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nuttx/net/sixlowpan/sixlowpan_tcpsend.c
Jiuzhu Dong 4d5a964f29 net: unify socket into file descriptor 
Change-Id: I9bcd21564e6c97d3edbb38aed1748c114160ea36
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
2021-03-03 19:01:41 -08:00

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/****************************************************************************
* net/sixlowpan/sixlowpan_tcpsend.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>
#include <inttypes.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/radiodev.h>
#include <nuttx/net/netstats.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "socket/socket.h"
#include "inet/inet.h"
#include "icmpv6/icmpv6.h"
#include "tcp/tcp.h"
#include "utils/utils.h"
#include "sixlowpan/sixlowpan_internal.h"
#if defined(CONFIG_NET_6LOWPAN) && defined(CONFIG_NET_TCP)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Buffer access helpers */
#define TCPBUF(dev) ((FAR struct tcp_hdr_s *)(&(dev)->d_buf[IPv6_HDRLEN]))
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* These are temporary stubs. Something like this would be needed to
* monitor the health of a IPv6 neighbor.
*/
#define neighbor_reachable(dev)
#define neighbor_notreachable(dev)
/****************************************************************************
* Private Types
****************************************************************************/
/* This is the state data provided to the send event handler. No actions
* can be taken until the until we receive the TX poll, then we can call
* sixlowpan_queue_frames() with this data strurcture.
*/
struct sixlowpan_send_s
{
FAR struct socket *s_sock; /* Internal socket reference */
FAR struct devif_callback_s *s_cb; /* Reference to callback
* instance */
sem_t s_waitsem; /* Supports waiting for
* driver events */
int s_result; /* The result of the transfer */
FAR const struct netdev_varaddr_s *s_destmac; /* Destination MAC address */
FAR const uint8_t *s_buf; /* Data to send */
size_t s_buflen; /* Length of data in buf */
ssize_t s_sent; /* The number of bytes sent */
uint32_t s_isn; /* Initial sequence number */
uint32_t s_acked; /* The number of bytes acked */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: sixlowpan_tcp_chksum
*
* Description:
* Perform the checksum calcaultion over the IPv6, protocol headers, and
* data payload as necessary.
*
* Input Parameters:
* ipv6tcp - A reference to a structure containing the IPv6 and TCP
* headers.
* buf - The beginning of the payload data
* buflen - The length of the payload data.
*
* Returned Value:
* The calculated checksum
*
****************************************************************************/
static uint16_t sixlowpan_tcp_chksum(FAR const struct ipv6tcp_hdr_s *ipv6tcp,
FAR const uint8_t *buf, uint16_t buflen)
{
uint16_t upperlen;
uint16_t tcplen;
uint16_t sum;
/* The length reported in the IPv6 header is the length of the payload
* that follows the header.
*/
upperlen = ((uint16_t)ipv6tcp->ipv6.len[0] << 8) + ipv6tcp->ipv6.len[1];
/* Verify some minimal assumptions */
if (upperlen > CONFIG_NET_6LOWPAN_PKTSIZE)
{
return 0;
}
/* The checksum is calculated starting with a pseudo-header of IPv6 header
* fields according to the IPv6 standard, which consists of the source
* and destination addresses, the packet length and the next header field.
*/
sum = upperlen + ipv6tcp->ipv6.proto;
/* Sum IP source and destination addresses. */
sum = chksum(sum, (FAR uint8_t *)ipv6tcp->ipv6.srcipaddr,
2 * sizeof(net_ipv6addr_t));
/* Sum the TCP header
*
* The TCP header length is encoded in the top 4 bits of the tcpoffset
* field (in units of 32-bit words).
*/
tcplen = ((uint16_t)ipv6tcp->tcp.tcpoffset >> 4) << 2;
sum = chksum(sum, (FAR uint8_t *)&ipv6tcp->tcp, tcplen);
/* Sum payload data. */
sum = chksum(sum, buf, buflen);
return (sum == 0) ? 0xffff : htons(sum);
}
/****************************************************************************
* Name: sixlowpan_tcp_header
*
* Description:
* sixlowpan_tcp_header() will construct the IPv6 and TCP headers
*
* Input Parameters:
* conn - An instance of the TCP connection structure.
