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1bb3e86457
Bochs/bochs/iodev/eth_slirp.cc
Volker Ruppert e5f40d7188 - missing DHCP error handling added 
- don't forward DHCP request to Slirp
- improved comments
2011-03-02 17:51:52 +00:00

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/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011 Heikki Lindholm
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
//
// eth_slirp.cc - slirp backend to eth
#define BX_PLUGGABLE
#include "iodev.h"
#if BX_NETWORKING && BX_NETMOD_SLIRP
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <stdint.h>
#include <arpa/inet.h> /* ntohs, htons */
#include "eth.h"
#define LOG_THIS netdev->
#define BX_ETH_SLIRP_LOGGING 0
#if defined(_MSC_VER)
#pragma pack(push, 1)
#elif defined(__MWERKS__) && defined(macintosh)
#pragma options align=packed
#endif
// this should not be smaller than an arp reply with an ethernet header
#define MIN_RX_PACKET_LEN 60
#define ETHERNET_MAC_ADDR_LEN 6
#define ETHERNET_TYPE_IPV4 0x0800
#define ETHERNET_TYPE_ARP 0x0806
typedef struct ethernet_header {
#if defined(_MSC_VER) && (_MSC_VER>=1300)
__declspec(align(1))
#endif
Bit8u dst_mac_addr[ETHERNET_MAC_ADDR_LEN];
Bit8u src_mac_addr[ETHERNET_MAC_ADDR_LEN];
Bit16u type;
}
#if !defined(_MSC_VER)
GCC_ATTRIBUTE((packed))
#endif
ethernet_header_t;
#define ARP_OPCODE_REQUEST 1
#define ARP_OPCODE_REPLY 2
typedef struct arp_header {
#if defined(_MSC_VER) && (_MSC_VER>=1300)
__declspec(align(1))
#endif
Bit16u hw_addr_space;
Bit16u proto_addr_space;
Bit8u hw_addr_len;
Bit8u proto_addr_len;
Bit16u opcode;
/* HW address of sender */
/* Protocol address of sender */
/* HW address of target*/
/* Protocol address of target */
}
#if !defined(_MSC_VER)
GCC_ATTRIBUTE((packed))
#endif
arp_header_t;
#if defined(_MSC_VER)
#pragma pack(pop)
#elif defined(__MWERKS__) && defined(macintosh)
#pragma options align=reset
#endif
const Bit8u default_host_ipv4addr[4] = {10, 0, 2, 2};
const Bit8u default_dns_ipv4addr[4] = {10, 0, 2, 3};
const Bit8u default_guest_ipv4addr[4] = {10, 0, 2, 15};
const Bit8u broadcast_ipv4addr[3][4] =
{
{ 0, 0, 0, 0},
{255,255,255,255},
{ 10, 0, 2,255},
};
#define SLIP_END 192
#define SLIP_ESC 219
#define SLIP_ESC_END 220
#define SLIP_ESC_ESC 221
static size_t encode_slip(Bit8u *src, Bit8u *dst, size_t src_len)
{
Bit8u *dst_start = dst;
Bit8u *src_end = src + src_len;
while (src < src_end) {
switch (*src) {
case SLIP_END:
*dst++ = SLIP_ESC;
*dst++ = SLIP_ESC_END;
break;
case SLIP_ESC:
*dst++ = SLIP_ESC;
*dst++ = SLIP_ESC_ESC;
break;
default:
*dst++ = *src;
break;
}
src++;
}
*dst++ = SLIP_END;
return dst - dst_start;
}
static int decode_slip(Bit8u *src, size_t *src_len, Bit8u *dst, size_t *dst_len)
{
Bit8u *dst_start = dst;
Bit8u *src_start = src;
Bit8u *src_end = src + *src_len;
int got_packet = 0;
if (*src_len == 0) {
*dst_len = 0;
return 0;
}
while ((src < (src_end - 1)) && (!got_packet)) {
switch (*src) {
case SLIP_END:
if (dst != dst_start) // discard empty packets
got_packet = 1;
src++;
break;
case SLIP_ESC:
switch (*++src) {
case SLIP_ESC_ESC:
*dst++ = SLIP_ESC;
src++;
break;
case SLIP_ESC_END:
*dst++ = SLIP_END;
src++;
break;
default:
*dst++ = *src++;
break;
}
break;
default:
*dst++ = *src++;
break;
}
}
if ((!got_packet) && (src < src_end)) {
switch (*src) {
case SLIP_END:
got_packet = 1;
src++;
break;
case SLIP_ESC:
break;
default:
*dst++ = *src++;
break;
}
}
*src_len = src - src_start;
*dst_len = dst - dst_start;
return got_packet;
}
class bx_slirp_pktmover_c : public eth_pktmover_c {
public:
bx_slirp_pktmover_c(const char *netif, const char *macaddr,
eth_rx_handler_t rxh,
bx_devmodel_c *dev, const char *script);
void sendpkt(void *buf, unsigned io_len);
private:
pid_t slirp_pid;
int slirp_pipe_fds[2];
Bit8u slip_output_buffer[4096]; // TODO: reasonable size for these?
