listener.c

   1 /*
   2  * Dropbear SSH
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * All rights reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE. */
  24
  25 #include "includes.h"
  26 #include "listener.h"
  27 #include "session.h"
  28 #include "dbutil.h"
  29
  30 void listeners_initialise() {
  31
  32         /* just one slot to start with */
  33         ses.listeners = (struct Listener**)m_malloc(sizeof(struct Listener*));
  34         ses.listensize = 1;
  35         ses.listeners[0] = NULL;
  36
  37 }
  38
  39 void set_listener_fds(fd_set * readfds) {
  40
  41         unsigned int i, j;
  42         struct Listener *listener;
  43
  44         /* check each in turn */
  45         for (i = 0; i < ses.listensize; i++) {
  46                 listener = ses.listeners[i];
  47                 if (listener != NULL) {
  48                         for (j = 0; j < listener->nsocks; j++) {
  49                                 FD_SET(listener->socks[j], readfds);
  50                         }
  51                 }
  52         }
  53 }
  54
  55
  56 void handle_listeners(fd_set * readfds) {
  57
  58         unsigned int i, j;
  59         struct Listener *listener;
  60         int sock;
  61
  62         /* check each in turn */
  63         for (i = 0; i < ses.listensize; i++) {
  64                 listener = ses.listeners[i];
  65                 if (listener != NULL) {
  66                         for (j = 0; j < listener->nsocks; j++) {
  67                                 sock = listener->socks[j];
  68                                 if (FD_ISSET(sock, readfds)) {
  69                                         listener->acceptor(listener, sock);
  70                                 }
  71                         }
  72                 }
  73         }
  74 } /* Woo brace matching */
  75
  76
  77 /* acceptor(int fd, void* typedata) is a function to accept connections,
  78  * cleanup(void* typedata) happens when cleaning up */
  79 struct Listener* new_listener(int socks[], unsigned int nsocks,
  80                 int type, void* typedata,
  81                 void (*acceptor)(struct Listener* listener, int sock),
  82                 void (*cleanup)(struct Listener*)) {
  83
  84         unsigned int i, j;
  85         struct Listener *newlisten = NULL;
  86         /* try get a new structure to hold it */
  87         for (i = 0; i < ses.listensize; i++) {
  88                 if (ses.listeners[i] == NULL) {
  89                         break;
  90                 }
  91         }
  92
  93         /* or create a new one */
  94         if (i == ses.listensize) {
  95                 if (ses.listensize > MAX_LISTENERS) {
  96                         TRACE(("leave newlistener: too many already"))
  97                         for (j = 0; j < nsocks; j++) {
  98                                 close(socks[i]);
  99                         }
 100                         return NULL;
 101                 }
 102
 103                 ses.listeners = (struct Listener**)m_realloc(ses.listeners,
 104                                 (ses.listensize+LISTENER_EXTEND_SIZE)
 105                                 *sizeof(struct Listener*));
 106
 107                 ses.listensize += LISTENER_EXTEND_SIZE;
 108
 109                 for (j = i; j < ses.listensize; j++) {
 110                         ses.listeners[j] = NULL;
 111                 }
 112         }
 113
 114         for (j = 0; j < nsocks; j++) {
 115                 ses.maxfd = MAX(ses.maxfd, socks[j]);
 116         }
 117
 118         TRACE(("new listener num %d ", i))
 119
 120         newlisten = (struct Listener*)m_malloc(sizeof(struct Listener));
 121         newlisten->index = i;
 122         newlisten->type = type;
 123         newlisten->typedata = typedata;
 124         newlisten->nsocks = nsocks;
 125         memcpy(newlisten->socks, socks, nsocks * sizeof(int));
 126         newlisten->acceptor = acceptor;
 127         newlisten->cleanup = cleanup;
 128
 129         ses.listeners[i] = newlisten;
 130         return newlisten;
 131 }
 132
 133 /* Return the first listener which matches the type-specific comparison
 134  * function. Particularly needed for global requests, like tcp */
 135 struct Listener * get_listener(int type, void* typedata,
 136                 int (*match)(void*, void*)) {
 137
 138         unsigned int i;
 139         struct Listener* listener;
 140
 141         for (i = 0, listener = ses.listeners[i]; i < ses.listensize; i++) {
 142                 if (listener->type == type
 143                                 && match(typedata, listener->typedata)) {
 144                         return listener;
 145                 }
 146         }
 147
 148         return NULL;
 149 }
 150
 151 void remove_listener(struct Listener* listener) {
 152
 153         unsigned int j;
 154
 155         if (listener->cleanup) {
 156                 listener->cleanup(listener);
 157         }
 158
 159         for (j = 0; j < listener->nsocks; j++) {
 160                 close(listener->socks[j]);
 161         }
 162         ses.listeners[listener->index] = NULL;
 163         m_free(listener);
 164
 165 }