header_size);
+			skb_reserve(skb, call->conn->header_size);
+			skb->len += call->conn->header_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 = atomic_inc_return(&call->sequence);
+
+			sp->hdr.epoch	= conn->proto.epoch;
+			sp->hdr.cid	= call->cid;
+			sp->hdr.callNumber = call->call_id;
+			sp->hdr.seq	= seq;
+			sp->hdr.serial	= atomic_inc_return(&conn->serial);
+			sp->hdr.type	= RXRPC_PACKET_TYPE_DATA;
+			sp->hdr.userStatus = 0;
+			sp->hdr.securityIndex = conn->security_ix;
+			sp->hdr._rsvd	= 0;
+			sp->hdr.serviceId = call->service_id;
+
+			sp->hdr.flags = conn->out_clientflag;
+			if (msg_data_left(msg) == 0 && !more)
+				sp->hdr.flags |= RXRPC_LAST_PACKET;
+			else if (CIRC_SPACE(call->acks_head,
+					    ACCESS_ONCE(call->acks_tail),
+					    call->acks_winsz) > 1)
+				sp->hdr.flags |= RXRPC_MORE_PACKETS;
+			if (more && seq & 1)
+				sp->hdr.flags |= RXRPC_REQUEST_ACK;
+
+			ret = conn->security->secure_packet(
+				call, skb, skb->mark,
+				skb->head + sizeof(struct rxrpc_wire_header));
+			if (ret < 0)
+				goto out;
+
+			rxrpc_insert_header(skb);
+			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);
+	_leave(" = %d", -call->error);
+	return ret;
+
+maybe_error:
+	if (copied)
+		goto success;
+	goto out;
+
+efault:
+	ret = -EFAULT;
+	goto out;
+}