tunala.h revision 160814 
1/* Tunala ("Tunneler with a New Zealand accent")
2 *
3 * Written by Geoff Thorpe, but endorsed/supported by noone. Please use this is
4 * if it's useful or informative to you, but it's only here as a scratchpad for
5 * ideas about how you might (or might not) program with OpenSSL. If you deploy
6 * this is in a mission-critical environment, and have not read, understood,
7 * audited, and modified this code to your satisfaction, and the result is that
8 * all hell breaks loose and you are looking for a new employer, then it proves
9 * nothing except perhaps that Darwinism is alive and well. Let's just say, *I*
10 * don't use this in a mission-critical environment, so it would be stupid for
11 * anyone to assume that it is solid and/or tested enough when even its author
12 * doesn't place that much trust in it. You have been warned.
13 *
14 * With thanks to Cryptographic Appliances, Inc.
15 */
16
17#ifndef _TUNALA_H
18#define _TUNALA_H
19
20/* pull in autoconf fluff */
21#ifndef NO_CONFIG_H
22#include "config.h"
23#else
24/* We don't have autoconf, we have to set all of these unless a tweaked Makefile
25 * tells us not to ... */
26/* headers */
27#ifndef NO_HAVE_SELECT
28#define HAVE_SELECT
29#endif
30#ifndef NO_HAVE_SOCKET
31#define HAVE_SOCKET
32#endif
33#ifndef NO_HAVE_UNISTD_H
34#define HAVE_UNISTD_H
35#endif
36#ifndef NO_HAVE_FCNTL_H
37#define HAVE_FCNTL_H
38#endif
39#ifndef NO_HAVE_LIMITS_H
40#define HAVE_LIMITS_H
41#endif
42/* features */
43#ifndef NO_HAVE_STRSTR
44#define HAVE_STRSTR
45#endif
46#ifndef NO_HAVE_STRTOUL
47#define HAVE_STRTOUL
48#endif
49#endif
50
51#if !defined(HAVE_SELECT) || !defined(HAVE_SOCKET)
52#error "can't build without some network basics like select() and socket()"
53#endif
54
55#include <stdlib.h>
56#ifndef NO_SYSTEM_H
57#include <string.h>
58#ifdef HAVE_UNISTD_H
59#include <unistd.h>
60#endif
61#ifdef HAVE_FCNTL_H
62#include <fcntl.h>
63#endif
64#ifdef HAVE_LIMITS_H
65#include <limits.h>
66#endif
67#include <netdb.h>
68#include <signal.h>
69#include <sys/socket.h>
70#include <sys/types.h>
71#include <netinet/in.h>
72#endif /* !defined(NO_SYSTEM_H) */
73
74#ifndef NO_OPENSSL
75#include <openssl/err.h>
76#include <openssl/engine.h>
77#include <openssl/ssl.h>
78#endif /* !defined(NO_OPENSSL) */
79
80#ifndef OPENSSL_NO_BUFFER
81/* This is the generic "buffer" type that is used when feeding the
82 * state-machine. It's basically a FIFO with respect to the "adddata" &
83 * "takedata" type functions that operate on it. */
84#define MAX_DATA_SIZE 16384
85typedef struct _buffer_t {
86	unsigned char data[MAX_DATA_SIZE];
87	unsigned int used;
88	/* Statistical values - counts the total number of bytes read in and
89	 * read out (respectively) since "buffer_init()" */
90	unsigned long total_in, total_out;
91} buffer_t;
92
93/* Initialise a buffer structure before use */
94void buffer_init(buffer_t *buf);
95/* Cleanup a buffer structure - presently not needed, but if buffer_t is
96 * converted to using dynamic allocation, this would be required - so should be
97 * called to protect against an explosion of memory leaks later if the change is
98 * made. */
99void buffer_close(buffer_t *buf);
100
101/* Basic functions to manipulate buffers */
102
103unsigned int buffer_used(buffer_t *buf); /* How much data in the buffer */
104unsigned int buffer_unused(buffer_t *buf); /* How much space in the buffer */
105int buffer_full(buffer_t *buf); /* Boolean, is it full? */
106int buffer_notfull(buffer_t *buf); /* Boolean, is it not full? */
107int buffer_empty(buffer_t *buf); /* Boolean, is it empty? */
108int buffer_notempty(buffer_t *buf); /* Boolean, is it not empty? */
109unsigned long buffer_total_in(buffer_t *buf); /* Total bytes written to buffer */
110unsigned long buffer_total_out(buffer_t *buf); /* Total bytes read from buffer */
111
112#if 0 /* Currently used only within buffer.c - better to expose only
113       * higher-level functions anyway */
114/* Add data to the tail of the buffer, returns the amount that was actually
115 * added (so, you need to check if return value is less than size) */
116unsigned int buffer_adddata(buffer_t *buf, const unsigned char *ptr,
117		unsigned int size);
118
119/* Take data from the front of the buffer (and scroll the rest forward). If
