/* Copyright (c) 2014, Google Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

#if !defined(_POSIX_C_SOURCE)
#define _POSIX_C_SOURCE 201410L
#endif

#include <openssl/base.h>

#if !defined(OPENSSL_WINDOWS)
#include <arpa/inet.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
#else
#define WIN32_LEAN_AND_MEAN
#include <io.h>
#include <WinSock2.h>
#include <WS2tcpip.h>
#endif

#include <openssl/bio.h>
#include <openssl/crypto.h>
#include <openssl/err.h>

#define MIN(a, b) ((a < b) ? a : b)

#if !defined(OPENSSL_WINDOWS)
static int closesocket(int sock) {
  return close(sock);
}

static void print_socket_error(const char *func) {
  perror(func);
}
#else
static void print_socket_error(const char *func) {
  fprintf(stderr, "%s: %d\n", func, WSAGetLastError());
}
#endif

static int test_socket_connect(void) {
  int listening_sock = socket(AF_INET, SOCK_STREAM, 0);
  int sock;
  struct sockaddr_in sin;
  socklen_t sockaddr_len = sizeof(sin);
  static const char kTestMessage[] = "test";
  char hostname[80], buf[5];
  BIO *bio;

  memset(&sin, 0, sizeof(sin));
  sin.sin_family = AF_INET;
  if (!inet_pton(AF_INET, "127.0.0.1", &sin.sin_addr)) {
    print_socket_error("inet_pton");
    return 0;
  }

  if (bind(listening_sock, (struct sockaddr *)&sin, sizeof(sin)) != 0) {
    print_socket_error("bind");
    return 0;
  }

  if (listen(listening_sock, 1)) {
    print_socket_error("listen");
    return 0;
  }

  if (getsockname(listening_sock, (struct sockaddr *)&sin, &sockaddr_len) ||
      sockaddr_len != sizeof(sin)) {
    print_socket_error("getsockname");
    return 0;
  }

  BIO_snprintf(hostname, sizeof(hostname), "%s:%d", "127.0.0.1",
               ntohs(sin.sin_port));
  bio = BIO_new_connect(hostname);
  if (!bio) {
    fprintf(stderr, "BIO_new_connect failed.\n");
    return 0;
  }

  if (BIO_write(bio, kTestMessage, sizeof(kTestMessage)) !=
      sizeof(kTestMessage)) {
    fprintf(stderr, "BIO_write failed.\n");
    BIO_print_errors_fp(stderr);
    return 0;
  }

  sock = accept(listening_sock, (struct sockaddr *) &sin, &sockaddr_len);
  if (sock < 0) {
    print_socket_error("accept");
    return 0;
  }

  if (recv(sock, buf, sizeof(buf), 0) != sizeof(kTestMessage)) {
    print_socket_error("read");
    return 0;
  }

  if (memcmp(buf, kTestMessage, sizeof(kTestMessage))) {
    return 0;
  }

  closesocket(sock);
  closesocket(listening_sock);
  BIO_free(bio);

  return 1;
}


/* bio_read_zero_copy_wrapper is a wrapper around the zero-copy APIs to make
 * testing easier. */
static size_t bio_read_zero_copy_wrapper(BIO *bio, uint8_t *data, size_t len) {
  uint8_t *read_buf;
  size_t read_buf_offset;
  size_t available_bytes;
  size_t len_read = 0;

  do {
    if (!BIO_zero_copy_get_read_buf(bio, &read_buf, &read_buf_offset,
                                    &available_bytes)) {
      return 0;
    }

    available_bytes = MIN(available_bytes, len - len_read);
    memmove(data + len_read, read_buf + read_buf_offset, available_bytes);

    BIO_zero_copy_get_read_buf_done(bio, available_bytes);

    len_read += available_bytes;
  } while (len - len_read > 0 && available_bytes > 0);

  return len_read;
}

/* bio_write_zero_copy_wrapper is a wrapper around the zero-copy APIs to make
 * testing easier. */
static size_t bio_write_zero_copy_wrapper(BIO *bio, const uint8_t *data,
                                          size_t len) {
  uint8_t *write_buf;
  size_t write_buf_offset;
  size_t available_bytes;
  size_t len_written = 0;

  do {
    if (!BIO_zero_copy_get_write_buf(bio, &write_buf, &write_buf_offset,
                                     &available_bytes)) {
      return 0;
    }

    available_bytes = MIN(available_bytes, len - len_written);
    memmove(write_buf + write_buf_offset, data + len_written, available_bytes);

    BIO_zero_copy_get_write_buf_done(bio, available_bytes);

    len_written += available_bytes;
  } while (len - len_written > 0 && available_bytes > 0);

  return len_written;
}

static int test_zero_copy_bio_pairs(void) {
  /* Test read and write, especially triggering the ring buffer wrap-around.*/
  BIO* bio1;
  BIO* bio2;
  size_t i, j;
  uint8_t bio1_application_send_buffer[1024];
  uint8_t bio2_application_recv_buffer[1024];
  size_t total_read = 0;
  size_t total_write = 0;
  uint8_t* write_buf;
  size_t write_buf_offset;
  size_t available_bytes;
  size_t bytes_left;

  const size_t kLengths[] = {254, 255, 256, 257, 510, 511, 512, 513};

  /* These trigger ring buffer wrap around. */
  const size_t kPartialLengths[] = {0, 1, 2, 3, 128, 255, 256, 257, 511, 512};

  static const size_t kBufferSize = 512;

  srand(1);
  for (i = 0; i < sizeof(bio1_application_send_buffer); i++) {
    bio1_application_send_buffer[i] = rand() & 255;
  }

