ref: a411870ee4640241e3c494367d922847da84f972
dir: purgatorio/os/boot/pc/bootp.c
#include "u.h"
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ip.h"
extern int debugload;
uchar broadcast[Eaddrlen] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
};
static ushort tftpport = 5000;
static int Id = 1;
static Netaddr myaddr;
static Netaddr server;
typedef struct {
uchar header[4];
uchar data[Segsize];
} Tftp;
static Tftp tftpb;
static void
hnputs(uchar *ptr, ushort val)
{
ptr[0] = val>>8;
ptr[1] = val;
}
static void
hnputl(uchar *ptr, ulong val)
{
ptr[0] = val>>24;
ptr[1] = val>>16;
ptr[2] = val>>8;
ptr[3] = val;
}
static ulong
nhgetl(uchar *ptr)
{
return ((ptr[0]<<24) | (ptr[1]<<16) | (ptr[2]<<8) | ptr[3]);
}
static ushort
nhgets(uchar *ptr)
{
return ((ptr[0]<<8) | ptr[1]);
}
static short endian = 1;
static char* aendian = (char*)&endian;
#define LITTLE *aendian
static ushort
ptcl_csum(void *a, int len)
{
uchar *addr;
ulong t1, t2;
ulong losum, hisum, mdsum, x;
addr = a;
losum = 0;
hisum = 0;
mdsum = 0;
x = 0;
if((ulong)addr & 1) {
if(len) {
hisum += addr[0];
len--;
addr++;
}
x = 1;
}
while(len >= 16) {
t1 = *(ushort*)(addr+0);
t2 = *(ushort*)(addr+2); mdsum += t1;
t1 = *(ushort*)(addr+4); mdsum += t2;
t2 = *(ushort*)(addr+6); mdsum += t1;
t1 = *(ushort*)(addr+8); mdsum += t2;
t2 = *(ushort*)(addr+10); mdsum += t1;
t1 = *(ushort*)(addr+12); mdsum += t2;
t2 = *(ushort*)(addr+14); mdsum += t1;
mdsum += t2;
len -= 16;
addr += 16;
}
while(len >= 2) {
mdsum += *(ushort*)addr;
len -= 2;
addr += 2;
}
if(x) {
if(len)
losum += addr[0];
if(LITTLE)
losum += mdsum;
else
hisum += mdsum;
} else {
if(len)
hisum += addr[0];
if(LITTLE)
hisum += mdsum;
else
losum += mdsum;
}
losum += hisum >> 8;
losum += (hisum & 0xff) << 8;
while(hisum = losum>>16)
losum = hisum + (losum & 0xffff);
return ~losum;
}
static ushort
ip_csum(uchar *addr)
{
int len;
ulong sum = 0;
len = (addr[0]&0xf)<<2;
while(len > 0) {
sum += addr[0]<<8 | addr[1] ;
len -= 2;
addr += 2;
}
sum = (sum & 0xffff) + (sum >> 16);
sum = (sum & 0xffff) + (sum >> 16);
return (sum^0xffff);
}
enum {
/* this is only true of IPv4, but we're not doing v6 yet */
Min_udp_payload = ETHERMINTU - ETHERHDRSIZE - UDP_HDRSIZE,
};
static void
udpsend(int ctlrno, Netaddr *a, void *data, int dlen)
{
char payload[ETHERMAXTU];
Udphdr *uh;
Etherhdr *ip;
Etherpkt pkt;
int len, ptcllen;
/*
* if packet is too short, make it longer rather than relying
* on ethernet interface or lower layers to pad it.
