1 // Copyright (c) 2019 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "quiche/quic/qbone/platform/icmp_packet.h"
6
7 #include <netinet/ip6.h>
8
9 #include "absl/strings/string_view.h"
10 #include "quiche/quic/qbone/platform/internet_checksum.h"
11 #include "quiche/common/quiche_endian.h"
12
13 namespace quic {
14 namespace {
15
16 constexpr size_t kIPv6AddressSize = sizeof(in6_addr);
17 constexpr size_t kIPv6HeaderSize = sizeof(ip6_hdr);
18 constexpr size_t kICMPv6HeaderSize = sizeof(icmp6_hdr);
19 constexpr size_t kIPv6MinPacketSize = 1280;
20
21 // Hop limit set to 255 to satisfy:
22 // https://datatracker.ietf.org/doc/html/rfc4861#section-11.2
23 constexpr size_t kIcmpTtl = 255;
24 constexpr size_t kICMPv6BodyMaxSize =
25 kIPv6MinPacketSize - kIPv6HeaderSize - kICMPv6HeaderSize;
26
27 struct ICMPv6Packet {
28 ip6_hdr ip_header;
29 icmp6_hdr icmp_header;
30 uint8_t body[kICMPv6BodyMaxSize];
31 };
32
33 // pseudo header as described in RFC 2460 Section 8.1 (excluding addresses)
34 struct IPv6PseudoHeader {
35 uint32_t payload_size{};
36 uint8_t zeros[3] = {0, 0, 0};
37 uint8_t next_header = IPPROTO_ICMPV6;
38 };
39
40 } // namespace
41
CreateIcmpPacket(in6_addr src,in6_addr dst,const icmp6_hdr & icmp_header,absl::string_view body,const std::function<void (absl::string_view)> & cb)42 void CreateIcmpPacket(in6_addr src, in6_addr dst, const icmp6_hdr& icmp_header,
43 absl::string_view body,
44 const std::function<void(absl::string_view)>& cb) {
45 const size_t body_size = std::min(body.size(), kICMPv6BodyMaxSize);
46 const size_t payload_size = kICMPv6HeaderSize + body_size;
47
48 ICMPv6Packet icmp_packet{};
49 // Set version to 6.
50 icmp_packet.ip_header.ip6_vfc = 0x6 << 4;
51 // Set the payload size, protocol and TTL.
52 icmp_packet.ip_header.ip6_plen =
53 quiche::QuicheEndian::HostToNet16(payload_size);
54 icmp_packet.ip_header.ip6_nxt = IPPROTO_ICMPV6;
55 icmp_packet.ip_header.ip6_hops = kIcmpTtl;
56 // Set the source address to the specified self IP.
57 icmp_packet.ip_header.ip6_src = src;
58 icmp_packet.ip_header.ip6_dst = dst;
59
60 icmp_packet.icmp_header = icmp_header;
61 // Per RFC 4443 Section 2.3, set checksum field to 0 prior to computing it
62 icmp_packet.icmp_header.icmp6_cksum = 0;
63
64 IPv6PseudoHeader pseudo_header{};
65 pseudo_header.payload_size = quiche::QuicheEndian::HostToNet32(payload_size);
66
67 InternetChecksum checksum;
68 // Pseudoheader.
69 checksum.Update(icmp_packet.ip_header.ip6_src.s6_addr, kIPv6AddressSize);
70 checksum.Update(icmp_packet.ip_header.ip6_dst.s6_addr, kIPv6AddressSize);
71 checksum.Update(reinterpret_cast<char*>(&pseudo_header),
72 sizeof(pseudo_header));
73 // ICMP header.
74 checksum.Update(reinterpret_cast<const char*>(&icmp_packet.icmp_header),
75 sizeof(icmp_packet.icmp_header));
76 // Body.
77 checksum.Update(body.data(), body_size);
78 icmp_packet.icmp_header.icmp6_cksum = checksum.Value();
79
80 memcpy(icmp_packet.body, body.data(), body_size);
81
82 const char* packet = reinterpret_cast<char*>(&icmp_packet);
83 const size_t packet_size = offsetof(ICMPv6Packet, body) + body_size;
84
85 cb(absl::string_view(packet, packet_size));
86 }
87
88 } // namespace quic
89