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zephyr/subsys/net/ip/tcp.c
Robert Lubos 7deabaa77b net: tcp: Fix possible double TCP context dereferencing 
In case TCP connection is being closed from the TCP stack, due to for
instance retransmission timeout, the stack should also switch the TCP
state to CLOSED. Otherwise, there was a risk of dereferencing the TCP
context twice, for example if the application was in active socket
send(), and tried to reschedule data transmission.

Additionally, make sure that the TCP_CLOSED state handling is a no-op
state - otherwise, there is a risk that if packets keep incoming before
the application dereferences the TCP context on its side, TCP stack
will incorrectly dereference the context for the second time from
within due to current TCP_CLOSED state logic.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
2023-06-06 11:11:22 -04:00

3594 lines
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/*
* Copyright (c) 2018-2020 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(net_tcp, CONFIG_NET_TCP_LOG_LEVEL);
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <zephyr/kernel.h>
#include <zephyr/random/rand32.h>
#if defined(CONFIG_NET_TCP_ISN_RFC6528)
#include <mbedtls/md5.h>
#endif
#include <zephyr/net/net_pkt.h>
#include <zephyr/net/net_context.h>
#include <zephyr/net/udp.h>
#include "ipv4.h"
#include "ipv6.h"
#include "connection.h"
#include "net_stats.h"
#include "net_private.h"
#include "tcp_internal.h"
#define ACK_TIMEOUT_MS CONFIG_NET_TCP_ACK_TIMEOUT
#define ACK_TIMEOUT K_MSEC(ACK_TIMEOUT_MS)
#define FIN_TIMEOUT K_MSEC(tcp_fin_timeout_ms)
#define ACK_DELAY K_MSEC(100)
#define ZWP_MAX_DELAY_MS 120000
#define DUPLICATE_ACK_RETRANSMIT_TRHESHOLD 3
static int tcp_rto = CONFIG_NET_TCP_INIT_RETRANSMISSION_TIMEOUT;
static int tcp_retries = CONFIG_NET_TCP_RETRY_COUNT;
static int tcp_fin_timeout_ms;
static int tcp_rx_window =
#if (CONFIG_NET_TCP_MAX_RECV_WINDOW_SIZE != 0)
CONFIG_NET_TCP_MAX_RECV_WINDOW_SIZE;
#else
#if defined(CONFIG_NET_BUF_FIXED_DATA_SIZE)
(CONFIG_NET_BUF_RX_COUNT * CONFIG_NET_BUF_DATA_SIZE) / 3;
#else
CONFIG_NET_BUF_DATA_POOL_SIZE / 3;
#endif /* CONFIG_NET_BUF_FIXED_DATA_SIZE */
#endif
static int tcp_tx_window =
#if (CONFIG_NET_TCP_MAX_SEND_WINDOW_SIZE != 0)
CONFIG_NET_TCP_MAX_SEND_WINDOW_SIZE;
#else
#if defined(CONFIG_NET_BUF_FIXED_DATA_SIZE)
(CONFIG_NET_BUF_TX_COUNT * CONFIG_NET_BUF_DATA_SIZE) / 3;
#else
CONFIG_NET_BUF_DATA_POOL_SIZE / 3;
#endif /* CONFIG_NET_BUF_FIXED_DATA_SIZE */
#endif
#ifdef CONFIG_NET_TCP_RANDOMIZED_RTO
#define TCP_RTO_MS (conn->rto)
#else
#define TCP_RTO_MS (tcp_rto)
#endif
static sys_slist_t tcp_conns = SYS_SLIST_STATIC_INIT(&tcp_conns);
static K_MUTEX_DEFINE(tcp_lock);
K_MEM_SLAB_DEFINE_STATIC(tcp_conns_slab, sizeof(struct tcp),
CONFIG_NET_MAX_CONTEXTS, 4);
static struct k_work_q tcp_work_q;
static K_KERNEL_STACK_DEFINE(work_q_stack, CONFIG_NET_TCP_WORKQ_STACK_SIZE);
static enum net_verdict tcp_in(struct tcp *conn, struct net_pkt *pkt);
static bool is_destination_local(struct net_pkt *pkt);
static void tcp_out(struct tcp *conn, uint8_t flags);
static const char *tcp_state_to_str(enum tcp_state state, bool prefix);
int (*tcp_send_cb)(struct net_pkt *pkt) = NULL;
size_t (*tcp_recv_cb)(struct tcp *conn, struct net_pkt *pkt) = NULL;
static uint32_t tcp_get_seq(struct net_buf *buf)
{
return *(uint32_t *)net_buf_user_data(buf);
}
static void tcp_set_seq(struct net_buf *buf, uint32_t seq)
{
*(uint32_t *)net_buf_user_data(buf) = seq;
}
static int tcp_pkt_linearize(struct net_pkt *pkt, size_t pos, size_t len)
{
struct net_buf *buf, *first = pkt->cursor.buf, *second = first->frags;
int ret = 0;
size_t len1, len2;
if (net_pkt_get_len(pkt) < (pos + len)) {
NET_ERR("Insufficient packet len=%zd (pos+len=%zu)",
net_pkt_get_len(pkt), pos + len);
ret = -EINVAL;
goto out;
}
buf = net_pkt_get_frag(pkt, len, TCP_PKT_ALLOC_TIMEOUT);
if (!buf || buf->size < len) {
if (buf) {
net_buf_unref(buf);
}
ret = -ENOBUFS;
goto out;
}
net_buf_linearize(buf->data, buf->size, pkt->frags, pos, len);
net_buf_add(buf, len);
len1 = first->len - (pkt->cursor.pos - pkt->cursor.buf->data);
len2 = len - len1;
first->len -= len1;
while (len2) {
size_t pull_len = MIN(second->len, len2);
struct net_buf *next;
len2 -= pull_len;
net_buf_pull(second, pull_len);
next = second->frags;
if (second->len == 0) {
net_buf_unref(second);
}
second = next;
}
buf->frags = second;
first->frags = buf;
out:
return ret;
}
static struct tcphdr *th_get(struct net_pkt *pkt)
{
size_t ip_len = net_pkt_ip_hdr_len(pkt) + net_pkt_ip_opts_len(pkt);
struct tcphdr *th = NULL;
again:
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
if (net_pkt_skip(pkt, ip_len) != 0) {
goto out;
}
if (!net_pkt_is_contiguous(pkt, sizeof(*th))) {
if (tcp_pkt_linearize(pkt, ip_len, sizeof(*th)) < 0) {
goto out;
}
goto again;
}
th = net_pkt_cursor_get_pos(pkt);
out:
return th;
}
static size_t tcp_endpoint_len(sa_family_t af)
{
return (af == AF_INET) ? sizeof(struct sockaddr_in) :
sizeof(struct sockaddr_in6);
}
static int tcp_endpoint_set(union tcp_endpoint *ep, struct net_pkt *pkt,
enum pkt_addr src)
{
int ret = 0;
switch (net_pkt_family(pkt)) {
case AF_INET:
if (IS_ENABLED(CONFIG_NET_IPV4)) {
struct net_ipv4_hdr *ip = NET_IPV4_HDR(pkt);
struct tcphdr *th;
th = th_get(pkt);
if (!th) {
return -ENOBUFS;
}
memset(ep, 0, sizeof(*ep));
ep->sin.sin_port = src == TCP_EP_SRC ? th_sport(th) :
th_dport(th);
net_ipv4_addr_copy_raw((uint8_t *)&ep->sin.sin_addr,
src == TCP_EP_SRC ?
ip->src : ip->dst);
ep->sa.sa_family = AF_INET;
} else {
ret = -EINVAL;
}
break;
case AF_INET6:
if (IS_ENABLED(CONFIG_NET_IPV6)) {
struct net_ipv6_hdr *ip = NET_IPV6_HDR(pkt);
struct tcphdr *th;
th = th_get(pkt);
if (!th) {
return -ENOBUFS;
}
memset(ep, 0, sizeof(*ep));
ep->sin6.sin6_port = src == TCP_EP_SRC ? th_sport(th) :
th_dport(th);
net_ipv6_addr_copy_raw((uint8_t *)&ep->sin6.sin6_addr,
src == TCP_EP_SRC ?
ip->src : ip->dst);
ep->sa.sa_family = AF_INET6;
} else {
ret = -EINVAL;
}
break;
default:
NET_ERR("Unknown address family: %hu", net_pkt_family(pkt));
ret = -EINVAL;
}
return ret;
}
static const char *tcp_flags(uint8_t flags)
{
#define BUF_SIZE 25 /* 6 * 4 + 1 */
static char buf[BUF_SIZE];
int len = 0;
buf[0] = '\0';
if (flags) {
if (flags & SYN) {
len += snprintk(buf + len, BUF_SIZE - len, "SYN,");
}
if (flags & FIN) {
len += snprintk(buf + len, BUF_SIZE - len, "FIN,");
}
if (flags & ACK) {
len += snprintk(buf + len, BUF_SIZE - len, "ACK,");
}
if (flags & PSH) {
len += snprintk(buf + len, BUF_SIZE - len, "PSH,");
}
if (flags & RST) {
len += snprintk(buf + len, BUF_SIZE - len, "RST,");
}
if (flags & URG) {
len += snprintk(buf + len, BUF_SIZE - len, "URG,");
}
if (len > 0) {
buf[len - 1] = '\0'; /* delete the last comma */
}
}
#undef BUF_SIZE
return buf;
}
static size_t tcp_data_len(struct net_pkt *pkt)
{
struct tcphdr *th = th_get(pkt);
size_t tcp_options_len = (th_off(th) - 5) * 4;
int len = net_pkt_get_len(pkt) - net_pkt_ip_hdr_len(pkt) -
net_pkt_ip_opts_len(pkt) - sizeof(*th) - tcp_options_len;
return len > 0 ? (size_t)len : 0;
}
static const char *tcp_th(struct net_pkt *pkt)
{
#define BUF_SIZE 80
static char buf[BUF_SIZE];
int len = 0;
struct tcphdr *th = th_get(pkt);
buf[0] = '\0';
if (th_off(th) < 5) {
len += snprintk(buf + len, BUF_SIZE - len,
"bogus th_off: %hu", (uint16_t)th_off(th));
goto end;
}
len += snprintk(buf + len, BUF_SIZE - len,
"%s Seq=%u", tcp_flags(th_flags(th)), th_seq(th));
if (th_flags(th) & ACK) {
len += snprintk(buf + len, BUF_SIZE - len,
" Ack=%u", th_ack(th));
}
len += snprintk(buf + len, BUF_SIZE - len,
" Len=%ld", (long)tcp_data_len(pkt));
end:
#undef BUF_SIZE
return buf;
}
#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)))
static void tcp_send(struct net_pkt *pkt)
{
NET_DBG("%s", tcp_th(pkt));
tcp_pkt_ref(pkt);
if (tcp_send_cb) {
if (tcp_send_cb(pkt) < 0) {
NET_ERR("net_send_data()");
tcp_pkt_unref(pkt);
}
goto out;
}
/* 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;
new_pkt = tcp_pkt_clone(pkt);
if (!new_pkt) {
/* The caller of this func assumes that the net_pkt
* is consumed by this function. We call unref here
* so that the unref at the end of the func will
* free the net_pkt.
*/
tcp_pkt_unref(pkt);
goto out;
}
if (net_send_data(new_pkt) < 0) {
tcp_pkt_unref(new_pkt);
}
/* We simulate sending of the original pkt and unref it like
* the device driver would do.
