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

   1 /* -*-c-*-
   2  *
   3  * $Id: identify.c,v 1.2 1999/07/03 13:56:59 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 1.2  1999/07/03 13:56:59  mdw
  33  * Log connections to syslog or stderr as appropriate.
  34  *
  35  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  36  * Initial revision.
  37  *
  38  */
  39
  40 /*----- Header files ------------------------------------------------------*/
  41
  42 #include "config.h"
  43
  44 #include <errno.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <time.h>
  49
  50 #include <sys/types.h>
  51 #include <sys/time.h>
  52 #include <unistd.h>
  53 #include <syslog.h>
  54
  55 #include <sys/socket.h>
  56 #include <netinet/in.h>
  57 #include <arpa/inet.h>
  58 #include <netdb.h>
  59
  60 #include <mLib/alloc.h>
  61 #include <mLib/conn.h>
  62 #include <mLib/dstr.h>
  63 #include <mLib/report.h>
  64 #include <mLib/sel.h>
  65 #include <mLib/selbuf.h>
  66 #include <mLib/str.h>
  67
  68 #include "bres.h"
  69 #include "fw.h"
  70 #include "ident.h"
  71 #include "identify.h"
  72
  73 /*----- Magic numbers -----------------------------------------------------*/
  74
  75 #define TIMEOUT 15                      /* Seconds to wait for answers */
  76
  77 /*----- Data structures ---------------------------------------------------*/
  78
  79 /* --- Structure to track the progress of an identification --- */
  80
  81 typedef struct id {
  82   id_req q;                             /* Copy of client's request block */
  83   void (*func)(void */*p*/);            /* Function to call when done */
  84   void *p;                              /* Argument to pass to function */
  85   time_t when;                          /* When the connection occurred */
  86   conn c;                               /* Connection selector */
  87   unsigned state;                       /* Current state of the world */
  88   bres_client r;                        /* Backgd resolver client block */
  89   char host[64];                        /* Resolved hostname */
  90   char user[32];                        /* Authenticated client user */
  91   sel_timer t;                          /* Timeout selector */
  92   selbuf id;                            /* Reader for the RFC931 client */
  93 } id;
  94
  95 #define S_HOST 1u                       /* Read the hostname from resolver */
  96 #define S_USER 2u                       /* Read the username from RFC931 */
  97 #define S_UCONN 4u                      /* Connected to remote RFC931 */
  98 #define S_TIMER 8u                      /* Timeout has completed */
  99
 100 /*----- Main code ---------------------------------------------------------*/
 101
 102 /* --- @id_done@ --- *
 103  *
 104  * Arguments:   @id *i@ = pointer to identification block
 105  *
 106  * Returns:     ---
 107  *
 108  * Use:         Finishes with an identification block.
 109  */
 110
 111 static void id_done(id *i)
 112 {
 113   char buf[64];
 114   struct tm *tm;
 115
 116   /* --- Close down the various dependent bits --- */
 117
 118   if (!(i->state & S_HOST))
 119     bres_abort(&i->r);
 120   if (!(i->state & S_UCONN))
 121     conn_kill(&i->c);
 122   else if (!(i->state & S_USER))
 123     selbuf_disable(&i->id);
 124   if (!(i->state & S_TIMER))
 125     sel_rmtimer(&i->t);
 126
 127   /* --- Report the final result --- */
 128
 129   tm = localtime(&i->when);
 130   strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm);
 131   if (flags & FW_SYSLOG) {
 132     syslog(LOG_NOTICE, "%s %s %s from %s@%s [%s]\n",
 133            buf, i->q.desc, i->q.act,
 134            i->user, i->host, inet_ntoa(i->q.rsin.sin_addr));
 135   } else {
 136     fprintf(stderr, "%s %s %s from %s@%s [%s]\n",
 137            buf, i->q.desc, i->q.act,
 138            i->user, i->host, inet_ntoa(i->q.rsin.sin_addr));
 139   }
 140
 141   /* --- Dispose of the block --- */
 142
 143   i->func(i->p);
 144   free(i);
 145 }
 146
 147 /* --- @id_res@ --- *
 148  *
 149  * Arguments:   @const char *host@ = name of the resolved host
 150  *              @void *vp@ = pointer to identification block
 151  *
 152  * Returns:     ---
 153  *
 154  * Use:         Responds to a completed reverse name resolution.
 155  */
 156
 157 static void id_res(const char *host, void *vp)
 158 {
 159   id *i = vp;
 160   str_sanitize(i->host, host, sizeof(i->host));
 161   i->state |= S_HOST;
 162   if (i->state & S_USER)
 163     id_done(i);
 164 }
 165
 166 /* --- @id_ident@ --- *
 167  *
 168  * Arguments:   @char *p@ = pointer to string read from server
 169  *              @void *vp@ = pointer to identification block
 170  *
 171  * Returns:     ---
 172  *
 173  * Use:         Responds to a line read from the remote RFC931 server.
