sendmail/libmilter/engine.c

	engine.c revision 3ee0e49223f178da635734759b9167f924321ff0
/*
 *  Copyright (c) 1999-2004, 2006 Sendmail, Inc. and its suppliers.
 *  All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 *
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: engine.c,v 8.121 2006/04/18 21:01:46 ca Exp $")

#include "libmilter.h"

#if NETINET || NETINET6
# include <arpa/inet.h>
#endif /* NETINET || NETINET6 */

/* generic argument for functions in the command table */
struct arg_struct
{
    size_t      a_len;      /* length of buffer */
    char        *a_buf;     /* argument string */
    int     a_idx;      /* index for macro array */
    SMFICTX_PTR a_ctx;      /* context */
};

typedef struct arg_struct genarg;

/* structure for commands received from MTA */
struct cmdfct_t
{
    char    cm_cmd;             /* command */
    int cm_argt;            /* type of arguments expected */
    int cm_next;            /* next state */
    int cm_todo;            /* what to do next */
    int cm_macros;          /* index for macros */
    int (*cm_fct) __P((genarg *));  /* function to execute */
};

typedef struct cmdfct_t cmdfct;

/* possible values for cm_argt */
#define CM_ARG0 0   /* no args */
#define CM_ARG1 1   /* one arg (string) */
#define CM_ARG2 2   /* two args (strings) */
#define CM_ARGA 4   /* one string and _SOCK_ADDR */
#define CM_ARGO 5   /* two integers */
#define CM_ARGV 8   /* \0 separated list of args, NULL-terminated */
#define CM_ARGN 9   /* \0 separated list of args (strings) */

/* possible values for cm_todo */
#define CT_CONT     0x0000  /* continue reading commands */
#define CT_IGNO     0x0001  /* continue even when error  */

/* not needed right now, done via return code instead */
#define CT_KEEP     0x0004  /* keep buffer (contains symbols) */
#define CT_END      0x0008  /* start replying */

/* index in macro array: macros only for these commands */
#define CI_NONE     (-1)
#define CI_CONN     0
#define CI_HELO     1
#define CI_MAIL     2
#define CI_RCPT     3
#define CI_EOM      4
#if CI_EOM >= MAX_MACROS_ENTRIES
ERROR: do not compile with CI_EOM >= MAX_MACROS_ENTRIES
#endif

/* function prototypes */
static int  st_abortfct __P((genarg *));
static int  st_macros __P((genarg *));
static int  st_optionneg __P((genarg *));
static int  st_bodychunk __P((genarg *));
static int  st_connectinfo __P((genarg *));
static int  st_bodyend __P((genarg *));
static int  st_helo __P((genarg *));
static int  st_header __P((genarg *));
static int  st_sender __P((genarg *));
static int  st_rcpt __P((genarg *));
#if SMFI_VERSION > 2
static int  st_unknown __P((genarg *));
#endif /* SMFI_VERSION > 2 */
#if SMFI_VERSION > 3
static int  st_data __P((genarg *));
#endif /* SMFI_VERSION > 3 */
static int  st_eoh __P((genarg *));
static int  st_quit __P((genarg *));
static int  sendreply __P((sfsistat, socket_t, struct timeval *, SMFICTX_PTR));
static void fix_stm __P((SMFICTX_PTR));
static bool trans_ok __P((int, int));
static char **dec_argv __P((char *, size_t));
static int  dec_arg2 __P((char *, size_t, char **, char **));

/* states */
#define ST_NONE (-1)
#define ST_INIT 0   /* initial state */
#define ST_OPTS 1   /* option negotiation */
#define ST_CONN 2   /* connection info */
#define ST_HELO 3   /* helo */
#define ST_MAIL 4   /* mail from */
#define ST_RCPT 5   /* rcpt to */
#define ST_DATA 6   /* data */
#define ST_HDRS 7   /* headers */
#define ST_EOHS 8   /* end of headers */
#define ST_BODY 9   /* body */
#define ST_ENDM 10  /* end of message */
#define ST_QUIT 11  /* quit */
#define ST_ABRT 12  /* abort */
#define ST_UNKN 13  /* unknown SMTP command */
#define ST_LAST ST_UNKN /* last valid state */
#define ST_SKIP 15  /* not a state but required for the state table */

/* in a mail transaction? must be before eom according to spec. */
#define ST_IN_MAIL(st)  ((st) >= ST_MAIL && (st) < ST_ENDM)

/*
**  set of next states
**  each state (ST_*) corresponds to bit in an int value (1 << state)
**  each state has a set of allowed transitions ('or' of bits of states)
**  so a state transition is valid if the mask of the next state
**  is set in the NX_* value
**  this function is coded in trans_ok(), see below.
*/

