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nuttx/net/udp/udp_sendto_buffered.c
chao an 8a63d29c6e net/devif_poll: optimize device buffer alloc in txpoll 
Allocate the device buffer only if the protocol really need to send data.
not all protocols require the driver to prepare additional iob before
sending, especially UDP, each iob reserves l2/l3 header in advance
after prepare write buffer, net device could reuse this entry to send directly

Signed-off-by: chao an <anchao@xiaomi.com>
2023-01-13 16:41:10 +08:00

950 lines
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/****************************************************************************
* net/udp/udp_sendto_buffered.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET) && defined(CONFIG_NET_UDP) && \
defined(CONFIG_NET_UDP_WRITE_BUFFERS)
#if defined(CONFIG_DEBUG_FEATURES) && defined(CONFIG_NET_UDP_WRBUFFER_DEBUG)
/* Force debug output (from this file only) */
# undef CONFIG_DEBUG_NET
# define CONFIG_DEBUG_NET 1
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arch/irq.h>
#include <nuttx/net/net.h>
#include <nuttx/mm/iob.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/udp.h>
#include "netdev/netdev.h"
#include "socket/socket.h"
#include "inet/inet.h"
#include "arp/arp.h"
#include "icmpv6/icmpv6.h"
#include "neighbor/neighbor.h"
#include "udp/udp.h"
#include "devif/devif.h"
#include "utils/utils.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* If both IPv4 and IPv6 support are both enabled, then we will need to build
* in some additional domain selection support.
*/
#if defined(CONFIG_NET_IPv4) && defined(CONFIG_NET_IPv6)
# define NEED_IPDOMAIN_SUPPORT 1
#endif
/* Debug */
#ifdef CONFIG_NET_UDP_WRBUFFER_DUMP
# define BUF_DUMP(msg,buf,len) lib_dumpbuffer(msg,buf,len)
#else
# define BUF_DUMP(msg,buf,len)
# undef UDP_WBDUMP
# define UDP_WBDUMP(msg,wrb,len,offset)
#endif
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
#ifdef NEED_IPDOMAIN_SUPPORT
static inline void sendto_ipselect(FAR struct net_driver_s *dev,
FAR struct udp_conn_s *conn);
#endif
static int sendto_next_transfer(FAR struct udp_conn_s *conn);
static uint16_t sendto_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvpriv, uint16_t flags);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sendto_writebuffer_release
*
* Description:
* Release the write buffer at the head of the write buffer queue.
*
* Input Parameters:
* conn - The UDP connection of interest
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static void sendto_writebuffer_release(FAR struct udp_conn_s *conn)
{
FAR struct udp_wrbuffer_s *wrb;
int ret = OK;
do
{
/* Check if the write queue became empty */
if (sq_empty(&conn->write_q))
{
/* Yes.. stifle any further callbacks until more write data is
* enqueued.
*/
conn->sndcb->flags = 0;
conn->sndcb->priv = NULL;
conn->sndcb->event = NULL;
wrb = NULL;
#ifdef CONFIG_NET_UDP_NOTIFIER
/* Notify any waiters that the write buffers have been drained. */
udp_writebuffer_signal(conn);
#endif
}
else
{
/* Remove the write buffer from the head of the write buffer queue
* and release it.
*/
wrb = (FAR struct udp_wrbuffer_s *)sq_remfirst(&conn->write_q);
DEBUGASSERT(wrb != NULL);
/* Do not need to release wb_iob, the life cycle of wb_iob is
* handed over to the network device
*/
wrb->wb_iob = NULL;
udp_wrbuffer_release(wrb);
/* Set up for the next packet transfer by setting the connection
* address to the address of the next packet now at the header of
* the write buffer queue.