* dev - The network device that will route the packet
* buf - Data to send
* bulen - Length of data to send
* ipv6tcp - The location to save the IPv6 + TCP header
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned on
* failure.
*
* Assumptions:
* Called with the network locked.
*
****************************************************************************/
static int sixlowpan_tcp_header(FAR struct tcp_conn_s *conn,
FAR struct net_driver_s *dev,
FAR const void *buf, size_t buflen,
FAR struct ipv6tcp_hdr_s *ipv6tcp)
{
uint16_t iplen;
/* Initialize the IPv6/TCP headers */
ipv6tcp->ipv6.vtc = 0x60;
ipv6tcp->ipv6.tcf = 0x00;
ipv6tcp->ipv6.flow = 0x00;
ipv6tcp->ipv6.proto = IP_PROTO_TCP;
ipv6tcp->ipv6.ttl = IP_TTL;
/* The IPv6 header length field does not include the size of IPv6 IP
* header.
*/
iplen = buflen + TCP_HDRLEN;
ipv6tcp->ipv6.len[0] = (iplen >> 8);
ipv6tcp->ipv6.len[1] = (iplen & 0xff);
/* Copy the source and destination addresses */
net_ipv6addr_hdrcopy(ipv6tcp->ipv6.destipaddr, conn->u.ipv6.raddr);
if (!net_ipv6addr_cmp(conn->u.ipv6.laddr, g_ipv6_unspecaddr))
{
net_ipv6addr_hdrcopy(ipv6tcp->ipv6.srcipaddr, conn->u.ipv6.laddr);
}
else
{
net_ipv6addr_hdrcopy(ipv6tcp->ipv6.srcipaddr, dev->d_ipv6addr);
}
ninfo("IPv6 length: %d\n",
((int)ipv6tcp->ipv6.len[0] << 8) + ipv6tcp->ipv6.len[1]);
#ifdef CONFIG_NET_STATISTICS
g_netstats.ipv6.sent++;
#endif
/* Initialize the TCP header */
ipv6tcp->tcp.srcport = conn->lport; /* Local port */
ipv6tcp->tcp.destport = conn->rport; /* Connected remote port */
ipv6tcp->tcp.tcpoffset = (TCP_HDRLEN / 4) << 4; /* No optdata */
ipv6tcp->tcp.flags = TCP_ACK | TCP_PSH; /* No urgent data */
ipv6tcp->tcp.urgp[0] = 0; /* No urgent data */
ipv6tcp->tcp.urgp[1] = 0;
/* Set the sequency number information.
*
* REVISIT: There is currently no wait for the data to be ACKed and,
* hence, no mechanism to retransmit the packet.
*/
memcpy(ipv6tcp->tcp.ackno, conn->rcvseq, 4); /* ACK number */
memcpy(ipv6tcp->tcp.seqno, conn->sndseq, 4); /* Sequence number */
/* Set the TCP window */
if (conn->tcpstateflags & TCP_STOPPED)
{
/* If the connection has issued TCP_STOPPED, we advertise a zero
* window so that the remote host will stop sending data.
*/
ipv6tcp->tcp.wnd[0] = 0;
ipv6tcp->tcp.wnd[1] = 0;
}
else
{
/* Update the TCP received window based on I/O buffer availability */
uint16_t recvwndo = tcp_get_recvwindow(dev, conn);
/* Set the TCP Window */
ipv6tcp->tcp.wnd[0] = recvwndo >> 8;
ipv6tcp->tcp.wnd[1] = recvwndo & 0xff;
/* Update the Receiver Window */
conn->rcv_wnd = recvwndo;
}
/* Calculate TCP checksum. */
ipv6tcp->tcp.tcpchksum = 0;
ipv6tcp->tcp.tcpchksum = ~sixlowpan_tcp_chksum(ipv6tcp, buf, buflen);
ninfo("Outgoing TCP packet length: %d bytes\n", iplen + IPv6_HDRLEN);
return OK;
}
/****************************************************************************
* Name: tcp_send_eventhandler
*
* Description:
* This function is called with the network locked to perform the actual
* TCP send operation when polled by the lower, device interfacing layer.