#define MI_MASK(x)  (0x0001 << (x)) /* generate a bit "mask" for a state */
#define NX_INIT (MI_MASK(ST_OPTS))
#define NX_OPTS (MI_MASK(ST_CONN) | MI_MASK(ST_UNKN))
#define NX_CONN (MI_MASK(ST_HELO) | MI_MASK(ST_MAIL) | MI_MASK(ST_UNKN))
#define NX_HELO (MI_MASK(ST_HELO) | MI_MASK(ST_MAIL) | MI_MASK(ST_UNKN))
#define NX_MAIL (MI_MASK(ST_RCPT) | MI_MASK(ST_ABRT) | MI_MASK(ST_UNKN))
#define NX_RCPT (MI_MASK(ST_HDRS) | MI_MASK(ST_EOHS) | MI_MASK(ST_DATA) | \
         MI_MASK(ST_BODY) | MI_MASK(ST_ENDM) | \
         MI_MASK(ST_RCPT) | MI_MASK(ST_ABRT) | MI_MASK(ST_UNKN))
#define NX_DATA (MI_MASK(ST_EOHS) | MI_MASK(ST_HDRS) | MI_MASK(ST_ABRT))
#define NX_HDRS (MI_MASK(ST_EOHS) | MI_MASK(ST_HDRS) | MI_MASK(ST_ABRT))
#define NX_EOHS (MI_MASK(ST_BODY) | MI_MASK(ST_ENDM) | MI_MASK(ST_ABRT))
#define NX_BODY (MI_MASK(ST_ENDM) | MI_MASK(ST_BODY) | MI_MASK(ST_ABRT))
#define NX_ENDM (MI_MASK(ST_QUIT) | MI_MASK(ST_MAIL) | MI_MASK(ST_UNKN))
#define NX_QUIT 0
#define NX_ABRT 0
#define NX_UNKN (MI_MASK(ST_HELO) | MI_MASK(ST_MAIL) | \
         MI_MASK(ST_RCPT) | MI_MASK(ST_ABRT) | \
         MI_MASK(ST_DATA) | \
         MI_MASK(ST_BODY) | MI_MASK(ST_UNKN) | \
         MI_MASK(ST_ABRT) | MI_MASK(ST_QUIT))
#define NX_SKIP MI_MASK(ST_SKIP)

static int next_states[] =
{
    NX_INIT,
    NX_OPTS,
    NX_CONN,
    NX_HELO,
    NX_MAIL,
    NX_RCPT,
    NX_DATA,
    NX_HDRS,
    NX_EOHS,
    NX_BODY,
    NX_ENDM,
    NX_QUIT,
    NX_ABRT,
    NX_UNKN
};

#define SIZE_NEXT_STATES    (sizeof(next_states) / sizeof(next_states[0]))

/* commands received by milter */
static cmdfct cmds[] =
{
{SMFIC_ABORT,   CM_ARG0, ST_ABRT,  CT_CONT, CI_NONE, st_abortfct    },
{SMFIC_MACRO,   CM_ARGV, ST_NONE,  CT_KEEP, CI_NONE, st_macros  },
{SMFIC_BODY,    CM_ARG1, ST_BODY,  CT_CONT, CI_NONE, st_bodychunk   },
{SMFIC_CONNECT, CM_ARG2, ST_CONN,  CT_CONT, CI_CONN, st_connectinfo },
{SMFIC_BODYEOB, CM_ARG1, ST_ENDM,  CT_CONT, CI_EOM,  st_bodyend },
{SMFIC_HELO,    CM_ARG1, ST_HELO,  CT_CONT, CI_HELO, st_helo    },
{SMFIC_HEADER,  CM_ARG2, ST_HDRS,  CT_CONT, CI_NONE, st_header  },
{SMFIC_MAIL,    CM_ARGV, ST_MAIL,  CT_CONT, CI_MAIL, st_sender  },
{SMFIC_OPTNEG,  CM_ARGO, ST_OPTS,  CT_CONT, CI_NONE, st_optionneg   },
{SMFIC_EOH, CM_ARG0, ST_EOHS,  CT_CONT, CI_NONE, st_eoh     },
{SMFIC_QUIT,    CM_ARG0, ST_QUIT,  CT_END,  CI_NONE, st_quit    },
#if SMFI_VERSION > 3
{SMFIC_DATA,    CM_ARG0, ST_DATA,  CT_CONT, CI_NONE, st_data    },
#endif /* SMFI_VERSION > 3 */
{SMFIC_RCPT,    CM_ARGV, ST_RCPT,  CT_IGNO, CI_RCPT, st_rcpt    }
#if SMFI_VERSION > 2
,{SMFIC_UNKNOWN,CM_ARG1, ST_UNKN,  CT_IGNO, CI_NONE, st_unknown }
#endif /* SMFI_VERSION > 2 */
};

/* additional (internal) reply codes */
#define _SMFIS_KEEP 20
#define _SMFIS_ABORT    21
#define _SMFIS_OPTIONS  22
#define _SMFIS_NOREPLY  23
#define _SMFIS_FAIL (-1)
#define _SMFIS_NONE (-2)

