#include <errno.h>

#define min(x,y) ((x)<(y)?(x):(y))

extern const char *side;

#define HANDSHAKE_EXPECT(c, s, clierr, serverr) \

  sret = cret = GNUTLS_E_AGAIN; \

  do \

    { \

      if (cret == GNUTLS_E_AGAIN) \

	{ \

	  side = "client"; \

	  cret = gnutls_handshake (c); \

	  if (cret == GNUTLS_E_INTERRUPTED) cret = GNUTLS_E_AGAIN; \

	} \

      if (sret == GNUTLS_E_AGAIN) \

	{ \

	  side = "server"; \

	  sret = gnutls_handshake (s); \

	  if (sret == GNUTLS_E_INTERRUPTED) sret = GNUTLS_E_AGAIN; \

	} \

    } \

  while ((cret == GNUTLS_E_AGAIN || (cret == 0 && sret == GNUTLS_E_AGAIN)) && (sret == GNUTLS_E_AGAIN || (sret == 0 && cret == GNUTLS_E_AGAIN))); \

  if (cret != clierr || sret != serverr) \

    { \

      fprintf(stderr, "client[%d]: %s\n", cret, gnutls_strerror(cret)); \

      fprintf(stderr, "server[%d]: %s\n", sret, gnutls_strerror(sret)); \

      fail("Handshake failed\n"); \

      exit(1); \

    }

#define HANDSHAKE(c, s) \

  HANDSHAKE_EXPECT(c,s,0,0)

#define HANDSHAKE_DTLS_EXPECT(c, s, clierr, serverr) \

  sret = cret = GNUTLS_E_AGAIN; \

  do \

    { \

      if (cret == GNUTLS_E_LARGE_PACKET) \

	{ \

	  unsigned int mtu = gnutls_dtls_get_mtu(s); \

	  gnutls_dtls_set_mtu(s, mtu/2); \

	} \

      if (cret < 0 && gnutls_error_is_fatal(cret) == 0) \

	{ \

	  side = "client"; \

	  cret = gnutls_handshake (c); \

	} \

      if (sret == GNUTLS_E_LARGE_PACKET) \

	{ \

	  unsigned int mtu = gnutls_dtls_get_mtu(s); \

	  gnutls_dtls_set_mtu(s, mtu/2); \

	} \

      if (sret < 0 && gnutls_error_is_fatal(sret) == 0) \

	{ \

	  side = "server"; \

	  sret = gnutls_handshake (s); \

	} \

    } \

  while (((gnutls_error_is_fatal(cret) == 0 && gnutls_error_is_fatal(sret) == 0)) && (cret < 0 || sret < 0)); \

  if (cret != clierr || sret != serverr) \

    { \

      fprintf(stderr, "client: %s\n", gnutls_strerror(cret)); \

      fprintf(stderr, "server: %s\n", gnutls_strerror(sret)); \

      fail("%s:%d: Handshake failed\n", __func__, __LINE__); \

      exit(1); \

    }

#define HANDSHAKE_DTLS(c, s) \

  HANDSHAKE_DTLS_EXPECT(c,s,0,0)

#define HANDSHAKE(c, s) \

  HANDSHAKE_EXPECT(c,s,0,0)

#define TRANSFER2(c, s, msg, msglen, buf, buflen, retry_send_with_null) \

  side = "client"; \

  ret = record_send_loop (c, msg, msglen, retry_send_with_null); \

  \

  if (ret < 0) fail ("client send error: %s\n", gnutls_strerror (ret)); \

  \

  do \

    { \

      do \

	{ \

	  side = "server"; \

	  ret = gnutls_record_recv (s, buf, buflen); \

	} \

      while(ret == GNUTLS_E_AGAIN); \

      if (ret == 0) \

	fail ("server: didn't receive any data\n"); \

      else if (ret < 0) \

	{ \

	  fail ("server: error: %s\n", gnutls_strerror (ret)); \

	} \

      else \

	{ \

	  transferred += ret; \

	} \

      side = "server"; \

      ns = record_send_loop (server, msg, msglen, retry_send_with_null); \

      if (ns < 0) fail ("server send error: %s\n", gnutls_strerror (ret)); \

      do \

	{ \

	  side = "client"; \

	  ret = gnutls_record_recv (client, buf, buflen); \

	} \

      while(ret == GNUTLS_E_AGAIN); \

      if (ret == 0) \

	{ \

	  fail ("client: Peer has closed the TLS connection\n"); \

	} \

      else if (ret < 0) \

	{ \

	  if (debug) \

	    fputs ("!", stdout); \

	  fail ("client: Error: %s\n", gnutls_strerror (ret)); \

	} \

      else \

	{ \

	  if (msglen != ret || memcmp (buf, msg, msglen) != 0) \

	    { \

	      fail ("client: Transmitted data do not match\n"); \

	    } \

	  /* echo back */ \

	  side = "client"; \

	  ns = record_send_loop (client, buf, msglen, retry_send_with_null); \

	  if (ns < 0) fail ("client send error: %s\n", gnutls_strerror (ret)); \

	  transferred += ret; \

	  if (debug) \

	    fputs (".", stdout); \

	} \

    } \

  while (transferred < 70000)

#define TRANSFER(c, s, msg, msglen, buf, buflen) \

  TRANSFER2(c, s, msg, msglen, buf, buflen, 0); \

  TRANSFER2(c, s, msg, msglen, buf, buflen, 1)

static char to_server[64 * 1024];

static size_t to_server_len = 0;

static char to_client[64 * 1024];

static size_t to_client_len = 0;

