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qemu/slirp/slirp.c

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#include "slirp.h"
/* host address */
struct in_addr our_addr;
/* host dns address */
struct in_addr dns_addr;
/* host loopback address */
struct in_addr loopback_addr;
/* address for slirp virtual addresses */
struct in_addr special_addr;
/* virtual address alias for host */
struct in_addr alias_addr;
const uint8_t special_ethaddr[6] = {
0x52, 0x54, 0x00, 0x12, 0x35, 0x00
};
uint8_t client_ethaddr[6];
int do_slowtimo;
int link_up;
struct timeval tt;
FILE *lfd;
struct ex_list *exec_list;
/* XXX: suppress those select globals */
fd_set *global_readfds, *global_writefds, *global_xfds;
char slirp_hostname[33];
#ifdef _WIN32
static int get_dns_addr(struct in_addr *pdns_addr)
{
FIXED_INFO *FixedInfo=NULL;
ULONG BufLen;
DWORD ret;
IP_ADDR_STRING *pIPAddr;
struct in_addr tmp_addr;
FixedInfo = (FIXED_INFO *)GlobalAlloc(GPTR, sizeof(FIXED_INFO));
BufLen = sizeof(FIXED_INFO);
if (ERROR_BUFFER_OVERFLOW == GetNetworkParams(FixedInfo, &BufLen)) {
if (FixedInfo) {
GlobalFree(FixedInfo);
FixedInfo = NULL;
}
FixedInfo = GlobalAlloc(GPTR, BufLen);
}
if ((ret = GetNetworkParams(FixedInfo, &BufLen)) != ERROR_SUCCESS) {
printf("GetNetworkParams failed. ret = %08x\n", (u_int)ret );
if (FixedInfo) {
GlobalFree(FixedInfo);
FixedInfo = NULL;
}
return -1;
}
pIPAddr = &(FixedInfo->DnsServerList);
inet_aton(pIPAddr->IpAddress.String, &tmp_addr);
*pdns_addr = tmp_addr;
#if 0
printf( "DNS Servers:\n" );
printf( "DNS Addr:%s\n", pIPAddr->IpAddress.String );
pIPAddr = FixedInfo -> DnsServerList.Next;
while ( pIPAddr ) {
printf( "DNS Addr:%s\n", pIPAddr ->IpAddress.String );
pIPAddr = pIPAddr ->Next;
}
#endif
if (FixedInfo) {
GlobalFree(FixedInfo);
FixedInfo = NULL;
}
return 0;
}
#else
static int get_dns_addr(struct in_addr *pdns_addr)
{
char buff[512];
char buff2[256];
FILE *f;
int found = 0;
struct in_addr tmp_addr;
f = fopen("/etc/resolv.conf", "r");
if (!f)
return -1;
lprint("IP address of your DNS(s): ");
while (fgets(buff, 512, f) != NULL) {
if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
if (!inet_aton(buff2, &tmp_addr))
continue;
if (tmp_addr.s_addr == loopback_addr.s_addr)
tmp_addr = our_addr;
/* If it's the first one, set it to dns_addr */
if (!found)
*pdns_addr = tmp_addr;
else
lprint(", ");
if (++found > 3) {
lprint("(more)");
break;
} else
lprint("%s", inet_ntoa(tmp_addr));
}
}
fclose(f);
if (!found)
return -1;
return 0;
}
#endif
#ifdef _WIN32
void slirp_cleanup(void)
{
WSACleanup();
}
#endif
void slirp_init(void)
{
// debug_init("/tmp/slirp.log", DEBUG_DEFAULT);
#ifdef _WIN32
{
WSADATA Data;
WSAStartup(MAKEWORD(2,0), &Data);
atexit(slirp_cleanup);
}
#endif
link_up = 1;
if_init();
ip_init();
/* Initialise mbufs *after* setting the MTU */
m_init();
/* set default addresses */
inet_aton("127.0.0.1", &loopback_addr);
if (get_dns_addr(&dns_addr) < 0) {
dns_addr = loopback_addr;
fprintf (stderr, "Warning: No DNS servers found\n");
}
inet_aton(CTL_SPECIAL, &special_addr);
alias_addr.s_addr = special_addr.s_addr | htonl(CTL_ALIAS);
getouraddr();
}
#define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
