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qemu / libslirp / 32bea29d04c24be75c3169ea6ad107e4c3828691 / . / src / tcp_subr.c
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/* SPDX-License-Identifier: BSD-3-Clause */
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp_subr.c 8.1 (Berkeley) 6/10/93
* tcp_subr.c,v 1.5 1994/10/08 22:39:58 phk Exp
*/
/*
* Changes and additions relating to SLiRP
* Copyright (c) 1995 Danny Gasparovski.
*/
#include "slirp.h"
/* patchable/settable parameters for tcp */
/* Don't do rfc1323 performance enhancements */
#define TCP_DO_RFC1323 0
/*
* Tcp initialization
*/
void tcp_init(Slirp *slirp)
{
slirp->tcp_iss = 1; /* wrong */
slirp->tcb.so_next = slirp->tcb.so_prev = &slirp->tcb;
slirp->tcp_last_so = &slirp->tcb;
}
void tcp_cleanup(Slirp *slirp)
{
while (slirp->tcb.so_next != &slirp->tcb) {
tcp_close(sototcpcb(slirp->tcb.so_next));
}
}
/*
* Create template to be used to send tcp packets on a connection.
* Call after host entry created, fills
* in a skeletal tcp/ip header, minimizing the amount of work
* necessary when the connection is used.
*/
void tcp_template(struct tcpcb *tp)
{
struct socket *so = tp->t_socket;
register struct tcpiphdr *n = &tp->t_template;
n->ti_mbuf = NULL;
memset(&n->ti, 0, sizeof(n->ti));
n->ti_x0 = 0;
switch (so->so_ffamily) {
case AF_INET:
n->ti_pr = IPPROTO_TCP;
n->ti_len = htons(sizeof(struct tcphdr));
n->ti_src = so->so_faddr;
n->ti_dst = so->so_laddr;
n->ti_sport = so->so_fport;
n->ti_dport = so->so_lport;
break;
case AF_INET6:
n->ti_nh6 = IPPROTO_TCP;
n->ti_len = htons(sizeof(struct tcphdr));
n->ti_src6 = so->so_faddr6;
n->ti_dst6 = so->so_laddr6;
n->ti_sport = so->so_fport6;
n->ti_dport = so->so_lport6;
break;
default:
g_assert_not_reached();
}
n->ti_seq = 0;
n->ti_ack = 0;
n->ti_x2 = 0;
n->ti_off = 5;
n->ti_flags = 0;
n->ti_win = 0;
n->ti_sum = 0;
n->ti_urp = 0;
}
/*
* Send a single message to the TCP at address specified by
* the given TCP/IP header. If m == 0, then we make a copy
* of the tcpiphdr at ti and send directly to the addressed host.
* This is used to force keep alive messages out using the TCP
* template for a connection tp->t_template. If flags are given
* then we send a message back to the TCP which originated the
* segment ti, and discard the mbuf containing it and any other
* attached mbufs.
*
* In any case the ack and sequence number of the transmitted
* segment are as specified by the parameters.
*/
void tcp_respond(struct tcpcb *tp, struct tcpiphdr *ti, struct mbuf *m,
tcp_seq ack, tcp_seq seq, int flags, unsigned short af)
{
register int tlen;
int win = 0;
DEBUG_CALL("tcp_respond");
DEBUG_ARG("tp = %p", tp);
DEBUG_ARG("ti = %p", ti);
DEBUG_ARG("m = %p", m);
DEBUG_ARG("ack = %u", ack);
DEBUG_ARG("seq = %u", seq);
DEBUG_ARG("flags = %x", flags);
if (tp)
win = sbspace(&tp->t_socket->so_rcv);
if (m == NULL) {
if (!tp || (m = m_get(tp->t_socket->slirp)) == NULL)
return;
tlen = 0;
m->m_data += IF_MAXLINKHDR;
*mtod(m, struct tcpiphdr *) = *ti;
ti = mtod(m, struct tcpiphdr *);
switch (af) {
case AF_INET:
ti->ti.ti_i4.ih_x1 = 0;
break;
case AF_INET6:
ti->ti.ti_i6.ih_x1 = 0;
break;
default:
