postscreen_state.c

[詳解]

/*++
/* NAME
/*  postscreen_state 3
/* SUMMARY
/*  postscreen session state and queue length management
/* SYNOPSIS
/*  #include <postscreen.h>
/*
/*  PSC_STATE *psc_new_session_state(stream, client_addr, client_port,
/*                      server_addr, server_port)
/*  VSTREAM *stream;
/*  const char *client_addr;
/*  const char *client_port;
/*  const char *server_addr;
/*  const char *server_port;
/*
/*  void    psc_free_session_state(state)
/*  PSC_STATE *state;
/*
/*  char    *psc_print_state_flags(flags, context)
/*  int flags;
/*  const char *context;
/*
/*  void    PSC_ADD_SERVER_STATE(state, server_fd)
/*  PSC_STATE *state;
/*  int server_fd;
/*
/*  void    PSC_DEL_CLIENT_STATE(state)
/*  PSC_STATE *state;
/*
/*  void    PSC_DROP_SESSION_STATE(state, final_reply)
/*  PSC_STATE *state;
/*  const char *final_reply;
/*
/*  void    PSC_ENFORCE_SESSION_STATE(state, rcpt_reply)
/*  PSC_STATE *state;
/*  const char *rcpt_reply;
/*
/*  void    PSC_PASS_SESSION_STATE(state, testname, pass_flag)
/*  PSC_STATE *state;
/*  const char *testname;
/*  int pass_flag;
/*
/*  void    PSC_FAIL_SESSION_STATE(state, fail_flag)
/*  PSC_STATE *state;
/*  int fail_flag;
/*
/*  void    PSC_UNFAIL_SESSION_STATE(state, fail_flag)
/*  PSC_STATE *state;
/*  int fail_flag;
/* DESCRIPTION
/*  This module maintains per-client session state, and two
/*  global file descriptor counters:
/* .IP psc_check_queue_length
/*  The total number of remote SMTP client sockets.
/* .IP psc_post_queue_length
/*  The total number of server file descriptors that are currently
/*  in use for client file descriptor passing. This number
/*  equals the number of client file descriptors in transit.
/* .PP
/*  psc_new_session_state() creates a new session state object
/*  for the specified client stream, and increments the
/*  psc_check_queue_length counter.  The flags and per-test time
/*  stamps are initialized with PSC_INIT_TESTS(), or for concurrent
/*  sessions, with PSC_INIT_TEST_FLAGS_ONLY().  The addr and
/*  port arguments are null-terminated strings with the remote
/*  SMTP client endpoint. The _reply members are set to
/*  polite "try again" SMTP replies. The protocol member is set
/*  to "SMTP".
/*
/*  The psc_stress variable is set to non-zero when
/*  psc_check_queue_length passes over a high-water mark.
/*
/*  psc_free_session_state() destroys the specified session state
/*  object, closes the applicable I/O channels, and decrements
/*  the applicable file descriptor counters: psc_check_queue_length
/*  and psc_post_queue_length.
/*
/*  The psc_stress variable is reset to zero when psc_check_queue_length
/*  passes under a low-water mark.
/*
/*  psc_print_state_flags() converts per-session flags into
/*  human-readable form. The context is for error reporting.
/*  The result is overwritten upon each call.
/*
/*  PSC_ADD_SERVER_STATE() updates the specified session state
/*  object with the specified server file descriptor, and
/*  increments the global psc_post_queue_length file descriptor
/*  counter.
/*
/*  PSC_DEL_CLIENT_STATE() updates the specified session state
/*  object, closes the client stream, and decrements the global
/*  psc_check_queue_length file descriptor counter.
/*
/*  PSC_DROP_SESSION_STATE() updates the specified session state
/*  object and closes the client stream after sending the
/*  specified SMTP reply.
/*
/*  PSC_ENFORCE_SESSION_STATE() updates the specified session
/*  state object. It arranges that the built-in SMTP engine
/*  logs sender/recipient information and rejects all RCPT TO
/*  commands with the specified SMTP reply.
/*
/*  PSC_PASS_SESSION_STATE() sets the specified "pass" flag.
/*  The testname is used for debug logging.
/*
/*  PSC_FAIL_SESSION_STATE() sets the specified "fail" flag.
/*
/*  PSC_UNFAIL_SESSION_STATE() unsets the specified "fail" flag.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*
/*  Wietse Venema
/*  Google, Inc.
/*  111 8th Avenue
/*  New York, NY 10011, USA
/*--*/