*/
ret = sendto_next_transfer(conn);
}
}
while (wrb != NULL && ret < 0);
#if CONFIG_NET_SEND_BUFSIZE > 0
/* Notify the send buffer available if wrbbuffer drained */
udp_sendbuffer_notify(conn);
#endif /* CONFIG_NET_SEND_BUFSIZE */
}
/****************************************************************************
* Name: sendto_ipselect
*
* Description:
* If both IPv4 and IPv6 support are enabled, then we will need to select
* which one to use when generating the outgoing packet. If only one
* domain is selected, then the setup is already in place and we need do
* nothing.
*
* Input Parameters:
* dev - The structure of the network driver that caused the event
* conn - The UDP connection of interest
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
#ifdef NEED_IPDOMAIN_SUPPORT
static inline void sendto_ipselect(FAR struct net_driver_s *dev,
FAR struct udp_conn_s *conn)
{
/* Which domain the socket support */
if (conn->domain == PF_INET)
{
/* Select the IPv4 domain */
udp_ipv4_select(dev);
}
else /* if (conn->domain == PF_INET6) */
{
/* Select the IPv6 domain */
udp_ipv6_select(dev);
}
}
#endif
/****************************************************************************
* Name: sendto_next_transfer
*
* Description:
* Setup for the next packet transfer. That function is called (1)
* psock_udp_sendto() by when the new UDP packet is buffered at the head of
* the write queue and (2) by sendto_writebuffer_release() when that
* previously queued write buffer was sent and a new write buffer lies at
* the head of the write queue.
*
* Input Parameters:
* conn - The UDP connection structure
*
* Returned Value:
* None
*
****************************************************************************/
static int sendto_next_transfer(FAR struct udp_conn_s *conn)
{
FAR struct udp_wrbuffer_s *wrb;
FAR struct net_driver_s *dev;
/* Set the UDP "connection" to the destination address of the write buffer
* at the head of the queue.
*/
wrb = (FAR struct udp_wrbuffer_s *)sq_peek(&conn->write_q);
if (wrb == NULL)
{
ninfo("Write buffer queue is empty\n");
return -ENOENT;
}
/* Has this address already been bound to a local port (lport)? */
if (!conn->lport)
{
/* No.. Find an unused local port number and bind it to the
* connection structure.
*/
conn->lport = HTONS(udp_select_port(conn->domain, &conn->u));
}
/* Get the device that will handle the remote packet transfers. This
* should never be NULL.
*
* REVISIT: There is a logical error here for the case where there are
* multiple network devices. In that case, the packets may need to be sent
* in a different order than they were queued. Forcing FIFO packet
* transmission could harm performance.
*/
dev = udp_find_raddr_device(conn, &wrb->wb_dest);
if (dev == NULL)
{
nerr("ERROR: udp_find_raddr_device failed\n");
return -ENETUNREACH;
}
/* Make sure that the device is in the UP state */
if ((dev->d_flags & IFF_UP) == 0)
{
nwarn("WARNING: device is DOWN\n");
return -EHOSTUNREACH;
}
/* If this is not the same device that we used in the last call to
* udp_callback_alloc(), then we need to release and reallocate the old
* callback instance.
*/
if (conn->sndcb != NULL && conn->dev != dev)
{
udp_callback_free(conn->dev, conn, conn->sndcb);
conn->sndcb = NULL;
}
/* Allocate resources to receive a callback from this device if the
* callback is not already in place.
*/
if (conn->sndcb == NULL)
{
conn->sndcb = udp_callback_alloc(dev, conn);
}
/* Test if the callback has been allocated */
if (conn->sndcb == NULL)
{
/* A buffer allocation error occurred */
nerr("ERROR: Failed to allocate callback\n");
return -ENOMEM;
}
conn->dev = dev;
/* Set up the callback in the connection */
conn->sndcb->flags = (UDP_POLL | NETDEV_DOWN);
conn->sndcb->priv = (FAR void *)conn;
conn->sndcb->event = sendto_eventhandler;
/* Notify the device driver of the availability of TX data */
netdev_txnotify_dev(dev);
return OK;
}
/****************************************************************************
* Name: sendto_eventhandler
*
* Description:
* This function is called to perform the actual send operation when
* polled by the lower, device interfacing layer.
