ref: 909323e92a4e694bff5908e500d8655ac1bbd932
dir: /sys/src/9/port/devbridge.c/
/*
* IP Ethernet bridge
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../ip/ip.h"
#include "../ip/ipv6.h"
#include "../port/netif.h"
#include "../port/error.h"
typedef struct Bridge Bridge;
typedef struct Port Port;
typedef struct Centry Centry;
typedef struct Tcphdr Tcphdr;
enum {
Qtopdir= 1, /* top level directory */
Qbridgedir, /* bridge* directory */
Qbctl,
Qstats,
Qcache,
Qlog,
Qportdir, /* directory for a protocol */
Qpctl,
Qlocal,
Qstatus,
MaxQ,
Maxbridge= 16,
Maxport= 128, /* power of 2 */
CacheHash= 257, /* prime */
CacheLook= 5, /* how many cache entries to examine */
CacheSize= (CacheHash+CacheLook-1),
CacheTimeout= 5*60, /* timeout for cache entry in seconds */
MaxMTU= IP_MAX, /* allow for jumbo frames and large UDP */
TcpMssMax = 1300, /* max desirable Tcp MSS value */
TunnelMtu = 1400,
};
static Dirtab bridgedirtab[] = {
"ctl", {Qbctl}, 0, 0666,
"stats", {Qstats}, 0, 0444,
"cache", {Qcache}, 0, 0444,
"log", {Qlog}, 0, 0666,
};
static Dirtab portdirtab[] = {
"ctl", {Qpctl}, 0, 0666,
"local", {Qlocal}, 0, 0444,
"status", {Qstatus}, 0, 0444,
};
enum {
Logcache= (1<<0),
Logmcast= (1<<1),
};
static Logflag logflags[] = {
{ "cache", Logcache, },
{ "multicast", Logmcast, },
{ nil, 0, },
};
enum {
Tether,
Ttun,
};
static char *typstr[] = {
"ether",
"tunnel",
};
static Dirtab *dirtab[MaxQ];
Dev bridgedevtab;
#define TYPE(x) (((ulong)(x).path) & 0xff)
#define PORT(x) ((((ulong)(x).path) >> 8)&(Maxport-1))
#define QID(x, y) (((x)<<8) | (y))
#define VID(tag) ((tag) & 0xFFF)
struct Centry
{
ushort vid;
uchar d[Eaddrlen];
int portid;
long expire; /* entry expires this many seconds after bootime */
long src;
long dst;
};
struct Bridge
{
RWlock;
ulong dev; /* bridgetab[dev] */
ulong hit;
ulong miss;
ulong drop;
ulong copy;
long delay0; /* constant microsecond delay per packet */
long delayn; /* microsecond delay per byte */
int tcpmss; /* modify tcpmss value */
int nport;
Port *port[Maxport];
Centry cache[CacheSize];
Log;
};
struct Port
{
int id; /* bridge->port[id] */
Bridge *bridge;
Chan *data[2]; /* channel to data */
Proc *readp; /* read proc */
/* the following uniquely identifies the port */
int type;
char name[KNAMELEN];
/* owner hash - avoids bind/unbind races */
ulong ownhash;
/* various stats */
ulong in; /* number of packets read */
ulong inmulti; /* multicast or broadcast */
ulong inunknown; /* unknown address */
ulong out; /* number of packets read */
ulong outmulti; /* multicast or broadcast */
ulong outunknown; /* unknown address */
ulong outfrag; /* fragmented the packet */
/* 802.1q vlan configuration */
ushort pvid;
ushort prio;
uchar member[0x1000/8];
};
enum {
EOLOPT = 0,
NOOPOPT = 1,
MSSOPT = 2,
MSS_LENGTH = 4, /* Mean segment size */
SYN = 0x02, /* Pkt. is synchronise */
TCPHDR = 20,
};
struct Tcphdr
{
uchar sport[2];
uchar dport[2];
uchar seq[4];
uchar ack[4];
uchar flag[2];
uchar win[2];
uchar cksum[2];
uchar urg[2];
};
static Bridge *bridgetab[Maxbridge];
static int bridgegen(Chan *c, char*, Dirtab*, int, int s, Dir *dp);