*/
tcp_pkt_unref(pkt);
} else {
if (net_send_data(pkt) < 0) {
NET_ERR("net_send_data()");
tcp_pkt_unref(pkt);
}
}
out:
tcp_pkt_unref(pkt);
}
static void tcp_derive_rto(struct tcp *conn)
{
#ifdef CONFIG_NET_TCP_RANDOMIZED_RTO
/* Compute a randomized rto 1 and 1.5 times tcp_rto */
uint32_t gain;
uint8_t gain8;
uint32_t rto;
/* Getting random is computational expensive, so only use 8 bits */
sys_rand_get(&gain8, sizeof(uint8_t));
gain = (uint32_t)gain8;
gain += 1 << 9;
rto = (uint32_t)tcp_rto;
rto = (gain * rto) >> 9;
conn->rto = (uint16_t)rto;
#else
ARG_UNUSED(conn);
#endif
}
static void tcp_send_queue_flush(struct tcp *conn)
{
struct net_pkt *pkt;
k_work_cancel_delayable(&conn->send_timer);
while ((pkt = tcp_slist(conn, &conn->send_queue, get,
struct net_pkt, next))) {
tcp_pkt_unref(pkt);
}
}
static int tcp_conn_unref(struct tcp *conn)
{
int ref_count = atomic_get(&conn->ref_count);
struct net_pkt *pkt;
NET_DBG("conn: %p, ref_count=%d", conn, ref_count);
k_mutex_lock(&conn->lock, K_FOREVER);
#if !defined(CONFIG_NET_TEST_PROTOCOL)
if (conn->in_connect) {
conn->in_connect = false;
k_sem_reset(&conn->connect_sem);
}
#endif /* CONFIG_NET_TEST_PROTOCOL */
k_mutex_unlock(&conn->lock);
ref_count = atomic_dec(&conn->ref_count) - 1;
if (ref_count != 0) {
tp_out(net_context_get_family(conn->context), conn->iface,
"TP_TRACE", "event", "CONN_DELETE");
return ref_count;
}
k_mutex_lock(&tcp_lock, K_FOREVER);
/* If there is any pending data, pass that to application */
while ((pkt = k_fifo_get(&conn->recv_data, K_NO_WAIT)) != NULL) {
if (net_context_packet_received(
(struct net_conn *)conn->context->conn_handler,
pkt, NULL, NULL, conn->recv_user_data) ==
NET_DROP) {
/* Application is no longer there, unref the pkt */
tcp_pkt_unref(pkt);
}
}
if (conn->context->conn_handler) {
net_conn_unregister(conn->context->conn_handler);
conn->context->conn_handler = NULL;
}
conn->context->tcp = NULL;
net_context_unref(conn->context);
tcp_send_queue_flush(conn);
k_work_cancel_delayable(&conn->send_data_timer);
tcp_pkt_unref(conn->send_data);
if (CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT) {
tcp_pkt_unref(conn->queue_recv_data);
}
(void)k_work_cancel_delayable(&conn->timewait_timer);
(void)k_work_cancel_delayable(&conn->fin_timer);
(void)k_work_cancel_delayable(&conn->persist_timer);
(void)k_work_cancel_delayable(&conn->ack_timer);
sys_slist_find_and_remove(&tcp_conns, &conn->next);
memset(conn, 0, sizeof(*conn));
k_mem_slab_free(&tcp_conns_slab, (void **)&conn);
k_mutex_unlock(&tcp_lock);
return ref_count;
}
#if CONFIG_NET_TCP_LOG_LEVEL >= LOG_LEVEL_DBG
#define tcp_conn_close(conn, status) \
tcp_conn_close_debug(conn, status, __func__, __LINE__)
static int tcp_conn_close_debug(struct tcp *conn, int status,
const char *caller, int line)
#else
static int tcp_conn_close(struct tcp *conn, int status)
#endif
{
#if CONFIG_NET_TCP_LOG_LEVEL >= LOG_LEVEL_DBG
NET_DBG("conn: %p closed by TCP stack (%s():%d)", conn, caller, line);
#endif
k_mutex_lock(&conn->lock, K_FOREVER);
conn_state(conn, TCP_CLOSED);
k_mutex_unlock(&conn->lock);
if (conn->in_connect) {
if (conn->connect_cb) {
conn->connect_cb(conn->context, status, conn->context->user_data);
/* Make sure the connect_cb is only called once. */
conn->connect_cb = NULL;
}
} else if (conn->context->recv_cb) {
conn->context->recv_cb(conn->context, NULL, NULL, NULL,
status, conn->recv_user_data);
}
return tcp_conn_unref(conn);
}
static bool tcp_send_process_no_lock(struct tcp *conn)
{
bool unref = false;
struct net_pkt *pkt;
bool local = false;
pkt = tcp_slist(conn, &conn->send_queue, peek_head,
struct net_pkt, next);
if (!pkt) {
goto out;
}
NET_DBG("%s %s", tcp_th(pkt), conn->in_retransmission ?
"in_retransmission" : "");
if (conn->in_retransmission) {
if (conn->send_retries > 0) {
struct net_pkt *clone = tcp_pkt_clone(pkt);
if (clone) {
tcp_send(clone);
conn->send_retries--;
}
} else {
unref = true;
goto out;
}
} else {
uint8_t fl = th_get(pkt)->th_flags;
bool forget = ACK == fl || PSH == fl || (ACK | PSH) == fl ||
RST & fl;
pkt = forget ? tcp_slist(conn, &conn->send_queue, get,
struct net_pkt, next) :
tcp_pkt_clone(pkt);
if (!pkt) {
NET_ERR("net_pkt alloc failure");
goto out;
}
if (is_destination_local(pkt)) {
local = true;
}
tcp_send(pkt);
if (forget == false &&
!k_work_delayable_remaining_get(&conn->send_timer)) {
conn->send_retries = tcp_retries;
conn->in_retransmission = true;
}
}
if (conn->in_retransmission) {
k_work_reschedule_for_queue(&tcp_work_q, &conn->send_timer,
K_MSEC(TCP_RTO_MS));
} else if (local && !sys_slist_is_empty(&conn->send_queue)) {
k_work_reschedule_for_queue(&tcp_work_q, &conn->send_timer,
K_NO_WAIT);
}
out:
return unref;
}
static void tcp_send_process(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, send_timer);
bool unref;
k_mutex_lock(&conn->lock, K_FOREVER);
unref = tcp_send_process_no_lock(conn);
k_mutex_unlock(&conn->lock);
if (unref) {
tcp_conn_close(conn, -ETIMEDOUT);
}
}
static void tcp_send_timer_cancel(struct tcp *conn)
{
if (conn->in_retransmission == false) {
return;
}
k_work_cancel_delayable(&conn->send_timer);
{
struct net_pkt *pkt = tcp_slist(conn, &conn->send_queue, get,
struct net_pkt, next);
if (pkt) {
NET_DBG("%s", tcp_th(pkt));
tcp_pkt_unref(pkt);
}
}
if (sys_slist_is_empty(&conn->send_queue)) {
conn->in_retransmission = false;
} else {
conn->send_retries = tcp_retries;
k_work_reschedule_for_queue(&tcp_work_q, &conn->send_timer,
K_MSEC(TCP_RTO_MS));
}
}
static const char *tcp_state_to_str(enum tcp_state state, bool prefix)
{
const char *s = NULL;
#define _(_x) case _x: do { s = #_x; goto out; } while (0)
switch (state) {
_(TCP_LISTEN);
_(TCP_SYN_SENT);
_(TCP_SYN_RECEIVED);
_(TCP_ESTABLISHED);
_(TCP_FIN_WAIT_1);
_(TCP_FIN_WAIT_2);
_(TCP_CLOSE_WAIT);
_(TCP_CLOSING);
_(TCP_LAST_ACK);
_(TCP_TIME_WAIT);
_(TCP_CLOSED);
}
#undef _
NET_ASSERT(s, "Invalid TCP state: %u", state);
out:
return prefix ? s : (s + 4);
}
static const char *tcp_conn_state(struct tcp *conn, struct net_pkt *pkt)
{
#define BUF_SIZE 160
static char buf[BUF_SIZE];
snprintk(buf, BUF_SIZE, "%s [%s Seq=%u Ack=%u]", pkt ? tcp_th(pkt) : "",
tcp_state_to_str(conn->state, false),
conn->seq, conn->ack);
#undef BUF_SIZE
return buf;
}
static uint8_t *tcp_options_get(struct net_pkt *pkt, int tcp_options_len,
uint8_t *buf, size_t buf_len)
{
struct net_pkt_cursor backup;
int ret;
net_pkt_cursor_backup(pkt, &backup);
net_pkt_cursor_init(pkt);
net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) + net_pkt_ip_opts_len(pkt) +
sizeof(struct tcphdr));
ret = net_pkt_read(pkt, buf, MIN(tcp_options_len, buf_len));
if (ret < 0) {
buf = NULL;
}
net_pkt_cursor_restore(pkt, &backup);
return buf;
}
static bool tcp_options_check(struct tcp_options *recv_options,
struct net_pkt *pkt, ssize_t len)
{
uint8_t options_buf[40]; /* TCP header max options size is 40 */
bool result = len > 0 && ((len % 4) == 0) ? true : false;
uint8_t *options = tcp_options_get(pkt, len, options_buf,
sizeof(options_buf));
uint8_t opt, opt_len;
NET_DBG("len=%zd", len);
recv_options->mss_found = false;
recv_options->wnd_found = false;
for ( ; options && len >= 1; options += opt_len, len -= opt_len) {
opt = options[0];
if (opt == NET_TCP_END_OPT) {
break;
} else if (opt == NET_TCP_NOP_OPT) {
opt_len = 1;
continue;
} else {
if (len < 2) { /* Only END and NOP can have length 1 */
NET_ERR("Illegal option %d with length %zd",
opt, len);
result = false;
break;
}
opt_len = options[1];
}
NET_DBG("opt: %hu, opt_len: %hu",
(uint16_t)opt, (uint16_t)opt_len);
if (opt_len < 2 || opt_len > len) {
result = false;
break;
}
switch (opt) {
case NET_TCP_MSS_OPT:
if (opt_len != 4) {
result = false;
goto end;
}
recv_options->mss =
ntohs(UNALIGNED_GET((uint16_t *)(options + 2)));
recv_options->mss_found = true;
NET_DBG("MSS=%hu", recv_options->mss);
break;
case NET_TCP_WINDOW_SCALE_OPT:
if (opt_len != 3) {
result = false;
goto end;
}
recv_options->window = opt;
recv_options->wnd_found = true;
break;
default:
continue;
}
}
end:
if (false == result) {
NET_WARN("Invalid TCP options");
}
return result;
}
static bool tcp_short_window(struct tcp *conn)
{
int32_t threshold = MIN(conn_mss(conn), conn->recv_win_max / 2);
if (conn->recv_win > threshold) {
return false;
}
return true;
}
/**
* @brief Update TCP receive window
*
* @param conn TCP network connection
* @param delta Receive window delta
*
* @return 0 on success, -EINVAL
* if the receive window delta is out of bounds
*/
static int tcp_update_recv_wnd(struct tcp *conn, int32_t delta)
{
int32_t new_win;
bool short_win_before;
bool short_win_after;
new_win = conn->recv_win + delta;
if (new_win < 0) {
new_win = 0;
} else if (new_win > conn->recv_win_max) {
new_win = conn->recv_win_max;
}
short_win_before = tcp_short_window(conn);
conn->recv_win = new_win;
short_win_after = tcp_short_window(conn);
if (short_win_before && !short_win_after &&
conn->state == TCP_ESTABLISHED) {
k_work_cancel_delayable(&conn->ack_timer);
tcp_out(conn, ACK);
}
return 0;
}
static size_t tcp_check_pending_data(struct tcp *conn, struct net_pkt *pkt,
size_t len)
{
size_t pending_len = 0;
if (CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT &&
!net_pkt_is_empty(conn->queue_recv_data)) {
/* Some potentential cases:
* Note: MI = MAX_INT
* Packet | Queued| End off | Gap size | Required handling
* Seq|Len|Seq|Len| | |
* 3 | 3 | 6 | 4 | 3+3-6= 0 | 6-3-3=0 | Append
* 3 | 4 | 6 | 4 | 3+4-6 = 1 | 6-3-4=-1 | Append, pull from queue
* 3 | 7 | 6 | 4 | 3+7-6 = 4 | 6-3-7=-4 | Drop queued data
* 3 | 8 | 6 | 4 | 3+8-6 = 5 | 6-3-8=-5 | Drop queued data
* 6 | 5 | 6 | 4 | 6+5-6 = 5 | 6-6-5=-5 | Drop queued data
* 6 | 4 | 6 | 4 | 6+4-6 = 4 | 6-6-4=-4 | Drop queued data / packet
* 10 | 2 | 6 | 4 | 10+2-6= 6 | 6-10-2=-6| Should not happen, dropping queue
* 7 | 4 | 6 | 4 | 7+4-6 = 5 | 6-7-4=-5 | Should not happen, dropping queue
* 11 | 2 | 6 | 4 | 11+2-6= 7 | 6-11-2=-7| Should not happen, dropping queue
* 2 | 3 | 6 | 4 | 2+3-6= MI | 6-2-3=1 | Keep queued data
*/
struct tcphdr *th = th_get(pkt);
uint32_t expected_seq = th_seq(th) + len;
uint32_t pending_seq;
int32_t gap_size;
uint32_t end_offset;
pending_seq = tcp_get_seq(conn->queue_recv_data->buffer);
end_offset = expected_seq - pending_seq;
gap_size = (int32_t)(pending_seq - th_seq(th) - ((uint32_t)len));
pending_len = net_pkt_get_len(conn->queue_recv_data);
if (end_offset < pending_len) {
if (end_offset) {
net_pkt_remove_tail(pkt, end_offset);
pending_len -= end_offset;
}
NET_DBG("Found pending data seq %u len %zd",
expected_seq, pending_len);
net_buf_frag_add(pkt->buffer,
conn->queue_recv_data->buffer);
conn->queue_recv_data->buffer = NULL;
k_work_cancel_delayable(&conn->recv_queue_timer);
} else {
/* Check if the queued data is just a section of the incoming data */
if (gap_size <= 0) {
net_buf_unref(conn->queue_recv_data->buffer);
conn->queue_recv_data->buffer = NULL;
k_work_cancel_delayable(&conn->recv_queue_timer);
}
pending_len = 0;
}
}
return pending_len;
}
static enum net_verdict tcp_data_get(struct tcp *conn, struct net_pkt *pkt, size_t *len)
{
enum net_verdict ret = NET_DROP;
if (tcp_recv_cb) {
tcp_recv_cb(conn, pkt);
goto out;
}
if (conn->context->recv_cb) {
/* If there is any out-of-order pending data, then pass it
* to the application here.
