ref: d8a8ac237a5c08ce5a6fe990c213ffc0292a18dc
dir: /sys/src/9/ip/ethermedium.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "../port/netif.h"
#include "ip.h"
#include "ipv6.h"
typedef struct Etherhdr Etherhdr;
struct Etherhdr
{
uchar d[6];
uchar s[6];
uchar t[2];
};
static uchar ipbroadcast[IPaddrlen] = {
0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,
};
static uchar etherbroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
static void etherread4(void *a);
static void etherread6(void *a);
static void etherbind(Ipifc *ifc, int argc, char **argv);
static void etherunbind(Ipifc *ifc);
static void etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip);
static void etheraddmulti(Ipifc *ifc, uchar *a, uchar *ia);
static void etherremmulti(Ipifc *ifc, uchar *a, uchar *ia);
static void etherareg(Fs *f, Ipifc *ifc, Iplifc *lifc, uchar *ip);
static Block* multicastarp(Fs *f, Arpent *a, Medium*, uchar *mac);
static void sendarp(Ipifc *ifc, Arpent *a);
static void sendndp(Ipifc *ifc, Arpent *a);
static int multicastea(uchar *ea, uchar *ip);
static void recvarpproc(void*);
static void etherpref2addr(uchar *pref, uchar *ea);
Medium ethermedium =
{
.name= "ether",
.hsize= 14,
.mintu= 60,
.maxtu= 1514,
.maclen= 6,
.bind= etherbind,
.unbind= etherunbind,
.bwrite= etherbwrite,
.addmulti= etheraddmulti,
.remmulti= etherremmulti,
.areg= etherareg,
.pref2addr= etherpref2addr,
};
Medium gbemedium =
{
.name= "gbe",
.hsize= 14,
.mintu= 60,
.maxtu= 9014,
.maclen= 6,
.bind= etherbind,
.unbind= etherunbind,
.bwrite= etherbwrite,
.addmulti= etheraddmulti,
.remmulti= etherremmulti,
.areg= etherareg,
.pref2addr= etherpref2addr,
};
typedef struct Etherrock Etherrock;
struct Etherrock
{
Fs *f; /* file system we belong to */
Proc *arpp; /* arp process */
Proc *read4p; /* reading process (v4)*/
Proc *read6p; /* reading process (v6)*/
Chan *mchan4; /* Data channel for v4 */
Chan *achan; /* Arp channel */
Chan *cchan4; /* Control channel for v4 */
Chan *mchan6; /* Data channel for v6 */
Chan *cchan6; /* Control channel for v6 */
};
/*
* ethernet arp request
*/
enum
{
ARPREQUEST = 1,
ARPREPLY = 2,
};
typedef struct Etherarp Etherarp;
struct Etherarp
{
uchar d[6];
uchar s[6];
uchar type[2];
uchar hrd[2];
uchar pro[2];
uchar hln;
uchar pln;
uchar op[2];
uchar sha[6];
uchar spa[4];
uchar tha[6];
uchar tpa[4];
};
static char *nbmsg = "nonblocking";
/*
* called to bind an IP ifc to an ethernet device
* called with ifc wlock'd
*/
static void
etherbind(Ipifc *ifc, int argc, char **argv)
{
char addr[Maxpath], dir[Maxpath];
Etherrock *er;
Chan *c;
int n;
if(argc < 2)
error(Ebadarg);
/*
* get mac address
*/
snprint(addr, sizeof(addr), "%s/addr", argv[2]);
c = namec(addr, Aopen, OREAD, 0);
if(waserror()){
cclose(c);
nexterror();
}
n = devtab[c->type]->read(c, addr, sizeof(addr)-1, 0);
if(n < 0)
error(Eio);
addr[n] = 0;
if(parsemac(ifc->mac, addr, sizeof(ifc->mac)) != 6)
error("could not find mac address");
cclose(c);
poperror();
er = smalloc(sizeof(*er));
er->read4p = er->read6p = er->arpp = (void*)-1;
er->mchan4 = er->cchan4 = er->mchan6 = er->cchan6 = er->achan = nil;
er->f = ifc->conv->p->f;
if(waserror()){
if(er->mchan4 != nil)
cclose(er->mchan4);
if(er->cchan4 != nil)
cclose(er->cchan4);
if(er->mchan6 != nil)
cclose(er->mchan6);
if(er->cchan6 != nil)
cclose(er->cchan6);
if(er->achan != nil)
cclose(er->achan);
free(er);
nexterror();
}
/*
* open ipv4 conversation
*
* the dial will fail if the type is already open on
* this device.
