ircd/m_cap.c

   1 /*
   2  * IRC - Internet Relay Chat, ircd/m_cap.c
   3  * Copyright (C) 2004 Kevin L. Mitchell <klmitch@mit.edu>
   4  *
   5  * See file AUTHORS in IRC package for additional names of
   6  * the programmers.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 1, or (at your option)
  11  * any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22 /** @file
  23  * @brief Capability negotiation commands
  24  * @version $Id: m_cap.c,v 1.2 2005/04/05 01:46:05 entrope Exp $
  25  */
  26
  27 #include "config.h"
  28
  29 #include "client.h"
  30 #include "ircd.h"
  31 #include "ircd_chattr.h"
  32 #include "ircd_log.h"
  33 #include "ircd_reply.h"
  34 #include "ircd_snprintf.h"
  35 #include "ircd_string.h"
  36 #include "msg.h"
  37 #include "numeric.h"
  38 #include "send.h"
  39 #include "s_user.h"
  40
  41 #include <stdlib.h>
  42 #include <string.h>
  43
  44 typedef int (*bqcmp)(const void *, const void *);
  45
  46 static struct capabilities {
  47   enum Capab cap;
  48   char *capstr;
  49   unsigned long flags;
  50   char *name;
  51   int namelen;
  52 } capab_list[] = {
  53 #define _CAP(cap, flags, name)                                                \
  54         { CAP_ ## cap, #cap, (flags), (name), sizeof(name) - 1 }
  55   CAPLIST
  56 #undef _CAP
  57 };
  58
  59 #define CAPAB_LIST_LEN  (sizeof(capab_list) / sizeof(struct capabilities))
  60
  61 static int
  62 capab_sort(const struct capabilities *cap1, const struct capabilities *cap2)
  63 {
  64   return ircd_strcmp(cap1->name, cap2->name);
  65 }
  66
  67 static int
  68 capab_search(const char *key, const struct capabilities *cap)
  69 {
  70   const char *rb = cap->name;
  71   while (ToLower(*key) == ToLower(*rb)) /* walk equivalent part of strings */
  72     if (!*key++) /* hit the end, all right... */
  73       return 0;
  74     else /* OK, let's move on... */
  75       rb++;
  76
  77   /* If the character they differ on happens to be a space, and it happens
  78    * to be the same length as the capability name, then we've found a
  79    * match; otherwise, return the difference of the two.
  80    */
  81   return (IsSpace(*key) && !*rb) ? 0 : (ToLower(*key) - ToLower(*rb));
  82 }
  83
  84 static struct capabilities *
  85 find_cap(const char **caplist_p, int *neg_p)
  86 {
  87   static int inited = 0;
  88   const char *caplist = *caplist_p;
  89   struct capabilities *cap = 0;
  90
  91   *neg_p = 0; /* clear negative flag... */
  92
  93   if (!inited) { /* First, let's sort the array... */
  94     qsort(capab_list, CAPAB_LIST_LEN, sizeof(struct capabilities),
  95           (bqcmp)capab_sort);
  96     inited++; /* remember that we've done this step... */
  97   }
  98
  99   /* Next, find first non-whitespace character... */
 100   while (*caplist && IsSpace(*caplist))
 101     caplist++;
 102
 103   /* We are now at the beginning of an element of the list; is it negative? */
 104   if (*caplist == '-') {
 105     caplist++; /* yes; step past the flag... */
 106     *neg_p = 1; /* remember that it is negative... */
 107   }
 108
 109   /* OK, now see if we can look up the capability... */
 110   if (*caplist) {
 111     if (!(cap = (struct capabilities *)bsearch(caplist, capab_list,
 112                                                CAPAB_LIST_LEN,
 113                                                sizeof(struct capabilities),
 114                                                (bqcmp)capab_search))) {
 115       /* Couldn't find the capability; advance to first whitespace character */
 116       while (*caplist && !IsSpace(*caplist))
 117         caplist++;
 118     } else
 119       caplist += cap->namelen; /* advance to end of capability name */
 120   }
 121
 122   assert(caplist != *caplist_p || !*caplist); /* we *must* advance */
 123
 124   /* move ahead in capability list string--or zero pointer if we hit end */
 125   *caplist_p = *caplist ? caplist : 0;
 126
 127   return cap; /* and return the capability (if any) */
 128 }
 129
 130 /** Send a CAP \a subcmd list of capability changes to \a sptr.
 131  * If more than one line is necessary, each line before the last has
 132  * an added "*" parameter before that line's capability list.
 133  * @param[in] sptr Client receiving capability list.
 134  * @param[in] set Capabilities to show as set (with ack and sticky modifiers).
 135  * @param[in] rem Capabalities to show as removed (with no other modifier).
 136  * @param[in] subcmd Name of capability subcommand.