*/
if (dlen < Min_udp_payload) {
memmove(payload, data, dlen);
data = payload;
dlen = Min_udp_payload;
}
uh = (Udphdr*)&pkt;
memset(uh, 0, sizeof(Etherpkt));
memmove(uh->udpcksum+sizeof(uh->udpcksum), data, dlen);
/*
* UDP portion
*/
ptcllen = dlen + (UDP_HDRSIZE-UDP_PHDRSIZE);
uh->ttl = 0;
uh->udpproto = IP_UDPPROTO;
uh->frag[0] = 0;
uh->frag[1] = 0;
hnputs(uh->udpplen, ptcllen);
hnputl(uh->udpsrc, myaddr.ip);
hnputs(uh->udpsport, myaddr.port);
hnputl(uh->udpdst, a->ip);
hnputs(uh->udpdport, a->port);
hnputs(uh->udplen, ptcllen);
uh->udpcksum[0] = 0;
uh->udpcksum[1] = 0;
dlen = (dlen+1)&~1;
hnputs(uh->udpcksum, ptcl_csum(&uh->ttl, dlen+UDP_HDRSIZE));
/*
* IP portion
*/
ip = (Etherhdr*)&pkt;
len = UDP_EHSIZE+UDP_HDRSIZE+dlen; /* non-descriptive names */
ip->vihl = IP_VER|IP_HLEN;
ip->tos = 0;
ip->ttl = 255;
hnputs(ip->length, len-ETHER_HDR);
hnputs(ip->id, Id++);
ip->frag[0] = 0;
ip->frag[1] = 0;
ip->cksum[0] = 0;
ip->cksum[1] = 0;
hnputs(ip->cksum, ip_csum(&ip->vihl));
/*
* Ethernet MAC portion
*/
hnputs(ip->type, ET_IP);
memmove(ip->d, a->ea, sizeof(ip->d));
if(debug) {
print("udpsend ");
}
ethertxpkt(ctlrno, &pkt, len, Timeout);
}
static void
nak(int ctlrno, Netaddr *a, int code, char *msg, int report)
{
int n;
char buf[128];
buf[0] = 0;
buf[1] = Tftp_ERROR;
buf[2] = 0;
buf[3] = code;
strcpy(buf+4, msg);
n = strlen(msg) + 4 + 1;
udpsend(ctlrno, a, buf, n);
if(report)
print("\ntftp: error(%d): %s\n", code, msg);
}
static int
udprecv(int ctlrno, Netaddr *a, void *data, int dlen)
{
int n, len;
ushort csm;
Udphdr *h;
ulong addr, timo;
Etherpkt pkt;
static int rxactive;
if(rxactive == 0)
timo = 1000;
else
timo = Timeout;
timo += TK2MS(m->ticks);
while(timo > TK2MS(m->ticks)){
n = etherrxpkt(ctlrno, &pkt, timo-TK2MS(m->ticks));
if(n <= 0)
continue;
h = (Udphdr*)&pkt;
if(debug)
print("udprecv %E to %E...\n", h->s, h->d);
if(nhgets(h->type) != ET_IP) {
if(debug)
print("not ip...");
continue;
}
if(ip_csum(&h->vihl)) {
print("ip chksum error\n");
continue;
}
if(h->vihl != (IP_VER|IP_HLEN)) {
print("ip bad vers/hlen\n");
continue;
}
if(h->udpproto != IP_UDPPROTO) {
if(debug)
print("not udp (%d)...", h->udpproto);
continue;
}
if(debug)
print("okay udp...");
h->ttl = 0;
len = nhgets(h->udplen);
hnputs(h->udpplen, len);
if(nhgets(h->udpcksum)) {
csm = ptcl_csum(&h->ttl, len+UDP_PHDRSIZE);
if(csm != 0) {
print("udp chksum error csum #%4ux len %d\n",
csm, n);
break;
}
}
if(a->port != 0 && nhgets(h->udpsport) != a->port) {
if(debug)
print("udpport %ux not %ux\n",
nhgets(h->udpsport), a->port);
continue;
}
addr = nhgetl(h->udpsrc);
if(a->ip != Bcastip && a->ip != addr) {
if(debug)
print("bad ip %lux not %lux\n", addr, a->ip);
continue;
}
len -= UDP_HDRSIZE-UDP_PHDRSIZE;
if(len > dlen) {
print("udp: packet too big: %d > %d; from addr %E\n",
len, dlen, h->udpsrc);
continue;
}
memmove(data, h->udpcksum+sizeof(h->udpcksum), len);
a->ip = addr;
a->port = nhgets(h->udpsport);
memmove(a->ea, pkt.s, sizeof(a->ea));
rxactive = 1;
return len;
}
return 0;
}
static int tftpblockno;
/*
* format of a request packet, from the RFC:
*
