/*
 *  Copyright (c) 1999-2004, 2006-2008 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.
 *
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: engine.c,v 8.166 2009/11/06 00:57:07 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  /* last command of session, stop 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_DATA         4
#define CI_EOM          5
#define CI_EOH          6
#define CI_LAST         CI_EOH
#if CI_LAST < CI_DATA
ERROR: do not compile with CI_LAST < CI_DATA
#endif
#if CI_LAST < CI_EOM
ERROR: do not compile with CI_LAST < CI_EOM
#endif
#if CI_LAST < CI_EOH
ERROR: do not compile with CI_LAST < CI_EOH
#endif
#if CI_LAST < CI_ENVRCPT
ERROR: do not compile with CI_LAST < CI_ENVRCPT
#endif
#if CI_LAST < CI_ENVFROM
ERROR: do not compile with CI_LAST < CI_ENVFROM
#endif
#if CI_LAST < CI_HELO
ERROR: do not compile with CI_LAST < CI_HELO
#endif
#if CI_LAST < CI_CONNECT
ERROR: do not compile with CI_LAST < CI_CONNECT
#endif
#if CI_LAST >= MAX_MACROS_ENTRIES
ERROR: do not compile with CI_LAST >= 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 *));
static int      st_unknown __P((genarg *));
static int      st_data __P((genarg *));
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 **));
static void     mi_clr_symlist __P((SMFICTX_PTR));

#if _FFR_WORKERS_POOL
static bool     mi_rd_socket_ready __P((int));
#endif /* _FFR_WORKERS_POOL */

/* 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_Q_NC 14      /* quit, new connection follows */
#define ST_LAST ST_Q_NC /* last valid state */
#define ST_SKIP 16      /* 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) | \
                MI_MASK(ST_Q_NC))
#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) | MI_MASK(ST_Q_NC))
#define NX_Q_NC (MI_MASK(ST_CONN) | MI_MASK(ST_UNKN))
#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
        , NX_Q_NC
};

#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_EOH,  st_eoh         }
, {SMFIC_QUIT,  CM_ARG0, ST_QUIT,  CT_END,      CI_NONE, st_quit        }
, {SMFIC_DATA,  CM_ARG0, ST_DATA,  CT_CONT,     CI_DATA, st_data        }
, {SMFIC_RCPT,  CM_ARGV, ST_RCPT,  CT_IGNO,     CI_RCPT, st_rcpt        }
, {SMFIC_UNKNOWN, CM_ARG1, ST_UNKN,  CT_IGNO,   CI_NONE, st_unknown     }
, {SMFIC_QUIT_NC, CM_ARG0, ST_Q_NC,  CT_CONT,   CI_NONE, st_quit        }
};

/*
**  Additional (internal) reply codes;
**  must be coordinated wit libmilter/mfapi.h
*/

#define _SMFIS_KEEP     20
#define _SMFIS_ABORT    21
#define _SMFIS_OPTIONS  22
#define _SMFIS_NOREPLY  SMFIS_NOREPLY
#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;
#if _FFR_WORKERS_POOL
        curstate = ctx->ctx_state;
        if (curstate == ST_INIT)
        {
                mi_clr_macros(ctx, 0);
                fix_stm(ctx);
        }
#else   /* _FFR_WORKERS_POOL */
        mi_clr_macros(ctx, 0);
        fix_stm(ctx);
#endif  /* _FFR_WORKERS_POOL */
        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("[%ld] milter_abort\n",
                                        (long) 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.
                */

#if _FFR_WORKERS_POOL
                /* Is the socket ready to be read ??? */
                if (!mi_rd_socket_ready(sd))
                {
                        ret = MI_CONTINUE;
                        break;
                }
#endif  /* _FFR_WORKERS_POOL */

                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("[%ld] mi_engine: mi_rd_cmd error (%x)\n",
                                        (long) 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("[%ld] got cmd '%c' len %d\n",
                                (long) 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("[%ld] cmd '%c' unknown\n",
                                        (long) 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("[%ld] cmd '%c' not impl\n",
                                        (long) ctx->ctx_id, cmd);
                        ret = MI_FAILURE;
                        break;
                }

