text: /*
   * nghttp2 - HTTP/2 C Library
   *
   * Copyright (c) 2021 Tatsuhiro Tsujikawa
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  #include "shrpx_quic.h"
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <netdb.h>
  #include <netinet/udp.h>
  
  #include <array>
  #include <chrono>
  
  #include <ngtcp2/ngtcp2_crypto.h>
  
  #include <nghttp3/nghttp3.h>
  
  #include <openssl/rand.h>
  
  #include "shrpx_config.h"
  #include "shrpx_log.h"
  #include "util.h"
  #include "xsi_strerror.h"
  
  bool operator==(const ngtcp2_cid &lhs, const ngtcp2_cid &rhs) {
    return ngtcp2_cid_eq(&lhs, &rhs);
  }
  
  namespace shrpx {
  
  ngtcp2_tstamp quic_timestamp() {
    return std::chrono::duration_cast<std::chrono::nanoseconds>(
               std::chrono::steady_clock::now().time_since_epoch())
        .count();
  }
  
  int quic_send_packet(const UpstreamAddr *faddr, const sockaddr *remote_sa,
                       size_t remote_salen, const sockaddr *local_sa,
                       size_t local_salen, const ngtcp2_pkt_info &pi,
                       const uint8_t *data, size_t datalen, size_t gso_size) {
    iovec msg_iov = {const_cast<uint8_t *>(data), datalen};
    msghdr msg{};
    msg.msg_name = const_cast<sockaddr *>(remote_sa);
    msg.msg_namelen = remote_salen;
    msg.msg_iov = &msg_iov;
    msg.msg_iovlen = 1;
  
    uint8_t msg_ctrl[
  #ifdef UDP_SEGMENT
        CMSG_SPACE(sizeof(uint16_t)) +
  #endif // UDP_SEGMENT
        CMSG_SPACE(sizeof(in6_pktinfo))];
  
    memset(msg_ctrl, 0, sizeof(msg_ctrl));
  
    msg.msg_control = msg_ctrl;
    msg.msg_controllen = sizeof(msg_ctrl);
  
    size_t controllen = 0;
  
    auto cm = CMSG_FIRSTHDR(&msg);
  
    switch (local_sa->sa_family) {
    case AF_INET: {
      controllen += CMSG_SPACE(sizeof(in_pktinfo));
      cm->cmsg_level = IPPROTO_IP;
      cm->cmsg_type = IP_PKTINFO;
      cm->cmsg_len = CMSG_LEN(sizeof(in_pktinfo));
      auto pktinfo = reinterpret_cast<in_pktinfo *>(CMSG_DATA(cm));
      memset(pktinfo, 0, sizeof(in_pktinfo));
      auto addrin =
          reinterpret_cast<sockaddr_in *>(const_cast<sockaddr *>(local_sa));
      pktinfo->ipi_spec_dst = addrin->sin_addr;
      break;
    }
    case AF_INET6: {
      controllen += CMSG_SPACE(sizeof(in6_pktinfo));
      cm->cmsg_level = IPPROTO_IPV6;
      cm->cmsg_type = IPV6_PKTINFO;
      cm->cmsg_len = CMSG_LEN(sizeof(in6_pktinfo));
      auto pktinfo = reinterpret_cast<in6_pktinfo *>(CMSG_DATA(cm));
      memset(pktinfo, 0, sizeof(in6_pktinfo));
      auto addrin =
          reinterpret_cast<sockaddr_in6 *>(const_cast<sockaddr *>(local_sa));
      pktinfo->ipi6_addr = addrin->sin6_addr;
      break;
    }
    default:
      assert(0);
    }
  
  #ifdef UDP_SEGMENT
    if (gso_size && datalen > gso_size) {
      controllen += CMSG_SPACE(sizeof(uint16_t));
      cm = CMSG_NXTHDR(&msg, cm);
      cm->cmsg_level = SOL_UDP;
      cm->cmsg_type = UDP_SEGMENT;
      cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));
      *(reinterpret_cast<uint16_t *>(CMSG_DATA(cm))) = gso_size;
    }
  #endif // UDP_SEGMENT
  
    msg.msg_controllen = controllen;
  
    util::fd_set_send_ecn(faddr->fd, local_sa->sa_family, pi.ecn);
  
    ssize_t nwrite;
  
    do {
      nwrite = sendmsg(faddr->fd, &msg, 0);
    } while (nwrite == -1 && errno == EINTR);
  