 137  */
 138 static int
 139 send_caplist(struct Client *sptr, const struct CapSet *set,
 140              const struct CapSet *rem, const char *subcmd)
 141 {
 142   char capbuf[BUFSIZE] = "", pfx[16];
 143   struct MsgBuf *mb;
 144   int i, loc, len, flags, pfx_len;
 145
 146   /* set up the buffer for the final LS message... */
 147   mb = msgq_make(sptr, "%:#C " MSG_CAP " %s :", &me, subcmd);
 148
 149   for (i = 0, loc = 0; i < CAPAB_LIST_LEN; i++) {
 150     flags = capab_list[i].flags;
 151     /* This is a little bit subtle, but just involves applying de
 152      * Morgan's laws to the obvious check: We must display the
 153      * capability if (and only if) it is set in \a rem or \a set, or
 154      * if both are null and the capability is hidden.
 155      */
 156     if (!(rem && CapHas(rem, capab_list[i].cap))
 157         && !(set && CapHas(set, capab_list[i].cap))
 158         && (rem || set || (flags & CAPFL_HIDDEN)))
 159       continue;
 160
 161     /* Build the prefix (space separator and any modifiers needed). */
 162     pfx_len = 0;
 163     if (loc)
 164       pfx[pfx_len++] = ' ';
 165     if (rem && CapHas(rem, capab_list[i].cap))
 166         pfx[pfx_len++] = '-';
 167     else {
 168       if (flags & CAPFL_PROTO)
 169         pfx[pfx_len++] = '~';
 170       if (flags & CAPFL_STICKY)
 171         pfx[pfx_len++] = '=';
 172     }
 173     pfx[pfx_len] = '\0';
 174
 175     len = capab_list[i].namelen + pfx_len; /* how much we'd add... */
 176     if (msgq_bufleft(mb) < loc + len + 2) { /* would add too much; must flush */
 177       sendcmdto_one(&me, CMD_CAP, sptr, "%s * :%s", subcmd, capbuf);
 178       capbuf[(loc = 0)] = '\0'; /* re-terminate the buffer... */
 179     }
 180
 181     loc += ircd_snprintf(0, capbuf + loc, sizeof(capbuf) - loc, "%s%s",
 182                          pfx, capab_list[i].name);
 183   }
 184
 185   msgq_append(0, mb, "%s", capbuf); /* append capabilities to the final cmd */
 186   send_buffer(sptr, mb, 0); /* send them out... */
 187   msgq_clean(mb); /* and release the buffer */
 188
 189   return 0; /* convenience return */
 190 }
 191
 192 static int
 193 cap_ls(struct Client *sptr, const char *caplist)
 194 {
 195   if (IsUnknown(sptr)) /* registration hasn't completed; suspend it... */
 196     cli_unreg(sptr) |= CLIREG_CAP;
 197
 198   return send_caplist(sptr, 0, 0, "LS"); /* send list of capabilities */
 199 }
 200
 201 static int
 202 cap_req(struct Client *sptr, const char *caplist)
 203 {
 204   const char *cl = caplist;
 205   struct capabilities *cap;
 206   struct CapSet set, rem;
 207   struct CapSet cs = *cli_capab(sptr); /* capability set */
 208   struct CapSet as = *cli_active(sptr); /* active set */
 209   int neg;
 210
 211   if (IsUnknown(sptr)) /* registration hasn't completed; suspend it... */
 212     cli_unreg(sptr) |= CLIREG_CAP;
 213
 214   memset(&set, 0, sizeof(set));
 215   memset(&rem, 0, sizeof(rem));
 216   while (cl) { /* walk through the capabilities list... */
 217     if (!(cap = find_cap(&cl, &neg)) /* look up capability... */
 218         || (!neg && (cap->flags & CAPFL_PROHIBIT)) /* is it prohibited? */
 219         || (neg && (cap->flags & CAPFL_STICKY))) { /* is it sticky? */
 220       sendcmdto_one(&me, CMD_CAP, sptr, "NAK :%s", caplist);
 221       return 0; /* can't complete requested op... */
 222     }
 223
 224     if (neg) { /* set or clear the capability... */
 225       CapSet(&rem, cap->cap);
 226       CapClr(&set, cap->cap);
 227       CapClr(&cs, cap->cap);
 228       if (!(cap->flags & CAPFL_PROTO))
 229         CapClr(&as, cap->cap);
 230     } else {
 231       CapClr(&rem, cap->cap);
 232       CapSet(&set, cap->cap);
 233       CapSet(&cs, cap->cap);
 234       if (!(cap->flags & CAPFL_PROTO))
 235         CapSet(&as, cap->cap);
 236     }
 237   }
 238
 239   /* Notify client of accepted changes and copy over results. */
 240   send_caplist(sptr, &set, &rem, "ACK");
 241   *cli_capab(sptr) = cs;
 242   *cli_active(sptr) = as;
 243
 244   return 0;
 245 }
 246
 247 static int
 248 cap_ack(struct Client *sptr, const char *caplist)
 249 {
 250   const char *cl = caplist;
 251   struct capabilities *cap;
 252   int neg;
 253
 254   /* Coming from the client, this generally indicates that the client
 255    * is using a new backwards-incompatible protocol feature.  As such,
 256    * it does not require further response from the server.
