External Public-Key Authentication API (#72) * Implemented dynamic loading of an external plug-in shared library to delegate public key authentication * Moved conditional compilation of the plugin infrastructure into the configure.ac script to be able to add -ldl to dropbear build only when the flag is enabled * Added tags file to the ignore list * Updated API to have the constructor to return function pointers in the pliugin instance. Added support for passing user name to the checkpubkey function. Added options to the session returned by the plugin and have dropbear to parse and process them * Added -rdynamic to the linker flags when EPKA is enabled * Changed the API to pass a previously created session to the checkPubKey function (created during preauth) * Added documentation to the API * Added parameter addrstring to plugin creation function * Modified the API to retrieve the auth options. Instead of having them as field of the EPKASession struct, they are stored internally (plugin-dependent) in the plugin/session and retrieved through a pointer to a function (in the session) * Changed option string to be a simple char * instead of unsigned char *

#ifndef FUZZ_WRAPFD_H
#define FUZZ_WRAPFD_H

#include "buffer.h"

enum wrapfd_mode {
    UNUSED = 0,
    PLAIN,
    INPROGRESS,
    RANDOMIN
};

void wrapfd_setup(void);
void wrapfd_setseed(uint32_t seed);
// doesn't take ownership of buf. buf is optional.
void wrapfd_add(int fd, buffer *buf, enum wrapfd_mode mode);

// called via #defines for read/write/select
int wrapfd_read(int fd, void *out, size_t count);
int wrapfd_write(int fd, const void* in, size_t count);
int wrapfd_select(int nfds, fd_set *readfds, fd_set *writefds, 
    fd_set *exceptfds, struct timeval *timeout);
int wrapfd_close(int fd);

#endif // FUZZ_WRAPFD_H