#define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
#define UPD_NFDS(x) if (nfds < (x)) nfds = (x)
/*
* curtime kept to an accuracy of 1ms
*/
#ifdef _WIN32
static void updtime(void)
{
struct _timeb tb;
_ftime(&tb);
curtime = (u_int)tb.time * (u_int)1000;
curtime += (u_int)tb.millitm;
}
#else
static void updtime(void)
{
gettimeofday(&tt, 0);
curtime = (u_int)tt.tv_sec * (u_int)1000;
curtime += (u_int)tt.tv_usec / (u_int)1000;
if ((tt.tv_usec % 1000) >= 500)
curtime++;
}
#endif
void slirp_select_fill(int *pnfds,
fd_set *readfds, fd_set *writefds, fd_set *xfds)
{
struct socket *so, *so_next;
struct timeval timeout;
int nfds;
int tmp_time;
/* fail safe */
global_readfds = NULL;
global_writefds = NULL;
global_xfds = NULL;
nfds = *pnfds;
/*
* First, TCP sockets
*/
do_slowtimo = 0;
if (link_up) {
/*
* *_slowtimo needs calling if there are IP fragments
* in the fragment queue, or there are TCP connections active
*/
do_slowtimo = ((tcb.so_next != &tcb) ||
((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next));
for (so = tcb.so_next; so != &tcb; so = so_next) {
so_next = so->so_next;
/*
* See if we need a tcp_fasttimo
*/
if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK)
time_fasttimo = curtime; /* Flag when we want a fasttimo */
/*
* NOFDREF can include still connecting to local-host,
* newly socreated() sockets etc. Don't want to select these.
*/
if (so->so_state & SS_NOFDREF || so->s == -1)
continue;
/*
* Set for reading sockets which are accepting
*/
if (so->so_state & SS_FACCEPTCONN) {
FD_SET(so->s, readfds);
UPD_NFDS(so->s);
continue;
}
/*
* Set for writing sockets which are connecting
*/
if (so->so_state & SS_ISFCONNECTING) {
FD_SET(so->s, writefds);
UPD_NFDS(so->s);
continue;
}
/*
* Set for writing if we are connected, can send more, and
* we have something to send
*/
if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) {
FD_SET(so->s, writefds);
UPD_NFDS(so->s);
}
/*
* Set for reading (and urgent data) if we are connected, can
* receive more, and we have room for it XXX /2 ?
*/
if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) {
FD_SET(so->s, readfds);
FD_SET(so->s, xfds);
UPD_NFDS(so->s);
}
}
/*
* UDP sockets
*/
for (so = udb.so_next; so != &udb; so = so_next) {
so_next = so->so_next;
/*
* See if it's timed out
*/
if (so->so_expire) {
if (so->so_expire <= curtime) {
udp_detach(so);
continue;
} else
do_slowtimo = 1; /* Let socket expire */
}
/*
* When UDP packets are received from over the
* link, they're sendto()'d straight away, so
* no need for setting for writing
* Limit the number of packets queued by this session
* to 4. Note that even though we try and limit this
* to 4 packets, the session could have more queued
* if the packets needed to be fragmented
* (XXX <= 4 ?)
*/
if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) {
FD_SET(so->s, readfds);
UPD_NFDS(so->s);
}
}
}
/*
* Setup timeout to use minimum CPU usage, especially when idle
*/
/*
* First, see the timeout needed by *timo
*/
timeout.tv_sec = 0;
timeout.tv_usec = -1;
/*
* If a slowtimo is needed, set timeout to 500ms from the last
* slow timeout. If a fast timeout is needed, set timeout within
* 200ms of when it was requested.
