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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Component */
/** */
/** Transmission Control Protocol (TCP) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_tcp.h"
#include "nx_ip.h"
#ifdef FEATURE_NX_IPV6
#include "nx_ipv6.h"
#endif /* FEATURE_NX_IPV6 */
#ifdef NX_IPSEC_ENABLE
#include "nx_ipsec.h"
#endif /* NX_IPSEC_ENABLE */
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_tcp_packet_send_syn PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function sends a SYN from the specified socket. */
/* */
/* INPUT */
/* */
/* socket_ptr Pointer to socket */
/* tx_sequence Transmit sequence number */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_tcp_packet_send_control Send TCP control packet */
/* _nx_packet_egress_sa_lookup IPsec process */
/* */
/* CALLED BY */
/* */
/* _nx_tcp_client_socket_connect Client connect processing */
/* _nx_tcp_periodic_processing Connection retry processing */
/* _nx_tcp_packet_process Server connect response */
/* processing */
/* _nx_tcp_server_socket_accept Server socket accept */
/* processing */
/* _nx_tcp_socket_state_syn_sent Socket SYN sent processing */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
/* 09-30-2020 Yuxin Zhou Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
VOID _nx_tcp_packet_send_syn(NX_TCP_SOCKET *socket_ptr, ULONG tx_sequence)
{
#ifdef NX_IPSEC_ENABLE
ULONG data_offset = 0;
NXD_ADDRESS src_addr;
UINT ret;
NX_IPSEC_SA *cur_sa_ptr = NX_NULL;
#endif /* NX_IPSEC_ENABLE */
ULONG option_word_1;
ULONG option_word_2;
#ifdef NX_ENABLE_TCP_WINDOW_SCALING
UINT include_window_scaling = NX_FALSE;
UINT scale_factor;
#endif /* NX_ENABLE_TCP_WINDOW_SCALING */
ULONG mss = 0;
#ifdef NX_IPSEC_ENABLE
#ifndef NX_DISABLE_IPV4
/* Look for egress SA first. */
if (socket_ptr -> nx_tcp_socket_connect_ip.nxd_ip_version == NX_IP_VERSION_V4)
{
src_addr.nxd_ip_version = NX_IP_VERSION_V4;
src_addr.nxd_ip_address.v4 = socket_ptr -> nx_tcp_socket_connect_interface -> nx_interface_ip_address;
}
#endif /* !NX_DISABLE_IPV4 */
#ifdef FEATURE_NX_IPV6
if (socket_ptr -> nx_tcp_socket_connect_ip.nxd_ip_version == NX_IP_VERSION_V6)
{
/* IPv6 case. */
src_addr.nxd_ip_version = NX_IP_VERSION_V6;
COPY_IPV6_ADDRESS(socket_ptr -> nx_tcp_socket_ipv6_addr -> nxd_ipv6_address, src_addr.nxd_ip_address.v6);
}
#endif /* FEATURE_NX_IPV6 */
/* Check for possible SA match. */
if (socket_ptr -> nx_tcp_socket_ip_ptr -> nx_ip_packet_egress_sa_lookup != NX_NULL) /* IPsec is enabled. */
{
/* If the SA has not been set. */
ret = socket_ptr -> nx_tcp_socket_ip_ptr -> nx_ip_packet_egress_sa_lookup(socket_ptr -> nx_tcp_socket_ip_ptr, /* IP ptr */
&src_addr, /* src_addr */
&socket_ptr -> nx_tcp_socket_connect_ip, /* dest_addr */
NX_PROTOCOL_TCP, /* protocol */
socket_ptr -> nx_tcp_socket_port, /* src_port */
socket_ptr -> nx_tcp_socket_connect_port, /* dest_port */
&data_offset, (VOID *)&cur_sa_ptr, 0);
if (ret == NX_IPSEC_TRAFFIC_PROTECT)