*
* Input Parameters:
* dev The structure of the network driver that caused the event
* conn The connection structure associated with the socket
* flags Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked
*
****************************************************************************/
static uint16_t sendto_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvpriv, uint16_t flags)
{
FAR struct udp_conn_s *conn = pvpriv;
DEBUGASSERT(dev != NULL && conn != NULL);
ninfo("flags: %04x\n", flags);
/* Check if the network device has gone down */
if ((flags & NETDEV_DOWN) != 0)
{
ninfo("Device down: %04x\n", flags);
/* Free the write buffer at the head of the queue and attempt to setup
* the next transfer.
*/
sendto_writebuffer_release(conn);
return flags;
}
/* The UDP socket should be bound to a device. Make sure that the polling
* device is the one that we are bound to.
*
* REVISIT: There is a logical error here for the case where there are
* multiple network devices. In that case, the packets may need to be sent
* in a different order than they were queued. The packet we may need to
* send on this device may not be at the head of the list. Forcing FIFO
* packet transmission could degrade performance!
*/
DEBUGASSERT(conn != NULL);
DEBUGASSERT(conn->dev != NULL);
if (dev != conn->dev)
{
return flags;
}
/* Check for a normal polling cycle and if the outgoing packet is
* available. It would not be available if it has been claimed by a send
* event serving a different thread -OR- if the output buffer currently
* contains unprocessed incoming data. In these cases we will just have
* to wait for the next polling cycle.
*
* And, of course, we can do nothing if we have no data in the write
* buffers to send.
*/
if (dev->d_sndlen <= 0 && (flags & UDP_NEWDATA) == 0 &&
(flags & UDP_POLL) != 0 && !sq_empty(&conn->write_q))
{
uint16_t udpiplen = udpip_hdrsize(conn);
FAR struct udp_wrbuffer_s *wrb;
/* Peek at the head of the write queue (but don't remove anything
* from the write queue yet). We know from the above test that
* the write_q is not empty.
*/
wrb = (FAR struct udp_wrbuffer_s *)sq_peek(&conn->write_q);
DEBUGASSERT(wrb != NULL);
/* If the udp socket not connected, it is possible to have
* multi-different destination address in each iob entry,
* update the remote address every time to avoid sent to the
* incorrect destination.
*/
udp_connect(conn, (FAR const struct sockaddr *)&wrb->wb_dest);
/* Then set-up to send that amount of data with the offset
* corresponding to the size of the IP-dependent address structure.
*/
netdev_iob_replace(dev, wrb->wb_iob);
/* Get the amount of data that we can send in the next packet.
* We will send either the remaining data in the buffer I/O
* buffer chain, or as much as will fit given the MSS and current
* window size.
*/
dev->d_sndlen = wrb->wb_iob->io_pktlen - udpiplen;
ninfo("wrb=%p sndlen=%d\n", wrb, dev->d_sndlen);
#ifdef NEED_IPDOMAIN_SUPPORT
/* If both IPv4 and IPv6 support are enabled, then we will need to
* select which one to use when generating the outgoing packet.
* If only one domain is selected, then the setup is already in
* place and we need do nothing.
*/
sendto_ipselect(dev, conn);
#endif
/* Free the write buffer at the head of the queue and attempt to
* setup the next transfer.
*/
sendto_writebuffer_release(conn);
/* Only one data can be sent by low level driver at once,
* tell the caller stop polling the other connections.
