mirror of
https://github.com/lwip-tcpip/lwip.git
synced 2024-12-25 18:14:53 +00:00
2191 lines
75 KiB
C
2191 lines
75 KiB
C
/**
|
|
* @file
|
|
* Transmission Control Protocol, outgoing traffic
|
|
*
|
|
* The output functions of TCP.
|
|
*
|
|
* There are two distinct ways for TCP segments to get sent:
|
|
* - queued data: these are segments transferring data or segments containing
|
|
* SYN or FIN (which both count as one sequence number). They are created as
|
|
* struct @ref pbuf together with a struct tcp_seg and enqueue to the
|
|
* unsent list of the pcb. They are sent by tcp_output:
|
|
* - @ref tcp_write : creates data segments
|
|
* - @ref tcp_split_unsent_seg : splits a data segment
|
|
* - @ref tcp_enqueue_flags : creates SYN-only or FIN-only segments
|
|
* - @ref tcp_output / tcp_output_segment : finalize the tcp header
|
|
* (e.g. sequence numbers, options, checksum) and output to IP
|
|
* - the various tcp_rexmit functions shuffle around segments between the
|
|
* unsent an unacked lists to retransmit them
|
|
* - tcp_create_segment and tcp_pbuf_prealloc allocate pbuf and
|
|
* segment for these functions
|
|
* - direct send: these segments don't contain data but control the connection
|
|
* behaviour. They are created as pbuf only and sent directly without
|
|
* enqueueing them:
|
|
* - @ref tcp_send_empty_ack sends an ACK-only segment
|
|
* - @ref tcp_rst sends a RST segment
|
|
* - @ref tcp_keepalive sends a keepalive segment
|
|
* - @ref tcp_zero_window_probe sends a window probe segment
|
|
* - tcp_output_alloc_header allocates a header-only pbuf for these functions
|
|
*/
|
|
|
|
/*
|
|
* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without modification,
|
|
* are permitted provided that the following conditions are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
* this list of conditions and the following disclaimer in the documentation
|
|
* and/or other materials provided with the distribution.
|
|
* 3. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
|
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
|
|
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
|
|
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
|
|
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
|
|
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
|
|
* OF SUCH DAMAGE.
|
|
*
|
|
* This file is part of the lwIP TCP/IP stack.
|
|
*
|
|
* Author: Adam Dunkels <adam@sics.se>
|
|
*
|
|
*/
|
|
|
|
#include "lwip/opt.h"
|
|
|
|
#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
|
|
|
|
#include "lwip/priv/tcp_priv.h"
|
|
#include "lwip/def.h"
|
|
#include "lwip/mem.h"
|
|
#include "lwip/memp.h"
|
|
#include "lwip/ip_addr.h"
|
|
#include "lwip/netif.h"
|
|
#include "lwip/inet_chksum.h"
|
|
#include "lwip/stats.h"
|
|
#include "lwip/ip6.h"
|
|
#include "lwip/ip6_addr.h"
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
#include "lwip/sys.h"
|
|
#endif
|
|
|
|
#include <string.h>
|
|
|
|
#ifdef LWIP_HOOK_FILENAME
|
|
#include LWIP_HOOK_FILENAME
|
|
#endif
|
|
|
|
/* Allow to add custom TCP header options by defining this hook */
|
|
#ifdef LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH
|
|
#define LWIP_TCP_OPT_LENGTH_SEGMENT(flags, pcb) LWIP_HOOK_TCP_OUT_TCPOPT_LENGTH(pcb, LWIP_TCP_OPT_LENGTH(flags))
|
|
#else
|
|
#define LWIP_TCP_OPT_LENGTH_SEGMENT(flags, pcb) LWIP_TCP_OPT_LENGTH(flags)
|
|
#endif
|
|
|
|
/* Define some copy-macros for checksum-on-copy so that the code looks
|
|
nicer by preventing too many ifdef's. */
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
#define TCP_DATA_COPY(dst, src, len, seg) do { \
|
|
tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), \
|
|
len, &seg->chksum, &seg->chksum_swapped); \
|
|
seg->flags |= TF_SEG_DATA_CHECKSUMMED; } while(0)
|
|
#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) \
|
|
tcp_seg_add_chksum(LWIP_CHKSUM_COPY(dst, src, len), len, chksum, chksum_swapped);
|
|
#else /* TCP_CHECKSUM_ON_COPY*/
|
|
#define TCP_DATA_COPY(dst, src, len, seg) MEMCPY(dst, src, len)
|
|
#define TCP_DATA_COPY2(dst, src, len, chksum, chksum_swapped) MEMCPY(dst, src, len)
|
|
#endif /* TCP_CHECKSUM_ON_COPY*/
|
|
|
|
/** Define this to 1 for an extra check that the output checksum is valid
|
|
* (usefule when the checksum is generated by the application, not the stack) */
|
|
#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
|
#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK 0
|
|
#endif
|
|
/* Allow to override the failure of sanity check from warning to e.g. hard failure */
|
|
#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
|
#ifndef TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL
|
|
#define TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL(msg) LWIP_DEBUGF(TCP_DEBUG | LWIP_DBG_LEVEL_WARNING, msg)
|
|
#endif
|
|
#endif
|
|
|
|
#if TCP_OVERSIZE
|
|
/** The size of segment pbufs created when TCP_OVERSIZE is enabled */
|
|
#ifndef TCP_OVERSIZE_CALC_LENGTH
|
|
#define TCP_OVERSIZE_CALC_LENGTH(length) ((length) + TCP_OVERSIZE)
|
|
#endif
|
|
#endif
|
|
|
|
/* Forward declarations.*/
|
|
static err_t tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb, struct netif *netif);
|
|
|
|
/* tcp_route: common code that returns a fixed bound netif or calls ip_route */
|
|
static struct netif *
|
|
tcp_route(const struct tcp_pcb *pcb, const ip_addr_t *src, const ip_addr_t *dst)
|
|
{
|
|
LWIP_UNUSED_ARG(src); /* in case IPv4-only and source-based routing is disabled */
|
|
|
|
if ((pcb != NULL) && (pcb->netif_idx != NETIF_NO_INDEX)) {
|
|
return netif_get_by_index(pcb->netif_idx);
|
|
} else {
|
|
return ip_route(src, dst);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Create a TCP segment with prefilled header.
|
|
*
|
|
* Called by @ref tcp_write, @ref tcp_enqueue_flags and @ref tcp_split_unsent_seg
|
|
*
|
|
* @param pcb Protocol control block for the TCP connection.
|
|
* @param p pbuf that is used to hold the TCP header.
|
|
* @param hdrflags TCP flags for header.
|
|
* @param seqno TCP sequence number of this packet
|
|
* @param optflags options to include in TCP header
|
|
* @return a new tcp_seg pointing to p, or NULL.
|
|
* The TCP header is filled in except ackno and wnd.
|
|
* p is freed on failure.
|
|
*/
|
|
static struct tcp_seg *
|
|
tcp_create_segment(const struct tcp_pcb *pcb, struct pbuf *p, u8_t hdrflags, u32_t seqno, u8_t optflags)
|
|
{
|
|
struct tcp_seg *seg;
|
|
u8_t optlen;
|
|
|
|
LWIP_ASSERT("tcp_create_segment: invalid pcb", pcb != NULL);
|
|
LWIP_ASSERT("tcp_create_segment: invalid pbuf", p != NULL);
|
|
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
|
|
|
|
if ((seg = (struct tcp_seg *)memp_malloc(MEMP_TCP_SEG)) == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_create_segment: no memory.\n"));
|
|
pbuf_free(p);
|
|
return NULL;
|
|
}
|
|
seg->flags = optflags;
|
|
seg->next = NULL;
|
|
seg->p = p;
|
|
LWIP_ASSERT("p->tot_len >= optlen", p->tot_len >= optlen);
|
|
seg->len = p->tot_len - optlen;
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
seg->oversize_left = 0;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
seg->chksum = 0;
|
|
seg->chksum_swapped = 0;
|
|
/* check optflags */
|
|
LWIP_ASSERT("invalid optflags passed: TF_SEG_DATA_CHECKSUMMED",
|
|
(optflags & TF_SEG_DATA_CHECKSUMMED) == 0);
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/* build TCP header */
|
|
if (pbuf_add_header(p, TCP_HLEN)) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_create_segment: no room for TCP header in pbuf.\n"));
|
|
TCP_STATS_INC(tcp.err);
|
|
tcp_seg_free(seg);
|
|
return NULL;
|
|
}
|
|
seg->tcphdr = (struct tcp_hdr *)seg->p->payload;
|
|
seg->tcphdr->src = lwip_htons(pcb->local_port);
|
|
seg->tcphdr->dest = lwip_htons(pcb->remote_port);
|
|
seg->tcphdr->seqno = lwip_htonl(seqno);
|
|
/* ackno is set in tcp_output */
|
|
TCPH_HDRLEN_FLAGS_SET(seg->tcphdr, (5 + optlen / 4), hdrflags);
|
|
/* wnd and chksum are set in tcp_output */
|
|
seg->tcphdr->urgp = 0;
|
|
return seg;
|
|
}
|
|
|
|
/**
|
|
* Allocate a PBUF_RAM pbuf, perhaps with extra space at the end.
|
|
*
|
|
* This function is like pbuf_alloc(layer, length, PBUF_RAM) except
|
|
* there may be extra bytes available at the end.
|
|
*
|
|
* Called by @ref tcp_write
|
|
*
|
|
* @param layer flag to define header size.
|
|
* @param length size of the pbuf's payload.
|
|
* @param max_length maximum usable size of payload+oversize.
|
|
* @param oversize pointer to a u16_t that will receive the number of usable tail bytes.
|
|
* @param pcb The TCP connection that will enqueue the pbuf.
|
|
* @param apiflags API flags given to tcp_write.
|
|
* @param first_seg true when this pbuf will be used in the first enqueued segment.
|
|
*/
|
|
#if TCP_OVERSIZE
|
|
static struct pbuf *
|
|
tcp_pbuf_prealloc(pbuf_layer layer, u16_t length, u16_t max_length,
|
|
u16_t *oversize, const struct tcp_pcb *pcb, u8_t apiflags,
|
|
u8_t first_seg)
|
|
{
|
|
struct pbuf *p;
|
|
u16_t alloc = length;
|
|
|
|
LWIP_ASSERT("tcp_pbuf_prealloc: invalid oversize", oversize != NULL);
|
|
LWIP_ASSERT("tcp_pbuf_prealloc: invalid pcb", pcb != NULL);
|
|
|
|
#if LWIP_NETIF_TX_SINGLE_PBUF
|
|
LWIP_UNUSED_ARG(max_length);
|
|
LWIP_UNUSED_ARG(pcb);
|
|
LWIP_UNUSED_ARG(apiflags);
|
|
LWIP_UNUSED_ARG(first_seg);
|
|
alloc = max_length;
|
|
#else /* LWIP_NETIF_TX_SINGLE_PBUF */
|
|
if (length < max_length) {
|
|
/* Should we allocate an oversized pbuf, or just the minimum
|
|
* length required? If tcp_write is going to be called again
|
|
* before this segment is transmitted, we want the oversized
|
|
* buffer. If the segment will be transmitted immediately, we can
|
|
* save memory by allocating only length. We use a simple
|
|
* heuristic based on the following information:
|
|
*
|
|
* Did the user set TCP_WRITE_FLAG_MORE?
|
|
*
|
|
* Will the Nagle algorithm defer transmission of this segment?
|
|
*/
|
|
if ((apiflags & TCP_WRITE_FLAG_MORE) ||
|
|
(!(pcb->flags & TF_NODELAY) &&
|
|
(!first_seg ||
|
|
pcb->unsent != NULL ||
|
|
pcb->unacked != NULL))) {
|
|
alloc = LWIP_MIN(max_length, LWIP_MEM_ALIGN_SIZE(TCP_OVERSIZE_CALC_LENGTH(length)));
|
|
}
|
|
}
|
|
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
|
|
p = pbuf_alloc(layer, alloc, PBUF_RAM);
|
|
if (p == NULL) {
|
|
return NULL;
|
|
}
|
|
LWIP_ASSERT("need unchained pbuf", p->next == NULL);
|
|
*oversize = p->len - length;
|
|
/* trim p->len to the currently used size */
|
|
p->len = p->tot_len = length;
|
|
return p;
|
|
}
|
|
#else /* TCP_OVERSIZE */
|
|
#define tcp_pbuf_prealloc(layer, length, mx, os, pcb, api, fst) pbuf_alloc((layer), (length), PBUF_RAM)
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/** Add a checksum of newly added data to the segment.