*/
snprint(addr, sizeof(addr), "%s!0x800", argv[2]); /* ETIP4 */
er->mchan4 = chandial(addr, nil, dir, &er->cchan4);
/*
* make it non-blocking
*/
devtab[er->cchan4->type]->write(er->cchan4, nbmsg, strlen(nbmsg), 0);
/*
* open ipv6 conversation
*
* the dial will fail if the type is already open on
* this device.
*/
snprint(addr, sizeof(addr), "%s!0x86DD", argv[2]); /* ETIP6 */
er->mchan6 = chandial(addr, nil, dir, &er->cchan6);
/*
* make it non-blocking
*/
devtab[er->cchan6->type]->write(er->cchan6, nbmsg, strlen(nbmsg), 0);
/*
* open arp conversation
*/
snprint(addr, sizeof(addr), "%s!0x806", argv[2]); /* ETARP */
er->achan = chandial(addr, nil, nil, nil);
poperror();
ifc->arg = er;
kproc("etherread4", etherread4, ifc);
kproc("etherread6", etherread6, ifc);
kproc("recvarpproc", recvarpproc, ifc);
}
/*
* called with ifc wlock'd
*/
static void
etherunbind(Ipifc *ifc)
{
Etherrock *er = ifc->arg;
/* wait for readers to start */
while(er->arpp == (void*)-1 || er->read4p == (void*)-1 || er->read6p == (void*)-1)
tsleep(&up->sleep, return0, 0, 300);
if(er->read4p != nil)
postnote(er->read4p, 1, "unbind", 0);
if(er->read6p != nil)
postnote(er->read6p, 1, "unbind", 0);
if(er->arpp != nil)
postnote(er->arpp, 1, "unbind", 0);
/* wait for readers to die */
while(er->arpp != nil || er->read4p != nil || er->read6p != nil)
tsleep(&up->sleep, return0, 0, 300);
if(er->mchan4 != nil)
cclose(er->mchan4);
if(er->cchan4 != nil)
cclose(er->cchan4);
if(er->mchan6 != nil)
cclose(er->mchan6);
if(er->cchan6 != nil)
cclose(er->cchan6);
if(er->achan != nil)
cclose(er->achan);
free(er);
}
/*
* called by ipoput with a single block to write with ifc rlock'd
*/
static void
etherbwrite(Ipifc *ifc, Block *bp, int version, uchar *ip)
{
Etherhdr *eh;
Arpent *a;
uchar mac[6];
Etherrock *er = ifc->arg;
/* get mac address of destination */
a = arpget(er->f->arp, bp, version, ifc, ip, mac);
if(a != nil){
/* check for broadcast or multicast */
bp = multicastarp(er->f, a, ifc->m, mac);
if(bp == nil){
switch(version){
case V4:
sendarp(ifc, a);
break;
case V6:
sendndp(ifc, a);
break;
default:
panic("etherbwrite: version %d", version);
}
return;
}
}
/* make it a single block with space for the ether header */
bp = padblock(bp, ifc->m->hsize);
if(BLEN(bp) < ifc->mintu)
bp = adjustblock(bp, ifc->mintu);
eh = (Etherhdr*)bp->rp;
/* copy in mac addresses and ether type */
memmove(eh->s, ifc->mac, sizeof(eh->s));
memmove(eh->d, mac, sizeof(eh->d));
switch(version){
case V4:
eh->t[0] = 0x08;
eh->t[1] = 0x00;
devtab[er->mchan4->type]->bwrite(er->mchan4, bp, 0);
break;
case V6:
eh->t[0] = 0x86;
eh->t[1] = 0xDD;
devtab[er->mchan6->type]->bwrite(er->mchan6, bp, 0);
break;
default:
panic("etherbwrite2: version %d", version);
}
ifc->out++;
}
/*
* process to read from the ethernet
*/
static void
etherread4(void *a)
{
Ipifc *ifc;
Block *bp;
Etherrock *er;
ifc = a;
er = ifc->arg;
er->read4p = up; /* hide identity under a rock for unbind */
