1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** NetX Component */
17 /** */
18 /** Transmission Control Protocol (TCP) */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 #define NX_SOURCE_CODE
24
25
26 /* Include necessary system files. */
27
28 #include "nx_api.h"
29 #include "nx_tcp.h"
30
31
32 /**************************************************************************/
33 /* */
34 /* FUNCTION RELEASE */
35 /* */
36 /* _nx_tcp_packet_send_rst PORTABLE C */
37 /* 6.1 */
38 /* AUTHOR */
39 /* */
40 /* Yuxin Zhou, Microsoft Corporation */
41 /* */
42 /* DESCRIPTION */
43 /* */
44 /* This function sends a RST from the specified socket. */
45 /* */
46 /* INPUT */
47 /* */
48 /* socket_ptr Pointer to socket */
49 /* header_ptr Pointer to received header */
50 /* */
51 /* OUTPUT */
52 /* */
53 /* None */
54 /* */
55 /* CALLS */
56 /* */
57 /* _nx_tcp_packet_send_control Send TCP control packet */
58 /* */
59 /* CALLED BY */
60 /* */
61 /* _nx_tcp_socket_disconnect Disconnect processing */
62 /* _nx_tcp_socket_state_syn_received Socket SYN received processing*/
63 /* _nx_tcp_socket_state_syn_sent Socket SYN sent processing */
64 /* */
65 /* RELEASE HISTORY */
66 /* */
67 /* DATE NAME DESCRIPTION */
68 /* */
69 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
70 /* 09-30-2020 Yuxin Zhou Modified comment(s), */
71 /* resulting in version 6.1 */
72 /* */
73 /**************************************************************************/
_nx_tcp_packet_send_rst(NX_TCP_SOCKET * socket_ptr,NX_TCP_HEADER * header_ptr)74 VOID _nx_tcp_packet_send_rst(NX_TCP_SOCKET *socket_ptr, NX_TCP_HEADER *header_ptr)
75 {
76
77 /* Reset Generation, RFC793, Section3.4, Page37, the RST packet is set up based on if the incoming packet has the ACK bit set. */
78 /* If the incoming segment has an ACK field, the reset takes its sequence number from the ACK field of the segment,
79 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. */
80
81 /* Check for the ACK bit in the incoming TCP header. */
82 if (header_ptr -> nx_tcp_header_word_3 & NX_TCP_ACK_BIT)
83 {
84 _nx_tcp_packet_send_control(socket_ptr, NX_TCP_RST_BIT, header_ptr -> nx_tcp_acknowledgment_number,
85 0, 0, 0, NX_NULL);
86 }
87 else
88 {
89 _nx_tcp_packet_send_control(socket_ptr, (NX_TCP_RST_BIT | NX_TCP_ACK_BIT), 0,
90 header_ptr -> nx_tcp_sequence_number, 0, 0, NX_NULL);
91 }
92
93 #ifndef NX_DISABLE_TCP_INFO
94 /* Increment the resets sent count. */
95 socket_ptr -> nx_tcp_socket_ip_ptr -> nx_ip_tcp_resets_sent++;
96 #endif /* NX_DISABLE_TCP_INFO */
97 }
98
99
