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/core/internet_checksum.h"
11 #include "quiche/common/quiche_callbacks.h"
12 #include "quiche/common/quiche_endian.h"
13
14 namespace quic {
15 namespace {
16
17 constexpr size_t kIPv6AddressSize = sizeof(in6_addr);
18 constexpr size_t kIPv6HeaderSize = sizeof(ip6_hdr);
19 constexpr size_t kICMPv6HeaderSize = sizeof(icmp6_hdr);
20 constexpr size_t kIPv6MinPacketSize = 1280;
21
22 // Hop limit set to 255 to satisfy:
23 // https://datatracker.ietf.org/doc/html/rfc4861#section-11.2
24 constexpr size_t kIcmpTtl = 255;
25 constexpr size_t kICMPv6BodyMaxSize =
26 kIPv6MinPacketSize - kIPv6HeaderSize - kICMPv6HeaderSize;
27
28 struct ICMPv6Packet {
29 ip6_hdr ip_header;
30 icmp6_hdr icmp_header;
31 uint8_t body[kICMPv6BodyMaxSize];
32 };
33
34 // pseudo header as described in RFC 2460 Section 8.1 (excluding addresses)
35 struct IPv6PseudoHeader {
36 uint32_t payload_size{};
37 uint8_t zeros[3] = {0, 0, 0};
38 uint8_t next_header = IPPROTO_ICMPV6;
39 };
40
41 } // namespace
42
CreateIcmpPacket(in6_addr src,in6_addr dst,const icmp6_hdr & icmp_header,absl::string_view body,quiche::UnretainedCallback<void (absl::string_view)> cb)43 void CreateIcmpPacket(in6_addr src, in6_addr dst, const icmp6_hdr& icmp_header,
44 absl::string_view body,
45 quiche::UnretainedCallback<void(absl::string_view)> cb) {
46 const size_t body_size = std::min(body.size(), kICMPv6BodyMaxSize);
47 const size_t payload_size = kICMPv6HeaderSize + body_size;
48
49 ICMPv6Packet icmp_packet{};
50 // Set version to 6.
51 icmp_packet.ip_header.ip6_vfc = 0x6 << 4;
52 // Set the payload size, protocol and TTL.
53 icmp_packet.ip_header.ip6_plen =
54 quiche::QuicheEndian::HostToNet16(payload_size);
55 icmp_packet.ip_header.ip6_nxt = IPPROTO_ICMPV6;
56 icmp_packet.ip_header.ip6_hops = kIcmpTtl;
57 // Set the source address to the specified self IP.
58 icmp_packet.ip_header.ip6_src = src;
59 icmp_packet.ip_header.ip6_dst = dst;
60
61 icmp_packet.icmp_header = icmp_header;
62 // Per RFC 4443 Section 2.3, set checksum field to 0 prior to computing it
63 icmp_packet.icmp_header.icmp6_cksum = 0;
64
65 IPv6PseudoHeader pseudo_header{};
66 pseudo_header.payload_size = quiche::QuicheEndian::HostToNet32(payload_size);
67
68 InternetChecksum checksum;
69 // Pseudoheader.
70 checksum.Update(icmp_packet.ip_header.ip6_src.s6_addr, kIPv6AddressSize);
71 checksum.Update(icmp_packet.ip_header.ip6_dst.s6_addr, kIPv6AddressSize);
72 checksum.Update(reinterpret_cast<char*>(&pseudo_header),
73 sizeof(pseudo_header));
74 // ICMP header.
75 checksum.Update(reinterpret_cast<const char*>(&icmp_packet.icmp_header),
76 sizeof(icmp_packet.icmp_header));
77 // Body.
78 checksum.Update(body.data(), body_size);
79 icmp_packet.icmp_header.icmp6_cksum = checksum.Value();
80
81 memcpy(icmp_packet.body, body.data(), body_size);
82
83 const char* packet = reinterpret_cast<char*>(&icmp_packet);
84 const size_t packet_size = offsetof(ICMPv6Packet, body) + body_size;
85
86 cb(absl::string_view(packet, packet_size));
87 }
88
89 } // namespace quic
90