/*
**  MI_ENGINE -- receive commands and process them
**
**  Parameters:
**      ctx -- context structure
**
**  Returns:
**      MI_FAILURE/MI_SUCCESS
*/
int
mi_engine(ctx)
    SMFICTX_PTR ctx;
{
    size_t len;
    int i;
    socket_t sd;
    int ret = MI_SUCCESS;
    int ncmds = sizeof(cmds) / sizeof(cmdfct);
    int curstate = ST_INIT;
    int newstate;
    bool call_abort;
    sfsistat r;
    char cmd;
    char *buf = NULL;
    genarg arg;
    struct timeval timeout;
    int (*f) __P((genarg *));
    sfsistat (*fi_abort) __P((SMFICTX *));
    sfsistat (*fi_close) __P((SMFICTX *));

    arg.a_ctx = ctx;
    sd = ctx->ctx_sd;
    fi_abort = ctx->ctx_smfi->xxfi_abort;
    mi_clr_macros(ctx, 0);
    fix_stm(ctx);
    r = _SMFIS_NONE;
    do
    {
        /* call abort only if in a mail transaction */
        call_abort = ST_IN_MAIL(curstate);
        timeout.tv_sec = ctx->ctx_timeout;
        timeout.tv_usec = 0;
        if (mi_stop() == MILTER_ABRT)
        {
            if (ctx->ctx_dbg > 3)
                sm_dprintf("[%d] milter_abort\n",
                    (int) ctx->ctx_id);
            ret = MI_FAILURE;
            break;
        }

        /*
        **  Notice: buf is allocated by mi_rd_cmd() and it will
        **  usually be free()d after it has been used in f().
        **  However, if the function returns _SMFIS_KEEP then buf
        **  contains macros and will not be free()d.
        **  Hence r must be set to _SMFIS_NONE if a new buf is
        **  allocated to avoid problem with housekeeping, esp.
        **  if the code "break"s out of the loop.
        */

        r = _SMFIS_NONE;
        if ((buf = mi_rd_cmd(sd, &timeout, &cmd, &len,
                     ctx->ctx_smfi->xxfi_name)) == NULL &&
            cmd < SMFIC_VALIDCMD)
        {
            if (ctx->ctx_dbg > 5)
                sm_dprintf("[%d] mi_engine: mi_rd_cmd error (%x)\n",
                    (int) ctx->ctx_id, (int) cmd);

            /*
            **  eof is currently treated as failure ->
            **  abort() instead of close(), otherwise use:
            **  if (cmd != SMFIC_EOF)
            */

            ret = MI_FAILURE;
            break;
        }
        if (ctx->ctx_dbg > 4)
            sm_dprintf("[%d] got cmd '%c' len %d\n",
                (int) ctx->ctx_id, cmd, (int) len);
        for (i = 0; i < ncmds; i++)
        {
            if (cmd == cmds[i].cm_cmd)
                break;
        }
        if (i >= ncmds)
        {
            /* unknown command */
            if (ctx->ctx_dbg > 1)
                sm_dprintf("[%d] cmd '%c' unknown\n",
                    (int) ctx->ctx_id, cmd);
            ret = MI_FAILURE;
            break;
        }
        if ((f = cmds[i].cm_fct) == NULL)
        {
            /* stop for now */
            if (ctx->ctx_dbg > 1)
                sm_dprintf("[%d] cmd '%c' not impl\n",
                    (int) ctx->ctx_id, cmd);
            ret = MI_FAILURE;
            break;
        }

        /* is new state ok? */
        newstate = cmds[i].cm_next;
        if (ctx->ctx_dbg > 5)
            sm_dprintf("[%d] cur %x new %x nextmask %x\n",
                (int) ctx->ctx_id,
                curstate, newstate, next_states[curstate]);

        if (newstate != ST_NONE && !trans_ok(curstate, newstate))
        {
            if (ctx->ctx_dbg > 1)
                sm_dprintf("[%d] abort: cur %d (%x) new %d (%x) next %x\n",
                    (int) ctx->ctx_id,
                    curstate, MI_MASK(curstate),
                    newstate, MI_MASK(newstate),
                    next_states[curstate]);

            /* call abort only if in a mail transaction */
            if (fi_abort != NULL && call_abort)
                (void) (*fi_abort)(ctx);

            /*
            **  try to reach the new state from HELO
            **  if it can't be reached, ignore the command.
            */

            curstate = ST_HELO;
            if (!trans_ok(curstate, newstate))
            {
                if (buf != NULL)
                {
                    free(buf);
                    buf = NULL;
                }
                continue;
            }
        }
        arg.a_len = len;
        arg.a_buf = buf;
        if (newstate != ST_NONE)
        {
            curstate = newstate;
            ctx->ctx_state = curstate;
        }
        arg.a_idx = cmds[i].cm_macros;
        call_abort = ST_IN_MAIL(curstate);

