mdw@git.distorted.org.uk Git - fwd/blob - identify.c

   1 /* -*-c-*-
   2  *
   3  * $Id: identify.c,v 1.1 1999/07/01 08:56:23 mdw Exp $
   4  *
   5  * Identifies and logs the client of a connection
   6  *
   7  * (c) 1999 Mark Wooding
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: identify.c,v $
  32  * Revision 1.1  1999/07/01 08:56:23  mdw
  33  * Initial revision
  34  *
  35  */
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include "config.h"
  40
  41 #include <errno.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <time.h>
  46
  47 #include <sys/types.h>
  48 #include <sys/time.h>
  49 #include <unistd.h>
  50 #include <syslog.h>
  51
  52 #include <sys/socket.h>
  53 #include <netinet/in.h>
  54 #include <arpa/inet.h>
  55 #include <netdb.h>
  56
  57 #include <mLib/alloc.h>
  58 #include <mLib/conn.h>
  59 #include <mLib/dstr.h>
  60 #include <mLib/report.h>
  61 #include <mLib/sel.h>
  62 #include <mLib/selbuf.h>
  63 #include <mLib/str.h>
  64
  65 #include "bres.h"
  66 #include "fw.h"
  67 #include "ident.h"
  68 #include "identify.h"
  69
  70 /*----- Magic numbers -----------------------------------------------------*/
  71
  72 #define TIMEOUT 15                      /* Seconds to wait for answers */
  73
  74 /*----- Data structures ---------------------------------------------------*/
  75
  76 /* --- Structure to track the progress of an identification --- */
  77
  78 typedef struct id {
  79   id_req q;                             /* Copy of client's request block */
  80   void (*func)(void */*p*/);            /* Function to call when done */
  81   void *p;                              /* Argument to pass to function */
  82   time_t when;                          /* When the connection occurred */
  83   conn c;                               /* Connection selector */
  84   unsigned state;                       /* Current state of the world */
  85   bres_client r;                        /* Backgd resolver client block */
  86   char host[64];                        /* Resolved hostname */
  87   char user[32];                        /* Authenticated client user */
  88   sel_timer t;                          /* Timeout selector */
  89   selbuf id;                            /* Reader for the RFC931 client */
  90 } id;
  91
  92 #define S_HOST 1u                       /* Read the hostname from resolver */
  93 #define S_USER 2u                       /* Read the username from RFC931 */
  94 #define S_UCONN 4u                      /* Connected to remote RFC931 */
  95 #define S_TIMER 8u                      /* Timeout has completed */
  96
  97 /*----- Main code ---------------------------------------------------------*/
  98
  99 /* --- @id_done@ --- *
 100  *
 101  * Arguments:   @id *i@ = pointer to identification block
 102  *
 103  * Returns:     ---
 104  *
 105  * Use:         Finishes with an identification block.
 106  */
 107
 108 static void id_done(id *i)
 109 {
 110   char buf[64];
 111   struct tm *tm;
 112
 113   /* --- Close down the various dependent bits --- */
 114
 115   if (!(i->state & S_HOST))
 116     bres_abort(&i->r);
 117   if (!(i->state & S_UCONN))
 118     conn_kill(&i->c);
 119   else if (!(i->state & S_USER))
 120     selbuf_disable(&i->id);
 121   if (!(i->state & S_TIMER))
 122     sel_rmtimer(&i->t);
 123
 124   /* --- Report the final result --- */
 125
 126   tm = localtime(&i->when);
 127   strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm);
 128   syslog(LOG_NOTICE, "%s %s %s from %s@%s\n",
 129          buf, i->q.desc, i->q.act, i->user, i->host);
 130
 131   /* --- Dispose of the block --- */
 132
 133   i->func(i->p);
 134   free(i);
 135 }
 136
 137 /* --- @id_res@ --- *
 138  *
 139  * Arguments:   @const char *host@ = name of the resolved host
 140  *              @void *vp@ = pointer to identification block
 141  *
 142  * Returns:     ---
 143  *
 144  * Use:         Responds to a completed reverse name resolution.
 145  */
 146
 147 static void id_res(const char *host, void *vp)
 148 {
 149   id *i = vp;
 150   str_sanitize(i->host, host, sizeof(i->host));
 151   i->state |= S_HOST;
 152   if (i->state & S_USER)
 153     id_done(i);
 154 }
 155
 156 /* --- @id_ident@ --- *
 157  *
 158  * Arguments:   @char *p@ = pointer to string read from server
 159  *              @void *vp@ = pointer to identification block
 160  *
 161  * Returns:     ---
 162  *
 163  * Use:         Responds to a line read from the remote RFC931 server.