*/
*len += tcp_check_pending_data(conn, pkt, *len);
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
net_pkt_skip(pkt, net_pkt_get_len(pkt) - *len);
tcp_update_recv_wnd(conn, -*len);
/* Do not pass data to application with TCP conn
* locked as there could be an issue when the app tries
* to send the data and the conn is locked. So the recv
* data is placed in fifo which is flushed in tcp_in()
* after unlocking the conn
*/
k_fifo_put(&conn->recv_data, pkt);
ret = NET_OK;
}
out:
return ret;
}
static int tcp_finalize_pkt(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);
}
if (IS_ENABLED(CONFIG_NET_IPV6) && net_pkt_family(pkt) == AF_INET6) {
return net_ipv6_finalize(pkt, IPPROTO_TCP);
}
return -EINVAL;
}
static int tcp_header_add(struct tcp *conn, struct net_pkt *pkt, uint8_t flags,
uint32_t seq)
{
NET_PKT_DATA_ACCESS_DEFINE(tcp_access, struct tcphdr);
struct tcphdr *th;
th = (struct tcphdr *)net_pkt_get_data(pkt, &tcp_access);
if (!th) {
return -ENOBUFS;
}
memset(th, 0, sizeof(struct tcphdr));
UNALIGNED_PUT(conn->src.sin.sin_port, &th->th_sport);
UNALIGNED_PUT(conn->dst.sin.sin_port, &th->th_dport);
th->th_off = 5;
if (conn->send_options.mss_found) {
th->th_off++;
}
UNALIGNED_PUT(flags, &th->th_flags);
UNALIGNED_PUT(htons(conn->recv_win), &th->th_win);
UNALIGNED_PUT(htonl(seq), &th->th_seq);
if (ACK & flags) {
UNALIGNED_PUT(htonl(conn->ack), &th->th_ack);
}
return net_pkt_set_data(pkt, &tcp_access);
}
static int ip_header_add(struct tcp *conn, struct net_pkt *pkt)
{
if (IS_ENABLED(CONFIG_NET_IPV4) && net_pkt_family(pkt) == AF_INET) {
return net_context_create_ipv4_new(conn->context, pkt,
&conn->src.sin.sin_addr,
&conn->dst.sin.sin_addr);
}
if (IS_ENABLED(CONFIG_NET_IPV6) && net_pkt_family(pkt) == AF_INET6) {
return net_context_create_ipv6_new(conn->context, pkt,
&conn->src.sin6.sin6_addr,
&conn->dst.sin6.sin6_addr);
}
return -EINVAL;
}
static int set_tcp_nodelay(struct tcp *conn, const void *value, size_t len)
{
int no_delay_int;
if (len != sizeof(int)) {
return -EINVAL;
}
no_delay_int = *(int *)value;
if ((no_delay_int < 0) || (no_delay_int > 1)) {
return -EINVAL;
}
conn->tcp_nodelay = (bool)no_delay_int;
return 0;
}
static int get_tcp_nodelay(struct tcp *conn, void *value, size_t *len)
{
int no_delay_int = (int)conn->tcp_nodelay;
*((int *)value) = no_delay_int;
if (len) {
*len = sizeof(int);
}
return 0;
}
static int net_tcp_set_mss_opt(struct tcp *conn, struct net_pkt *pkt)
{
NET_PKT_DATA_ACCESS_DEFINE(mss_opt_access, struct tcp_mss_option);
struct tcp_mss_option *mss;
uint32_t recv_mss;
mss = net_pkt_get_data(pkt, &mss_opt_access);
if (!mss) {
return -ENOBUFS;
}
recv_mss = net_tcp_get_supported_mss(conn);
recv_mss |= (NET_TCP_MSS_OPT << 24) | (NET_TCP_MSS_SIZE << 16);
UNALIGNED_PUT(htonl(recv_mss), (uint32_t *)mss);
return net_pkt_set_data(pkt, &mss_opt_access);
}
static bool is_destination_local(struct net_pkt *pkt)
{
if (IS_ENABLED(CONFIG_NET_IPV4) && net_pkt_family(pkt) == AF_INET) {
if (net_ipv4_is_addr_loopback(
(struct in_addr *)NET_IPV4_HDR(pkt)->dst) ||
net_ipv4_is_my_addr(
(struct in_addr *)NET_IPV4_HDR(pkt)->dst)) {
return true;
}
}
if (IS_ENABLED(CONFIG_NET_IPV6) && net_pkt_family(pkt) == AF_INET6) {
if (net_ipv6_is_addr_loopback(
(struct in6_addr *)NET_IPV6_HDR(pkt)->dst) ||
net_ipv6_is_my_addr(
(struct in6_addr *)NET_IPV6_HDR(pkt)->dst)) {
return true;
}
}
return false;
}
static int tcp_out_ext(struct tcp *conn, uint8_t flags, struct net_pkt *data,
uint32_t seq)
{
size_t alloc_len = sizeof(struct tcphdr);
struct net_pkt *pkt;
int ret = 0;
if (conn->send_options.mss_found) {
alloc_len += sizeof(uint32_t);
}
pkt = tcp_pkt_alloc(conn, alloc_len);
if (!pkt) {
ret = -ENOBUFS;
goto out;
}
if (data) {
/* Append the data buffer to the pkt */
net_pkt_append_buffer(pkt, data->buffer);
data->buffer = NULL;
}
ret = ip_header_add(conn, pkt);
if (ret < 0) {
tcp_pkt_unref(pkt);
goto out;
}
ret = tcp_header_add(conn, pkt, flags, seq);
if (ret < 0) {
tcp_pkt_unref(pkt);
goto out;
}
if (conn->send_options.mss_found) {
ret = net_tcp_set_mss_opt(conn, pkt);
if (ret < 0) {
tcp_pkt_unref(pkt);
goto out;
}
}
ret = tcp_finalize_pkt(pkt);
if (ret < 0) {
tcp_pkt_unref(pkt);
goto out;
}
NET_DBG("%s", tcp_th(pkt));
if (tcp_send_cb) {
ret = tcp_send_cb(pkt);
goto out;
}
sys_slist_append(&conn->send_queue, &pkt->next);
if (is_destination_local(pkt)) {
/* If the destination is local, we have to let the current
* thread to finish with any state-machine changes before
* sending the packet, or it might lead to state inconsistencies
*/
k_work_schedule_for_queue(&tcp_work_q,
&conn->send_timer, K_NO_WAIT);
} else if (tcp_send_process_no_lock(conn)) {
tcp_conn_close(conn, -ETIMEDOUT);
}
out:
return ret;
}
static void tcp_out(struct tcp *conn, uint8_t flags)
{
(void)tcp_out_ext(conn, flags, NULL /* no data */, conn->seq);
}
static int tcp_pkt_pull(struct net_pkt *pkt, size_t len)
{
int total = net_pkt_get_len(pkt);
int ret = 0;
if (len > total) {
ret = -EINVAL;
goto out;
}
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
net_pkt_pull(pkt, len);
net_pkt_trim_buffer(pkt);
out:
return ret;
}
static int tcp_pkt_peek(struct net_pkt *to, struct net_pkt *from, size_t pos,
size_t len)
{
net_pkt_cursor_init(to);
net_pkt_cursor_init(from);
if (pos) {
net_pkt_set_overwrite(from, true);
net_pkt_skip(from, pos);
}
return net_pkt_copy(to, from, len);
}
static bool tcp_window_full(struct tcp *conn)
{
bool window_full = (conn->send_data_total >= conn->send_win);
NET_DBG("conn: %p window_full=%hu", conn, window_full);
return window_full;
}
static int tcp_unsent_len(struct tcp *conn)
{
int unsent_len;
if (conn->unacked_len > conn->send_data_total) {
NET_ERR("total=%zu, unacked_len=%d",
conn->send_data_total, conn->unacked_len);
unsent_len = -ERANGE;
goto out;
}
unsent_len = conn->send_data_total - conn->unacked_len;
if (conn->unacked_len >= conn->send_win) {
unsent_len = 0;
} else {
unsent_len = MIN(unsent_len, conn->send_win - conn->unacked_len);
}
out:
NET_DBG("unsent_len=%d", unsent_len);
return unsent_len;
}
static int tcp_send_data(struct tcp *conn)
{
int ret = 0;
int len;
struct net_pkt *pkt;
len = MIN3(conn->send_data_total - conn->unacked_len,
conn->send_win - conn->unacked_len,
conn_mss(conn));
if (len == 0) {
NET_DBG("conn: %p no data to send", conn);
ret = -ENODATA;
goto out;
}
pkt = tcp_pkt_alloc(conn, len);
if (!pkt) {
NET_ERR("conn: %p packet allocation failed, len=%d", conn, len);
ret = -ENOBUFS;
goto out;
}
ret = tcp_pkt_peek(pkt, conn->send_data, conn->unacked_len, len);
if (ret < 0) {
tcp_pkt_unref(pkt);
ret = -ENOBUFS;
goto out;
}
ret = tcp_out_ext(conn, PSH | ACK, pkt, conn->seq + conn->unacked_len);
if (ret == 0) {
conn->unacked_len += len;
if (conn->data_mode == TCP_DATA_MODE_RESEND) {
net_stats_update_tcp_resent(conn->iface, len);
net_stats_update_tcp_seg_rexmit(conn->iface);
} else {
net_stats_update_tcp_sent(conn->iface, len);
net_stats_update_tcp_seg_sent(conn->iface);
}
}
/* The data we want to send, has been moved to the send queue so we
* can unref the head net_pkt. If there was an error, we need to remove
* the packet anyway.
*/
tcp_pkt_unref(pkt);
conn_send_data_dump(conn);
out:
return ret;
}
/* Send all queued but unsent data from the send_data packet by packet
* until the receiver's window is full. */
static int tcp_send_queued_data(struct tcp *conn)
{
int ret = 0;
bool subscribe = false;
if (conn->data_mode == TCP_DATA_MODE_RESEND) {
goto out;
}
while (tcp_unsent_len(conn) > 0) {
/* Implement Nagle's algorithm */
if ((conn->tcp_nodelay == false) && (conn->unacked_len > 0)) {
/* If there is already pending data */
if (tcp_unsent_len(conn) < conn_mss(conn)) {
/* The number of bytes to be transmitted is less than an MSS,
* skip transmission for now.
* Wait for more data to be transmitted or all pending data
* being acknowledged.
*/
break;
}
}
ret = tcp_send_data(conn);
if (ret < 0) {
break;
}
}
if (conn->send_data_total) {
subscribe = true;
}
if (k_work_delayable_remaining_get(&conn->send_data_timer)) {
subscribe = false;
}
if (subscribe) {
conn->send_data_retries = 0;
k_work_reschedule_for_queue(&tcp_work_q, &conn->send_data_timer,
K_MSEC(TCP_RTO_MS));
}
out:
return ret;
}
static void tcp_cleanup_recv_queue(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, recv_queue_timer);
k_mutex_lock(&conn->lock, K_FOREVER);
NET_DBG("Cleanup recv queue conn %p len %zd seq %u", conn,
net_pkt_get_len(conn->queue_recv_data),
tcp_get_seq(conn->queue_recv_data->buffer));
net_buf_unref(conn->queue_recv_data->buffer);
conn->queue_recv_data->buffer = NULL;
k_mutex_unlock(&conn->lock);
}
static void tcp_resend_data(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, send_data_timer);
bool conn_unref = false;
int ret;
int exp_tcp_rto;
k_mutex_lock(&conn->lock, K_FOREVER);
NET_DBG("send_data_retries=%hu", conn->send_data_retries);
if (conn->send_data_retries >= tcp_retries) {
NET_DBG("conn: %p close, data retransmissions exceeded", conn);
conn_unref = true;
goto out;
}
conn->data_mode = TCP_DATA_MODE_RESEND;
conn->unacked_len = 0;
ret = tcp_send_data(conn);
conn->send_data_retries++;
if (ret == 0) {
if (conn->in_close && conn->send_data_total == 0) {
NET_DBG("TCP connection in active close, "
"not disposing yet (waiting %dms)",
tcp_fin_timeout_ms);
k_work_reschedule_for_queue(&tcp_work_q,
&conn->fin_timer,
FIN_TIMEOUT);
conn_state(conn, TCP_FIN_WAIT_1);
ret = tcp_out_ext(conn, FIN | ACK, NULL,
conn->seq + conn->unacked_len);
if (ret == 0) {
conn_seq(conn, + 1);
}
goto out;
}
} else if (ret == -ENODATA) {
conn->data_mode = TCP_DATA_MODE_SEND;
goto out;
} else if (ret == -ENOBUFS) {
NET_ERR("TCP failed to allocate buffer in retransmission");
}
exp_tcp_rto = TCP_RTO_MS;
/* The last retransmit does not need to wait that long */
if (conn->send_data_retries < tcp_retries) {
/* Every retransmit, the retransmission timeout increases by a factor 1.5 */
for (int i = 0; i < conn->send_data_retries; i++) {
exp_tcp_rto += exp_tcp_rto >> 1;
}
}
k_work_reschedule_for_queue(&tcp_work_q, &conn->send_data_timer,
K_MSEC(exp_tcp_rto));
out:
k_mutex_unlock(&conn->lock);
if (conn_unref) {
tcp_conn_close(conn, -ETIMEDOUT);
}
}
static void tcp_timewait_timeout(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, timewait_timer);
NET_DBG("conn: %p %s", conn, tcp_conn_state(conn, NULL));
(void)tcp_conn_close(conn, -ETIMEDOUT);
}
static void tcp_establish_timeout(struct tcp *conn)
{
NET_DBG("Did not receive %s in %dms", "ACK", ACK_TIMEOUT_MS);
NET_DBG("conn: %p %s", conn, tcp_conn_state(conn, NULL));
(void)tcp_conn_close(conn, -ETIMEDOUT);
}
static void tcp_fin_timeout(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, fin_timer);
if (conn->state == TCP_SYN_RECEIVED) {
tcp_establish_timeout(conn);
return;
}
NET_DBG("Did not receive %s in %dms", "FIN", tcp_fin_timeout_ms);
NET_DBG("conn: %p %s", conn, tcp_conn_state(conn, NULL));
(void)tcp_conn_close(conn, -ETIMEDOUT);
}
static void tcp_send_zwp(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, persist_timer);
k_mutex_lock(&conn->lock, K_FOREVER);
(void)tcp_out_ext(conn, ACK, NULL, conn->seq - 1);
tcp_derive_rto(conn);
if (conn->send_win == 0) {
uint64_t timeout = TCP_RTO_MS;
/* Make sure the bitwise shift does not result in undefined behaviour */
if (conn->zwp_retries < 63) {
conn->zwp_retries++;
}
timeout <<= conn->zwp_retries;
if (timeout == 0 || timeout > ZWP_MAX_DELAY_MS) {
timeout = ZWP_MAX_DELAY_MS;
}
(void)k_work_reschedule_for_queue(
&tcp_work_q, &conn->persist_timer, K_MSEC(timeout));
}
k_mutex_unlock(&conn->lock);
}
static void tcp_send_ack(struct k_work *work)
{
struct k_work_delayable *dwork = k_work_delayable_from_work(work);
struct tcp *conn = CONTAINER_OF(dwork, struct tcp, ack_timer);
k_mutex_lock(&conn->lock, K_FOREVER);
tcp_out(conn, ACK);
k_mutex_unlock(&conn->lock);
}
static void tcp_conn_ref(struct tcp *conn)
{
int ref_count = atomic_inc(&conn->ref_count) + 1;
NET_DBG("conn: %p, ref_count: %d", conn, ref_count);
}
static struct tcp *tcp_conn_alloc(void)
{
struct tcp *conn = NULL;
int ret;
ret = k_mem_slab_alloc(&tcp_conns_slab, (void **)&conn, K_NO_WAIT);
if (ret) {
NET_ERR("Cannot allocate slab");
goto out;
}
memset(conn, 0, sizeof(*conn));
if (CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT) {
conn->queue_recv_data = tcp_rx_pkt_alloc(conn, 0);
if (conn->queue_recv_data == NULL) {
NET_ERR("Cannot allocate %s queue for conn %p", "recv",
conn);
goto fail;
}
}
conn->send_data = tcp_pkt_alloc(conn, 0);
if (conn->send_data == NULL) {
NET_ERR("Cannot allocate %s queue for conn %p", "send", conn);
goto fail;
}
k_mutex_init(&conn->lock);
k_fifo_init(&conn->recv_data);
k_sem_init(&conn->connect_sem, 0, K_SEM_MAX_LIMIT);
k_sem_init(&conn->tx_sem, 1, 1);
conn->in_connect = false;
conn->state = TCP_LISTEN;
conn->recv_win_max = tcp_rx_window;
conn->recv_win = conn->recv_win_max;
conn->send_win_max = MAX(tcp_tx_window, NET_IPV6_MTU);
conn->send_win = conn->send_win_max;
conn->tcp_nodelay = false;
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
conn->dup_ack_cnt = 0;
#endif
/* The ISN value will be set when we get the connection attempt or
* when trying to create a connection.
