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tcp.c
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/** @file
* @brief TCP handler
*
* Handle TCP connections.
*/
/*
* Copyright (c) 2016 Intel Corporation
* Copyright 2011-2015 by Andrey Butok. FNET Community.
* Copyright 2008-2010 by Andrey Butok. Freescale Semiconductor, Inc.
* Copyright 2003 by Alexey Shervashidze, Andrey Butok. Motorola SPS.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <logging/log.h>
LOG_MODULE_REGISTER(net_tcp, CONFIG_NET_TCP_LOG_LEVEL);
#include <kernel.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
#include <net/net_pkt.h>
#include <net/net_ip.h>
#include <net/net_context.h>
#include <sys/byteorder.h>
#include "connection.h"
#include "net_private.h"
#include "ipv6.h"
#include "ipv4.h"
#include "tcp_internal.h"
#include "net_stats.h"
#define ALLOC_TIMEOUT K_MSEC(500)
static int net_tcp_queue_pkt(struct net_context *context, struct net_pkt *pkt);
/*
* Each TCP connection needs to be tracked by net_context, so
* we need to allocate equal number of control structures here.
*/
#define NET_MAX_TCP_CONTEXT CONFIG_NET_MAX_CONTEXTS
static struct net_tcp tcp_context[NET_MAX_TCP_CONTEXT];
static struct tcp_backlog_entry {
struct net_tcp *tcp;
u32_t send_seq;
u32_t send_ack;
struct k_delayed_work ack_timer;
struct sockaddr remote;
u16_t send_mss;
} tcp_backlog[CONFIG_NET_TCP_BACKLOG_SIZE];
#if defined(CONFIG_NET_TCP_ACK_TIMEOUT)
#define ACK_TIMEOUT CONFIG_NET_TCP_ACK_TIMEOUT
#else
#define ACK_TIMEOUT K_SECONDS(1)
#endif
#define FIN_TIMEOUT K_SECONDS(1)
/* Declares a wrapper function for a net_conn callback that refs the
* context around the invocation (to protect it from premature
* deletion). Long term would be nice to see this feature be part of
* the connection type itself, but right now it has opaque "user_data"
* pointers and doesn't understand what a net_context is.
*/
#define NET_CONN_CB(name) \
static enum net_verdict _##name(struct net_conn *conn, \
struct net_pkt *pkt, \
union net_ip_header *ip_hdr, \
union net_proto_header *proto_hdr, \
void *user_data); \
static enum net_verdict name(struct net_conn *conn, \
struct net_pkt *pkt, \
union net_ip_header *ip_hdr, \
union net_proto_header *proto_hdr, \
void *user_data) \
{ \
enum net_verdict result; \
\
net_context_ref(user_data); \
result = _##name(conn, pkt, ip_hdr, \
proto_hdr, user_data); \
net_context_unref(user_data); \
return result; \
} \
static enum net_verdict _##name(struct net_conn *conn, \
struct net_pkt *pkt, \
union net_ip_header *ip_hdr, \
union net_proto_header *proto_hdr, \
void *user_data) \
struct tcp_segment {
u32_t seq;
u32_t ack;
u16_t wnd;
u8_t flags;
u8_t optlen;
void *options;
struct sockaddr_ptr *src_addr;
const struct sockaddr *dst_addr;
};
static char upper_if_set(char chr, bool set)
{
if (set) {
return chr & ~0x20;