Bit8u slip_input_buffer[4096];
size_t slip_input_buffer_filled;
size_t slip_input_buffer_decoded;
Bit8u reply_buffer[1024];
int pending_reply_size;
dhcp_cfg_t dhcp;
int rx_timer_index;
unsigned tx_time;
static void rx_timer_handler(void *);
void rx_timer();
bx_bool handle_ipv4(const Bit8u *buf, unsigned len);
void handle_arp(void *buf, unsigned len);
void prepare_builtin_reply(unsigned type);
#if BX_ETH_SLIRP_LOGGING
FILE *pktlog_txt;
#endif
};
class bx_slirp_locator_c : public eth_locator_c {
public:
bx_slirp_locator_c(void) : eth_locator_c("slirp") {}
protected:
eth_pktmover_c *allocate(const char *netif, const char *macaddr,
eth_rx_handler_t rxh,
bx_devmodel_c *dev, const char *script) {
return (new bx_slirp_pktmover_c(netif, macaddr, rxh, dev, script));
}
} bx_slirp_match;
bx_slirp_pktmover_c::bx_slirp_pktmover_c(const char *netif,
const char *macaddr,
eth_rx_handler_t rxh,
bx_devmodel_c *dev,
const char *script)
{
int flags;
this->netdev = dev;
BX_INFO(("slirp network driver"));
if (socketpair(AF_UNIX, SOCK_STREAM, 0, slirp_pipe_fds))
BX_PANIC(("socketpair() failed: %s", strerror(errno)));
// mark our end of the pipe non-blocking because of the timer based poll
flags = fcntl(slirp_pipe_fds[0], F_GETFL);
if (flags == -1)
BX_PANIC(("fcntl(,F_GETFL) failed: %s", strerror(errno)));
flags |= O_NONBLOCK;
if (fcntl (slirp_pipe_fds[0], F_SETFL, flags) != 0)
BX_PANIC(("fcntl(,F_SETFL,) failed: %s", strerror(errno)));
slirp_pid = fork();
if (slirp_pid == -1) {
BX_PANIC(("fork() failed: %s", strerror(errno)));
}
else if (slirp_pid == 0) {
int ret;
int nfd;
nfd = open("/dev/null", O_RDWR);
if (nfd != -1) {
dup2(nfd, STDERR_FILENO);
}
if (dup2(slirp_pipe_fds[1], STDIN_FILENO) == -1) {
BX_PANIC(("dup2() failed: %s", strerror(errno)));
}
/* XXX slirp seems to use stdin bidirectionally
* instead of using stdout for SLIP output */
if (dup2(slirp_pipe_fds[1], STDOUT_FILENO) == -1) {
BX_PANIC(("dup2() failed: %s", strerror(errno)));
}
close(slirp_pipe_fds[0]);
ret = execlp(script == NULL ? "slirp" : script,
script == NULL ? "slirp" : script, /*"-d", "-1", "-S",*/ NULL);
if (ret == -1) {
BX_PANIC(("execlp() failed: %s", strerror(errno)));
}
}
this->rx_timer_index =
bx_pc_system.register_timer(this, this->rx_timer_handler, 1000,
1, 1, "eth_slirp");
this->rxh = rxh;
memcpy(&dhcp.guest_macaddr[0], macaddr, ETHERNET_MAC_ADDR_LEN);
// ensure the slirp host has a different mac address
memcpy(&dhcp.host_macaddr[0], macaddr, ETHERNET_MAC_ADDR_LEN);
dhcp.host_macaddr[5] ^= 0x03;
memcpy(&dhcp.host_ipv4addr[0], &default_host_ipv4addr[0], 4);
memcpy(&dhcp.guest_ipv4addr[0], &broadcast_ipv4addr[1][0], 4);
dhcp.default_guest_ipv4addr = default_guest_ipv4addr;
memcpy(&dhcp.dns_ipv4addr[0], &default_dns_ipv4addr[0], 4);
pending_reply_size = 0;