|
|
*
|
|
* Called by tcp_write and tcp_split_unsent_seg.
|
|
*/
|
|
static void
|
|
tcp_seg_add_chksum(u16_t chksum, u16_t len, u16_t *seg_chksum,
|
|
u8_t *seg_chksum_swapped)
|
|
{
|
|
u32_t helper;
|
|
/* add chksum to old chksum and fold to u16_t */
|
|
helper = chksum + *seg_chksum;
|
|
chksum = FOLD_U32T(helper);
|
|
if ((len & 1) != 0) {
|
|
*seg_chksum_swapped = 1 - *seg_chksum_swapped;
|
|
chksum = SWAP_BYTES_IN_WORD(chksum);
|
|
}
|
|
*seg_chksum = chksum;
|
|
}
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/** Checks if tcp_write is allowed or not (checks state, snd_buf and snd_queuelen).
|
|
*
|
|
* @param pcb the tcp pcb to check for
|
|
* @param len length of data to send (checked agains snd_buf)
|
|
* @return ERR_OK if tcp_write is allowed to proceed, another err_t otherwise
|
|
*/
|
|
static err_t
|
|
tcp_write_checks(struct tcp_pcb *pcb, u16_t len)
|
|
{
|
|
LWIP_ASSERT("tcp_write_checks: invalid pcb", pcb != NULL);
|
|
|
|
/* connection is in invalid state for data transmission? */
|
|
if ((pcb->state != ESTABLISHED) &&
|
|
(pcb->state != CLOSE_WAIT) &&
|
|
(pcb->state != SYN_SENT) &&
|
|
(pcb->state != SYN_RCVD)) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_STATE | LWIP_DBG_LEVEL_SEVERE, ("tcp_write() called in invalid state\n"));
|
|
return ERR_CONN;
|
|
} else if (len == 0) {
|
|
return ERR_OK;
|
|
}
|
|
|
|
/* fail on too much data */
|
|
if (len > pcb->snd_buf) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("tcp_write: too much data (len=%"U16_F" > snd_buf=%"TCPWNDSIZE_F")\n",
|
|
len, pcb->snd_buf));
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
return ERR_MEM;
|
|
}
|
|
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: queuelen: %"TCPWNDSIZE_F"\n", (tcpwnd_size_t)pcb->snd_queuelen));
|
|
|
|
/* If total number of pbufs on the unsent/unacked queues exceeds the
|
|
* configured maximum, return an error */
|
|
/* check for configured max queuelen and possible overflow */
|
|
if (pcb->snd_queuelen >= LWIP_MIN(TCP_SND_QUEUELEN, (TCP_SNDQUEUELEN_OVERFLOW + 1))) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SEVERE, ("tcp_write: too long queue %"U16_F" (max %"U16_F")\n",
|
|
pcb->snd_queuelen, (u16_t)TCP_SND_QUEUELEN));
|
|
TCP_STATS_INC(tcp.memerr);
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
return ERR_MEM;
|
|
}
|
|
if (pcb->snd_queuelen != 0) {
|
|
LWIP_ASSERT("tcp_write: pbufs on queue => at least one queue non-empty",
|
|
pcb->unacked != NULL || pcb->unsent != NULL);
|
|
} else {
|
|
LWIP_ASSERT("tcp_write: no pbufs on queue => both queues empty",
|
|
pcb->unacked == NULL && pcb->unsent == NULL);
|
|
}
|
|
return ERR_OK;
|
|
}
|
|
|
|
/**
|
|
* @ingroup tcp_raw
|
|
* Write data for sending (but does not send it immediately).
|
|
*
|
|
* It waits in the expectation of more data being sent soon (as
|
|
* it can send them more efficiently by combining them together).
|
|
* To prompt the system to send data now, call tcp_output() after
|
|
* calling tcp_write().
|
|
*
|
|
* This function enqueues the data pointed to by the argument dataptr. The length of
|
|
* the data is passed as the len parameter. The apiflags can be one or more of:
|
|
* - TCP_WRITE_FLAG_COPY: indicates whether the new memory should be allocated
|
|
* for the data to be copied into. If this flag is not given, no new memory
|
|
* should be allocated and the data should only be referenced by pointer. This
|
|
* also means that the memory behind dataptr must not change until the data is
|
|
* ACKed by the remote host
|
|
* - TCP_WRITE_FLAG_MORE: indicates that more data follows. If this is omitted,
|
|
* the PSH flag is set in the last segment created by this call to tcp_write.
|
|
* If this flag is given, the PSH flag is not set.
|
|
*
|
|
* The tcp_write() function will fail and return ERR_MEM if the length
|
|
* of the data exceeds the current send buffer size or if the length of
|
|
* the queue of outgoing segment is larger than the upper limit defined
|
|
* in lwipopts.h. The number of bytes available in the output queue can
|
|
* be retrieved with the tcp_sndbuf() function.
|
|
*
|
|
* The proper way to use this function is to call the function with at
|
|
* most tcp_sndbuf() bytes of data. If the function returns ERR_MEM,
|
|
* the application should wait until some of the currently enqueued
|
|
* data has been successfully received by the other host and try again.
|
|
*
|
|
* @param pcb Protocol control block for the TCP connection to enqueue data for.
|
|
* @param arg Pointer to the data to be enqueued for sending.
|
|
* @param len Data length in bytes
|
|
* @param apiflags combination of following flags :
|
|
* - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
|
|
* - TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will not be set on last segment sent,
|
|
* @return ERR_OK if enqueued, another err_t on error
|
|
*/
|
|
err_t
|
|
tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
|
|
{
|
|
struct pbuf *concat_p = NULL;
|
|
struct tcp_seg *last_unsent = NULL, *seg = NULL, *prev_seg = NULL, *queue = NULL;
|
|
u16_t pos = 0; /* position in 'arg' data */
|
|
u16_t queuelen;
|
|
u8_t optlen;
|
|
u8_t optflags = 0;
|
|
#if TCP_OVERSIZE
|
|
u16_t oversize = 0;
|
|
u16_t oversize_used = 0;
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
u16_t oversize_add = 0;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK*/
|
|
#endif /* TCP_OVERSIZE */
|
|
u16_t extendlen = 0;
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
u16_t concat_chksum = 0;
|
|
u8_t concat_chksum_swapped = 0;
|
|
u16_t concat_chksummed = 0;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
err_t err;
|
|
u16_t mss_local;
|
|
|
|
LWIP_ERROR("tcp_write: invalid pcb", pcb != NULL, return ERR_ARG);
|
|
|
|
/* don't allocate segments bigger than half the maximum window we ever received */
|
|
mss_local = LWIP_MIN(pcb->mss, TCPWND_MIN16(pcb->snd_wnd_max / 2));
|
|
mss_local = mss_local ? mss_local : pcb->mss;
|
|
|
|
LWIP_ASSERT_CORE_LOCKED();
|
|
|
|
#if LWIP_NETIF_TX_SINGLE_PBUF
|
|
/* Always copy to try to create single pbufs for TX */
|
|
apiflags |= TCP_WRITE_FLAG_COPY;
|
|
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
|
|
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_write(pcb=%p, data=%p, len=%"U16_F", apiflags=%"U16_F")\n",
|
|
(void *)pcb, arg, len, (u16_t)apiflags));
|
|
LWIP_ERROR("tcp_write: arg == NULL (programmer violates API)",
|
|
arg != NULL, return ERR_ARG;);
|
|
|
|
err = tcp_write_checks(pcb, len);
|
|
if (err != ERR_OK) {
|
|
return err;
|
|
}
|
|
queuelen = pcb->snd_queuelen;
|
|
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
if ((pcb->flags & TF_TIMESTAMP)) {
|
|
/* Make sure the timestamp option is only included in data segments if we
|
|
agreed about it with the remote host. */
|
|
optflags = TF_SEG_OPTS_TS;
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(TF_SEG_OPTS_TS, pcb);
|
|
/* ensure that segments can hold at least one data byte... */
|
|
mss_local = LWIP_MAX(mss_local, LWIP_TCP_OPT_LEN_TS + 1);
|
|
} else
|
|
#endif /* LWIP_TCP_TIMESTAMPS */
|
|
{
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
|
}
|
|
|
|
|
|
/*
|
|
* TCP segmentation is done in three phases with increasing complexity:
|
|
*
|
|
* 1. Copy data directly into an oversized pbuf.
|
|
* 2. Chain a new pbuf to the end of pcb->unsent.
|
|
* 3. Create new segments.
|
|
*
|
|
* We may run out of memory at any point. In that case we must
|
|
* return ERR_MEM and not change anything in pcb. Therefore, all
|
|
* changes are recorded in local variables and committed at the end
|
|
* of the function. Some pcb fields are maintained in local copies:
|
|
*
|
|
* queuelen = pcb->snd_queuelen
|
|
* oversize = pcb->unsent_oversize
|
|
*
|
|
* These variables are set consistently by the phases:
|
|
*
|
|
* seg points to the last segment tampered with.
|
|
*
|
|
* pos records progress as data is segmented.
|
|
*/
|
|
|
|
/* Find the tail of the unsent queue. */
|
|
if (pcb->unsent != NULL) {
|
|
u16_t space;
|
|
u16_t unsent_optlen;
|
|
|
|
/* @todo: this could be sped up by keeping last_unsent in the pcb */
|
|
for (last_unsent = pcb->unsent; last_unsent->next != NULL;
|
|
last_unsent = last_unsent->next);
|
|
|
|
/* Usable space at the end of the last unsent segment */
|
|
unsent_optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(last_unsent->flags, pcb);
|
|
LWIP_ASSERT("mss_local is too small", mss_local >= last_unsent->len + unsent_optlen);
|
|
space = mss_local - (last_unsent->len + unsent_optlen);
|
|
|
|
/*
|
|
* Phase 1: Copy data directly into an oversized pbuf.
|
|
*
|
|
* The number of bytes copied is recorded in the oversize_used
|
|
* variable. The actual copying is done at the bottom of the
|
|
* function.
|
|
*/
|
|
#if TCP_OVERSIZE
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
/* check that pcb->unsent_oversize matches last_unsent->oversize_left */
|
|
LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
|
|
pcb->unsent_oversize == last_unsent->oversize_left);
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
oversize = pcb->unsent_oversize;
|
|
if (oversize > 0) {
|
|
LWIP_ASSERT("inconsistent oversize vs. space", oversize <= space);
|
|
seg = last_unsent;
|
|
oversize_used = LWIP_MIN(space, LWIP_MIN(oversize, len));
|
|
pos += oversize_used;
|
|
oversize -= oversize_used;
|
|
space -= oversize_used;
|
|
}
|
|
/* now we are either finished or oversize is zero */
|
|
LWIP_ASSERT("inconsistent oversize vs. len", (oversize == 0) || (pos == len));
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
#if !LWIP_NETIF_TX_SINGLE_PBUF
|
|
/*
|
|
* Phase 2: Chain a new pbuf to the end of pcb->unsent.
|
|
*
|
|
* As an exception when NOT copying the data, if the given data buffer
|
|
* directly follows the last unsent data buffer in memory, extend the last
|
|
* ROM pbuf reference to the buffer, thus saving a ROM pbuf allocation.
|
|
*
|
|
* We don't extend segments containing SYN/FIN flags or options
|
|
* (len==0). The new pbuf is kept in concat_p and pbuf_cat'ed at
|
|
* the end.
|
|
*
|
|
* This phase is skipped for LWIP_NETIF_TX_SINGLE_PBUF as we could only execute
|
|
* it after rexmit puts a segment from unacked to unsent and at this point,
|
|
* oversize info is lost.