*
* Input Parameters:
* dev - The structure of the network driver that generated the event.
* pvconn - The connection structure associated with the socket
* pvpriv - The event handler's private data argument
* flags - Set of events describing why the callback was invoked
*
* Returned Value:
* None
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static uint16_t tcp_send_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvconn,
FAR void *pvpriv, uint16_t flags)
{
FAR struct sixlowpan_send_s *sinfo = (FAR struct sixlowpan_send_s *)pvpriv;
FAR struct tcp_conn_s *conn = (FAR struct tcp_conn_s *)pvconn;
struct ipv6tcp_hdr_s ipv6tcp;
int ret;
/* Verify that this is an IEEE802.15.4 network driver. */
if (dev->d_lltype != NET_LL_IEEE802154 &&
dev->d_lltype != NET_LL_PKTRADIO)
{
ninfo("Not a compatible network device\n");
return flags;
}
/* Check if the IEEE802.15.4 network driver went down */
if ((flags & NETDEV_DOWN) != 0)
{
nwarn("WARNING: Device is down\n");
sinfo->s_result = -ENOTCONN;
goto end_wait;
}
/* The TCP socket is connected and, hence, should be bound to a device.
* Make sure that the polling device is the one that we are bound to.
*/
DEBUGASSERT(conn->dev != NULL);
if (dev != conn->dev)
{
ninfo("Not the connected device\n");
return flags;
}
ninfo("flags: %04x acked: %" PRIu32 " sent: %zu\n",
flags, sinfo->s_acked, sinfo->s_sent);
/* If this packet contains an acknowledgement, then update the count of
* acknowledged bytes.
*/
if ((flags & TCP_ACKDATA) != 0)
{
FAR struct tcp_hdr_s *tcp = TCPBUF(dev);
/* The current acknowledgement number number is the (relative) offset
* of the of the next byte needed by the receiver. The s_isn is the
* offset of the first byte to send to the receiver. The difference
* is the number of bytes to be acknowledged.
*/
sinfo->s_acked = tcp_getsequence(tcp->ackno) - sinfo->s_isn;
ninfo("ACK: acked=%" PRId32 " sent=%zd buflen=%zd\n",
sinfo->s_acked, sinfo->s_sent, sinfo->s_buflen);
/* Have all of the bytes in the buffer been sent and acknowledged? */
if (sinfo->s_acked >= sinfo->s_buflen)
{
/* Yes. Then sinfo->s_buflen should hold the number of bytes
* actually sent.
*/
sinfo->s_result = sinfo->s_sent;
goto end_wait;
}
/* No.. fall through to send more data if necessary */
}
/* Check if we are being asked to retransmit data */
else if ((flags & TCP_REXMIT) != 0)
{
/* Yes.. in this case, reset the number of bytes that have been sent
* to the number of bytes that have been ACKed.
*/
sinfo->s_sent = sinfo->s_acked;
/* Fall through to re-send data from the last that was ACKed */
}
/* Check for a loss of connection */
else if ((flags & TCP_DISCONN_EVENTS) != 0)
{
FAR struct socket *psock = sinfo->s_sock;
nwarn("WARNING: Lost connection\n");
/* We could get here recursively through the callback actions of
* tcp_lost_connection(). So don't repeat that action if we have
* already been disconnected.
*/
DEBUGASSERT(psock != NULL);
if (_SS_ISCONNECTED(psock->s_flags))
{
/* Report the disconnection event to all socket clones */
tcp_lost_connection(psock, sinfo->s_cb, flags);
}
/* Report not connected to the sender */
sinfo->s_result = -ENOTCONN;
goto end_wait;
}
/* Check if the outgoing packet is available (it may have been claimed
* by a sendto event handler serving a different thread).
