blacklist(3) - NetBSD Manual Pages

LIBBLACKLIST(3)         NetBSD Library Functions Manual        LIBBLACKLIST(3)


NAME

     blacklist_open, blacklist_close, blacklist_r, blacklist, blacklist_sa,
     blacklist_sa_r -- Blacklistd notification library


LIBRARY

     library ``libblacklist''


SYNOPSIS

     #include <blacklist.h>

     struct blacklist *
     blacklist_open(void);

     void
     blacklist_close(struct blacklist *cookie);

     int
     blacklist(int action, int fd, const char *msg);

     int
     blacklist_r(struct blacklist *cookie, int action, int fd,
         const char *msg);

     int
     blacklist_sa(int action, int fd, const struct sockaddr *sa,
         socklen_t salen, const char *msg);

     int
     blacklist_sa_r(struct blacklist *cookie, int action, int fd,
         const struct sockaddr *sa, socklen_t salen, const char *msg);


DESCRIPTION

     These functions can be used by daemons to notify blacklistd(8) about suc-
     cessful and failed remote connections so that blacklistd can block or
     release port access to prevent Denial of Service attacks.

     The function blacklist_open() creates the necessary state to communicate
     with blacklistd(8) and returns a pointer to it, or NULL on failure.

     The blacklist_close() function frees all memory and resources used.

     The blacklist() function sends a message to blacklistd(8), with an action
     argument specifying 1 for a failed connection or 0 for a successful con-
     nection, a file descriptor fd specifying the accepted file descriptor
     connected to the client, and an optional message in the msg argument.

     The blacklist_r() function is more efficient because it keeps the black-
     list state around.

     The blacklist_sa() and blacklist_sa_r() functions can be used with uncon-
     nected sockets, where getpeername(2) will not work, the server will pass
     the peer name in the message.

     All functions log errors to syslogd(8).


RETURN VALUES

     The function blacklist_open() returns a cookie on success and NULL on
     failure setting errno to an appropriate value.

     The functions blacklist(), blacklist_sa(), and blacklist_sa_r() return 0
     on success and -1 on failure setting errno to an appropriate value.


SEE ALSO

     blacklistd.conf(5), blacklistd(8)


AUTHORS

     Christos Zoulas

NetBSD 9.2                     January 22, 2015                     NetBSD 9.2