 257    */
 258   while (cl) { /* walk through the capabilities list... */
 259     if (!(cap = find_cap(&cl, &neg)) || /* look up capability... */
 260         (neg ? HasCap(sptr, cap->cap) : !HasCap(sptr, cap->cap))) /* uh... */
 261       continue;
 262
 263     if (neg) /* set or clear the active capability... */
 264       CapClr(cli_active(sptr), cap->cap);
 265     else
 266       CapSet(cli_active(sptr), cap->cap);
 267   }
 268
 269   return 0;
 270 }
 271
 272 static int
 273 cap_clear(struct Client *sptr, const char *caplist)
 274 {
 275   struct CapSet cleared;
 276   struct capabilities *cap;
 277   unsigned int ii;
 278
 279   /* XXX: If we ever add a capab list sorted by capab value, it would
 280    * be good cache-wise to use it here. */
 281   memset(&cleared, 0, sizeof(cleared));
 282   for (ii = 0; ii < CAPAB_LIST_LEN; ++ii) {
 283     cap = &capab_list[ii];
 284     /* Only clear active non-sticky capabilities. */
 285     if (!HasCap(sptr, cap->cap) || (cap->flags & CAPFL_STICKY))
 286       continue;
 287     CapSet(&cleared, cap->cap);
 288     CapClr(cli_capab(sptr), cap->cap);
 289     if (!(cap->flags & CAPFL_PROTO))
 290       CapClr(cli_active(sptr), cap->cap);
 291   }
 292   send_caplist(sptr, 0, &cleared, "ACK");
 293
 294   return 0;
 295 }
 296
 297 static int
 298 cap_end(struct Client *sptr, const char *caplist)
 299 {
 300   if (!IsUnknown(sptr)) /* registration has completed... */
 301     return 0; /* so just ignore the message... */
 302
 303   cli_unreg(sptr) &= ~CLIREG_CAP; /* capability negotiation is now done... */
 304
 305   if (!cli_unreg(sptr)) /* if client is now done... */
 306     return register_user(sptr, sptr, cli_name(sptr), cli_user(sptr)->username);
 307
 308   return 0; /* Can't do registration yet... */
 309 }
 310
 311 static int
 312 cap_list(struct Client *sptr, const char *caplist)
 313 {
 314   /* Send the list of the client's capabilities */
 315   return send_caplist(sptr, cli_capab(sptr), 0, "LIST");
 316 }
 317
 318 static struct subcmd {
 319   char *cmd;
 320   int (*proc)(struct Client *sptr, const char *caplist);
 321 } cmdlist[] = {
 322   { "ACK",   cap_ack   },
 323   { "CLEAR", cap_clear },
 324   { "END",   cap_end   },
 325   { "LIST",  cap_list  },
 326   { "LS",    cap_ls    },
 327   { "NAK",   0         },
 328   { "REQ",   cap_req   }
 329 };
 330
 331 static int
 332 subcmd_search(const char *cmd, const struct subcmd *elem)
 333 {
 334   return ircd_strcmp(cmd, elem->cmd);
 335 }
 336
 337 /** Handle a capability request or response from a client.
 338  * @param[in] cptr Client that sent us the message.
 339  * @param[in] sptr Original source of message.
 340  * @param[in] parc Number of arguments.
 341  * @param[in] parv Argument vector.
 342  * @see \ref m_functions
 343  */
 344 int
 345 m_cap(struct Client* cptr, struct Client* sptr, int parc, char* parv[])
 346 {
 347   char *subcmd, *caplist = 0;
 348   struct subcmd *cmd;
 349
 350   if (parc < 2) /* a subcommand is required */
 351     return 0;
 352   subcmd = parv[1];
 353   if (parc > 2) /* a capability list was provided */
 354     caplist = parv[2];
 355
 356   /* find the subcommand handler */
 357   if (!(cmd = (struct subcmd *)bsearch(subcmd, cmdlist,
 358                                        sizeof(cmdlist) / sizeof(struct subcmd),
 359                                        sizeof(struct subcmd),
 360                                        (bqcmp)subcmd_search)))
 361     return send_reply(sptr, ERR_UNKNOWNCAPCMD, subcmd);
 362
 363   /* then execute it... */
 364   return cmd->proc ? (cmd->proc)(sptr, caplist) : 0;
 365 }