Wiesner András
05288d7a3c
- IGMPv2 capabilities added (report membership, leave group) - ICMP capabilities added (ping) - Tx Message Queue added
59 lines
2.0 KiB
C
59 lines
2.0 KiB
C
#include <stdbool.h>
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#include "udp_packet.h"
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#include "../../utils.h"
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#include "ipv4_packet.h"
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#include "ethernet_frame.h"
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#define ETH_UDP_HEADER_SIZE (8)
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typedef struct {
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uint32_t sourceIpAddr;
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uint32_t destIpAddr;
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uint8_t zero;
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uint8_t protocol;
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uint16_t udpLength;
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} UdpPseudoHeader;
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static uint16_t udp_checksum(const UdpPseudoHeader *pseudoHeader, const uint8_t * hdr, uint32_t size) {
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uint32_t sum = chksum((const uint8_t *)pseudoHeader, sizeof(UdpPseudoHeader)) + chksum(hdr, size);
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while (sum >> 16) {
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sum = (sum & 0xFFFF) + (sum >> 16);
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}
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return sum;
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}
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int parse_udp(const uint8_t *hdr, uint32_t size, PcktHeaderElement *pcktHdrLe, struct EthInterface_ *intf) {
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UdpProps *udpProps = HEADER_FETCH_PROPS(UdpProps, pcktHdrLe);
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FETCH_WORD_H2N_ADVANCE(&udpProps->SourcePort, hdr);
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FETCH_WORD_H2N_ADVANCE(&udpProps->DestinationPort, hdr);
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FETCH_WORD_H2N_ADVANCE(&udpProps->Length, hdr);
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FETCH_WORD_H2N_ADVANCE(&udpProps->Checksum, hdr);
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// common fields...
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udpProps->headerSize = ETH_UDP_HEADER_SIZE;
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udpProps->validityOK = (size == udpProps->Length); // TODO UDP checksum validation!
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udpProps->containedPacketClass = 0;
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return udpProps->validityOK ? 0 : -1;
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}
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void insert_udp_header(uint8_t *hdr, const PcktHeaderElement *headers) {
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uint8_t *hdrBegin = hdr;
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UdpProps *udpProps = (UdpProps *) &headers->props;
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FILL_WORD_H2N_ADVANCE(hdr, udpProps->SourcePort);
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FILL_WORD_H2N_ADVANCE(hdr, udpProps->DestinationPort);
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FILL_WORD_H2N_ADVANCE(hdr, udpProps->Length);
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uint8_t *ChkSumPtr = hdr;
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udpProps->Checksum = 0;
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FILL_WORD_H2N_ADVANCE(hdr, udpProps->Checksum);
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// calculate checksum
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const IPv4Props *ipProps = (IPv4Props *) &headers->prev->props;
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UdpPseudoHeader ph = {ipProps->SourceIPAddr, ipProps->DestIPAddr, 0, ETH_UDP_PACKET_CLASS, htons(udpProps->Length)};
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udpProps->Checksum = udp_checksum(&ph, hdrBegin, udpProps->Length);
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memcpy(ChkSumPtr, &udpProps->Checksum, 2);
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}
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