if(waserror()){
er->read4p = nil;
pexit("hangup", 1);
}
for(;;){
bp = devtab[er->mchan4->type]->bread(er->mchan4, ifc->maxtu, 0);
if(!canrlock(ifc)){
freeb(bp);
continue;
}
if(waserror()){
runlock(ifc);
nexterror();
}
ifc->in++;
if(ifc->lifc == nil || BLEN(bp) <= ifc->m->hsize)
freeb(bp);
else {
bp->rp += ifc->m->hsize;
ipiput4(er->f, ifc, bp);
}
runlock(ifc);
poperror();
}
}
/*
* process to read from the ethernet, IPv6
*/
static void
etherread6(void *a)
{
Ipifc *ifc;
Block *bp;
Etherrock *er;
ifc = a;
er = ifc->arg;
er->read6p = up; /* hide identity under a rock for unbind */
if(waserror()){
er->read6p = nil;
pexit("hangup", 1);
}
for(;;){
bp = devtab[er->mchan6->type]->bread(er->mchan6, ifc->maxtu, 0);
if(!canrlock(ifc)){
freeb(bp);
continue;
}
if(waserror()){
runlock(ifc);
nexterror();
}
ifc->in++;
if(ifc->lifc == nil || BLEN(bp) <= ifc->m->hsize)
freeb(bp);
else {
bp->rp += ifc->m->hsize;
ipiput6(er->f, ifc, bp);
}
runlock(ifc);
poperror();
}
}
static void
etheraddmulti(Ipifc *ifc, uchar *a, uchar *)
{
uchar mac[6];
char buf[64];
Etherrock *er = ifc->arg;
int version;
version = multicastea(mac, a);
sprint(buf, "addmulti %E", mac);
switch(version){
case V4:
devtab[er->cchan4->type]->write(er->cchan4, buf, strlen(buf), 0);
break;
case V6:
devtab[er->cchan6->type]->write(er->cchan6, buf, strlen(buf), 0);
break;
default:
panic("etheraddmulti: version %d", version);
}
}
static void
etherremmulti(Ipifc *ifc, uchar *a, uchar *)
{
uchar mac[6];
char buf[64];
Etherrock *er = ifc->arg;
int version;
version = multicastea(mac, a);
sprint(buf, "remmulti %E", mac);
switch(version){
case V4:
devtab[er->cchan4->type]->write(er->cchan4, buf, strlen(buf), 0);
break;
case V6:
devtab[er->cchan6->type]->write(er->cchan6, buf, strlen(buf), 0);
break;
default:
panic("etherremmulti: version %d", version);
}
}
/*
* send an ethernet arp
* (only v4, v6 uses the neighbor discovery, rfc1970)
*/
static void
sendarp(Ipifc *ifc, Arpent *a)
{
int n;
Block *bp;
Etherarp *e;
Etherrock *er = ifc->arg;
uchar targ[IPv4addrlen], src[IPv4addrlen];
/* don't do anything if it's been less than a second since the last */
if(NOW - a->ctime < 1000){
arprelease(er->f->arp, a);
return;
}
/* try to keep it around for a second more */
a->ctime = NOW;
/* remove all but the last message */
while((bp = a->hold) != nil){
if(bp == a->last)
break;
a->hold = bp->list;
freeblist(bp);
}
memmove(targ, a->ip+IPv4off, IPv4addrlen);
arprelease(er->f->arp, a);
if(!ipv4local(ifc, src, targ))
return;
n = sizeof(Etherarp);
if(n < ifc->m->mintu)
n = ifc->m->mintu;
bp = allocb(n);
memset(bp->rp, 0, n);
e = (Etherarp*)bp->rp;
memmove(e->tpa, targ, sizeof(e->tpa));
memmove(e->spa, src, sizeof(e->spa));
memmove(e->sha, ifc->mac, sizeof(e->sha));
memset(e->d, 0xff, sizeof(e->d)); /* ethernet broadcast */
memmove(e->s, ifc->mac, sizeof(e->s));
hnputs(e->type, ETARP);
hnputs(e->hrd, 1);
hnputs(e->pro, ETIP4);
