#include "network_backends.h"

#ifdef USE_OPENSSL
#include <sys/types.h>
#include "sys-socket.h"
#include <sys/stat.h>
#include <sys/time.h>
#ifndef _WIN32
#include <sys/resource.h>

#include <netinet/in.h>
#include <netinet/tcp.h>
#include <unistd.h>
#include <netdb.h>
#else
#include <sys/types.h>
#endif

#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

#include "network.h"
#include "fdevent.h"
#include "log.h"
#include "stat_cache.h"

# include <openssl/ssl.h>
# include <openssl/err.h>

NETWORK_BACKEND_READ(openssl) {
	buffer *b;
	off_t len;
	int read_something = 0;
	off_t max_read = 256 * 1024;
	off_t start_bytes_in = cq->bytes_in;
	network_status_t res;
	int toread, read_offset;

	UNUSED(srv);
	UNUSED(con);

	/* use a chunk-size of 4k, append to last buffer if it has >= 1kb free */
#define TOREAD 4096

	do {
		int oerrno;

		b = (cq->last) ? cq->last->mem : NULL;

		if (NULL == b || b->size - b->used < 1024) {
			b = chunkqueue_get_append_buffer(cq);
			buffer_prepare_copy(b, TOREAD+1);
		}

		read_offset = (b->used == 0) ? 0 : b->used - 1;
		toread = b->size - 1 - read_offset;

		ERR_clear_error();
		len = SSL_read(sock->ssl, b->ptr + read_offset, toread);

		/**
		 * man SSL_read:
		 *
		 * >0   is success
		 * 0    is connection close
		 * <0   is error 
		 */
		if (len <= 0) {
			int r, ssl_err;

			oerrno = errno; /* store the errno for SSL_ERROR_SYSCALL */
			chunkqueue_remove_empty_last_chunk(cq);

			switch ((r = SSL_get_error(sock->ssl, len))) {
			case SSL_ERROR_WANT_READ:
			case SSL_ERROR_WANT_WRITE:
				return read_something ? NETWORK_STATUS_SUCCESS : NETWORK_STATUS_WAIT_FOR_EVENT;
			case SSL_ERROR_SYSCALL:
				/**
				 * man SSL_get_error()
				 *
				 * SSL_ERROR_SYSCALL
				 *   Some I/O error occurred.  The OpenSSL error queue may contain more
				 *   information on the error.  If the error queue is empty (i.e.
				 *   ERR_get_error() returns 0), ret can be used to find out more about
				 *   the error: If ret == 0, an EOF was observed that violates the
				 *   protocol.  If ret == -1, the underlying BIO reported an I/O error
				 *   (for socket I/O on Unix systems, consult errno for details).
				 *
				 */
				while((ssl_err = ERR_get_error())) {
					/* get all errors from the error-queue */
					ERROR("ssl-errors: %s", ERR_error_string(ssl_err, NULL));
				}

				if (len == 0) {
					return NETWORK_STATUS_CONNECTION_CLOSE;
				} else {
					switch(oerrno) {
					case EPIPE:
					case ECONNRESET:
						return NETWORK_STATUS_CONNECTION_CLOSE;
					default:
						ERROR("last-errno: (%d) %s", oerrno, strerror(oerrno));
						break;
					}
				}

				return NETWORK_STATUS_FATAL_ERROR;
			case SSL_ERROR_ZERO_RETURN:
				if (len == 0) {
					/* clean shutdown on the remote side */
					return NETWORK_STATUS_CONNECTION_CLOSE;
				}
				/* fall through otherwise */
			default:
				res = NETWORK_STATUS_CONNECTION_CLOSE;
				while((ssl_err = ERR_get_error())) {
					switch (ERR_GET_REASON(ssl_err)) {
					case SSL_R_SSL_HANDSHAKE_FAILURE:
					case SSL_R_TLSV1_ALERT_UNKNOWN_CA:
					case SSL_R_SSLV3_ALERT_CERTIFICATE_UNKNOWN:
					case SSL_R_SSLV3_ALERT_BAD_CERTIFICATE:
						if (!con->conf.log_ssl_noise) continue;
						break;
					default:
						res = NETWORK_STATUS_FATAL_ERROR;
						break;
					}
					/* get all errors from the error-queue */
					ERROR("ssl-errors: %s", ERR_error_string(ssl_err, NULL));
				}

				return res;
			}
		} else {
			if (b->used > 0) b->used--;
			b->used += len;
			b->ptr[b->used++] = '\0';

			read_something = 1;
			cq->bytes_in += len;
		}

		if (cq->bytes_in - start_bytes_in > max_read) break;
	} while (len == toread);

	return NETWORK_STATUS_SUCCESS;
}


NETWORK_BACKEND_WRITE(openssl) {
	int ssl_r;
	chunk *c;

