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 /* 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_static_entry_delete_internal PORTABLE C */ 36 /* 6.1 */ 37 /* AUTHOR */ 38 /* */ 39 /* Yuxin Zhou, Microsoft Corporation */ 40 /* */ 41 /* DESCRIPTION */ 42 /* */ 43 /* This function deletes the ARP entry pointed to by the caller. Note */ 44 /* the caller should already have searched the ARP list to verify a */ 45 /* valid ARP entry to delete. Also, it is assumed the caller already */ 46 /* has obtained the IP protection mutex before invoking this service. */ 47 /* */ 48 /* INPUT */ 49 /* */ 50 /* ip_ptr IP instance owner of APR table*/ 51 /* arp_entry ARP entry to delete */ 52 /* */ 53 /* OUTPUT */ 54 /* */ 55 /* None */ 56 /* */ 57 /* CALLS */ 58 /* */ 59 /* None */ 60 /* */ 61 /* CALLED BY */ 62 /* */ 63 /* _nx_arp_interface_entries_delete Delete ARP entry associated */ 64 /* with the specified interface*/ 65 /* _nx_arp_static_entry_delete Delete static ARP entry */ 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_static_entry_delete_internal(NX_IP * ip_ptr,NX_ARP * arp_entry)76VOID _nx_arp_static_entry_delete_internal(NX_IP *ip_ptr, NX_ARP *arp_entry) 77 { 78 79 TX_INTERRUPT_SAVE_AREA 80 81 82 #ifndef NX_DISABLE_ARP_INFO 83 /* Decrement the ARP static entry count. */ 84 ip_ptr -> nx_ip_arp_static_entries--; 85 #endif 86 87 /* Disable interrupts temporarily. */ 88 TX_DISABLE 89 90 /* Determine if this ARP entry is already active. */ 91 if (arp_entry -> nx_arp_active_list_head) 92 { 93 94 /* Remove this dynamic ARP entry from the associated list. */ 95 96 /* Determine if this is the only ARP entry on the list. */ 97 if (arp_entry == arp_entry -> nx_arp_active_next) 98 { 99 100 /* Remove the entry from the list. */ 101 *(arp_entry -> nx_arp_active_list_head) = NX_NULL; 102 } 103 else 104 { 105 106 /* Remove the entry from a list of more than one entry. */ 107 108 /* Update the list head pointer. */ 109 if (*(arp_entry -> nx_arp_active_list_head) == arp_entry) 110 { 111 *(arp_entry -> nx_arp_active_list_head) = arp_entry -> nx_arp_active_next; 112 } 113 114 /* Update the links of the adjacent ARP entries. */ 115 (arp_entry -> nx_arp_active_next) -> nx_arp_active_previous = 116 arp_entry -> nx_arp_active_previous; 117 (arp_entry -> nx_arp_active_previous) -> nx_arp_active_next = 118 arp_entry -> nx_arp_active_next; 119 } 120 } 121 122 /* Remove this entry from the static ARP list. */ 123 124 /* Determine if this is the only ARP entry on the static list. */ 125 if (arp_entry == arp_entry -> nx_arp_pool_next) 126 { 127 128 /* Remove the sole entry from the static list head. */ 129 ip_ptr -> nx_ip_arp_static_list = NX_NULL; 130 } 131 else 132 { 133 134 /* Remove the entry from a list of more than one entry. */ 135 136 /* Update the links of the adjacent ARP dynamic pool entries. */ 137 (arp_entry -> nx_arp_pool_next) -> nx_arp_pool_previous = 138 arp_entry -> nx_arp_pool_previous; 139 (arp_entry -> nx_arp_pool_previous) -> nx_arp_pool_next = 140 arp_entry -> nx_arp_pool_next; 141 142 /* Update the list head pointer. */ 143 if (ip_ptr -> nx_ip_arp_static_list == arp_entry) 144 { 145 ip_ptr -> nx_ip_arp_static_list = arp_entry -> nx_arp_pool_next; 146 } 147 } 148 149 /* Clear the fields that indicate the ARP entry is a static entry and make sure 150 it is viewed as inactive in preparation for returning it to the dynamic ARP 151 pool. */ 152 arp_entry -> nx_arp_route_static = NX_FALSE; 153 arp_entry -> nx_arp_active_list_head = NX_NULL; 154 155 /* Place the ARP entry at the end of the dynamic ARP pool, which is where new 156 ARP requests are allocated from. */ 157 158 /* Determine if the dynamic ARP pool is empty. */ 159 if (ip_ptr -> nx_ip_arp_dynamic_list) 160 { 161 162 /* Dynamic list is not empty, add former static ARP entry to the end of the list. */ 163 arp_entry -> nx_arp_pool_next = ip_ptr -> nx_ip_arp_dynamic_list; 164 arp_entry -> nx_arp_pool_previous = (ip_ptr -> nx_ip_arp_dynamic_list) -> nx_arp_pool_previous; 165 ((ip_ptr -> nx_ip_arp_dynamic_list) -> nx_arp_pool_previous) -> nx_arp_pool_next = arp_entry; 166 (ip_ptr -> nx_ip_arp_dynamic_list) -> nx_arp_pool_previous = arp_entry; 167 } 168 else 169 { 170 171 /* Dynamic list was empty, just place it at the head of the dynamic list. */ 172 ip_ptr -> nx_ip_arp_dynamic_list = arp_entry; 173 arp_entry -> nx_arp_pool_next = arp_entry; 174 arp_entry -> nx_arp_pool_previous = arp_entry; 175 } 176 177 /* Restore interrupts. */ 178 TX_RESTORE 179 } 180 #endif /* !NX_DISABLE_IPV4 */ 181 182