2 bytes string 1 byte string 1 byte
------------------------------------------------
| Opcode | Filename | 0 | Mode | 0 |
------------------------------------------------
*/
static int
tftpopen(int ctlrno, Netaddr *a, char *name, Tftp *tftp)
{
int i, len, rlen, oport;
char buf[Segsize+2];
buf[0] = 0;
buf[1] = Tftp_READ;
len = 2 + sprint(buf+2, "%s", name) + 1;
len += sprint(buf+len, "octet") + 1;
oport = a->port;
for(i = 0; i < 5; i++){
a->port = oport;
udpsend(ctlrno, a, buf, len);
a->port = 0;
if((rlen = udprecv(ctlrno, a, tftp, sizeof(Tftp))) < sizeof(tftp->header))
continue;
switch((tftp->header[0]<<8)|tftp->header[1]){
case Tftp_ERROR:
print("tftpopen: error (%d): %s\n",
(tftp->header[2]<<8)|tftp->header[3], (char*)tftp->data);
return -1;
case Tftp_DATA:
tftpblockno = 1;
len = (tftp->header[2]<<8)|tftp->header[3];
if(len != tftpblockno){
print("tftpopen: block error: %d\n", len);
nak(ctlrno, a, 1, "block error", 0);
return -1;
}
rlen -= sizeof(tftp->header);
if(rlen < Segsize){
/* ACK now, in case we don't later */
buf[0] = 0;
buf[1] = Tftp_ACK;
buf[2] = tftpblockno>>8;
buf[3] = tftpblockno;
udpsend(ctlrno, a, buf, sizeof(tftp->header));
}
return rlen;
}
}
print("tftpopen: failed to connect to server\n");
return -1;
}
static int
tftpread(int ctlrno, Netaddr *a, Tftp *tftp, int dlen)
{
uchar buf[4];
int try, blockno, len;
dlen += sizeof(tftp->header);
for(try = 0; try < 10; try++) {
buf[0] = 0;
buf[1] = Tftp_ACK;
buf[2] = tftpblockno>>8;
buf[3] = tftpblockno;
udpsend(ctlrno, a, buf, sizeof(buf));
len = udprecv(ctlrno, a, tftp, dlen);
if(len <= sizeof(tftp->header)){
if(debug)
print("tftpread: too short %d <= %d\n",
len, sizeof(tftp->header));
continue;
}
blockno = (tftp->header[2]<<8)|tftp->header[3];
if(blockno <= tftpblockno){
if(debug)
print("tftpread: blkno %d <= %d\n",
blockno, tftpblockno);
continue;
}
if(blockno == tftpblockno+1) {
tftpblockno++;
if(len < dlen) { /* last packet; send final ack */
tftpblockno++;
buf[0] = 0;
buf[1] = Tftp_ACK;
buf[2] = tftpblockno>>8;
buf[3] = tftpblockno;
udpsend(ctlrno, a, buf, sizeof(buf));
}
return len-sizeof(tftp->header);
}
print("tftpread: block error: %d, expected %d\n",
blockno, tftpblockno+1);
}
return -1;
}
static int
bootpopen(int ctlrno, char *file, Bootp *rep, int dotftpopen)
{
Bootp req;
int i, n;
uchar *ea;
char name[128], *filename, *sysname;
if (debugload)
print("bootpopen: ether%d!%s...", ctlrno, file);
if((ea = etheraddr(ctlrno)) == 0){
print("invalid ctlrno %d\n", ctlrno);
return -1;
}
filename = 0;
sysname = 0;
if(file && *file){
strcpy(name, file);
if(filename = strchr(name, '!')){
sysname = name;
*filename++ = 0;
}
else
filename = name;
}
memset(&req, 0, sizeof(req));
req.op = Bootrequest;
req.htype = 1; /* ethernet */
req.hlen = Eaddrlen; /* ethernet */
memmove(req.chaddr, ea, Eaddrlen);
if(filename != nil)
strncpy(req.file, filename, sizeof(req.file));
if(sysname != nil)
strncpy(req.sname, sysname, sizeof(req.sname));
myaddr.ip = 0;
myaddr.port = BPportsrc;
memmove(myaddr.ea, ea, Eaddrlen);
etherrxflush(ctlrno);
for(i = 0; i < 10; i++) {
server.ip = Bcastip;