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

                if (newstate != ST_NONE && !trans_ok(curstate, newstate))
                {
                        if (ctx->ctx_dbg > 1)
                                sm_dprintf("[%ld] abort: cur %d (%x) new %d (%x) next %x\n",
                                        (long) 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 */
                MI_MONITOR_BEGIN(ctx, cmd);
                r = (*f)(&arg);
                MI_MONITOR_END(ctx, cmd);
                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("[%ld] function returned abort\n",
                                        (long) ctx->ctx_id);
                        ret = MI_FAILURE;
                        break;
                }
        } while (!bitset(CT_END, cmds[i].cm_todo));

        ctx->ctx_state = curstate;

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

        /* has close been called? */
        if (ctx->ctx_state != ST_QUIT
#if _FFR_WORKERS_POOL
           && ret != MI_CONTINUE
#endif /* _FFR_WORKERS_POOL */
           )
        {
                if ((fi_close = ctx->ctx_smfi->xxfi_close) != NULL)
                        (void) (*fi_close)(ctx);
        }
        if (r != _SMFIS_KEEP && buf != NULL)
                free(buf);
#if !_FFR_WORKERS_POOL
        mi_clr_macros(ctx, 0);
#endif /* _FFR_WORKERS_POOL */
        return ret;
}

static size_t milter_addsymlist __P((SMFICTX_PTR, char *, char **));

static size_t
milter_addsymlist(ctx, buf, newbuf)
        SMFICTX_PTR ctx;
        char *buf;
        char **newbuf;
{
        size_t len;
        int i;
        mi_int32 v;
        char *buffer;

        SM_ASSERT(ctx != NULL);
        SM_ASSERT(buf != NULL);
        SM_ASSERT(newbuf != NULL);
        len = 0;
        for (i = 0; i < MAX_MACROS_ENTRIES; i++)
        {
                if (ctx->ctx_mac_list[i] != NULL)
                {
                        len += strlen(ctx->ctx_mac_list[i]) + 1 +
                                MILTER_LEN_BYTES;
                }
        }
        if (len > 0)
        {
                size_t offset;

                SM_ASSERT(len + MILTER_OPTLEN > len);
                len += MILTER_OPTLEN;
                buffer = malloc(len);
                if (buffer != NULL)
                {
                        (void) memcpy(buffer, buf, MILTER_OPTLEN);
                        offset = MILTER_OPTLEN;
                        for (i = 0; i < MAX_MACROS_ENTRIES; i++)
                        {
                                size_t l;

                                if (ctx->ctx_mac_list[i] == NULL)
                                        continue;

                                SM_ASSERT(offset + MILTER_LEN_BYTES < len);
                                v = htonl(i);
                                (void) memcpy(buffer + offset, (void *) &v,
                                                MILTER_LEN_BYTES);
                                offset += MILTER_LEN_BYTES;
                                l = strlen(ctx->ctx_mac_list[i]) + 1;
                                SM_ASSERT(offset + l <= len);
                                (void) memcpy(buffer + offset,
                                                ctx->ctx_mac_list[i], l);
                                offset += l;
                        }
                }
                else
                {
                        /* oops ... */
                }
        }
        else
        {
                len = MILTER_OPTLEN;
                buffer = buf;
        }
        *newbuf = buffer;
        return len;
}

/*
**  GET_NR_BIT -- get "no reply" bit matching state
**
**      Parameters:
**              state -- current protocol stage
**
**      Returns:
**              0: no matching bit
**              >0: the matching "no reply" bit
*/

static unsigned long get_nr_bit __P((int));

static unsigned long
get_nr_bit(state)
        int state;
{
        unsigned long bit;

        switch (state)
        {
          case ST_CONN:
                bit = SMFIP_NR_CONN;
                break;
          case ST_HELO:
                bit = SMFIP_NR_HELO;
                break;
          case ST_MAIL:
                bit = SMFIP_NR_MAIL;
                break;
          case ST_RCPT:
                bit = SMFIP_NR_RCPT;
                break;
          case ST_DATA:
                bit = SMFIP_NR_DATA;
                break;
          case ST_UNKN:
                bit = SMFIP_NR_UNKN;
                break;
          case ST_HDRS:
                bit = SMFIP_NR_HDR;
                break;
          case ST_EOHS:
                bit = SMFIP_NR_EOH;
                break;
          case ST_BODY:
                bit = SMFIP_NR_BODY;
                break;
          default:
                bit = 0;
                break;
        }
        return bit;
}