	/* this is a 64k sendbuffer
	 *
	 * it has to stay at the same location all the time to satisfy the needs
	 * of SSL_write to pass the SAME parameter in case of a _WANT_WRITE
	 *
	 * the buffer is allocated once, is NOT realloced and is NOT freed at shutdown
	 * -> we expect a 64k block to 'leak' in valgrind
	 *
	 *
	 * In reality we would like to use mmap() but we don't have a guarantee that
	 * we get the same mmap() address for each call. On openbsd the mmap() address
	 * even randomized.
	 *   That means either we keep the mmap() open or we do a read() into a
	 * constant buffer
	 * */
#define LOCAL_SEND_BUFSIZE (64 * 1024)
	static char *local_send_buffer = NULL;

	/* the remote side closed the connection before without shutdown request
	 * - IE
	 * - wget
	 * if keep-alive is disabled */

	if (con->keep_alive == 0) {
		SSL_set_shutdown(sock->ssl, SSL_RECEIVED_SHUTDOWN);
	}

	for(c = cq->first; c; c = c->next) {
		int chunk_finished = 0;

		switch(c->type) {
		case MEM_CHUNK: {
			char * offset;
			size_t toSend;
			ssize_t r = 0;

			if (c->mem->used == 0) {
				chunk_finished = 1;
				break;
			}

			offset = c->mem->ptr + c->offset;
			toSend = c->mem->used - 1 - c->offset;

			/**
			 * SSL_write man-page
			 *
			 * WARNING
			 *        When an SSL_write() operation has to be repeated because of
			 *        SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE, it must be
			 *        repeated with the same arguments.
			 *
			 * SSL_write(..., 0) return 0 which is handle as an error (Success)
			 * checking toSend and not calling SSL_write() is simpler
			 */

			ERR_clear_error();
			if (toSend != 0 && (r = SSL_write(sock->ssl, offset, toSend)) <= 0) {
				unsigned long err;

				switch ((ssl_r = SSL_get_error(sock->ssl, r))) {
				case SSL_ERROR_WANT_WRITE:
					break;
				case SSL_ERROR_SYSCALL:
					/* perhaps we have error waiting in our error-queue */
					if (0 != (err = ERR_get_error())) {
						do {
							ERROR("SSL_write(): SSL_get_error() = %d,  SSL_write() = %zd, msg = %s",
									ssl_r, r,
									ERR_error_string(err, NULL));
						} while((err = ERR_get_error()));
					} else if (r == -1) {
						/* no, but we have errno */
						switch(errno) {
						case EPIPE:
						case ECONNRESET:
							return NETWORK_STATUS_CONNECTION_CLOSE;
						default:
							ERROR("SSL_write(): SSL_get_error() = %d,  SSL_write() = %zd, errmsg = %s (%d)",
									ssl_r, r,
									strerror(errno), errno);
							break;
						}
					} else {
						/* neither error-queue nor errno ? */
						ERROR("SSL_write(): SSL_get_error() = %d,  SSL_write() = %zd, errmsg = %s (%d)",
									ssl_r, r,
									strerror(errno), errno);
					}

					return  NETWORK_STATUS_FATAL_ERROR;
				case SSL_ERROR_ZERO_RETURN:
					/* clean shutdown on the remote side */

					if (r == 0) return NETWORK_STATUS_CONNECTION_CLOSE;