*/
conn->seq = 0U;
sys_slist_init(&conn->send_queue);
k_work_init_delayable(&conn->send_timer, tcp_send_process);
k_work_init_delayable(&conn->timewait_timer, tcp_timewait_timeout);
k_work_init_delayable(&conn->fin_timer, tcp_fin_timeout);
k_work_init_delayable(&conn->send_data_timer, tcp_resend_data);
k_work_init_delayable(&conn->recv_queue_timer, tcp_cleanup_recv_queue);
k_work_init_delayable(&conn->persist_timer, tcp_send_zwp);
k_work_init_delayable(&conn->ack_timer, tcp_send_ack);
tcp_conn_ref(conn);
sys_slist_append(&tcp_conns, &conn->next);
out:
NET_DBG("conn: %p", conn);
return conn;
fail:
if (CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT && conn->queue_recv_data) {
tcp_pkt_unref(conn->queue_recv_data);
conn->queue_recv_data = NULL;
}
k_mem_slab_free(&tcp_conns_slab, (void **)&conn);
return NULL;
}
int net_tcp_get(struct net_context *context)
{
int ret = 0;
struct tcp *conn;
k_mutex_lock(&tcp_lock, K_FOREVER);
conn = tcp_conn_alloc();
if (conn == NULL) {
ret = -ENOMEM;
goto out;
}
/* Mutually link the net_context and tcp connection */
conn->context = context;
context->tcp = conn;
out:
k_mutex_unlock(&tcp_lock);
return ret;
}
static bool tcp_endpoint_cmp(union tcp_endpoint *ep, struct net_pkt *pkt,
enum pkt_addr which)
{
union tcp_endpoint ep_tmp;
if (tcp_endpoint_set(&ep_tmp, pkt, which) < 0) {
return false;
}
return !memcmp(ep, &ep_tmp, tcp_endpoint_len(ep->sa.sa_family));
}
static bool tcp_conn_cmp(struct tcp *conn, struct net_pkt *pkt)
{
return tcp_endpoint_cmp(&conn->src, pkt, TCP_EP_DST) &&
tcp_endpoint_cmp(&conn->dst, pkt, TCP_EP_SRC);
}
static struct tcp *tcp_conn_search(struct net_pkt *pkt)
{
bool found = false;
struct tcp *conn;
struct tcp *tmp;
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&tcp_conns, conn, tmp, next) {
found = tcp_conn_cmp(conn, pkt);
if (found) {
break;
}
}
return found ? conn : NULL;
}
static struct tcp *tcp_conn_new(struct net_pkt *pkt);
static enum net_verdict tcp_recv(struct net_conn *net_conn,
struct net_pkt *pkt,
union net_ip_header *ip,
union net_proto_header *proto,
void *user_data)
{
struct tcp *conn;
struct tcphdr *th;
enum net_verdict verdict = NET_DROP;
ARG_UNUSED(net_conn);
ARG_UNUSED(proto);
conn = tcp_conn_search(pkt);
if (conn) {
goto in;
}
th = th_get(pkt);
if (th_flags(th) & SYN && !(th_flags(th) & ACK)) {
struct tcp *conn_old = ((struct net_context *)user_data)->tcp;
conn = tcp_conn_new(pkt);
if (!conn) {
NET_ERR("Cannot allocate a new TCP connection");
goto in;
}
net_ipaddr_copy(&conn_old->context->remote, &conn->dst.sa);
conn->accepted_conn = conn_old;
}
in:
if (conn) {
verdict = tcp_in(conn, pkt);
}
return verdict;
}
static uint32_t seq_scale(uint32_t seq)
{
return seq + (k_ticks_to_ns_floor32(k_uptime_ticks()) >> 6);
}
static uint8_t unique_key[16]; /* MD5 128 bits as described in RFC6528 */
static uint32_t tcpv6_init_isn(struct in6_addr *saddr,
struct in6_addr *daddr,
uint16_t sport,
uint16_t dport)
{
struct {
uint8_t key[sizeof(unique_key)];
struct in6_addr saddr;
struct in6_addr daddr;
uint16_t sport;
uint16_t dport;
} buf = {
.saddr = *(struct in6_addr *)saddr,
.daddr = *(struct in6_addr *)daddr,
.sport = sport,
.dport = dport
};
uint8_t hash[16];
static bool once;
if (!once) {
sys_rand_get(unique_key, sizeof(unique_key));
once = true;
}
memcpy(buf.key, unique_key, sizeof(buf.key));
#if defined(CONFIG_NET_TCP_ISN_RFC6528)
mbedtls_md5((const unsigned char *)&buf, sizeof(buf), hash);
#endif
return seq_scale(UNALIGNED_GET((uint32_t *)&hash[0]));
}
static uint32_t tcpv4_init_isn(struct in_addr *saddr,
struct in_addr *daddr,
uint16_t sport,
uint16_t dport)
{
struct {
uint8_t key[sizeof(unique_key)];
struct in_addr saddr;
struct in_addr daddr;
uint16_t sport;
uint16_t dport;
} buf = {
.saddr = *(struct in_addr *)saddr,
.daddr = *(struct in_addr *)daddr,
.sport = sport,
.dport = dport
};
uint8_t hash[16];
static bool once;
if (!once) {
sys_rand_get(unique_key, sizeof(unique_key));
once = true;
}
memcpy(buf.key, unique_key, sizeof(unique_key));
#if defined(CONFIG_NET_TCP_ISN_RFC6528)
mbedtls_md5((const unsigned char *)&buf, sizeof(buf), hash);
#endif
return seq_scale(UNALIGNED_GET((uint32_t *)&hash[0]));
}
static uint32_t tcp_init_isn(struct sockaddr *saddr, struct sockaddr *daddr)
{
if (IS_ENABLED(CONFIG_NET_TCP_ISN_RFC6528)) {
if (IS_ENABLED(CONFIG_NET_IPV6) &&
saddr->sa_family == AF_INET6) {
return tcpv6_init_isn(&net_sin6(saddr)->sin6_addr,
&net_sin6(daddr)->sin6_addr,
net_sin6(saddr)->sin6_port,
net_sin6(daddr)->sin6_port);
} else if (IS_ENABLED(CONFIG_NET_IPV4) &&
saddr->sa_family == AF_INET) {
return tcpv4_init_isn(&net_sin(saddr)->sin_addr,
&net_sin(daddr)->sin_addr,
net_sin(saddr)->sin_port,
net_sin(daddr)->sin_port);
}
}
return sys_rand32_get();
}
/* Create a new tcp connection, as a part of it, create and register
* net_context
*/
static struct tcp *tcp_conn_new(struct net_pkt *pkt)
{
struct tcp *conn = NULL;
struct net_context *context = NULL;
sa_family_t af = net_pkt_family(pkt);
struct sockaddr local_addr = { 0 };
int ret;
ret = net_context_get(af, SOCK_STREAM, IPPROTO_TCP, &context);
if (ret < 0) {
NET_ERR("net_context_get(): %d", ret);
goto err;
}
conn = context->tcp;
conn->iface = pkt->iface;
tcp_derive_rto(conn);
net_context_set_family(conn->context, net_pkt_family(pkt));
if (tcp_endpoint_set(&conn->dst, pkt, TCP_EP_SRC) < 0) {
net_context_put(context);
conn = NULL;
goto err;
}
if (tcp_endpoint_set(&conn->src, pkt, TCP_EP_DST) < 0) {
net_context_put(context);
conn = NULL;
goto err;
}
NET_DBG("conn: src: %s, dst: %s",
net_sprint_addr(conn->src.sa.sa_family,
(const void *)&conn->src.sin.sin_addr),
net_sprint_addr(conn->dst.sa.sa_family,
(const void *)&conn->dst.sin.sin_addr));
memcpy(&context->remote, &conn->dst, sizeof(context->remote));
context->flags |= NET_CONTEXT_REMOTE_ADDR_SET;
net_sin_ptr(&context->local)->sin_family = af;
local_addr.sa_family = net_context_get_family(context);
if (IS_ENABLED(CONFIG_NET_IPV6) &&
net_context_get_family(context) == AF_INET6) {
net_ipaddr_copy(&net_sin6(&local_addr)->sin6_addr,
&conn->src.sin6.sin6_addr);
} else if (IS_ENABLED(CONFIG_NET_IPV4) &&
net_context_get_family(context) == AF_INET) {
net_ipaddr_copy(&net_sin(&local_addr)->sin_addr,
&conn->src.sin.sin_addr);
}
ret = net_context_bind(context, &local_addr, sizeof(local_addr));
if (ret < 0) {
NET_DBG("Cannot bind accepted context, connection reset");
net_context_put(context);
conn = NULL;
goto err;
}
if (!(IS_ENABLED(CONFIG_NET_TEST_PROTOCOL) ||
IS_ENABLED(CONFIG_NET_TEST))) {
conn->seq = tcp_init_isn(&local_addr, &context->remote);
}
NET_DBG("context: local: %s, remote: %s",
net_sprint_addr(local_addr.sa_family,
(const void *)&net_sin(&local_addr)->sin_addr),
net_sprint_addr(context->remote.sa_family,
(const void *)&net_sin(&context->remote)->sin_addr));
ret = net_conn_register(IPPROTO_TCP, af,
&context->remote, &local_addr,
ntohs(conn->dst.sin.sin_port),/* local port */
ntohs(conn->src.sin.sin_port),/* remote port */
context, tcp_recv, context,
&context->conn_handler);
if (ret < 0) {
NET_ERR("net_conn_register(): %d", ret);
net_context_put(context);
conn = NULL;
goto err;
}
err:
if (!conn) {
net_stats_update_tcp_seg_conndrop(net_pkt_iface(pkt));
}
return conn;
}
static bool tcp_validate_seq(struct tcp *conn, struct tcphdr *hdr)
{
return (net_tcp_seq_cmp(th_seq(hdr), conn->ack) >= 0) &&
(net_tcp_seq_cmp(th_seq(hdr), conn->ack + conn->recv_win) < 0);
}
static bool check_seq_list(struct net_buf *buf)
{
struct net_buf *last = NULL;
struct net_buf *tmp = buf;
uint32_t seq;
uint32_t next_seq = 0;
bool result = true;
while (tmp) {
seq = tcp_get_seq(tmp);
NET_DBG("buf %p seq %u len %d", tmp, seq, tmp->len);
if (last != NULL) {
if (next_seq != seq) {
result = false;
}
}
next_seq = seq + tmp->len;
last = tmp;
tmp = tmp->frags;
}
return result;
}
static void tcp_queue_recv_data(struct tcp *conn, struct net_pkt *pkt,
size_t len, uint32_t seq)
{
uint32_t seq_start = seq;
bool inserted = false;
struct net_buf *tmp;
NET_DBG("conn: %p len %zd seq %u ack %u", conn, len, seq, conn->ack);
tmp = pkt->buffer;
tcp_set_seq(tmp, seq);
seq += tmp->len;
tmp = tmp->frags;
while (tmp) {
tcp_set_seq(tmp, seq);
seq += tmp->len;
tmp = tmp->frags;
}
if (IS_ENABLED(CONFIG_NET_TCP_LOG_LEVEL_DBG)) {
NET_DBG("Queuing data: conn %p", conn);
}
if (!net_pkt_is_empty(conn->queue_recv_data)) {
/* Place the data to correct place in the list. If the data
* would not be sequential, then drop this packet.