*/
flags &= ~UDP_POLL;
}
/* Continue waiting */
return flags;
}
/****************************************************************************
* Name: udp_send_gettimeout
*
* Description:
* Calculate the send timeout
*
****************************************************************************/
static unsigned int udp_send_gettimeout(clock_t start, unsigned int timeout)
{
unsigned int elapse;
if (timeout != UINT_MAX)
{
elapse = TICK2MSEC(clock_systime_ticks() - start);
if (elapse >= timeout)
{
timeout = 0;
}
else
{
timeout -= elapse;
}
}
return timeout;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: psock_udp_sendto
*
* Description:
* This function implements the UDP-specific logic of the standard
* sendto() socket operation.
*
* Input Parameters:
* psock A pointer to a NuttX-specific, internal socket structure
* buf Data to send
* len Length of data to send
* flags Send flags
* to Address of recipient
* tolen The length of the address structure
*
* NOTE: All input parameters were verified by sendto() before this
* function was called.
*
* Returned Value:
* On success, returns the number of characters sent. On error,
* a negated errno value is returned. See the description in
* net/socket/sendto.c for the list of appropriate return value.
*
****************************************************************************/
ssize_t psock_udp_sendto(FAR struct socket *psock, FAR const void *buf,
size_t len, int flags,
FAR const struct sockaddr *to, socklen_t tolen)
{
FAR struct udp_wrbuffer_s *wrb;
FAR struct udp_conn_s *conn;
unsigned int timeout;
uint16_t udpiplen;
bool nonblock;
bool empty;
int ret = OK;
clock_t start;
/* Get the underlying the UDP connection structure. */
conn = psock->s_conn;
DEBUGASSERT(conn);
/* If the UDP socket was previously assigned a remote peer address via
* connect(), then as with connection-mode socket, sendto() may not be
* used with a non-NULL destination address. Normally send() would be
* used with such connected UDP sockets.
*/
if (to != NULL && _SS_ISCONNECTED(conn->sconn.s_flags))
{
/* EISCONN - A destination address was specified and the socket is
* already connected.
*/
return -EISCONN;
}
/* Otherwise, if the socket is not connected, then a destination address
* must be provided.
*/
else if (to == NULL && !_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* EDESTADDRREQ - The socket is not connection-mode and no peer
* address is set.
*/
return -EDESTADDRREQ;
}
#if defined(CONFIG_NET_ARP_SEND) || defined(CONFIG_NET_ICMPv6_NEIGHBOR)
#ifdef CONFIG_NET_ARP_SEND
/* Assure the the IPv4 destination address maps to a valid MAC address in
* the ARP table.
*/
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
if (psock->s_domain == PF_INET)
#endif
{
in_addr_t destipaddr;
/* Check if the socket is connection mode */
if (_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Yes.. use the connected remote address (the 'to' address is
* null).
*/
destipaddr = conn->u.ipv4.raddr;
}
else
{
FAR const struct sockaddr_in *into;
/* No.. use the destination address provided by the non-NULL 'to'
* argument.
*/
into = (FAR const struct sockaddr_in *)to;
destipaddr = into->sin_addr.s_addr;
}
/* Make sure that the IP address mapping is in the ARP table */
ret = arp_send(destipaddr);
}
#endif /* CONFIG_NET_ARP_SEND */
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
/* Assure the the IPv6 destination address maps to a valid MAC address in
* the neighbor table.
*/
#ifdef CONFIG_NET_ARP_SEND
else
#endif
{
FAR const uint16_t *destipaddr;
/* Check if the socket is connection mode */
if (_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Yes.. use the connected remote address (the 'to' address is
* null).
*/
destipaddr = conn->u.ipv6.raddr;
}
else
{
FAR const struct sockaddr_in6 *into;
/* No.. use the destination address provided by the non-NULL 'to'
* argument.