/* System library. */

#include <sys_defs.h>

/* Utility library. */

#include <msg.h>
#include <mymalloc.h>
#include <name_mask.h>
#include <htable.h>

/* Global library. */

#include <mail_proto.h>

/* Master server protocols. */

#include <mail_server.h>

/* Application-specific. */

#include <postscreen.h>

/* psc_new_session_state - fill in connection state for event processing */

PSC_STATE *psc_new_session_state(VSTREAM *stream,
                         const char *client_addr,
                         const char *client_port,
                         const char *server_addr,
                         const char *server_port)
{
    PSC_STATE *state;

    state = (PSC_STATE *) mymalloc(sizeof(*state));
    if ((state->smtp_client_stream = stream) != 0)
    psc_check_queue_length++;
    state->smtp_server_fd = (-1);
    state->smtp_client_addr = mystrdup(client_addr);
    state->smtp_client_port = mystrdup(client_port);
    state->smtp_server_addr = mystrdup(server_addr);
    state->smtp_server_port = mystrdup(server_port);
    state->send_buf = vstring_alloc(100);
    state->test_name = "TEST NAME HERE";
    state->dnsbl_reply = 0;
    state->final_reply = "421 4.3.2 Service currently unavailable\r\n";
    state->rcpt_reply = "450 4.3.2 Service currently unavailable\r\n";
    state->command_count = 0;
    state->protocol = MAIL_PROTO_SMTP;
    state->helo_name = 0;
    state->sender = 0;
    state->cmd_buffer = 0;
    state->read_state = 0;
    state->ehlo_discard_mask = 0;       /* XXX Should be ~0 */
    state->expand_buf = 0;
    state->where = PSC_SMTPD_CMD_CONNECT;

    /*
     * Update the stress level.
     */
    if (psc_stress == 0
    && psc_check_queue_length >= psc_hiwat_check_queue_length) {
    psc_stress = 1;
    msg_info("entering STRESS mode with %d connections",
         psc_check_queue_length);
    }

    /*
     * Update the per-client session count.
     */
    if ((state->client_info = (PSC_CLIENT_INFO *)
     htable_find(psc_client_concurrency, client_addr)) == 0) {
    state->client_info = (PSC_CLIENT_INFO *)
        mymalloc(sizeof(state->client_info[0]));
    (void) htable_enter(psc_client_concurrency, client_addr,
                (void *) state->client_info);
    PSC_INIT_TESTS(state);
    state->client_info->concurrency = 1;
    state->client_info->pass_new_count = 0;
    } else {
    PSC_INIT_TEST_FLAGS_ONLY(state);
    state->client_info->concurrency += 1;
    }

    return (state);
}

/* psc_free_session_state - destroy connection state including connections */

void    psc_free_session_state(PSC_STATE *state)
{
    const char *myname = "psc_free_session_state";
    HTABLE_INFO *ht;

