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git.proxmox.com Git - mirror_edk2.git/blob - MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Option.c
611887b71b3814f269f891f5b9bb784f29833bf6
2 IP4 option support functions.
4 Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
19 Validate the IP4 option format for both the packets we received
22 @param[in] Option The first byte of the option
23 @param[in] OptionLen The length of the whole option
24 @param[in] Rcvd The option is from the packet we received if TRUE,
25 otherwise the option we wants to transmit.
27 @retval TRUE The option is properly formatted
28 @retval FALSE The option is mal-formated
44 while (Cur
< OptionLen
) {
45 switch (Option
[Cur
]) {
57 Len
= Option
[Cur
+ 1];
58 Point
= Option
[Cur
+ 2];
61 // SRR/RR options are formatted as |Type|Len|Point|Ip1|Ip2|...
63 if ((OptionLen
- Cur
< Len
) || (Len
< 3) || ((Len
- 3) % 4 != 0)) {
67 if ((Point
> Len
+ 1) || (Point
% 4 != 0)) {
72 // The Point must point pass the last entry if the packet is received
73 // by us. It must point to 4 if the packet is to be sent by us for
74 // source route option.
76 if ((Option
[Cur
] != IP4_OPTION_RR
) &&
77 ((Rcvd
&& (Point
!= Len
+ 1)) || (!Rcvd
&& (Point
!= 4)))) {
86 Len
= Option
[Cur
+ 1];
88 if ((OptionLen
- Cur
< Len
) || (Len
< 2)) {
103 Copy the option from the original option to buffer. It
104 handles the details such as:
105 1. whether copy the single IP4 option to the first/non-first
107 2. Pad the options copied over to aligned to 4 bytes.
109 @param[in] Option The original option to copy from
110 @param[in] OptionLen The length of the original option
111 @param[in] FirstFragment Whether it is the first fragment
112 @param[in, out] Buf The buffer to copy options to. NULL
113 @param[in, out] BufLen The length of the buffer
115 @retval EFI_SUCCESS The options are copied over
116 @retval EFI_BUFFER_TOO_SMALL Buf is NULL or BufLen provided is too small.
123 IN BOOLEAN FirstFragment
,
124 IN OUT UINT8
*Buf
, OPTIONAL
125 IN OUT UINT32
*BufLen
134 ASSERT ((BufLen
!= NULL
) && (OptionLen
<= 40));
139 while (Cur
< OptionLen
) {
141 Len
= Option
[Cur
+ 1];
143 if (Type
== IP4_OPTION_NOP
) {
145 // Keep the padding, in case that the sender wants to align
146 // the option, say, to 4 bytes
148 OptBuf
[Next
] = IP4_OPTION_NOP
;
152 } else if (Type
== IP4_OPTION_EOP
) {
154 // Don't append the EOP to avoid including only a EOP option
160 // don't copy options that is only valid for the first fragment
162 if (FirstFragment
|| (Type
& IP4_OPTION_COPY_MASK
) != 0) {
163 CopyMem (OptBuf
+ Next
, Option
+ Cur
, Len
);
172 // Don't append an EOP only option.
180 // Append an EOP if the end of option doesn't coincide with the
181 // end of the IP header, that is, isn't aligned to 4 bytes..
183 if ((Next
% 4) != 0) {
184 OptBuf
[Next
] = IP4_OPTION_EOP
;
189 // Head length is in the unit of 4 bytes. Now, Len is the
190 // acutal option length to appear in the IP header.
192 Len
= ((Next
+ 3) &~0x03);
195 // If the buffer is too small, set the BufLen then return
197 if ((Buf
== NULL
) || (*BufLen
< Len
)) {
199 return EFI_BUFFER_TOO_SMALL
;
203 // Copy the option to the Buf, zero the buffer first to pad
204 // the options with NOP to align to 4 bytes.
207 CopyMem (Buf
, OptBuf
, Next
);