g_assert_not_reached();
}
flags = TH_ACK;
} else {
/*
* ti points into m so the next line is just making
* the mbuf point to ti
*/
m->m_data = (char *)ti;
m->m_len = sizeof(struct tcpiphdr);
tlen = 0;
#define xchg(a, b, type) \
{ \
type t; \
t = a; \
a = b; \
b = t; \
}
switch (af) {
case AF_INET:
xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, uint32_t);
xchg(ti->ti_dport, ti->ti_sport, uint16_t);
break;
case AF_INET6:
xchg(ti->ti_dst6, ti->ti_src6, struct in6_addr);
xchg(ti->ti_dport, ti->ti_sport, uint16_t);
break;
default:
g_assert_not_reached();
}
#undef xchg
}
ti->ti_len = htons((uint16_t)(sizeof(struct tcphdr) + tlen));
tlen += sizeof(struct tcpiphdr);
m->m_len = tlen;
ti->ti_mbuf = NULL;
ti->ti_x0 = 0;
ti->ti_seq = htonl(seq);
ti->ti_ack = htonl(ack);
ti->ti_x2 = 0;
ti->ti_off = sizeof(struct tcphdr) >> 2;
ti->ti_flags = flags;
if (tp)
ti->ti_win = htons((uint16_t)(win >> tp->rcv_scale));
else
ti->ti_win = htons((uint16_t)win);
ti->ti_urp = 0;
ti->ti_sum = 0;
ti->ti_sum = cksum(m, tlen);
struct tcpiphdr tcpiph_save = *(mtod(m, struct tcpiphdr *));
struct ip *ip;
struct ip6 *ip6;
switch (af) {
case AF_INET:
m->m_data +=
sizeof(struct tcpiphdr) - sizeof(struct tcphdr) - sizeof(struct ip);
m->m_len -=
sizeof(struct tcpiphdr) - sizeof(struct tcphdr) - sizeof(struct ip);
ip = mtod(m, struct ip *);
ip->ip_len = m->m_len;
ip->ip_dst = tcpiph_save.ti_dst;
ip->ip_src = tcpiph_save.ti_src;
ip->ip_p = tcpiph_save.ti_pr;
if (flags & TH_RST) {
ip->ip_ttl = MAXTTL;
} else {
ip->ip_ttl = IPDEFTTL;
}
ip_output(NULL, m);
break;
case AF_INET6:
m->m_data += sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
sizeof(struct ip6);
m->m_len -= sizeof(struct tcpiphdr) - sizeof(struct tcphdr) -
sizeof(struct ip6);
ip6 = mtod(m, struct ip6 *);
ip6->ip_pl = tcpiph_save.ti_len;
ip6->ip_dst = tcpiph_save.ti_dst6;
ip6->ip_src = tcpiph_save.ti_src6;
ip6->ip_nh = tcpiph_save.ti_nh6;
ip6_output(NULL, m, 0);
break;
default:
g_assert_not_reached();
}
}
/*
* Create a new TCP control block, making an
* empty reassembly queue and hooking it to the argument
* protocol control block.
*/
struct tcpcb *tcp_newtcpcb(struct socket *so)
{
register struct tcpcb *tp;
tp = g_new0(struct tcpcb, 1);
tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp;
/*
* 40: length of IPv4 header (20) + TCP header (20)
* 60: length of IPv6 header (40) + TCP header (20)
*/
tp->t_maxseg =
MIN(so->slirp->if_mtu - ((so->so_ffamily == AF_INET) ? 40 : 60),
TCP_MAXSEG_MAX);
tp->t_flags = TCP_DO_RFC1323 ? (TF_REQ_SCALE | TF_REQ_TSTMP) : 0;
tp->t_socket = so;
/*
* Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
* rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
* reasonable initial retransmit time.
*/
tp->t_srtt = TCPTV_SRTTBASE;
tp->t_rttvar = TCPTV_SRTTDFLT << 2;
tp->t_rttmin = TCPTV_MIN;
TCPT_RANGESET(tp->t_rxtcur,
((TCPTV_SRTTBASE >> 2) + (TCPTV_SRTTDFLT << 2)) >> 1,
TCPTV_MIN, TCPTV_REXMTMAX);
tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->t_state = TCPS_CLOSED;
so->so_tcpcb = tp;
return (tp);
}
/*
* Drop a TCP connection, reporting
* the specified error. If connection is synchronized,
* then send a RST to peer.
