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#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#include "ip.h"
#define DPRINT if(0)print
enum
{
GRE_IPONLY = 12, /* size of ip header */
GRE_IPPLUSGRE = 12, /* minimum size of GRE header */
IP_GREPROTO = 47,
GRErxms = 200,
GREtickms = 100,
GREmaxxmit = 10,
};
typedef struct GREhdr
{
/* ip header */
uchar vihl; /* Version and header length */
uchar tos; /* Type of service */
uchar len[2]; /* packet length (including headers) */
uchar id[2]; /* Identification */
uchar frag[2]; /* Fragment information */
uchar Unused;
uchar proto; /* Protocol */
uchar cksum[2]; /* checksum */
uchar src[4]; /* Ip source */
uchar dst[4]; /* Ip destination */
/* gre header */
uchar flags[2];
uchar eproto[2]; /* encapsulation protocol */
} GREhdr;
typedef struct GREpriv GREpriv;
struct GREpriv
{
int raw; /* Raw GRE mode */
/* non-MIB stats */
ulong csumerr; /* checksum errors */
ulong lenerr; /* short packet */
};
static void grekick(void *x, Block *bp);
static char*
greconnect(Conv *c, char **argv, int argc)
{
Proto *p;
char *err;
Conv *tc, **cp, **ecp;
err = Fsstdconnect(c, argv, argc);
if(err != nil)
return err;
/* make sure noone's already connected to this other sys */
p = c->p;
qlock(p);
ecp = &p->conv[p->nc];
for(cp = p->conv; cp < ecp; cp++){
tc = *cp;
if(tc == nil)
break;
if(tc == c)
continue;
if(tc->rport == c->rport && ipcmp(tc->raddr, c->raddr) == 0){
err = "already connected to that addr/proto";
ipmove(c->laddr, IPnoaddr);
ipmove(c->raddr, IPnoaddr);
break;
}
}
qunlock(p);
if(err != nil)
return err;
Fsconnected(c, nil);
return nil;
}
static void
grecreate(Conv *c)
{
c->rq = qopen(64*1024, Qmsg, 0, c);
c->wq = qbypass(grekick, c);
}
static int
grestate(Conv *c, char *state, int n)
{
USED(c);
return snprint(state, n, "%s", "Datagram");
}
static char*
greannounce(Conv*, char**, int)
{
return "pktifc does not support announce";
}
static void
greclose(Conv *c)
{
qclose(c->rq);
qclose(c->wq);
qclose(c->eq);
ipmove(c->laddr, IPnoaddr);
ipmove(c->raddr, IPnoaddr);
c->lport = 0;
c->rport = 0;
}
int drop;
static void
grekick(void *x, Block *bp)
{
Conv *c = x;
GREhdr *ghp;
uchar laddr[IPaddrlen], raddr[IPaddrlen];
if(bp == nil)
return;
/* Make space to fit ip header (gre header already there) */
bp = padblock(bp, GRE_IPONLY);
if(bp == nil)
return;
/* make sure the message has a GRE header */
bp = pullupblock(bp, GRE_IPONLY+GRE_IPPLUSGRE);
if(bp == nil)
return;
ghp = (GREhdr *)(bp->rp);
ghp->vihl = IP_VER4;
if(!((GREpriv*)c->p->priv)->raw){
v4tov6(raddr, ghp->dst);
if(ipcmp(raddr, v4prefix) == 0)
memmove(ghp->dst, c->raddr + IPv4off, IPv4addrlen);
v4tov6(laddr, ghp->src);
if(ipcmp(laddr, v4prefix) == 0){
if(ipcmp(c->laddr, IPnoaddr) == 0)
findlocalip(c->p->f, c->laddr, raddr); /* pick interface closest to dest */
memmove(ghp->src, c->laddr + IPv4off, IPv4addrlen);
}
hnputs(ghp->eproto, c->rport);
}
ghp->proto = IP_GREPROTO;
ghp->frag[0] = 0;
ghp->frag[1] = 0;
ipoput4(c->p->f, bp, 0, c->ttl, c->tos, nil);
}
static void
greiput(Proto *gre, Ipifc*, Block *bp)
{
int len;
GREhdr *ghp;
Conv *c, **p;
ushort eproto;
uchar raddr[IPaddrlen];
GREpriv *gpriv;
gpriv = gre->priv;
ghp = (GREhdr*)(bp->rp);
v4tov6(raddr, ghp->src);
eproto = nhgets(ghp->eproto);
qlock(gre);
/* Look for a conversation structure for this port and address */
c = nil;
for(p = gre->conv; *p; p++) {
c = *p;
if(c->inuse == 0)
continue;
if(c->rport == eproto &&
(gpriv->raw || ipcmp(c->raddr, raddr) == 0))
break;
}
if(*p == nil) {
qunlock(gre);
freeblist(bp);
return;
}
qunlock(gre);
/*
* Trim the packet down to data size
*/
len = nhgets(ghp->len) - GRE_IPONLY;
if(len < GRE_IPPLUSGRE){
freeblist(bp);
return;
}
bp = trimblock(bp, GRE_IPONLY, len);
if(bp == nil){
gpriv->lenerr++;
return;
}
/*
* Can't delimit packet so pull it all into one block.
*/
if(qlen(c->rq) > 64*1024)
freeblist(bp);
else{
bp = concatblock(bp);
if(bp == 0)
panic("greiput");
qpass(c->rq, bp);
}
}
int
grestats(Proto *gre, char *buf, int len)
{
GREpriv *gpriv;
gpriv = gre->priv;
return snprint(buf, len, "gre: len %lud\n", gpriv->lenerr);
}
char*
grectl(Conv *c, char **f, int n)
{
GREpriv *gpriv;
gpriv = c->p->priv;
if(n == 1){
if(strcmp(f[0], "raw") == 0){
gpriv->raw = 1;
return nil;
}
else if(strcmp(f[0], "cooked") == 0){
gpriv->raw = 0;
return nil;
}
}
return "unknown control request";
}
void
greinit(Fs *fs)
{
Proto *gre;
gre = smalloc(sizeof(Proto));
gre->priv = smalloc(sizeof(GREpriv));
gre->name = "gre";
gre->connect = greconnect;
gre->announce = greannounce;
gre->state = grestate;
gre->create = grecreate;
gre->close = greclose;
gre->rcv = greiput;
gre->ctl = grectl;
gre->advise = nil;
gre->stats = grestats;
gre->ipproto = IP_GREPROTO;
gre->nc = 64;
gre->ptclsize = 0;
Fsproto(fs, gre);
}
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