slip_input_buffer_filled = slip_input_buffer_decoded = 0;
close(slirp_pipe_fds[1]);
#if BX_ETH_SLIRP_LOGGING
pktlog_txt = fopen("ne2k-pktlog.txt", "wb");
if (!pktlog_txt) BX_PANIC(("ne2k-pktlog.txt failed"));
fprintf(pktlog_txt, "slirp packetmover readable log file\n");
fprintf(pktlog_txt, "host MAC address = ");
int i;
for (i=0; i<6; i++)
fprintf(pktlog_txt, "%02x%s", 0xff & host_mac_addr[i], i<5?":" : "\n");
fprintf(pktlog_txt, "guest MAC address = ");
for (i=0; i<6; i++)
fprintf(pktlog_txt, "%02x%s", 0xff & guest_mac_addr[i], i<5?":" : "\n");
fprintf(pktlog_txt, "--\n");
fflush(pktlog_txt);
#endif
}
void bx_slirp_pktmover_c::handle_arp(void *buf, unsigned len)
{
arp_header_t *arphdr = (arp_header_t *)((Bit8u *)buf +
sizeof(ethernet_header_t));
if (pending_reply_size > 0)
return;
if ((ntohs(arphdr->hw_addr_space) != 0x0001) ||
(ntohs(arphdr->proto_addr_space) != 0x0800) ||
(arphdr->hw_addr_len != ETHERNET_MAC_ADDR_LEN) ||
(arphdr->proto_addr_len != 4)) {
BX_ERROR(("Unhandled ARP message hw: %04x (%d) proto: %04x (%d)\n",
ntohs(arphdr->hw_addr_space), arphdr->hw_addr_len,
ntohs(arphdr->proto_addr_space), arphdr->proto_addr_len));
return;
}
arp_header_t *arprhdr = (arp_header_t *)((Bit8u *)reply_buffer +
sizeof(ethernet_header_t));
switch(ntohs(arphdr->opcode)) {
case ARP_OPCODE_REQUEST:
// Slirp uses addresses x.x.x.0 - x.x.x.3
if (((Bit8u *)arphdr)[27] > 3)
break;
memset(reply_buffer, 0, MIN_RX_PACKET_LEN);
arprhdr->hw_addr_space = htons(0x0001);
arprhdr->proto_addr_space = htons(0x0800);
arprhdr->hw_addr_len = ETHERNET_MAC_ADDR_LEN;
arprhdr->proto_addr_len = 4;
arprhdr->opcode = htons(ARP_OPCODE_REPLY);
memcpy((Bit8u *)arprhdr+8, dhcp.host_macaddr, ETHERNET_MAC_ADDR_LEN);
memcpy((Bit8u *)arprhdr+14, (Bit8u *)arphdr+24, 4);
memcpy((Bit8u *)arprhdr+18, dhcp.guest_macaddr, ETHERNET_MAC_ADDR_LEN);
memcpy((Bit8u *)arprhdr+24, (Bit8u *)arphdr+14, 4);
pending_reply_size = MIN_RX_PACKET_LEN;
prepare_builtin_reply(ETHERNET_TYPE_ARP);
break;
case ARP_OPCODE_REPLY:
break;
default:
break;
}
}
// detect and handle DHCP request (partly copy & paste from eth_vnet.cc)
bx_bool bx_slirp_pktmover_c::handle_ipv4(const Bit8u *buf, unsigned len)
{
unsigned total_len;
unsigned fragment_flags;
unsigned fragment_offset;
unsigned ipproto;
unsigned l3header_len;
const Bit8u *l4pkt;
unsigned l4pkt_len;
unsigned udp_sourceport;
unsigned udp_targetport;
unsigned dhcp_reply_size;
// guest-to-host IPv4
if (len < (14U+20U)) {
return 0;
}
if ((buf[14+0] & 0xf0) != 0x40) {
return 0;
}
l3header_len = ((unsigned)(buf[14+0] & 0x0f) << 2);
if (l3header_len != 20) {
return 0;
}
if (len < (14U+l3header_len)) return 0;
if (ip_checksum(&buf[14],l3header_len) != (Bit16u)0xffff) {
return 0;
}
total_len = get_net2(&buf[14+2]);
if (memcmp(&buf[14+16],dhcp.host_ipv4addr, 4) &&