|
|
*/
|
|
if ((pos < len) && (space > 0) && (last_unsent->len > 0)) {
|
|
u16_t seglen = LWIP_MIN(space, len - pos);
|
|
seg = last_unsent;
|
|
|
|
/* Create a pbuf with a copy or reference to seglen bytes. We
|
|
* can use PBUF_RAW here since the data appears in the middle of
|
|
* a segment. A header will never be prepended. */
|
|
if (apiflags & TCP_WRITE_FLAG_COPY) {
|
|
/* Data is copied */
|
|
if ((concat_p = tcp_pbuf_prealloc(PBUF_RAW, seglen, space, &oversize, pcb, apiflags, 1)) == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
|
("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n",
|
|
seglen));
|
|
goto memerr;
|
|
}
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
oversize_add = oversize;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
TCP_DATA_COPY2(concat_p->payload, (const u8_t *)arg + pos, seglen, &concat_chksum, &concat_chksum_swapped);
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
concat_chksummed += seglen;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
queuelen += pbuf_clen(concat_p);
|
|
} else {
|
|
/* Data is not copied */
|
|
/* If the last unsent pbuf is of type PBUF_ROM, try to extend it. */
|
|
struct pbuf *p;
|
|
for (p = last_unsent->p; p->next != NULL; p = p->next);
|
|
if (((p->type_internal & (PBUF_TYPE_FLAG_STRUCT_DATA_CONTIGUOUS | PBUF_TYPE_FLAG_DATA_VOLATILE)) == 0) &&
|
|
(const u8_t *)p->payload + p->len == (const u8_t *)arg) {
|
|
LWIP_ASSERT("tcp_write: ROM pbufs cannot be oversized", pos == 0);
|
|
extendlen = seglen;
|
|
} else {
|
|
if ((concat_p = pbuf_alloc(PBUF_RAW, seglen, PBUF_ROM)) == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
|
("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
|
goto memerr;
|
|
}
|
|
/* reference the non-volatile payload data */
|
|
((struct pbuf_rom *)concat_p)->payload = (const u8_t *)arg + pos;
|
|
queuelen += pbuf_clen(concat_p);
|
|
}
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/* calculate the checksum of nocopy-data */
|
|
tcp_seg_add_chksum(~inet_chksum((const u8_t *)arg + pos, seglen), seglen,
|
|
&concat_chksum, &concat_chksum_swapped);
|
|
concat_chksummed += seglen;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
}
|
|
|
|
pos += seglen;
|
|
}
|
|
#endif /* !LWIP_NETIF_TX_SINGLE_PBUF */
|
|
} else {
|
|
#if TCP_OVERSIZE
|
|
LWIP_ASSERT("unsent_oversize mismatch (pcb->unsent is NULL)",
|
|
pcb->unsent_oversize == 0);
|
|
#endif /* TCP_OVERSIZE */
|
|
}
|
|
|
|
/*
|
|
* Phase 3: Create new segments.
|
|
*
|
|
* The new segments are chained together in the local 'queue'
|
|
* variable, ready to be appended to pcb->unsent.
|
|
*/
|
|
while (pos < len) {
|
|
struct pbuf *p;
|
|
u16_t left = len - pos;
|
|
u16_t max_len = mss_local - optlen;
|
|
u16_t seglen = LWIP_MIN(left, max_len);
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
u16_t chksum = 0;
|
|
u8_t chksum_swapped = 0;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
if (apiflags & TCP_WRITE_FLAG_COPY) {
|
|
/* If copy is set, memory should be allocated and data copied
|
|
* into pbuf */
|
|
if ((p = tcp_pbuf_prealloc(PBUF_TRANSPORT, seglen + optlen, mss_local, &oversize, pcb, apiflags, queue == NULL)) == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write : could not allocate memory for pbuf copy size %"U16_F"\n", seglen));
|
|
goto memerr;
|
|
}
|
|
LWIP_ASSERT("tcp_write: check that first pbuf can hold the complete seglen",
|
|
(p->len >= seglen));
|
|
TCP_DATA_COPY2((char *)p->payload + optlen, (const u8_t *)arg + pos, seglen, &chksum, &chksum_swapped);
|
|
} else {
|
|
/* Copy is not set: First allocate a pbuf for holding the data.
|
|
* Since the referenced data is available at least until it is
|
|
* sent out on the link (as it has to be ACKed by the remote
|
|
* party) we can safely use PBUF_ROM instead of PBUF_REF here.
|
|
*/
|
|
struct pbuf *p2;
|
|
#if TCP_OVERSIZE
|
|
LWIP_ASSERT("oversize == 0", oversize == 0);
|
|
#endif /* TCP_OVERSIZE */
|
|
if ((p2 = pbuf_alloc(PBUF_TRANSPORT, seglen, PBUF_ROM)) == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: could not allocate memory for zero-copy pbuf\n"));
|
|
goto memerr;
|
|
}
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/* calculate the checksum of nocopy-data */
|
|
chksum = ~inet_chksum((const u8_t *)arg + pos, seglen);
|
|
if (seglen & 1) {
|
|
chksum_swapped = 1;
|
|
chksum = SWAP_BYTES_IN_WORD(chksum);
|
|
}
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
/* reference the non-volatile payload data */
|
|
((struct pbuf_rom *)p2)->payload = (const u8_t *)arg + pos;
|
|
|
|
/* Second, allocate a pbuf for the headers. */
|
|
if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
|
/* If allocation fails, we have to deallocate the data pbuf as
|
|
* well. */
|
|
pbuf_free(p2);
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: could not allocate memory for header pbuf\n"));
|
|
goto memerr;
|
|
}
|
|
/* Concatenate the headers and data pbufs together. */
|
|
pbuf_cat(p/*header*/, p2/*data*/);
|
|
}
|
|
|
|
queuelen += pbuf_clen(p);
|
|
|
|
/* Now that there are more segments queued, we check again if the
|
|
* length of the queue exceeds the configured maximum or
|
|
* overflows. */
|
|
if (queuelen > LWIP_MIN(TCP_SND_QUEUELEN, TCP_SNDQUEUELEN_OVERFLOW)) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_write: queue too long %"U16_F" (%d)\n",
|
|
queuelen, (int)TCP_SND_QUEUELEN));
|
|
pbuf_free(p);
|
|
goto memerr;
|
|
}
|
|
|
|
if ((seg = tcp_create_segment(pcb, p, 0, pcb->snd_lbb + pos, optflags)) == NULL) {
|
|
goto memerr;
|
|
}
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
seg->oversize_left = oversize;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
seg->chksum = chksum;
|
|
seg->chksum_swapped = chksum_swapped;
|
|
seg->flags |= TF_SEG_DATA_CHECKSUMMED;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/* first segment of to-be-queued data? */
|
|
if (queue == NULL) {
|
|
queue = seg;
|
|
} else {
|
|
/* Attach the segment to the end of the queued segments */
|
|
LWIP_ASSERT("prev_seg != NULL", prev_seg != NULL);
|
|
prev_seg->next = seg;
|
|
}
|
|
/* remember last segment of to-be-queued data for next iteration */
|
|
prev_seg = seg;
|
|
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE, ("tcp_write: queueing %"U32_F":%"U32_F"\n",
|
|
lwip_ntohl(seg->tcphdr->seqno),
|
|
lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg)));
|
|
|
|
pos += seglen;
|
|
}
|
|
|
|
/*
|
|
* All three segmentation phases were successful. We can commit the
|
|
* transaction.
|
|
*/
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
if ((last_unsent != NULL) && (oversize_add != 0)) {
|
|
last_unsent->oversize_left += oversize_add;
|
|
}
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
|
|
/*
|
|
* Phase 1: If data has been added to the preallocated tail of
|
|
* last_unsent, we update the length fields of the pbuf chain.
|
|
*/
|
|
#if TCP_OVERSIZE
|
|
if (oversize_used > 0) {
|
|
struct pbuf *p;
|
|
/* Bump tot_len of whole chain, len of tail */
|
|
for (p = last_unsent->p; p; p = p->next) {
|
|
p->tot_len += oversize_used;
|
|
if (p->next == NULL) {
|
|
TCP_DATA_COPY((char *)p->payload + p->len, arg, oversize_used, last_unsent);
|
|
p->len += oversize_used;
|
|
}
|
|
}
|
|
last_unsent->len += oversize_used;
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
LWIP_ASSERT("last_unsent->oversize_left >= oversize_used",
|
|
last_unsent->oversize_left >= oversize_used);
|
|
last_unsent->oversize_left -= oversize_used;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
}
|
|
pcb->unsent_oversize = oversize;
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
/*
|
|
* Phase 2: concat_p can be concatenated onto last_unsent->p, unless we
|
|
* determined that the last ROM pbuf can be extended to include the new data.
|
|
*/
|
|
if (concat_p != NULL) {
|
|
LWIP_ASSERT("tcp_write: cannot concatenate when pcb->unsent is empty",
|
|
(last_unsent != NULL));
|
|
pbuf_cat(last_unsent->p, concat_p);
|
|
last_unsent->len += concat_p->tot_len;
|
|
} else if (extendlen > 0) {
|
|
struct pbuf *p;
|
|
LWIP_ASSERT("tcp_write: extension of reference requires reference",
|
|
last_unsent != NULL && last_unsent->p != NULL);
|
|
for (p = last_unsent->p; p->next != NULL; p = p->next) {
|
|
p->tot_len += extendlen;
|
|
}
|
|
p->tot_len += extendlen;
|
|
p->len += extendlen;
|
|
last_unsent->len += extendlen;
|
|
}
|
|
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
if (concat_chksummed) {
|
|
LWIP_ASSERT("tcp_write: concat checksum needs concatenated data",
|
|
concat_p != NULL || extendlen > 0);
|
|
/*if concat checksumm swapped - swap it back */
|
|
if (concat_chksum_swapped) {
|
|
concat_chksum = SWAP_BYTES_IN_WORD(concat_chksum);
|
|
}
|
|
tcp_seg_add_chksum(concat_chksum, concat_chksummed, &last_unsent->chksum,
|
|
&last_unsent->chksum_swapped);
|
|
last_unsent->flags |= TF_SEG_DATA_CHECKSUMMED;
|
|
}
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/*
|
|
* Phase 3: Append queue to pcb->unsent. Queue may be NULL, but that
|
|
* is harmless
|
|
*/
|
|
if (last_unsent == NULL) {
|
|
pcb->unsent = queue;
|
|
} else {
|
|
last_unsent->next = queue;
|
|
}
|
|
|
|
/*
|
|
* Finally update the pcb state.
|
|
*/
|
|
pcb->snd_lbb += len;
|
|
pcb->snd_buf -= len;
|
|
pcb->snd_queuelen = queuelen;
|
|
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_write: %"S16_F" (after enqueued)\n",
|
|
pcb->snd_queuelen));
|
|
if (pcb->snd_queuelen != 0) {
|
|
LWIP_ASSERT("tcp_write: valid queue length",
|
|
pcb->unacked != NULL || pcb->unsent != NULL);
|
|
}
|
|
|
|
/* Set the PSH flag in the last segment that we enqueued. */
|
|
if (seg != NULL && seg->tcphdr != NULL && ((apiflags & TCP_WRITE_FLAG_MORE) == 0)) {
|
|
TCPH_SET_FLAG(seg->tcphdr, TCP_PSH);
|
|
}
|
|
|
|
return ERR_OK;
|
|
memerr:
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
TCP_STATS_INC(tcp.memerr);
|
|
|
|
if (concat_p != NULL) {
|
|
pbuf_free(concat_p);
|
|
}
|
|
if (queue != NULL) {
|
|
tcp_segs_free(queue);
|
|
}
|
|
if (pcb->snd_queuelen != 0) {
|
|
LWIP_ASSERT("tcp_write: valid queue length", pcb->unacked != NULL ||
|
|
pcb->unsent != NULL);
|
|
}
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG | LWIP_DBG_STATE, ("tcp_write: %"S16_F" (with mem err)\n", pcb->snd_queuelen));
|
|
return ERR_MEM;
|
|
}
|
|
|
|
/**
|
|
* Split segment on the head of the unsent queue. If return is not
|
|
* ERR_OK, existing head remains intact
|
|
*
|
|
* The split is accomplished by creating a new TCP segment and pbuf
|
|
* which holds the remainder payload after the split. The original
|
|
* pbuf is trimmed to new length. This allows splitting of read-only
|
|
* pbufs
|
|
*
|
|
* @param pcb the tcp_pcb for which to split the unsent head
|
|
* @param split the amount of payload to remain in the head
|
|
*/
|
|
err_t
|
|
tcp_split_unsent_seg(struct tcp_pcb *pcb, u16_t split)
|
|
{
|
|
struct tcp_seg *seg = NULL, *useg = NULL;
|
|
struct pbuf *p = NULL;
|
|
u8_t optlen;
|
|
u8_t optflags;
|
|
u8_t split_flags;
|
|
u8_t remainder_flags;
|
|
u16_t remainder;
|
|
u16_t offset;
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
u16_t chksum = 0;
|
|
u8_t chksum_swapped = 0;
|
|
struct pbuf *q;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
LWIP_ASSERT("tcp_split_unsent_seg: invalid pcb", pcb != NULL);
|
|
|
|
useg = pcb->unsent;
|
|
if (useg == NULL) {
|
|
return ERR_MEM;
|
|
}
|
|
|
|
if (split == 0) {
|
|
LWIP_ASSERT("Can't split segment into length 0", 0);
|
|
return ERR_VAL;
|
|
}
|
|
|
|
if (useg->len <= split) {
|
|
return ERR_OK;
|
|
}
|
|
|
|
LWIP_ASSERT("split <= mss", split <= pcb->mss);
|
|
LWIP_ASSERT("useg->len > 0", useg->len > 0);
|
|
|
|
/* We should check that we don't exceed TCP_SND_QUEUELEN but we need
|
|
* to split this packet so we may actually exceed the max value by
|
|
* one!