*
* Only work with subtractions between sequence numbers in uint32_t format
* to proper handle cases that are around the wrapping point.
*/
/* Some potentential cases:
* Note: MI = MAX_INT
* Packet | Queued| End off1 | Start off| End off2 | Required handling
* Seq|Len|Seq|Len| | | |
* 3 | 3 | 6 | 4 | 3+3-6= 0 | NA | NA | Prepend
* 3 | 4 | 6 | 4 | 3+4-6 = 1 | NA | NA | Prepend, pull from buffer
* 3 | 7 | 6 | 4 | 3+7-6 = 4 | 6-3=3 | 6+4-3=7 | Drop queued data
* 3 | 8 | 6 | 4 | 3+8-6 = 5 | 6-3=3 | 6+4-3=7 | Drop queued data
* 6 | 5 | 6 | 4 | 6+5-6 = 5 | 6-6=0 | 6+4-6=4 | Drop queued data
* 6 | 4 | 6 | 4 | 6+4-6 = 4 | 6-6=0 | 6+4-6=4 | Drop queued data / packet
* 7 | 2 | 6 | 4 | 7+2-6 = 3 | 6-7=MI | 6+4-7=3 | Drop packet
* 10 | 2 | 6 | 4 | 10+2-6= 6 | 6-10=MI-3| 6+4-10=0 | Append
* 7 | 4 | 6 | 4 | 7+4-6 = 5 | 6-7 =MI | 6+4-7 =3 | Append, pull from packet
* 11 | 2 | 6 | 4 | 11+2-6= 7 | 6-11=MI-6| 6+4-11=MI-1 | Drop incoming packet
* 2 | 3 | 6 | 4 | 2+3-6= MI | 6-2=4 | 6+4-2=8 | Drop incoming packet
*/
uint32_t pending_seq;
uint32_t start_offset;
uint32_t end_offset;
size_t pending_len;
pending_seq = tcp_get_seq(conn->queue_recv_data->buffer);
end_offset = seq - pending_seq;
pending_len = net_pkt_get_len(conn->queue_recv_data);
if (end_offset < pending_len) {
if (end_offset < len) {
if (end_offset) {
net_pkt_remove_tail(pkt, end_offset);
}
/* Put new data before the pending data */
net_buf_frag_add(pkt->buffer,
conn->queue_recv_data->buffer);
NET_DBG("Adding at before queue, end_offset %i, pending_len %zu",
end_offset, pending_len);
conn->queue_recv_data->buffer = pkt->buffer;
inserted = true;
}
} else {
struct net_buf *last;
last = net_buf_frag_last(conn->queue_recv_data->buffer);
pending_seq = tcp_get_seq(last);
start_offset = pending_seq - seq_start;
/* Compute the offset w.r.t. the start point of the new packet */
end_offset = (pending_seq + last->len) - seq_start;
/* Check if queue start with within the within the new packet */
if ((start_offset < len) && (end_offset <= len)) {
/* The queued data is irrelevant since the new packet overlaps the
* new packet, take the new packet as contents
*/
net_buf_unref(conn->queue_recv_data->buffer);
conn->queue_recv_data->buffer = pkt->buffer;
inserted = true;
} else {
if (end_offset < len) {
if (end_offset) {
net_pkt_remove_tail(conn->queue_recv_data,
end_offset);
}
/* Put new data after pending data */
NET_DBG("Adding at end of queue, start %i, end %i, len %zu",
start_offset, end_offset, len);
net_buf_frag_add(conn->queue_recv_data->buffer,
pkt->buffer);
inserted = true;
}
}
}
if (inserted) {
NET_DBG("All pending data: conn %p", conn);
if (check_seq_list(conn->queue_recv_data->buffer) == false) {
NET_ERR("Incorrect order in out of order sequence for conn %p",
conn);
/* error in sequence list, drop it */
net_buf_unref(conn->queue_recv_data->buffer);
conn->queue_recv_data->buffer = NULL;
}
} else {
NET_DBG("Cannot add new data to queue");
}
} else {
net_pkt_append_buffer(conn->queue_recv_data, pkt->buffer);
inserted = true;
}
if (inserted) {
/* We need to keep the received data but free the pkt */
pkt->buffer = NULL;
if (!k_work_delayable_is_pending(&conn->recv_queue_timer)) {
k_work_reschedule_for_queue(
&tcp_work_q, &conn->recv_queue_timer,
K_MSEC(CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT));
}
}
}
static enum net_verdict tcp_data_received(struct tcp *conn, struct net_pkt *pkt,
size_t *len)
{
enum net_verdict ret;
if (*len == 0) {
return NET_DROP;
}
ret = tcp_data_get(conn, pkt, len);
net_stats_update_tcp_seg_recv(conn->iface);
conn_ack(conn, *len);
/* Delay ACK response in case of small window or missing PSH,
* as described in RFC 813.
*/
if (tcp_short_window(conn)) {
k_work_schedule_for_queue(&tcp_work_q, &conn->ack_timer,
ACK_DELAY);
} else {
k_work_cancel_delayable(&conn->ack_timer);
tcp_out(conn, ACK);
}
return ret;
}
static void tcp_out_of_order_data(struct tcp *conn, struct net_pkt *pkt,
size_t data_len, uint32_t seq)
{
size_t headers_len;
if (data_len == 0) {
return;
}
headers_len = net_pkt_get_len(pkt) - data_len;
/* Get rid of protocol headers from the data */
if (tcp_pkt_pull(pkt, headers_len) < 0) {
return;
}
/* We received out-of-order data. Try to queue it.
*/
tcp_queue_recv_data(conn, pkt, data_len, seq);
}
static void tcp_check_sock_options(struct tcp *conn)
{
int sndbuf_opt = 0;
int rcvbuf_opt = 0;
if (IS_ENABLED(CONFIG_NET_CONTEXT_SNDBUF)) {
(void)net_context_get_option(conn->context, NET_OPT_SNDBUF,
&sndbuf_opt, NULL);
}
if (IS_ENABLED(CONFIG_NET_CONTEXT_RCVBUF)) {
(void)net_context_get_option(conn->context, NET_OPT_RCVBUF,
&rcvbuf_opt, NULL);
}
if (sndbuf_opt > 0 && sndbuf_opt != conn->send_win_max) {
k_mutex_lock(&conn->lock, K_FOREVER);
conn->send_win_max = sndbuf_opt;
if (conn->send_win > conn->send_win_max) {
conn->send_win = conn->send_win_max;
}
k_mutex_unlock(&conn->lock);
}
if (rcvbuf_opt > 0 && rcvbuf_opt != conn->recv_win_max) {
int diff;
k_mutex_lock(&conn->lock, K_FOREVER);
diff = rcvbuf_opt - conn->recv_win_max;
conn->recv_win_max = rcvbuf_opt;
tcp_update_recv_wnd(conn, diff);
k_mutex_unlock(&conn->lock);
}
}
/* TCP state machine, everything happens here */
static enum net_verdict tcp_in(struct tcp *conn, struct net_pkt *pkt)
{
struct tcphdr *th = pkt ? th_get(pkt) : NULL;
uint8_t next = 0, fl = 0;
bool do_close = false;
bool connection_ok = false;
size_t tcp_options_len = th ? (th_off(th) - 5) * 4 : 0;
struct net_conn *conn_handler = NULL;
struct net_pkt *recv_pkt;
void *recv_user_data;
struct k_fifo *recv_data_fifo;
size_t len;
int ret;
int close_status = 0;
enum net_verdict verdict = NET_DROP;
if (th) {
/* Currently we ignore ECN and CWR flags */
fl = th_flags(th) & ~(ECN | CWR);
}
if (conn->state != TCP_SYN_SENT) {
tcp_check_sock_options(conn);
}
k_mutex_lock(&conn->lock, K_FOREVER);
NET_DBG("%s", tcp_conn_state(conn, pkt));
if (th && th_off(th) < 5) {
tcp_out(conn, RST);
do_close = true;
close_status = -ECONNRESET;
goto next_state;
}
if (FL(&fl, &, RST)) {
/* We only accept RST packet that has valid seq field. */
if (!tcp_validate_seq(conn, th)) {
net_stats_update_tcp_seg_rsterr(net_pkt_iface(pkt));
k_mutex_unlock(&conn->lock);
return NET_DROP;
}
/* Valid RST received. */
verdict = NET_OK;
net_stats_update_tcp_seg_rst(net_pkt_iface(pkt));
do_close = true;
close_status = -ECONNRESET;
goto next_state;
}
if (tcp_options_len && !tcp_options_check(&conn->recv_options, pkt,
tcp_options_len)) {
NET_DBG("DROP: Invalid TCP option list");
tcp_out(conn, RST);
do_close = true;
close_status = -ECONNRESET;
goto next_state;
}
if (th && (conn->state != TCP_LISTEN) && (conn->state != TCP_SYN_SENT) &&
tcp_validate_seq(conn, th) && FL(&fl, &, SYN)) {
/* According to RFC 793, ch 3.9 Event Processing, receiving SYN
* once the connection has been established is an error
* condition, reset should be sent and connection closed.
*/
NET_DBG("conn: %p, SYN received in %s state, dropping connection",
conn, tcp_state_to_str(conn->state, false));
net_stats_update_tcp_seg_drop(conn->iface);
tcp_out(conn, RST);
do_close = true;
close_status = -ECONNRESET;
goto next_state;
}
if (th) {
conn->send_win = ntohs(th_win(th));
if (conn->send_win > conn->send_win_max) {
NET_DBG("Lowering send window from %u to %u",
conn->send_win, conn->send_win_max);
conn->send_win = conn->send_win_max;
}
if (conn->send_win == 0) {
if (!k_work_delayable_is_pending(&conn->persist_timer)) {
conn->zwp_retries = 0;
(void)k_work_reschedule_for_queue(
&tcp_work_q, &conn->persist_timer,
K_MSEC(TCP_RTO_MS));
}
} else {
(void)k_work_cancel_delayable(&conn->persist_timer);
}
if (tcp_window_full(conn)) {
(void)k_sem_take(&conn->tx_sem, K_NO_WAIT);
} else {
k_sem_give(&conn->tx_sem);
}
}
next_state:
len = pkt ? tcp_data_len(pkt) : 0;
switch (conn->state) {
case TCP_LISTEN:
if (FL(&fl, ==, SYN)) {
/* Make sure our MSS is also sent in the ACK */
conn->send_options.mss_found = true;
conn_ack(conn, th_seq(th) + 1); /* capture peer's isn */
tcp_out(conn, SYN | ACK);
conn->send_options.mss_found = false;
conn_seq(conn, + 1);
next = TCP_SYN_RECEIVED;
/* Close the connection if we do not receive ACK on time.
*/
k_work_reschedule_for_queue(&tcp_work_q,
&conn->establish_timer,
ACK_TIMEOUT);
verdict = NET_OK;
} else {
conn->send_options.mss_found = true;
tcp_out(conn, SYN);
conn->send_options.mss_found = false;
conn_seq(conn, + 1);
next = TCP_SYN_SENT;
}
break;
case TCP_SYN_RECEIVED:
if (FL(&fl, &, ACK, th_ack(th) == conn->seq &&
th_seq(th) == conn->ack)) {
k_work_cancel_delayable(&conn->establish_timer);
tcp_send_timer_cancel(conn);
next = TCP_ESTABLISHED;
tcp_conn_ref(conn);
net_context_set_state(conn->context,
NET_CONTEXT_CONNECTED);
if (conn->accepted_conn) {
if (conn->accepted_conn->accept_cb) {
conn->accepted_conn->accept_cb(
conn->context,
&conn->accepted_conn->context->remote,
sizeof(struct sockaddr), 0,
conn->accepted_conn->context);
}
/* Make sure the accept_cb is only called once.