static void portbind(Bridge *b, int argc, char *argv[]);
static void portunbind(Bridge *b, int argc, char *argv[]);
static void portvlan(Bridge *b, int argc, char *argv[]);
static void etherread(void *a);
static char *cachedump(Bridge *b);
static void cacheflushport(Bridge *b, int portid);
static void etherwrite(Port *port, Block *bp, ushort tag);
static void
clearmember(Port *port)
{
memset(port->member, 0, sizeof(port->member));
}
static void
addmember(Port *port, ushort vid)
{
/* vlan ids 0 and 4095 are reserved */
if(vid == 0 || vid >= 0xFFF)
return;
port->member[vid/8] |= 1 << (vid % 8);
}
static int
ismember(Port *port, ushort vid)
{
return port->member[vid/8] & (1 << (vid%8));
}
static Block*
tagpkt(Block *bp, ushort tag)
{
uchar *h;
bp = padblock(bp, 4);
memmove(bp->rp, bp->rp+4, 2*Eaddrlen);
h = bp->rp + 2*Eaddrlen;
h[0] = 0x81;
h[1] = 0x00;
h[2] = tag>>8;
h[3] = tag;
return bp;
}
static ushort
untagpkt(Block *bp)
{
uchar *h = bp->rp + 2*Eaddrlen;
ushort tag = h[2]<<8 | h[3];
memmove(bp->rp+4, bp->rp, 2*Eaddrlen);
bp->rp += 4;
return tag;
}
static void
bridgeinit(void)
{
int i;
Dirtab *dt;
/* setup dirtab with non directory entries */
for(i=0; i<nelem(bridgedirtab); i++) {
dt = bridgedirtab + i;
dirtab[TYPE(dt->qid)] = dt;
}
for(i=0; i<nelem(portdirtab); i++) {
dt = portdirtab + i;
dirtab[TYPE(dt->qid)] = dt;
}
}
static Chan*
bridgeattach(char *spec)
{
Chan *c;
ulong dev;
dev = strtoul(spec, nil, 10);
if(dev >= Maxbridge)
error(Enodev);
if(bridgetab[dev] == nil){
static Lock lk;
Bridge *b;
/* only hostowner should create new bridges */
if(!iseve())
error(Enoattach);
b = malloc(sizeof(Bridge));
if(b == nil)
error(Enomem);
b->dev = dev;
lock(&lk);
if(bridgetab[dev] == nil){
bridgetab[dev] = b;
unlock(&lk);
} else {
unlock(&lk);
free(b);
}
}
c = devattach(bridgedevtab.dc, spec);
mkqid(&c->qid, QID(0, Qtopdir), 0, QTDIR);
c->dev = dev;
return c;
}
static Walkqid*
bridgewalk(Chan *c, Chan *nc, char **name, int nname)
{
return devwalk(c, nc, name, nname, (Dirtab*)0, 0, bridgegen);
}
static int
bridgestat(Chan* c, uchar* db, int n)
{
return devstat(c, db, n, (Dirtab *)0, 0L, bridgegen);
}
static Chan*
bridgeopen(Chan* c, int omode)
{
Bridge *b = bridgetab[c->dev];
switch(TYPE(c->qid)) {
default:
break;
case Qlog:
logopen(b);
break;
case Qcache:
rlock(b);
c->aux = cachedump(b);
runlock(b);
if(c->aux == nil)
error(Enomem);
break;
}
c->mode = openmode(omode);
c->flag |= COPEN;
c->offset = 0;
return c;
}
static void
bridgeclose(Chan* c)
{
Bridge *b = bridgetab[c->dev];
switch(TYPE(c->qid)) {
case Qcache:
if(c->flag & COPEN)
free(c->aux);
break;
case Qlog:
if(c->flag & COPEN)
logclose(b);
break;
}
}
static int
getvlancfg(Port *port, char *buf, int nbuf)
{
char *s = buf, *e = buf + nbuf;
int i, j;
s = seprint(s, e, "%ud", port->pvid);
if(port->prio)
s = seprint(s, e, "#%ud", port->prio>>12);
i = 0;
for(j = 1; j <= 0xFFF; j++){
if(ismember(port, j)){
if(i == 0)
i = j;
continue;
} else if(i == 0)
continue;
if(i == j-1)
s = seprint(s, e, ",%d", i);
else
s = seprint(s, e, ",%d-%d", i, j-1);
i = 0;
}
return s - buf;
}
static long