|
|
*/
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue: split_unsent_seg: %u\n", (unsigned int)pcb->snd_queuelen));
|
|
|
|
optflags = useg->flags;
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/* Remove since checksum is not stored until after tcp_create_segment() */
|
|
optflags &= ~TF_SEG_DATA_CHECKSUMMED;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
optlen = LWIP_TCP_OPT_LENGTH(optflags);
|
|
remainder = useg->len - split;
|
|
|
|
/* Create new pbuf for the remainder of the split */
|
|
p = pbuf_alloc(PBUF_TRANSPORT, remainder + optlen, PBUF_RAM);
|
|
if (p == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
|
("tcp_split_unsent_seg: could not allocate memory for pbuf remainder %u\n", remainder));
|
|
goto memerr;
|
|
}
|
|
|
|
/* Offset into the original pbuf is past TCP/IP headers, options, and split amount */
|
|
offset = useg->p->tot_len - useg->len + split;
|
|
/* Copy remainder into new pbuf, headers and options will not be filled out */
|
|
if (pbuf_copy_partial(useg->p, (u8_t *)p->payload + optlen, remainder, offset ) != remainder) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
|
("tcp_split_unsent_seg: could not copy pbuf remainder %u\n", remainder));
|
|
goto memerr;
|
|
}
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/* calculate the checksum on remainder data */
|
|
tcp_seg_add_chksum(~inet_chksum((const u8_t *)p->payload + optlen, remainder), remainder,
|
|
&chksum, &chksum_swapped);
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/* Options are created when calling tcp_output() */
|
|
|
|
/* Migrate flags from original segment */
|
|
split_flags = TCPH_FLAGS(useg->tcphdr);
|
|
remainder_flags = 0; /* ACK added in tcp_output() */
|
|
|
|
if (split_flags & TCP_PSH) {
|
|
split_flags &= ~TCP_PSH;
|
|
remainder_flags |= TCP_PSH;
|
|
}
|
|
if (split_flags & TCP_FIN) {
|
|
split_flags &= ~TCP_FIN;
|
|
remainder_flags |= TCP_FIN;
|
|
}
|
|
/* SYN should be left on split, RST should not be present with data */
|
|
|
|
seg = tcp_create_segment(pcb, p, remainder_flags, lwip_ntohl(useg->tcphdr->seqno) + split, optflags);
|
|
if (seg == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_LEVEL_SERIOUS,
|
|
("tcp_split_unsent_seg: could not create new TCP segment\n"));
|
|
goto memerr;
|
|
}
|
|
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
seg->chksum = chksum;
|
|
seg->chksum_swapped = chksum_swapped;
|
|
seg->flags |= TF_SEG_DATA_CHECKSUMMED;
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/* Remove this segment from the queue since trimming it may free pbufs */
|
|
pcb->snd_queuelen -= pbuf_clen(useg->p);
|
|
|
|
/* Trim the original pbuf into our split size. At this point our remainder segment must be setup
|
|
successfully because we are modifying the original segment */
|
|
pbuf_realloc(useg->p, useg->p->tot_len - remainder);
|
|
useg->len -= remainder;
|
|
TCPH_SET_FLAG(useg->tcphdr, split_flags);
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
/* By trimming, realloc may have actually shrunk the pbuf, so clear oversize_left */
|
|
useg->oversize_left = 0;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
|
|
/* Add back to the queue with new trimmed pbuf */
|
|
pcb->snd_queuelen += pbuf_clen(useg->p);
|
|
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
/* The checksum on the split segment is now incorrect. We need to re-run it over the split */
|
|
useg->chksum = 0;
|
|
useg->chksum_swapped = 0;
|
|
q = useg->p;
|
|
offset = q->tot_len - useg->len; /* Offset due to exposed headers */
|
|
|
|
/* Advance to the pbuf where the offset ends */
|
|
while (q != NULL && offset > q->len) {
|
|
offset -= q->len;
|
|
q = q->next;
|
|
}
|
|
LWIP_ASSERT("Found start of payload pbuf", q != NULL);
|
|
/* Checksum the first payload pbuf accounting for offset, then other pbufs are all payload */
|
|
for (; q != NULL; offset = 0, q = q->next) {
|
|
tcp_seg_add_chksum(~inet_chksum((const u8_t *)q->payload + offset, q->len - offset), q->len - offset,
|
|
&useg->chksum, &useg->chksum_swapped);
|
|
}
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
|
|
/* Update number of segments on the queues. Note that length now may
|
|
* exceed TCP_SND_QUEUELEN! We don't have to touch pcb->snd_buf
|
|
* because the total amount of data is constant when packet is split */
|
|
pcb->snd_queuelen += pbuf_clen(seg->p);
|
|
|
|
/* Finally insert remainder into queue after split (which stays head) */
|
|
seg->next = useg->next;
|
|
useg->next = seg;
|
|
|
|
#if TCP_OVERSIZE
|
|
/* If remainder is last segment on the unsent, ensure we clear the oversize amount
|
|
* because the remainder is always sized to the exact remaining amount */
|
|
if (seg->next == NULL) {
|
|
pcb->unsent_oversize = 0;
|
|
}
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
return ERR_OK;
|
|
memerr:
|
|
TCP_STATS_INC(tcp.memerr);
|
|
|
|
LWIP_ASSERT("seg == NULL", seg == NULL);
|
|
if (p != NULL) {
|
|
pbuf_free(p);
|
|
}
|
|
|
|
return ERR_MEM;
|
|
}
|
|
|
|
/**
|
|
* Called by tcp_close() to send a segment including FIN flag but not data.
|
|
* This FIN may be added to an existing segment or a new, otherwise empty
|
|
* segment is enqueued.
|
|
*
|
|
* @param pcb the tcp_pcb over which to send a segment
|
|
* @return ERR_OK if sent, another err_t otherwise
|
|
*/
|
|
err_t
|
|
tcp_send_fin(struct tcp_pcb *pcb)
|
|
{
|
|
LWIP_ASSERT("tcp_send_fin: invalid pcb", pcb != NULL);
|
|
|
|
/* first, try to add the fin to the last unsent segment */
|
|
if (pcb->unsent != NULL) {
|
|
struct tcp_seg *last_unsent;
|
|
for (last_unsent = pcb->unsent; last_unsent->next != NULL;
|
|
last_unsent = last_unsent->next);
|
|
|
|
if ((TCPH_FLAGS(last_unsent->tcphdr) & (TCP_SYN | TCP_FIN | TCP_RST)) == 0) {
|
|
/* no SYN/FIN/RST flag in the header, we can add the FIN flag */
|
|
TCPH_SET_FLAG(last_unsent->tcphdr, TCP_FIN);
|
|
tcp_set_flags(pcb, TF_FIN);
|
|
return ERR_OK;
|
|
}
|
|
}
|
|
/* no data, no length, flags, copy=1, no optdata */
|
|
return tcp_enqueue_flags(pcb, TCP_FIN);
|
|
}
|
|
|
|
/**
|
|
* Enqueue SYN or FIN for transmission.
|
|
*
|
|
* Called by @ref tcp_connect, tcp_listen_input, and @ref tcp_close
|
|
* (via @ref tcp_send_fin)
|
|
*
|
|
* @param pcb Protocol control block for the TCP connection.
|
|
* @param flags TCP header flags to set in the outgoing segment.
|
|
*/
|
|
err_t
|
|
tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags)
|
|
{
|
|
struct pbuf *p;
|
|
struct tcp_seg *seg;
|
|
u8_t optflags = 0;
|
|
u8_t optlen = 0;
|
|
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: queuelen: %"U16_F"\n", (u16_t)pcb->snd_queuelen));
|
|
|
|
LWIP_ASSERT("tcp_enqueue_flags: need either TCP_SYN or TCP_FIN in flags (programmer violates API)",
|
|
(flags & (TCP_SYN | TCP_FIN)) != 0);
|
|
LWIP_ASSERT("tcp_enqueue_flags: invalid pcb", pcb != NULL);
|
|
|
|
/* No need to check pcb->snd_queuelen if only SYN or FIN are allowed! */
|
|
|
|
/* Get options for this segment. This is a special case since this is the
|
|
only place where a SYN can be sent. */
|
|
if (flags & TCP_SYN) {
|
|
optflags = TF_SEG_OPTS_MSS;
|
|
#if LWIP_WND_SCALE
|
|
if ((pcb->state != SYN_RCVD) || (pcb->flags & TF_WND_SCALE)) {
|
|
/* In a <SYN,ACK> (sent in state SYN_RCVD), the window scale option may only
|
|
be sent if we received a window scale option from the remote host. */
|
|
optflags |= TF_SEG_OPTS_WND_SCALE;
|
|
}
|
|
#endif /* LWIP_WND_SCALE */
|
|
#if LWIP_TCP_SACK_OUT
|
|
if ((pcb->state != SYN_RCVD) || (pcb->flags & TF_SACK)) {
|
|
/* In a <SYN,ACK> (sent in state SYN_RCVD), the SACK_PERM option may only
|
|
be sent if we received a SACK_PERM option from the remote host. */
|
|
optflags |= TF_SEG_OPTS_SACK_PERM;
|
|
}
|
|
#endif /* LWIP_TCP_SACK_OUT */
|
|
}
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
if ((pcb->flags & TF_TIMESTAMP) || ((flags & TCP_SYN) && (pcb->state != SYN_RCVD))) {
|
|
/* Make sure the timestamp option is only included in data segments if we
|
|
agreed about it with the remote host (and in active open SYN segments). */
|
|
optflags |= TF_SEG_OPTS_TS;
|
|
}
|
|
#endif /* LWIP_TCP_TIMESTAMPS */
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
|
|
|
|
/* Allocate pbuf with room for TCP header + options */
|
|
if ((p = pbuf_alloc(PBUF_TRANSPORT, optlen, PBUF_RAM)) == NULL) {
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
TCP_STATS_INC(tcp.memerr);
|
|
return ERR_MEM;
|
|
}
|
|
LWIP_ASSERT("tcp_enqueue_flags: check that first pbuf can hold optlen",
|
|
(p->len >= optlen));
|
|
|
|
/* Allocate memory for tcp_seg, and fill in fields. */
|
|
if ((seg = tcp_create_segment(pcb, p, flags, pcb->snd_lbb, optflags)) == NULL) {
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
TCP_STATS_INC(tcp.memerr);
|
|
return ERR_MEM;
|
|
}
|
|
LWIP_ASSERT("seg->tcphdr not aligned", ((mem_ptr_t)seg->tcphdr % LWIP_MIN(MEM_ALIGNMENT, 4)) == 0);
|
|
LWIP_ASSERT("tcp_enqueue_flags: invalid segment length", seg->len == 0);
|
|
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG | LWIP_DBG_TRACE,
|
|
("tcp_enqueue_flags: queueing %"U32_F":%"U32_F" (0x%"X16_F")\n",
|
|
lwip_ntohl(seg->tcphdr->seqno),
|
|
lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg),
|
|
(u16_t)flags));
|
|
|
|
/* Now append seg to pcb->unsent queue */
|
|
if (pcb->unsent == NULL) {
|
|
pcb->unsent = seg;
|
|
} else {
|
|
struct tcp_seg *useg;
|
|
for (useg = pcb->unsent; useg->next != NULL; useg = useg->next);
|
|
useg->next = seg;
|
|
}
|
|
#if TCP_OVERSIZE
|
|
/* The new unsent tail has no space */
|
|
pcb->unsent_oversize = 0;
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
/* SYN and FIN bump the sequence number */
|
|
if ((flags & TCP_SYN) || (flags & TCP_FIN)) {
|
|
pcb->snd_lbb++;
|
|
/* optlen does not influence snd_buf */
|
|
}
|
|
if (flags & TCP_FIN) {
|
|
tcp_set_flags(pcb, TF_FIN);
|
|
}
|
|
|
|
/* update number of segments on the queues */
|
|
pcb->snd_queuelen += pbuf_clen(seg->p);
|
|
LWIP_DEBUGF(TCP_QLEN_DEBUG, ("tcp_enqueue_flags: %"S16_F" (after enqueued)\n", pcb->snd_queuelen));
|
|
if (pcb->snd_queuelen != 0) {
|
|
LWIP_ASSERT("tcp_enqueue_flags: invalid queue length",
|
|
pcb->unacked != NULL || pcb->unsent != NULL);
|
|
}
|
|
|
|
return ERR_OK;
|
|
}
|
|
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
/* Build a timestamp option (12 bytes long) at the specified options pointer)
|
|
*
|
|
* @param pcb tcp_pcb
|
|
* @param opts option pointer where to store the timestamp option
|
|
*/
|
|
static void
|
|
tcp_build_timestamp_option(const struct tcp_pcb *pcb, u32_t *opts)
|
|
{
|
|
LWIP_ASSERT("tcp_build_timestamp_option: invalid pcb", pcb != NULL);
|
|
|
|
/* Pad with two NOP options to make everything nicely aligned */
|
|
opts[0] = PP_HTONL(0x0101080A);
|
|
opts[1] = lwip_htonl(sys_now());
|
|
opts[2] = lwip_htonl(pcb->ts_recent);
|
|
}
|
|
#endif
|
|
|
|
#if LWIP_TCP_SACK_OUT
|
|
/**
|
|
* Calculates the number of SACK entries that should be generated.
