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 /** Address Resolution Protocol (ARP) */
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_arp.h"
30
31 #ifndef NX_DISABLE_IPV4
32 /**************************************************************************/
33 /* */
34 /* FUNCTION RELEASE */
35 /* */
36 /* _nx_arp_entry_allocate PORTABLE C */
37 /* 6.1 */
38 /* AUTHOR */
39 /* */
40 /* Yuxin Zhou, Microsoft Corporation */
41 /* */
42 /* DESCRIPTION */
43 /* */
44 /* This function allocates an ARP entry for a specific new IP */
45 /* destination. */
46 /* */
47 /* INPUT */
48 /* */
49 /* ip_ptr IP instance pointer */
50 /* arp_list_ptr List head of where to place */
51 /* the newly allocated ARP */
52 /* entry */
53 /* is_static Entry attribute static/dynamic*/
54 /* */
55 /* OUTPUT */
56 /* */
57 /* status Completion status */
58 /* */
59 /* CALLS */
60 /* */
61 /* _nx_arp_dynamic_entry_delete Delete the dynamic entry */
62 /* */
63 /* CALLED BY */
64 /* */
65 /* NetX Source Code */
66 /* */
67 /* RELEASE HISTORY */
68 /* */
69 /* DATE NAME DESCRIPTION */
70 /* */
71 /* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
72 /* 09-30-2020 Yuxin Zhou Modified comment(s), */
73 /* resulting in version 6.1 */
74 /* */
75 /**************************************************************************/
_nx_arp_entry_allocate(NX_IP * ip_ptr,NX_ARP ** arp_list_ptr,UINT is_static)76 UINT _nx_arp_entry_allocate(NX_IP *ip_ptr, NX_ARP **arp_list_ptr, UINT is_static)
77 {
78
79 TX_INTERRUPT_SAVE_AREA
80 NX_ARP *arp_entry;
81 UINT status;
82
83
84 /* Determine if there is an ARP entry available in the dynamic list. */
85 if (ip_ptr -> nx_ip_arp_dynamic_list)
86 {
87
88 /* Yes there are one or more free entries. */
89
90 /* Pickup pointer to last used dynamic ARP entry. */
91 arp_entry = (ip_ptr -> nx_ip_arp_dynamic_list) -> nx_arp_pool_previous;
92
93 /* Remove from the dynamic list. */
94 _nx_arp_dynamic_entry_delete(ip_ptr, arp_entry);
95
96 /* Disable interrupts temporarily. */
97 TX_DISABLE
98
99 /* Link the ARP entry at the head of the IP list. */
100
101 /* Determine if the ARP entry is being added to an empty list. */
102 if (*arp_list_ptr)
103 {
104
105 /* Add the ARP entry to the beginning of the nonempty ARP
106 list. */
107 arp_entry -> nx_arp_active_list_head = arp_list_ptr;
108 arp_entry -> nx_arp_active_next = *arp_list_ptr;
109 arp_entry -> nx_arp_active_previous = (*arp_list_ptr) -> nx_arp_active_previous;
110 (arp_entry -> nx_arp_active_previous) -> nx_arp_active_next = arp_entry;
111 (*arp_list_ptr) -> nx_arp_active_previous = arp_entry;
112 }
113 else
114 {
115 /* Empty list, just put the ARP entry at the beginning. */
116 arp_entry -> nx_arp_active_list_head = arp_list_ptr;
117 arp_entry -> nx_arp_active_next = arp_entry;
118 arp_entry -> nx_arp_active_previous = arp_entry;
119
120 /* Now setup the list head. */
121 *arp_list_ptr = arp_entry;
122 }
123
124 /* Determine if this is a static entry. */
125 if (is_static == NX_TRUE)
126 {
127
128 /* Remove this entry from the ARP dynamic list. */
129
130 /* Determine if this is the only ARP entry on the dynamic list. */
131 if (arp_entry == arp_entry -> nx_arp_pool_next)
132 {
133
134 /* Remove the sole entry from the dynamic list head. */
135 ip_ptr -> nx_ip_arp_dynamic_list = NX_NULL;
136 }
137 else
138 {
139
140 /* Remove the entry from a list of more than one entry. */
141
142 /* Update the links of the adjacent ARP dynamic pool entries. */
143 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry -> nx_arp_pool_previous;
144 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry -> nx_arp_pool_next;
145 }
146
147 /* Add the entry to the ARP static list. */
148
149 /* Determine if the ARP static list is empty. */
150 if (ip_ptr -> nx_ip_arp_static_list == NX_NULL)
151 {
152
153 /* Just place this single ARP entry on the list. */
154 arp_entry -> nx_arp_pool_next = arp_entry;
155 arp_entry -> nx_arp_pool_previous = arp_entry;
156 ip_ptr -> nx_ip_arp_static_list = arp_entry;
157 }
158 else
159 {
160
161 /* Add to the end of the ARP static list. */
162 arp_entry -> nx_arp_pool_next = ip_ptr -> nx_ip_arp_static_list;
163 arp_entry -> nx_arp_pool_previous = (ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous;
164 ((ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry;
165 (ip_ptr -> nx_ip_arp_static_list) -> nx_arp_pool_previous = arp_entry;
166 }
167
168 #ifndef NX_DISABLE_ARP_INFO
169 /* Increment the ARP static entry count. */
170 ip_ptr -> nx_ip_arp_static_entries++;
171 #endif
172 }
173 else /* Allocate entry from dynamic list. */
174 {
175
176 /* Move this ARP entry to the front of the general ARP dynamic entry pool. */
177 if (arp_entry != ip_ptr -> nx_ip_arp_dynamic_list)
178 {
179
180 /* The current ARP entry is not at the front of the list, so it
181 must be moved. */
182
183 /* Link up the neighbors first. */
184 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry -> nx_arp_pool_previous;
185 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry -> nx_arp_pool_next;
186
187 /* Now link this ARP entry to the head of the list. */
188 arp_entry -> nx_arp_pool_next = ip_ptr -> nx_ip_arp_dynamic_list;
189 arp_entry -> nx_arp_pool_previous = (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous;
190 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry;
191 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = arp_entry;
192
193 /* Now set the list head to this ARP entry. */
194 ip_ptr -> nx_ip_arp_dynamic_list = arp_entry;
195 }
196
197 /* Increment the number of active dynamic entries. */
198 ip_ptr -> nx_ip_arp_dynamic_active_count++;
199 }
200
201 /* Set the entry type. */
202 arp_entry -> nx_arp_route_static = is_static;
203
204 /* Restore interrupts. */
205 TX_RESTORE
206
207 /* Setup a successful status return. */
208 status = NX_SUCCESS;
209 }
210 else
211 {
212
213 /* No more ARP entries are available, all the ARP entries must be
214 allocated on the static list. */
215 status = NX_NO_MORE_ENTRIES;
216 }
217
218 /* Return status to the caller. */
219 return(status);
220 }
221 #endif /* !NX_DISABLE_IPV4 */
222
223