e->hln = sizeof(e->sha);
e->pln = sizeof(e->spa);
hnputs(e->op, ARPREQUEST);
bp->wp += n;
devtab[er->achan->type]->bwrite(er->achan, bp, 0);
}
static void
sendndp(Ipifc *ifc, Arpent *a)
{
Block *bp;
Etherrock *er = ifc->arg;
/* don't do anything if it's been less than a second since the last */
if(NOW - a->ctime < ReTransTimer){
arprelease(er->f->arp, a);
return;
}
/* remove all but the last message */
while((bp = a->hold) != nil){
if(bp == a->last)
break;
a->hold = bp->list;
freeblist(bp);
}
ndpsendsol(er->f, ifc, a); /* unlocks arp */
}
/*
* send a gratuitous arp to refresh arp caches
*/
static void
sendgarp(Ipifc *ifc, uchar *ip)
{
int n;
Block *bp;
Etherarp *e;
Etherrock *er = ifc->arg;
n = sizeof(Etherarp);
if(n < ifc->m->mintu)
n = ifc->m->mintu;
bp = allocb(n);
memset(bp->rp, 0, n);
e = (Etherarp*)bp->rp;
memmove(e->tpa, ip+IPv4off, sizeof(e->tpa));
memmove(e->spa, ip+IPv4off, sizeof(e->spa));
memmove(e->sha, ifc->mac, sizeof(e->sha));
memset(e->d, 0xff, sizeof(e->d)); /* ethernet broadcast */
memmove(e->s, ifc->mac, sizeof(e->s));
hnputs(e->type, ETARP);
hnputs(e->hrd, 1);
hnputs(e->pro, ETIP4);
e->hln = sizeof(e->sha);
e->pln = sizeof(e->spa);
hnputs(e->op, ARPREQUEST);
bp->wp += n;
devtab[er->achan->type]->bwrite(er->achan, bp, 0);
}
static void
recvarp(Ipifc *ifc)
{
int n, forme;
Block *ebp, *rbp;
Etherarp *e, *r;
uchar ip[IPaddrlen];
static uchar eprinted[4];
Etherrock *er = ifc->arg;
ebp = devtab[er->achan->type]->bread(er->achan, ifc->maxtu, 0);
if(ebp == nil)
return;
if(!canrlock(ifc)){
freeb(ebp);
return;
}
e = (Etherarp*)ebp->rp;
switch(nhgets(e->op)) {
default:
break;
case ARPREPLY:
/* make sure not to enter multi/broadcat address */
if(e->sha[0] & 1)
break;
/* check for machine using my ip address */
v4tov6(ip, e->spa);
if(iplocalonifc(ifc, ip) != nil || ipproxyifc(er->f, ifc, ip)){
if(memcmp(e->sha, ifc->mac, sizeof(e->sha)) != 0){
print("arprep: 0x%E/0x%E also has ip addr %V\n",
e->s, e->sha, e->spa);
break;
}
}
/* refresh what we know about sender */
arpenter(er->f, V4, e->spa, e->sha, sizeof(e->sha), e->tpa, ifc, 1);
break;
case ARPREQUEST:
/* don't reply to multi/broadcat addresses */
if(e->sha[0] & 1)
break;
/* don't answer arps till we know who we are */
if(ifc->lifc == nil)
break;
/* check for machine using my ip or ether address */
v4tov6(ip, e->spa);
if(iplocalonifc(ifc, ip) != nil || ipproxyifc(er->f, ifc, ip)){
if(memcmp(e->sha, ifc->mac, sizeof(e->sha)) != 0){
if(memcmp(eprinted, e->spa, sizeof(e->spa)) != 0){
/* print only once */
print("arpreq: 0x%E also has ip addr %V\n",
e->sha, e->spa);
memmove(eprinted, e->spa, sizeof(e->spa));
}
break;
}
} else {
if(memcmp(e->sha, ifc->mac, sizeof(e->sha)) == 0){
print("arpreq: %V also has ether addr %E\n",
e->spa, e->sha);
break;
}
}
/*
* when request is for our address or systems we're proxying for,
* enter senders address into arp table and reply, otherwise just
* refresh the senders address.