*/
conn->accepted_conn = NULL;
}
if (len) {
verdict = tcp_data_get(conn, pkt, &len);
if (verdict == NET_OK) {
/* net_pkt owned by the recv fifo now */
pkt = NULL;
}
conn_ack(conn, + len);
tcp_out(conn, ACK);
} else {
verdict = NET_OK;
}
}
break;
case TCP_SYN_SENT:
/* if we are in SYN SENT and receive only a SYN without an
* ACK , shouldn't we go to SYN RECEIVED state? See Figure
* 6 of RFC 793
*/
if (FL(&fl, &, SYN | ACK, th && th_ack(th) == conn->seq)) {
tcp_send_timer_cancel(conn);
conn_ack(conn, th_seq(th) + 1);
if (len) {
verdict = tcp_data_get(conn, pkt, &len);
if (verdict == NET_OK) {
/* net_pkt owned by the recv fifo now */
pkt = NULL;
}
conn_ack(conn, + len);
} else {
verdict = NET_OK;
}
next = TCP_ESTABLISHED;
tcp_conn_ref(conn);
net_context_set_state(conn->context,
NET_CONTEXT_CONNECTED);
tcp_out(conn, ACK);
/* The connection semaphore is released *after*
* we have changed the connection state. This way
* the application can send data and it is queued
* properly even if this thread is running in lower
* priority.
*/
connection_ok = true;
}
break;
case TCP_ESTABLISHED:
/* full-close */
if (th && FL(&fl, ==, (FIN | ACK), th_seq(th) == conn->ack)) {
if (net_tcp_seq_cmp(th_ack(th), conn->seq) > 0) {
uint32_t len_acked = th_ack(th) - conn->seq;
conn_seq(conn, + len_acked);
}
conn_ack(conn, + 1);
tcp_out(conn, FIN | ACK);
next = TCP_LAST_ACK;
verdict = NET_OK;
break;
} else if (th && FL(&fl, ==, FIN, th_seq(th) == conn->ack)) {
conn_ack(conn, + 1);
tcp_out(conn, ACK);
next = TCP_CLOSE_WAIT;
verdict = NET_OK;
break;
} else if (th && FL(&fl, ==, (FIN | ACK | PSH),
th_seq(th) == conn->ack)) {
if (len) {
verdict = tcp_data_get(conn, pkt, &len);
if (verdict == NET_OK) {
/* net_pkt owned by the recv fifo now */
pkt = NULL;
}
} else {
verdict = NET_OK;
}
conn_ack(conn, + len + 1);
tcp_out(conn, FIN | ACK);
next = TCP_LAST_ACK;
break;
}
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
if (th && (net_tcp_seq_cmp(th_ack(th), conn->seq) == 0)) {
/* Only if there is pending data, increment the duplicate ack count */
if (conn->send_data_total > 0) {
/* There could be also payload, only without payload account them */
if (len == 0) {
/* Increment the duplicate acc counter,
* but maximize the value
*/
conn->dup_ack_cnt = MIN(conn->dup_ack_cnt + 1,
DUPLICATE_ACK_RETRANSMIT_TRHESHOLD + 1);
}
} else {
conn->dup_ack_cnt = 0;
}
/* Only do fast retransmit when not already in a resend state */
if ((conn->data_mode == TCP_DATA_MODE_SEND) &&
(conn->dup_ack_cnt == DUPLICATE_ACK_RETRANSMIT_TRHESHOLD)) {
/* Apply a fast retransmit */
int temp_unacked_len = conn->unacked_len;
conn->unacked_len = 0;
(void)tcp_send_data(conn);
/* Restore the current transmission */
conn->unacked_len = temp_unacked_len;
}
}
#endif
if (th && (net_tcp_seq_cmp(th_ack(th), conn->seq) > 0)) {
uint32_t len_acked = th_ack(th) - conn->seq;
NET_DBG("conn: %p len_acked=%u", conn, len_acked);
if ((conn->send_data_total < len_acked) ||
(tcp_pkt_pull(conn->send_data,
len_acked) < 0)) {
NET_ERR("conn: %p, Invalid len_acked=%u "
"(total=%zu)", conn, len_acked,
conn->send_data_total);
net_stats_update_tcp_seg_drop(conn->iface);
tcp_out(conn, RST);
do_close = true;
close_status = -ECONNRESET;
break;
}
#ifdef CONFIG_NET_TCP_FAST_RETRANSMIT
/* New segment, reset duplicate ack counter */
conn->dup_ack_cnt = 0;
#endif
conn->send_data_total -= len_acked;
if (conn->unacked_len < len_acked) {
conn->unacked_len = 0;
} else {
conn->unacked_len -= len_acked;
}
if (!tcp_window_full(conn)) {
k_sem_give(&conn->tx_sem);
}
conn_seq(conn, + len_acked);
net_stats_update_tcp_seg_recv(conn->iface);
conn_send_data_dump(conn);
if (!k_work_delayable_remaining_get(
&conn->send_data_timer)) {
NET_DBG("conn: %p, Missing a subscription "
"of the send_data queue timer", conn);
break;
}
conn->send_data_retries = 0;
k_work_cancel_delayable(&conn->send_data_timer);
if (conn->data_mode == TCP_DATA_MODE_RESEND) {
conn->unacked_len = 0;
tcp_derive_rto(conn);
}
conn->data_mode = TCP_DATA_MODE_SEND;
/* We are closing the connection, send a FIN to peer */
if (conn->in_close && conn->send_data_total == 0) {
tcp_send_timer_cancel(conn);
next = TCP_FIN_WAIT_1;
tcp_out(conn, FIN | ACK);
conn_seq(conn, + 1);
verdict = NET_OK;
break;
}
ret = tcp_send_queued_data(conn);
if (ret < 0 && ret != -ENOBUFS) {
tcp_out(conn, RST);
do_close = true;
close_status = ret;
verdict = NET_OK;
break;
}
if (tcp_window_full(conn)) {
(void)k_sem_take(&conn->tx_sem, K_NO_WAIT);
}
}
if (th) {
if (th_seq(th) == conn->ack) {
if (len > 0) {
verdict = tcp_data_received(conn, pkt, &len);
if (verdict == NET_OK) {
/* net_pkt owned by the recv fifo now */
pkt = NULL;
}
} else {
/* ACK, no data */
verdict = NET_OK;
}
} else if (net_tcp_seq_greater(conn->ack, th_seq(th))) {
/* This should handle the acknowledgements of keep alive
* packets and retransmitted data.
* RISK:
* There is a tiny risk of creating a ACK loop this way when
* both ends of the connection are out of order due to packet
* loss is a simulatanious bidirectional data flow.
*/
tcp_out(conn, ACK); /* peer has resent */
net_stats_update_tcp_seg_ackerr(conn->iface);
verdict = NET_OK;
} else if (CONFIG_NET_TCP_RECV_QUEUE_TIMEOUT) {
tcp_out_of_order_data(conn, pkt, len,
th_seq(th));
/* Send out a duplicated ACK */
if ((len > 0) || FL(&fl, &, FIN)) {
tcp_out(conn, ACK);
}
verdict = NET_OK;
}
}
break;
case TCP_CLOSE_WAIT:
tcp_out(conn, FIN);
next = TCP_LAST_ACK;
break;
case TCP_LAST_ACK:
if (th && FL(&fl, ==, ACK, th_seq(th) == conn->ack)) {
tcp_send_timer_cancel(conn);
do_close = true;
verdict = NET_OK;
close_status = 0;
}
break;
case TCP_CLOSED:
break;
case TCP_FIN_WAIT_1:
if (th) {
/* Acknowledge but drop any new data */
if (len > 0) {
int32_t new_len = len - net_tcp_seq_cmp(conn->ack, th_seq(th));
/* Cases:
* - Data already received earlier: len > 0 , new_len <= 0
* - Partially new data len > 0, new_len > 0
* - Out of order data len > 0, new_len > 0, ignore the data in
* between
*/
if (new_len > 0) {
conn_ack(conn, + new_len);
}
}
/*
* Only if our FIN flag has been acknowledged and all the data has been
* received, it can go to the TIME_WAIT state
*/
if (FL(&fl, ==, (FIN | ACK),
(th_ack(th) == conn->seq) && (th_seq(th) == conn->ack))) {
tcp_send_timer_cancel(conn);
conn_ack(conn, + 1);
tcp_out(conn, ACK);
next = TCP_TIME_WAIT;
NET_DBG("FIN acknowledged, going to TIME_WAIT_STATE");
verdict = NET_OK;
} else if (th &&
(FL(&fl, ==, FIN, th_seq(th) == conn->ack) ||
FL(&fl, ==, (FIN | ACK), th_seq(th) == conn->ack))) {
tcp_send_timer_cancel(conn);
conn_ack(conn, + 1);
NET_DBG("FIN not yet acknowleged, going to CLOSING state");
if (th_ack(th) != conn->seq) {
/* Not acknowledged the FIN flag yet, so resend */
tcp_out_ext(conn, (FIN | ACK), NULL, conn->seq - 1);
} else {
tcp_out(conn, ACK);
}
next = TCP_CLOSING;
verdict = NET_OK;
} else if (th && FL(&fl, ==, ACK, th_ack(th) == conn->seq)) {
tcp_send_timer_cancel(conn);
next = TCP_FIN_WAIT_2;
verdict = NET_OK;
NET_DBG("FIN acknowledged, going to FIN_WAIT_2 state seq %u, ack %u"
, conn->seq, conn->ack);
/* Acknowledge any received data */
if (len > 0) {
tcp_out(conn, ACK);
}
} else if (th) {
NET_DBG("Staying in FIN_WAIT_1 flags 0x%x state seq %u, ack %u",
fl, conn->seq, conn->ack);
if (len > 0) {
tcp_send_timer_cancel(conn);
/* Send out a duplicate ACK, with the pending FIN flag */
tcp_out(conn, FIN | ACK);
}
verdict = NET_OK;
}
}
break;
case TCP_FIN_WAIT_2:
/* Acknowledge but drop any data, but subtract any duplicate data */
if (th) {
if (len > 0) {
int32_t new_len = len - net_tcp_seq_cmp(conn->ack, th_seq(th));
/* Cases:
* - Data already received earlier: len > 0 , new_len <= 0
* - Partially new data len > 0, new_len > 0
* - Out of order data len > 0, new_len > 0, ignore the data in
* between
*/
if (new_len > 0) {
conn_ack(conn, + new_len);
}
}
if (FL(&fl, ==, FIN, th_seq(th) == conn->ack) ||
FL(&fl, ==, FIN | ACK, th_seq(th) == conn->ack) ||
FL(&fl, ==, FIN | PSH | ACK,
th_seq(th) == conn->ack)) {
/* Received FIN on FIN_WAIT_2, so cancel the timer */
k_work_cancel_delayable(&conn->fin_timer);
conn_ack(conn, + 1);
tcp_out(conn, ACK);
next = TCP_TIME_WAIT;
verdict = NET_OK;
} else if (len > 0) {
/* Send out a duplicate ACK */
tcp_out(conn, ACK);
verdict = NET_OK;
}
}
break;
case TCP_CLOSING:
if (th && FL(&fl, ==, ACK, th_seq(th) == conn->ack)) {
tcp_send_timer_cancel(conn);
next = TCP_TIME_WAIT;
verdict = NET_OK;
}
break;
case TCP_TIME_WAIT:
/* Acknowledge any FIN attempts, in case retransmission took
* place.
*/
if (th && (FL(&fl, ==, (FIN | ACK), th_seq(th) + 1 == conn->ack) ||
FL(&fl, ==, FIN, th_seq(th) + 1 == conn->ack))) {
tcp_out(conn, ACK);
verdict = NET_OK;
}
k_work_reschedule_for_queue(
&tcp_work_q, &conn->timewait_timer,
K_MSEC(CONFIG_NET_TCP_TIME_WAIT_DELAY));
break;
default:
NET_ASSERT(false, "%s is unimplemented",
tcp_state_to_str(conn->state, true));
}
if (pkt) {
if (verdict == NET_OK) {
net_pkt_unref(pkt);
}
pkt = NULL;
}
if (next) {
th = NULL;
conn_state(conn, next);
next = 0;
if (connection_ok) {
conn->in_connect = false;
if (conn->connect_cb) {
conn->connect_cb(conn->context, 0, conn->context->user_data);
/* Make sure the connect_cb is only called once. */
conn->connect_cb = NULL;
}
k_sem_give(&conn->connect_sem);
}
goto next_state;
}
/* If the conn->context is not set, then the connection was already
* closed.
*/
if (conn->context) {
conn_handler = (struct net_conn *)conn->context->conn_handler;
}
recv_user_data = conn->recv_user_data;
recv_data_fifo = &conn->recv_data;
k_mutex_unlock(&conn->lock);
/* Pass all the received data stored in recv fifo to the application.
* This is done like this so that we do not have any connection lock
* held.
*/
while (conn_handler && atomic_get(&conn->ref_count) > 0 &&
(recv_pkt = k_fifo_get(recv_data_fifo, K_NO_WAIT)) != NULL) {
if (net_context_packet_received(conn_handler, recv_pkt, NULL,
NULL, recv_user_data) ==
NET_DROP) {
/* Application is no longer there, unref the pkt */
tcp_pkt_unref(recv_pkt);
}
}
/* We must not try to unref the connection while having a connection
* lock because the unref will try to acquire net_context lock and the
* application might have that lock held already, and that might lead
* to a deadlock.