120 * "ptr" is NULL, this just removes data off the front of the buffer. Return
121 * value is the amount actually removed (can be less than size if the buffer has
122 * too little data). */
123unsigned int buffer_takedata(buffer_t *buf, unsigned char *ptr,
124		unsigned int size);
125
126/* Flushes as much data as possible out of the "from" buffer into the "to"
127 * buffer. Return value is the amount moved. The amount moved can be restricted
128 * to a maximum by specifying "cap" - setting it to -1 means no limit. */
129unsigned int buffer_tobuffer(buffer_t *to, buffer_t *from, int cap);
130#endif
131
132#ifndef NO_IP
133/* Read or write between a file-descriptor and a buffer */
134int buffer_from_fd(buffer_t *buf, int fd);
135int buffer_to_fd(buffer_t *buf, int fd);
136#endif /* !defined(NO_IP) */
137
138#ifndef NO_OPENSSL
139/* Read or write between an SSL or BIO and a buffer */
140void buffer_from_SSL(buffer_t *buf, SSL *ssl);
141void buffer_to_SSL(buffer_t *buf, SSL *ssl);
142void buffer_from_BIO(buffer_t *buf, BIO *bio);
143void buffer_to_BIO(buffer_t *buf, BIO *bio);
144
145/* Callbacks */
146void cb_ssl_info(const SSL *s, int where, int ret);
147void cb_ssl_info_set_output(FILE *fp); /* Called if output should be sent too */
148int cb_ssl_verify(int ok, X509_STORE_CTX *ctx);
149void cb_ssl_verify_set_output(FILE *fp);
150void cb_ssl_verify_set_depth(unsigned int verify_depth);
151void cb_ssl_verify_set_level(unsigned int level);
152RSA *cb_generate_tmp_rsa(SSL *s, int is_export, int keylength);
153#endif /* !defined(NO_OPENSSL) */
154#endif /* !defined(OPENSSL_NO_BUFFER) */
155
156#ifndef NO_TUNALA
157#ifdef OPENSSL_NO_BUFFER
158#error "TUNALA section of tunala.h requires BUFFER support"
159#endif
160typedef struct _state_machine_t {
161	SSL *ssl;
162	BIO *bio_intossl;
163	BIO *bio_fromssl;
164	buffer_t clean_in, clean_out;
165	buffer_t dirty_in, dirty_out;
166} state_machine_t;
167typedef enum {
168	SM_CLEAN_IN, SM_CLEAN_OUT,
169	SM_DIRTY_IN, SM_DIRTY_OUT
170} sm_buffer_t;
171void state_machine_init(state_machine_t *machine);
172void state_machine_close(state_machine_t *machine);
173buffer_t *state_machine_get_buffer(state_machine_t *machine, sm_buffer_t type);
174SSL *state_machine_get_SSL(state_machine_t *machine);
175int state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server);
176/* Performs the data-IO loop and returns zero if the machine should close */
177int state_machine_churn(state_machine_t *machine);
178/* Is used to handle closing conditions - namely when one side of the tunnel has
179 * closed but the other should finish flushing. */
180int state_machine_close_clean(state_machine_t *machine);
181int state_machine_close_dirty(state_machine_t *machine);
182#endif /* !defined(NO_TUNALA) */
183
184#ifndef NO_IP
185/* Initialise anything related to the networking. This includes blocking pesky
186 * SIGPIPE signals. */
187int ip_initialise(void);
188/* ip is the 4-byte ip address (eg. 127.0.0.1 is {0x7F,0x00,0x00,0x01}), port is
189 * the port to listen on (host byte order), and the return value is the
190 * file-descriptor or -1 on error. */
191int ip_create_listener_split(const char *ip, unsigned short port);
192/* Same semantics as above. */
193int ip_create_connection_split(const char *ip, unsigned short port);
194/* Converts a string into the ip/port before calling the above */
195int ip_create_listener(const char *address);
196int ip_create_connection(const char *address);
197/* Just does a string conversion on its own. NB: If accept_all_ip is non-zero,
198 * then the address string could be just a port. Ie. it's suitable for a
199 * listening address but not a connecting address. */
200int ip_parse_address(const char *address, const char **parsed_ip,
201		unsigned short *port, int accept_all_ip);
202/* Accepts an incoming connection through the listener. Assumes selects and
203 * what-not have deemed it an appropriate thing to do. */
204int ip_accept_connection(int listen_fd);
205#endif /* !defined(NO_IP) */
206
207/* These functions wrap up things that can be portability hassles. */
208int int_strtoul(const char *str, unsigned long *val);
209#ifdef HAVE_STRSTR
210#define int_strstr strstr
211#else
212char *int_strstr(const char *haystack, const char *needle);
213#endif
214
215#endif /* !defined(_TUNALA_H) */
216