        /* call function to deal with command */
        r = (*f)(&arg);
        if (r != _SMFIS_KEEP && buf != NULL)
        {
            free(buf);
            buf = NULL;
        }
        if (sendreply(r, sd, &timeout, ctx) != MI_SUCCESS)
        {
            ret = MI_FAILURE;
            break;
        }

        if (r == SMFIS_ACCEPT)
        {
            /* accept mail, no further actions taken */
            curstate = ST_HELO;
        }
        else if (r == SMFIS_REJECT || r == SMFIS_DISCARD ||
             r ==  SMFIS_TEMPFAIL)
        {
            /*
            **  further actions depend on current state
            **  if the IGNO bit is set: "ignore" the error,
            **  i.e., stay in the current state
            */
            if (!bitset(CT_IGNO, cmds[i].cm_todo))
                curstate = ST_HELO;
        }
        else if (r == _SMFIS_ABORT)
        {
            if (ctx->ctx_dbg > 5)
                sm_dprintf("[%d] function returned abort\n",
                    (int) ctx->ctx_id);
            ret = MI_FAILURE;
            break;
        }
    } while (!bitset(CT_END, cmds[i].cm_todo));

    if (ret != MI_SUCCESS)
    {
        /* call abort only if in a mail transaction */
        if (fi_abort != NULL && call_abort)
            (void) (*fi_abort)(ctx);
    }

    /* close must always be called */
    if ((fi_close = ctx->ctx_smfi->xxfi_close) != NULL)
        (void) (*fi_close)(ctx);
    if (r != _SMFIS_KEEP && buf != NULL)
        free(buf);
    mi_clr_macros(ctx, 0);
    return ret;
}
/*
**  SENDREPLY -- send a reply to the MTA
**
**  Parameters:
**      r -- reply code
**      sd -- socket descriptor
**      timeout_ptr -- (ptr to) timeout to use for sending
**      ctx -- context structure
**
**  Returns:
**      MI_SUCCESS/MI_FAILURE
*/

static int
sendreply(r, sd, timeout_ptr, ctx)
    sfsistat r;
    socket_t sd;
    struct timeval *timeout_ptr;
    SMFICTX_PTR ctx;
{
    int ret = MI_SUCCESS;

    switch (r)
    {
      case SMFIS_CONTINUE:
        ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_CONTINUE, NULL, 0);
        break;
      case SMFIS_TEMPFAIL:
      case SMFIS_REJECT:
        if (ctx->ctx_reply != NULL &&
            ((r == SMFIS_TEMPFAIL && *ctx->ctx_reply == '4') ||
             (r == SMFIS_REJECT && *ctx->ctx_reply == '5')))
        {
            ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_REPLYCODE,
                    ctx->ctx_reply,
                    strlen(ctx->ctx_reply) + 1);
            free(ctx->ctx_reply);
            ctx->ctx_reply = NULL;
        }
        else
        {
            ret = mi_wr_cmd(sd, timeout_ptr, r == SMFIS_REJECT ?
                    SMFIR_REJECT : SMFIR_TEMPFAIL, NULL, 0);
        }
        break;
      case SMFIS_DISCARD:
        ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_DISCARD, NULL, 0);
        break;
      case SMFIS_ACCEPT:
        ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_ACCEPT, NULL, 0);
        break;
      case _SMFIS_OPTIONS:
        {
            char buf[MILTER_OPTLEN];
            mi_int32 v;

            v = htonl(ctx->ctx_smfi->xxfi_version);
            (void) memcpy(&(buf[0]), (void *) &v, MILTER_LEN_BYTES);
            v = htonl(ctx->ctx_smfi->xxfi_flags);
            (void) memcpy(&(buf[MILTER_LEN_BYTES]), (void *) &v,
                      MILTER_LEN_BYTES);
            v = htonl(ctx->ctx_pflags);
            (void) memcpy(&(buf[MILTER_LEN_BYTES * 2]), (void *) &v,
                      MILTER_LEN_BYTES);
            ret = mi_wr_cmd(sd, timeout_ptr, SMFIC_OPTNEG, buf,
                       MILTER_OPTLEN);
        }
        break;
      default:  /* don't send a reply */
        break;
    }
    return ret;
}

/*
**  CLR_MACROS -- clear set of macros starting from a given index
**
**  Parameters:
**      ctx -- context structure
**      m -- index from which to clear all macros
**
**  Returns:
**      None.
*/
void
mi_clr_macros(ctx, m)
    SMFICTX_PTR ctx;
    int m;
{
    int i;

    for (i = m; i < MAX_MACROS_ENTRIES; i++)
    {
        if (ctx->ctx_mac_ptr[i] != NULL)
        {
            free(ctx->ctx_mac_ptr[i]);
            ctx->ctx_mac_ptr[i] = NULL;
        }
        if (ctx->ctx_mac_buf[i] != NULL)
        {
            free(ctx->ctx_mac_buf[i]);
            ctx->ctx_mac_buf[i] = NULL;
        }
    }
}
/*
**  ST_OPTIONNEG -- negotiate options
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      abort/send options/continue
*/

static int
st_optionneg(g)
    genarg *g;
{
    mi_int32 i, v;

    if (g == NULL || g->a_ctx->ctx_smfi == NULL)
        return SMFIS_CONTINUE;
    mi_clr_macros(g->a_ctx, g->a_idx + 1);