*/
if (do_close) {
tcp_conn_close(conn, close_status);
}
return verdict;
}
/* Active connection close: send FIN and go to FIN_WAIT_1 state */
int net_tcp_put(struct net_context *context)
{
struct tcp *conn = context->tcp;
if (!conn) {
return -ENOENT;
}
k_mutex_lock(&conn->lock, K_FOREVER);
NET_DBG("%s", conn ? tcp_conn_state(conn, NULL) : "");
NET_DBG("context %p %s", context,
({ const char *state = net_context_state(context);
state ? state : "<unknown>"; }));
if (conn && conn->state == TCP_ESTABLISHED) {
/* Send all remaining data if possible. */
if (conn->send_data_total > 0) {
NET_DBG("conn %p pending %zu bytes", conn,
conn->send_data_total);
conn->in_close = true;
/* How long to wait until all the data has been sent?
*/
k_work_reschedule_for_queue(&tcp_work_q,
&conn->send_data_timer,
K_MSEC(TCP_RTO_MS));
} else {
int ret;
NET_DBG("TCP connection in active close, not "
"disposing yet (waiting %dms)", tcp_fin_timeout_ms);
k_work_reschedule_for_queue(&tcp_work_q,
&conn->fin_timer,
FIN_TIMEOUT);
ret = tcp_out_ext(conn, FIN | ACK, NULL,
conn->seq + conn->unacked_len);
if (ret == 0) {
conn_seq(conn, + 1);
}
conn_state(conn, TCP_FIN_WAIT_1);
}
} else if (conn && conn->in_connect) {
conn->in_connect = false;
}
k_mutex_unlock(&conn->lock);
tcp_conn_unref(conn);
return 0;
}
int net_tcp_listen(struct net_context *context)
{
/* when created, tcp connections are in state TCP_LISTEN */
net_context_set_state(context, NET_CONTEXT_LISTENING);
return 0;
}
int net_tcp_update_recv_wnd(struct net_context *context, int32_t delta)
{
struct tcp *conn = context->tcp;
int ret;
if (!conn) {
NET_ERR("context->tcp == NULL");
return -EPROTOTYPE;
}
k_mutex_lock(&conn->lock, K_FOREVER);
ret = tcp_update_recv_wnd((struct tcp *)context->tcp, delta);
k_mutex_unlock(&conn->lock);
return ret;
}
/* net_context queues the outgoing data for the TCP connection */
int net_tcp_queue_data(struct net_context *context, struct net_pkt *pkt)
{
struct tcp *conn = context->tcp;
struct net_buf *orig_buf = NULL;
int ret = 0;
size_t len;
if (!conn || conn->state != TCP_ESTABLISHED) {
return -ENOTCONN;
}
k_mutex_lock(&conn->lock, K_FOREVER);
if (tcp_window_full(conn)) {
if (conn->send_win == 0) {
/* No point retransmiting if the current TX window size
* is 0.
*/
ret = -EAGAIN;
goto out;
}
/* Trigger resend if the timer is not active */
/* TODO: use k_work_delayable for send_data_timer so we don't
* have to directly access the internals of the legacy object.
*
* NOTE: It is not permitted to access any fields of k_work or
* k_work_delayable directly. This replacement does so, but
* only as a temporary workaround until the legacy
* k_delayed_work structure is replaced with k_work_delayable;
* at that point k_work_schedule() can be invoked to cause the
* work to be scheduled if it is not already scheduled.
*
* This solution diverges from the original, which would
* invoke the retransmit function directly here. Because that
* function is given a k_work pointer, again this cannot be
* done without accessing the internal data of the
* k_work_delayable structure.
*
* The original inline retransmission could be supported by
* refactoring the work_handler to delegate to a function that
* takes conn directly, rather than the work item in which
* conn is embedded, and calling that function directly here
* and in the work handler.
*/
(void)k_work_schedule_for_queue(&tcp_work_q,
&conn->send_data_timer,
K_NO_WAIT);
ret = -EAGAIN;
goto out;
}
len = net_pkt_get_len(pkt);
if (conn->send_data->buffer) {
orig_buf = net_buf_frag_last(conn->send_data->buffer);
}
net_pkt_append_buffer(conn->send_data, pkt->buffer);
conn->send_data_total += len;
NET_DBG("conn: %p Queued %zu bytes (total %zu)", conn, len,
conn->send_data_total);
pkt->buffer = NULL;
ret = tcp_send_queued_data(conn);
if (ret < 0 && ret != -ENOBUFS) {
tcp_conn_close(conn, ret);
goto out;
}
if ((ret == -ENOBUFS) &&
(conn->send_data_total < (conn->unacked_len + len))) {
/* Some of the data has been sent, we cannot remove the
* whole chunk, the remainder portion is already
* in the send_data and will be transmitted upon a
* received ack or the next send call
*
* Set the return code back to 0 to pretend we just
* transmitted the chunk
*/
ret = 0;
}
if (ret == -ENOBUFS) {
/* Restore the original data so that we do not resend the pkt
* data multiple times.
*/
conn->send_data_total -= len;
if (orig_buf) {
pkt->buffer = orig_buf->frags;
orig_buf->frags = NULL;
} else {
pkt->buffer = conn->send_data->buffer;
conn->send_data->buffer = NULL;
}
/* If we have out-of-bufs case, and the send_data buffer has
* become empty, till the retransmit timer, as there is no
* data to retransmit.
* The socket layer will catch this and resend data if needed.
* Only perform this when it is just the newly added packet,
* otherwise it can disrupt any pending transmission
*/
if (conn->send_data_total == 0) {
NET_DBG("No bufs, cancelling retransmit timer");
k_work_cancel_delayable(&conn->send_data_timer);
}
} else {
if (tcp_window_full(conn)) {
(void)k_sem_take(&conn->tx_sem, K_NO_WAIT);
}
/* We should not free the pkt if there was an error. It will be
* freed in net_context.c:context_sendto()
*/
tcp_pkt_unref(pkt);
}
out:
k_mutex_unlock(&conn->lock);
return ret;
}
/* net context is about to send out queued data - inform caller only */
int net_tcp_send_data(struct net_context *context, net_context_send_cb_t cb,
void *user_data)
{
if (cb) {
cb(context, 0, user_data);
}
return 0;
}
/* When connect() is called on a TCP socket, register the socket for incoming
* traffic with net context and give the TCP packet receiving function, which
* in turn will call tcp_in() to deliver the TCP packet to the stack
*/
int net_tcp_connect(struct net_context *context,
const struct sockaddr *remote_addr,
struct sockaddr *local_addr,
uint16_t remote_port, uint16_t local_port,
k_timeout_t timeout, net_context_connect_cb_t cb,
void *user_data)
{
struct tcp *conn;
int ret = 0;
NET_DBG("context: %p, local: %s, remote: %s", context,
net_sprint_addr(local_addr->sa_family,
(const void *)&net_sin(local_addr)->sin_addr),
net_sprint_addr(remote_addr->sa_family,
(const void *)&net_sin(remote_addr)->sin_addr));
conn = context->tcp;
conn->iface = net_context_get_iface(context);
tcp_derive_rto(conn);
switch (net_context_get_family(context)) {
const struct in_addr *ip4;
const struct in6_addr *ip6;
case AF_INET:
if (!IS_ENABLED(CONFIG_NET_IPV4)) {
ret = -EINVAL;
goto out;
}
memset(&conn->src, 0, sizeof(struct sockaddr_in));
memset(&conn->dst, 0, sizeof(struct sockaddr_in));
conn->src.sa.sa_family = AF_INET;
conn->dst.sa.sa_family = AF_INET;
conn->dst.sin.sin_port = remote_port;
conn->src.sin.sin_port = local_port;
/* we have to select the source address here as
* net_context_create_ipv4_new() is not called in the packet
* output chain
*/
ip4 = net_if_ipv4_select_src_addr(
net_context_get_iface(context),
&net_sin(remote_addr)->sin_addr);
conn->src.sin.sin_addr = *ip4;
net_ipaddr_copy(&conn->dst.sin.sin_addr,
&net_sin(remote_addr)->sin_addr);
break;
case AF_INET6:
if (!IS_ENABLED(CONFIG_NET_IPV6)) {
ret = -EINVAL;
goto out;
}
memset(&conn->src, 0, sizeof(struct sockaddr_in6));
memset(&conn->dst, 0, sizeof(struct sockaddr_in6));
conn->src.sin6.sin6_family = AF_INET6;
conn->dst.sin6.sin6_family = AF_INET6;
conn->dst.sin6.sin6_port = remote_port;
conn->src.sin6.sin6_port = local_port;
ip6 = net_if_ipv6_select_src_addr(
net_context_get_iface(context),
&net_sin6(remote_addr)->sin6_addr);
conn->src.sin6.sin6_addr = *ip6;
net_ipaddr_copy(&conn->dst.sin6.sin6_addr,
&net_sin6(remote_addr)->sin6_addr);
break;
default:
ret = -EPROTONOSUPPORT;
}
if (!(IS_ENABLED(CONFIG_NET_TEST_PROTOCOL) ||
IS_ENABLED(CONFIG_NET_TEST))) {
conn->seq = tcp_init_isn(&conn->src.sa, &conn->dst.sa);
}
NET_DBG("conn: %p src: %s, dst: %s", conn,
net_sprint_addr(conn->src.sa.sa_family,
(const void *)&conn->src.sin.sin_addr),
net_sprint_addr(conn->dst.sa.sa_family,
(const void *)&conn->dst.sin.sin_addr));
net_context_set_state(context, NET_CONTEXT_CONNECTING);
ret = net_conn_register(net_context_get_proto(context),
net_context_get_family(context),
remote_addr, local_addr,
ntohs(remote_port), ntohs(local_port),
context, tcp_recv, context,
&context->conn_handler);
if (ret < 0) {
goto out;
}
conn->connect_cb = cb;
context->user_data = user_data;
/* Input of a (nonexistent) packet with no flags set will cause
* a TCP connection to be established
*/
conn->in_connect = !IS_ENABLED(CONFIG_NET_TEST_PROTOCOL);
(void)tcp_in(conn, NULL);
if (!IS_ENABLED(CONFIG_NET_TEST_PROTOCOL)) {
if ((K_TIMEOUT_EQ(timeout, K_NO_WAIT)) &&
conn->state != TCP_ESTABLISHED) {
ret = -EINPROGRESS;
goto out;
} else if (k_sem_take(&conn->connect_sem, timeout) != 0 &&
conn->state != TCP_ESTABLISHED) {
if (conn->in_connect) {
conn->in_connect = false;
tcp_conn_close(conn, -ETIMEDOUT);
}
ret = -ETIMEDOUT;
goto out;
}
conn->in_connect = false;
}
out:
NET_DBG("conn: %p, ret=%d", conn, ret);
return ret;
}
int net_tcp_accept(struct net_context *context, net_tcp_accept_cb_t cb,
void *user_data)
{
struct tcp *conn = context->tcp;
struct sockaddr local_addr = { };
uint16_t local_port, remote_port;
if (!conn) {
return -EINVAL;
}
NET_DBG("context: %p, tcp: %p, cb: %p", context, conn, cb);
if (conn->state != TCP_LISTEN) {
return -EINVAL;
}
conn->accept_cb = cb;
local_addr.sa_family = net_context_get_family(context);
switch (local_addr.sa_family) {
struct sockaddr_in *in;
struct sockaddr_in6 *in6;
case AF_INET:
if (!IS_ENABLED(CONFIG_NET_IPV4)) {
return -EINVAL;
}
in = (struct sockaddr_in *)&local_addr;
if (net_sin_ptr(&context->local)->sin_addr) {
net_ipaddr_copy(&in->sin_addr,
net_sin_ptr(&context->local)->sin_addr);
}
in->sin_port =
net_sin((struct sockaddr *)&context->local)->sin_port;
local_port = ntohs(in->sin_port);
remote_port = ntohs(net_sin(&context->remote)->sin_port);
break;
case AF_INET6:
if (!IS_ENABLED(CONFIG_NET_IPV6)) {
return -EINVAL;
}
in6 = (struct sockaddr_in6 *)&local_addr;
if (net_sin6_ptr(&context->local)->sin6_addr) {
net_ipaddr_copy(&in6->sin6_addr,
net_sin6_ptr(&context->local)->sin6_addr);
}
in6->sin6_port =
net_sin6((struct sockaddr *)&context->local)->sin6_port;
local_port = ntohs(in6->sin6_port);
remote_port = ntohs(net_sin6(&context->remote)->sin6_port);
break;
default:
return -EINVAL;
}
context->user_data = user_data;
/* Remove the temporary connection handler and register
* a proper now as we have an established connection.
*/
net_conn_unregister(context->conn_handler);
return net_conn_register(net_context_get_proto(context),
local_addr.sa_family,
context->flags & NET_CONTEXT_REMOTE_ADDR_SET ?