*/
v4tov6(ip, e->tpa);
forme = iplocalonifc(ifc, ip) != nil || ipproxyifc(er->f, ifc, ip);
if(arpenter(er->f, V4, e->spa, e->sha, sizeof(e->sha), e->tpa, ifc, !forme) < 0 || !forme)
break;
n = sizeof(Etherarp);
if(n < ifc->mintu)
n = ifc->mintu;
rbp = allocb(n);
r = (Etherarp*)rbp->rp;
memset(r, 0, sizeof(Etherarp));
hnputs(r->type, ETARP);
hnputs(r->hrd, 1);
hnputs(r->pro, ETIP4);
r->hln = sizeof(r->sha);
r->pln = sizeof(r->spa);
hnputs(r->op, ARPREPLY);
memmove(r->tha, e->sha, sizeof(r->tha));
memmove(r->tpa, e->spa, sizeof(r->tpa));
memmove(r->sha, ifc->mac, sizeof(r->sha));
memmove(r->spa, e->tpa, sizeof(r->spa));
memmove(r->d, e->sha, sizeof(r->d));
memmove(r->s, ifc->mac, sizeof(r->s));
rbp->wp += n;
runlock(ifc);
freeb(ebp);
devtab[er->achan->type]->bwrite(er->achan, rbp, 0);
return;
}
runlock(ifc);
freeb(ebp);
}
static void
recvarpproc(void *v)
{
Ipifc *ifc = v;
Etherrock *er = ifc->arg;
er->arpp = up;
if(waserror()){
er->arpp = nil;
pexit("hangup", 1);
}
for(;;)
recvarp(ifc);
}
static int
multicastea(uchar *ea, uchar *ip)
{
int x;
switch(x = ipismulticast(ip)){
case V4:
ea[0] = 0x01;
ea[1] = 0x00;
ea[2] = 0x5e;
ea[3] = ip[13] & 0x7f;
ea[4] = ip[14];
ea[5] = ip[15];
break;
case V6:
ea[0] = 0x33;
ea[1] = 0x33;
ea[2] = ip[12];
ea[3] = ip[13];
ea[4] = ip[14];
ea[5] = ip[15];
break;
}
return x;
}
/*
* fill in an arp entry for broadcast or multicast
* addresses. Return the first queued packet for the
* IP address.
*/
static Block*
multicastarp(Fs *f, Arpent *a, Medium *medium, uchar *mac)
{
/* is it broadcast? */
if(ipforme(f, a->ip) == Rbcast){
memset(mac, 0xff, medium->maclen);
return arpresolve(f->arp, a, medium, mac);
}
/* if multicast, fill in mac */
switch(multicastea(mac, a->ip)){
case V4:
case V6:
return arpresolve(f->arp, a, medium, mac);
}
/* let arp take care of it */
return nil;
}
void
ethermediumlink(void)
{
addipmedium(ðermedium);
addipmedium(&gbemedium);
}
static void
etherpref2addr(uchar *pref, uchar *ea)
{
pref[8] = ea[0] ^ 0x2;
pref[9] = ea[1];
pref[10] = ea[2];
pref[11] = 0xFF;
pref[12] = 0xFE;
pref[13] = ea[3];
pref[14] = ea[4];
pref[15] = ea[5];
}
static void
etherareg(Fs *f, Ipifc *ifc, Iplifc *lifc, uchar *ip)
{
static char tdad[] = "dad6";
uchar a[IPaddrlen];
if(ipcmp(ip, IPnoaddr) == 0 || ipcmp(ip, v4prefix) == 0)
return;
if(isv4(ip)){
sendgarp(ifc, ip);
return;
}
if((lifc->type&Rv4) != 0)
return;
if(!lifc->tentative){
icmpna(f, lifc->local, v6allnodesL, ip, ifc->mac, 1<<5);
return;
}
if(ipcmp(lifc->local, ip) != 0)
return;
/* temporarily add route for duplicate address detection */
ipv62smcast(a, ip);
addroute(f, a, IPallbits, v6Unspecified, IPallbits, ip, Rmulti, ifc, tdad);
if(waserror()){
remroute(f, a, IPallbits, v6Unspecified, IPallbits, ip, Rmulti, ifc, tdad);
nexterror();
}
icmpns(f, 0, SRC_UNSPEC, ip, TARG_MULTI, ifc->mac);
poperror();
remroute(f, a, IPallbits, v6Unspecified, IPallbits, ip, Rmulti, ifc, tdad);
}