*/
#if 0 /* We can't really support multiple senders on the same TCP socket */
else if (dev->d_sndlen > 0)
{
/* Another thread has beat us sending data, wait for the next poll */
return flags;
}
#endif
/* We get here if (1) not all of the data has been ACKed, (2) we have been
* asked to retransmit data, (3) the connection is still healthy, and (4)
* the outgoing packet is available for our use. In this case, we are
* now free to send more data to receiver -- UNLESS the buffer contains
* unprocessed incoming data. In that event, we will have to wait for the
* next polling cycle.
*/
if ((flags & WPAN_NEWDATA) == 0 && sinfo->s_sent < sinfo->s_buflen)
{
uint32_t seqno;
uint16_t winleft;
uint16_t sndlen;
/* Get the amount of TCP payload data that we can send in the next
* packet.
*/
sndlen = sinfo->s_buflen - sinfo->s_sent;
if (sndlen > conn->mss)
{
sndlen = conn->mss;
}
winleft = conn->snd_wnd - sinfo->s_sent + sinfo->s_acked;
if (sndlen > winleft)
{
sndlen = winleft;
}
ninfo("s_buflen=%zu s_sent=%zu mss=%u snd_wnd=%u sndlen=%d\n",
sinfo->s_buflen, sinfo->s_sent, conn->mss, conn->snd_wnd,
sndlen);
if (sndlen > 0)
{
/* Set the sequence number for this packet. NOTE: The network
* updates sndseq on receipt of ACK *before* this function is
* called. In that case sndseq will point to the next
* unacknowledged byte (which might have already been sent). We
* will overwrite the value of sndseq here before the packet is
* sent.
*/
seqno = sinfo->s_sent + sinfo->s_isn;
ninfo("Sending: sndseq %08" PRIx32 "->%08" PRIx32 "\n",
tcp_getsequence(conn->sndseq), seqno);
tcp_setsequence(conn->sndseq, seqno);
/* Create the IPv6 + TCP header */
ret = sixlowpan_tcp_header(conn, dev, &sinfo->s_buf[sinfo->s_sent],
sndlen, &ipv6tcp);
if (ret < 0)
{
nerr("ERROR: sixlowpan_tcp_header failed: %d\n", ret);
sinfo->s_result = ret;
goto end_wait;
}
/* Transfer the frame list to the IEEE802.15.4 MAC device */
ret = sixlowpan_queue_frames((FAR struct radio_driver_s *)dev,
&ipv6tcp.ipv6,
&sinfo->s_buf[sinfo->s_sent], sndlen,
sinfo->s_destmac);
if (ret < 0)
{
nerr("ERROR: sixlowpan_queue_frames failed: %d\n", ret);
sinfo->s_result = ret;
goto end_wait;
}
/* Increment the count of bytes sent, the number of unacked bytes,
* and the total count of TCP packets sent.
*
* NOTE: tcp_appsend() normally increments conn->tx_unacked based
* on the value of dev->d_sndlen. However, dev->d_len is always
* zero for 6LoWPAN since it does not send via the dev->d_buf
* but, rather, uses a backdoor frame interface with the IEEE
* 802.15.4 MAC.
