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 /** Address Resolution Protocol (ARP) */
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_arp.h"
29
30 #ifndef NX_DISABLE_IPV4
31 /**************************************************************************/
32 /* */
33 /* FUNCTION RELEASE */
34 /* */
35 /* _nx_arp_entry_allocate PORTABLE C */
36 /* 6.1 */
37 /* AUTHOR */
38 /* */
39 /* Yuxin Zhou, Microsoft Corporation */
40 /* */
41 /* DESCRIPTION */
42 /* */
43 /* This function allocates an ARP entry for a specific new IP */
44 /* destination. */
45 /* */
46 /* INPUT */
47 /* */
48 /* ip_ptr IP instance pointer */
49 /* arp_list_ptr List head of where to place */
50 /* the newly allocated ARP */
51 /* entry */
52 /* is_static Entry attribute static/dynamic*/
53 /* */
54 /* OUTPUT */
55 /* */
56 /* status Completion status */
57 /* */
58 /* CALLS */
59 /* */
60 /* _nx_arp_dynamic_entry_delete Delete the dynamic entry */
61 /* */
62 /* CALLED BY */
63 /* */
64 /* NetX Source Code */
65 /* */
66 /* RELEASE HISTORY */
67 /* */
68 /* DATE NAME DESCRIPTION */
69 /* */
70 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
71 /* 09-30-2020 Yuxin Zhou Modified comment(s), */
72 /* resulting in version 6.1 */
73 /* */
74 /**************************************************************************/
_nx_arp_entry_allocate(NX_IP * ip_ptr,NX_ARP ** arp_list_ptr,UINT is_static)75 UINT _nx_arp_entry_allocate(NX_IP *ip_ptr, NX_ARP **arp_list_ptr, UINT is_static)
76 {
77
78 TX_INTERRUPT_SAVE_AREA
79 NX_ARP *arp_entry;
80 UINT status;
81
82
83 /* Determine if there is an ARP entry available in the dynamic list. */
84 if (ip_ptr -> nx_ip_arp_dynamic_list)
85 {
86
87 /* Yes there are one or more free entries. */
88
89 /* Pickup pointer to last used dynamic ARP entry. */
90 arp_entry = (ip_ptr -> nx_ip_arp_dynamic_list) -> nx_arp_pool_previous;
91
92 /* Remove from the dynamic list. */
93 _nx_arp_dynamic_entry_delete(ip_ptr, arp_entry);
94
95 /* Disable interrupts temporarily. */
96 TX_DISABLE
97
98 /* Link the ARP entry at the head of the IP list. */
99
100 /* Determine if the ARP entry is being added to an empty list. */
101 if (*arp_list_ptr)
102 {
103
104 /* Add the ARP entry to the beginning of the nonempty ARP
105 list. */
106 arp_entry -> nx_arp_active_list_head = arp_list_ptr;
107 arp_entry -> nx_arp_active_next = *arp_list_ptr;
108 arp_entry -> nx_arp_active_previous = (*arp_list_ptr) -> nx_arp_active_previous;
109 (arp_entry -> nx_arp_active_previous) -> nx_arp_active_next = arp_entry;
110 (*arp_list_ptr) -> nx_arp_active_previous = arp_entry;
111 }
112 else
113 {
114 /* Empty list, just put the ARP entry at the beginning. */
115 arp_entry -> nx_arp_active_list_head = arp_list_ptr;
116 arp_entry -> nx_arp_active_next = arp_entry;
117 arp_entry -> nx_arp_active_previous = arp_entry;
118
119 /* Now setup the list head. */
120 *arp_list_ptr = arp_entry;
121 }
122
123 /* Determine if this is a static entry. */
124 if (is_static == NX_TRUE)
125 {
126
127 /* Remove this entry from the ARP dynamic list. */
128
129 /* Determine if this is the only ARP entry on the dynamic list. */
130 if (arp_entry == arp_entry -> nx_arp_pool_next)
131 {
132
133 /* Remove the sole entry from the dynamic list head. */
134 ip_ptr -> nx_ip_arp_dynamic_list = NX_NULL;
135 }
136 else
137 {
138
139 /* Remove the entry from a list of more than one entry. */
140
141 /* Update the links of the adjacent ARP dynamic pool entries. */
142 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry -> nx_arp_pool_previous;
143 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry -> nx_arp_pool_next;
144 }
145
146 /* Add the entry to the ARP static list. */
147
148 /* Determine if the ARP static list is empty. */
149 if (ip_ptr -> nx_ip_arp_static_list == NX_NULL)
150 {
151
152 /* Just place this single ARP entry on the list. */
153 arp_entry -> nx_arp_pool_next = arp_entry;
154 arp_entry -> nx_arp_pool_previous = arp_entry;
155 ip_ptr -> nx_ip_arp_static_list = arp_entry;
156 }
157 else
158 {
159
160 /* Add to the end of the ARP static list. */
161 arp_entry -> nx_arp_pool_next = ip_ptr -> nx_ip_arp_static_list;
162 arp_entry -> nx_arp_pool_previous = (ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous;
163 ((ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry;
164 (ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous = arp_entry;
165 }
166
167 #ifndef NX_DISABLE_ARP_INFO
168 /* Increment the ARP static entry count. */
169 ip_ptr -> nx_ip_arp_static_entries++;
170 #endif
171 }
172 else /* Allocate entry from dynamic list. */
173 {
174
175 /* Move this ARP entry to the front of the general ARP dynamic entry pool. */
176 if (arp_entry != ip_ptr -> nx_ip_arp_dynamic_list)
177 {
178
179 /* The current ARP entry is not at the front of the list, so it
180 must be moved. */
181
182 /* Link up the neighbors first. */
183 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry -> nx_arp_pool_previous;
184 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry -> nx_arp_pool_next;
185
186 /* Now link this ARP entry to the head of the list. */
187 arp_entry -> nx_arp_pool_next = ip_ptr -> nx_ip_arp_dynamic_list;
188 arp_entry -> nx_arp_pool_previous = (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous;
189 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry;
190 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry;
191
192 /* Now set the list head to this ARP entry. */
193 ip_ptr -> nx_ip_arp_dynamic_list = arp_entry;
194 }
195
196 /* Increment the number of active dynamic entries. */
197 ip_ptr -> nx_ip_arp_dynamic_active_count++;
198 }
199
200 /* Set the entry type. */
201 arp_entry -> nx_arp_route_static = is_static;
202
203 /* Restore interrupts. */
204 TX_RESTORE
205
206 /* Setup a successful status return. */
207 status = NX_SUCCESS;
208 }
209 else
210 {
211
212 /* No more ARP entries are available, all the ARP entries must be
213 allocated on the static list. */
214 status = NX_NO_MORE_ENTRIES;
215 }
216
217 /* Return status to the caller. */
218 return(status);
219 }
220 #endif /* !NX_DISABLE_IPV4 */
221
222
