| 660 | } |
| 661 | |
| 662 | static bool ParseDnsPacket(const uint8_t* data, uint32_t size, RawDnsPacket* packet) |
| 663 | { |
| 664 | packet->m_IsResponse = false; |
| 665 | packet->m_Questions.clear(); |
| 666 | packet->m_Records.clear(); |
| 667 | |
| 668 | if (size < 12) |
| 669 | return false; |
| 670 | |
| 671 | uint32_t offset = 0; |
| 672 | uint16_t id = 0; |
| 673 | uint16_t flags = 0; |
| 674 | uint16_t qdcount = 0; |
| 675 | uint16_t ancount = 0; |
| 676 | uint16_t nscount = 0; |
| 677 | uint16_t arcount = 0; |
| 678 | if (!ReadU16(data, size, &offset, &id) |
| 679 | || !ReadU16(data, size, &offset, &flags) |
| 680 | || !ReadU16(data, size, &offset, &qdcount) |
| 681 | || !ReadU16(data, size, &offset, &ancount) |
| 682 | || !ReadU16(data, size, &offset, &nscount) |
| 683 | || !ReadU16(data, size, &offset, &arcount)) |
| 684 | { |
| 685 | return false; |
| 686 | } |
| 687 | |
| 688 | packet->m_IsResponse = (flags & DNS_FLAG_RESPONSE) != 0; |
| 689 | for (uint16_t i = 0; i < qdcount; ++i) |
| 690 | { |
| 691 | RawDnsQuestion question; |
| 692 | if (!ReadName(data, size, &offset, &question.m_Name) |
| 693 | || !ReadU16(data, size, &offset, &question.m_Type) |
| 694 | || !ReadU16(data, size, &offset, &question.m_Class)) |
| 695 | { |
| 696 | return false; |
| 697 | } |
| 698 | packet->m_Questions.push_back(question); |
| 699 | } |
| 700 | |
| 701 | const uint32_t records = (uint32_t) ancount + (uint32_t) nscount + (uint32_t) arcount; |
| 702 | for (uint32_t i = 0; i < records; ++i) |
| 703 | { |
| 704 | RawDnsRecord record; |
| 705 | if (!ReadName(data, size, &offset, &record.m_Name) |
| 706 | || !ReadU16(data, size, &offset, &record.m_Type) |
| 707 | || !ReadU16(data, size, &offset, &record.m_Class) |
| 708 | || !ReadU32(data, size, &offset, &record.m_Ttl) |
| 709 | || !ReadU16(data, size, &offset, &record.m_Rdlength)) |
| 710 | { |
| 711 | return false; |
| 712 | } |
| 713 | |
| 714 | if (offset + record.m_Rdlength > size) |
| 715 | return false; |
| 716 | |
| 717 | const uint32_t rdata_offset = offset; |
| 718 | switch (record.m_Type) |
| 719 | { |