}
return chr | 0x20;
}
static void net_tcp_trace(struct net_pkt *pkt,
struct net_tcp *tcp,
struct net_tcp_hdr *tcp_hdr)
{
u32_t rel_ack, ack;
u8_t flags;
if (CONFIG_NET_TCP_LOG_LEVEL < LOG_LEVEL_DBG) {
return;
}
flags = NET_TCP_FLAGS(tcp_hdr);
ack = sys_get_be32(tcp_hdr->ack);
if (!tcp->sent_ack) {
rel_ack = 0U;
} else {
rel_ack = ack ? ack - tcp->sent_ack : 0;
}
NET_DBG("[%p] pkt %p src %u dst %u",
tcp, pkt,
ntohs(tcp_hdr->src_port),
ntohs(tcp_hdr->dst_port));
NET_DBG(" seq 0x%04x (%u) ack 0x%04x (%u/%u)",
sys_get_be32(tcp_hdr->seq),
sys_get_be32(tcp_hdr->seq),
ack,
ack,
/* This tells how many bytes we are acking now */
rel_ack);
NET_DBG(" flags %c%c%c%c%c%c",
upper_if_set('u', flags & NET_TCP_URG),
upper_if_set('a', flags & NET_TCP_ACK),
upper_if_set('p', flags & NET_TCP_PSH),
upper_if_set('r', flags & NET_TCP_RST),
upper_if_set('s', flags & NET_TCP_SYN),
upper_if_set('f', flags & NET_TCP_FIN));
NET_DBG(" win %u chk 0x%04x",
sys_get_be16(tcp_hdr->wnd),
ntohs(tcp_hdr->chksum));
}
static inline u32_t retry_timeout(const struct net_tcp *tcp)
{
return ((u32_t)1 << tcp->retry_timeout_shift) *
CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT;
}
#define is_6lo_technology(pkt) \
(IS_ENABLED(CONFIG_NET_IPV6) && net_pkt_family(pkt) == AF_INET6 && \
((IS_ENABLED(CONFIG_NET_L2_BT) && \
net_pkt_lladdr_dst(pkt)->type == NET_LINK_BLUETOOTH) || \
(IS_ENABLED(CONFIG_NET_L2_IEEE802154) && \
net_pkt_lladdr_dst(pkt)->type == NET_LINK_IEEE802154) || \
(IS_ENABLED(CONFIG_NET_L2_CANBUS) && \
net_pkt_lladdr_dst(pkt)->type == NET_LINK_CANBUS)))
/* The ref should not be done for Bluetooth and IEEE 802.15.4 which use
* IPv6 header compression (6lo). For BT and 802.15.4 we copy the pkt
* chain we are about to send so it is fine if the network driver
* releases it. As we have our own copy of the sent data, we do not
* need to take a reference of it. See also net_tcp_send_pkt().
*
* Note that this is macro so that we get information who called the
* net_pkt_ref() if memory debugging is active.
*/
#define do_ref_if_needed(tcp, pkt) \
do { \
if (!is_6lo_technology(pkt)) { \
NET_DBG("[%p] ref pkt %p new ref %d (%s:%d)", \
tcp, pkt, atomic_get(&pkt->atomic_ref) + 1, \
__func__, __LINE__); \
pkt = net_pkt_ref(pkt); \
} \
} while (0)
static void abort_connection(struct net_tcp *tcp)
{
struct net_context *ctx = tcp->context;
NET_DBG("[%p] segment retransmission exceeds %d, resetting context %p",
tcp, CONFIG_NET_TCP_RETRY_COUNT, ctx);
if (ctx->recv_cb) {
ctx->recv_cb(ctx, NULL, NULL, NULL, -ECONNRESET,
tcp->recv_user_data);
}
net_context_unref(ctx);
}
static void tcp_retry_expired(struct k_work *work)
{
struct net_tcp *tcp = CONTAINER_OF(work, struct net_tcp, retry_timer);
struct net_pkt *pkt;
/* Double the retry period for exponential backoff and resend
* the first (only the first!) unack'd packet.