    /* check for minimum length */
    if (g->a_len < MILTER_OPTLEN)
    {
        smi_log(SMI_LOG_ERR,
            "%s: st_optionneg[%d]: len too short %d < %d",
            g->a_ctx->ctx_smfi->xxfi_name,
            (int) g->a_ctx->ctx_id, (int) g->a_len,
            MILTER_OPTLEN);
        return _SMFIS_ABORT;
    }

    (void) memcpy((void *) &i, (void *) &(g->a_buf[0]),
              MILTER_LEN_BYTES);
    v = ntohl(i);
    if (v < g->a_ctx->ctx_smfi->xxfi_version)
    {
        /* hard failure for now! */
        smi_log(SMI_LOG_ERR,
            "%s: st_optionneg[%d]: version mismatch MTA: %d < milter: %d",
            g->a_ctx->ctx_smfi->xxfi_name,
            (int) g->a_ctx->ctx_id, (int) v,
            g->a_ctx->ctx_smfi->xxfi_version);
        return _SMFIS_ABORT;
    }

    (void) memcpy((void *) &i, (void *) &(g->a_buf[MILTER_LEN_BYTES]),
              MILTER_LEN_BYTES);
    v = ntohl(i);

    /* no flags? set to default value for V1 actions */
    if (v == 0)
        v = SMFI_V1_ACTS;
    i = g->a_ctx->ctx_smfi->xxfi_flags;
    if ((v & i) != i)
    {
        smi_log(SMI_LOG_ERR,
            "%s: st_optionneg[%d]: 0x%x does not fulfill action requirements 0x%x",
            g->a_ctx->ctx_smfi->xxfi_name,
            (int) g->a_ctx->ctx_id, v, i);
        return _SMFIS_ABORT;
    }

    (void) memcpy((void *) &i, (void *) &(g->a_buf[MILTER_LEN_BYTES * 2]),
              MILTER_LEN_BYTES);
    v = ntohl(i);

    /* no flags? set to default value for V1 protocol */
    if (v == 0)
        v = SMFI_V1_PROT;
    i = g->a_ctx->ctx_pflags;
    if ((v & i) != i)
    {
        smi_log(SMI_LOG_ERR,
            "%s: st_optionneg[%d]: 0x%x does not fulfill protocol requirements 0x%x",
            g->a_ctx->ctx_smfi->xxfi_name,
            (int) g->a_ctx->ctx_id, v, i);
        return _SMFIS_ABORT;
    }

    return _SMFIS_OPTIONS;
}
/*
**  ST_CONNECTINFO -- receive connection information
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_connectinfo(g)
    genarg *g;
{
    size_t l;
    size_t i;
    char *s, family;
    unsigned short port = 0;
    _SOCK_ADDR sockaddr;
    sfsistat (*fi_connect) __P((SMFICTX *, char *, _SOCK_ADDR *));

    if (g == NULL)
        return _SMFIS_ABORT;
    mi_clr_macros(g->a_ctx, g->a_idx + 1);
    if (g->a_ctx->ctx_smfi == NULL ||
        (fi_connect = g->a_ctx->ctx_smfi->xxfi_connect) == NULL)
        return SMFIS_CONTINUE;

    s = g->a_buf;
    i = 0;
    l = g->a_len;
    while (s[i] != '\0' && i <= l)
        ++i;
    if (i + 1 >= l)
        return _SMFIS_ABORT;

    /* Move past trailing \0 in host string */
    i++;
    family = s[i++];
    (void) memset(&sockaddr, '\0', sizeof sockaddr);
    if (family != SMFIA_UNKNOWN)
    {
        if (i + sizeof port >= l)
        {
            smi_log(SMI_LOG_ERR,
                "%s: connect[%d]: wrong len %d >= %d",
                g->a_ctx->ctx_smfi->xxfi_name,
                (int) g->a_ctx->ctx_id, (int) i, (int) l);
            return _SMFIS_ABORT;
        }
        (void) memcpy((void *) &port, (void *) (s + i),
                  sizeof port);
        i += sizeof port;