|
|
* It takes into account whether TF_SACK flag is set,
|
|
* the number of SACK entries in tcp_pcb that are valid,
|
|
* as well as the available options size.
|
|
*
|
|
* @param pcb tcp_pcb
|
|
* @param optlen the length of other TCP options (in bytes)
|
|
* @return the number of SACK ranges that can be used
|
|
*/
|
|
static u8_t
|
|
tcp_get_num_sacks(const struct tcp_pcb *pcb, u8_t optlen)
|
|
{
|
|
u8_t num_sacks = 0;
|
|
|
|
LWIP_ASSERT("tcp_get_num_sacks: invalid pcb", pcb != NULL);
|
|
|
|
if (pcb->flags & TF_SACK) {
|
|
u8_t i;
|
|
|
|
/* The first SACK takes up 12 bytes (it includes SACK header and two NOP options),
|
|
each additional one - 8 bytes. */
|
|
optlen += 12;
|
|
|
|
/* Max options size = 40, number of SACK array entries = LWIP_TCP_MAX_SACK_NUM */
|
|
for (i = 0; (i < LWIP_TCP_MAX_SACK_NUM) && (optlen <= TCP_MAX_OPTION_BYTES) &&
|
|
LWIP_TCP_SACK_VALID(pcb, i); ++i) {
|
|
++num_sacks;
|
|
optlen += 8;
|
|
}
|
|
}
|
|
|
|
return num_sacks;
|
|
}
|
|
|
|
/** Build a SACK option (12 or more bytes long) at the specified options pointer)
|
|
*
|
|
* @param pcb tcp_pcb
|
|
* @param opts option pointer where to store the SACK option
|
|
* @param num_sacks the number of SACKs to store
|
|
*/
|
|
static void
|
|
tcp_build_sack_option(const struct tcp_pcb *pcb, u32_t *opts, u8_t num_sacks)
|
|
{
|
|
u8_t i;
|
|
|
|
LWIP_ASSERT("tcp_build_sack_option: invalid pcb", pcb != NULL);
|
|
LWIP_ASSERT("tcp_build_sack_option: invalid opts", opts != NULL);
|
|
|
|
/* Pad with two NOP options to make everything nicely aligned.
|
|
We add the length (of just the SACK option, not the NOPs in front of it),
|
|
which is 2B of header, plus 8B for each SACK. */
|
|
*(opts++) = PP_HTONL(0x01010500 + 2 + num_sacks * 8);
|
|
|
|
for (i = 0; i < num_sacks; ++i) {
|
|
*(opts++) = lwip_htonl(pcb->rcv_sacks[i].left);
|
|
*(opts++) = lwip_htonl(pcb->rcv_sacks[i].right);
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
#if LWIP_WND_SCALE
|
|
/** Build a window scale option (3 bytes long) at the specified options pointer)
|
|
*
|
|
* @param opts option pointer where to store the window scale option
|
|
*/
|
|
static void
|
|
tcp_build_wnd_scale_option(u32_t *opts)
|
|
{
|
|
LWIP_ASSERT("tcp_build_wnd_scale_option: invalid opts", opts != NULL);
|
|
|
|
/* Pad with one NOP option to make everything nicely aligned */
|
|
opts[0] = PP_HTONL(0x01030300 | TCP_RCV_SCALE);
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* @ingroup tcp_raw
|
|
* Find out what we can send and send it
|
|
*
|
|
* @param pcb Protocol control block for the TCP connection to send data
|
|
* @return ERR_OK if data has been sent or nothing to send
|
|
* another err_t on error
|
|
*/
|
|
err_t
|
|
tcp_output(struct tcp_pcb *pcb)
|
|
{
|
|
struct tcp_seg *seg, *useg;
|
|
u32_t wnd, snd_nxt;
|
|
err_t err;
|
|
struct netif *netif;
|
|
#if TCP_CWND_DEBUG
|
|
s16_t i = 0;
|
|
#endif /* TCP_CWND_DEBUG */
|
|
|
|
LWIP_ASSERT_CORE_LOCKED();
|
|
|
|
LWIP_ASSERT("tcp_output: invalid pcb", pcb != NULL);
|
|
/* pcb->state LISTEN not allowed here */
|
|
LWIP_ASSERT("don't call tcp_output for listen-pcbs",
|
|
pcb->state != LISTEN);
|
|
|
|
/* First, check if we are invoked by the TCP input processing
|
|
code. If so, we do not output anything. Instead, we rely on the
|
|
input processing code to call us when input processing is done
|
|
with. */
|
|
if (tcp_input_pcb == pcb) {
|
|
return ERR_OK;
|
|
}
|
|
|
|
wnd = LWIP_MIN(pcb->snd_wnd, pcb->cwnd);
|
|
|
|
seg = pcb->unsent;
|
|
|
|
if (seg == NULL) {
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: nothing to send (%p)\n",
|
|
(void *)pcb->unsent));
|
|
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"TCPWNDSIZE_F
|
|
", cwnd %"TCPWNDSIZE_F", wnd %"U32_F
|
|
", seg == NULL, ack %"U32_F"\n",
|
|
pcb->snd_wnd, pcb->cwnd, wnd, pcb->lastack));
|
|
|
|
/* If the TF_ACK_NOW flag is set and the ->unsent queue is empty, construct
|
|
* an empty ACK segment and send it. */
|
|
if (pcb->flags & TF_ACK_NOW) {
|
|
return tcp_send_empty_ack(pcb);
|
|
}
|
|
/* nothing to send: shortcut out of here */
|
|
goto output_done;
|
|
} else {
|
|
LWIP_DEBUGF(TCP_CWND_DEBUG,
|
|
("tcp_output: snd_wnd %"TCPWNDSIZE_F", cwnd %"TCPWNDSIZE_F", wnd %"U32_F
|
|
", effwnd %"U32_F", seq %"U32_F", ack %"U32_F"\n",
|
|
pcb->snd_wnd, pcb->cwnd, wnd,
|
|
lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len,
|
|
lwip_ntohl(seg->tcphdr->seqno), pcb->lastack));
|
|
}
|
|
|
|
netif = tcp_route(pcb, &pcb->local_ip, &pcb->remote_ip);
|
|
if (netif == NULL) {
|
|
return ERR_RTE;
|
|
}
|
|
|
|
/* If we don't have a local IP address, we get one from netif */
|
|
if (ip_addr_isany(&pcb->local_ip)) {
|
|
const ip_addr_t *local_ip = ip_netif_get_local_ip(netif, &pcb->remote_ip);
|
|
if (local_ip == NULL) {
|
|
return ERR_RTE;
|
|
}
|
|
ip_addr_copy(pcb->local_ip, *local_ip);
|
|
}
|
|
|
|
/* Handle the current segment not fitting within the window */
|
|
if (lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len > wnd) {
|
|
/* We need to start the persistent timer when the next unsent segment does not fit
|
|
* within the remaining (could be 0) send window and RTO timer is not running (we
|
|
* have no in-flight data). If window is still too small after persist timer fires,
|
|
* then we split the segment. We don't consider the congestion window since a cwnd
|
|
* smaller than 1 SMSS implies in-flight data
|
|
*/
|
|
if (wnd == pcb->snd_wnd && pcb->unacked == NULL && pcb->persist_backoff == 0) {
|
|
pcb->persist_cnt = 0;
|
|
pcb->persist_backoff = 1;
|
|
pcb->persist_probe = 0;
|
|
}
|
|
/* We need an ACK, but can't send data now, so send an empty ACK */
|
|
if (pcb->flags & TF_ACK_NOW) {
|
|
return tcp_send_empty_ack(pcb);
|
|
}
|
|
goto output_done;
|
|
}
|
|
/* Stop persist timer, above conditions are not active */
|
|
pcb->persist_backoff = 0;
|
|
|
|
/* useg should point to last segment on unacked queue */
|
|
useg = pcb->unacked;
|
|
if (useg != NULL) {
|
|
for (; useg->next != NULL; useg = useg->next);
|
|
}
|
|
/* data available and window allows it to be sent? */
|
|
while (seg != NULL &&
|
|
lwip_ntohl(seg->tcphdr->seqno) - pcb->lastack + seg->len <= wnd) {
|
|
LWIP_ASSERT("RST not expected here!",
|
|
(TCPH_FLAGS(seg->tcphdr) & TCP_RST) == 0);
|
|
/* Stop sending if the nagle algorithm would prevent it
|
|
* Don't stop:
|
|
* - if tcp_write had a memory error before (prevent delayed ACK timeout) or
|
|
* - if FIN was already enqueued for this PCB (SYN is always alone in a segment -
|
|
* either seg->next != NULL or pcb->unacked == NULL;
|
|
* RST is no sent using tcp_write/tcp_output.
|
|
*/
|
|
if ((tcp_do_output_nagle(pcb) == 0) &&
|
|
((pcb->flags & (TF_NAGLEMEMERR | TF_FIN)) == 0)) {
|
|
break;
|
|
}
|
|
#if TCP_CWND_DEBUG
|
|
LWIP_DEBUGF(TCP_CWND_DEBUG, ("tcp_output: snd_wnd %"TCPWNDSIZE_F", cwnd %"TCPWNDSIZE_F", wnd %"U32_F", effwnd %"U32_F", seq %"U32_F", ack %"U32_F", i %"S16_F"\n",
|
|
pcb->snd_wnd, pcb->cwnd, wnd,
|
|
lwip_ntohl(seg->tcphdr->seqno) + seg->len -
|
|
pcb->lastack,
|
|
lwip_ntohl(seg->tcphdr->seqno), pcb->lastack, i));
|
|
++i;
|
|
#endif /* TCP_CWND_DEBUG */
|
|
|
|
if (pcb->state != SYN_SENT) {
|
|
TCPH_SET_FLAG(seg->tcphdr, TCP_ACK);
|
|
}
|
|
|
|
err = tcp_output_segment(seg, pcb, netif);
|
|
if (err != ERR_OK) {
|
|
/* segment could not be sent, for whatever reason */
|
|
tcp_set_flags(pcb, TF_NAGLEMEMERR);
|
|
return err;
|
|
}
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
seg->oversize_left = 0;
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
pcb->unsent = seg->next;
|
|
if (pcb->state != SYN_SENT) {
|
|
tcp_clear_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
|
}
|
|
snd_nxt = lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
|
|
if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
|
pcb->snd_nxt = snd_nxt;
|
|
}
|
|
/* put segment on unacknowledged list if length > 0 */
|
|
if (TCP_TCPLEN(seg) > 0) {
|
|
seg->next = NULL;
|
|
/* unacked list is empty? */
|
|
if (pcb->unacked == NULL) {
|
|
pcb->unacked = seg;
|
|
useg = seg;
|
|
/* unacked list is not empty? */
|
|
} else {
|
|
/* In the case of fast retransmit, the packet should not go to the tail
|
|
* of the unacked queue, but rather somewhere before it. We need to check for
|
|
* this case. -STJ Jul 27, 2004 */
|
|
if (TCP_SEQ_LT(lwip_ntohl(seg->tcphdr->seqno), lwip_ntohl(useg->tcphdr->seqno))) {
|
|
/* add segment to before tail of unacked list, keeping the list sorted */
|
|
struct tcp_seg **cur_seg = &(pcb->unacked);
|
|
while (*cur_seg &&
|
|
TCP_SEQ_LT(lwip_ntohl((*cur_seg)->tcphdr->seqno), lwip_ntohl(seg->tcphdr->seqno))) {
|
|
cur_seg = &((*cur_seg)->next );
|
|
}
|
|
seg->next = (*cur_seg);
|
|
(*cur_seg) = seg;
|
|
} else {
|
|
/* add segment to tail of unacked list */
|
|
useg->next = seg;
|
|
useg = useg->next;
|
|
}
|
|
}
|
|
/* do not queue empty segments on the unacked list */
|
|
} else {
|
|
tcp_seg_free(seg);
|
|
}
|
|
seg = pcb->unsent;
|
|
}
|
|
#if TCP_OVERSIZE
|
|
if (pcb->unsent == NULL) {
|
|
/* last unsent has been removed, reset unsent_oversize */
|
|
pcb->unsent_oversize = 0;
|
|
}
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
output_done:
|
|
tcp_clear_flags(pcb, TF_NAGLEMEMERR);
|
|
return ERR_OK;
|
|
}
|
|
|
|
/** Check if a segment's pbufs are used by someone else than TCP.