*/
into = (FAR const struct sockaddr_in6 *)to;
destipaddr = into->sin6_addr.s6_addr16;
}
/* Make sure that the IP address mapping is in the Neighbor Table */
ret = icmpv6_neighbor(destipaddr);
}
#endif /* CONFIG_NET_ICMPv6_NEIGHBOR */
/* Did we successfully get the address mapping? */
if (ret < 0)
{
nerr("ERROR: Not reachable\n");
return -ENETUNREACH;
}
#endif /* CONFIG_NET_ARP_SEND || CONFIG_NET_ICMPv6_NEIGHBOR */
nonblock = _SS_ISNONBLOCK(conn->sconn.s_flags) ||
(flags & MSG_DONTWAIT) != 0;
start = clock_systime_ticks();
timeout = _SO_TIMEOUT(conn->sconn.s_sndtimeo);
/* Dump the incoming buffer */
BUF_DUMP("psock_udp_sendto", buf, len);
if (len > 0)
{
net_lock();
#if CONFIG_NET_SEND_BUFSIZE > 0
/* If the send buffer size exceeds the send limit,
* wait for the write buffer to be released
*/
while (udp_wrbuffer_inqueue_size(conn) + len > conn->sndbufs)
{
if (nonblock)
{
ret = -EAGAIN;
goto errout_with_lock;
}
ret = net_timedwait_uninterruptible(&conn->sndsem,
udp_send_gettimeout(start, timeout));
if (ret < 0)
{
if (ret == -ETIMEDOUT)
{
ret = -EAGAIN;
}
goto errout_with_lock;
}
}
#endif /* CONFIG_NET_SEND_BUFSIZE */
/* Allocate a write buffer. Careful, the network will be momentarily
* unlocked here.
*/
if (nonblock)
{
wrb = udp_wrbuffer_tryalloc();
}
else
{
wrb = udp_wrbuffer_timedalloc(udp_send_gettimeout(start,
timeout));
}
if (wrb == NULL)
{
/* A buffer allocation error occurred */
nerr("ERROR: Failed to allocate write buffer\n");
if (nonblock || timeout != UINT_MAX)
{
ret = -EAGAIN;
}
else
{
ret = -ENOMEM;
}
goto errout_with_lock;
}
/* Initialize the write buffer
*
* Check if the socket is connected
*/
if (_SS_ISCONNECTED(conn->sconn.s_flags))
{
/* Yes.. get the connection address from the connection structure */
#ifdef CONFIG_NET_IPv4
#ifdef CONFIG_NET_IPv6
if (conn->domain == PF_INET)
#endif
{
FAR struct sockaddr_in *addr4 =
(FAR struct sockaddr_in *)&wrb->wb_dest;
addr4->sin_family = AF_INET;
addr4->sin_port = conn->rport;
net_ipv4addr_copy(addr4->sin_addr.s_addr, conn->u.ipv4.raddr);
memset(addr4->sin_zero, 0, sizeof(addr4->sin_zero));
}
#endif /* CONFIG_NET_IPv4 */
#ifdef CONFIG_NET_IPv6
#ifdef CONFIG_NET_IPv4
else
#endif
{
FAR struct sockaddr_in6 *addr6 =
(FAR struct sockaddr_in6 *)&wrb->wb_dest;
addr6->sin6_family = AF_INET6;
addr6->sin6_port = conn->rport;
net_ipv6addr_copy(addr6->sin6_addr.s6_addr,
conn->u.ipv6.raddr);
}
#endif /* CONFIG_NET_IPv6 */
}
/* Not connected. Use the provided destination address */
else
{
memcpy(&wrb->wb_dest, to, tolen);
}
/* Skip l2/l3/l4 offset before copy */
udpiplen = udpip_hdrsize(conn);
iob_reserve(wrb->wb_iob, CONFIG_NET_LL_GUARDSIZE);
iob_update_pktlen(wrb->wb_iob, udpiplen);
/* Copy the user data into the write buffer. We cannot wait for
* buffer space if the socket was opened non-blocking.