  /* Transfer bytes from bio1_application_send_buffer to
   * bio2_application_recv_buffer in various ways. */
  for (i = 0; i < sizeof(kLengths) / sizeof(kLengths[0]); i++) {
    for (j = 0; j < sizeof(kPartialLengths) / sizeof(kPartialLengths[0]); j++) {
      total_write = 0;
      total_read = 0;

      BIO_new_bio_pair(&bio1, kBufferSize, &bio2, kBufferSize);

      total_write += bio_write_zero_copy_wrapper(
          bio1, bio1_application_send_buffer, kLengths[i]);

      /* This tests interleaved read/write calls. Do a read between zero copy
       * write calls. */
      if (!BIO_zero_copy_get_write_buf(bio1, &write_buf, &write_buf_offset,
                                       &available_bytes)) {
        return 0;
      }

      /* Free kPartialLengths[j] bytes in the beginning of bio1 write buffer.
       * This enables ring buffer wrap around for the next write. */
      total_read += BIO_read(bio2, bio2_application_recv_buffer + total_read,
                             kPartialLengths[j]);

      size_t interleaved_write_len = MIN(kPartialLengths[j], available_bytes);

      /* Write the data for the interleaved write call. If the buffer becomes
       * empty after a read, the write offset is normally set to 0. Check that
       * this does not happen for interleaved read/write and that
       * |write_buf_offset| is still valid. */
      memcpy(write_buf + write_buf_offset,
             bio1_application_send_buffer + total_write, interleaved_write_len);
      if (BIO_zero_copy_get_write_buf_done(bio1, interleaved_write_len)) {
        total_write += interleaved_write_len;
      }

      /* Do another write in case |write_buf_offset| was wrapped */
      total_write += bio_write_zero_copy_wrapper(
          bio1, bio1_application_send_buffer + total_write,
          kPartialLengths[j] - interleaved_write_len);

      /* Drain the rest. */
      bytes_left = BIO_pending(bio2);
      total_read += bio_read_zero_copy_wrapper(
          bio2, bio2_application_recv_buffer + total_read, bytes_left);

      BIO_free(bio1);
      BIO_free(bio2);

      if (total_read != total_write) {
        fprintf(stderr, "Lengths not equal in round (%u, %u)\n", (unsigned)i,
                (unsigned)j);
        return 0;
      }
      if (total_read > kLengths[i] + kPartialLengths[j]) {
        fprintf(stderr, "Bad lengths in round (%u, %u)\n", (unsigned)i,
                (unsigned)j);
        return 0;
      }
      if (memcmp(bio1_application_send_buffer, bio2_application_recv_buffer,
                 total_read) != 0) {
        fprintf(stderr, "Buffers not equal in round (%u, %u)\n", (unsigned)i,
                (unsigned)j);
        return 0;
      }
    }
  }

  return 1;
}

static int test_printf(void) {
  /* Test a short output, a very long one, and various sizes around
   * 256 (the size of the buffer) to ensure edge cases are correct. */
  static const size_t kLengths[] = { 5, 250, 251, 252, 253, 254, 1023 };
  BIO *bio;
  char string[1024];
  int ret;
  const uint8_t *contents;
  size_t i, len;

  bio = BIO_new(BIO_s_mem());
  if (!bio) {
    fprintf(stderr, "BIO_new failed\n");
    return 0;
  }

  for (i = 0; i < sizeof(kLengths) / sizeof(kLengths[0]); i++) {
    if (kLengths[i] >= sizeof(string)) {
      fprintf(stderr, "Bad test string length\n");
      return 0;
    }
    memset(string, 'a', sizeof(string));
    string[kLengths[i]] = '\0';

    ret = BIO_printf(bio, "test %s", string);
    if (ret != 5 + kLengths[i]) {
      fprintf(stderr, "BIO_printf failed: %d\n", ret);
      return 0;
    }
    if (!BIO_mem_contents(bio, &contents, &len)) {
      fprintf(stderr, "BIO_mem_contents failed\n");
      return 0;
    }
    if (len != 5 + kLengths[i] ||
        strncmp((const char *)contents, "test ", 5) != 0 ||
        strncmp((const char *)contents + 5, string, kLengths[i]) != 0) {
      fprintf(stderr, "Contents did not match: %.*s\n", (int)len, contents);
      return 0;
    }

    if (!BIO_reset(bio)) {
      fprintf(stderr, "BIO_reset failed\n");
      return 0;
    }
  }

  BIO_free(bio);
  return 1;
}

int main(void) {
#if defined(OPENSSL_WINDOWS)
  WSADATA wsa_data;
  WORD wsa_version;
  int wsa_err;
#endif

  CRYPTO_library_init();
  ERR_load_crypto_strings();

#if defined(OPENSSL_WINDOWS)
  /* Initialize Winsock. */
  wsa_version = MAKEWORD(2, 2);
  wsa_err = WSAStartup(wsa_version, &wsa_data);
  if (wsa_err != 0) {
    fprintf(stderr, "WSAStartup failed: %d\n", wsa_err);
    return 1;
  }
  if (wsa_data.wVersion != wsa_version) {
    fprintf(stderr, "Didn't get expected version: %x\n", wsa_data.wVersion);
    return 1;
  }
#endif

  if (!test_socket_connect()) {
    return 1;
  }

  if (!test_printf()) {
    return 1;
  }

  if (!test_zero_copy_bio_pairs()) {
    return 1;
  }

  printf("PASS\n");
  return 0;
}