					/* fall through */
				default:
					while((err = ERR_get_error())) {
						ERROR("SSL_write(): SSL_get_error() = %d,  SSL_write() = %zd, msg = %s",
								ssl_r, r,
								ERR_error_string(err, NULL));
					}

					return  NETWORK_STATUS_FATAL_ERROR;
				}
			} else {
				c->offset += r;
				cq->bytes_out += r;
			}

			if (c->offset == (off_t)c->mem->used - 1) {
				chunk_finished = 1;
			}

			break;
		}
		case FILE_CHUNK: {
			char *s;
			ssize_t r;
			stat_cache_entry *sce = NULL;
			int ifd;
			int write_wait = 0;

			if (HANDLER_ERROR == stat_cache_get_entry(srv, con, c->file.name, &sce)) {
				ERROR("stat_cache_get_entry(%s) failed: %s", SAFE_BUF_STR(c->file.name), strerror(errno));

				return NETWORK_STATUS_FATAL_ERROR;
			}

			if (NULL == local_send_buffer) {
				local_send_buffer = malloc(LOCAL_SEND_BUFSIZE);
				assert(local_send_buffer);
			}

			do {
				off_t offset = c->file.start + c->offset;
				off_t toSend = c->file.length - c->offset;

				if (toSend > LOCAL_SEND_BUFSIZE) toSend = LOCAL_SEND_BUFSIZE;

				if (-1 == (ifd = open(BUF_STR(c->file.name), O_RDONLY))) {
					ERROR("open(%s) failed: %s", SAFE_BUF_STR(c->file.name), strerror(errno));

					return NETWORK_STATUS_FATAL_ERROR;
				}


				lseek(ifd, offset, SEEK_SET);
				if (-1 == (toSend = read(ifd, local_send_buffer, toSend))) {
					close(ifd);
					
					ERROR("read(%s) failed: %s", SAFE_BUF_STR(c->file.name), strerror(errno));

					return NETWORK_STATUS_FATAL_ERROR;
				}

				s = local_send_buffer;

				close(ifd);

				ERR_clear_error();
				if ((r = SSL_write(sock->ssl, s, toSend)) <= 0) {
					unsigned long err;

					switch ((ssl_r = SSL_get_error(sock->ssl, r))) {
					case SSL_ERROR_WANT_WRITE:
						write_wait = 1;
						break;
					case SSL_ERROR_SYSCALL:
						/* perhaps we have error waiting in our error-queue */
						if (0 != (err = ERR_get_error())) {
							do {
								ERROR("SSL_write(): ssl-error: %d (ret = %zd): %s",
										ssl_r, r,
										ERR_error_string(err, NULL));
							} while((err = ERR_get_error()));
						} else if (r == -1) {
							/* no, but we have errno */
							switch(errno) {
							case EPIPE:
							case ECONNRESET:
								return NETWORK_STATUS_CONNECTION_CLOSE;
							default:
								ERROR("SSL_write(): ssl-error: %d (ret = %zd). errno=%d, %s",
										ssl_r, r, errno,
										strerror(errno));
								break;
							}
						} else {
							ERROR("SSL_write(): ssl-error: %d (ret = %zd). errno=%d, %s",
										ssl_r, r, errno,
										strerror(errno));
						}

						return  NETWORK_STATUS_FATAL_ERROR;
					case SSL_ERROR_ZERO_RETURN:
						/* clean shutdown on the remote side */

						if (r == 0)  return NETWORK_STATUS_CONNECTION_CLOSE;

						/* fall thourgh */
					default:
						while((err = ERR_get_error())) {
							ERROR("SSL_write(): ssl-error: %d (ret = %zd), %s",
									ssl_r, r,
									ERR_error_string(err, NULL));
						}

						return NETWORK_STATUS_FATAL_ERROR;
					}
				} else {
					c->offset += r;
					cq->bytes_out += r;
				}

				if (c->offset == c->file.length) {
					chunk_finished = 1;
				}
			} while(!chunk_finished && !write_wait);

			break;
		}
		default:
			ERROR("type not known: %d", c->type);

			return NETWORK_STATUS_FATAL_ERROR;
		}

		if (!chunk_finished) {
			/* not finished yet */
			return NETWORK_STATUS_WAIT_FOR_EVENT;
		}
	}

	return NETWORK_STATUS_SUCCESS;
}
#endif

#if 0
network_openssl_init(void) {
	p->write_ssl = network_openssl_write_chunkset;
}
#endif