server.port = BPportdst;
memmove(server.ea, broadcast, sizeof(server.ea));
udpsend(ctlrno, &server, &req, sizeof(req));
if(udprecv(ctlrno, &server, rep, sizeof(*rep)) <= 0)
continue;
if(memcmp(req.chaddr, rep->chaddr, Eaddrlen))
continue;
if(rep->htype != 1 || rep->hlen != Eaddrlen)
continue;
if(sysname == 0 || strcmp(sysname, rep->sname) == 0)
break;
}
if(i >= 10) {
print("bootp timed out\n");
return -1;
}
if(!dotftpopen)
return 0;
if(filename == 0 || *filename == 0){
if(strcmp(rep->file, "/386/9pxeload") == 0)
return -1;
filename = rep->file;
}
if(rep->sname[0] != '\0')
print("%s ", rep->sname);
print("(%d.%d.%d.%d!%d): %s\n",
rep->siaddr[0],
rep->siaddr[1],
rep->siaddr[2],
rep->siaddr[3],
server.port,
filename);
myaddr.ip = nhgetl(rep->yiaddr);
myaddr.port = tftpport++;
server.ip = nhgetl(rep->siaddr);
server.port = TFTPport;
if((n = tftpopen(ctlrno, &server, filename, &tftpb)) < 0)
return -1;
return n;
}
int
bootpboot(int ctlrno, char *file, Boot *b)
{
int n;
Bootp rep;
if((n = bootpopen(ctlrno, file, &rep, 1)) < 0)
return -1;
while(bootpass(b, tftpb.data, n) == MORE){
n = tftpread(ctlrno, &server, &tftpb, sizeof(tftpb.data));
if(n < sizeof(tftpb.data))
break;
}
if(0 < n && n < sizeof(tftpb.data)) /* got to end of file */
bootpass(b, tftpb.data, n);
else
nak(ctlrno, &server, 3, "ok", 0); /* tftpclose to abort transfer */
bootpass(b, nil, 0); /* boot if possible */
return -1;
}
#include "fs.h"
#define INIPATHLEN 64
static struct {
Fs fs;
char ini[INIPATHLEN];
} pxether[MaxEther];
static vlong
pxediskseek(Fs*, vlong)
{
return -1LL;
}
static long
pxediskread(Fs*, void*, long)
{
return -1;
}
static long
pxeread(File* f, void* va, long len)
{
int n;
Bootp rep;
char *p, *v;
if((n = bootpopen(f->fs->dev, pxether[f->fs->dev].ini, &rep, 1)) < 0)
return -1;
p = v = va;
while(n > 0) {
if((p-v)+n > len)
n = len - (p-v);
memmove(p, tftpb.data, n);
p += n;
if(n != Segsize)
break;
if((n = tftpread(f->fs->dev, &server, &tftpb, sizeof(tftpb.data))) < 0)
return -1;
}
return p-v;
}
static int
pxewalk(File* f, char* name)
{
Bootp rep;
char *ini;
switch(f->walked){
default:
return -1;
case 0:
if(strcmp(name, "cfg") == 0){
f->walked = 1;
return 1;
}
break;
case 1:
if(strcmp(name, "pxe") == 0){
f->walked = 2;
return 1;
}
break;
case 2:
if(strcmp(name, "%E") != 0)
break;
f->walked = 3;
if(bootpopen(f->fs->dev, nil, &rep, 0) < 0)
return 0;
ini = pxether[f->fs->dev].ini;
/* use our mac address instead of relying on a bootp answer */
snprint(ini, INIPATHLEN, "/cfg/pxe/%E", (uchar *)myaddr.ea);
f->path = ini;
return 1;
}
return 0;
}
void*
pxegetfspart(int ctlrno, char* part, int)
{
if(!pxe)
return nil;
if(strcmp(part, "*") != 0)
return nil;
if(ctlrno >= MaxEther)
return nil;
if(iniread && getconf("*pxeini") != nil)
return nil;
pxether[ctlrno].fs.dev = ctlrno;
pxether[ctlrno].fs.diskread = pxediskread;
pxether[ctlrno].fs.diskseek = pxediskseek;
pxether[ctlrno].fs.read = pxeread;
pxether[ctlrno].fs.walk = pxewalk;
pxether[ctlrno].fs.root.fs = &pxether[ctlrno].fs;
pxether[ctlrno].fs.root.walked = 0;
return &pxether[ctlrno].fs;
}