        /* make sure string is terminated */
        if (s[l - 1] != '\0')
            return _SMFIS_ABORT;
# if NETINET
        if (family == SMFIA_INET)
        {
            if (inet_aton(s + i, (struct in_addr *) &sockaddr.sin.sin_addr)
                != 1)
            {
                smi_log(SMI_LOG_ERR,
                    "%s: connect[%d]: inet_aton failed",
                    g->a_ctx->ctx_smfi->xxfi_name,
                    (int) g->a_ctx->ctx_id);
                return _SMFIS_ABORT;
            }
            sockaddr.sa.sa_family = AF_INET;
            if (port > 0)
                sockaddr.sin.sin_port = port;
        }
        else
# endif /* NETINET */
# if NETINET6
        if (family == SMFIA_INET6)
        {
            if (mi_inet_pton(AF_INET6, s + i,
                     &sockaddr.sin6.sin6_addr) != 1)
            {
                smi_log(SMI_LOG_ERR,
                    "%s: connect[%d]: mi_inet_pton failed",
                    g->a_ctx->ctx_smfi->xxfi_name,
                    (int) g->a_ctx->ctx_id);
                return _SMFIS_ABORT;
            }
            sockaddr.sa.sa_family = AF_INET6;
            if (port > 0)
                sockaddr.sin6.sin6_port = port;
        }
        else
# endif /* NETINET6 */
# if NETUNIX
        if (family == SMFIA_UNIX)
        {
            if (sm_strlcpy(sockaddr.sunix.sun_path, s + i,
                sizeof sockaddr.sunix.sun_path) >=
                sizeof sockaddr.sunix.sun_path)
            {
                smi_log(SMI_LOG_ERR,
                    "%s: connect[%d]: path too long",
                    g->a_ctx->ctx_smfi->xxfi_name,
                    (int) g->a_ctx->ctx_id);
                return _SMFIS_ABORT;
            }
            sockaddr.sunix.sun_family = AF_UNIX;
        }
        else
# endif /* NETUNIX */
        {
            smi_log(SMI_LOG_ERR,
                "%s: connect[%d]: unknown family %d",
                g->a_ctx->ctx_smfi->xxfi_name,
                (int) g->a_ctx->ctx_id, family);
            return _SMFIS_ABORT;
        }
    }
    return (*fi_connect)(g->a_ctx, g->a_buf,
                 family != SMFIA_UNKNOWN ? &sockaddr : NULL);
}

/*
**  ST_EOH -- end of headers
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_eoh(g)
    genarg *g;
{
    sfsistat (*fi_eoh) __P((SMFICTX *));

    if (g == NULL)
        return _SMFIS_ABORT;
    if (g->a_ctx->ctx_smfi != NULL &&
        (fi_eoh = g->a_ctx->ctx_smfi->xxfi_eoh) != NULL)
        return (*fi_eoh)(g->a_ctx);
    return SMFIS_CONTINUE;
}

#if SMFI_VERSION > 3
/*
**  ST_DATA -- DATA command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_data(g)
    genarg *g;
{
    sfsistat (*fi_data) __P((SMFICTX *));

    if (g == NULL)
        return _SMFIS_ABORT;
    if (g->a_ctx->ctx_smfi != NULL &&
        (fi_data = g->a_ctx->ctx_smfi->xxfi_data) != NULL)
        return (*fi_data)(g->a_ctx);
    return SMFIS_CONTINUE;
}
#endif /* SMFI_VERSION > 3 */

/*
**  ST_HELO -- helo/ehlo command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/
static int
st_helo(g)
    genarg *g;
{
    sfsistat (*fi_helo) __P((SMFICTX *, char *));

    if (g == NULL)
        return _SMFIS_ABORT;
    mi_clr_macros(g->a_ctx, g->a_idx + 1);
    if (g->a_ctx->ctx_smfi != NULL &&
        (fi_helo = g->a_ctx->ctx_smfi->xxfi_helo) != NULL)
    {
        /* paranoia: check for terminating '\0' */
        if (g->a_len == 0 || g->a_buf[g->a_len - 1] != '\0')
            return MI_FAILURE;
        return (*fi_helo)(g->a_ctx, g->a_buf);
    }
    return SMFIS_CONTINUE;
}
/*
**  ST_HEADER -- header line
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_header(g)
    genarg *g;
{
    char *hf, *hv;
    sfsistat (*fi_header) __P((SMFICTX *, char *, char *));

    if (g == NULL)
        return _SMFIS_ABORT;
    if (g->a_ctx->ctx_smfi == NULL ||
        (fi_header = g->a_ctx->ctx_smfi->xxfi_header) == NULL)
        return SMFIS_CONTINUE;
    if (dec_arg2(g->a_buf, g->a_len, &hf, &hv) == MI_SUCCESS)
        return (*fi_header)(g->a_ctx, hf, hv);
    else
        return _SMFIS_ABORT;
}

#define ARGV_FCT(lf, rf, idx)                   \
    char **argv;                        \
    sfsistat (*lf) __P((SMFICTX *, char **));       \
    int r;                          \
                                \
    if (g == NULL)                      \
        return _SMFIS_ABORT;                \
    mi_clr_macros(g->a_ctx, g->a_idx + 1);          \
    if (g->a_ctx->ctx_smfi == NULL ||           \
        (lf = g->a_ctx->ctx_smfi->rf) == NULL)      \
        return SMFIS_CONTINUE;              \
    if ((argv = dec_argv(g->a_buf, g->a_len)) == NULL)  \
        return _SMFIS_ABORT;                \
    r = (*lf)(g->a_ctx, argv);              \
    free(argv);                     \
    return r;

/*
**  ST_SENDER -- MAIL FROM command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_sender(g)
    genarg *g;
{
    ARGV_FCT(fi_envfrom, xxfi_envfrom, CI_MAIL)
}
/*
**  ST_RCPT -- RCPT TO command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_rcpt(g)
    genarg *g;
{
    ARGV_FCT(fi_envrcpt, xxfi_envrcpt, CI_RCPT)
}