bridgeread(Chan *c, void *a, long n, vlong off)
{
Bridge *b = bridgetab[c->dev];
char buf[512];
Port *port;
int i;
ulong ingood, outgood;
switch(TYPE(c->qid)) {
default:
error(Egreg);
case Qtopdir:
case Qbridgedir:
case Qportdir:
return devdirread(c, a, n, 0, 0, bridgegen);
case Qlog:
return logread(b, a, off, n);
case Qlocal:
return 0; /* TO DO */
case Qstatus:
rlock(b);
if(waserror()){
runlock(b);
nexterror();
}
port = b->port[PORT(c->qid)];
if(port == nil)
strcpy(buf, "unbound\n");
else {
i = 0;
i += snprint(buf+i, sizeof(buf)-i, "%s %s: ", typstr[port->type], port->name);
i += snprint(buf+i, sizeof(buf)-i, "vlan=");
i += getvlancfg(port, buf+i, sizeof(buf)-i);
i += snprint(buf+i, sizeof(buf)-i, " ");
ingood = port->in - port->inmulti - port->inunknown;
outgood = port->out - port->outmulti - port->outunknown;
i += snprint(buf+i, sizeof(buf)-i,
"in=%lud(%lud:%lud:%lud) out=%lud(%lud:%lud:%lud:%lud)\n",
port->in, ingood, port->inmulti, port->inunknown,
port->out, outgood, port->outmulti,
port->outunknown, port->outfrag);
USED(i);
}
poperror();
runlock(b);
return readstr(off, a, n, buf);
case Qbctl:
snprint(buf, sizeof(buf), "%s tcpmss\ndelay %ld %ld\n",
b->tcpmss ? "set" : "clear", b->delay0, b->delayn);
n = readstr(off, a, n, buf);
return n;
case Qcache:
n = readstr(off, a, n, c->aux);
return n;
case Qstats:
snprint(buf, sizeof(buf), "hit=%uld miss=%uld drop=%uld copy=%uld\n",
b->hit, b->miss, b->drop, b->copy);
n = readstr(off, a, n, buf);
return n;
}
}
static void
bridgeoption(Bridge *b, char *option, int value)
{
if(strcmp(option, "tcpmss") == 0)
b->tcpmss = value;
else
error("unknown bridge option");
}
static long
bridgewrite(Chan *c, void *a, long n, vlong off)
{
Bridge *b = bridgetab[c->dev];
Cmdbuf *cb;
char *arg0, *p;
USED(off);
switch(TYPE(c->qid)) {
default:
error(Eperm);
case Qbctl:
cb = parsecmd(a, n);
if(waserror()){
free(cb);
nexterror();
}
if(cb->nf == 0)
error("short write");
arg0 = cb->f[0];
if(strcmp(arg0, "bind") == 0)
portbind(b, cb->nf-1, cb->f+1);
else {
wlock(b);
if(waserror()) {
wunlock(b);
nexterror();
}
if(strcmp(arg0, "unbind") == 0) {
portunbind(b, cb->nf-1, cb->f+1);
} else if(strcmp(arg0, "vlan") == 0) {
portvlan(b, cb->nf-1, cb->f+1);
} else if(strcmp(arg0, "cacheflush") == 0) {
cacheflushport(b, -1);
} else if(strcmp(arg0, "set") == 0) {
if(cb->nf != 2)
error("usage: set option");
bridgeoption(b, cb->f[1], 1);
} else if(strcmp(arg0, "clear") == 0) {
if(cb->nf != 2)
error("usage: clear option");
bridgeoption(b, cb->f[1], 0);
} else if(strcmp(arg0, "delay") == 0) {
if(cb->nf != 3)
error("usage: delay delay0 delayn");
b->delay0 = strtol(cb->f[1], nil, 10);
b->delayn = strtol(cb->f[2], nil, 10);
} else
error("unknown control request");
wunlock(b);
poperror();
}
free(cb);
poperror();
return n;
case Qlog:
cb = parsecmd(a, n);
p = logctl(b, cb->nf, cb->f, logflags);
free(cb);
if(p != nil)
error(p);
return n;
}
}
static int
bridgegen(Chan *c, char *, Dirtab*, int, int s, Dir *dp)
{
Bridge *b = bridgetab[c->dev];
int type = TYPE(c->qid);
Dirtab *dt;
Qid qid;
if(s == DEVDOTDOT){
switch(TYPE(c->qid)){
case Qtopdir:
case Qbridgedir:
snprint(up->genbuf, sizeof(up->genbuf), "#%C%lud", bridgedevtab.dc, c->dev);
mkqid(&qid, Qtopdir, 0, QTDIR);
devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
break;
case Qportdir:
snprint(up->genbuf, sizeof(up->genbuf), "bridge%lud", c->dev);
mkqid(&qid, Qbridgedir, 0, QTDIR);
devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
break;
default:
panic("bridgewalk %llux", c->qid.path);
}
return 1;
}
switch(type) {
default:
/* non-directory entries end up here */
if(c->qid.type & QTDIR)
panic("bridgegen: unexpected directory");
if(s != 0)
return -1;
dt = dirtab[TYPE(c->qid)];
if(dt == nil)
panic("bridgegen: unknown type: %lud", TYPE(c->qid));
devdir(c, c->qid, dt->name, dt->length, eve, dt->perm, dp);
return 1;
case Qtopdir:
if(s != 0)
return -1;
snprint(up->genbuf, sizeof(up->genbuf), "bridge%lud", c->dev);
mkqid(&qid, QID(0, Qbridgedir), 0, QTDIR);
devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
return 1;
case Qbridgedir:
if(s<nelem(bridgedirtab)) {
dt = bridgedirtab+s;
devdir(c, dt->qid, dt->name, dt->length, eve, dt->perm, dp);
return 1;
}
s -= nelem(bridgedirtab);
if(s >= b->nport)
return -1;
mkqid(&qid, QID(s, Qportdir), 0, QTDIR);
snprint(up->genbuf, sizeof(up->genbuf), "%d", s);
devdir(c, qid, up->genbuf, 0, eve, 0555, dp);
return 1;
case Qportdir:
if(s>=nelem(portdirtab))
return -1;
dt = portdirtab+s;
mkqid(&qid, QID(PORT(c->qid),TYPE(dt->qid)), 0, QTFILE);
devdir(c, qid, dt->name, dt->length, eve, dt->perm, dp);
return 1;
}
}
static char*
vlanrange(char *s, int *i, int *j)
{
char *x;
*j = -1;
*i = strtol(s, &x, 10);
if(x <= s)
return x;
if(*i < 0) {
/* -nnn */
*j = -(*i);
*i = 1;
} else if(*x == '-') {
/* nnn- */
s = x;
*j = -strtol(s, &x, 10);
if(x <= s || *j <= 0)
*j = 0xFFE;
} else {
/* nnn */
*j = *i;
}
return x;
}
/*
* set the vlan configuration of a port.
* first number is the pvid (port vlan id)
* followed by zero or more other vlan members.
* members can be specified as comma separated ranges:
* -10,13,50-60,1000- => [1..10],13,[50-60],[1000-4094]
*/
static void
setvlancfg(Port *port, char *cfg)
{
int i, j;
clearmember(port);
port->pvid = strtol(cfg, &cfg, 10);
if(port->pvid >= 0xFFF)
port->pvid = 0;
if(*cfg == '#'){
cfg++;
port->prio = strtoul(cfg, &cfg, 10)<<12;
} else {
port->prio = 0<<12;
}
while(*cfg == ','){
cfg = vlanrange(++cfg, &i, &j);
for(; i <= j; i++)
addmember(port, i);
}
addmember(port, port->pvid);
}
static void
portfree(Port *port)
{
if(port->data[0])
cclose(port->data[0]);
if(port->data[1])
cclose(port->data[1]);
free(port);
}
static void
portbind(Bridge *b, int argc, char *argv[])
{
Port *port;
Chan *ctl;
int type, i, n;
ulong ownhash;
char *dev, *dev2, *vlan;
char buf[100], name[KNAMELEN], path[8*KNAMELEN];
static char usage[] = "usage: bind type name ownhash dev [dev2] [pvid[,vlans...]]";
dev2 = nil;
vlan = "1"; /* default vlan configuration */
if(argc < 4)
error(usage);
for(type = 0; type < nelem(typstr); type++)
if(strcmp(argv[0], typstr[type]) == 0)
break;
memset(name, 0, KNAMELEN);
strncpy(name, argv[1], KNAMELEN);
name[KNAMELEN-1] = 0;
ownhash = strtoul(argv[2], nil, 10);