*/
if (nonblock)
{
ret = iob_trycopyin(wrb->wb_iob, (FAR uint8_t *)buf,
len, udpiplen, false);
}
else
{
unsigned int count;
int blresult;
/* iob_copyin might wait for buffers to be freed, but if
* network is locked this might never happen, since network
* driver is also locked, therefore we need to break the lock
*/
blresult = net_breaklock(&count);
ret = iob_copyin(wrb->wb_iob, (FAR uint8_t *)buf,
len, udpiplen, false);
if (blresult >= 0)
{
net_restorelock(count);
}
}
if (ret < 0)
{
goto errout_with_wrb;
}
/* Dump I/O buffer chain */
UDP_WBDUMP("I/O buffer chain", wrb, wrb->wb_iob->io_pktlen, 0);
/* sendto_eventhandler() will send data in FIFO order from the
* conn->write_q.
*
* REVISIT: Why FIFO order? Because it is easy. In a real world
* environment where there are multiple network devices this might
* be inefficient because we could be sending data to different
* device out-of-queued-order to optimize performance. Sending
* data to different networks from a single UDP socket is probably
* not a very common use case, however.
*/
empty = sq_empty(&conn->write_q);
sq_addlast(&wrb->wb_node, &conn->write_q);
ninfo("Queued WRB=%p pktlen=%u write_q(%p,%p)\n",
wrb, wrb->wb_iob->io_pktlen,
conn->write_q.head, conn->write_q.tail);
if (empty)
{
/* The new write buffer lies at the head of the write queue. Set
* up for the next packet transfer by setting the connection
* address to the address of the next packet now at the header of
* the write buffer queue.
*/
ret = sendto_next_transfer(conn);
if (ret < 0)
{
sq_remlast(&conn->write_q);
goto errout_with_wrb;
}
}
net_unlock();
}
/* Return the number of bytes that will be sent */
return len;
errout_with_wrb:
udp_wrbuffer_release(wrb);
errout_with_lock:
net_unlock();
return ret;
}
/****************************************************************************
* Name: psock_udp_cansend
*
* Description:
* psock_udp_cansend() returns a value indicating if a write to the socket
* would block. No space in the buffer is actually reserved, so it is
* possible that the write may still block if the buffer is filled by
* another means.
*
* Input Parameters:
* conn A reference to UDP connection structure.
*
* Returned Value:
* OK
* At least one byte of data could be successfully written.
* -EWOULDBLOCK
* There is no room in the output buffer.
* -EBADF
* An invalid descriptor was specified.
*
****************************************************************************/
int psock_udp_cansend(FAR struct udp_conn_s *conn)
{
/* Verify that we received a valid socket */
if (conn == NULL)
{
nerr("ERROR: Invalid socket\n");
return -EBADF;
}
/* In order to setup the send, we need to have at least one free write
* buffer head and at least one free IOB to initialize the write buffer
* head.
*
* REVISIT: The send will still block if we are unable to buffer the
* entire user-provided buffer which may be quite large. We will almost
* certainly need to have more than one free IOB, but we don't know how
* many more.
*/
if (udp_wrbuffer_test() < 0 || iob_navail(false) <= 0)
{
return -EWOULDBLOCK;
}
return OK;
}
/****************************************************************************
* Name: udp_sendbuffer_notify
*
* Description:
* Notify the send buffer semaphore
*
* Input Parameters:
* conn - The UDP connection of interest
*
* Assumptions:
* Called from user logic with the network locked.
*
****************************************************************************/
#if CONFIG_NET_SEND_BUFSIZE > 0
void udp_sendbuffer_notify(FAR struct udp_conn_s *conn)
{
int val = 0;
nxsem_get_value(&conn->sndsem, &val);
if (val < 0)
{
nxsem_post(&conn->sndsem);
}
}
#endif /* CONFIG_NET_SEND_BUFSIZE */
#endif /* CONFIG_NET && CONFIG_NET_UDP && CONFIG_NET_UDP_WRITE_BUFFERS */
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