*/
sinfo->s_sent += sndlen;
conn->tx_unacked += sndlen;
#ifdef CONFIG_NET_TCP_WRITE_BUFFERS
/* For compatibility with buffered send logic */
conn->sndseq_max = tcp_addsequence(conn->sndseq, conn->tx_unacked);
#endif
#ifdef CONFIG_NET_STATISTICS
g_netstats.tcp.sent++;
#endif
ninfo("Sent: acked=%" PRId32 " sent=%zd "
"buflen=%zd tx_unacked=%" PRId32 "\n",
sinfo->s_acked, sinfo->s_sent, sinfo->s_buflen,
(uint32_t)conn->tx_unacked);
}
}
/* Continue waiting */
return flags;
end_wait:
/* Do not allow any further callbacks */
sinfo->s_cb->flags = 0;
sinfo->s_cb->priv = NULL;
sinfo->s_cb->event = NULL;
/* There are no outstanding, unacknowledged bytes */
conn->tx_unacked = 0;
/* Wake up the waiting thread */
nxsem_post(&sinfo->s_waitsem);
return flags;
}
/****************************************************************************
* Name: sixlowpan_send_packet
*
* Description:
* Process an outgoing TCP packet. Takes an IP packet and formats it to
* be sent on an 802.15.4 network using 6lowpan. Called from common TCP
* send logic.
*
* The payload data is in the caller 'buf' and is of length 'buflen'.
* Compressed headers will be added and if necessary the packet is
* fragmented. The resulting packet/fragments are submitted to the MAC
* via the network driver r_req_data method.
*
* Input Parameters:
* psock - An instance of the internal socket structure.
* dev - The IEEE802.15.4 MAC network driver interface.
* conn - TCP connection structure
* buf - Data to send
* len - Length of data to send
* destmac - The IEEE802.15.4 MAC address of the destination
* timeout - Send timeout in milliseconds
*
* Returned Value:
* Ok is returned on success; Otherwise a negated errno value is returned.
* This function is expected to fail if the driver is not an IEEE802.15.4
* MAC network driver. In that case, the logic will fall back to normal
* IPv4/IPv6 formatting.
*
* Assumptions:
* Called with the network locked.
*
****************************************************************************/
static int sixlowpan_send_packet(FAR struct socket *psock,
FAR struct net_driver_s *dev,
FAR struct tcp_conn_s *conn,
FAR const uint8_t *buf, size_t len,
FAR const struct netdev_varaddr_s *destmac,
unsigned int timeout)
{
struct sixlowpan_send_s sinfo;
ninfo("len=%lu timeout=%u\n", (unsigned long)len, timeout);
DEBUGASSERT(psock != NULL && dev != NULL && conn != NULL && buf != NULL &&
destmac != NULL);
memset(&sinfo, 0, sizeof(struct sixlowpan_send_s));
net_lock();
if (len > 0)
{
/* Allocate resources to receive a callback.
*
* The second parameter is NULL meaning that we can get only
* device related events, no connect-related events.
*/
sinfo.s_cb = tcp_callback_alloc(conn);
if (sinfo.s_cb != NULL)
{
int ret;
/* Initialize the send state structure */
nxsem_init(&sinfo.s_waitsem, 0, 0);
nxsem_set_protocol(&sinfo.s_waitsem, SEM_PRIO_NONE);
sinfo.s_sock = psock;
sinfo.s_result = -EBUSY;
sinfo.s_destmac = destmac;
sinfo.s_buf = buf;
sinfo.s_buflen = len;
/* Set up the initial sequence number */
sinfo.s_isn = tcp_getsequence(conn->sndseq);
/* Set up the callback in the connection */
sinfo.s_cb->flags = (NETDEV_DOWN | TCP_ACKDATA | TCP_REXMIT |
TCP_DISCONN_EVENTS | WPAN_POLL);
sinfo.s_cb->priv = (FAR void *)&sinfo;
sinfo.s_cb->event = tcp_send_eventhandler;
/* There is no outstanding, unacknowledged data after this
* initial sequence number.
*/
conn->tx_unacked = 0;
/* Notify the IEEE802.15.4 MAC that we have data to send. */
netdev_txnotify_dev(dev);
/* Wait for the send to complete or an error to occur.
* net_timedwait will also terminate if a signal is received.