 164  */
 165
 166 static void id_ident(char *p, void *vp)
 167 {
 168   id *i = vp;
 169
 170   /* --- Get rid of the connection --- */
 171
 172   i->state |= S_USER;
 173   selbuf_disable(&i->id);
 174   close(i->id.reader.fd);
 175
 176   /* --- Read the information from the returned line --- */
 177
 178   if (p) {
 179     ident idbuf;
 180     ident_parse(p, &idbuf);
 181     if (idbuf.type == ident_userid)
 182       str_sanitize(i->user, idbuf.u.userid.user, sizeof(i->user));
 183   }
 184
 185   /* --- Maybe finish off this identification --- */
 186
 187   if (i->state & S_HOST)
 188     id_done(i);
 189 }
 190
 191 /* --- @id_conn@ --- *
 192  *
 193  * Arguments:   @int fd@ = file descriptor connected
 194  *              @void *vp@ = pointer to identification block
 195  *
 196  * Returns:     ---
 197  *
 198  * Use:         Responds to a completed connection to the remote RFC931
 199  *              server.
 200  */
 201
 202 static void id_conn(int fd, void *vp)
 203 {
 204   id *i = vp;
 205
 206   if (fd == -1) {
 207     i->state |= S_USER | S_UCONN;
 208     if (i->state & S_HOST)
 209       id_done(i);
 210   } else {
 211     dstr d = DSTR_INIT;
 212     dstr_putf(&d, "%u, %u\n",
 213               ntohs(i->q.rsin.sin_port), ntohs(i->q.lsin.sin_port));
 214     write(fd, d.buf, d.len);
 215     dstr_destroy(&d);
 216     i->state |= S_UCONN;
 217     selbuf_init(&i->id, sel, fd, id_ident, i);
 218   }
 219 }
 220
 221 /* --- @id_timer@ --- *
 222  *
 223  * Arguments:   @struct timeval *tv@ = pointer to the current time
 224  *              @void *vp@ = pointer to identification block
 225  *
 226  * Returns:     ---
 227  *
 228  * Use:         Times an identification job out.
 229  */
 230
 231 static void id_timer(struct timeval *tv, void *vp)
 232 {
 233   id *i = vp;
 234   id_done(i);
 235 }
 236
 237 /* --- @identify@ --- *
 238  *
 239  * Arguments:   @const id_req *q@ = pointer to request block
 240  *              @void (*func)(void *p)@ = function to call when done
 241  *              @void *p@ = argument to pass to function
 242  *
 243  * Returns:     ---
 244  *
 245  * Use:         Starts a background ident lookup and reverse-resolve job
 246  *              which will, eventually, report a message to the system log.
 247  */
 248
 249 void identify(const id_req *q,
 250               void (*func)(void */*p*/), void *p)
 251 {
 252   id *i;
 253
 254   /* --- Initialize the block with stuff --- */
 255
 256   i = xmalloc(sizeof(*i));
 257   i->q = *q;
 258   i->func = func;
 259   i->p = p;
 260
 261   str_sanitize(i->host, inet_ntoa(q->rsin.sin_addr), sizeof(i->host));
 262   strcpy(i->user, "<ANONYMOUS>");
 263   i->state = 0;
 264   i->when = time(0);
 265
 266   /* --- Set up the connection to the identity server --- */
 267
 268   {
 269     int fd;
 270     struct sockaddr_in sin;
 271
 272     if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
 273       id_conn(-1, i);
 274     else {
 275       sin.sin_family = AF_INET;
 276       sin.sin_addr = q->lsin.sin_addr;
 277       sin.sin_port = 0;
 278       if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) {
 279         close(fd);
 280         id_conn(-1, i);
 281       } else {
 282         sin.sin_family = AF_INET;
 283         sin.sin_addr = q->rsin.sin_addr;
 284         sin.sin_port = htons(113);
 285         conn_init(&i->c, sel, fd,
 286                   (struct sockaddr *)&sin, sizeof(sin),
 287                   id_conn, i);
 288       }
 289     }
 290   }
 291
 292   /* --- Set up the name resolver --- */
 293
 294   bres_resolve(&i->r, q->rsin.sin_addr, id_res, i);
 295
 296   /* --- Set up the time limiter --- */
 297
 298   {
 299     struct timeval tv;
 300     gettimeofday(&tv, 0);
 301     tv.tv_sec += TIMEOUT;
 302     sel_addtimer(sel, &i->t, &tv, id_timer, i);
 303   }
 304 }
 305
 306 /*----- That's all, folks -------------------------------------------------*/