*/
if (!sys_slist_is_empty(&tcp->sent_list)) {
tcp->retry_timeout_shift++;
if (tcp->retry_timeout_shift > CONFIG_NET_TCP_RETRY_COUNT) {
abort_connection(tcp);
return;
}
k_delayed_work_submit(&tcp->retry_timer, retry_timeout(tcp));
pkt = CONTAINER_OF(sys_slist_peek_head(&tcp->sent_list),
struct net_pkt, sent_list);
if (net_pkt_sent(pkt)) {
do_ref_if_needed(tcp, pkt);
net_pkt_set_sent(pkt, false);
}
net_pkt_set_queued(pkt, true);
if (net_tcp_send_pkt(pkt) < 0 && !is_6lo_technology(pkt)) {
NET_DBG("retry %u: [%p] pkt %p send failed",
tcp->retry_timeout_shift, tcp, pkt);
net_pkt_unref(pkt);
} else {
NET_DBG("retry %u: [%p] sent pkt %p",
tcp->retry_timeout_shift, tcp, pkt);
if (IS_ENABLED(CONFIG_NET_STATISTICS_TCP) &&
!is_6lo_technology(pkt)) {
net_stats_update_tcp_seg_rexmit(
net_pkt_iface(pkt));
}
}
} else if (CONFIG_NET_TCP_TIME_WAIT_DELAY != 0) {
if (tcp->fin_sent && tcp->fin_rcvd) {
NET_DBG("[%p] Closing connection (context %p)",
tcp, tcp->context);
net_context_unref(tcp->context);
}
}
}
struct net_tcp *net_tcp_alloc(struct net_context *context)
{
int i, key;
key = irq_lock();
for (i = 0; i < NET_MAX_TCP_CONTEXT; i++) {
if (!net_tcp_is_used(&tcp_context[i])) {
tcp_context[i].flags |= NET_TCP_IN_USE;
break;
}
}
irq_unlock(key);
if (i >= NET_MAX_TCP_CONTEXT) {
return NULL;
}
(void)memset(&tcp_context[i], 0, sizeof(struct net_tcp));
tcp_context[i].flags = NET_TCP_IN_USE;
tcp_context[i].state = NET_TCP_CLOSED;
tcp_context[i].context = context;
tcp_context[i].send_seq = tcp_init_isn();
tcp_context[i].recv_wnd = MIN(NET_TCP_MAX_WIN, NET_TCP_BUF_MAX_LEN);
tcp_context[i].send_mss = NET_TCP_DEFAULT_MSS;
tcp_context[i].accept_cb = NULL;
k_delayed_work_init(&tcp_context[i].retry_timer, tcp_retry_expired);
k_sem_init(&tcp_context[i].connect_wait, 0, UINT_MAX);
return &tcp_context[i];
}
static void ack_timer_cancel(struct net_tcp *tcp)
{
k_delayed_work_cancel(&tcp->ack_timer);
}
static void fin_timer_cancel(struct net_tcp *tcp)
{
k_delayed_work_cancel(&tcp->fin_timer);
}
static void retry_timer_cancel(struct net_tcp *tcp)
{
k_delayed_work_cancel(&tcp->retry_timer);
}
static void timewait_timer_cancel(struct net_tcp *tcp)
{
k_delayed_work_cancel(&tcp->timewait_timer);
}
int net_tcp_release(struct net_tcp *tcp)
{
struct net_pkt *pkt;
struct net_pkt *tmp;
unsigned int key;
if (!PART_OF_ARRAY(tcp_context, tcp)) {
return -EINVAL;
}
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&tcp->sent_list, pkt, tmp,
sent_list) {
sys_slist_remove(&tcp->sent_list, NULL, &pkt->sent_list);
net_pkt_unref(pkt);
}
retry_timer_cancel(tcp);
k_sem_reset(&tcp->connect_wait);
ack_timer_cancel(tcp);
fin_timer_cancel(tcp);
timewait_timer_cancel(tcp);
net_tcp_change_state(tcp, NET_TCP_CLOSED);
tcp->context = NULL;
key = irq_lock();
tcp->flags &= ~(NET_TCP_IN_USE | NET_TCP_RECV_MSS_SET);
irq_unlock(key);
NET_DBG("[%p] Disposed of TCP connection state", tcp);
return 0;
}
static int finalize_segment(struct net_pkt *pkt)
{
net_pkt_cursor_init(pkt);
if (IS_ENABLED(CONFIG_NET_IPV4) &&
net_pkt_family(pkt) == AF_INET) {
return net_ipv4_finalize(pkt, IPPROTO_TCP);
} else if (IS_ENABLED(CONFIG_NET_IPV6) &&
net_pkt_family(pkt) == AF_INET6) {
return net_ipv6_finalize(pkt, IPPROTO_TCP);
}
return -EINVAL;
}
static int prepare_segment(struct net_tcp *tcp,
struct tcp_segment *segment,
struct net_pkt *pkt,
struct net_pkt **out_pkt)
{
NET_PKT_DATA_ACCESS_DEFINE(tcp_access, struct net_tcp_hdr);