|
|
* This can happen on retransmission if the pbuf of this segment is still
|
|
* referenced by the netif driver due to deferred transmission.
|
|
* This is the case (only!) if someone down the TX call path called
|
|
* pbuf_ref() on one of the pbufs!
|
|
*
|
|
* @arg seg the tcp segment to check
|
|
* @return 1 if ref != 1, 0 if ref == 1
|
|
*/
|
|
static int
|
|
tcp_output_segment_busy(const struct tcp_seg *seg)
|
|
{
|
|
LWIP_ASSERT("tcp_output_segment_busy: invalid seg", seg != NULL);
|
|
|
|
/* We only need to check the first pbuf here:
|
|
If a pbuf is queued for transmission, a driver calls pbuf_ref(),
|
|
which only changes the ref count of the first pbuf */
|
|
if (seg->p->ref != 1) {
|
|
/* other reference found */
|
|
return 1;
|
|
}
|
|
/* no other references found */
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Called by tcp_output() to actually send a TCP segment over IP.
|
|
*
|
|
* @param seg the tcp_seg to send
|
|
* @param pcb the tcp_pcb for the TCP connection used to send the segment
|
|
* @param netif the netif used to send the segment
|
|
*/
|
|
static err_t
|
|
tcp_output_segment(struct tcp_seg *seg, struct tcp_pcb *pcb, struct netif *netif)
|
|
{
|
|
err_t err;
|
|
u16_t len;
|
|
u32_t *opts;
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
int seg_chksum_was_swapped = 0;
|
|
#endif
|
|
|
|
LWIP_ASSERT("tcp_output_segment: invalid seg", seg != NULL);
|
|
LWIP_ASSERT("tcp_output_segment: invalid pcb", pcb != NULL);
|
|
LWIP_ASSERT("tcp_output_segment: invalid netif", netif != NULL);
|
|
|
|
if (tcp_output_segment_busy(seg)) {
|
|
/* This should not happen: rexmit functions should have checked this.
|
|
However, since this function modifies p->len, we must not continue in this case. */
|
|
LWIP_DEBUGF(TCP_RTO_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("tcp_output_segment: segment busy\n"));
|
|
return ERR_OK;
|
|
}
|
|
|
|
/* The TCP header has already been constructed, but the ackno and
|
|
wnd fields remain. */
|
|
seg->tcphdr->ackno = lwip_htonl(pcb->rcv_nxt);
|
|
|
|
/* advertise our receive window size in this TCP segment */
|
|
#if LWIP_WND_SCALE
|
|
if (seg->flags & TF_SEG_OPTS_WND_SCALE) {
|
|
/* The Window field in a SYN segment itself (the only type where we send
|
|
the window scale option) is never scaled. */
|
|
seg->tcphdr->wnd = lwip_htons(TCPWND_MIN16(pcb->rcv_ann_wnd));
|
|
} else
|
|
#endif /* LWIP_WND_SCALE */
|
|
{
|
|
seg->tcphdr->wnd = lwip_htons(TCPWND_MIN16(RCV_WND_SCALE(pcb, pcb->rcv_ann_wnd)));
|
|
}
|
|
|
|
pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
|
|
|
|
/* Add any requested options. NB MSS option is only set on SYN
|
|
packets, so ignore it here */
|
|
/* cast through void* to get rid of alignment warnings */
|
|
opts = (u32_t *)(void *)(seg->tcphdr + 1);
|
|
if (seg->flags & TF_SEG_OPTS_MSS) {
|
|
u16_t mss;
|
|
#if TCP_CALCULATE_EFF_SEND_MSS
|
|
mss = tcp_eff_send_mss_netif(TCP_MSS, netif, &pcb->remote_ip);
|
|
#else /* TCP_CALCULATE_EFF_SEND_MSS */
|
|
mss = TCP_MSS;
|
|
#endif /* TCP_CALCULATE_EFF_SEND_MSS */
|
|
*opts = TCP_BUILD_MSS_OPTION(mss);
|
|
opts += 1;
|
|
}
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
pcb->ts_lastacksent = pcb->rcv_nxt;
|
|
|
|
if (seg->flags & TF_SEG_OPTS_TS) {
|
|
tcp_build_timestamp_option(pcb, opts);
|
|
opts += 3;
|
|
}
|
|
#endif
|
|
#if LWIP_WND_SCALE
|
|
if (seg->flags & TF_SEG_OPTS_WND_SCALE) {
|
|
tcp_build_wnd_scale_option(opts);
|
|
opts += 1;
|
|
}
|
|
#endif
|
|
#if LWIP_TCP_SACK_OUT
|
|
if (seg->flags & TF_SEG_OPTS_SACK_PERM) {
|
|
/* Pad with two NOP options to make everything nicely aligned
|
|
* NOTE: When we send both timestamp and SACK_PERM options,
|
|
* we could use the first two NOPs before the timestamp to store SACK_PERM option,
|
|
* but that would complicate the code.
|
|
*/
|
|
*(opts++) = PP_HTONL(0x01010402);
|
|
}
|
|
#endif
|
|
|
|
/* Set retransmission timer running if it is not currently enabled
|
|
This must be set before checking the route. */
|
|
if (pcb->rtime < 0) {
|
|
pcb->rtime = 0;
|
|
}
|
|
|
|
if (pcb->rttest == 0) {
|
|
pcb->rttest = tcp_ticks;
|
|
pcb->rtseq = lwip_ntohl(seg->tcphdr->seqno);
|
|
|
|
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_output_segment: rtseq %"U32_F"\n", pcb->rtseq));
|
|
}
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output_segment: %"U32_F":%"U32_F"\n",
|
|
lwip_htonl(seg->tcphdr->seqno), lwip_htonl(seg->tcphdr->seqno) +
|
|
seg->len));
|
|
|
|
len = (u16_t)((u8_t *)seg->tcphdr - (u8_t *)seg->p->payload);
|
|
if (len == 0) {
|
|
/** Exclude retransmitted segments from this count. */
|
|
MIB2_STATS_INC(mib2.tcpoutsegs);
|
|
}
|
|
|
|
seg->p->len -= len;
|
|
seg->p->tot_len -= len;
|
|
|
|
seg->p->payload = seg->tcphdr;
|
|
|
|
seg->tcphdr->chksum = 0;
|
|
|
|
#ifdef LWIP_HOOK_TCP_OUT_ADD_TCPOPTS
|
|
opts = LWIP_HOOK_TCP_OUT_ADD_TCPOPTS(seg->p, seg->tcphdr, pcb, opts);
|
|
#endif
|
|
LWIP_ASSERT("options not filled", (u8_t *)opts == ((u8_t *)(seg->tcphdr + 1)) + LWIP_TCP_OPT_LENGTH_SEGMENT(seg->flags, pcb));
|
|
|
|
#if CHECKSUM_GEN_TCP
|
|
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_TCP) {
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
u32_t acc;
|
|
#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
|
u16_t chksum_slow = ip_chksum_pseudo(seg->p, IP_PROTO_TCP,
|
|
seg->p->tot_len, &pcb->local_ip, &pcb->remote_ip);
|
|
#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
|
if ((seg->flags & TF_SEG_DATA_CHECKSUMMED) == 0) {
|
|
LWIP_ASSERT("data included but not checksummed",
|
|
seg->p->tot_len == TCPH_HDRLEN_BYTES(seg->tcphdr));
|
|
}
|
|
|
|
/* rebuild TCP header checksum (TCP header changes for retransmissions!) */
|
|
acc = ip_chksum_pseudo_partial(seg->p, IP_PROTO_TCP,
|
|
seg->p->tot_len, TCPH_HDRLEN_BYTES(seg->tcphdr), &pcb->local_ip, &pcb->remote_ip);
|
|
/* add payload checksum */
|
|
if (seg->chksum_swapped) {
|
|
seg_chksum_was_swapped = 1;
|
|
seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
|
|
seg->chksum_swapped = 0;
|
|
}
|
|
acc = (u16_t)~acc + seg->chksum;
|
|
seg->tcphdr->chksum = (u16_t)~FOLD_U32T(acc);
|
|
#if TCP_CHECKSUM_ON_COPY_SANITY_CHECK
|
|
if (chksum_slow != seg->tcphdr->chksum) {
|
|
TCP_CHECKSUM_ON_COPY_SANITY_CHECK_FAIL(
|
|
("tcp_output_segment: calculated checksum is %"X16_F" instead of %"X16_F"\n",
|
|
seg->tcphdr->chksum, chksum_slow));
|
|
seg->tcphdr->chksum = chksum_slow;
|
|
}
|
|
#endif /* TCP_CHECKSUM_ON_COPY_SANITY_CHECK */
|
|
#else /* TCP_CHECKSUM_ON_COPY */
|
|
seg->tcphdr->chksum = ip_chksum_pseudo(seg->p, IP_PROTO_TCP,
|
|
seg->p->tot_len, &pcb->local_ip, &pcb->remote_ip);
|
|
#endif /* TCP_CHECKSUM_ON_COPY */
|
|
}
|
|
#endif /* CHECKSUM_GEN_TCP */
|
|
TCP_STATS_INC(tcp.xmit);
|
|
|
|
NETIF_SET_HINTS(netif, &(pcb->netif_hints));
|
|
err = ip_output_if(seg->p, &pcb->local_ip, &pcb->remote_ip, pcb->ttl,
|
|
pcb->tos, IP_PROTO_TCP, netif);
|
|
NETIF_RESET_HINTS(netif);
|
|
|
|
#if TCP_CHECKSUM_ON_COPY
|
|
if (seg_chksum_was_swapped) {
|
|
/* if data is added to this segment later, chksum needs to be swapped,
|
|
so restore this now */
|
|
seg->chksum = SWAP_BYTES_IN_WORD(seg->chksum);
|
|
seg->chksum_swapped = 1;
|
|
}
|
|
#endif
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* Requeue all unacked segments for retransmission
|
|
*
|
|
* Called by tcp_slowtmr() for slow retransmission.
|
|
*
|
|
* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
|
*/
|
|
err_t
|
|
tcp_rexmit_rto_prepare(struct tcp_pcb *pcb)
|
|
{
|
|
struct tcp_seg *seg;
|
|
|
|
LWIP_ASSERT("tcp_rexmit_rto_prepare: invalid pcb", pcb != NULL);
|
|
|
|
if (pcb->unacked == NULL) {
|
|
return ERR_VAL;
|
|
}
|
|
|
|
/* Move all unacked segments to the head of the unsent queue.