    if (nwrite == -1) {
      if (LOG_ENABLED(INFO)) {
        auto error = errno;
        LOG(INFO) << "sendmsg failed: errno=" << error;
      }
  
      return -errno;
    }
  
    if (LOG_ENABLED(INFO)) {
      LOG(INFO) << "QUIC sent packet: local="
                << util::to_numeric_addr(local_sa, local_salen)
                << " remote=" << util::to_numeric_addr(remote_sa, remote_salen)
                << " ecn=" << log::hex << pi.ecn << log::dec << " " << nwrite
                << " bytes";
    }
  
    return 0;
  }
  
  int generate_quic_retry_connection_id(ngtcp2_cid &cid, size_t cidlen,
                                        const uint8_t *server_id, uint8_t km_id,
                                        const uint8_t *key) {
    assert(cidlen == SHRPX_QUIC_SCIDLEN);
  
    if (RAND_bytes(cid.data, cidlen) != 1) {
      return -1;
    }
  
    cid.datalen = cidlen;
  
    cid.data[0] = (cid.data[0] & 0x3f) | km_id;
  
    auto p = cid.data + SHRPX_QUIC_CID_PREFIX_OFFSET;
  
    std::copy_n(server_id, SHRPX_QUIC_SERVER_IDLEN, p);
  
    return encrypt_quic_connection_id(p, p, key);
  }
  
  int generate_quic_connection_id(ngtcp2_cid &cid, size_t cidlen,
                                  const uint8_t *cid_prefix, uint8_t km_id,
                                  const uint8_t *key) {
    assert(cidlen == SHRPX_QUIC_SCIDLEN);
  
    if (RAND_bytes(cid.data, cidlen) != 1) {
      return -1;
    }
  
    cid.datalen = cidlen;
  
    cid.data[0] = (cid.data[0] & 0x3f) | km_id;
  
    auto p = cid.data + SHRPX_QUIC_CID_PREFIX_OFFSET;
  
    std::copy_n(cid_prefix, SHRPX_QUIC_CID_PREFIXLEN, p);
  
    return encrypt_quic_connection_id(p, p, key);
  }
  
  int encrypt_quic_connection_id(uint8_t *dest, const uint8_t *src,
                                 const uint8_t *key) {
    auto ctx = EVP_CIPHER_CTX_new();
    auto d = defer(EVP_CIPHER_CTX_free, ctx);
  
    if (!EVP_EncryptInit_ex(ctx, EVP_aes_128_ecb(), nullptr, key, nullptr)) {
      return -1;
    }
  
    EVP_CIPHER_CTX_set_padding(ctx, 0);
  
    int len;
  
    if (!EVP_EncryptUpdate(ctx, dest, &len, src, SHRPX_QUIC_DECRYPTED_DCIDLEN) ||
        !EVP_EncryptFinal_ex(ctx, dest + len, &len)) {
      return -1;
    }
  
    return 0;
  }
  
  int decrypt_quic_connection_id(uint8_t *dest, const uint8_t *src,
                                 const uint8_t *key) {
    auto ctx = EVP_CIPHER_CTX_new();
    auto d = defer(EVP_CIPHER_CTX_free, ctx);
  
    if (!EVP_DecryptInit_ex(ctx, EVP_aes_128_ecb(), nullptr, key, nullptr)) {
      return -1;
    }
  
    EVP_CIPHER_CTX_set_padding(ctx, 0);
  
    int len;
  
    if (!EVP_DecryptUpdate(ctx, dest, &len, src, SHRPX_QUIC_DECRYPTED_DCIDLEN) ||
        !EVP_DecryptFinal_ex(ctx, dest + len, &len)) {
      return -1;
    }
  
    return 0;
  }
  
  int generate_quic_hashed_connection_id(ngtcp2_cid &dest,
                                         const Address &remote_addr,
                                         const Address &local_addr,
                                         const ngtcp2_cid &cid) {
    auto ctx = EVP_MD_CTX_new();
    auto d = defer(EVP_MD_CTX_free, ctx);
  
    std::array<uint8_t, 32> h;
    unsigned int hlen = EVP_MD_size(EVP_sha256());
  
    if (!EVP_DigestInit_ex(ctx, EVP_sha256(), nullptr) ||
        !EVP_DigestUpdate(ctx, &remote_addr.su.sa, remote_addr.len) ||
        !EVP_DigestUpdate(ctx, &local_addr.su.sa, local_addr.len) ||
        !EVP_DigestUpdate(ctx, cid.data, cid.datalen) ||
        !EVP_DigestFinal_ex(ctx, h.data(), &hlen)) {
      return -1;
    }
  
