215 lines
7.8 KiB
C
215 lines
7.8 KiB
C
/* Tunala ("Tunneler with a New Zealand accent")
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*
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* Written by Geoff Thorpe, but endorsed/supported by noone. Please use this is
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* if it's useful or informative to you, but it's only here as a scratchpad for
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* ideas about how you might (or might not) program with OpenSSL. If you deploy
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* this is in a mission-critical environment, and have not read, understood,
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* audited, and modified this code to your satisfaction, and the result is that
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* all hell breaks loose and you are looking for a new employer, then it proves
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* nothing except perhaps that Darwinism is alive and well. Let's just say, *I*
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* don't use this in a mission-critical environment, so it would be stupid for
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* anyone to assume that it is solid and/or tested enough when even its author
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* doesn't place that much trust in it. You have been warned.
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*
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* With thanks to Cryptographic Appliances, Inc.
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*/
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#ifndef _TUNALA_H
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#define _TUNALA_H
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/* pull in autoconf fluff */
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#ifndef NO_CONFIG_H
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#include "config.h"
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#else
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/* We don't have autoconf, we have to set all of these unless a tweaked Makefile
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* tells us not to ... */
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/* headers */
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#ifndef NO_HAVE_SELECT
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#define HAVE_SELECT
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#endif
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#ifndef NO_HAVE_SOCKET
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#define HAVE_SOCKET
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#endif
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#ifndef NO_HAVE_UNISTD_H
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#define HAVE_UNISTD_H
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#endif
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#ifndef NO_HAVE_FCNTL_H
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#define HAVE_FCNTL_H
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#endif
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#ifndef NO_HAVE_LIMITS_H
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#define HAVE_LIMITS_H
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#endif
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/* features */
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#ifndef NO_HAVE_STRSTR
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#define HAVE_STRSTR
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#endif
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#ifndef NO_HAVE_STRTOUL
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#define HAVE_STRTOUL
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#endif
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#endif
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#if !defined(HAVE_SELECT) || !defined(HAVE_SOCKET)
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#error "can't build without some network basics like select() and socket()"
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#endif
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#include <stdlib.h>
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#ifndef NO_SYSTEM_H
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#include <string.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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#ifdef HAVE_LIMITS_H
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#include <limits.h>
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#endif
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#include <netdb.h>
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#include <signal.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <netinet/in.h>
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#endif /* !defined(NO_SYSTEM_H) */
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#ifndef NO_OPENSSL
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#include <openssl/err.h>
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#include <openssl/engine.h>
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#include <openssl/ssl.h>
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#endif /* !defined(NO_OPENSSL) */
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#ifndef OPENSSL_NO_BUFFER
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/* This is the generic "buffer" type that is used when feeding the
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* state-machine. It's basically a FIFO with respect to the "adddata" &
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* "takedata" type functions that operate on it. */
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#define MAX_DATA_SIZE 16384
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typedef struct _buffer_t {
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unsigned char data[MAX_DATA_SIZE];
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unsigned int used;
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/* Statistical values - counts the total number of bytes read in and
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* read out (respectively) since "buffer_init()" */
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unsigned long total_in, total_out;
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} buffer_t;
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/* Initialise a buffer structure before use */
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void buffer_init(buffer_t *buf);
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/* Cleanup a buffer structure - presently not needed, but if buffer_t is
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* converted to using dynamic allocation, this would be required - so should be
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* called to protect against an explosion of memory leaks later if the change is
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* made. */
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void buffer_close(buffer_t *buf);
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/* Basic functions to manipulate buffers */
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unsigned int buffer_used(buffer_t *buf); /* How much data in the buffer */
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unsigned int buffer_unused(buffer_t *buf); /* How much space in the buffer */
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int buffer_full(buffer_t *buf); /* Boolean, is it full? */
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int buffer_notfull(buffer_t *buf); /* Boolean, is it not full? */
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int buffer_empty(buffer_t *buf); /* Boolean, is it empty? */
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int buffer_notempty(buffer_t *buf); /* Boolean, is it not empty? */
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unsigned long buffer_total_in(buffer_t *buf); /* Total bytes written to buffer */
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unsigned long buffer_total_out(buffer_t *buf); /* Total bytes read from buffer */
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#if 0 /* Currently used only within buffer.c - better to expose only
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* higher-level functions anyway */
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/* Add data to the tail of the buffer, returns the amount that was actually
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* added (so, you need to check if return value is less than size) */