|
|
However, give up if any of the unsent pbufs are still referenced by the
|
|
netif driver due to deferred transmission. No point loading the link further
|
|
if it is struggling to flush its buffered writes. */
|
|
for (seg = pcb->unacked; seg->next != NULL; seg = seg->next) {
|
|
if (tcp_output_segment_busy(seg)) {
|
|
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit_rto: segment busy\n"));
|
|
return ERR_VAL;
|
|
}
|
|
}
|
|
if (tcp_output_segment_busy(seg)) {
|
|
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit_rto: segment busy\n"));
|
|
return ERR_VAL;
|
|
}
|
|
/* concatenate unsent queue after unacked queue */
|
|
seg->next = pcb->unsent;
|
|
#if TCP_OVERSIZE_DBGCHECK
|
|
/* if last unsent changed, we need to update unsent_oversize */
|
|
if (pcb->unsent == NULL) {
|
|
pcb->unsent_oversize = seg->oversize_left;
|
|
}
|
|
#endif /* TCP_OVERSIZE_DBGCHECK */
|
|
/* unsent queue is the concatenated queue (of unacked, unsent) */
|
|
pcb->unsent = pcb->unacked;
|
|
/* unacked queue is now empty */
|
|
pcb->unacked = NULL;
|
|
|
|
/* Mark RTO in-progress */
|
|
tcp_set_flags(pcb, TF_RTO);
|
|
/* Record the next byte following retransmit */
|
|
pcb->rto_end = lwip_ntohl(seg->tcphdr->seqno) + TCP_TCPLEN(seg);
|
|
/* Don't take any RTT measurements after retransmitting. */
|
|
pcb->rttest = 0;
|
|
|
|
return ERR_OK;
|
|
}
|
|
|
|
/**
|
|
* Requeue all unacked segments for retransmission
|
|
*
|
|
* Called by tcp_slowtmr() for slow retransmission.
|
|
*
|
|
* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
|
*/
|
|
void
|
|
tcp_rexmit_rto_commit(struct tcp_pcb *pcb)
|
|
{
|
|
LWIP_ASSERT("tcp_rexmit_rto_commit: invalid pcb", pcb != NULL);
|
|
|
|
/* increment number of retransmissions */
|
|
if (pcb->nrtx < 0xFF) {
|
|
++pcb->nrtx;
|
|
}
|
|
/* Do the actual retransmission */
|
|
tcp_output(pcb);
|
|
}
|
|
|
|
/**
|
|
* Requeue all unacked segments for retransmission
|
|
*
|
|
* Called by tcp_process() only, tcp_slowtmr() needs to do some things between
|
|
* "prepare" and "commit".
|
|
*
|
|
* @param pcb the tcp_pcb for which to re-enqueue all unacked segments
|
|
*/
|
|
void
|
|
tcp_rexmit_rto(struct tcp_pcb *pcb)
|
|
{
|
|
LWIP_ASSERT("tcp_rexmit_rto: invalid pcb", pcb != NULL);
|
|
|
|
if (tcp_rexmit_rto_prepare(pcb) == ERR_OK) {
|
|
tcp_rexmit_rto_commit(pcb);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Requeue the first unacked segment for retransmission
|
|
*
|
|
* Called by tcp_receive() for fast retransmit.
|
|
*
|
|
* @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
|
*/
|
|
err_t
|
|
tcp_rexmit(struct tcp_pcb *pcb)
|
|
{
|
|
struct tcp_seg *seg;
|
|
struct tcp_seg **cur_seg;
|
|
|
|
LWIP_ASSERT("tcp_rexmit: invalid pcb", pcb != NULL);
|
|
|
|
if (pcb->unacked == NULL) {
|
|
return ERR_VAL;
|
|
}
|
|
|
|
seg = pcb->unacked;
|
|
|
|
/* Give up if the segment is still referenced by the netif driver
|
|
due to deferred transmission. */
|
|
if (tcp_output_segment_busy(seg)) {
|
|
LWIP_DEBUGF(TCP_RTO_DEBUG, ("tcp_rexmit busy\n"));
|
|
return ERR_VAL;
|
|
}
|
|
|
|
/* Move the first unacked segment to the unsent queue */
|
|
/* Keep the unsent queue sorted. */
|
|
pcb->unacked = seg->next;
|
|
|
|
cur_seg = &(pcb->unsent);
|
|
while (*cur_seg &&
|
|
TCP_SEQ_LT(lwip_ntohl((*cur_seg)->tcphdr->seqno), lwip_ntohl(seg->tcphdr->seqno))) {
|
|
cur_seg = &((*cur_seg)->next );
|
|
}
|
|
seg->next = *cur_seg;
|
|
*cur_seg = seg;
|
|
#if TCP_OVERSIZE
|
|
if (seg->next == NULL) {
|
|
/* the retransmitted segment is last in unsent, so reset unsent_oversize */
|
|
pcb->unsent_oversize = 0;
|
|
}
|
|
#endif /* TCP_OVERSIZE */
|
|
|
|
if (pcb->nrtx < 0xFF) {
|
|
++pcb->nrtx;
|
|
}
|
|
|
|
/* Don't take any rtt measurements after retransmitting. */
|
|
pcb->rttest = 0;
|
|
|
|
/* Do the actual retransmission. */
|
|
MIB2_STATS_INC(mib2.tcpretranssegs);
|
|
/* No need to call tcp_output: we are always called from tcp_input()
|
|
and thus tcp_output directly returns. */
|
|
return ERR_OK;
|
|
}
|
|
|
|
|
|
/**
|
|
* Handle retransmission after three dupacks received
|
|
*
|
|
* @param pcb the tcp_pcb for which to retransmit the first unacked segment
|
|
*/
|
|
void
|
|
tcp_rexmit_fast(struct tcp_pcb *pcb)
|
|
{
|
|
LWIP_ASSERT("tcp_rexmit_fast: invalid pcb", pcb != NULL);
|
|
|
|
if (pcb->unacked != NULL && !(pcb->flags & TF_INFR)) {
|
|
/* This is fast retransmit. Retransmit the first unacked segment. */
|
|
LWIP_DEBUGF(TCP_FR_DEBUG,
|
|
("tcp_receive: dupacks %"U16_F" (%"U32_F
|
|
"), fast retransmit %"U32_F"\n",
|
|
(u16_t)pcb->dupacks, pcb->lastack,
|
|
lwip_ntohl(pcb->unacked->tcphdr->seqno)));
|
|
if (tcp_rexmit(pcb) == ERR_OK) {
|
|
/* Set ssthresh to half of the minimum of the current
|
|
* cwnd and the advertised window */
|
|
pcb->ssthresh = LWIP_MIN(pcb->cwnd, pcb->snd_wnd) / 2;
|
|
|
|
/* The minimum value for ssthresh should be 2 MSS */
|
|
if (pcb->ssthresh < (2U * pcb->mss)) {
|
|
LWIP_DEBUGF(TCP_FR_DEBUG,
|
|
("tcp_receive: The minimum value for ssthresh %"TCPWNDSIZE_F
|
|
" should be min 2 mss %"U16_F"...\n",
|
|
pcb->ssthresh, (u16_t)(2 * pcb->mss)));
|
|
pcb->ssthresh = 2 * pcb->mss;
|
|
}
|
|
|
|
pcb->cwnd = pcb->ssthresh + 3 * pcb->mss;
|
|
tcp_set_flags(pcb, TF_INFR);
|
|
|
|
/* Reset the retransmission timer to prevent immediate rto retransmissions */
|
|
pcb->rtime = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static struct pbuf *
|
|
tcp_output_alloc_header_common(u32_t ackno, u16_t optlen, u16_t datalen,
|
|
u32_t seqno_be /* already in network byte order */,
|
|
u16_t src_port, u16_t dst_port, u8_t flags, u16_t wnd)
|
|
{
|
|
struct tcp_hdr *tcphdr;
|
|
struct pbuf *p;
|
|
|
|
p = pbuf_alloc(PBUF_IP, TCP_HLEN + optlen + datalen, PBUF_RAM);
|
|
if (p != NULL) {
|
|
LWIP_ASSERT("check that first pbuf can hold struct tcp_hdr",
|
|
(p->len >= TCP_HLEN + optlen));
|
|
tcphdr = (struct tcp_hdr *)p->payload;
|
|
tcphdr->src = lwip_htons(src_port);
|
|
tcphdr->dest = lwip_htons(dst_port);
|
|
tcphdr->seqno = seqno_be;
|
|
tcphdr->ackno = lwip_htonl(ackno);
|
|
TCPH_HDRLEN_FLAGS_SET(tcphdr, (5 + optlen / 4), flags);
|
|
tcphdr->wnd = lwip_htons(wnd);
|
|
tcphdr->chksum = 0;
|
|
tcphdr->urgp = 0;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
/** Allocate a pbuf and create a tcphdr at p->payload, used for output
|
|
* functions other than the default tcp_output -> tcp_output_segment
|
|
* (e.g. tcp_send_empty_ack, etc.)
|
|
*
|
|
* @param pcb tcp pcb for which to send a packet (used to initialize tcp_hdr)
|
|
* @param optlen length of header-options
|
|
* @param datalen length of tcp data to reserve in pbuf
|
|
* @param seqno_be seqno in network byte order (big-endian)
|
|
* @return pbuf with p->payload being the tcp_hdr
|
|
*/
|
|
static struct pbuf *
|
|
tcp_output_alloc_header(struct tcp_pcb *pcb, u16_t optlen, u16_t datalen,
|
|
u32_t seqno_be /* already in network byte order */)
|
|
{
|
|
struct pbuf *p;
|
|
|
|
LWIP_ASSERT("tcp_output_alloc_header: invalid pcb", pcb != NULL);
|
|
|
|
p = tcp_output_alloc_header_common(pcb->rcv_nxt, optlen, datalen,
|
|
seqno_be, pcb->local_port, pcb->remote_port, TCP_ACK,
|
|
TCPWND_MIN16(RCV_WND_SCALE(pcb, pcb->rcv_ann_wnd)));
|
|
if (p != NULL) {
|
|
/* If we're sending a packet, update the announced right window edge */
|
|
pcb->rcv_ann_right_edge = pcb->rcv_nxt + pcb->rcv_ann_wnd;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
/* Fill in options for control segments */
|
|
static void
|
|
tcp_output_fill_options(const struct tcp_pcb *pcb, struct pbuf *p, u8_t optflags, u8_t num_sacks)
|
|
{
|
|
struct tcp_hdr *tcphdr;
|
|
u32_t *opts;
|
|
u16_t sacks_len = 0;
|
|
|
|
LWIP_ASSERT("tcp_output_fill_options: invalid pbuf", p != NULL);
|
|
|
|
tcphdr = (struct tcp_hdr *)p->payload;
|
|
opts = (u32_t *)(void *)(tcphdr + 1);
|
|
|
|
/* NB. MSS and window scale options are only sent on SYNs, so ignore them here */
|
|
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
if (optflags & TF_SEG_OPTS_TS) {
|
|
tcp_build_timestamp_option(pcb, opts);
|
|
opts += 3;
|
|
}
|
|
#endif
|
|
|
|
#if LWIP_TCP_SACK_OUT
|
|
if (pcb && (num_sacks > 0)) {
|
|
tcp_build_sack_option(pcb, opts, num_sacks);
|
|
/* 1 word for SACKs header (including 2xNOP), and 2 words for each SACK */
|
|
sacks_len = 1 + num_sacks * 2;
|
|
opts += sacks_len;
|
|
}
|
|
#else
|
|
LWIP_UNUSED_ARG(num_sacks);
|
|
#endif
|
|
|
|
#ifdef LWIP_HOOK_TCP_OUT_ADD_TCPOPTS
|
|
opts = LWIP_HOOK_TCP_OUT_ADD_TCPOPTS(p, tcphdr, pcb, opts);
|
|
#endif
|
|
|
|
LWIP_UNUSED_ARG(pcb);
|
|
LWIP_UNUSED_ARG(sacks_len);
|
|
LWIP_ASSERT("options not filled", (u8_t *)opts == ((u8_t *)(tcphdr + 1)) + sacks_len * 4 + LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb));
|
|
LWIP_UNUSED_ARG(optflags); /* for LWIP_NOASSERT */
|
|
LWIP_UNUSED_ARG(opts); /* for LWIP_NOASSERT */
|
|
}
|
|
|
|
/** Output a control segment pbuf to IP.
|
|
*
|
|
* Called from tcp_rst, tcp_send_empty_ack, tcp_keepalive and tcp_zero_window_probe,
|
|
* this function combines selecting a netif for transmission, generating the tcp
|
|
* header checksum and calling ip_output_if while handling netif hints and stats.