/*
**  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;
        unsigned long bit;

        ret = MI_SUCCESS;

        bit = get_nr_bit(ctx->ctx_state);
        if (bit != 0 && (ctx->ctx_pflags & bit) != 0 && r != SMFIS_NOREPLY)
        {
                if (r >= SMFIS_CONTINUE && r < _SMFIS_KEEP)
                {
                        /* milter said it wouldn't reply, but it lied... */
                        smi_log(SMI_LOG_ERR,
                                "%s: milter claimed not to reply in state %d but did anyway %d\n",
                                ctx->ctx_smfi->xxfi_name,
                                ctx->ctx_state, r);

                }

                /*
                **  Force specified behavior, otherwise libmilter
                **  and MTA will fail to communicate properly.
                */

                switch (r)
                {
                  case SMFIS_CONTINUE:
                  case SMFIS_TEMPFAIL:
                  case SMFIS_REJECT:
                  case SMFIS_DISCARD:
                  case SMFIS_ACCEPT:
                  case SMFIS_SKIP:
                  case _SMFIS_OPTIONS:
                        r = SMFIS_NOREPLY;
                        break;
                }
        }

        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_SKIP:
                ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_SKIP, NULL, 0);
                break;
          case _SMFIS_OPTIONS:
                {
                        mi_int32 v;
                        size_t len;
                        char *buffer;
                        char buf[MILTER_OPTLEN];

                        v = htonl(ctx->ctx_prot_vers2mta);
                        (void) memcpy(&(buf[0]), (void *) &v,
                                      MILTER_LEN_BYTES);
                        v = htonl(ctx->ctx_aflags);
                        (void) memcpy(&(buf[MILTER_LEN_BYTES]), (void *) &v,
                                      MILTER_LEN_BYTES);
                        v = htonl(ctx->ctx_pflags2mta);
                        (void) memcpy(&(buf[MILTER_LEN_BYTES * 2]),
                                      (void *) &v, MILTER_LEN_BYTES);
                        len = milter_addsymlist(ctx, buf, &buffer);
                        if (buffer != NULL)
                                ret = mi_wr_cmd(sd, timeout_ptr, SMFIC_OPTNEG,
                                                buffer, len);
                        else
                                ret = MI_FAILURE;
                }
                break;
          case SMFIS_NOREPLY:
                if (bit != 0 &&
                    (ctx->ctx_pflags & bit) != 0 &&
                    (ctx->ctx_mta_pflags & bit) == 0)
                {
                        /*
                        **  milter doesn't want to send a reply,
                        **  but the MTA doesn't have that feature: fake it.
                        */

                        ret = mi_wr_cmd(sd, timeout_ptr, SMFIR_CONTINUE, NULL,
                                        0);
                }
                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;
                }
        }
}

/*
**  MI_CLR_SYMLIST -- clear list of macros
**
**      Parameters:
**              ctx -- context structure
**
**      Returns:
**              None.
*/

static void
mi_clr_symlist(ctx)
        SMFICTX *ctx;
{
        int i;

        SM_ASSERT(ctx != NULL);
        for (i = SMFIM_FIRST; i <= SMFIM_LAST; i++)
        {
                if (ctx->ctx_mac_list[i] != NULL)
                {
                        free(ctx->ctx_mac_list[i]);
                        ctx->ctx_mac_list[i] = NULL;
                }
        }
}

/*
**  MI_CLR_CTX -- clear context
**
**      Parameters:
**              ctx -- context structure
**
**      Returns:
**              None.
*/

void
mi_clr_ctx(ctx)
        SMFICTX *ctx;
{
        SM_ASSERT(ctx != NULL);
        if (ValidSocket(ctx->ctx_sd))
        {
                (void) closesocket(ctx->ctx_sd);
                ctx->ctx_sd = INVALID_SOCKET;
        }
        if (ctx->ctx_reply != NULL)
        {
                free(ctx->ctx_reply);
                ctx->ctx_reply = NULL;
        }
        if (ctx->ctx_privdata != NULL)
        {
                smi_log(SMI_LOG_WARN,
                        "%s: private data not NULL",
                        ctx->ctx_smfi->xxfi_name);
        }
        mi_clr_macros(ctx, 0);
        mi_clr_symlist(ctx);
        free(ctx);
}