struct net_context *context = tcp->context;
struct net_buf *tail = NULL;
struct net_tcp_hdr *tcp_hdr;
u16_t dst_port, src_port;
bool pkt_allocated;
u8_t optlen = 0U;
int status;
NET_ASSERT(context);
if (pkt) {
/* TCP transmit data comes in with a pre-allocated
* net_pkt at the head (so that net_context_send can find
* the context), and the data after. Rejigger so we
* can insert a TCP header cleanly
*/
tail = pkt->buffer;
pkt->buffer = NULL;
pkt_allocated = false;
status = net_pkt_alloc_buffer(pkt, segment->optlen,
IPPROTO_TCP, ALLOC_TIMEOUT);
if (status) {
goto fail;
}
} else {
pkt = net_pkt_alloc_with_buffer(net_context_get_iface(context),
segment->optlen,
net_context_get_family(context),
IPPROTO_TCP, ALLOC_TIMEOUT);
if (!pkt) {
return -ENOMEM;
}
net_pkt_set_context(pkt, context);
pkt_allocated = true;
}
if (IS_ENABLED(CONFIG_NET_IPV4) &&
net_pkt_family(pkt) == AF_INET) {
status = net_context_create_ipv4_new(context, pkt,
net_sin_ptr(segment->src_addr)->sin_addr,
&(net_sin(segment->dst_addr)->sin_addr));
if (status < 0) {
goto fail;
}
dst_port = net_sin(segment->dst_addr)->sin_port;
src_port = ((struct sockaddr_in_ptr *)&context->local)->
sin_port;
} else if (IS_ENABLED(CONFIG_NET_IPV6) &&
net_pkt_family(pkt) == AF_INET6) {
status = net_context_create_ipv6_new(context, pkt,
net_sin6_ptr(segment->src_addr)->sin6_addr,
&(net_sin6(segment->dst_addr)->sin6_addr));
if (status < 0) {
goto fail;
}
dst_port = net_sin6(segment->dst_addr)->sin6_port;
src_port = ((struct sockaddr_in6_ptr *)&context->local)->
sin6_port;
} else {
NET_DBG("[%p] Protocol family %d not supported", tcp,
net_pkt_family(pkt));
status = -EINVAL;
goto fail;
}
tcp_hdr = (struct net_tcp_hdr *)net_pkt_get_data(pkt, &tcp_access);
if (!tcp_hdr) {
status = -ENOBUFS;
goto fail;
}
if (segment->options && segment->optlen) {
/* Set the length (this value is saved in 4-byte words format)
*/
if ((segment->optlen & 0x3u) != 0u) {
optlen = (segment->optlen & 0xfffCu) + 4u;
} else {
optlen = segment->optlen;
}
}
memset(tcp_hdr, 0, NET_TCPH_LEN);
tcp_hdr->src_port = src_port;
tcp_hdr->dst_port = dst_port;
sys_put_be32(segment->seq, tcp_hdr->seq);
sys_put_be32(segment->ack, tcp_hdr->ack);
tcp_hdr->offset = (NET_TCPH_LEN + optlen) << 2;
tcp_hdr->flags = segment->flags;
sys_put_be16(segment->wnd, tcp_hdr->wnd);
tcp_hdr->chksum = 0U;
tcp_hdr->urg[0] = 0U;
tcp_hdr->urg[1] = 0U;
net_pkt_set_data(pkt, &tcp_access);
if (optlen && net_pkt_write(pkt, segment->options, segment->optlen)) {
goto fail;
}
if (tail) {
net_pkt_append_buffer(pkt, tail);
}
status = finalize_segment(pkt);
if (status < 0) {
if (pkt_allocated) {
net_pkt_unref(pkt);
}
return status;
}
net_tcp_trace(pkt, tcp, tcp_hdr);
*out_pkt = pkt;
return 0;
fail:
if (pkt_allocated) {
net_pkt_unref(pkt);
} else {
net_buf_unref(pkt->buffer);
pkt->buffer = tail;
}
return status;
}
u32_t net_tcp_get_recv_wnd(const struct net_tcp *tcp)
{
return tcp->recv_wnd;
}
int net_tcp_prepare_segment(struct net_tcp *tcp, u8_t flags,
void *options, size_t optlen,
const struct sockaddr_ptr *local,
const struct sockaddr *remote,
struct net_pkt **send_pkt)
{
struct tcp_segment segment = { 0 };
u32_t seq;
u16_t wnd;
int status;
if (!local) {
local = &tcp->context->local;
}
seq = tcp->send_seq;
if (flags & NET_TCP_ACK) {
if (net_tcp_get_state(tcp) == NET_TCP_FIN_WAIT_1) {
if (flags & NET_TCP_FIN) {
/* FIN is used here only to determine which
* state to go to next; it's not to be used
* in the sent segment.
