4.3BSD - /usr/src/new/pathalias/addlink.c

   1: /* pathalias -- by steve bellovin, as told to peter honeyman */
   2: #ifndef lint
   3: static char *sccsid = "@(#)addlink.c	8.1 (down!honey) 86/01/19";
   4: #endif lint
   5: 
   6: #include "def.h"
   7: 
   8: static link *Trace[NTRACE];
   9: static int  Tracecount;
  10: 
  11: link    *
  12: addlink(from, to, cost, netchar, netdir)
  13: node    *from;
  14: register node   *to;
  15: Cost    cost;
  16: char    netchar;
  17: char    netdir;
  18: {
  19:     register link   *l, *prev = 0;
  20: 
  21:     if (Tflag)
  22:         ltrace(from, to, cost, netchar, netdir);
  23:     /* maintain uniqueness for dead links (only) */
  24:     for (l = from->n_link; l && l->l_flag & LDEAD; l = l->l_next) {
  25:         if (to == l->l_to) {
  26:             /* what the hell, use cheaper cost */
  27:             if (cost < l->l_cost) {
  28:                 l->l_cost = cost;
  29:                 netbits(l, netchar, netdir);
  30:             }
  31:             return(l);
  32:         }
  33:         prev = l;
  34:     }
  35: 
  36:     /* allocate and link in the new link struct */
  37:     l = newlink();
  38:     if (cost != INF)    /* ignore back links */
  39:         Lcount++;
  40:     if (prev) {
  41:         l->l_next = prev->l_next;
  42:         prev->l_next = l;
  43:     } else {
  44:         l->l_next = from->n_link;
  45:         from->n_link = l;
  46:     }
  47: 
  48:     l->l_to = to;
  49:     l->l_cost = cost;
  50:     if (netchar == 0) {
  51:         netchar = DEFNET;
  52:         netdir = DEFDIR;
  53:     }
  54:     netbits(l, netchar, netdir);
  55: 
  56:     return(l);
  57: }
  58: 
  59: link    *
  60: addgateway(from, to, cost, netchar, netdir)
  61: node    *from;
  62: node    *to;
  63: Cost    cost;
  64: char    netchar;
  65: char    netdir;
  66: {
  67:     register link   *l;
  68: 
  69:     l = addlink(from, to, cost, netchar, netdir);
  70:     l->l_flag |= LGATEWAY;
  71:     return(l);
  72: }
  73: 
  74: deadlink(s)
  75: char    *s;
  76: {
  77:     char    *t, c;
  78:     link    *l;
  79: 
  80:     t = index(s, '!');
  81:     if (t) {
  82:         c = *t;
  83:         *t = 0;
  84:         l = addlink(addnode(s), addnode(t + 1), INF / 2, c, DEFDIR);
  85:         l->l_flag |= LDEAD;
  86:     } else
  87:         addnode(s)->n_flag |= NDEAD;
  88: }
  89: 
  90: netbits(l, netchar, netdir)
  91: link    *l;
  92: char    netchar, netdir;
  93: {
  94:     char    *nptr;
  95: 
  96:     if ((nptr = index(Netchars, netchar)) == 0) {
  97:         fprintf(stderr, "%s: unknown network operator: %c\n",
  98:                                 ProgName, netchar);
  99:         badmagic(1);
 100:     }
 101:     l->l_flag &= ~(LNETCHARS|LDIR);
 102:     l->l_flag |= (nptr - Netchars) | dirbits(netdir);
 103: }
 104: 
 105: tracelink(arg)
 106: char    *arg;
 107: {
 108:     char    *bang;
 109:     link    *l;
 110: 
 111:     if (Tracecount >= NTRACE)
 112:         return(-1);
 113:     l = newlink();
 114:     bang = index(arg, '!');
 115:     if (bang) {
 116:         *bang = 0;
 117:         l->l_to = addnode(bang+1);
 118:     } else
 119:         l->l_to = 0;
 120: 
 121:     l->l_from = (link *) addnode(arg);
 122:     Trace[Tracecount++] = l;
 123:     return(0);
 124: }
 125: 
 126: STATIC
 127: ltrace(from, to, cost, netchar, netdir)
 128: node    *from, *to;
 129: Cost    cost;
 130: char    netchar;
 131: char    netdir;
 132: {
 133:     link    *l;
 134:     int i;
 135: 
 136:     for (i = 0; i < Tracecount; i++) {
 137:         l = Trace[i];
 138:         /* overkill -- you asked for it! */
 139:         if ((l->l_to == 0
 140:           && (from == (node *) l->l_from || to == (node *) l->l_from))
 141:          || (from == (node *) l->l_from && to == l->l_to)
 142:          || (to == (node *) l->l_from && from == l->l_to)) {
 143:             ltrprint(from, to, cost, netchar, netdir);
 144:             return;
 145:         }
 146:     }
 147: }
 148: 
 149: /* print a trace item */
 150: STATIC
 151: ltrprint(from, to, cost, netchar, netdir)
 152: node    *from, *to;
 153: Cost    cost;
 154: char    netchar;
 155: char    netdir;
 156: {
 157:     char    buf[256], *bptr = buf;
 158: 
 159:     strcpy(bptr, from->n_name);
 160:     bptr += strlen(bptr);
 161:     *bptr++ = ' ';
 162:     if (netdir == LRIGHT)           /* @% */
 163:         *bptr++ = netchar;
 164:     strcpy(bptr, to->n_name);
 165:     bptr += strlen(bptr);
 166:     if (netdir == LLEFT)            /* !: */
 167:         *bptr++ = netchar;
 168:     sprintf(bptr, "(%ld)", cost);
 169:     yyerror(buf);
 170: }
 171: 
 172: atrace(n1, n2)
 173: node    *n1, *n2;
 174: {
 175:     link    *l;
 176:     int i;
 177:     char    buf[256];
 178: 
 179:     for (i = 0; i < Tracecount; i++) {
 180:         l = Trace[i];
 181:         if (l->l_to == 0 && ((node *) l->l_from == n1 || (node *) l->l_from == n2)) {
 182:             sprintf(buf, "%s = %s", n1->n_name, n2->n_name);
 183:             yyerror(buf);
 184:             return;
 185:         }
 186:     }
 187: }

Defined functions

Defined variables