|
|
*/
|
|
static err_t
|
|
tcp_output_control_segment(const struct tcp_pcb *pcb, struct pbuf *p,
|
|
const ip_addr_t *src, const ip_addr_t *dst)
|
|
{
|
|
err_t err;
|
|
struct netif *netif;
|
|
|
|
LWIP_ASSERT("tcp_output_control_segment: invalid pbuf", p != NULL);
|
|
|
|
netif = tcp_route(pcb, src, dst);
|
|
if (netif == NULL) {
|
|
err = ERR_RTE;
|
|
} else {
|
|
u8_t ttl, tos;
|
|
#if CHECKSUM_GEN_TCP
|
|
IF__NETIF_CHECKSUM_ENABLED(netif, NETIF_CHECKSUM_GEN_TCP) {
|
|
struct tcp_hdr *tcphdr = (struct tcp_hdr *)p->payload;
|
|
tcphdr->chksum = ip_chksum_pseudo(p, IP_PROTO_TCP, p->tot_len,
|
|
src, dst);
|
|
}
|
|
#endif
|
|
if (pcb != NULL) {
|
|
NETIF_SET_HINTS(netif, LWIP_CONST_CAST(struct netif_hint*, &(pcb->netif_hints)));
|
|
ttl = pcb->ttl;
|
|
tos = pcb->tos;
|
|
} else {
|
|
/* Send output with hardcoded TTL/HL since we have no access to the pcb */
|
|
ttl = TCP_TTL;
|
|
tos = 0;
|
|
}
|
|
TCP_STATS_INC(tcp.xmit);
|
|
err = ip_output_if(p, src, dst, ttl, tos, IP_PROTO_TCP, netif);
|
|
NETIF_RESET_HINTS(netif);
|
|
}
|
|
pbuf_free(p);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* Send a TCP RESET packet (empty segment with RST flag set) either to
|
|
* abort a connection or to show that there is no matching local connection
|
|
* for a received segment.
|
|
*
|
|
* Called by tcp_abort() (to abort a local connection), tcp_input() (if no
|
|
* matching local pcb was found), tcp_listen_input() (if incoming segment
|
|
* has ACK flag set) and tcp_process() (received segment in the wrong state)
|
|
*
|
|
* Since a RST segment is in most cases not sent for an active connection,
|
|
* tcp_rst() has a number of arguments that are taken from a tcp_pcb for
|
|
* most other segment output functions.
|
|
*
|
|
* @param pcb TCP pcb (may be NULL if no pcb is available)
|
|
* @param seqno the sequence number to use for the outgoing segment
|
|
* @param ackno the acknowledge number to use for the outgoing segment
|
|
* @param local_ip the local IP address to send the segment from
|
|
* @param remote_ip the remote IP address to send the segment to
|
|
* @param local_port the local TCP port to send the segment from
|
|
* @param remote_port the remote TCP port to send the segment to
|
|
*/
|
|
void
|
|
tcp_rst(const struct tcp_pcb *pcb, u32_t seqno, u32_t ackno,
|
|
const ip_addr_t *local_ip, const ip_addr_t *remote_ip,
|
|
u16_t local_port, u16_t remote_port)
|
|
{
|
|
struct pbuf *p;
|
|
u16_t wnd;
|
|
u8_t optlen;
|
|
|
|
LWIP_ASSERT("tcp_rst: invalid local_ip", local_ip != NULL);
|
|
LWIP_ASSERT("tcp_rst: invalid remote_ip", remote_ip != NULL);
|
|
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
|
|
|
#if LWIP_WND_SCALE
|
|
wnd = PP_HTONS(((TCP_WND >> TCP_RCV_SCALE) & 0xFFFF));
|
|
#else
|
|
wnd = PP_HTONS(TCP_WND);
|
|
#endif
|
|
|
|
p = tcp_output_alloc_header_common(ackno, optlen, 0, lwip_htonl(seqno), local_port,
|
|
remote_port, TCP_RST | TCP_ACK, wnd);
|
|
if (p == NULL) {
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_rst: could not allocate memory for pbuf\n"));
|
|
return;
|
|
}
|
|
tcp_output_fill_options(pcb, p, 0, optlen);
|
|
|
|
MIB2_STATS_INC(mib2.tcpoutrsts);
|
|
|
|
tcp_output_control_segment(pcb, p, local_ip, remote_ip);
|
|
LWIP_DEBUGF(TCP_RST_DEBUG, ("tcp_rst: seqno %"U32_F" ackno %"U32_F".\n", seqno, ackno));
|
|
}
|
|
|
|
/**
|
|
* Send an ACK without data.
|
|
*
|
|
* @param pcb Protocol control block for the TCP connection to send the ACK
|
|
*/
|
|
err_t
|
|
tcp_send_empty_ack(struct tcp_pcb *pcb)
|
|
{
|
|
err_t err;
|
|
struct pbuf *p;
|
|
u8_t optlen, optflags = 0;
|
|
u8_t num_sacks = 0;
|
|
|
|
LWIP_ASSERT("tcp_send_empty_ack: invalid pcb", pcb != NULL);
|
|
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
if (pcb->flags & TF_TIMESTAMP) {
|
|
optflags = TF_SEG_OPTS_TS;
|
|
}
|
|
#endif
|
|
optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(optflags, pcb);
|
|
|
|
#if LWIP_TCP_SACK_OUT
|
|
/* For now, SACKs are only sent with empty ACKs */
|
|
if ((num_sacks = tcp_get_num_sacks(pcb, optlen)) > 0) {
|
|
optlen += 4 + num_sacks * 8; /* 4 bytes for header (including 2*NOP), plus 8B for each SACK */
|
|
}
|
|
#endif
|
|
|
|
p = tcp_output_alloc_header(pcb, optlen, 0, lwip_htonl(pcb->snd_nxt));
|
|
if (p == NULL) {
|
|
/* let tcp_fasttmr retry sending this ACK */
|
|
tcp_set_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG, ("tcp_output: (ACK) could not allocate pbuf\n"));
|
|
return ERR_BUF;
|
|
}
|
|
tcp_output_fill_options(pcb, p, optflags, num_sacks);
|
|
|
|
#if LWIP_TCP_TIMESTAMPS
|
|
pcb->ts_lastacksent = pcb->rcv_nxt;
|
|
#endif
|
|
|
|
LWIP_DEBUGF(TCP_OUTPUT_DEBUG,
|
|
("tcp_output: sending ACK for %"U32_F"\n", pcb->rcv_nxt));
|
|
err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
|
if (err != ERR_OK) {
|
|
/* let tcp_fasttmr retry sending this ACK */
|
|
tcp_set_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
|
} else {
|
|
/* remove ACK flags from the PCB, as we sent an empty ACK now */
|
|
tcp_clear_flags(pcb, TF_ACK_DELAY | TF_ACK_NOW);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* Send keepalive packets to keep a connection active although
|
|
* no data is sent over it.
|
|
*
|
|
* Called by tcp_slowtmr()
|
|
*
|
|
* @param pcb the tcp_pcb for which to send a keepalive packet
|
|
*/
|
|
err_t
|
|
tcp_keepalive(struct tcp_pcb *pcb)
|
|
{
|
|
err_t err;
|
|
struct pbuf *p;
|
|
u8_t optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
|
|
|
LWIP_ASSERT("tcp_keepalive: invalid pcb", pcb != NULL);
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to "));
|
|
ip_addr_debug_print_val(TCP_DEBUG, pcb->remote_ip);
|
|
LWIP_DEBUGF(TCP_DEBUG, ("\n"));
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: tcp_ticks %"U32_F" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
|
tcp_ticks, pcb->tmr, (u16_t)pcb->keep_cnt_sent));
|
|
|
|
p = tcp_output_alloc_header(pcb, optlen, 0, lwip_htonl(pcb->snd_nxt - 1));
|
|
if (p == NULL) {
|
|
LWIP_DEBUGF(TCP_DEBUG,
|
|
("tcp_keepalive: could not allocate memory for pbuf\n"));
|
|
return ERR_MEM;
|
|
}
|
|
tcp_output_fill_options(pcb, p, 0, optlen);
|
|
err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: seqno %"U32_F" ackno %"U32_F" err %d.\n",
|
|
pcb->snd_nxt - 1, pcb->rcv_nxt, (int)err));
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* Send persist timer zero-window probes to keep a connection active
|
|
* when a window update is lost.
|
|
*
|
|
* Called by tcp_slowtmr()
|
|
*
|
|
* @param pcb the tcp_pcb for which to send a zero-window probe packet
|
|
*/
|
|
err_t
|
|
tcp_zero_window_probe(struct tcp_pcb *pcb)
|
|
{
|
|
err_t err;
|
|
struct pbuf *p;
|
|
struct tcp_hdr *tcphdr;
|
|
struct tcp_seg *seg;
|
|
u16_t len;
|
|
u8_t is_fin;
|
|
u32_t snd_nxt;
|
|
u8_t optlen = LWIP_TCP_OPT_LENGTH_SEGMENT(0, pcb);
|
|
|
|
LWIP_ASSERT("tcp_zero_window_probe: invalid pcb", pcb != NULL);
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: sending ZERO WINDOW probe to "));
|
|
ip_addr_debug_print_val(TCP_DEBUG, pcb->remote_ip);
|
|
LWIP_DEBUGF(TCP_DEBUG, ("\n"));
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG,
|
|
("tcp_zero_window_probe: tcp_ticks %"U32_F
|
|
" pcb->tmr %"U32_F" pcb->keep_cnt_sent %"U16_F"\n",
|
|
tcp_ticks, pcb->tmr, (u16_t)pcb->keep_cnt_sent));
|
|
|
|
/* Only consider unsent, persist timer should be off when there is data in-flight */
|
|
seg = pcb->unsent;
|
|
if (seg == NULL) {
|
|
/* Not expected, persist timer should be off when the send buffer is empty */
|
|
return ERR_OK;
|
|
}
|
|
|
|
/* increment probe count. NOTE: we record probe even if it fails
|
|
to actually transmit due to an error. This ensures memory exhaustion/
|
|
routing problem doesn't leave a zero-window pcb as an indefinite zombie.
|
|
RTO mechanism has similar behavior, see pcb->nrtx */
|
|
if (pcb->persist_probe < 0xFF) {
|
|
++pcb->persist_probe;
|
|
}
|
|
|
|
is_fin = ((TCPH_FLAGS(seg->tcphdr) & TCP_FIN) != 0) && (seg->len == 0);
|
|
/* we want to send one seqno: either FIN or data (no options) */
|
|
len = is_fin ? 0 : 1;
|
|
|
|
p = tcp_output_alloc_header(pcb, optlen, len, seg->tcphdr->seqno);
|
|
if (p == NULL) {
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: no memory for pbuf\n"));
|
|
return ERR_MEM;
|
|
}
|
|
tcphdr = (struct tcp_hdr *)p->payload;
|
|
|
|
if (is_fin) {
|
|
/* FIN segment, no data */
|
|
TCPH_FLAGS_SET(tcphdr, TCP_ACK | TCP_FIN);
|
|
} else {
|
|
/* Data segment, copy in one byte from the head of the unacked queue */
|
|
char *d = ((char *)p->payload + TCP_HLEN);
|
|
/* Depending on whether the segment has already been sent (unacked) or not
|
|
(unsent), seg->p->payload points to the IP header or TCP header.
|
|
Ensure we copy the first TCP data byte: */
|
|
pbuf_copy_partial(seg->p, d, 1, seg->p->tot_len - seg->len);
|
|
}
|
|
|
|
/* The byte may be acknowledged without the window being opened. */
|
|
snd_nxt = lwip_ntohl(seg->tcphdr->seqno) + 1;
|
|
if (TCP_SEQ_LT(pcb->snd_nxt, snd_nxt)) {
|
|
pcb->snd_nxt = snd_nxt;
|
|
}
|
|
tcp_output_fill_options(pcb, p, 0, optlen);
|
|
|
|
err = tcp_output_control_segment(pcb, p, &pcb->local_ip, &pcb->remote_ip);
|
|
|
|
LWIP_DEBUGF(TCP_DEBUG, ("tcp_zero_window_probe: seqno %"U32_F
|
|
" ackno %"U32_F" err %d.\n",
|
|
pcb->snd_nxt - 1, pcb->rcv_nxt, (int)err));
|
|
return err;
|
|
}
|
|
#endif /* LWIP_TCP */
|