/*      $OpenBSD: smtp.h,v 1.5 2024/06/02 23:26:39 jsg Exp $    */

/*
 * Copyright (c) 2018 Eric Faurot <eric@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define TLS_NO          0
#define TLS_YES         1
#define TLS_FORCE       2
#define TLS_SMTPS       3

#define CERT_OK         0
#define CERT_UNKNOWN    1
#define CERT_INVALID    2

#define FAIL_INTERNAL   1       /* malloc, etc. (check errno)  */
#define FAIL_CONN       2       /* disconnect, timeout... (check errno) */
#define FAIL_PROTO      3       /* protocol violation */
#define FAIL_IMPL       4       /* server lacks a required feature */
#define FAIL_RESP       5       /* rejected command */

struct smtp_params {

        /* Client options */
        size_t                   linemax;       /* max input line size */
        size_t                   ibufmax;       /* max input buffer size */
        size_t                   obufmax;       /* max output buffer size */

        /* Connection settings */
        const struct sockaddr   *dst;           /* address to connect to */
        const struct sockaddr   *src;           /* address to bind to */
        int                      timeout;       /* timeout in seconds */

        /* TLS options */
        int                      tls_req;       /* requested TLS mode */
        int                      tls_verify;    /* need valid server certificate */
        const char              *tls_servname;  /* SNI */

        /* SMTP options */
        int                      lmtp;          /* use LMTP protocol */
        const char              *helo;          /* string to use with HELO */
        const char              *auth_user;     /* for AUTH */
        const char              *auth_pass;     /* for AUTH */
};

struct smtp_rcpt {
        const char      *to;
        const char      *dsn_notify;
        const char      *dsn_orcpt;
        int              done;
};

struct smtp_mail {
        const char              *from;
        const char              *dsn_ret;
        const char              *dsn_envid;
        struct smtp_rcpt        *rcpt;
        int                      rcptcount;
        FILE                    *fp;
};

struct smtp_status {
        struct smtp_rcpt        *rcpt;
        const char              *cmd;
        const char              *status;
};

struct smtp_client;

/* smtp_client.c */
struct smtp_client *smtp_connect(const struct smtp_params *, void *);
void smtp_cert_verified(struct smtp_client *, int);
void smtp_set_tls(struct smtp_client *, void *);
void smtp_quit(struct smtp_client *);
void smtp_sendmail(struct smtp_client *, struct smtp_mail *);

/* callbacks */
void smtp_require_tls(void *, struct smtp_client *);
void smtp_ready(void *, struct smtp_client *);
void smtp_failed(void *, struct smtp_client *, int, const char *);
void smtp_closed(void *, struct smtp_client *);
void smtp_status(void *, struct smtp_client *, struct smtp_status *);
void smtp_done(void *, struct smtp_client *, struct smtp_mail *);