dev = argv[3];
switch(type){
default:
error(usage);
case Tether:
if(argc > 4)
vlan = argv[4];
break;
case Ttun:
if(argc < 5)
error(usage);
if(argc > 5)
vlan = argv[5];
dev2 = argv[4];
break;
}
port = malloc(sizeof(Port));
if(port == nil)
error(Enomem);
port->id = -1;
port->type = type;
memmove(port->name, name, KNAMELEN);
port->ownhash = ownhash;
port->readp = (void*)-1;
port->data[0] = nil;
port->data[1] = nil;
if(waserror()) {
portfree(port);
nexterror();
}
setvlancfg(port, vlan);
switch(port->type) {
default:
panic("portbind: unknown port type: %d", type);
case Tether:
snprint(path, sizeof(path), "%s/clone", dev);
ctl = namec(path, Aopen, ORDWR, 0);
if(waserror()) {
cclose(ctl);
nexterror();
}
/* get directory name */
n = devtab[ctl->type]->read(ctl, buf, sizeof(buf)-1, 0);
buf[n] = 0;
snprint(path, sizeof(path), "%s/%lud/data", dev, strtoul(buf, 0, 0));
/* setup connection to be promiscuous */
snprint(buf, sizeof(buf), "connect -1");
devtab[ctl->type]->write(ctl, buf, strlen(buf), 0);
snprint(buf, sizeof(buf), "nonblocking");
devtab[ctl->type]->write(ctl, buf, strlen(buf), 0);
snprint(buf, sizeof(buf), "promiscuous");
devtab[ctl->type]->write(ctl, buf, strlen(buf), 0);
snprint(buf, sizeof(buf), "bridge");
devtab[ctl->type]->write(ctl, buf, strlen(buf), 0);
/* open data port */
port->data[0] = namec(path, Aopen, ORDWR, 0);
incref(port->data[0]);
port->data[1] = port->data[0];
poperror();
cclose(ctl);
break;
case Ttun:
port->data[0] = namec(dev, Aopen, OREAD, 0);
port->data[1] = namec(dev2, Aopen, OWRITE, 0);
break;
}
/* try to insert port into the bridge */
wlock(b);
if(waserror()){
wunlock(b);
nexterror();
}
for(i=0; i<b->nport; i++) {
if(b->port[i] == nil)
continue;
if(b->port[i]->type == type && memcmp(b->port[i]->name, name, KNAMELEN) == 0)
error("port in use");
}
for(i=0; i<Maxport; i++)
if(b->port[i] == nil)
break;
if(i >= Maxport)
error("no more ports");
/* committed to binding port */
poperror();
poperror();
port->id = i;
port->bridge = b;
b->port[i] = port;
if(i >= b->nport)
b->nport = i+1;
wunlock(b);
/* start the reader */
snprint(buf, sizeof(buf), "#%C%lud/bridge%lud/%d:%s",
bridgedevtab.dc, b->dev, b->dev, i, dev);
kproc(buf, etherread, port);
}
static Port*
getport(Bridge *b, int argc, char **argv)
{
static char usage[] = "usage: ... type name [ownhash]";
int type, i;
char name[KNAMELEN];
ulong ownhash;
Port *port;
if(argc < 2)
error(usage);
for(type = 0; type < nelem(typstr); type++)
if(strcmp(argv[0], typstr[type]) == 0)
break;
if(type >= nelem(typstr))
error(usage);
memset(name, 0, KNAMELEN);
strncpy(name, argv[1], KNAMELEN);
name[KNAMELEN-1] = 0;
if(argc == 3)
ownhash = strtoul(argv[2], nil, 10);
else
ownhash = 0;
port = nil;
for(i=0; i<b->nport; i++) {
port = b->port[i];
if(port != nil && port->type == type
&& memcmp(port->name, name, KNAMELEN) == 0)
break;
}
if(i >= b->nport)
error("port not found");
if(ownhash != 0 && port->ownhash != 0 && ownhash != port->ownhash)
error("bad owner hash");
return port;
}
static void
unbindport(Bridge *b, Port *port)
{
if(port->bridge != b)
return;
port->bridge = nil;