 174  */
 175
 176 static void id_ident(char *p, void *vp)
 177 {
 178   id *i = vp;
 179
 180   /* --- Get rid of the connection --- */
 181
 182   i->state |= S_USER;
 183   selbuf_disable(&i->id);
 184   close(i->id.reader.fd);
 185
 186   /* --- Read the information from the returned line --- */
 187
 188   if (p) {
 189     ident idbuf;
 190     ident_parse(p, &idbuf);
 191     if (idbuf.type == ident_userid)
 192       str_sanitize(i->user, idbuf.u.userid.user, sizeof(i->user));
 193   }
 194
 195   /* --- Maybe finish off this identification --- */
 196
 197   if (i->state & S_HOST)
 198     id_done(i);
 199 }
 200
 201 /* --- @id_conn@ --- *
 202  *
 203  * Arguments:   @int fd@ = file descriptor connected
 204  *              @void *vp@ = pointer to identification block
 205  *
 206  * Returns:     ---
 207  *
 208  * Use:         Responds to a completed connection to the remote RFC931
 209  *              server.
 210  */
 211
 212 static void id_conn(int fd, void *vp)
 213 {
 214   id *i = vp;
 215
 216   if (fd == -1) {
 217     i->state |= S_USER | S_UCONN;
 218     if (i->state & S_HOST)
 219       id_done(i);
 220   } else {
 221     dstr d = DSTR_INIT;
 222     dstr_putf(&d, "%u, %u\n",
 223               ntohs(i->q.rsin.sin_port), ntohs(i->q.lsin.sin_port));
 224     write(fd, d.buf, d.len);
 225     dstr_destroy(&d);
 226     i->state |= S_UCONN;
 227     selbuf_init(&i->id, sel, fd, id_ident, i);
 228   }
 229 }
 230
 231 /* --- @id_timer@ --- *
 232  *
 233  * Arguments:   @struct timeval *tv@ = pointer to the current time
 234  *              @void *vp@ = pointer to identification block
 235  *
 236  * Returns:     ---
 237  *
 238  * Use:         Times an identification job out.
 239  */
 240
 241 static void id_timer(struct timeval *tv, void *vp)
 242 {
 243   id *i = vp;
 244   id_done(i);
 245 }
 246
 247 /* --- @identify@ --- *
 248  *
 249  * Arguments:   @const id_req *q@ = pointer to request block
 250  *              @void (*func)(void *p)@ = function to call when done
 251  *              @void *p@ = argument to pass to function
 252  *
 253  * Returns:     ---
 254  *
 255  * Use:         Starts a background ident lookup and reverse-resolve job
 256  *              which will, eventually, report a message to the system log.
 257  */
 258
 259 void identify(const id_req *q,
 260               void (*func)(void */*p*/), void *p)
 261 {
 262   id *i;
 263
 264   /* --- Initialize the block with stuff --- */
 265
 266   i = xmalloc(sizeof(*i));
 267   i->q = *q;
 268   i->func = func;
 269   i->p = p;
 270
 271   str_sanitize(i->host, inet_ntoa(q->rsin.sin_addr), sizeof(i->host));
 272   strcpy(i->user, "<ANONYMOUS>");
 273   i->state = 0;
 274   i->when = time(0);
 275
 276   /* --- Set up the connection to the identity server --- */
 277
 278   {
 279     int fd;
 280     struct sockaddr_in sin;
 281
 282     if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
 283       id_conn(-1, i);
 284     else {
 285       sin.sin_family = AF_INET;
 286       sin.sin_addr = q->lsin.sin_addr;
 287       sin.sin_port = 0;
 288       if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) {
 289         close(fd);
 290         id_conn(-1, i);
 291       } else {
 292         sin.sin_family = AF_INET;
 293         sin.sin_addr = q->rsin.sin_addr;
 294         sin.sin_port = htons(113);
 295         conn_init(&i->c, sel, fd,
 296                   (struct sockaddr *)&sin, sizeof(sin),
 297                   id_conn, i);
 298       }
 299     }
 300   }
 301
 302   /* --- Set up the name resolver --- */
 303
 304   bres_resolve(&i->r, q->rsin.sin_addr, id_res, i);
 305
 306   /* --- Set up the time limiter --- */
 307
 308   {
 309     struct timeval tv;
 310     gettimeofday(&tv, 0);
 311     tv.tv_sec += TIMEOUT;
 312     sel_addtimer(sel, &i->t, &tv, id_timer, i);
 313   }
 314 }
 315
 316 /*----- That's all, folks -------------------------------------------------*/