*/
if (do_slowtimo) {
/* XXX + 10000 because some select()'s aren't that accurate */
timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000;
if (timeout.tv_usec < 0)
timeout.tv_usec = 0;
else if (timeout.tv_usec > 510000)
timeout.tv_usec = 510000;
/* Can only fasttimo if we also slowtimo */
if (time_fasttimo) {
tmp_time = (200 - (curtime - time_fasttimo)) * 1000;
if (tmp_time < 0)
tmp_time = 0;
/* Choose the smallest of the 2 */
if (tmp_time < timeout.tv_usec)
timeout.tv_usec = (u_int)tmp_time;
}
}
*pnfds = nfds;
}
void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds)
{
struct socket *so, *so_next;
int ret;
global_readfds = readfds;
global_writefds = writefds;
global_xfds = xfds;
/* Update time */
updtime();
/*
* See if anything has timed out
*/
if (link_up) {
if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) {
tcp_fasttimo();
time_fasttimo = 0;
}
if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) {
ip_slowtimo();
tcp_slowtimo();
last_slowtimo = curtime;
}
}
/*
* Check sockets
*/
if (link_up) {
/*
* Check TCP sockets
*/
for (so = tcb.so_next; so != &tcb; so = so_next) {
so_next = so->so_next;
/*
* FD_ISSET is meaningless on these sockets
* (and they can crash the program)
*/
if (so->so_state & SS_NOFDREF || so->s == -1)
continue;
/*
* Check for URG data
* This will soread as well, so no need to
* test for readfds below if this succeeds
*/
if (FD_ISSET(so->s, xfds))
sorecvoob(so);
/*
* Check sockets for reading
*/
else if (FD_ISSET(so->s, readfds)) {
/*
* Check for incoming connections
*/
if (so->so_state & SS_FACCEPTCONN) {
tcp_connect(so);
continue;
} /* else */
ret = soread(so);
/* Output it if we read something */
if (ret > 0)
tcp_output(sototcpcb(so));
}
/*
* Check sockets for writing
*/
if (FD_ISSET(so->s, writefds)) {
/*
* Check for non-blocking, still-connecting sockets
*/
if (so->so_state & SS_ISFCONNECTING) {
/* Connected */
so->so_state &= ~SS_ISFCONNECTING;
ret = send(so->s, &ret, 0, 0);
if (ret < 0) {
/* XXXXX Must fix, zero bytes is a NOP */
if (errno == EAGAIN || errno == EWOULDBLOCK ||
errno == EINPROGRESS || errno == ENOTCONN)
continue;
/* else failed */
so->so_state = SS_NOFDREF;
}
/* else so->so_state &= ~SS_ISFCONNECTING; */
/*
* Continue tcp_input
*/
tcp_input((struct mbuf *)NULL, sizeof(struct ip), so);
/* continue; */
} else
ret = sowrite(so);
/*
* XXXXX If we wrote something (a lot), there
* could be a need for a window update.
* In the worst case, the remote will send
* a window probe to get things going again
*/
}
/*
* Probe a still-connecting, non-blocking socket
* to check if it's still alive
*/
#ifdef PROBE_CONN
if (so->so_state & SS_ISFCONNECTING) {
ret = recv(so->s, (char *)&ret, 0,0);
if (ret < 0) {
/* XXX */
if (errno == EAGAIN || errno == EWOULDBLOCK ||
errno == EINPROGRESS || errno == ENOTCONN)
continue; /* Still connecting, continue */
/* else failed */
so->so_state = SS_NOFDREF;
/* tcp_input will take care of it */
} else {
ret = send(so->s, &ret, 0,0);
if (ret < 0) {
/* XXX */
if (errno == EAGAIN || errno == EWOULDBLOCK ||
errno == EINPROGRESS || errno == ENOTCONN)
continue;
/* else failed */
so->so_state = SS_NOFDREF;
} else
so->so_state &= ~SS_ISFCONNECTING;
}
tcp_input((struct mbuf *)NULL, sizeof(struct ip),so);
} /* SS_ISFCONNECTING */
#endif
}
/*
* Now UDP sockets.
* Incoming packets are sent straight away, they're not buffered.
* Incoming UDP data isn't buffered either.
*/
for (so = udb.so_next; so != &udb; so = so_next) {
so_next = so->so_next;
if (so->s != -1 && FD_ISSET(so->s, readfds)) {
sorecvfrom(so);
}
}
}
/*
* See if we can start outputting
*/
if (if_queued && link_up)
if_start();
/* clear global file descriptor sets.
* these reside on the stack in vl.c
* so they're unusable if we're not in
* slirp_select_fill or slirp_select_poll.
