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 /** Packet Pool Management (Packet) */
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_packet.h"
30
31
32 /**************************************************************************/
33 /* */
34 /* FUNCTION RELEASE */
35 /* */
36 /* _nx_packet_data_adjust PORTABLE C */
37 /* 6.1 */
38 /* AUTHOR */
39 /* */
40 /* Yuxin Zhou, Microsoft Corporation */
41 /* */
42 /* DESCRIPTION */
43 /* */
44 /* This function adjusts the packet data to fill the specified header. */
45 /* */
46 /* INPUT */
47 /* */
48 /* packet_ptr Pointer to the source packet */
49 /* header_size The size of header */
50 /* */
51 /* OUTPUT */
52 /* */
53 /* status Completion status */
54 /* */
55 /* CALLS */
56 /* */
57 /* _nx_packet_allocate Allocate data packet */
58 /* _nx_packet_data_append Packet data append service */
59 /* _nx_packet_release Release data packet */
60 /* */
61 /* CALLED BY */
62 /* */
63 /* _nx_ip_forward_packet_process Forward IP packet */
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), and */
71 /* verified memcpy use cases, */
72 /* verified memmove use cases, */
73 /* resulting in version 6.1 */
74 /* */
75 /**************************************************************************/
_nx_packet_data_adjust(NX_PACKET * packet_ptr,ULONG header_size)76 UINT _nx_packet_data_adjust(NX_PACKET *packet_ptr, ULONG header_size)
77 {
78
79 ULONG available_size;
80 ULONG shift_size;
81 #ifndef NX_DISABLE_PACKET_CHAIN
82 UINT status;
83 ULONG append_size;
84 UCHAR *data_start;
85 NX_PACKET *work_ptr;
86 #endif /* !NX_DISABLE_PACKET_CHAIN */
87
88
89 /* Add debug information. */
90 NX_PACKET_DEBUG(__FILE__, __LINE__, packet_ptr);
91
92 /* The header must be filled in one packet. */
93 if (((ALIGN_TYPE)packet_ptr -> nx_packet_data_end - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) < header_size)
94 {
95 return(NX_UNDERFLOW);
96 }
97
98 /* 1. Check if there is enough space to add header. */
99 if (((ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) >= header_size)
100 {
101
102 /* Yes. Just return success. */
103 return(NX_SUCCESS);
104 }
105
106 /* Compute the total avilable size in this packet. */
107 available_size = (ULONG)(((ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_data_start) +
108 ((ALIGN_TYPE)packet_ptr -> nx_packet_data_end - (ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr));
109
110 /* 2. Would the header fit into the available space? */
111 if (available_size >= header_size)
112 {
113
114 /* Yes, adjust the data. */
115
116 /* Calculate the shift data size. */
117 shift_size = (ULONG)((ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr);
118
119 /* Move the data, */
120 memmove(packet_ptr -> nx_packet_data_start + header_size, packet_ptr -> nx_packet_prepend_ptr, shift_size); /* Use case of memmove is verified. */
121
122 /* Update the prepend and append pointer. */
123 packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_data_start + header_size;
124 packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_prepend_ptr + shift_size;
125 }
126 else
127 {
128
129 #ifndef NX_DISABLE_PACKET_CHAIN
130
131 /* 3. Current packet does not have enough space to fill the header.
132 Allocate a new packet to fill the overflowing data and chain the packet. */
133
134 /* Odd value of header_size is not supported now.
135 * In _nx_ip_checksum_compute(), nx_packet_append_ptr must not be odd value. */
136 if (header_size & 1)
137 {
138 return(NX_NOT_SUPPORTED);
139 }
140
141 /* Calculate the append data size. */
142 append_size = header_size - available_size;
143
144 /* Set the append data pointer. */
145 data_start = packet_ptr -> nx_packet_append_ptr - append_size;
146
147 /* Allocate a packet. */
148 status = _nx_packet_allocate(packet_ptr -> nx_packet_pool_owner, &work_ptr, 0, NX_NO_WAIT);
149
150 /* Check status. */
151 if (status)
152 {
153 return(status);
154 }
155
156 /* Firstly, append the overflowing data to the new packet.. */
157 memcpy(work_ptr -> nx_packet_prepend_ptr, data_start, append_size); /* Use case of memcpy is verified. lgtm[cpp/banned-api-usage-required-any] */
158 work_ptr -> nx_packet_append_ptr = (UCHAR *)((ALIGN_TYPE)work_ptr -> nx_packet_prepend_ptr + append_size);
159
160 /* Secondly, calculate the shift data size. */
161 shift_size = (ULONG)(((ALIGN_TYPE)packet_ptr -> nx_packet_append_ptr - (ALIGN_TYPE)packet_ptr -> nx_packet_prepend_ptr) - append_size);
162
163 /* Move the data. */
164 memmove(packet_ptr -> nx_packet_data_start + header_size, packet_ptr -> nx_packet_prepend_ptr, shift_size); /* Use case of memmove is verified. */
165
166 /* Update the prepend and append pointer. */
167 packet_ptr -> nx_packet_prepend_ptr = packet_ptr -> nx_packet_data_start + header_size;
168 packet_ptr -> nx_packet_append_ptr = packet_ptr -> nx_packet_prepend_ptr + shift_size;
169
170 /* At this point, all the necessary packets have been allocated.
171 We need to link this new packet to the next of the supplied packet. */
172 work_ptr -> nx_packet_next = packet_ptr -> nx_packet_next;
173 packet_ptr -> nx_packet_next = work_ptr;
174
175 /* Update the last packet pointer. */
176 if (packet_ptr -> nx_packet_last == NX_NULL)
177 {
178 packet_ptr -> nx_packet_last = work_ptr;
179 }
180 #else /* NX_DISABLE_PACKET_CHAIN */
181
182 /* Return error code. */
183 return(NX_UNDERFLOW);
184 #endif /* !NX_DISABLE_PACKET_CHAIN */
185 }
186
187 /* Return successful completion. */
188 return(NX_SUCCESS);
189 }
190
191
