qt_icmp

1#include "qt_icmp/icmp_packet.hpp"
2
3#include <cstring>
4
5ICMPPacket::ICMPPacket(quint16 id, quint16 sequence) {
6    memset(&icmp_hdr_, 0, sizeof(icmp_hdr_));
7    icmp_hdr_.type = ICMP_ECHO;
8    icmp_hdr_.un.echo.id = id;
9    icmp_hdr_.un.echo.sequence = sequence;
10    icmp_hdr_.checksum = calculateChecksum();
11}
12
13const struct icmphdr* ICMPPacket::header() const {
14    return &icmp_hdr_;
15}
16
17size_t ICMPPacket::size() const {
18    return sizeof(icmp_hdr_);
19}
20
21unsigned short ICMPPacket::calculateChecksum() {
22    unsigned short *buf = reinterpret_cast<unsigned short*>(&icmp_hdr_);
23    unsigned int sum = 0;
24    for (int len = sizeof(icmp_hdr_); len > 1; len -= 2) {
25        sum += *buf++;
26    }
27    if (sizeof(icmp_hdr_) % 2 == 1) {
28        sum += *(reinterpret_cast<unsigned char*>(buf));
29    }
30    sum = (sum >> 16) + (sum & 0xFFFF);
31    sum += (sum >> 16);
32    return static_cast<unsigned short>(~sum);
33}
34