b->port[port->id] = nil;
cacheflushport(b, port->id);
}
static void
portunbind(Bridge *b, int argc, char *argv[])
{
Port *port = getport(b, argc, argv);
/* wait for reader to startup */
while(port->readp == (void*)-1)
tsleep(&up->sleep, return0, 0, 300);
/* stop reader */
postnote(port->readp, 1, "unbind", 0);
unbindport(b, port);
}
static void
portvlan(Bridge *b, int argc, char *argv[])
{
Port *port = getport(b, argc-1, argv+1);
cacheflushport(b, port->id);
setvlancfg(port, argv[0]);
}
static Centry *
cacheent(Bridge *b, uchar d[Eaddrlen], ushort vid)
{
uint h = (uint)vid*587;
int i;
for(i=0; i<Eaddrlen; i++) {
h *= 7;
h += d[i];
}
return &b->cache[h % CacheHash];
}
static Centry *
cachelookup(Bridge *b, uchar d[Eaddrlen], ushort vid)
{
Centry *p, *e;
long sec;
for(p = cacheent(b, d, vid), e = p+CacheLook; p < e; p++) {
if(p->vid == vid && memcmp(d, p->d, Eaddrlen) == 0) {
sec = TK2SEC(MACHP(0)->ticks);
if(sec >= p->expire)
break;
p->expire = sec + CacheTimeout;
return p;
}
}
return nil;
}
static void
cacheenter(Bridge *b, uchar d[Eaddrlen], int portid, ushort vid)
{
Centry *p, *e, *pp;
long sec;
pp = cacheent(b, d, vid);
sec = pp->expire;
for(p = pp, e = pp+CacheLook; p < e; p++) {
if(p->vid == vid && memcmp(d, p->d, Eaddrlen) == 0){
if(p->portid != portid)
log(b, Logcache, "NIC changed port: %E %ud %d->%d\n",
d, vid, p->portid, portid);
pp = p;
goto Update;
}
if(p->expire < sec){
pp = p;
sec = p->expire;
}
}
if(pp->expire != 0)
log(b, Logcache, "bumping from cache: %E %ud %d\n", pp->d, pp->vid, pp->portid);
Update:
log(b, Logcache, "adding to cache: %E %ud %d\n", d, vid, portid);
sec = TK2SEC(MACHP(0)->ticks);
pp->expire = sec + CacheTimeout;
pp->vid = vid;
pp->portid = portid;
pp->src = 1;
pp->dst = 0;
memmove(pp->d, d, Eaddrlen);
}
static void
cacheflushport(Bridge *b, int portid)
{
Centry *p, *e;
log(b, Logcache, "cache flush: %d\n", portid);
e = &b->cache[CacheSize];
for(p = b->cache; p < e; p++){
if(p->expire == 0)
continue;
if(portid < 0 || p->portid == portid){
log(b, Logcache, "deleting from cache: %E %ud %d\n", p->d, p->vid, p->portid);
memset(p, 0, sizeof(Centry));
}
}
}
static char *
cachedump(Bridge *b)
{
long off, sec, n;
char *buf, *p, *ep;
Centry *c, *e;
e = &b->cache[CacheSize];
n = 0;
for(c = b->cache; c < e; c++)
if(c->expire != 0)
n++;
n *= 13+5+3+11+11+11+2;
buf = malloc(++n);
if(buf == nil)
return nil;
p = buf;
ep = buf + n;
sec = TK2SEC(MACHP(0)->ticks);
off = seconds() - sec;
for(c = b->cache; c < e; c++){
if(c->expire == 0)
continue;
p = seprint(p, ep, "%E %4ud %2d %10ld %10ld %10ld %c\n",
c->d, c->vid, c->portid,
c->src, c->dst, c->expire+off,
(sec < c->expire)?'v':'e');
}
*p = '\0';
return buf;
}
static void
ethermultiwrite(Bridge *b, Block *bp, int portid, ushort tag)
{
Port *oport;
Etherpkt *ep;
int i, mcast;
ushort vid;
vid = VID(tag);
ep = (Etherpkt*)bp->rp;
mcast = ep->d[0] & 1; /* multicast bit of ethernet address */
oport = nil;
for(i=0; i<b->nport; i++) {
if(i == portid || b->port[i] == nil || !ismember(b->port[i], vid))
continue;
/*
* we need to forward multicast packets for ipv6,
* so always do it.