*/
global_readfds = NULL;
global_writefds = NULL;
global_xfds = NULL;
}
#define ETH_ALEN 6
#define ETH_HLEN 14
#define ETH_P_IP 0x0800 /* Internet Protocol packet */
#define ETH_P_ARP 0x0806 /* Address Resolution packet */
#define ARPOP_REQUEST 1 /* ARP request */
#define ARPOP_REPLY 2 /* ARP reply */
struct ethhdr
{
unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
unsigned char h_source[ETH_ALEN]; /* source ether addr */
unsigned short h_proto; /* packet type ID field */
};
struct arphdr
{
unsigned short ar_hrd; /* format of hardware address */
unsigned short ar_pro; /* format of protocol address */
unsigned char ar_hln; /* length of hardware address */
unsigned char ar_pln; /* length of protocol address */
unsigned short ar_op; /* ARP opcode (command) */
/*
* Ethernet looks like this : This bit is variable sized however...
*/
unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */
unsigned char ar_sip[4]; /* sender IP address */
unsigned char ar_tha[ETH_ALEN]; /* target hardware address */
unsigned char ar_tip[4]; /* target IP address */
};
void arp_input(const uint8_t *pkt, int pkt_len)
{
struct ethhdr *eh = (struct ethhdr *)pkt;
struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN);
uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)];
struct ethhdr *reh = (struct ethhdr *)arp_reply;
struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN);
int ar_op;
struct ex_list *ex_ptr;
ar_op = ntohs(ah->ar_op);
switch(ar_op) {
case ARPOP_REQUEST:
if (!memcmp(ah->ar_tip, &special_addr, 3)) {
if (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS)
goto arp_ok;
for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
if (ex_ptr->ex_addr == ah->ar_tip[3])
goto arp_ok;
}
return;
arp_ok:
/* XXX: make an ARP request to have the client address */
memcpy(client_ethaddr, eh->h_source, ETH_ALEN);
/* ARP request for alias/dns mac address */
memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN);
memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1);
reh->h_source[5] = ah->ar_tip[3];
reh->h_proto = htons(ETH_P_ARP);
rah->ar_hrd = htons(1);
rah->ar_pro = htons(ETH_P_IP);
rah->ar_hln = ETH_ALEN;
rah->ar_pln = 4;
rah->ar_op = htons(ARPOP_REPLY);
memcpy(rah->ar_sha, reh->h_source, ETH_ALEN);
memcpy(rah->ar_sip, ah->ar_tip, 4);
memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN);
memcpy(rah->ar_tip, ah->ar_sip, 4);
slirp_output(arp_reply, sizeof(arp_reply));
}
break;
default:
break;
}
}
void slirp_input(const uint8_t *pkt, int pkt_len)
{
struct mbuf *m;
int proto;
if (pkt_len < ETH_HLEN)
return;
proto = ntohs(*(uint16_t *)(pkt + 12));
switch(proto) {
case ETH_P_ARP:
arp_input(pkt, pkt_len);
break;
case ETH_P_IP:
m = m_get();
if (!m)
return;
/* Note: we add to align the IP header */
m->m_len = pkt_len + 2;
memcpy(m->m_data + 2, pkt, pkt_len);
m->m_data += 2 + ETH_HLEN;
m->m_len -= 2 + ETH_HLEN;
ip_input(m);
break;
default:
break;
}
}
/* output the IP packet to the ethernet device */
void if_encap(const uint8_t *ip_data, int ip_data_len)
{
uint8_t buf[1600];
struct ethhdr *eh = (struct ethhdr *)buf;
if (ip_data_len + ETH_HLEN > sizeof(buf))
return;
memcpy(eh->h_dest, client_ethaddr, ETH_ALEN);
memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1);
/* XXX: not correct */
eh->h_source[5] = CTL_ALIAS;
eh->h_proto = htons(ETH_P_IP);
memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len);
slirp_output(buf, ip_data_len + ETH_HLEN);
}
int slirp_redir(int is_udp, int host_port,
struct in_addr guest_addr, int guest_port)
{
if (is_udp) {
if (!udp_listen(htons(host_port), guest_addr.s_addr,
htons(guest_port), 0))
return -1;
} else {
if (!solisten(htons(host_port), guest_addr.s_addr,
htons(guest_port), 0))
return -1;
}
return 0;
}
int slirp_add_exec(int do_pty, const char *args, int addr_low_byte,
int guest_port)
{
return add_exec(&exec_list, do_pty, (char *)args,
addr_low_byte, htons(guest_port));
}
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