memcmp(&buf[14+16],broadcast_ipv4addr[0],4) &&
memcmp(&buf[14+16],broadcast_ipv4addr[1],4) &&
memcmp(&buf[14+16],broadcast_ipv4addr[2],4))
{
return 0;
}
fragment_flags = (unsigned)buf[14+6] >> 5;
fragment_offset = ((unsigned)get_net2(&buf[14+6]) & 0x1fff) << 3;
ipproto = buf[14+9];
if ((fragment_flags & 0x1) || (fragment_offset != 0)) {
return 0;
} else {
l4pkt = &buf[14 + l3header_len];
l4pkt_len = total_len - l3header_len;
}
if (ipproto == 0x11) {
// guest-to-host UDP IPv4
if (l4pkt_len < 8) return 0;
udp_sourceport = get_net2(&l4pkt[0]);
udp_targetport = get_net2(&l4pkt[2]);
if (udp_targetport == 67) { // BOOTP
dhcp_reply_size = process_dhcp(netdev, &l4pkt[8], l4pkt_len-8, &reply_buffer[42], &dhcp);
if (dhcp_reply_size > 0) {
pending_reply_size = dhcp_reply_size + 42;
// host-to-guest UDP IPv4: pseudo-header
reply_buffer[22] = 0;
reply_buffer[23] = 0x11; // UDP
put_net2(&reply_buffer[24], 8U+dhcp_reply_size);
memcpy(&reply_buffer[26], dhcp.host_ipv4addr, 4);
memcpy(&reply_buffer[30], dhcp.guest_ipv4addr, 4);
// udp header
put_net2(&reply_buffer[34], udp_targetport);
put_net2(&reply_buffer[36], udp_sourceport);
put_net2(&reply_buffer[38], 8U+dhcp_reply_size);
put_net2(&reply_buffer[40], 0);
put_net2(&reply_buffer[40], ip_checksum(&reply_buffer[22], 12U+8U+dhcp_reply_size) ^ (Bit16u)0xffff);
// ip header
memset(&reply_buffer[14], 0, 20);
reply_buffer[14] = 0x45;
reply_buffer[15] = 0x00;
put_net2(&reply_buffer[16], 20U+8U+dhcp_reply_size);
put_net2(&reply_buffer[18], 1);
reply_buffer[20] = 0x00;
reply_buffer[21] = 0x00;
reply_buffer[22] = 0x07; // TTL
reply_buffer[23] = 0x11; // UDP
// host-to-guest IPv4
reply_buffer[14] = (reply_buffer[14] & 0x0f) | 0x40;
l3header_len = ((unsigned)(reply_buffer[14] & 0x0f) << 2);
memcpy(&reply_buffer[26], &dhcp.host_ipv4addr[0], 4);
memcpy(&reply_buffer[30], &dhcp.guest_ipv4addr[0], 4);
put_net2(&reply_buffer[24], 0);
put_net2(&reply_buffer[24], ip_checksum(&reply_buffer[14], l3header_len) ^ (Bit16u)0xffff);
prepare_builtin_reply(ETHERNET_TYPE_IPV4);
}
// don't forward DHCP request to Slirp
return 1;
}
}
return 0;
}
void bx_slirp_pktmover_c::sendpkt(void *buf, unsigned io_len)
{
size_t len;
ethernet_header_t *ethhdr = (ethernet_header_t *)buf;
#if BX_ETH_SLIRP_LOGGING
write_pktlog_txt(pktlog_txt, (Bit8u*)buf, io_len, 0);
#endif
this->tx_time = (64 + 96 + 4 * 8 + io_len * 8) / 10;
switch (ntohs(ethhdr->type)) {
case ETHERNET_TYPE_IPV4:
if (!handle_ipv4((Bit8u*)buf, io_len)) {
len = encode_slip((Bit8u *)buf+sizeof(ethernet_header_t),
slip_output_buffer,
io_len-sizeof(ethernet_header_t));
len = write(slirp_pipe_fds[0], slip_output_buffer, len);
}
break;
case ETHERNET_TYPE_ARP:
handle_arp(buf, io_len);
break;
default:
break;
}
}
void bx_slirp_pktmover_c::prepare_builtin_reply(unsigned type)
