Martin Michelsen
102 lines
2.5 KiB
C++
102 lines
2.5 KiB
C++
#pragma once
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#include <stdint.h>
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#include <phosg/Encoding.hh>
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struct EthernetHeader {
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uint8_t dest_mac[6];
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uint8_t src_mac[6];
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be_uint16_t protocol;
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} __attribute__((packed));
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struct ARPHeader {
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be_uint16_t hardware_type;
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be_uint16_t protocol_type; // same as EthernetHeader::protocol
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uint8_t hwaddr_len;
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uint8_t paddr_len;
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be_uint16_t operation;
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} __attribute__((packed));
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struct IPv4Header {
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uint8_t version_ihl;
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uint8_t tos;
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be_uint16_t size;
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be_uint16_t id;
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be_uint16_t frag_offset;
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uint8_t ttl;
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uint8_t protocol;
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be_uint16_t checksum;
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be_uint32_t src_addr;
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be_uint32_t dest_addr;
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} __attribute__((packed));
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struct UDPHeader {
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be_uint16_t src_port;
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be_uint16_t dest_port;
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be_uint16_t size;
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be_uint16_t checksum;
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} __attribute__((packed));
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struct TCPHeader {
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enum Flag {
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NS = 0x0100,
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CWR = 0x0080, // congestion window reduced
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ECE = 0x0040, // ECN capable / congestion experienced
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URG = 0x0020, // urgent pointer used
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ACK = 0x0010, // ack_num is valid
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PSH = 0x0008, // sending data
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RST = 0x0004, // reset (hard disconnect)
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SYN = 0x0002, // synchronize sequence numbers (open connection)
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FIN = 0x0001, // close (normal disconnect)
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};
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be_uint16_t src_port;
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be_uint16_t dest_port;
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be_uint32_t seq_num;
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be_uint32_t ack_num;
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be_uint16_t flags;
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be_uint16_t window;
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be_uint16_t checksum;
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be_uint16_t urgent_ptr;
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} __attribute__((packed));
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struct FrameInfo {
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// This is always valid
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const EthernetHeader* ether;
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uint16_t ether_protocol;
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// At most one of these is not null
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const IPv4Header* ipv4;
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const ARPHeader* arp;
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// One of these may be not null if this->ipv4 is not null
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const UDPHeader* udp;
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const TCPHeader* tcp;
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const void* header_start;
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const void* payload;
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size_t total_size;
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size_t tcp_options_size;
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size_t payload_size;
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FrameInfo();
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FrameInfo(const std::string& data);
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FrameInfo(const void* data, size_t size);
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std::string header_str() const;
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void truncate(size_t new_total_size);
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size_t size_from_header() const;
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static uint16_t computed_ipv4_header_checksum(const IPv4Header& ipv4);
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uint16_t computed_ipv4_header_checksum() const;
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static uint16_t computed_udp4_checksum(
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const IPv4Header& ipv4, const UDPHeader& udp, const void* data, size_t size);
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uint16_t computed_udp4_checksum() const;
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static uint16_t computed_tcp4_checksum(
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const IPv4Header& ip, const TCPHeader& tcp, const void* data, size_t size);
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uint16_t computed_tcp4_checksum() const;
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};
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