*/
flags &= ~NET_TCP_FIN;
net_tcp_change_state(tcp, NET_TCP_TIME_WAIT);
} else {
net_tcp_change_state(tcp, NET_TCP_CLOSING);
}
} else if (net_tcp_get_state(tcp) == NET_TCP_FIN_WAIT_2) {
net_tcp_change_state(tcp, NET_TCP_TIME_WAIT);
} else if (net_tcp_get_state(tcp) == NET_TCP_CLOSE_WAIT) {
tcp->flags |= NET_TCP_IS_SHUTDOWN;
flags |= NET_TCP_FIN;
net_tcp_change_state(tcp, NET_TCP_LAST_ACK);
}
}
if (flags & NET_TCP_FIN) {
/* RFC793 says about ACK bit: "Once a connection is
* established this is always sent." as teardown
* happens when connection is established, it must
* have ACK set.
*/
flags |= NET_TCP_ACK;
seq++;
if (net_tcp_get_state(tcp) == NET_TCP_ESTABLISHED ||
net_tcp_get_state(tcp) == NET_TCP_SYN_RCVD) {
net_tcp_change_state(tcp, NET_TCP_FIN_WAIT_1);
}
}
wnd = net_tcp_get_recv_wnd(tcp);
segment.src_addr = (struct sockaddr_ptr *)local;
segment.dst_addr = remote;
segment.seq = tcp->send_seq;
segment.ack = tcp->send_ack;
segment.flags = flags;
segment.wnd = wnd;
segment.options = options;
segment.optlen = optlen;
status = prepare_segment(tcp, &segment, *send_pkt, send_pkt);
if (status < 0) {
return status;
}
tcp->send_seq = seq;
return 0;
}
static inline u32_t get_size(u32_t pos1, u32_t pos2)
{
u32_t size;
if (pos1 <= pos2) {
size = pos2 - pos1;
} else {
size = NET_TCP_MAX_SEQ - pos1 + pos2 + 1;
}
return size;
}
#if defined(CONFIG_NET_IPV4)
#ifndef NET_IP_MAX_PACKET
#define NET_IP_MAX_PACKET (10 * 1024)
#endif
#define NET_IP_MAX_OPTIONS 40 /* Maximum option field length */
static inline size_t ip_max_packet_len(struct in_addr *dest_ip)
{
ARG_UNUSED(dest_ip);
return (NET_IP_MAX_PACKET - (NET_IP_MAX_OPTIONS +
sizeof(struct net_ipv4_hdr))) & (~0x3LU);
}
#else /* CONFIG_NET_IPV4 */
#define ip_max_packet_len(...) 0
#endif /* CONFIG_NET_IPV4 */
u16_t net_tcp_get_recv_mss(const struct net_tcp *tcp)
{
sa_family_t family = net_context_get_family(tcp->context);
if (family == AF_INET) {
#if defined(CONFIG_NET_IPV4)
struct net_if *iface = net_context_get_iface(tcp->context);
if (iface && net_if_get_mtu(iface) >= NET_IPV4TCPH_LEN) {
/* Detect MSS based on interface MTU minus "TCP,IP
* header size"
*/
return net_if_get_mtu(iface) - NET_IPV4TCPH_LEN;
}
#else
return 0;
#endif /* CONFIG_NET_IPV4 */
}
#if defined(CONFIG_NET_IPV6)
else if (family == AF_INET6) {
struct net_if *iface = net_context_get_iface(tcp->context);
int mss = 0;
if (iface && net_if_get_mtu(iface) >= NET_IPV6TCPH_LEN) {
/* Detect MSS based on interface MTU minus "TCP,IP
* header size"
*/
mss = net_if_get_mtu(iface) - NET_IPV6TCPH_LEN;
}
if (mss < NET_IPV6_MTU) {
mss = NET_IPV6_MTU;
}
return mss;
}
#endif /* CONFIG_NET_IPV6 */
return 0;
}
static void net_tcp_set_syn_opt(struct net_tcp *tcp, u8_t *options,
u8_t *optionlen)
{
u32_t recv_mss;
*optionlen = 0U;
if (!(tcp->flags & NET_TCP_RECV_MSS_SET)) {