/*
**  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, fake_pflags, internal_pflags;
        SMFICTX_PTR ctx;
#if _FFR_MILTER_CHECK
        bool testmode = false;
#endif /* _FFR_MILTER_CHECK */
        int (*fi_negotiate) __P((SMFICTX *,
                                        unsigned long, unsigned long,
                                        unsigned long, unsigned long,
                                        unsigned long *, unsigned long *,
                                        unsigned long *, unsigned long *));

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

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

        /* protocol version */
        (void) memcpy((void *) &i, (void *) &(g->a_buf[0]), MILTER_LEN_BYTES);
        v = ntohl(i);

#define SMFI_PROT_VERSION_MIN   2

        /* check for minimum version */
        if (v < SMFI_PROT_VERSION_MIN)
        {
                smi_log(SMI_LOG_ERR,
                        "%s: st_optionneg[%ld]: protocol version too old %d < %d",
                        ctx->ctx_smfi->xxfi_name,
                        (long) ctx->ctx_id, v, SMFI_PROT_VERSION_MIN);
                return _SMFIS_ABORT;
        }
        ctx->ctx_mta_prot_vers = v;
        if (ctx->ctx_prot_vers < ctx->ctx_mta_prot_vers)
                ctx->ctx_prot_vers2mta = ctx->ctx_prot_vers;
        else
                ctx->ctx_prot_vers2mta = ctx->ctx_mta_prot_vers;

        (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;
        ctx->ctx_mta_aflags = v;        /* MTA action flags */

        internal_pflags = 0;
        (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;
#if _FFR_MDS_NEGOTIATE
        else if (ctx->ctx_smfi->xxfi_version >= SMFI_VERSION_MDS)
        {
                /*
                **  Allow changing the size only if milter is compiled
                **  against a version that supports this.
                **  If a milter is dynamically linked against a newer
                **  libmilter version, we don't want to "surprise"
                **  it with a larger buffer as it may rely on it
                **  even though it is not documented as a limit.
                */

                if (bitset(SMFIP_MDS_1M, v))
                {
                        internal_pflags |= SMFIP_MDS_1M;
                        (void) smfi_setmaxdatasize(MILTER_MDS_1M);
                }
                else if (bitset(SMFIP_MDS_256K, v))
                {
                        internal_pflags |= SMFIP_MDS_256K;
                        (void) smfi_setmaxdatasize(MILTER_MDS_256K);
                }
        }
# if 0
        /* don't log this for now... */
        else if (ctx->ctx_smfi->xxfi_version < SMFI_VERSION_MDS &&
                 bitset(SMFIP_MDS_1M|SMFIP_MDS_256K, v))
        {
                smi_log(SMI_LOG_WARN,
                        "%s: st_optionneg[%ld]: milter version=%X, trying flags=%X",
                        ctx->ctx_smfi->xxfi_name,
                        (long) ctx->ctx_id, ctx->ctx_smfi->xxfi_version, v);
        }
# endif /* 0 */
#endif /* _FFR_MDS_NEGOTIATE */

        /*
        **  MTA protocol flags.
        **  We pass the internal flags to the milter as "read only",
        **  i.e., a milter can read them so it knows which size
        **  will be used, but any changes by a milter will be ignored
        **  (see below, search for SMFI_INTERNAL).
        */

        ctx->ctx_mta_pflags = (v & ~SMFI_INTERNAL) | internal_pflags;