    assert(hlen == h.size());
  
    std::copy_n(std::begin(h), sizeof(dest.data), std::begin(dest.data));
    dest.datalen = sizeof(dest.data);
  
    return 0;
  }
  
  int generate_quic_stateless_reset_token(uint8_t *token, const ngtcp2_cid &cid,
                                          const uint8_t *secret,
                                          size_t secretlen) {
    if (ngtcp2_crypto_generate_stateless_reset_token(token, secret, secretlen,
                                                     &cid) != 0) {
      return -1;
    }
  
    return 0;
  }
  
  int generate_retry_token(uint8_t *token, size_t &tokenlen, uint32_t version,
                           const sockaddr *sa, socklen_t salen,
                           const ngtcp2_cid &retry_scid, const ngtcp2_cid &odcid,
                           const uint8_t *secret, size_t secretlen) {
    auto t = std::chrono::duration_cast<std::chrono::nanoseconds>(
                 std::chrono::system_clock::now().time_since_epoch())
                 .count();
  
    auto stokenlen = ngtcp2_crypto_generate_retry_token(
        token, secret, secretlen, version, sa, salen, &retry_scid, &odcid, t);
    if (stokenlen < 0) {
      return -1;
    }
  
    tokenlen = stokenlen;
  
    return 0;
  }
  
  int verify_retry_token(ngtcp2_cid &odcid, const uint8_t *token, size_t tokenlen,
                         uint32_t version, const ngtcp2_cid &dcid,
                         const sockaddr *sa, socklen_t salen,
                         const uint8_t *secret, size_t secretlen) {
  
    auto t = std::chrono::duration_cast<std::chrono::nanoseconds>(
                 std::chrono::system_clock::now().time_since_epoch())
                 .count();
  
    if (ngtcp2_crypto_verify_retry_token(&odcid, token, tokenlen, secret,
                                         secretlen, version, sa, salen, &dcid,
                                         10 * NGTCP2_SECONDS, t) != 0) {
      return -1;
    }
  
    return 0;
  }
  
  int generate_token(uint8_t *token, size_t &tokenlen, const sockaddr *sa,
                     size_t salen, const uint8_t *secret, size_t secretlen) {
    auto t = std::chrono::duration_cast<std::chrono::nanoseconds>(
                 std::chrono::system_clock::now().time_since_epoch())
                 .count();
  
    auto stokenlen = ngtcp2_crypto_generate_regular_token(
        token, secret, secretlen, sa, salen, t);
    if (stokenlen < 0) {
      return -1;
    }
  
    tokenlen = stokenlen;
  
    return 0;
  }
  
  int verify_token(const uint8_t *token, size_t tokenlen, const sockaddr *sa,
                   socklen_t salen, const uint8_t *secret, size_t secretlen) {
    auto t = std::chrono::duration_cast<std::chrono::nanoseconds>(
                 std::chrono::system_clock::now().time_since_epoch())
                 .count();
  
    if (ngtcp2_crypto_verify_regular_token(token, tokenlen, secret, secretlen, sa,
                                           salen, 3600 * NGTCP2_SECONDS,
                                           t) != 0) {
      return -1;
    }
  
    return 0;
  }
  
  int generate_quic_connection_id_encryption_key(uint8_t *key, size_t keylen,
                                                 const uint8_t *secret,
                                                 size_t secretlen,
                                                 const uint8_t *salt,
                                                 size_t saltlen) {
    constexpr uint8_t info[] = "connection id encryption key";
    ngtcp2_crypto_md sha256;
    ngtcp2_crypto_md_init(
        &sha256, reinterpret_cast<void *>(const_cast<EVP_MD *>(EVP_sha256())));
  
    if (ngtcp2_crypto_hkdf(key, keylen, &sha256, secret, secretlen, salt, saltlen,
                           info, str_size(info)) != 0) {
      return -1;
    }
  
    return 0;
  }
  
  const QUICKeyingMaterial *
  select_quic_keying_material(const QUICKeyingMaterials &qkms,
                              const uint8_t *cid) {
    for (auto &qkm : qkms.keying_materials) {
      if (((*cid) & 0xc0) == qkm.id) {
        return &qkm;
      }
    }
  
    return &qkms.keying_materials.front();
  }
  
  } // namespace shrpx
  