#include "u.h"
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "errno.h"
#include "arp.h"
#include "ipdat.h"
#include "devtab.h"
/*
* All ip numbers and masks are stored as ulongs.
* All interfaces to this code uses the standard byte
* string representation.
*/
typedef struct Iproute Iproute;
typedef struct Iprtab Iprtab;
enum
{
Nroutes= 256,
};
/*
* routes
*/
struct Iproute {
ulong dst;
ulong gate;
ulong mask;
Iproute *next;
int inuse;
};
struct Iprtab {
Lock;
int n; /* number of valid routes */
Iproute *first; /* list of valid routes */
Iproute r[Nroutes]; /* all routes */
};
Iprtab iprtab;
/*
* The chosen route is the one obeys the constraint
* r->mask & dst == r->dst
*
* If there are several matches, the one whose mask has the most
* leading ones (and hence is the most specific) wins. This is
* forced by storing the routes in decreasing number of ones order
* and returning the first match. The default gateway has no ones
* in the mask and is thus the last matched.
*/
void
iproute(uchar *dst, uchar *gate)
{
Iproute *r;
ulong udst;
udst = nhgetl(dst);
if((udst&Mymask) == (Myip&Mymask)){
memmove(gate, dst, 4);
return;
}
/*
* first check routes
*/
for(r = iprtab.first; r; r = r->next){
if((r->mask&udst) == r->dst){
hnputl(gate, r->gate);
return;
}
}
/*
* else just return the same address
*/
memmove(gate, dst, 4);
}
/*
* Add a route, create a mask if the first mask is 0.
*
* All routes are stored sorted by the length of leading
* ones in the mask.
*
* NOTE: A default route has an all zeroes mask and dst.
*/
void
ipaddroute(ulong dst, ulong mask, ulong gate)
{
Iproute *r, *e, *free;
int i;
/*
* filter out impossible requests
*/
if((dst&mask) != dst)
errors("bad ip route");
/*
* see if we already have a route for
* the destination
*/
lock(&iprtab);
free = 0;
for(r = iprtab.r; r < &iprtab.r[Nroutes]; r++){
if(r->inuse == 0){
free = r;
continue;
}
if(dst==r->dst && mask==r->mask){
r->gate = gate;
unlock(&iprtab);
return;
}
}
if(free == 0){
unlock(&iprtab);
errors("no free ip routes");
}
/*
* add the new route in sorted order
*/
free->dst = dst;
free->mask = mask;
free->gate = gate;
free->inuse = 1;
for(r = e = iprtab.first; r; r = r->next){
if(mask > r->mask)
break;
e = r;
}
free->next = r;
if(r == iprtab.first)
iprtab.first = free;
else
e->next = free;
iprtab.n++;
unlock(&iprtab);
}
/*
* remove a route
*/
void
ipremroute(ulong dst, ulong mask)
{
Iproute *r, *e;
lock(&iprtab);
for(r = e = iprtab.first; r; r = r->next){
if(dst==r->dst && mask==r->mask){
if(r == iprtab.first)
iprtab.first = r->next;
else
e->next = r->next;
r->inuse = 0;
iprtab.n--;
break;
}
e = r;
}
unlock(&iprtab);
}
/*
* remove all routes
*/
void
ipflushroute(void)
{
Iproute *r;
lock(&iprtab);
for(r = iprtab.first; r; r = r->next)
r->inuse = 0;
iprtab.first = 0;
iprtab.n = 0;
unlock(&iprtab);
}
/*
* device interface
*/
enum{
Qdir,
Qdata,
};
Dirtab iproutetab[]={
"iproute", Qdata, 0, 0600,
};
#define Niproutetab (sizeof(iproutetab)/sizeof(Dirtab))
void
iproutereset(void)
{
}
void
iprouteinit(void)
{
}
Chan *
iprouteattach(char *spec)
{
return devattach('R', spec);
}
Chan *
iprouteclone(Chan *c, Chan *nc)
{
return devclone(c, nc);
}
int
iproutewalk(Chan *c, char *name)
{
return devwalk(c, name, iproutetab, (long)Niproutetab, devgen);
}
void
iproutestat(Chan *c, char *db)
{
devstat(c, db, iproutetab, (long)Niproutetab, devgen);
}
Chan *
iprouteopen(Chan *c, int omode)
{
if(c->qid.path == CHDIR){
if(omode != OREAD)
error(Eperm);
}
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
return c;
}
void
iproutecreate(Chan *c, char *name, int omode, ulong perm)
{
error(Eperm);
}
void
iprouteremove(Chan *c)
{
error(Eperm);
}
void
iproutewstat(Chan *c, char *dp)
{
error(Eperm);
}
void
iprouteclose(Chan *c)
{
}
#define IPR_ENTRYLEN 54
#define PAD " "
long
iprouteread(Chan *c, void *a, long n)
{
char buf[IPR_ENTRYLEN*3];
Iproute *r;
int part, bytes, size;
uchar dst[4], mask[4], gate[4];
switch((int)(c->qid.path&~CHDIR)){
case Qdir:
return devdirread(c, a, n, iproutetab, Niproutetab, devgen);
case Qdata:
lock(&iprtab);
part = c->offset/IPR_ENTRYLEN;
for(r = iprtab.first; part && r; r = r->next)
part--;
bytes = c->offset;
while(r && bytes < iprtab.n*IPR_ENTRYLEN && n){
part = bytes%IPR_ENTRYLEN;
hnputl(dst, r->dst);
hnputl(mask, r->mask);
hnputl(gate, r->gate);
sprint(buf,"%d.%d.%d.%d & %d.%d.%d.%d -> %d.%d.%d.%d%s",
dst[0], dst[1], dst[2], dst[3],
mask[0], mask[1], mask[2], mask[3],
gate[0], gate[1], gate[2], gate[3],
PAD);
buf[IPR_ENTRYLEN-1] = '\n';
size = IPR_ENTRYLEN - part;
if(size > n)
size = n;
memmove(a, buf+part, size);
a = (void *)((int)a + size);
n -= size;
bytes += size;
r = r->next;
}
unlock(&iprtab);
return bytes - c->offset;
break;
default:
n=0;
break;
}
return n;
}
long
iproutewrite(Chan *c, char *a, long n)
{
char buf[IPR_ENTRYLEN];
char *field[4];
Ipaddr mask, dst, gate;
int m;
switch((int)(c->qid.path&~CHDIR)){
case Qdata:
strncpy(buf, a, sizeof buf);
m = getfields(buf, field, 4, ' ');
if(strncmp(field[0], "flush", 5) == 0)
ipflushroute();
else if(strcmp(field[0], "add") == 0){
switch(m){
case 4:
dst = ipparse(field[1]);
mask = ipparse(field[2]);
gate = ipparse(field[3]);
ipaddroute(dst, mask, gate);
break;
case 3:
dst = ipparse(field[1]);
gate = ipparse(field[2]);
ipaddroute(dst, classmask[dst>>30], gate);
break;
default:
error(Ebadarg);
}
} else if(strcmp(field[0], "delete") == 0){
switch(m){
case 3:
dst = ipparse(field[1]);
mask = ipparse(field[2]);
ipremroute(dst, mask);
break;
case 2:
dst = ipparse(field[1]);
ipremroute(dst, classmask[dst>>30]);
break;
default:
error(Ebadarg);
}
}
break;
default:
error(Ebadusefd);
}
return n;
}