        /*
        **  Copy flags from milter struct into libmilter context;
        **  this variable will be used later on to check whether
        **  the MTA "actions" can fulfill the milter requirements,
        **  but it may be overwritten by the negotiate callback.
        */

        ctx->ctx_aflags = ctx->ctx_smfi->xxfi_flags;
        fake_pflags = SMFIP_NR_CONN
                        |SMFIP_NR_HELO
                        |SMFIP_NR_MAIL
                        |SMFIP_NR_RCPT
                        |SMFIP_NR_DATA
                        |SMFIP_NR_UNKN
                        |SMFIP_NR_HDR
                        |SMFIP_NR_EOH
                        |SMFIP_NR_BODY
                        ;

        if (g->a_ctx->ctx_smfi != NULL &&
            g->a_ctx->ctx_smfi->xxfi_version > 4 &&
            (fi_negotiate = g->a_ctx->ctx_smfi->xxfi_negotiate) != NULL)
        {
                int r;
                unsigned long m_aflags, m_pflags, m_f2, m_f3;

                /*
                **  let milter decide whether the features offered by the
                **  MTA are "good enough".
                **  Notes:
                **  - libmilter can "fake" some features (e.g., SMFIP_NR_HDR)
                **  - m_f2, m_f3 are for future extensions
                */

                m_f2 = m_f3 = 0;
                m_aflags = ctx->ctx_mta_aflags;
                m_pflags = ctx->ctx_pflags;
                if ((SMFIP_SKIP & ctx->ctx_mta_pflags) != 0)
                        m_pflags |= SMFIP_SKIP;
                r = fi_negotiate(g->a_ctx,
                                ctx->ctx_mta_aflags,
                                ctx->ctx_mta_pflags|fake_pflags,
                                0, 0,
                                &m_aflags, &m_pflags, &m_f2, &m_f3);

#if _FFR_MILTER_CHECK
                testmode = bitset(SMFIP_TEST, m_pflags);
                if (testmode)
                        m_pflags &= ~SMFIP_TEST;
#endif /* _FFR_MILTER_CHECK */

                /*
                **  Types of protocol flags (pflags):
                **  1. do NOT send protocol step X
                **  2. MTA can do/understand something extra (SKIP,
                **      send unknown RCPTs)
                **  3. MTA can deal with "no reply" for various protocol steps
                **  Note: this mean that it isn't possible to simply set all
                **      flags to get "everything":
                **      setting a flag of type 1 turns off a step
                **              (it should be the other way around:
                **              a flag means a protocol step can be sent)
                **      setting a flag of type 3 requires that milter
                **      never sends a reply for the corresponding step.
                **  Summary: the "negation" of protocol flags is causing
                **      problems, but at least for type 3 there is no simple
                **      solution.
                **
                **  What should "all options" mean?
                **  send all protocol steps _except_ those for which there is
                **      no callback (currently registered in ctx_pflags)
                **  expect SKIP as return code?         Yes
                **  send unknown RCPTs?                 No,
                **                              must be explicitly requested?
                **  "no reply" for some protocol steps? No,
                **                              must be explicitly requested.
                */

                if (SMFIS_ALL_OPTS == r)
                {
                        ctx->ctx_aflags = ctx->ctx_mta_aflags;
                        ctx->ctx_pflags2mta = ctx->ctx_pflags;
                        if ((SMFIP_SKIP & ctx->ctx_mta_pflags) != 0)
                                ctx->ctx_pflags2mta |= SMFIP_SKIP;
                }
                else if (r != SMFIS_CONTINUE)
                {
                        smi_log(SMI_LOG_ERR,
                                "%s: st_optionneg[%ld]: xxfi_negotiate returned %d (protocol options=0x%lx, actions=0x%lx)",
                                ctx->ctx_smfi->xxfi_name,
                                (long) ctx->ctx_id, r, ctx->ctx_mta_pflags,
                                ctx->ctx_mta_aflags);
                        return _SMFIS_ABORT;
                }
                else
                {
                        ctx->ctx_aflags = m_aflags;
                        ctx->ctx_pflags = m_pflags;
                        ctx->ctx_pflags2mta = m_pflags;
                }

                /* check whether some flags need to be "faked" */
                i = ctx->ctx_pflags2mta;
                if ((ctx->ctx_mta_pflags & i) != i)
                {
                        unsigned int idx;
                        unsigned long b;