#ifdef RANDOMIZE

#define RETURN_RND_EAGAIN(session) \

  static unsigned char rnd = 0; \

  if (rnd++ % 2 == 0) \

    { \

      gnutls_transport_set_errno (session, EAGAIN); \

      return -1; \

    }

#else

#define RETURN_RND_EAGAIN(session)

#endif

#ifndef IGNORE_PUSH

static ssize_t

client_push(gnutls_transport_ptr_t tr, const void *data, size_t len)

{

	size_t newlen;

	RETURN_RND_EAGAIN(tr);

	len = min(len, sizeof(to_server) - to_server_len);

	newlen = to_server_len + len;

	memcpy(to_server + to_server_len, data, len);

	to_server_len = newlen;

#ifdef EAGAIN_DEBUG

	fprintf(stderr, "eagain: pushed %d bytes to server (avail: %d)\n",

		(int) len, (int) to_server_len);

#endif

	return len;

}

#endif

static ssize_t

client_pull(gnutls_transport_ptr_t tr, void *data, size_t len)

{

	RETURN_RND_EAGAIN(tr);

	if (to_client_len == 0) {

#ifdef EAGAIN_DEBUG

		fprintf(stderr,

			"eagain: Not enough data by server (asked for: %d, have: %d)\n",

			(int) len, (int) to_client_len);

#endif

		gnutls_transport_set_errno((gnutls_session_t) tr, EAGAIN);

		return -1;

	}

	len = min(len, to_client_len);

	memcpy(data, to_client, len);

	memmove(to_client, to_client + len, to_client_len - len);

	to_client_len -= len;

#ifdef EAGAIN_DEBUG

	fprintf(stderr, "eagain: pulled %d bytes by client (avail: %d)\n",

		(int) len, (int) to_client_len);

#endif

	return len;

}

static ssize_t

server_pull(gnutls_transport_ptr_t tr, void *data, size_t len)

{

	//success ("server_pull len %d has %d\n", len, to_server_len);

	RETURN_RND_EAGAIN(tr);

	if (to_server_len == 0) {

#ifdef EAGAIN_DEBUG

		fprintf(stderr,

			"eagain: Not enough data by client (asked for: %d, have: %d)\n",

			(int) len, (int) to_server_len);

#endif

		gnutls_transport_set_errno((gnutls_session_t) tr, EAGAIN);

		return -1;

	}

	len = min(len, to_server_len);

#ifdef EAGAIN_DEBUG

	fprintf(stderr, "eagain: pulled %d bytes by server (avail: %d)\n",

		(int) len, (int) to_server_len);

#endif

	memcpy(data, to_server, len);

	memmove(to_server, to_server + len, to_server_len - len);

	to_server_len -= len;

	return len;

}

#ifndef IGNORE_PUSH

static ssize_t

server_push(gnutls_transport_ptr_t tr, const void *data, size_t len)

{

	size_t newlen;

	RETURN_RND_EAGAIN(tr);

//  hexprint (data, len);

	len = min(len, sizeof(to_client) - to_client_len);

	newlen = to_client_len + len;

	memcpy(to_client + to_client_len, data, len);

	to_client_len = newlen;

#ifdef EAGAIN_DEBUG

	fprintf(stderr, "eagain: pushed %d bytes to client (avail: %d)\n",

		(int) len, (int) to_client_len);

#endif

#ifdef SERVER_PUSH_ADD

	SERVER_PUSH_ADD

#endif

	return len;

}

#endif

/* inline is used to avoid a gcc warning if used in mini-eagain */

inline static int server_pull_timeout_func(gnutls_transport_ptr_t ptr,

					   unsigned int ms)

{

	int ret;

	if (to_server_len > 0)

		ret = 1;	/* available data */

	else

		ret = 0;	/* timeout */

#ifdef EAGAIN_DEBUG

	fprintf(stderr,

		"eagain: server_pull_timeout: %d (avail: cli %d, serv %d)\n",

		ret, (int) to_client_len, (int) to_server_len);

#endif

	return ret;

}

inline static int client_pull_timeout_func(gnutls_transport_ptr_t ptr,

					   unsigned int ms)

{

	int ret;

	if (to_client_len > 0)

		ret = 1;

	else

		ret = 0;

#ifdef EAGAIN_DEBUG

	fprintf(stderr,

		"eagain: client_pull_timeout: %d (avail: cli %d, serv %d)\n",

		ret, (int) to_client_len, (int) to_server_len);

#endif

	return ret;

}

inline static void reset_buffers(void)

{

	to_server_len = 0;

	to_client_len = 0;

}

inline static int record_send_loop(gnutls_session_t session,

				   const void *data, size_t sizeofdata,

				   int use_null_on_retry)

{

	int ret;

	const void *retry_data;

	size_t retry_sizeofdata;

	if (use_null_on_retry) {

		retry_data = 0;

		retry_sizeofdata = 0;

	} else {

		retry_data = data;

		retry_sizeofdata = sizeofdata;

	}

	ret = gnutls_record_send(session, data, sizeofdata);

	while (ret == GNUTLS_E_AGAIN) {

		ret =

		    gnutls_record_send(session, retry_data,

					retry_sizeofdata);

	}

	return ret;

}