*/
ninfo("Wait for send complete\n");
for (; ; )
{
uint32_t acked = sinfo.s_acked;
ret = net_timedwait(&sinfo.s_waitsem, timeout);
if (ret != -ETIMEDOUT || acked == sinfo.s_acked)
{
break; /* Timeout without any progress */
}
}
if (ret < 0)
{
sinfo.s_result = ret;
}
/* Make sure that no further events are processed */
tcp_callback_free(conn, sinfo.s_cb);
}
}
nxsem_destroy(&sinfo.s_waitsem);
net_unlock();
return (sinfo.s_result < 0 ? sinfo.s_result : len);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: psock_6lowpan_tcp_send
*
* Description:
* psock_6lowpan_tcp_send() call may be used only when the TCP socket is
* in a connected state (so that the intended recipient is known).
*
* Input Parameters:
* psock - An instance of the internal socket structure.
* buf - Data to send
* bulen - Length of data to send
*
* Returned Value:
* On success, returns the number of characters sent. On error,
* -1 is returned, and errno is set appropriately. Returned error numbers
* must be consistent with definition of errors reported by send() or
* sendto().
*
* Assumptions:
* Called with the network locked.
*
****************************************************************************/
ssize_t psock_6lowpan_tcp_send(FAR struct socket *psock, FAR const void *buf,
size_t buflen)
{
FAR struct tcp_conn_s *conn;
FAR struct net_driver_s *dev;
struct netdev_varaddr_s destmac;
int ret;
ninfo("buflen %lu\n", (unsigned long)buflen);
sixlowpan_dumpbuffer("Outgoing TCP payload", buf, buflen);
DEBUGASSERT(psock != NULL && psock->s_conn != NULL);
DEBUGASSERT(psock->s_type == SOCK_STREAM);
/* Make sure that this is a valid socket */
if (psock == NULL || psock->s_conn == NULL)
{
nerr("ERROR: Invalid socket\n");
return (ssize_t)-EBADF;
}
/* Make sure that this is a connected TCP socket */
if (psock->s_type != SOCK_STREAM || !_SS_ISCONNECTED(psock->s_flags))
{
nerr("ERROR: Not connected\n");
return (ssize_t)-ENOTCONN;
}
/* Get the underlying TCP connection structure */
conn = (FAR struct tcp_conn_s *)psock->s_conn;
#ifdef CONFIG_NET_IPv4
/* Ignore if not IPv6 domain */
if (conn->domain != PF_INET6)
{
nwarn("WARNING: Not IPv6\n");
return (ssize_t)-EPROTOTYPE;
}
#endif
/* Route outgoing message to the correct device */
dev = netdev_findby_ripv6addr(conn->u.ipv6.laddr, conn->u.ipv6.raddr);
if (dev == NULL)
{
nwarn("WARNING: Not routable\n");
return (ssize_t)-ENETUNREACH;
}
/* Some network devices support different link layer protocols.
* Check if this device has the hooks to support 6LoWPAN.
*/
if (dev->d_lltype != NET_LL_IEEE802154 &&
dev->d_lltype != NET_LL_PKTRADIO)
{
nwarn("WARNING: Not a compatible network device\n");
return (ssize_t)-ENONET;
}
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
/* Make sure that the IP address mapping is in the Neighbor Table */
ret = icmpv6_neighbor(conn->u.ipv6.raddr);
if (ret < 0)
{
nerr("ERROR: Not reachable\n");
return (ssize_t)-ENETUNREACH;
}
#endif
/* Get the IEEE 802.15.4 MAC address of the next hop. */
ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)dev,
conn->u.ipv6.raddr, &destmac);
if (ret < 0)
{
nerr("ERROR: Failed to get dest MAC address: %d\n", ret);
return (ssize_t)ret;
}
/* Send the TCP packets, breaking down the potential large user buffer
* into smaller packets that can be reassembled in the allocated MTU
* packet buffer.
*/
ret = sixlowpan_send_packet(psock, dev, conn, buf, buflen, &destmac,
_SO_TIMEOUT(psock->s_sndtimeo));
if (ret < 0)
{
nerr("ERROR: sixlowpan_send_packet() failed: %d\n", ret);
return (ssize_t)ret;
}
return (ssize_t)buflen;
}
/****************************************************************************
* Name: sixlowpan_tcp_send
*
* Description:
* TCP output comes through three different mechansims. Either from:
*
* 1. TCP socket output. For the case of TCP output to an
* IEEE802.15.4, the TCP output is caught in the socket
* send()/sendto() logic and and redirected to psock_6lowpan_tcp_send().
