1 /* 2 * FreeRTOS+TCP <DEVELOPMENT BRANCH> 3 * Copyright (C) 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. 4 * 5 * SPDX-License-Identifier: MIT 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy of 8 * this software and associated documentation files (the "Software"), to deal in 9 * the Software without restriction, including without limitation the rights to 10 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 11 * the Software, and to permit persons to whom the Software is furnished to do so, 12 * subject to the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in all 15 * copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS 19 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR 20 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 21 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 22 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 * 24 * https://www.FreeRTOS.org 25 * https://github.com/FreeRTOS 26 */ 27 28 #ifndef FREERTOS_IPV4_PRIVATE_H 29 #define FREERTOS_IPV4_PRIVATE_H 30 31 #include "FreeRTOS_IP_Private.h" 32 33 /* *INDENT-OFF* */ 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 /* *INDENT-ON* */ 38 39 /* The maximum UDP payload length. */ 40 #define ipMAX_UDP_PAYLOAD_LENGTH ( ( ipconfigNETWORK_MTU - ipSIZE_OF_IPv4_HEADER ) - ipSIZE_OF_UDP_HEADER ) 41 42 #define TCP_PACKET_SIZE ( sizeof( TCPPacket_t ) ) 43 44 /* The offset into an IP packet into which the IP data (payload) starts. */ 45 #define ipIP_PAYLOAD_OFFSET ( sizeof( IPPacket_t ) ) 46 /* The offset into a UDP packet at which the UDP data (payload) starts. */ 47 #define ipUDP_PAYLOAD_OFFSET_IPv4 ( sizeof( UDPPacket_t ) ) 48 /* The value of 'ipUDP_PAYLOAD_IP_TYPE_OFFSET' is 8 + 40 = 48 bytes. */ 49 #define ipUDP_PAYLOAD_IP_TYPE_OFFSET ( sizeof( UDPHeader_t ) + sizeof( IPHeader_IPv6_t ) ) 50 51 /* ipIP_TYPE_OFFSET is involved in some sorcery. pxUDPPayloadBuffer_to_NetworkBuffer() must be able to convert 52 * a payload pointer ( like for example a pointer to the DNS payload of a packet ) back to a NetworkBufferDescriptor_t. 53 * This must work for both IPv4 and IPv6 packets. The pointer conversion is done by subtracting a constant from the payload pointer. 54 * For IPv6, this magic number is ( sizeof( UDPHeader_t ) + sizeof( IPHeader_IPv6_t ) ) which equals 48 bytes. 55 * If however we use that same constant for an IPv4 packet, we end up somewhere in front of the Ethernet header. 56 * In order to accommodate that, the Ethernet frame buffer gets allocated a bit larger than needed. 57 * For IPv4 frames, prvProcessIPPacket() stores the version header field at a negative offset, a few bytes before the start 58 * of the Ethernet header. That IPv4 version field MUST be stored the same distance from the payload as in IPv6. 59 * ipIP_TYPE_OFFSET must be equal to: sizeof( UDPHeader_t ) + sizeof( IPHeader_IPv6_t ) - ( sizeof( UDPPacket_t ) 60 * In most situations, ipIP_TYPE_OFFSET will end up being equal to 6. If the Ethernet header is enlarged to include VLAN 61 * tag support, ipIP_TYPE_OFFSET will shrink to 2. With the current design, the Ethernet header cannot be expanded to contain 62 * more than one VLAN tag or ipIP_TYPE_OFFSET will become less than zero. ipIP_TYPE_OFFSET should never be allowed to be <= 0 63 * or storing of the IPv4 version byte will overwrite the Ethernet header of the frame. 64 */ 65 #define ipIP_TYPE_OFFSET ( ( int32_t ) sizeof( UDPHeader_t ) + ( int32_t ) sizeof( IPHeader_IPv6_t ) - ( int32_t ) sizeof( UDPPacket_t ) ) 66 67 #include "pack_struct_start.h" 68 struct xIP_HEADER 69 { 70 uint8_t ucVersionHeaderLength; /**< The version field + internet header length 0 + 1 = 1 */ 71 uint8_t ucDifferentiatedServicesCode; /**< Differentiated services code point + ECN 1 + 1 = 2 */ 72 uint16_t usLength; /**< Entire Packet size, ex. Ethernet header. 2 + 2 = 4 */ 73 uint16_t usIdentification; /**< Identification field 4 + 2 = 6 */ 74 uint16_t usFragmentOffset; /**< Fragment flags and fragment offset 6 + 2 = 8 */ 75 uint8_t ucTimeToLive; /**< Time to live field 8 + 1 = 9 */ 76 uint8_t ucProtocol; /**< Protocol used in the IP-datagram 9 + 1 = 10 */ 77 uint16_t usHeaderChecksum; /**< Checksum of the IP-header 10 + 2 = 12 */ 78 uint32_t ulSourceIPAddress; /**< IP address of the source 12 + 4 = 16 */ 79 uint32_t ulDestinationIPAddress; /**< IP address of the destination 16 + 4 = 20 */ 80 } 81 #include "pack_struct_end.h" 82 typedef struct xIP_HEADER IPHeader_t; 83 84 /*-----------------------------------------------------------*/ 85 /* Nested protocol packets. */ 86 /*-----------------------------------------------------------*/ 87 88 #include "pack_struct_start.h" 89 struct xIP_PACKET 90 { 91 EthernetHeader_t xEthernetHeader; 92 IPHeader_t xIPHeader; 93 } 94 #include "pack_struct_end.h" 95 typedef struct xIP_PACKET IPPacket_t; 96 97 #include "pack_struct_start.h" 98 struct xICMP_PACKET 99 { 100 EthernetHeader_t xEthernetHeader; /**< The Ethernet header of an ICMP packet. */ 101 IPHeader_t xIPHeader; /**< The IP header of an ICMP packet. */ 102 ICMPHeader_t xICMPHeader; /**< The ICMP header of an ICMP packet. */ 103 } 104 #include "pack_struct_end.h" 105 typedef struct xICMP_PACKET ICMPPacket_t; 106 107 108 #include "pack_struct_start.h" 109 struct xUDP_PACKET 110 { 111 EthernetHeader_t xEthernetHeader; /**< UDP-Packet ethernet header 0 + 14 = 14 */ 112 IPHeader_t xIPHeader; /**< UDP-Packet IP header 14 + 20 = 34 */ 113 UDPHeader_t xUDPHeader; /**< UDP-Packet UDP header 34 + 8 = 42 */ 114 } 115 #include "pack_struct_end.h" 116 typedef struct xUDP_PACKET UDPPacket_t; 117 118 #include "pack_struct_start.h" 119 struct xTCP_PACKET 120 { 121 EthernetHeader_t xEthernetHeader; /**< The ethernet header 0 + 14 = 14 */ 122 IPHeader_t xIPHeader; /**< The IP header 14 + 20 = 34 */ 123 TCPHeader_t xTCPHeader; /**< The TCP header 34 + 32 = 66 */ 124 } 125 #include "pack_struct_end.h" 126 typedef struct xTCP_PACKET TCPPacket_t; 127 128 /* *INDENT-OFF* */ 129 #ifdef __cplusplus 130 } /* extern "C" */ 131 #endif 132 /* *INDENT-ON* */ 133 134 #endif /* FREERTOS_IP_PRIVATE_H */ 135
