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Code Issues Releases Wiki Activity

Fixed bug on ICMP checksum calculation when using timestamp request/replies.

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This commit is contained in:
Matias Fontanini
2013-12-14 13:42:12 -03:00
parent 1cec0f106d
commit 81a947e3b3
2 changed files with 23 additions and 5 deletions
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13
src/icmp.cpp
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@@ -57,10 +57,14 @@ ICMP::ICMP(const uint8_t *buffer, uint32_t total_sz)
buffer += sizeof(icmphdr);
total_sz -= sizeof(icmphdr);
if(type() == TIMESTAMP_REQUEST || type() == TIMESTAMP_REPLY) {
if(total_sz < sizeof(uint32_t) * 3)
throw malformed_packet();
const uint32_t *ptr = reinterpret_cast<const uint32_t*>(buffer);
original_timestamp(*ptr++);
receive_timestamp(*ptr++);
transmit_timestamp(*ptr++);
total_sz -= sizeof(uint32_t) * 3;
buffer += sizeof(uint32_t) * 3;
}
if(total_sz)
inner_pdu(new RawPDU(buffer, total_sz));
@@ -183,17 +187,16 @@ void ICMP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *)
*ptr++ = receive_timestamp();
*ptr++ = transmit_timestamp();
}
// checksum calc
_icmp.check = 0;
uint32_t checksum = Utils::do_checksum(buffer + ICMP::header_size(), buffer + total_sz) +
Utils::do_checksum((uint8_t*)&_icmp, ((uint8_t*)&_icmp) + ICMP::header_size());
memcpy(buffer, &_icmp, sizeof(icmphdr));
uint32_t checksum = Utils::do_checksum(buffer, buffer + total_sz);
while (checksum >> 16)
checksum = (checksum & 0xffff) + (checksum >> 16);
_icmp.check = Endian::host_to_be<uint16_t>(~checksum);
memcpy(buffer, &_icmp, sizeof(icmphdr));
((icmphdr*)buffer)->check = _icmp.check;
}
bool ICMP::matches_response(const uint8_t *ptr, uint32_t total_sz) const {