release/src/router/xl2tpd/misc.c

   1 /*
   2  * Layer Two Tunnelling Protocol Daemon
   3  * Copyright (C) 1998 Adtran, Inc.
   4  * Copyright (C) 2002 Jeff McAdams
   5  *
   6  * Mark Spencer
   7  *
   8  * This software is distributed under the terms
   9  * of the GPL, which you should have received
  10  * along with this source.
  11  *
  12  * Miscellaneous but important functions
  13  *
  14  */
  15
  16 #include <unistd.h>
  17 #include <sys/types.h>
  18 #include <sys/stat.h>
  19 #include <fcntl.h>
  20 #include <stdarg.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <errno.h>
  24 #include <string.h>
  25 #include <syslog.h>
  26 #if defined(SOLARIS)
  27 # include <varargs.h>
  28 #endif
  29 #include <netinet/in.h>
  30 #include "l2tp.h"
  31
  32 /* prevent deadlock that occurs when a signal handler, which interrupted a
  33  * call to syslog(), attempts to call syslog(). */
  34 static int syslog_nesting = 0;
  35 #define SYSLOG_CALL(code) do {      \
  36     if (++syslog_nesting < 2) {     \
  37         code;                       \
  38     }                               \
  39     --syslog_nesting;               \
  40 } while(0)
  41
  42 void init_log()
  43 {
  44     static int logopen=0;
  45
  46     if(!logopen) {
  47         SYSLOG_CALL( openlog (BINARY, LOG_PID, LOG_DAEMON) );
  48         logopen=1;
  49     }
  50 }
  51
  52 void l2tp_log (int level, const char *fmt, ...)
  53 {
  54     char buf[256];
  55     va_list args;
  56     va_start (args, fmt);
  57     vsnprintf (buf, sizeof (buf), fmt, args);
  58     va_end (args);
  59
  60     if(gconfig.daemon) {
  61         init_log();
  62         SYSLOG_CALL( syslog (level, "%s", buf) );
  63     } else {
  64         fprintf(stderr, "xl2tpd[%d]: %s", getpid(), buf);
  65     }
  66 }
  67
  68 void set_error (struct call *c, int error, const char *fmt, ...)
  69 {
  70     va_list args;
  71     va_start (args, fmt);
  72     c->error = error;
  73     c->result = RESULT_ERROR;
  74     c->needclose = -1;
  75     vsnprintf (c->errormsg, sizeof (c->errormsg), fmt, args);
  76     if (c->errormsg[strlen (c->errormsg) - 1] == '\n')
  77         c->errormsg[strlen (c->errormsg) - 1] = 0;
  78     va_end (args);
  79 }
  80
  81 struct buffer *new_buf (int size)
  82 {
  83     struct buffer *b = malloc (sizeof (struct buffer));
  84
  85     if (!b || !size || size < 0)
  86         return NULL;
  87     b->rstart = malloc (size);
  88     if (!b->rstart)
  89     {
  90         free (b);
  91         return NULL;
  92     }
  93     b->start = b->rstart;
  94     b->rend = b->rstart + size - 1;
  95     b->len = size;
  96     b->maxlen = size;
  97     return b;
  98 }
  99
 100 inline void recycle_buf (struct buffer *b)
 101 {
 102     b->start = b->rstart;
 103     b->len = b->maxlen;
 104 }
 105
 106 #define bufferDumpWIDTH 16
 107 void bufferDump (unsigned char *buf, int buflen)
 108 {
 109     int i = 0, j = 0;
 110     /* we need TWO characters to DISPLAY ONE byte */
 111     char line[2 * bufferDumpWIDTH + 1], *c;
 112
 113     for (i = 0; i < buflen / bufferDumpWIDTH; i++)
 114     {
 115         c = line;
 116         for (j = 0; j < bufferDumpWIDTH; j++)
 117         {
 118           sprintf (c, "%02x ", (buf[i * bufferDumpWIDTH + j]) & 0xff);
 119             c++;
 120             c++;                /* again two characters to display ONE byte */
 121         }
 122         *c = '\0';
 123         l2tp_log (LOG_WARNING,
 124                   "%s: buflen=%d, buffer[%d]: *%s*\n", __FUNCTION__,
 125                   buflen, i, line);
 126     }
 127
 128     c = line;
 129     for (j = 0; j < buflen % bufferDumpWIDTH; j++)
 130     {
 131         sprintf (c, "%02x ",
 132                  buf[(buflen / bufferDumpWIDTH) * bufferDumpWIDTH +
 133                      j] & 0xff);
 134         c++;
 135         c++;
 136     }
 137     if (c != line)
 138     {
 139         *c = '\0';
 140         l2tp_log (LOG_WARNING,
 141                   "%s:             buffer[%d]: *%s*\n", __FUNCTION__, i,
 142                   line);
 143     }
 144 }
 145
 146 void do_packet_dump (struct buffer *buf)
 147 {
 148     int x;
 149     unsigned char *c = buf->start;
 150     printf ("packet dump: \nHEX: { ");
 151     for (x = 0; x < buf->len; x++)
 152     {
 153         printf ("%.2X ", *c);
 154         c++;
 155     };
 156     printf ("}\nASCII: { ");
 157     c = buf->start;
 158     for (x = 0; x < buf->len; x++)
 159     {
 160         if (*c > 31 && *c < 127)
 161         {
 162             putchar (*c);
 163         }
 164         else
 165         {
 166             putchar (' ');
 167         }
 168         c++;
 169     }
 170     printf ("}\n");
 171 }
 172
 173 inline void swaps (void *buf_v, int len)
 174 {
 175 #ifdef __alpha
 176     /* Reverse byte order alpha is little endian so lest save a step.
