linuxstreams/wviproute.cc

   1 /*
   2  * Worldvisions Weaver Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * The WvIPRoute and WvIPRouteList class, a quick (mostly hackish) attempt
   6  * at a way to read the Linux kernel routing table.
   7  */
   8 #include "wviproute.h"
   9 #include "wvpipe.h"
  10 #include "wvinterface.h"
  11 #include "wvfile.h"
  12 #include "wvstringlist.h"
  13
  14 #include <net/route.h>
  15 #include <ctype.h>
  16
  17 WvIPRoute::WvIPRoute(WvStringParm _ifc, const WvIPNet &_net,
  18                      const WvIPAddr &_gate, int _metric,
  19                      WvStringParm _table)
  20     : ifc(_ifc), ip(_net), gateway(_gate), table(_table), src()
  21 {
  22     metric = _metric;
  23 }
  24
  25
  26 WvIPRoute::operator WvString() const
  27 {
  28     WvIPAddr zero;
  29     return WvString("%s via %s %s %s metric %s%s",
  30                     ip, ifc, gateway,
  31                     (src != zero ? WvString("src %s", src) : WvString("")),
  32                     metric,
  33                     (table != "default")
  34                       ? WvString(" (table %s)", table) : WvString(""));
  35 }
  36
  37
  38 bool WvIPRoute::operator== (const WvIPRoute &r2) const
  39 {
  40     return (ip.network() == r2.ip.network() && ip.netmask() == r2.ip.netmask()
  41             && gateway == r2.gateway
  42             && ifc == r2.ifc && metric == r2.metric
  43             && table == r2.table);
  44 }
  45
  46
  47
  48 /////////////////////////////////////// WvIPRouteList
  49
  50
  51 WvIPRouteList::WvIPRouteList() : log("Route Table", WvLog::Debug)
  52 {
  53     // nothing else to do
  54 }
  55
  56
  57 // Reads the kernel routing table, from /proc/net/route, and parses it into
  58 // A WvIPRouteList.  Also reads the kernel 2.1.x "policy routing" tables,
  59 // (via the "ip" command) and parses those routes.
  60 void WvIPRouteList::get_kernel()
  61 {
  62     char *line;
  63     WvString ifc, table, gate, addr, mask, src;
  64     int metric, flags;
  65     bool invalid;
  66     WvIPRoute *r;
  67     WvStringList words;
  68     WvStringList::Iter word(words);
  69
  70     // read each route information line from /proc/net/route; even though
  71     // "ip route list table all" returns all the same information plus more,
  72     // there's no guarantee that the ip command is available on all systems.
  73     WvFile kinfo("/proc/net/route", O_RDONLY);
  74     kinfo.getline();
  75     while ((line = kinfo.getline()) != NULL)
  76     {
  77         //log(WvLog::Debug2, "get_kern1: line: %s\n", line);
  78
  79         words.zap();
  80         words.split(line);
  81
  82         if (words.count() < 10)
  83             continue; // weird entry
  84
  85         word.rewind();
  86         word.next(); ifc   = *word;
  87         word.next(); addr  = *word;
  88         word.next(); gate  = *word;
  89         word.next(); flags = strtoul(*word, NULL, 16);
  90         word.next(); // refcnt
  91         word.next(); // use
  92         word.next(); metric = atoi(*word);
  93         word.next(); mask   = *word;
  94
  95         // routes appear in the list even when not "up" -- strange.
  96         if (!(flags & RTF_UP))
  97             continue;
  98
  99         // the addresses in /proc/net/route are in hex.  This here is some
 100         // pretty sicky type-munging...