recv_mss = net_tcp_get_recv_mss(tcp);
tcp->flags |= NET_TCP_RECV_MSS_SET;
} else {
recv_mss = 0U;
}
recv_mss |= (NET_TCP_MSS_OPT << 24) | (NET_TCP_MSS_SIZE << 16);
UNALIGNED_PUT(htonl(recv_mss),
(u32_t *)(options + *optionlen));
*optionlen += NET_TCP_MSS_SIZE;
}
int net_tcp_prepare_ack(struct net_tcp *tcp, const struct sockaddr *remote,
struct net_pkt **pkt)
{
u8_t options[NET_TCP_MAX_OPT_SIZE];
u8_t optionlen;
switch (net_tcp_get_state(tcp)) {
case NET_TCP_SYN_RCVD:
/* In the SYN_RCVD state acknowledgment must be with the
* SYN flag.
*/
net_tcp_set_syn_opt(tcp, options, &optionlen);
return net_tcp_prepare_segment(tcp, NET_TCP_SYN | NET_TCP_ACK,
options, optionlen, NULL, remote,
pkt);
case NET_TCP_FIN_WAIT_1:
case NET_TCP_LAST_ACK:
/* In the FIN_WAIT_1 and LAST_ACK states acknowledgment must
* be with the FIN flag.
*/
return net_tcp_prepare_segment(tcp, NET_TCP_FIN | NET_TCP_ACK,
0, 0, NULL, remote, pkt);
default:
return net_tcp_prepare_segment(tcp, NET_TCP_ACK, 0, 0, NULL,
remote, pkt);
}
return -EINVAL;
}
static inline void copy_sockaddr_to_sockaddr_ptr(struct net_tcp *tcp,
const struct sockaddr *local,
struct sockaddr_ptr *addr)
{
(void)memset(addr, 0, sizeof(struct sockaddr_ptr));
#if defined(CONFIG_NET_IPV4)
if (local->sa_family == AF_INET) {
net_sin_ptr(addr)->sin_family = AF_INET;
net_sin_ptr(addr)->sin_port = net_sin(local)->sin_port;
net_sin_ptr(addr)->sin_addr = &net_sin(local)->sin_addr;
}
#endif
#if defined(CONFIG_NET_IPV6)
if (local->sa_family == AF_INET6) {
net_sin6_ptr(addr)->sin6_family = AF_INET6;
net_sin6_ptr(addr)->sin6_port = net_sin6(local)->sin6_port;
net_sin6_ptr(addr)->sin6_addr = &net_sin6(local)->sin6_addr;
}
#endif
}
int net_tcp_prepare_reset(struct net_tcp *tcp,
const struct sockaddr *local,
const struct sockaddr *remote,
struct net_pkt **pkt)
{
struct tcp_segment segment = { 0 };
int status = 0;
struct sockaddr_ptr src_addr_ptr;
if ((net_context_get_state(tcp->context) != NET_CONTEXT_UNCONNECTED) &&
(net_tcp_get_state(tcp) != NET_TCP_SYN_SENT) &&
(net_tcp_get_state(tcp) != NET_TCP_TIME_WAIT)) {
/* Send the reset segment always with acknowledgment. */
segment.ack = tcp->send_ack;
segment.flags = NET_TCP_RST | NET_TCP_ACK;
segment.seq = tcp->send_seq;
if (!local) {
segment.src_addr = &tcp->context->local;
} else {
copy_sockaddr_to_sockaddr_ptr(tcp, local,
&src_addr_ptr);
segment.src_addr = &src_addr_ptr;
}
segment.dst_addr = remote;
segment.wnd = 0U;
segment.options = NULL;
segment.optlen = 0U;
status = prepare_segment(tcp, &segment, NULL, pkt);
}
return status;
}
const char *net_tcp_state_str(enum net_tcp_state state)
{
#if (CONFIG_NET_TCP_LOG_LEVEL >= LOG_LEVEL_DBG) || defined(CONFIG_NET_SHELL)
switch (state) {
case NET_TCP_CLOSED:
return "CLOSED";
case NET_TCP_LISTEN:
return "LISTEN";
case NET_TCP_SYN_SENT:
return "SYN_SENT";
case NET_TCP_SYN_RCVD:
return "SYN_RCVD";
case NET_TCP_ESTABLISHED:
return "ESTABLISHED";
case NET_TCP_CLOSE_WAIT:
return "CLOSE_WAIT";
case NET_TCP_LAST_ACK:
return "LAST_ACK";
case NET_TCP_FIN_WAIT_1:
return "FIN_WAIT_1";
case NET_TCP_FIN_WAIT_2:
return "FIN_WAIT_2";
case NET_TCP_TIME_WAIT:
return "TIME_WAIT";
case NET_TCP_CLOSING:
return "CLOSING";
}
#else
ARG_UNUSED(state);
#endif
return "";
}
int net_tcp_queue_data(struct net_context *context, struct net_pkt *pkt)
{
struct net_conn *conn = (struct net_conn *)context->conn_handler;
size_t data_len = net_pkt_get_len(pkt);
int ret;
NET_DBG("[%p] Queue %p len %zd", context->tcp, pkt, data_len);
if (net_context_get_state(context) != NET_CONTEXT_CONNECTED) {
return -ENOTCONN;
}
NET_ASSERT(context->tcp);
if (context->tcp->flags & NET_TCP_IS_SHUTDOWN) {
return -ESHUTDOWN;
}
/* Set PSH on all packets, our window is so small that there's
* no point in the remote side trying to finesse things and
* coalesce packets.
*/
ret = net_tcp_prepare_segment(context->tcp, NET_TCP_PSH | NET_TCP_ACK,
NULL, 0, NULL, &conn->remote_addr, &pkt);
if (ret) {
return ret;
}
context->tcp->send_seq += data_len;
net_stats_update_tcp_sent(net_pkt_iface(pkt), data_len);
return net_tcp_queue_pkt(context, pkt);
}
/* This function is the sole point of *adding* packets to tcp->sent_list,
* and should remain such.
*/
static int net_tcp_queue_pkt(struct net_context *context, struct net_pkt *pkt)
{
sys_slist_append(&context->tcp->sent_list, &pkt->sent_list);
/* We need to restart retry_timer if it is stopped. */
if (k_delayed_work_remaining_get(&context->tcp->retry_timer) == 0) {
k_delayed_work_submit(&context->tcp->retry_timer,
retry_timeout(context->tcp));
}
do_ref_if_needed(context->tcp, pkt);
return 0;
}
int net_tcp_send_pkt(struct net_pkt *pkt)
{
NET_PKT_DATA_ACCESS_DEFINE(tcp_access, struct net_tcp_hdr);
struct net_context *ctx = net_pkt_context(pkt);
struct net_tcp_hdr *tcp_hdr;
bool calc_chksum = false;
if (!ctx || !ctx->tcp) {
NET_ERR("%scontext is not set on pkt %p",
!ctx ? "" : "TCP ", pkt);
return -EINVAL;
}
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
if (net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) +
net_pkt_ipv6_ext_len(pkt))) {
return -EMSGSIZE;
}
tcp_hdr = (struct net_tcp_hdr *)net_pkt_get_data(pkt, &tcp_access);
if (!tcp_hdr) {
NET_ERR("Packet %p does not contain TCP header", pkt);
return -EMSGSIZE;
}
if (sys_get_be32(tcp_hdr->ack) != ctx->tcp->send_ack) {
sys_put_be32(ctx->tcp->send_ack, tcp_hdr->ack);
tcp_hdr->chksum = 0U;
calc_chksum = true;
}
/* The data stream code always sets this flag, because
* existing stacks (Linux, anyway) seem to ignore data packets
* without a valid-but-already-transmitted ACK. But set it
* anyway if we know we need it just to sanify edge cases.