 177        to make things work out easier */
 178     int x;
 179     unsigned char t1;
 180     unsigned char *tmp = (_u16 *) buf_v;
 181     for (x = 0; x < len; x += 2)
 182     {
 183         t1 = tmp[x];
 184         tmp[x] = tmp[x + 1];
 185         tmp[x + 1] = t1;
 186     }
 187 #else
 188
 189     /* Reverse byte order (if proper to do so)
 190        to make things work out easier */
 191     int x;
 192         struct hw { _u16 s; } __attribute__ ((packed)) *p = (struct hw *) buf_v;
 193         for (x = 0; x < len / 2; x++, p++)
 194                 p->s = ntohs(p->s);
 195 #endif
 196 }
 197
 198
 199
 200 inline void toss (struct buffer *buf)
 201 {
 202     /*
 203      * Toss a frame and free up the buffer that contained it
 204      */
 205
 206     free (buf->rstart);
 207     free (buf);
 208 }
 209
 210 inline void safe_copy (char *a, char *b, int size)
 211 {
 212     /* Copies B into A (assuming A holds MAXSTRLEN bytes)
 213        safely */
 214     strncpy (a, b, MIN (size, MAXSTRLEN - 1));
 215     a[MIN (size, MAXSTRLEN - 1)] = '\000';
 216 }
 217
 218 struct ppp_opts *add_opt (struct ppp_opts *option, char *fmt, ...)
 219 {
 220     va_list args;
 221     struct ppp_opts *new, *last;
 222     new = (struct ppp_opts *) malloc (sizeof (struct ppp_opts));
 223     if (!new)
 224     {
 225         l2tp_log (LOG_WARNING,
 226                   "%s : Unable to allocate ppp option memory.  Expect a crash\n",
 227                   __FUNCTION__);
 228         return NULL;
 229     }
 230     new->next = NULL;
 231     va_start (args, fmt);
 232     vsnprintf (new->option, sizeof (new->option), fmt, args);
 233     va_end (args);
 234     if (option)
 235     {
 236         last = option;
 237         while (last->next)
 238             last = last->next;
 239         last->next = new;
 240         return option;
 241     }
 242     else
 243         return new;
 244 }
 245 void opt_destroy (struct ppp_opts *option)
 246 {
 247     struct ppp_opts *tmp;
 248     while (option)
 249     {
 250         tmp = option->next;
 251         free (option);
 252         option = tmp;
 253     };
 254 }
 255
 256 int get_egd_entropy(char *buf, int count)
 257 {
 258     return -1;
 259 }
 260
 261 int get_sys_entropy(unsigned char *buf, int count)
 262 {
 263     /*
 264      * This way of filling buf with rand() generated data is really
 265      * fairly inefficient from a function call point of view...rand()
 266      * returns four bytes of data (on most systems, sizeof(int))
 267      * and we end up only using 1 byte of it (sizeof(char))...ah
 268      * well...it was a *whole* lot easier to code this way...suggestions
 269      * for improvements are, of course, welcome
 270      */
 271     int counter;
 272     for (counter = 0; counter < count; counter++)
 273     {
 274         buf[counter] = (char)rand();
 275     }
 276 #ifdef DEBUG_ENTROPY
 277     bufferDump (buf, count);
 278 #endif
 279     return count;
 280 }
 281
 282 int get_dev_entropy(unsigned char *buf, int count)
 283 {
 284     int devrandom;
 285     ssize_t entropy_amount;
 286
 287     devrandom = open ("/dev/urandom", O_RDONLY | O_NONBLOCK);
 288     if (devrandom == -1)
 289     {
 290 #ifdef DEBUG_ENTROPY
 291         l2tp_log(LOG_WARNING, "%s: couldn't open /dev/urandom,"
 292                       "falling back to rand()\n",
 293                       __FUNCTION__);
 294 #endif
 295         return get_sys_entropy(buf, count);
 296     }
 297     entropy_amount = read(devrandom, buf, count);
 298     close(devrandom);
 299     return entropy_amount;
 300 }
 301
 302 int get_entropy (unsigned char *buf, int count)
 303 {
 304     if (rand_source == RAND_SYS)
 305     {
 306         return get_sys_entropy(buf, count);
 307     }
 308     else if (rand_source == RAND_DEV)
 309     {
 310         return get_dev_entropy(buf, count);
 311     }
 312     else if (rand_source == RAND_EGD)
 313     {
 314         l2tp_log(LOG_WARNING,
 315                  "%s: EGD Randomness source not yet implemented\n",
 316                 __FUNCTION__);
 317         return -1;
 318     }
 319     else
 320     {
 321             l2tp_log(LOG_WARNING,
 322                      "%s: Invalid Randomness source specified (%d)\n",
 323                      __FUNCTION__, rand_source);
 324             return -1;
 325     }
 326 }