 101         uint32_t a = strtoul(addr, NULL, 16), m = strtoul(mask, NULL, 16);
 102         uint32_t g = strtoul(gate, NULL, 16);
 103         WvIPAddr aa(a), mm(m);
 104         WvIPNet net(aa, mm);
 105         WvIPAddr gw(g);
 106
 107         r = new WvIPRoute(ifc, net, gw, metric, "default");
 108         append(r, true);
 109         //log(WvLog::Debug2, "get_kern1:  out: %s\n", *r);
 110     }
 111
 112     // add more data from the kernel "policy routing" default table
 113     const char *argv[] = { "ip", "route", "list", "table", "all", NULL };
 114     WvPipe defaults(argv[0], argv, false, true, false);
 115     while (defaults.isok() && (line = defaults.blocking_getline(-1)) != NULL)
 116     {
 117         //log(WvLog::Debug2, "get_kern2: line: %s\n", line);
 118
 119         invalid = false;
 120         ifc = gate = table = "";
 121         metric = 0;
 122
 123         words.zap();
 124         words.split(line);
 125
 126         if (words.count() < 3)
 127             continue; // weird entry
 128
 129         word.rewind();
 130         word.next();
 131         if (*word == "broadcast" || *word == "local")
 132             continue; // these lines are weird: skip them
 133
 134         WvIPNet net((*word == "default") ? WvString("0/0") : *word);
 135
 136         while (word.next())
 137         {
 138             WvString word1(*word);
 139             if (!word.next()) break;
 140             WvString word2(*word);
 141
 142             if (word1 == "table")
 143             {
 144                 if (word2 == "local")
 145                 {
 146                     invalid = true; // ignore 'local' table - too complex
 147                     break;
 148                 }
 149                 else
 150                     table = word2;
 151             }
 152             else if (word1 == "dev")
 153                 ifc = word2;
 154             else if (word1 == "via")
 155                 gate = word2;
 156             else if (word1 == "metric")
 157                 metric = word2.num();
 158             else if (word1 == "scope")
 159                 ; // ignore
 160             else if (word1 == "proto" && word2 == "kernel")
 161                 ; // ignore
 162             else if (word1 == "src")
 163                 src = word2;
 164             else
 165                 log(WvLog::Debug, "Unknown keyvalue: '%s' '%s' in (%s)\n",
 166                     word1, word2, line);
 167
 168             // ignore all other words - just use their defaults.
 169         }
 170
 171         // if no table keyword was given, it's the default "main" table, which
 172         // we already read from /proc/net/route.  Skip it.
 173         if (!table)
 174             continue;
 175
 176         if (!ifc)
 177         {
 178             log(WvLog::Debug2, "No interface given for this route; skipped.\n");
 179             continue;
 180         }
 181
 182         r = new WvIPRoute(ifc, net, gate ? WvIPAddr(gate) : WvIPAddr(),
 183                           metric, table);
 184         if (!!src)
 185                 r->src = src;
 186         append(r, true);
 187         //log(WvLog::Debug2, "get_kern2:  out: %s\n", *r);
 188     }
 189 }
 190
 191
 192 static WvString realtable(WvIPRoute &r)
 193 {
 194     if (!r.ip.is_default() && r.table == "default")
 195         return "main";
 196     else
 197         return r.table;
 198 }
 199
 200
 201 // we use an n-squared algorithm here, for no better reason than readability.
 202 void WvIPRouteList::set_kernel()
 203 {
 204     WvIPRouteList old_kern;
 205     old_kern.get_kernel();
 206
 207     Iter oi(old_kern), ni(*this);
 208
 209     // FIXME!!
 210     // Kernel 2.1.131: deleting a route with no gateway causes the kernel
 211     // to delete the _first_ route to that network, regardless of its
 212     // gateway.  This is probably to make things like "route del default"
 213     // more convenient.  However, it messes up if we add routes first, then
 214     // delete routes.
 215     //
 216     // Except for this problem, it makes more sense to add and then delete,
 217     // since we avoid races (we never completely remove a route to a host
 218     // we should be routing to).
 219
 220     // delete outdated routes.
 221     for (oi.rewind(); oi.next(); )
 222     {
 223         if (oi->metric == 99) continue; // "magic" metric for manual override
 224
 225         for (ni.rewind(); ni.next(); )
 226             if (*ni == *oi) break;
 227
 228         if (!ni.cur()) // hit end of list without finding a match
 229         {
 230             WvInterface i(oi->ifc);
 231             log("Del %s\n", *oi);
 232             i.delroute(oi->ip, oi->gateway, oi->metric, realtable(*oi));
 233         }
 234     }
 235
 236     // add any new routes.
 237     for (ni.rewind(); ni.next(); )
 238     {
 239         for (oi.rewind(); oi.next(); )
 240             if (*oi == *ni) break;
 241
 242         if (!oi.cur()) // hit end of list without finding a match
 243         {
 244             WvInterface i(ni->ifc);
 245             log("Add %s\n", *ni);
 246             i.addroute(ni->ip, ni->gateway, ni->src, ni->metric,
 247                         realtable(*ni));
 248         }
 249     }
 250 }
 251
 252
 253 WvIPRoute *WvIPRouteList::find(const WvIPAddr &addr)
 254 {
 255     Iter i(*this);
 256
 257     for (i.rewind(); i.next(); )
 258     {
 259         if (i->ip.includes(addr))
 260             return &i();
 261     }
 262
 263     return NULL;
 264 }