{
/* Save the SA to the socket. */
socket_ptr -> nx_tcp_socket_egress_sa = cur_sa_ptr;
socket_ptr -> nx_tcp_socket_egress_sa_data_offset = data_offset;
}
else if (ret == NX_IPSEC_TRAFFIC_DROP || ret == NX_IPSEC_TRAFFIC_PENDING_IKEV2)
{
return;
}
else
{
/* Zero out SA information. */
socket_ptr -> nx_tcp_socket_egress_sa = NX_NULL;
socket_ptr -> nx_tcp_socket_egress_sa_data_offset = 0;
}
}
else
{
socket_ptr -> nx_tcp_socket_egress_sa = NX_NULL;
}
#endif /* NX_IPSEC_ENABLE */
#ifndef NX_DISABLE_IPV4
/* Update the mss value based on IP version type. */
if (socket_ptr -> nx_tcp_socket_connect_ip.nxd_ip_version == NX_IP_VERSION_V4)
{
mss = (ULONG)((socket_ptr -> nx_tcp_socket_connect_interface -> nx_interface_ip_mtu_size - sizeof(NX_IPV4_HEADER)) - sizeof(NX_TCP_HEADER));
#ifdef NX_IPSEC_ENABLE
if (cur_sa_ptr != NX_NULL)
{
/* Update the mss value based on sa mode. */
if (cur_sa_ptr -> nx_ipsec_sa_protocol == NX_PROTOCOL_NEXT_HEADER_ENCAP_SECURITY)
{
/* Update the mss value. minus the ESP HEADER's pad length and IV size , */
mss = mss - sizeof(NX_IPSEC_ESP_HEADER) -
(cur_sa_ptr -> nx_ipsec_sa_encryption_method -> nx_crypto_block_size_in_bytes) -
((cur_sa_ptr -> nx_ipsec_sa_encryption_method -> nx_crypto_IV_size_in_bits) >> 3) -
((cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_ICV_size_in_bits) >> 3);
}
if (cur_sa_ptr -> nx_ipsec_sa_protocol == NX_PROTOCOL_NEXT_HEADER_AUTHENTICATION)
{
/* Update the mss value. minus the ESP HEADER's IV size and ICV size. */
mss = mss - sizeof(NX_IPSEC_AUTHENTICATION_HEADER) -
(cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_IV_size_in_bits >> 3) -
(cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_ICV_size_in_bits >> 3);
}
/* If the sa is tunnel mode, the mss value should minus the IPV4 header size . */
if (cur_sa_ptr -> nx_ipsec_sa_mode == NX_IPSEC_TUNNEL_MODE)
{
mss -= (sizeof(NX_IPV4_HEADER));
}
}
#endif /* NX_IPSEC_ENABLE */
}
#endif /* !NX_DISABLE_IPV4 */
#ifdef FEATURE_NX_IPV6
if (socket_ptr -> nx_tcp_socket_connect_ip.nxd_ip_version == NX_IP_VERSION_V6)
{
mss = (ULONG)((socket_ptr -> nx_tcp_socket_connect_interface -> nx_interface_ip_mtu_size - sizeof(NX_IPV6_HEADER)) - sizeof(NX_TCP_HEADER));
#ifdef NX_IPSEC_ENABLE
if (cur_sa_ptr != NX_NULL)
{
/* Update the mss value based on sa mode. */
if (cur_sa_ptr -> nx_ipsec_sa_protocol == NX_PROTOCOL_NEXT_HEADER_ENCAP_SECURITY)
{
/* Update the mss value. minus the ESP header's pad length and IV size , */
mss = mss - sizeof(NX_IPSEC_ESP_HEADER) -
(cur_sa_ptr -> nx_ipsec_sa_encryption_method -> nx_crypto_block_size_in_bytes) -
((cur_sa_ptr -> nx_ipsec_sa_encryption_method -> nx_crypto_IV_size_in_bits) >> 3) -
((cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_ICV_size_in_bits) >> 3);
}
if (cur_sa_ptr -> nx_ipsec_sa_protocol == NX_PROTOCOL_NEXT_HEADER_AUTHENTICATION)
{
/* Update the mss value. minus the ESP HEADER's IV size and ICV size. */
mss = mss - sizeof(NX_IPSEC_AUTHENTICATION_HEADER) -
(cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_IV_size_in_bits >> 3) -
(cur_sa_ptr -> nx_ipsec_sa_integrity_method -> nx_crypto_ICV_size_in_bits >> 3);
}
/* If the sa mode is tunnel mode,the mss value should minus the IPV6 header size . */
if (cur_sa_ptr -> nx_ipsec_sa_mode == NX_IPSEC_TUNNEL_MODE)
{
mss -= (sizeof(NX_IPV6_HEADER));
}
}
#endif /* NX_IPSEC_ENABLE */
}
#endif /* FEATURE_NX_IPV6 */
mss &= 0x0000FFFFUL;
if ((socket_ptr -> nx_tcp_socket_mss < mss) && socket_ptr -> nx_tcp_socket_mss)
{
/* Use the custom MSS. */
mss = socket_ptr -> nx_tcp_socket_mss;
}
if (socket_ptr -> nx_tcp_socket_state == NX_TCP_SYN_RECEIVED)
{
/* Update the connect MSS for TCP server socket. */
if (mss < socket_ptr -> nx_tcp_socket_peer_mss)
{
socket_ptr -> nx_tcp_socket_connect_mss = mss;
}
else
{
socket_ptr -> nx_tcp_socket_connect_mss = socket_ptr -> nx_tcp_socket_peer_mss;
}
/* Compute the SMSS * SMSS value, so later TCP module doesn't need to redo the multiplication. */
socket_ptr -> nx_tcp_socket_connect_mss2 =
socket_ptr -> nx_tcp_socket_connect_mss * socket_ptr -> nx_tcp_socket_connect_mss;
}
else
{
/* Set the MSS. */
socket_ptr -> nx_tcp_socket_connect_mss = mss;
}
/* Build the MSS option. */
option_word_1 = NX_TCP_MSS_OPTION | mss;
/* Set default option word2. */
option_word_2 = NX_TCP_OPTION_END;
#ifdef NX_ENABLE_TCP_WINDOW_SCALING
/* Include window scaling option if we initiates the SYN, or the peer supports Window Scaling. */
if (socket_ptr -> nx_tcp_socket_state == NX_TCP_SYN_SENT)
{
include_window_scaling = NX_TRUE;
}
else if (socket_ptr -> nx_tcp_snd_win_scale_value != 0xFF)
{
include_window_scaling = NX_TRUE;
}
if (include_window_scaling)
{
/* Sets the window scaling option. */
option_word_2 = NX_TCP_RWIN_OPTION;
/* Compute the window scaling factor */
for (scale_factor = 0; scale_factor < 15; scale_factor++)
{
if ((socket_ptr -> nx_tcp_socket_rx_window_current >> scale_factor) < 65536)
{
break;
}
}
/* Make sure window scale is limited to 14, per RFC 1323 pp.11. */
if (scale_factor == 15)
{
scale_factor = 14;
socket_ptr -> nx_tcp_socket_rx_window_default = (1 << 30) - 1;
socket_ptr -> nx_tcp_socket_rx_window_current = (1 << 30) - 1;
}
option_word_2 |= scale_factor << 8;
/* Update the socket with the scale factor. */
socket_ptr -> nx_tcp_rcv_win_scale_value = scale_factor;
}
#endif /* NX_ENABLE_TCP_WINDOW_SCALING */
/* Send SYN or SYN+ACK packet according to socket state. */
if (socket_ptr -> nx_tcp_socket_state == NX_TCP_SYN_SENT)
{
_nx_tcp_packet_send_control(socket_ptr, NX_TCP_SYN_BIT, tx_sequence,
0, option_word_1, option_word_2, NX_NULL);
}
else
{
_nx_tcp_packet_send_control(socket_ptr, (NX_TCP_SYN_BIT | NX_TCP_ACK_BIT), tx_sequence,
socket_ptr -> nx_tcp_socket_rx_sequence, option_word_1, option_word_2, NX_NULL);
}
/* Initialize recover sequence and previous cumulative acknowledgment. */
socket_ptr -> nx_tcp_socket_tx_sequence_recover = tx_sequence;
socket_ptr -> nx_tcp_socket_previous_highest_ack = tx_sequence;
}