*/
if(mcast)
b->port[i]->outmulti++;
else
b->port[i]->outunknown++;
/* delay one so that the last write does not copy */
if(oport != nil) {
b->copy++;
etherwrite(oport, copyblock(bp, BLEN(bp)), tag);
}
oport = b->port[i];
}
/* last write free block */
if(oport)
etherwrite(oport, bp, tag);
else
freeb(bp);
}
static void
tcpmsshack(Etherpkt *epkt, int n)
{
int hl, optlen;
Tcphdr *tcphdr;
ulong mss, cksum;
uchar *optr;
/* ignore non-ip packets */
switch(nhgets(epkt->type)){
case ETIP4:
case ETIP6:
break;
default:
return;
}
n -= ETHERHDRSIZE;
if(n < 1)
return;
switch(epkt->data[0]&0xF0){
case IP_VER4:
hl = (epkt->data[0]&15)<<2;
if(n < hl+TCPHDR || hl < IP4HDR || epkt->data[9] != TCP)
return;
n -= hl;
tcphdr = (Tcphdr*)(epkt->data + hl);
break;
case IP_VER6:
if(n < IP6HDR+TCPHDR || epkt->data[6] != TCP)
return;
n -= IP6HDR;
tcphdr = (Tcphdr*)(epkt->data + IP6HDR);
break;
default:
return;
}
/* MSS can only appear in SYN packet */
if(!(tcphdr->flag[1] & SYN))
return;
hl = (tcphdr->flag[0] & 0xf0)>>2;
if(n < hl)
return;
/* check for MSS option */
optr = (uchar*)tcphdr + TCPHDR;
n = hl - TCPHDR;
for(;;) {
if(n <= 0 || *optr == EOLOPT)
return;
if(*optr == NOOPOPT) {
n--;
optr++;
continue;
}
optlen = optr[1];
if(optlen < 2 || optlen > n)
return;
if(*optr == MSSOPT && optlen == MSS_LENGTH)
break;
n -= optlen;
optr += optlen;
}
mss = nhgets(optr+2);
if(mss <= TcpMssMax)
return;
/* fix checksum */
cksum = nhgets(tcphdr->cksum);
if(optr-(uchar*)tcphdr & 1) {
// odd alignments are a pain
cksum += nhgets(optr+1);
cksum -= (optr[1]<<8)|(TcpMssMax>>8);
cksum += (cksum>>16);
cksum &= 0xffff;
cksum += nhgets(optr+3);
cksum -= ((TcpMssMax&0xff)<<8)|optr[4];
cksum += (cksum>>16);
} else {
cksum += mss;
cksum -= TcpMssMax;
cksum += (cksum>>16);
}
hnputs(tcphdr->cksum, cksum);
hnputs(optr+2, TcpMssMax);
}
/*
* process to read from the ethernet
*/
static void
etherread(void *a)
{
Port *port = a;
Bridge *b = port->bridge;
Block *bp;
Etherpkt *ep;
Centry *ce;
long n;
ushort type, tag;
port->readp = up;
if(waserror()) {
print("%s: %s\n", up->text, up->errstr);
goto Exit;
}
while(port->bridge == b) {
bp = devtab[port->data[0]->type]->bread(port->data[0], MaxMTU, 0);
if(bp == nil)
break;
n = BLEN(bp);
/* delay packets to simulate a slow link */
if(b->delay0 != 0 || b->delayn != 0){
long md = b->delay0 + b->delayn * n;
if(md > 0)
microdelay(md);
}
rlock(b);
if(port->bridge != b)
goto Drop;
port->in++;
/* short packet? */
if(n < ETHERHDRSIZE)
goto Drop;
/* untag vlan packets */
ep = (Etherpkt*)bp->rp;
type = ep->type[0]<<8|ep->type[1];
if(type != 0x8100) {
/* untagged packet is native vlan */
tag = port->pvid;
if(tag == 0)
goto Drop;
tag |= port->prio;
} else {
/* short packet? */
n -= 4;
if(n < ETHERHDRSIZE)
goto Drop;
tag = untagpkt(bp);
if(!ismember(port, VID(tag))) {
/* wrong vlan id? */
if(VID(tag) != 0 || port->pvid == 0)
goto Drop;
/* priority tagged packet on native vlan */
tag |= port->pvid;
}
ep = (Etherpkt*)bp->rp;
type = ep->type[0]<<8|ep->type[1];
}
if(b->tcpmss)
tcpmsshack(ep, n);
/* learn source MAC addresses */
if((ep->s[0] & 1) == 0) {
ce = cachelookup(b, ep->s, VID(tag));
if(ce != nil && ce->portid == port->id)