*/
if (ctx->tcp->sent_ack != ctx->tcp->send_ack &&
(tcp_hdr->flags & NET_TCP_ACK) == 0U) {
tcp_hdr->flags |= NET_TCP_ACK;
tcp_hdr->chksum = 0U;
calc_chksum = true;
}
/* As we modified the header, we need to write it back.
*/
net_pkt_set_data(pkt, &tcp_access);
if (calc_chksum) {
net_pkt_cursor_init(pkt);
net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) +
net_pkt_ipv6_ext_len(pkt));
/* No need to get tcp_hdr again */
tcp_hdr->chksum = net_calc_chksum_tcp(pkt);
net_pkt_set_data(pkt, &tcp_access);
}
if (tcp_hdr->flags & NET_TCP_FIN) {
ctx->tcp->fin_sent = 1U;
}
ctx->tcp->sent_ack = ctx->tcp->send_ack;
/* We must have special handling for some network technologies that
* tweak the IP protocol headers during packet sending. This happens
* with Bluetooth and IEEE 802.15.4 which use IPv6 header compression
* (6lo) and alter the sent network packet. So in order to avoid any
* corruption of the original data buffer, we must copy the sent data.
* For Bluetooth, its fragmentation code will even mangle the data
* part of the message so we need to copy those too.
*/
if (is_6lo_technology(pkt)) {
struct net_pkt *new_pkt, *check_pkt;
int ret;
bool pkt_in_slist = false;
/*
* There are users of this function that don't add pkt to TCP
* sent_list. (See send_ack() in net_context.c) In these cases,
* we should avoid the extra 6lowpan specific buffer copy
* below.
*/
SYS_SLIST_FOR_EACH_CONTAINER(&ctx->tcp->sent_list,
check_pkt, sent_list) {
if (check_pkt == pkt) {
pkt_in_slist = true;
break;
}
}
if (pkt_in_slist) {
new_pkt = net_pkt_clone(pkt, ALLOC_TIMEOUT);
if (!new_pkt) {
return -ENOMEM;
}
/* This function is called from net_context.c and if we
* return < 0, the caller will unref the original pkt.
* This would leak the new_pkt so remove it here.
*/
ret = net_send_data(new_pkt);
if (ret < 0) {
net_pkt_unref(new_pkt);
} else {
net_stats_update_tcp_seg_rexmit(
net_pkt_iface(pkt));
}
return ret;
}
}
return net_send_data(pkt);
}
static void restart_timer(struct net_tcp *tcp)
{
if (!sys_slist_is_empty(&tcp->sent_list)) {
tcp->flags |= NET_TCP_RETRYING;
tcp->retry_timeout_shift = 0U;
k_delayed_work_submit(&tcp->retry_timer, retry_timeout(tcp));
} else if (CONFIG_NET_TCP_TIME_WAIT_DELAY != 0 &&
(tcp->fin_sent && tcp->fin_rcvd)) {
/* We know sent_list is empty, which means if
* fin_sent is true it must have been ACKd
*/
k_delayed_work_submit(&tcp->retry_timer,
CONFIG_NET_TCP_TIME_WAIT_DELAY);
net_context_ref(tcp->context);
} else {
k_delayed_work_cancel(&tcp->retry_timer);
tcp->flags &= ~NET_TCP_RETRYING;
}
}
int net_tcp_send_data(struct net_context *context, net_context_send_cb_t cb,
void *user_data)
{
struct net_pkt *pkt;
/* For now, just send all queued data synchronously. Need to