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unsigned int buffer_adddata(buffer_t *buf, const unsigned char *ptr,
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unsigned int size);
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/* Take data from the front of the buffer (and scroll the rest forward). If
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* "ptr" is NULL, this just removes data off the front of the buffer. Return
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* value is the amount actually removed (can be less than size if the buffer has
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* too little data). */
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unsigned int buffer_takedata(buffer_t *buf, unsigned char *ptr,
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unsigned int size);
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/* Flushes as much data as possible out of the "from" buffer into the "to"
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* buffer. Return value is the amount moved. The amount moved can be restricted
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* to a maximum by specifying "cap" - setting it to -1 means no limit. */
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unsigned int buffer_tobuffer(buffer_t *to, buffer_t *from, int cap);
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#endif
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#ifndef NO_IP
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/* Read or write between a file-descriptor and a buffer */
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int buffer_from_fd(buffer_t *buf, int fd);
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int buffer_to_fd(buffer_t *buf, int fd);
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#endif /* !defined(NO_IP) */
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#ifndef NO_OPENSSL
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/* Read or write between an SSL or BIO and a buffer */
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void buffer_from_SSL(buffer_t *buf, SSL *ssl);
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void buffer_to_SSL(buffer_t *buf, SSL *ssl);
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void buffer_from_BIO(buffer_t *buf, BIO *bio);
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void buffer_to_BIO(buffer_t *buf, BIO *bio);
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/* Callbacks */
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void cb_ssl_info(const SSL *s, int where, int ret);
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void cb_ssl_info_set_output(FILE *fp); /* Called if output should be sent too */
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int cb_ssl_verify(int ok, X509_STORE_CTX *ctx);
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void cb_ssl_verify_set_output(FILE *fp);
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void cb_ssl_verify_set_depth(unsigned int verify_depth);
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void cb_ssl_verify_set_level(unsigned int level);
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#endif /* !defined(NO_OPENSSL) */
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#endif /* !defined(OPENSSL_NO_BUFFER) */
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#ifndef NO_TUNALA
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#ifdef OPENSSL_NO_BUFFER
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#error "TUNALA section of tunala.h requires BUFFER support"
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#endif
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typedef struct _state_machine_t {
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SSL *ssl;
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BIO *bio_intossl;
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BIO *bio_fromssl;
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buffer_t clean_in, clean_out;
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buffer_t dirty_in, dirty_out;
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} state_machine_t;
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typedef enum {
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SM_CLEAN_IN, SM_CLEAN_OUT,
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SM_DIRTY_IN, SM_DIRTY_OUT
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} sm_buffer_t;
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void state_machine_init(state_machine_t *machine);
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void state_machine_close(state_machine_t *machine);
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buffer_t *state_machine_get_buffer(state_machine_t *machine, sm_buffer_t type);
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SSL *state_machine_get_SSL(state_machine_t *machine);
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int state_machine_set_SSL(state_machine_t *machine, SSL *ssl, int is_server);
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/* Performs the data-IO loop and returns zero if the machine should close */
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int state_machine_churn(state_machine_t *machine);
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/* Is used to handle closing conditions - namely when one side of the tunnel has
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* closed but the other should finish flushing. */
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int state_machine_close_clean(state_machine_t *machine);
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int state_machine_close_dirty(state_machine_t *machine);
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#endif /* !defined(NO_TUNALA) */
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#ifndef NO_IP
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/* Initialise anything related to the networking. This includes blocking pesky
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* SIGPIPE signals. */
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int ip_initialise(void);
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/* ip is the 4-byte ip address (eg. 127.0.0.1 is {0x7F,0x00,0x00,0x01}), port is
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* the port to listen on (host byte order), and the return value is the
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* file-descriptor or -1 on error. */
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int ip_create_listener_split(const char *ip, unsigned short port);
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/* Same semantics as above. */
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int ip_create_connection_split(const char *ip, unsigned short port);
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/* Converts a string into the ip/port before calling the above */
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int ip_create_listener(const char *address);
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int ip_create_connection(const char *address);
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/* Just does a string conversion on its own. NB: If accept_all_ip is non-zero,
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* then the address string could be just a port. Ie. it's suitable for a
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* listening address but not a connecting address. */
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int ip_parse_address(const char *address, const char **parsed_ip,
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unsigned short *port, int accept_all_ip);
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/* Accepts an incoming connection through the listener. Assumes selects and
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* what-not have deemed it an appropriate thing to do. */
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int ip_accept_connection(int listen_fd);
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#endif /* !defined(NO_IP) */
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/* These functions wrap up things that can be portability hassles. */
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int int_strtoul(const char *str, unsigned long *val);
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#ifdef HAVE_STRSTR
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#define int_strstr strstr
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#else
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char *int_strstr(const char *haystack, const char *needle);
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#endif
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#endif /* !defined(_TUNALA_H) */
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