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 /** Packet Pool Management (Packet) */
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_packet.h"
29
30
31 /**************************************************************************/
32 /* */
33 /* FUNCTION RELEASE */
34 /* */
35 /* _nx_packet_data_adjust PORTABLE C */
36 /* 6.1 */
37 /* AUTHOR */
38 /* */
39 /* Yuxin Zhou, Microsoft Corporation */
40 /* */
41 /* DESCRIPTION */
42 /* */
43 /* This function adjusts the packet data to fill the specified header. */
44 /* */
45 /* INPUT */
46 /* */
47 /* packet_ptr Pointer to the source packet */
48 /* header_size The size of header */
49 /* */
50 /* OUTPUT */
51 /* */
52 /* status Completion status */
53 /* */
54 /* CALLS */
55 /* */
56 /* _nx_packet_allocate Allocate data packet */
57 /* _nx_packet_data_append Packet data append service */
58 /* _nx_packet_release Release data packet */
59 /* */
60 /* CALLED BY */
61 /* */
62 /* _nx_ip_forward_packet_process Forward IP packet */
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), and */
70 /* verified memcpy use cases, */
71 /* verified memmove use cases, */
72 /* resulting in version 6.1 */
73 /* */
74 /**************************************************************************/
_nx_packet_data_adjust(NX_PACKET * packet_ptr,ULONG header_size)75 UINT _nx_packet_data_adjust(NX_PACKET *packet_ptr, ULONG header_size)
76 {
77
78 ULONG available_size;
79 ULONG shift_size;
80 #ifndef NX_DISABLE_PACKET_CHAIN
81 UINT status;
82 ULONG append_size;
83 UCHAR *data_start;
84 NX_PACKET *work_ptr;
85 #endif /* !NX_DISABLE_PACKET_CHAIN */
86
87
88 /* Add debug information. */
89 NX_PACKET_DEBUG(__FILE__, __LINE__, packet_ptr);
90
91 /* The header must be filled in one packet. */
92 if (((ALIGN_TYPE)packet_ptr -> nx_packet_data_end - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) < header_size)
93 {
94 return(NX_UNDERFLOW);
95 }
96
97 /* 1. Check if there is enough space to add header. */
98 if (((ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) >= header_size)
99 {
100
101 /* Yes. Just return success. */
102 return(NX_SUCCESS);
103 }
104
105 /* Compute the total avilable size in this packet. */
106 available_size = (ULONG)(((ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) +
107 ((ALIGN_TYPE)packet_ptr -> nx_packet_data_end - (ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr));
108
109 /* 2. Would the header fit into the available space? */
110 if (available_size >= header_size)
111 {
112
113 /* Yes, adjust the data. */
114
115 /* Calculate the shift data size. */
116 shift_size = (ULONG)((ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr);
117
118 /* Move the data, */
119 memmove(packet_ptr -> nx_packet_data_start + header_size, packet_ptr -> nx_packet_prepend_ptr, shift_size); /* Use case of memmove is verified. */
120
121 /* Update the prepend and append pointer. */
122 packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_data_start + header_size;
123 packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_prepend_ptr + shift_size;
124 }
125 else
126 {
127
128 #ifndef NX_DISABLE_PACKET_CHAIN
129
130 /* 3. Current packet does not have enough space to fill the header.
131 Allocate a new packet to fill the overflowing data and chain the packet. */
132
133 /* Odd value of header_size is not supported now.
134 * In _nx_ip_checksum_compute(), nx_packet_append_ptr must not be odd value. */
135 if (header_size & 1)
136 {
137 return(NX_NOT_SUPPORTED);
138 }
139
140 /* Calculate the append data size. */
141 append_size = header_size - available_size;
142
143 /* Set the append data pointer. */
144 data_start = packet_ptr -> nx_packet_append_ptr - append_size;
145
146 /* Allocate a packet. */
147 status = _nx_packet_allocate(packet_ptr -> nx_packet_pool_owner, &work_ptr, 0, NX_NO_WAIT);
148
149 /* Check status. */
150 if (status)
151 {
152 return(status);
153 }
154
155 /* Firstly, append the overflowing data to the new packet.. */
156 memcpy(work_ptr -> nx_packet_prepend_ptr, data_start, append_size); /* Use case of memcpy is verified. lgtm[cpp/banned-api-usage-required-any] */
157 work_ptr -> nx_packet_append_ptr = (UCHAR *)((ALIGN_TYPE)work_ptr -> nx_packet_prepend_ptr + append_size);
158
159 /* Secondly, calculate the shift data size. */
160 shift_size = (ULONG)(((ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr) - append_size);
161
162 /* Move the data. */
163 memmove(packet_ptr -> nx_packet_data_start + header_size, packet_ptr -> nx_packet_prepend_ptr, shift_size); /* Use case of memmove is verified. */
164
165 /* Update the prepend and append pointer. */
166 packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_data_start + header_size;
167 packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_prepend_ptr + shift_size;
168
169 /* At this point, all the necessary packets have been allocated.
170 We need to link this new packet to the next of the supplied packet. */
171 work_ptr -> nx_packet_next = packet_ptr -> nx_packet_next;
172 packet_ptr -> nx_packet_next = work_ptr;
173
174 /* Update the last packet pointer. */
175 if (packet_ptr -> nx_packet_last == NX_NULL)
176 {
177 packet_ptr -> nx_packet_last = work_ptr;
178 }
179 #else /* NX_DISABLE_PACKET_CHAIN */
180
181 /* Return error code. */
182 return(NX_UNDERFLOW);
183 #endif /* !NX_DISABLE_PACKET_CHAIN */
184 }
185
186 /* Return successful completion. */
187 return(NX_SUCCESS);
188 }
189
190
