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

   1 /* -*-c-*-
   2  *
   3  * $Id: identify.c,v 1.4 1999/07/27 18:30:53 mdw Exp $
   4  *
   5  * Identifies and logs the client of a connection
   6  *
   7  * (c) 1999 Straylight/Edgeware
   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 1.4  1999/07/27 18:30:53  mdw
  33  * Various minor portability fixes.
  34  *
  35  * Revision 1.3  1999/07/26 23:26:21  mdw
  36  * Minor modifications for new design.
  37  *
  38  * Revision 1.2  1999/07/03 13:56:59  mdw
  39  * Log connections to syslog or stderr as appropriate.
  40  *
  41  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  42  * Initial revision.
  43  *
  44  */
  45
  46 /*----- Header files ------------------------------------------------------*/
  47
  48 #include "config.h"
  49
  50 #include <errno.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <time.h>
  55
  56 #include <sys/types.h>
  57 #include <sys/time.h>
  58 #include <unistd.h>
  59 #include <syslog.h>
  60
  61 #include <sys/socket.h>
  62 #include <netinet/in.h>
  63 #include <arpa/inet.h>
  64 #include <netdb.h>
  65
  66 #include <mLib/alloc.h>
  67 #include <mLib/conn.h>
  68 #include <mLib/dstr.h>
  69 #include <mLib/report.h>
  70 #include <mLib/sel.h>
  71 #include <mLib/selbuf.h>
  72 #include <mLib/str.h>
  73
  74 #include "bres.h"
  75 #include "fw.h"
  76 #include "ident.h"
  77 #include "identify.h"
  78
  79 /*----- Magic numbers -----------------------------------------------------*/
  80
  81 #define TIMEOUT 15                      /* Seconds to wait for answers */
  82
  83 /*----- Data structures ---------------------------------------------------*/
  84
  85 /* --- Structure to track the progress of an identification --- */
  86
  87 typedef struct id {
  88   id_req q;                             /* Copy of client's request block */
  89   time_t when;                          /* When the connection occurred */
  90   conn c;                               /* Connection selector */
  91   unsigned state;                       /* Current state of the world */
  92   bres_client r;                        /* Backgd resolver client block */
  93   char host[64];                        /* Resolved hostname */
  94   char user[32];                        /* Authenticated client user */
  95   sel_timer t;                          /* Timeout selector */
  96   selbuf id;                            /* Reader for the RFC931 client */
  97 } id;
  98
  99 #define S_HOST 1u                       /* Read the hostname from resolver */
 100 #define S_USER 2u                       /* Read the username from RFC931 */
 101 #define S_UCONN 4u                      /* Connected to remote RFC931 */
 102 #define S_TIMER 8u                      /* Timeout has completed */
 103
 104 /*----- Main code ---------------------------------------------------------*/
 105
 106 /* --- @id_done@ --- *
 107  *
 108  * Arguments:   @id *i@ = pointer to identification block
 109  *
 110  * Returns:     ---
 111  *
 112  * Use:         Finishes with an identification block.
 113  */
 114
 115 static void id_done(id *i)
 116 {
 117   /* --- Close down the various dependent bits --- */
 118
 119   if (!(i->state & S_HOST))
 120     bres_abort(&i->r);
 121   if (!(i->state & S_UCONN))
 122     conn_kill(&i->c);
 123   else if (!(i->state & S_USER))
 124     selbuf_disable(&i->id);
 125   if (!(i->state & S_TIMER))
 126     sel_rmtimer(&i->t);
 127
 128   /* --- Report the final result --- */
 129
 130   fw_log(i->when, "[%s] %s from %s@%s [%s]",
 131          i->q.desc, i->q.act,
 132          i->user, i->host, inet_ntoa(i->q.rsin.sin_addr));
 133
 134   /* --- Dispose of the block --- */
 135
 136   REFFD_DEC(i->q.r);
 137   free(i);
 138 }
 139
 140 /* --- @id_res@ --- *
 141  *
 142  * Arguments:   @const char *host@ = name of the resolved host
 143  *              @void *vp@ = pointer to identification block
 144  *
 145  * Returns:     ---
 146  *
 147  * Use:         Responds to a completed reverse name resolution.
 148  */
 149
 150 static void id_res(const char *host, void *vp)
 151 {
 152   id *i = vp;
 153   str_sanitize(i->host, host, sizeof(i->host));
 154   i->state |= S_HOST;
 155   if (i->state & S_USER)
 156     id_done(i);
 157 }
 158
 159 /* --- @id_ident@ --- *
 160  *
 161  * Arguments:   @char *p@ = pointer to string read from server
 162  *              @void *vp@ = pointer to identification block
 163  *
 164  * Returns:     ---
 165  *
 166  * Use:         Responds to a line read from the remote RFC931 server.