                        /*
                        **  If some behavior can be faked (set in fake_pflags),
                        **  but the MTA doesn't support it, then unset
                        **  that flag in the value that is sent to the MTA.
                        */

                        for (idx = 0; idx < 32; idx++)
                        {
                                b = 1 << idx;
                                if ((ctx->ctx_mta_pflags & b) != b &&
                                    (fake_pflags & b) == b)
                                        ctx->ctx_pflags2mta &= ~b;
                        }
                }
        }
        else
        {
                /*
                **  Set the protocol flags based on the values determined
                **  in mi_listener() which checked the defined callbacks.
                */

                ctx->ctx_pflags2mta = ctx->ctx_pflags;
        }

        /* check whether actions and protocol requirements can be satisfied */
        i = ctx->ctx_aflags;
        if ((i & ctx->ctx_mta_aflags) != i)
        {
                smi_log(SMI_LOG_ERR,
                        "%s: st_optionneg[%ld]: 0x%lx does not fulfill action requirements 0x%x",
                        ctx->ctx_smfi->xxfi_name,
                        (long) ctx->ctx_id, ctx->ctx_mta_aflags, i);
                return _SMFIS_ABORT;
        }

        i = ctx->ctx_pflags2mta;
        if ((ctx->ctx_mta_pflags & i) != i)
        {
                /*
                **  Older MTAs do not support some protocol steps.
                **  As this protocol is a bit "wierd" (it asks for steps
                **  NOT to be taken/sent) we have to check whether we
                **  should turn off those "negative" requests.
                **  Currently these are only SMFIP_NODATA and SMFIP_NOUNKNOWN.
                */

                if (bitset(SMFIP_NODATA, ctx->ctx_pflags2mta) &&
                    !bitset(SMFIP_NODATA, ctx->ctx_mta_pflags))
                        ctx->ctx_pflags2mta &= ~SMFIP_NODATA;
                if (bitset(SMFIP_NOUNKNOWN, ctx->ctx_pflags2mta) &&
                    !bitset(SMFIP_NOUNKNOWN, ctx->ctx_mta_pflags))
                        ctx->ctx_pflags2mta &= ~SMFIP_NOUNKNOWN;
                i = ctx->ctx_pflags2mta;
        }

        if ((ctx->ctx_mta_pflags & i) != i)
        {
                smi_log(SMI_LOG_ERR,
                        "%s: st_optionneg[%ld]: 0x%lx does not fulfill protocol requirements 0x%x",
                        ctx->ctx_smfi->xxfi_name,
                        (long) ctx->ctx_id, ctx->ctx_mta_pflags, i);
                return _SMFIS_ABORT;
        }
        fix_stm(ctx);

        if (ctx->ctx_dbg > 3)
                sm_dprintf("[%ld] milter_negotiate:"
                        " mta_actions=0x%lx, mta_flags=0x%lx"
                        " actions=0x%lx, flags=0x%lx\n"
                        , (long) ctx->ctx_id
                        , ctx->ctx_mta_aflags, ctx->ctx_mta_pflags
                        , ctx->ctx_aflags, ctx->ctx_pflags);

#if _FFR_MILTER_CHECK
        if (ctx->ctx_dbg > 3)
                sm_dprintf("[%ld] milter_negotiate:"
                        " testmode=%d, pflags2mta=%X, internal_pflags=%X\n"
                        , (long) ctx->ctx_id, testmode
                        , ctx->ctx_pflags2mta, internal_pflags);

        /* in test mode: take flags without further modifications */
        if (!testmode)
                /* Warning: check statement below! */
#endif /* _FFR_MILTER_CHECK */

        /*
        **  Remove the internal flags that might have been set by a milter
        **  and set only those determined above.
        */

        ctx->ctx_pflags2mta = (ctx->ctx_pflags2mta & ~SMFI_INTERNAL)
                              | internal_pflags;
        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[%ld]: wrong len %d >= %d",
                                g->a_ctx->ctx_smfi->xxfi_name,
                                (long) 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[%ld]: inet_aton failed",
                                        g->a_ctx->ctx_smfi->xxfi_name,
                                        (long) 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[%ld]: mi_inet_pton failed",
                                        g->a_ctx->ctx_smfi->xxfi_name,
                                        (long) 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[%ld]: path too long",
                                        g->a_ctx->ctx_smfi->xxfi_name,
                                        (long) g->a_ctx->ctx_id);
                                return _SMFIS_ABORT;
                        }
                        sockaddr.sunix.sun_family = AF_UNIX;
                }
                else
# endif /* NETUNIX */
                {
                        smi_log(SMI_LOG_ERR,
                                "%s: connect[%ld]: unknown family %d",
                                g->a_ctx->ctx_smfi->xxfi_name,
                                (long) 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;
}