    /*
     * Update the per-client session count.
     */
    if ((ht = htable_locate(psc_client_concurrency,
                state->smtp_client_addr)) == 0)
    msg_panic("%s: unknown client address: %s",
          myname, state->smtp_client_addr);
    if (--(state->client_info->concurrency) == 0)
    htable_delete(psc_client_concurrency, state->smtp_client_addr, myfree);

    if (state->smtp_client_stream != 0) {
    event_server_disconnect(state->smtp_client_stream);
    psc_check_queue_length--;
    }
    if (state->smtp_server_fd >= 0) {
    close(state->smtp_server_fd);
    psc_post_queue_length--;
    }
    if (state->send_buf != 0)
    state->send_buf = vstring_free(state->send_buf);
    myfree(state->smtp_client_addr);
    myfree(state->smtp_client_port);
    myfree(state->smtp_server_addr);
    myfree(state->smtp_server_port);
    if (state->dnsbl_reply)
    vstring_free(state->dnsbl_reply);
    if (state->helo_name)
    myfree(state->helo_name);
    if (state->sender)
    myfree(state->sender);
    if (state->cmd_buffer)
    vstring_free(state->cmd_buffer);
    if (state->expand_buf)
    vstring_free(state->expand_buf);
    myfree((void *) state);

    if (psc_check_queue_length < 0 || psc_post_queue_length < 0)
    msg_panic("bad queue length: check_queue=%d, post_queue=%d",
          psc_check_queue_length, psc_post_queue_length);

    /*
     * Update the stress level.
     */
    if (psc_stress != 0
    && psc_check_queue_length <= psc_lowat_check_queue_length) {
    psc_stress = 0;
    msg_info("leaving STRESS mode with %d connections",
         psc_check_queue_length);
    }
}

/* psc_print_state_flags - format state flags */

const char *psc_print_state_flags(int flags, const char *context)
{
    static const NAME_MASK flags_mask[] = {
    "NOFORWARD", PSC_STATE_FLAG_NOFORWARD,
    "USING_TLS", PSC_STATE_FLAG_USING_TLS,
    "NEW", PSC_STATE_FLAG_NEW,
    "BLIST_FAIL", PSC_STATE_FLAG_BLIST_FAIL,
    "HANGUP", PSC_STATE_FLAG_HANGUP,
    /* unused */
    "WLIST_FAIL", PSC_STATE_FLAG_WLIST_FAIL,

    "PREGR_FAIL", PSC_STATE_FLAG_PREGR_FAIL,
    "PREGR_PASS", PSC_STATE_FLAG_PREGR_PASS,
    "PREGR_TODO", PSC_STATE_FLAG_PREGR_TODO,
    "PREGR_DONE", PSC_STATE_FLAG_PREGR_DONE,

    "DNSBL_FAIL", PSC_STATE_FLAG_DNSBL_FAIL,
    "DNSBL_PASS", PSC_STATE_FLAG_DNSBL_PASS,
    "DNSBL_TODO", PSC_STATE_FLAG_DNSBL_TODO,
    "DNSBL_DONE", PSC_STATE_FLAG_DNSBL_DONE,

    "PIPEL_FAIL", PSC_STATE_FLAG_PIPEL_FAIL,
    "PIPEL_PASS", PSC_STATE_FLAG_PIPEL_PASS,
    "PIPEL_TODO", PSC_STATE_FLAG_PIPEL_TODO,
    "PIPEL_SKIP", PSC_STATE_FLAG_PIPEL_SKIP,

    "NSMTP_FAIL", PSC_STATE_FLAG_NSMTP_FAIL,
    "NSMTP_PASS", PSC_STATE_FLAG_NSMTP_PASS,
    "NSMTP_TODO", PSC_STATE_FLAG_NSMTP_TODO,
    "NSMTP_SKIP", PSC_STATE_FLAG_NSMTP_SKIP,

    "BARLF_FAIL", PSC_STATE_FLAG_BARLF_FAIL,
    "BARLF_PASS", PSC_STATE_FLAG_BARLF_PASS,
    "BARLF_TODO", PSC_STATE_FLAG_BARLF_TODO,
    "BARLF_SKIP", PSC_STATE_FLAG_BARLF_SKIP,
    0,
    };

    return (str_name_mask_opt((VSTRING *) 0, context, flags_mask, flags,
                  NAME_MASK_PIPE | NAME_MASK_NUMBER));
}