{
ethernet_header_t *ethhdr;
unsigned rx_time;
ethhdr = (ethernet_header_t *)reply_buffer;
memcpy(ethhdr->dst_mac_addr, dhcp.guest_macaddr, ETHERNET_MAC_ADDR_LEN);
memcpy(ethhdr->src_mac_addr, dhcp.host_macaddr, ETHERNET_MAC_ADDR_LEN);
ethhdr->type = htons(type);
rx_time = (64 + 96 + 4 * 8 + pending_reply_size * 8) / 10;
bx_pc_system.activate_timer(this->rx_timer_index, this->tx_time + rx_time + 100, 0);
}
void bx_slirp_pktmover_c::rx_timer_handler(void *this_ptr)
{
bx_slirp_pktmover_c *class_ptr = (bx_slirp_pktmover_c *)this_ptr;
class_ptr->rx_timer();
}
void bx_slirp_pktmover_c::rx_timer()
{
Bit8u *packet;
Bit8u padded_packet[MIN_RX_PACKET_LEN];
ethernet_header_t *ethhdr;
size_t packet_len;
if (pending_reply_size > 0) {
#if BX_ETH_SLIRP_LOGGING
write_pktlog_txt(pktlog_txt, reply_buffer, pending_reply_size, 1);
#endif
(*rxh)(this->netdev, reply_buffer, pending_reply_size);
pending_reply_size = 0;
// restore timer
bx_pc_system.activate_timer(this->rx_timer_index, 1000, 1);
return;
}
Bit8u *buf = slip_input_buffer + sizeof(ethernet_header_t);
ssize_t n;
int got_packet;
size_t ilen, olen, pos;
if (slip_input_buffer_filled + sizeof(ethernet_header_t) <
sizeof(slip_input_buffer)) {
n = read(slirp_pipe_fds[0], buf+slip_input_buffer_filled,
(sizeof(slip_input_buffer) - sizeof(ethernet_header_t)) -
slip_input_buffer_filled);
if (n < 1)
return;
slip_input_buffer_filled += n;
}
packet = (Bit8u *)slip_input_buffer;
ethhdr = (ethernet_header_t *)packet;
memcpy(ethhdr->dst_mac_addr, dhcp.guest_macaddr, ETHERNET_MAC_ADDR_LEN);
memcpy(ethhdr->src_mac_addr, dhcp.host_macaddr, ETHERNET_MAC_ADDR_LEN);
ethhdr->type = htons(ETHERNET_TYPE_IPV4);
olen = 0;
pos = slip_input_buffer_decoded;
do {
ilen = slip_input_buffer_filled - slip_input_buffer_decoded;
got_packet = decode_slip(buf + pos, &ilen,
buf + slip_input_buffer_decoded, &olen);
pos += ilen;
slip_input_buffer_filled -= ilen;
slip_input_buffer_filled += olen;
slip_input_buffer_decoded += olen;
if (got_packet) {
packet_len = sizeof(ethernet_header_t) + slip_input_buffer_decoded;
if (packet_len < MIN_RX_PACKET_LEN) {
packet = padded_packet;
bzero(packet, MIN_RX_PACKET_LEN);
memcpy(packet, slip_input_buffer, packet_len);
packet_len = MIN_RX_PACKET_LEN;
}
#if BX_ETH_SLIRP_LOGGING
write_pktlog_txt(pktlog_txt, packet, packet_len, 1);
#endif
(*rxh)(this->netdev, packet, packet_len);
slip_input_buffer_filled -= slip_input_buffer_decoded;
slip_input_buffer_decoded = 0;
}
} while (got_packet);
if ((slip_input_buffer_filled - slip_input_buffer_decoded) > 0)
memmove(slip_input_buffer + slip_input_buffer_decoded,
slip_input_buffer + pos,
(slip_input_buffer_filled - slip_input_buffer_decoded));
}
#endif /* if BX_NETWORKING && BX_NETMOD_SLIRP */
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