/*
**  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 &&
            g->a_ctx->ctx_smfi->xxfi_version > 3 &&
            (fi_data = g->a_ctx->ctx_smfi->xxfi_data) != NULL)
                return (*fi_data)(g->a_ctx);
        return SMFIS_CONTINUE;
}

/*
**  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)
}

/*
**  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 *, const char *));

        if (g == NULL)
                return _SMFIS_ABORT;
        if (g->a_ctx->ctx_smfi != NULL &&
            g->a_ctx->ctx_smfi->xxfi_version > 2 &&
            (fi_unknown = g->a_ctx->ctx_smfi->xxfi_unknown) != NULL)
                return (*fi_unknown)(g->a_ctx, (const char *) g->a_buf);
        return SMFIS_CONTINUE;
}

/*
**  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_DATA:
                i = CI_DATA;
                break;
          case SMFIC_BODYEOB:
                i = CI_EOM;
                break;
          case SMFIC_EOH:
                i = CI_EOH;
                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;
{
        sfsistat (*fi_close) __P((SMFICTX *));

        if (g == NULL)
                return _SMFIS_ABORT;
        if (g->a_ctx->ctx_smfi != NULL &&
            (fi_close = g->a_ctx->ctx_smfi->xxfi_close) != NULL)
                (void) (*fi_close)(g->a_ctx);
        mi_clr_macros(g->a_ctx, 0);
        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;
        if (bitset(SMFIP_NODATA, fl))
                next_states[ST_DATA] |= NX_SKIP;
        if (bitset(SMFIP_NOUNKNOWN, fl))
                next_states[ST_UNKN] |= 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_aflags))
                return false;

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

#if _FFR_WORKERS_POOL
/*
**  MI_RD_SOCKET_READY - checks if the socket is ready for read(2)
**
**      Parameters:
**              sd -- socket_t
**
**      Returns:
**              true iff socket is ready for read(2)
*/

#define MI_RD_CMD_TO  1
#define MI_RD_MAX_ERR 16

static bool
mi_rd_socket_ready (sd)
        socket_t sd;
{
        int n;
        int nerr = 0;
#if SM_CONF_POLL
        struct pollfd pfd;
#else /* SM_CONF_POLL */
        fd_set  rd_set, exc_set;
#endif /* SM_CONF_POLL */

        do
        {
#if SM_CONF_POLL
                pfd.fd = sd;
                pfd.events = POLLIN;
                pfd.revents = 0;

                n = poll(&pfd, 1, MI_RD_CMD_TO);
#else /* SM_CONF_POLL */
                struct timeval timeout;

                FD_ZERO(&rd_set);
                FD_ZERO(&exc_set);
                FD_SET(sd, &rd_set);
                FD_SET(sd, &exc_set);

                timeout.tv_sec = MI_RD_CMD_TO / 1000;
                timeout.tv_usec = 0;
                n = select(sd + 1, &rd_set, NULL, &exc_set, &timeout);
#endif /* SM_CONF_POLL */

                if (n < 0)
                {
                        if (errno == EINTR)
                        {
                                nerr++;
                                continue;
                        }
                        return true;
                }

                if (n == 0)
                        return false;
                break;
        } while (nerr < MI_RD_MAX_ERR);
        if (nerr >= MI_RD_MAX_ERR)
                return false;

#if SM_CONF_POLL
        return (pfd.revents != 0);
#else /* SM_CONF_POLL */
        return FD_ISSET(sd, &rd_set) || FD_ISSET(sd, &exc_set);
#endif /* SM_CONF_POLL */
}
#endif /* _FFR_WORKERS_POOL */