1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** NetX Component */
16 /** */
17 /** Transmission Control Protocol (TCP) */
18 /** */
19 /**************************************************************************/
20 /**************************************************************************/
21
22 #define NX_SOURCE_CODE
23
24
25 /* Include necessary system files. */
26
27 #include "nx_api.h"
28 #include "nx_tcp.h"
29
30
31 /**************************************************************************/
32 /* */
33 /* FUNCTION RELEASE */
34 /* */
35 /* _nx_tcp_packet_send_rst PORTABLE C */
36 /* 6.1 */
37 /* AUTHOR */
38 /* */
39 /* Yuxin Zhou, Microsoft Corporation */
40 /* */
41 /* DESCRIPTION */
42 /* */
43 /* This function sends a RST from the specified socket. */
44 /* */
45 /* INPUT */
46 /* */
47 /* socket_ptr Pointer to socket */
48 /* header_ptr Pointer to received header */
49 /* */
50 /* OUTPUT */
51 /* */
52 /* None */
53 /* */
54 /* CALLS */
55 /* */
56 /* _nx_tcp_packet_send_control Send TCP control packet */
57 /* */
58 /* CALLED BY */
59 /* */
60 /* _nx_tcp_socket_disconnect Disconnect processing */
61 /* _nx_tcp_socket_state_syn_received Socket SYN received processing*/
62 /* _nx_tcp_socket_state_syn_sent Socket SYN sent processing */
63 /* */
64 /* RELEASE HISTORY */
65 /* */
66 /* DATE NAME DESCRIPTION */
67 /* */
68 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
69 /* 09-30-2020 Yuxin Zhou Modified comment(s), */
70 /* resulting in version 6.1 */
71 /* */
72 /**************************************************************************/
_nx_tcp_packet_send_rst(NX_TCP_SOCKET * socket_ptr,NX_TCP_HEADER * header_ptr)73 VOID _nx_tcp_packet_send_rst(NX_TCP_SOCKET *socket_ptr, NX_TCP_HEADER *header_ptr)
74 {
75
76 /* Reset Generation, RFC793, Section3.4, Page37, the RST packet is set up based on if the incoming packet has the ACK bit set. */
77 /* If the incoming segment has an ACK field, the reset takes its sequence number from the ACK field of the segment,
78 otherwise the reset has sequence number zero and the ACK field is set to the sum of the sequence number and segment length of the incoming segment. */
79
80 /* Check for the ACK bit in the incoming TCP header. */
81 if (header_ptr -> nx_tcp_header_word_3 & NX_TCP_ACK_BIT)
82 {
83 _nx_tcp_packet_send_control(socket_ptr, NX_TCP_RST_BIT, header_ptr -> nx_tcp_acknowledgment_number,
84 0, 0, 0, NX_NULL);
85 }
86 else
87 {
88 _nx_tcp_packet_send_control(socket_ptr, (NX_TCP_RST_BIT | NX_TCP_ACK_BIT), 0,
89 header_ptr -> nx_tcp_sequence_number, 0, 0, NX_NULL);
90 }
91
92 #ifndef NX_DISABLE_TCP_INFO
93 /* Increment the resets sent count. */
94 socket_ptr -> nx_tcp_socket_ip_ptr -> nx_ip_tcp_resets_sent++;
95 #endif /* NX_DISABLE_TCP_INFO */
96 }
97
98