#if SMFI_VERSION > 2
/*
**  ST_UNKNOWN -- unrecognized or unimplemented command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_unknown(g)
    genarg *g;
{
    sfsistat (*fi_unknown) __P((SMFICTX *, char *));

    if (g == NULL)
        return _SMFIS_ABORT;
    mi_clr_macros(g->a_ctx, g->a_idx + 1);
    if (g->a_ctx->ctx_smfi != NULL &&
        (fi_unknown = g->a_ctx->ctx_smfi->xxfi_unknown) != NULL)
        return (*fi_unknown)(g->a_ctx, g->a_buf);
    return SMFIS_CONTINUE;
}
#endif /* SMFI_VERSION > 2 */

/*
**  ST_MACROS -- deal with macros received from the MTA
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue/keep
**
**  Side effects:
**      set pointer in macro array to current values.
*/

static int
st_macros(g)
    genarg *g;
{
    int i;
    char **argv;

    if (g == NULL || g->a_len < 1)
        return _SMFIS_FAIL;
    if ((argv = dec_argv(g->a_buf + 1, g->a_len - 1)) == NULL)
        return _SMFIS_FAIL;
    switch (g->a_buf[0])
    {
      case SMFIC_CONNECT:
        i = CI_CONN;
        break;
      case SMFIC_HELO:
        i = CI_HELO;
        break;
      case SMFIC_MAIL:
        i = CI_MAIL;
        break;
      case SMFIC_RCPT:
        i = CI_RCPT;
        break;
      case SMFIC_BODYEOB:
        i = CI_EOM;
        break;
      default:
        free(argv);
        return _SMFIS_FAIL;
    }
    if (g->a_ctx->ctx_mac_ptr[i] != NULL)
        free(g->a_ctx->ctx_mac_ptr[i]);
    if (g->a_ctx->ctx_mac_buf[i] != NULL)
        free(g->a_ctx->ctx_mac_buf[i]);
    g->a_ctx->ctx_mac_ptr[i] = argv;
    g->a_ctx->ctx_mac_buf[i] = g->a_buf;
    return _SMFIS_KEEP;
}
/*
**  ST_QUIT -- quit command
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      noreply
*/

/* ARGSUSED */
static int
st_quit(g)
    genarg *g;
{
    return _SMFIS_NOREPLY;
}
/*
**  ST_BODYCHUNK -- deal with a piece of the mail body
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
*/

static int
st_bodychunk(g)
    genarg *g;
{
    sfsistat (*fi_body) __P((SMFICTX *, unsigned char *, size_t));

    if (g == NULL)
        return _SMFIS_ABORT;
    if (g->a_ctx->ctx_smfi != NULL &&
        (fi_body = g->a_ctx->ctx_smfi->xxfi_body) != NULL)
        return (*fi_body)(g->a_ctx, (unsigned char *)g->a_buf,
                  g->a_len);
    return SMFIS_CONTINUE;
}
/*
**  ST_BODYEND -- deal with the last piece of the mail body
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      continue or filter-specified value
**
**  Side effects:
**      sends a reply for the body part (if non-empty).
*/

static int
st_bodyend(g)
    genarg *g;
{
    sfsistat r;
    sfsistat (*fi_body) __P((SMFICTX *, unsigned char *, size_t));
    sfsistat (*fi_eom) __P((SMFICTX *));

    if (g == NULL)
        return _SMFIS_ABORT;
    r = SMFIS_CONTINUE;
    if (g->a_ctx->ctx_smfi != NULL)
    {
        if ((fi_body = g->a_ctx->ctx_smfi->xxfi_body) != NULL &&
            g->a_len > 0)
        {
            socket_t sd;
            struct timeval timeout;

            timeout.tv_sec = g->a_ctx->ctx_timeout;
            timeout.tv_usec = 0;
            sd = g->a_ctx->ctx_sd;
            r = (*fi_body)(g->a_ctx, (unsigned char *)g->a_buf,
                       g->a_len);
            if (r != SMFIS_CONTINUE &&
                sendreply(r, sd, &timeout, g->a_ctx) != MI_SUCCESS)
                return _SMFIS_ABORT;
        }
    }
    if (r == SMFIS_CONTINUE &&
        (fi_eom = g->a_ctx->ctx_smfi->xxfi_eom) != NULL)
        return (*fi_eom)(g->a_ctx);
    return r;
}
/*
**  ST_ABORTFCT -- deal with aborts
**
**  Parameters:
**      g -- generic argument structure
**
**  Returns:
**      abort or filter-specified value
*/

static int
st_abortfct(g)
    genarg *g;
{
    sfsistat (*fi_abort) __P((SMFICTX *));

    if (g == NULL)
        return _SMFIS_ABORT;
    if (g != NULL && g->a_ctx->ctx_smfi != NULL &&
        (fi_abort = g->a_ctx->ctx_smfi->xxfi_abort) != NULL)
        (void) (*fi_abort)(g->a_ctx);
    return _SMFIS_NOREPLY;
}
/*
**  TRANS_OK -- is the state transition ok?
**
**  Parameters:
**      old -- old state
**      new -- new state
**
**  Returns:
**      state transition ok
*/

static bool
trans_ok(old, new)
    int old, new;
{
    int s, n;

    s = old;
    if (s >= SIZE_NEXT_STATES)
        return false;
    do
    {
        /* is this state transition allowed? */
        if ((MI_MASK(new) & next_states[s]) != 0)
            return true;