 167  */
 168
 169 static void id_ident(char *p, void *vp)
 170 {
 171   id *i = vp;
 172
 173   /* --- Get rid of the connection --- */
 174
 175   i->state |= S_USER;
 176   selbuf_disable(&i->id);
 177   close(i->id.reader.fd);
 178
 179   /* --- Read the information from the returned line --- */
 180
 181   if (p) {
 182     ident idbuf;
 183     ident_parse(p, &idbuf);
 184     if (idbuf.type == ident_userid)
 185       str_sanitize(i->user, idbuf.u.userid.user, sizeof(i->user));
 186   }
 187
 188   /* --- Maybe finish off this identification --- */
 189
 190   if (i->state & S_HOST)
 191     id_done(i);
 192 }
 193
 194 /* --- @id_conn@ --- *
 195  *
 196  * Arguments:   @int fd@ = file descriptor connected
 197  *              @void *vp@ = pointer to identification block
 198  *
 199  * Returns:     ---
 200  *
 201  * Use:         Responds to a completed connection to the remote RFC931
 202  *              server.
 203  */
 204
 205 static void id_conn(int fd, void *vp)
 206 {
 207   id *i = vp;
 208
 209   if (fd == -1) {
 210     i->state |= S_USER | S_UCONN;
 211     if (i->state & S_HOST)
 212       id_done(i);
 213   } else {
 214     dstr d = DSTR_INIT;
 215     dstr_putf(&d, "%u, %u\n",
 216               ntohs(i->q.rsin.sin_port), ntohs(i->q.lsin.sin_port));
 217     write(fd, d.buf, d.len);
 218     dstr_destroy(&d);
 219     i->state |= S_UCONN;
 220     selbuf_init(&i->id, sel, fd, id_ident, i);
 221   }
 222 }
 223
 224 /* --- @id_timer@ --- *
 225  *
 226  * Arguments:   @struct timeval *tv@ = pointer to the current time
 227  *              @void *vp@ = pointer to identification block
 228  *
 229  * Returns:     ---
 230  *
 231  * Use:         Times an identification job out.
 232  */
 233
 234 static void id_timer(struct timeval *tv, void *vp)
 235 {
 236   id *i = vp;
 237   id_done(i);
 238 }
 239
 240 /* --- @identify@ --- *
 241  *
 242  * Arguments:   @const id_req *q@ = pointer to request block
 243  *
 244  * Returns:     ---
 245  *
 246  * Use:         Starts a background ident lookup and reverse-resolve job
 247  *              which will, eventually, report a message to the system log.
 248  */
 249
 250 void identify(const id_req *q)
 251 {
 252   id *i;
 253
 254   /* --- Initialize the block with stuff --- */
 255
 256   i = xmalloc(sizeof(*i));
 257   i->q = *q;
 258   REFFD_INC(i->q.r);
 259
 260   str_sanitize(i->host, inet_ntoa(q->rsin.sin_addr), sizeof(i->host));
 261   strcpy(i->user, "<ANONYMOUS>");
 262   i->state = 0;
 263   i->when = time(0);
 264
 265   /* --- Set up the connection to the identity server --- */
 266
 267   {
 268     int fd;
 269     struct sockaddr_in sin;
 270
 271     if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0)
 272       id_conn(-1, i);
 273     else {
 274       memset(&sin, 0, sizeof(sin));
 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         int opt = 1;
 283         sin.sin_family = AF_INET;
 284         sin.sin_addr = q->rsin.sin_addr;
 285         sin.sin_port = htons(113);
 286         setsockopt(fd, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 287         conn_init(&i->c, sel, fd,
 288                   (struct sockaddr *)&sin, sizeof(sin),
 289                   id_conn, i);
 290       }
 291     }
 292   }
 293
 294   /* --- Set up the name resolver --- */
 295
 296   bres_resolve(&i->r, q->rsin.sin_addr, id_res, i);
 297
 298   /* --- Set up the time limiter --- */
 299
 300   {
 301     struct timeval tv;
 302     gettimeofday(&tv, 0);
 303     tv.tv_sec += TIMEOUT;
 304     sel_addtimer(sel, &i->t, &tv, id_timer, i);
 305   }
 306 }
 307
 308 /*----- That's all, folks -------------------------------------------------*/