ce->src++;
else {
runlock(b), wlock(b);
if(port->bridge == b)
cacheenter(b, ep->s, port->id, VID(tag));
wunlock(b), rlock(b);
if(port->bridge != b)
goto Drop;
}
}
/* forward to destination port(s) */
if(ep->d[0] & 1) {
port->inmulti++;
log(b, Logmcast, "multicast: port=%d tag=%#.4ux src=%E dst=%E type=%#.4ux\n",
port->id, tag, ep->s, ep->d, type);
ethermultiwrite(b, bp, port->id, tag);
} else {
ce = cachelookup(b, ep->d, VID(tag));
if(ce == nil) {
port->inunknown++;
b->miss++;
ethermultiwrite(b, bp, port->id, tag);
}else if(ce->portid != port->id){
ce->dst++;
b->hit++;
etherwrite(b->port[ce->portid], bp, tag);
} else{
Drop:
b->drop++;
runlock(b);
freeb(bp);
continue;
}
}
runlock(b);
}
Exit:
port->readp = nil;
wlock(b);
unbindport(b, port);
wunlock(b);
print("%s: unbound\n", up->text);
portfree(port);
pexit("hangup", 1);
}
static int
fragment(Etherpkt *epkt, int n)
{
Ip4hdr *iphdr;
if(n <= TunnelMtu)
return 0;
/* ignore non-ipv4 packets */
if(nhgets(epkt->type) != ETIP4)
return 0;
iphdr = (Ip4hdr*)(epkt->data);
n -= ETHERHDRSIZE;
/*
* ignore: IP runt packets, bad packets (I don't handle IP
* options for the moment), packets with don't-fragment set,
* and short blocks.
*/
if(n < IP4HDR || iphdr->vihl != (IP_VER4|IP_HLEN4) ||
iphdr->frag[0] & (IP_DF>>8) || nhgets(iphdr->length) > n)
return 0;
return 1;
}
static void
etherwrite1(Port *port, Block *bp, ushort tag)
{
if(VID(tag) != port->pvid)
bp = tagpkt(bp, tag);
/* don't generate small packets */
if(BLEN(bp) < ETHERMINTU)
bp = adjustblock(bp, ETHERMINTU);
devtab[port->data[1]->type]->bwrite(port->data[1], bp, 0);
}
static void
etherwrite(Port *port, Block *bp, ushort tag)
{
Ip4hdr *eh, *feh;
Etherpkt *epkt;
int lid, len, seglen, dlen, blklen, mf;
Block *nb;
ushort fragoff, frag;
port->out++;
epkt = (Etherpkt*)bp->rp;
if(port->type != Ttun || !fragment(epkt, BLEN(bp))) {
if(!waserror()){
etherwrite1(port, bp, tag);
poperror();
}
return;
}
port->outfrag++;
if(waserror()){
freeb(bp);
return;
}
seglen = (TunnelMtu - ETHERHDRSIZE - IP4HDR) & ~7;
eh = (Ip4hdr*)(epkt->data);
len = nhgets(eh->length);
frag = nhgets(eh->frag);
mf = frag & IP_MF;
frag <<= 3;
dlen = len - IP4HDR;
lid = nhgets(eh->id);
bp->rp += ETHERHDRSIZE+IP4HDR;
for(fragoff = 0; fragoff < dlen; fragoff += seglen) {
nb = allocb(ETHERHDRSIZE+IP4HDR+seglen);
feh = (Ip4hdr*)(nb->wp+ETHERHDRSIZE);
memmove(nb->wp, epkt, ETHERHDRSIZE+IP4HDR);
nb->wp += ETHERHDRSIZE+IP4HDR;
if((fragoff + seglen) >= dlen) {
seglen = dlen - fragoff;
hnputs(feh->frag, (frag+fragoff)>>3 | mf);
}
else
hnputs(feh->frag, (frag+fragoff>>3) | IP_MF);
hnputs(feh->length, seglen + IP4HDR);
hnputs(feh->id, lid);
if(seglen){
blklen = BLEN(bp);
if(seglen < blklen)
blklen = seglen;
memmove(nb->wp, bp->rp, blklen);
nb->wp += blklen;
bp->rp += blklen;
}
feh->cksum[0] = 0;
feh->cksum[1] = 0;
hnputs(feh->cksum, ipcsum(&feh->vihl));
etherwrite1(port, nb, tag);
}
poperror();
freeb(bp);
}
Dev bridgedevtab = {
'B',
"bridge",
devreset,
bridgeinit,
devshutdown,
bridgeattach,
bridgewalk,
bridgestat,
bridgeopen,
devcreate,
bridgeclose,
bridgeread,
devbread,
bridgewrite,
devbwrite,
devremove,
devwstat,
};