        /*
        **  no: try next state;
        **  this works since the relevant states are ordered
        **  strict sequentially
        */

        n = s + 1;
        if (n >= SIZE_NEXT_STATES)
            return false;

        /*
        **  can we actually "skip" this state?
        **  see fix_stm() which sets this bit for those
        **  states which the filter program is not interested in
        */

        if (bitset(NX_SKIP, next_states[n]))
            s = n;
        else
            return false;
    } while (s < SIZE_NEXT_STATES);
    return false;
}
/*
**  FIX_STM -- add "skip" bits to the state transition table
**
**  Parameters:
**      ctx -- context structure
**
**  Returns:
**      None.
**
**  Side effects:
**      may change state transition table.
*/

static void
fix_stm(ctx)
    SMFICTX_PTR ctx;
{
    unsigned long fl;

    if (ctx == NULL || ctx->ctx_smfi == NULL)
        return;
    fl = ctx->ctx_pflags;
    if (bitset(SMFIP_NOCONNECT, fl))
        next_states[ST_CONN] |= NX_SKIP;
    if (bitset(SMFIP_NOHELO, fl))
        next_states[ST_HELO] |= NX_SKIP;
    if (bitset(SMFIP_NOMAIL, fl))
        next_states[ST_MAIL] |= NX_SKIP;
    if (bitset(SMFIP_NORCPT, fl))
        next_states[ST_RCPT] |= NX_SKIP;
    if (bitset(SMFIP_NOHDRS, fl))
        next_states[ST_HDRS] |= NX_SKIP;
    if (bitset(SMFIP_NOEOH, fl))
        next_states[ST_EOHS] |= NX_SKIP;
    if (bitset(SMFIP_NOBODY, fl))
        next_states[ST_BODY] |= NX_SKIP;
}
/*
**  DEC_ARGV -- split a buffer into a list of strings, NULL terminated
**
**  Parameters:
**      buf -- buffer with several strings
**      len -- length of buffer
**
**  Returns:
**      array of pointers to the individual strings
*/

static char **
dec_argv(buf, len)
    char *buf;
    size_t len;
{
    char **s;
    size_t i;
    int elem, nelem;

    nelem = 0;
    for (i = 0; i < len; i++)
    {
        if (buf[i] == '\0')
            ++nelem;
    }
    if (nelem == 0)
        return NULL;

    /* last entry is only for the name */
    s = (char **)malloc((nelem + 1) * (sizeof *s));
    if (s == NULL)
        return NULL;
    s[0] = buf;
    for (i = 0, elem = 0; i < len && elem < nelem; i++)
    {
        if (buf[i] == '\0')
        {
            ++elem;
            if (i + 1 >= len)
                s[elem] = NULL;
            else
                s[elem] = &(buf[i + 1]);
        }
    }

    /* overwrite last entry (already done above, just paranoia) */
    s[elem] = NULL;
    return s;
}
/*
**  DEC_ARG2 -- split a buffer into two strings
**
**  Parameters:
**      buf -- buffer with two strings
**      len -- length of buffer
**      s1,s2 -- pointer to result strings
**
**  Returns:
**      MI_FAILURE/MI_SUCCESS
*/

static int
dec_arg2(buf, len, s1, s2)
    char *buf;
    size_t len;
    char **s1;
    char **s2;
{
    size_t i;

    /* paranoia: check for terminating '\0' */
    if (len == 0 || buf[len - 1] != '\0')
        return MI_FAILURE;
    *s1 = buf;
    for (i = 1; i < len && buf[i] != '\0'; i++)
        continue;
    if (i >= len - 1)
        return MI_FAILURE;
    *s2 = buf + i + 1;
    return MI_SUCCESS;
}
/*
**  SENDOK -- is it ok for the filter to send stuff to the MTA?
**
**  Parameters:
**      ctx -- context structure
**      flag -- flag to check
**
**  Returns:
**      sending allowed (in current state)
*/

bool
mi_sendok(ctx, flag)
    SMFICTX_PTR ctx;
    int flag;
{
    if (ctx == NULL || ctx->ctx_smfi == NULL)
        return false;

    /* did the milter request this operation? */
    if (flag != 0 && !bitset(flag, ctx->ctx_smfi->xxfi_flags))
        return false;

    /* are we in the correct state? It must be "End of Message". */
    return ctx->ctx_state == ST_ENDM;
}