spamd/libspamc.h

/*
 * This code is copyright 2001 by Craig Hughes
 * Conversion to a thread-safe shared library copyright 2002 Liam Widdowson
 * Portions copyright 2002 by Brad Jorsch
 * It is licensed under the same license as Perl itself.  The text of this
 * license is included in the SpamAssassin distribution in the file named
 * "License".
 */
#ifndef LIBSPAMC_H
#define LIBSPAMC_H 1

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>

#define EX_NOTSPAM		  0
#define EX_ISSPAM		  1
#define EX_TOOBIG		866

/* Aug 14, 2002 bj: Bitflags instead of lots of bool parameters */
#define SPAMC_MODE_MASK      1
#define SPAMC_RAW_MODE       0
#define SPAMC_BSMTP_MODE     1

#define SPAMC_USE_SSL	     (1<<27)
#define SPAMC_SAFE_FALLBACK  (1<<28)
#define SPAMC_CHECK_ONLY     (1<<29)

/* Jan 30, 2003 ym: added reporting options */
#define SPAMC_REPORT         (1<<26)
#define SPAMC_REPORT_IFSPAM  (1<<25)

/* Feb  1 2003 jm: might as well fix bug 191 as well */
#define SPAMC_SYMBOLS        (1<<24)

/* 2003/04/16 SJF: randomize hostname order (quasi load balancing) */
#define SPAMC_RANDOMIZE_HOSTS (1<<23)


/* Aug 14, 2002 bj: A struct for storing a message-in-progress */
typedef enum {
    MESSAGE_NONE,
    MESSAGE_ERROR,
    MESSAGE_RAW,
    MESSAGE_BSMTP,
    MAX_MESSAGE_TYPE
} message_type_t;

struct libspamc_private_message;

struct message {
    /* Set before passing the struct on! */
    int max_len;  /* messages larger than this will return EX_TOOBIG */
    int timeout;  /* timeout for read() system calls */

    /* Filled in by message_read */
    message_type_t type;
    char *raw; int raw_len;   /* Raw message buffer */
    char *pre; int pre_len;   /* Pre-message data (e.g. SMTP commands) */
    char *msg; int msg_len;   /* The message */
    char *post; int post_len; /* Post-message data (e.g. SMTP commands) */
    int content_length;

    /* Filled in by filter_message */
    int is_spam;              /* EX_ISSPAM if the message is spam, EX_NOTSPAM
                                 if not */
    float score, threshold;   /* score and threshold */
    char *out; int out_len;   /* Output from spamd. Either the filtered
                                 message, or the check-only response. Or else,
                                 a pointer to msg above. */

    /* these members added in SpamAssassin version 2.60: */
    struct libspamc_private_message *priv;
};

/*------------------------------------------------------------------------
 * TRANSPORT (2004/04/16 - SJF)
 *
 * The code to connect with the daemon has gotten more complicated: support
 * for SSL, fallback to multiple hosts, and using UNIX domain sockets. The
 * code has gotten ugly with way too many parameters being passed all around.
 *
 * So we've created this object to hold all the info required to connect with
 * the remote site, including a self-contained list of all the IP addresses
 * in the event this is using TCP sockets. These multiple IPs can be obtained
 * only from DNS returning more than one A record for a single name, and
 * this allows for fallback.
 *
 * We also allow a kind of quasi-load balancing, where we take the list of
 * A records from DNS and randomize them before starting out - this lets
 * us spread the load out among multiple servers if desired. The idea for
 * load balancing goes to Jeremy Zawodny.
 *
 * By putting all our data here, we remove "fallback" from being a special
 * case. We may find ourselves with several IP addresses, but if the user
 * disables fallback, we set the IP address count to one. Now the connect
 * code just loops over that same address.
 */
#define TRANSPORT_LOCALHOST 0x01	/* TCP to localhost only */
#define	TRANSPORT_TCP	    0x02	/* standard TCP socket	 */
#define TRANSPORT_UNIX	    0x03	/* UNIX domain socket	 */

#define TRANSPORT_MAX_HOSTS 256		/* max hosts we can failover between */

struct transport {
	int		type;

	const char	*socketpath;	/* for UNIX dommain socket      */
	const char	*hostname;	/* for TCP sockets              */

	unsigned short	port;		/* for TCP sockets              */

	struct in_addr	hosts[TRANSPORT_MAX_HOSTS];
	int		nhosts;
};

extern void transport_init(struct transport *tp);
extern int  transport_setup(struct transport *tp, int flags);

/* Aug 14, 2002 bj: New interface functions */

/* Read in a message from the fd, with the mode specified in the flags.
 * Returns EX_OK on success, EX_otherwise on failure. On failure, m may be
 * either MESSAGE_NONE or MESSAGE_ERROR. */
int message_read(int in_fd, int flags, struct message *m);

/* Write out a message to the fd, as specified by m->type. Note that
 * MESSAGE_NONE messages have nothing to write. Also note that if you ran the
 * message through message_filter with SPAMC_CHECK_ONLY, it will only output
 * the "score/threshold" line. */
long message_write(int out_fd, struct message *m);

/* Process the message through the spamd filter, making as many connection
 * attempts as are implied by the transport structure. To make this do
 * failover, more than one host is defined, but if there is only one there,
 * no failover is done.
 */
int message_filter(struct transport *tp, const char *username,
		int flags, struct message *m);

/* Dump the message. If there is any data in the message (typically, m->type
 * will be MESSAGE_ERROR) it will be message_writed. Then, fd_in will be piped
 * to fd_out intol EOF. This is particularly useful if you get back an
 * EX_TOOBIG. */
void message_dump(int in_fd, int out_fd, struct message *m);

/* Do a message_read->message_filter->message_write sequence, handling errors
 * appropriately with dump_message or appropriate CHECK_ONLY output. Returns
 * EX_OK or EX_ISSPAM/EX_NOTSPAM on success, some error EX on error. */
int message_process(struct transport *trans, char *username, int max_size, int in_fd, int out_fd, const int flags);

/* Cleanup the resources we allocated for storing the message. Call after
 * you're done processing. */
void message_cleanup(struct message *m);

/* Aug 14, 2002 bj: This is now legacy, don't use it. */
int process_message(struct transport *tp, char *username, 
                    int max_size, int in_fd, int out_fd,
                    const int check_only, const int safe_fallback);

#endif