* 2. TCP output from the TCP state machine. That will occur
* during TCP packet processing by the TCP state meachine.
* 3. TCP output resulting from TX or timer polling
*
* Cases 2 and 3 will be handled here. Logic in ipv6_tcp_input(),
* devif_poll(), and devif_timer() detect if (1) an attempt to return with
* d_len > 0 and (2) that the device is an IEEE802.15.4 MAC network
* driver. Under those conditions, this function will be called to create
* the IEEE80215.4 frames.
*
* Input Parameters:
* dev - The network device containing the packet to be sent.
* fwddev - The network device used to send the data. This will be the
* same device except for the IP forwarding case where packets
* are sent across devices.
* ipv6 - A pointer to the IPv6 header in dev->d_buf which lies AFTER
* the L1 header. NOTE: dev->d_len must have been decremented
* by the size of any preceding MAC header.
*
* Returned Value:
* None
*
* Assumptions:
* Called with the network locked.
*
****************************************************************************/
void sixlowpan_tcp_send(FAR struct net_driver_s *dev,
FAR struct net_driver_s *fwddev,
FAR struct ipv6_hdr_s *ipv6)
{
DEBUGASSERT(dev != NULL && dev->d_len > 0 && fwddev != NULL);
/* Double check */
ninfo("d_len %u\n", dev->d_len);
sixlowpan_dumpbuffer("Outgoing TCP packet",
(FAR const uint8_t *)ipv6, dev->d_len);
if (dev != NULL && dev->d_len > 0 && fwddev != NULL)
{
FAR struct ipv6tcp_hdr_s *ipv6hdr;
/* The IPv6 header followed by a TCP headers should lie at the
* beginning of d_buf since there is no link layer protocol header
* and the TCP state machine should only response with TCP packets.
*/
ipv6hdr = (FAR struct ipv6tcp_hdr_s *)ipv6;
/* The TCP data payload should follow the IPv6 header plus the
* protocol header.
*/
if (ipv6hdr->ipv6.proto != IP_PROTO_TCP)
{
nwarn("WARNING: Expected TCP prototype: %u vs %u\n",
ipv6hdr->ipv6.proto, IP_PROTO_TCP);
}
else
{
struct netdev_varaddr_s destmac;
FAR uint8_t *buf;
uint16_t hdrlen;
uint16_t buflen;
int ret;
/* Get the IEEE 802.15.4 MAC address of the next hop. */
ret = sixlowpan_nexthopaddr((FAR struct radio_driver_s *)fwddev,
ipv6hdr->ipv6.destipaddr, &destmac);
if (ret < 0)
{
nerr("ERROR: Failed to get dest MAC address: %d\n", ret);
goto drop;
}
/* Get the IPv6 + TCP combined header length. The size of the TCP
* header is encoded in the top 4 bits of the tcpoffset field (in
* units of 32-bit words).
*/
hdrlen = IPv6_HDRLEN +
(((uint16_t)ipv6hdr->tcp.tcpoffset >> 4) << 2);
/* Drop the packet if the buffer length is less than this. */
if (hdrlen > dev->d_len)
{
nwarn("WARNING: Dropping small TCP packet: %u < %u\n",
buflen, hdrlen);
}
else
{
/* Convert the outgoing packet into a frame list. */
buf = (FAR uint8_t *)ipv6 + hdrlen;
buflen = dev->d_len - hdrlen;
sixlowpan_queue_frames(
(FAR struct radio_driver_s *)fwddev,
&ipv6hdr->ipv6, buf, buflen, &destmac);
}
}
}
drop:
dev->d_len = 0;
}
#endif /* CONFIG_NET_6LOWPAN && CONFIG_NET_TCP */
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