&context->remote : NULL,
&local_addr,
remote_port, local_port,
context, tcp_recv, context,
&context->conn_handler);
}
int net_tcp_recv(struct net_context *context, net_context_recv_cb_t cb,
void *user_data)
{
struct tcp *conn = context->tcp;
NET_DBG("context: %p, cb: %p, user_data: %p", context, cb, user_data);
context->recv_cb = cb;
if (conn) {
conn->recv_user_data = user_data;
}
return 0;
}
int net_tcp_finalize(struct net_pkt *pkt)
{
NET_PKT_DATA_ACCESS_DEFINE(tcp_access, struct net_tcp_hdr);
struct net_tcp_hdr *tcp_hdr;
tcp_hdr = (struct net_tcp_hdr *)net_pkt_get_data(pkt, &tcp_access);
if (!tcp_hdr) {
return -ENOBUFS;
}
tcp_hdr->chksum = 0U;
if (net_if_need_calc_tx_checksum(net_pkt_iface(pkt))) {
tcp_hdr->chksum = net_calc_chksum_tcp(pkt);
}
return net_pkt_set_data(pkt, &tcp_access);
}
struct net_tcp_hdr *net_tcp_input(struct net_pkt *pkt,
struct net_pkt_data_access *tcp_access)
{
struct net_tcp_hdr *tcp_hdr;
if (IS_ENABLED(CONFIG_NET_TCP_CHECKSUM) &&
net_if_need_calc_rx_checksum(net_pkt_iface(pkt)) &&
net_calc_chksum_tcp(pkt) != 0U) {
NET_DBG("DROP: checksum mismatch");
goto drop;
}
tcp_hdr = (struct net_tcp_hdr *)net_pkt_get_data(pkt, tcp_access);
if (tcp_hdr && !net_pkt_set_data(pkt, tcp_access)) {
return tcp_hdr;
}
drop:
net_stats_update_tcp_seg_chkerr(net_pkt_iface(pkt));
return NULL;
}
#if defined(CONFIG_NET_TEST_PROTOCOL)
static enum net_verdict tcp_input(struct net_conn *net_conn,
struct net_pkt *pkt,
union net_ip_header *ip,
union net_proto_header *proto,
void *user_data)
{
struct tcphdr *th = th_get(pkt);
enum net_verdict verdict = NET_DROP;
if (th) {
struct tcp *conn = tcp_conn_search(pkt);
if (conn == NULL && SYN == th_flags(th)) {
struct net_context *context =
tcp_calloc(1, sizeof(struct net_context));
net_tcp_get(context);
net_context_set_family(context, net_pkt_family(pkt));
conn = context->tcp;
tcp_endpoint_set(&conn->dst, pkt, TCP_EP_SRC);
tcp_endpoint_set(&conn->src, pkt, TCP_EP_DST);
/* Make an extra reference, the sanity check suite
* will delete the connection explicitly
*/
tcp_conn_ref(conn);
}
if (conn) {
conn->iface = pkt->iface;
verdict = tcp_in(conn, pkt);
}
}
return verdict;
}
static size_t tp_tcp_recv_cb(struct tcp *conn, struct net_pkt *pkt)
{
ssize_t len = tcp_data_len(pkt);
struct net_pkt *up = tcp_pkt_clone(pkt);
NET_DBG("pkt: %p, len: %zu", pkt, net_pkt_get_len(pkt));
net_pkt_cursor_init(up);
net_pkt_set_overwrite(up, true);
net_pkt_pull(up, net_pkt_get_len(up) - len);
net_tcp_queue_data(conn->context, up);
return len;
}
static ssize_t tp_tcp_recv(int fd, void *buf, size_t len, int flags)
{
return 0;
}
static void tp_init(struct tcp *conn, struct tp *tp)
{
struct tp out = {
.msg = "",
.status = "",
.state = tcp_state_to_str(conn->state, true),
.seq = conn->seq,
.ack = conn->ack,
.rcv = "",
.data = "",
.op = "",
};
*tp = out;
}
static void tcp_to_json(struct tcp *conn, void *data, size_t *data_len)
{
struct tp tp;
tp_init(conn, &tp);
tp_encode(&tp, data, data_len);
}
enum net_verdict tp_input(struct net_conn *net_conn,
struct net_pkt *pkt,
union net_ip_header *ip_hdr,
union net_proto_header *proto,
void *user_data)
{
struct net_udp_hdr *uh = net_udp_get_hdr(pkt, NULL);
size_t data_len = ntohs(uh->len) - sizeof(*uh);
struct tcp *conn = tcp_conn_search(pkt);
size_t json_len = 0;
struct tp *tp;
struct tp_new *tp_new;
enum tp_type type;
bool responded = false;
static char buf[512];
enum net_verdict verdict = NET_DROP;
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) +
net_pkt_ip_opts_len(pkt) + sizeof(*uh));
net_pkt_read(pkt, buf, data_len);
buf[data_len] = '\0';
data_len += 1;
type = json_decode_msg(buf, data_len);
data_len = ntohs(uh->len) - sizeof(*uh);
net_pkt_cursor_init(pkt);
net_pkt_set_overwrite(pkt, true);
net_pkt_skip(pkt, net_pkt_ip_hdr_len(pkt) +
net_pkt_ip_opts_len(pkt) + sizeof(*uh));
net_pkt_read(pkt, buf, data_len);
buf[data_len] = '\0';
data_len += 1;
switch (type) {
case TP_CONFIG_REQUEST:
tp_new = json_to_tp_new(buf, data_len);
break;
default:
tp = json_to_tp(buf, data_len);
break;
}
switch (type) {
case TP_COMMAND:
if (is("CONNECT", tp->op)) {
tp_output(pkt->family, pkt->iface, buf, 1);
responded = true;
{
struct net_context *context = tcp_calloc(1,
sizeof(struct net_context));
net_tcp_get(context);
net_context_set_family(context,
net_pkt_family(pkt));
conn = context->tcp;
tcp_endpoint_set(&conn->dst, pkt, TCP_EP_SRC);
tcp_endpoint_set(&conn->src, pkt, TCP_EP_DST);
conn->iface = pkt->iface;
tcp_conn_ref(conn);
}
conn->seq = tp->seq;
verdict = tcp_in(conn, NULL);
}
if (is("CLOSE", tp->op)) {
tp_trace = false;
{
struct net_context *context;
conn = (void *)sys_slist_peek_head(&tcp_conns);
context = conn->context;
while (tcp_conn_close(conn, 0))
;
tcp_free(context);
}
tp_mem_stat();
tp_nbuf_stat();
tp_pkt_stat();
tp_seq_stat();
}
if (is("CLOSE2", tp->op)) {
struct tcp *conn =
(void *)sys_slist_peek_head(&tcp_conns);
net_tcp_put(conn->context);
}
if (is("RECV", tp->op)) {
#define HEXSTR_SIZE 64
char hexstr[HEXSTR_SIZE];
ssize_t len = tp_tcp_recv(0, buf, sizeof(buf), 0);
tp_init(conn, tp);
bin2hex(buf, len, hexstr, HEXSTR_SIZE);
tp->data = hexstr;
NET_DBG("%zd = tcp_recv(\"%s\")", len, tp->data);
json_len = sizeof(buf);
tp_encode(tp, buf, &json_len);
}
if (is("SEND", tp->op)) {
ssize_t len = tp_str_to_hex(buf, sizeof(buf), tp->data);
struct tcp *conn =
(void *)sys_slist_peek_head(&tcp_conns);
tp_output(pkt->family, pkt->iface, buf, 1);
responded = true;
NET_DBG("tcp_send(\"%s\")", tp->data);
{
struct net_pkt *data_pkt;
data_pkt = tcp_pkt_alloc(conn, len);
net_pkt_write(data_pkt, buf, len);
net_pkt_cursor_init(data_pkt);
net_tcp_queue_data(conn->context, data_pkt);
}
}
break;
case TP_CONFIG_REQUEST:
tp_new_find_and_apply(tp_new, "tcp_rto", &tcp_rto, TP_INT);
tp_new_find_and_apply(tp_new, "tcp_retries", &tcp_retries,
TP_INT);
tp_new_find_and_apply(tp_new, "tcp_window", &tcp_rx_window,
TP_INT);
tp_new_find_and_apply(tp_new, "tp_trace", &tp_trace, TP_BOOL);
break;
case TP_INTROSPECT_REQUEST:
json_len = sizeof(buf);
conn = (void *)sys_slist_peek_head(&tcp_conns);
tcp_to_json(conn, buf, &json_len);
break;
case TP_DEBUG_STOP: case TP_DEBUG_CONTINUE:
tp_state = tp->type;
break;
default:
NET_ASSERT(false, "Unimplemented tp command: %s", tp->msg);
}
if (json_len) {
tp_output(pkt->family, pkt->iface, buf, json_len);
} else if ((TP_CONFIG_REQUEST == type || TP_COMMAND == type)
&& responded == false) {
tp_output(pkt->family, pkt->iface, buf, 1);
}
return verdict;
}
static void test_cb_register(sa_family_t family, uint8_t proto, uint16_t remote_port,
uint16_t local_port, net_conn_cb_t cb)
{
struct net_conn_handle *conn_handle = NULL;
const struct sockaddr addr = { .sa_family = family, };
int ret = net_conn_register(proto,
family,
&addr, /* remote address */
&addr, /* local address */
local_port,
remote_port,
NULL,
cb,
NULL, /* user_data */
&conn_handle);
if (ret < 0) {
NET_ERR("net_conn_register(): %d", ret);
}
}
#endif /* CONFIG_NET_TEST_PROTOCOL */
void net_tcp_foreach(net_tcp_cb_t cb, void *user_data)
{
struct tcp *conn;
struct tcp *tmp;
k_mutex_lock(&tcp_lock, K_FOREVER);
SYS_SLIST_FOR_EACH_CONTAINER_SAFE(&tcp_conns, conn, tmp, next) {
if (atomic_get(&conn->ref_count) > 0) {
k_mutex_unlock(&tcp_lock);
cb(conn, user_data);
k_mutex_lock(&tcp_lock, K_FOREVER);
}
}
k_mutex_unlock(&tcp_lock);
}
uint16_t net_tcp_get_supported_mss(const struct tcp *conn)
{
sa_family_t family = net_context_get_family(conn->context);
if (family == AF_INET) {
#if defined(CONFIG_NET_IPV4)
struct net_if *iface = net_context_get_iface(conn->context);
int mss = 0;
if (iface && net_if_get_mtu(iface) >= NET_IPV4TCPH_LEN) {
/* Detect MSS based on interface MTU minus "TCP,IP
* header size"
*/
mss = net_if_get_mtu(iface) - NET_IPV4TCPH_LEN;
}
if (mss == 0) {
mss = NET_IPV4_MTU - NET_IPV4TCPH_LEN;
}
return mss;
#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(conn->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 == 0) {
mss = NET_IPV6_MTU - NET_IPV6TCPH_LEN;
}
return mss;
}
#endif /* CONFIG_NET_IPV6 */
return 0;
}
int net_tcp_set_option(struct net_context *context,
enum tcp_conn_option option,
const void *value, size_t len)
{
int ret = 0;
NET_ASSERT(context);
struct tcp *conn = context->tcp;
NET_ASSERT(conn);
k_mutex_lock(&conn->lock, K_FOREVER);
switch (option) {
case TCP_OPT_NODELAY:
ret = set_tcp_nodelay(conn, value, len);
break;
}
k_mutex_unlock(&conn->lock);
return ret;
}
int net_tcp_get_option(struct net_context *context,
enum tcp_conn_option option,
void *value, size_t *len)
{
int ret = 0;
NET_ASSERT(context);
struct tcp *conn = context->tcp;
NET_ASSERT(conn);
k_mutex_lock(&conn->lock, K_FOREVER);
switch (option) {
case TCP_OPT_NODELAY:
ret = get_tcp_nodelay(conn, value, len);
break;
}
k_mutex_unlock(&conn->lock);
return ret;
}
const char *net_tcp_state_str(enum tcp_state state)
{
return tcp_state_to_str(state, false);
}
struct k_sem *net_tcp_tx_sem_get(struct net_context *context)
{
struct tcp *conn = context->tcp;
return &conn->tx_sem;
}
struct k_sem *net_tcp_conn_sem_get(struct net_context *context)
{
struct tcp *conn = context->tcp;
return &conn->connect_sem;
}
void net_tcp_init(void)
{
int i;
int rto;
#if defined(CONFIG_NET_TEST_PROTOCOL)
/* Register inputs for TTCN-3 based TCP sanity check */
test_cb_register(AF_INET, IPPROTO_TCP, 4242, 4242, tcp_input);
test_cb_register(AF_INET6, IPPROTO_TCP, 4242, 4242, tcp_input);
test_cb_register(AF_INET, IPPROTO_UDP, 4242, 4242, tp_input);
test_cb_register(AF_INET6, IPPROTO_UDP, 4242, 4242, tp_input);
tcp_recv_cb = tp_tcp_recv_cb;
#endif
#if defined(CONFIG_NET_TC_THREAD_COOPERATIVE)
#define THREAD_PRIORITY K_PRIO_COOP(0)
#else
#define THREAD_PRIORITY K_PRIO_PREEMPT(0)
#endif
/* Use private workqueue in order not to block the system work queue.
*/
k_work_queue_start(&tcp_work_q, work_q_stack,
K_KERNEL_STACK_SIZEOF(work_q_stack), THREAD_PRIORITY,
NULL);
/* Compute the largest possible retransmission timeout */
tcp_fin_timeout_ms = 0;
rto = tcp_rto;
for (i = 0; i < tcp_retries; i++) {
tcp_fin_timeout_ms += rto;
rto += rto >> 1;
}
/* At the last timeout cicle */
tcp_fin_timeout_ms += tcp_rto;
/* When CONFIG_NET_TCP_RANDOMIZED_RTO is active in can be worse case 1.5 times larger */
if (IS_ENABLED(CONFIG_NET_TCP_RANDOMIZED_RTO)) {
tcp_fin_timeout_ms += tcp_fin_timeout_ms >> 1;
}
k_thread_name_set(&tcp_work_q.thread, "tcp_work");
NET_DBG("Workq started. Thread ID: %p", &tcp_work_q.thread);
}
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