*/
struct tcpcb *tcp_drop(struct tcpcb *tp, int err)
{
DEBUG_CALL("tcp_drop");
DEBUG_ARG("tp = %p", tp);
DEBUG_ARG("errno = %d", errno);
if (TCPS_HAVERCVDSYN(tp->t_state)) {
tp->t_state = TCPS_CLOSED;
tcp_output(tp);
}
return (tcp_close(tp));
}
/*
* Close a TCP control block:
* discard all space held by the tcp
* discard internet protocol block
* wake up any sleepers
*/
struct tcpcb *tcp_close(struct tcpcb *tp)
{
register struct tcpiphdr *t;
struct socket *so = tp->t_socket;
Slirp *slirp = so->slirp;
register struct mbuf *m;
DEBUG_CALL("tcp_close");
DEBUG_ARG("tp = %p", tp);
/* free the reassembly queue, if any */
t = tcpfrag_list_first(tp);
while (!tcpfrag_list_end(t, tp)) {
t = tcpiphdr_next(t);
m = tcpiphdr_prev(t)->ti_mbuf;
remque(tcpiphdr2qlink(tcpiphdr_prev(t)));
m_free(m);
}
g_free(tp);
so->so_tcpcb = NULL;
/* clobber input socket cache if we're closing the cached connection */
if (so == slirp->tcp_last_so)
slirp->tcp_last_so = &slirp->tcb;
so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
closesocket(so->s);
sbfree(&so->so_rcv);
sbfree(&so->so_snd);
sofree(so);
return ((struct tcpcb *)0);
}
/*
* TCP protocol interface to socket abstraction.
*/
/*
* User issued close, and wish to trail through shutdown states:
* if never received SYN, just forget it. If got a SYN from peer,
* but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
* If already got a FIN from peer, then almost done; go to LAST_ACK
* state. In all other cases, have already sent FIN to peer (e.g.
* after PRU_SHUTDOWN), and just have to play tedious game waiting
* for peer to send FIN or not respond to keep-alives, etc.
* We can let the user exit from the close as soon as the FIN is acked.
*/
void tcp_sockclosed(struct tcpcb *tp)
{
DEBUG_CALL("tcp_sockclosed");
DEBUG_ARG("tp = %p", tp);
if (!tp) {
return;
}
switch (tp->t_state) {
case TCPS_CLOSED:
case TCPS_LISTEN:
case TCPS_SYN_SENT:
tp->t_state = TCPS_CLOSED;
tcp_close(tp);
return;
case TCPS_SYN_RECEIVED:
case TCPS_ESTABLISHED:
tp->t_state = TCPS_FIN_WAIT_1;
break;
case TCPS_CLOSE_WAIT:
tp->t_state = TCPS_LAST_ACK;
break;
}
tcp_output(tp);
}
/*
* Connect to a host on the Internet
* Called by tcp_input
* Only do a connect, the tcp fields will be set in tcp_input
* return 0 if there's a result of the connect,
* else return -1 means we're still connecting
* The return value is almost always -1 since the socket is
* nonblocking. Connect returns after the SYN is sent, and does
* not wait for ACK+SYN.
*/
int tcp_fconnect(struct socket *so, unsigned short af)
{
int ret = 0;
DEBUG_CALL("tcp_fconnect");
DEBUG_ARG("so = %p", so);
ret = so->s = slirp_socket(af, SOCK_STREAM, 0);
if (ret >= 0) {
ret = slirp_bind_outbound(so, af);
if (ret < 0) {
// bind failed - close socket
closesocket(so->s);
so->s = -1;
return (ret);
}
}
if (ret >= 0) {
int opt, s = so->s;
struct sockaddr_storage addr;
slirp_set_nonblock(s);
so->slirp->cb->register_poll_fd(s, so->slirp->opaque);
slirp_socket_set_fast_reuse(s);
opt = 1;
setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
opt = 1;
setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(opt));
addr = so->fhost.ss;
DEBUG_CALL(" connect()ing");
if (sotranslate_out(so, &addr) < 0) {
return -1;
}
/* We don't care what port we get */
ret = connect(s, (struct sockaddr *)&addr, sockaddr_size(&addr));
/*
* If it's not in progress, it failed, so we just return 0,
* without clearing SS_NOFDREF
*/
soisfconnecting(so);
}
return (ret);
}
/*
* Accept the socket and connect to the local-host
*
* We have a problem. The correct thing to do would be
* to first connect to the local-host, and only if the
* connection is accepted, then do an accept() here.
* But, a) we need to know who's trying to connect
* to the socket to be able to SYN the local-host, and
* b) we are already connected to the foreign host by
* the time it gets to accept(), so... We simply accept
* here and SYN the local-host.
*/
void tcp_connect(struct socket *inso)
{
Slirp *slirp = inso->slirp;
struct socket *so;
struct sockaddr_storage addr;
socklen_t addrlen;
struct tcpcb *tp;
int s, opt, ret;
/* AF_INET6 addresses are bigger than AF_INET, so this is big enough. */
char addrstr[INET6_ADDRSTRLEN];
char portstr[6];
DEBUG_CALL("tcp_connect");
DEBUG_ARG("inso = %p", inso);
switch (inso->lhost.ss.ss_family) {
case AF_INET:
addrlen = sizeof(struct sockaddr_in);
break;
case AF_INET6:
addrlen = sizeof(struct sockaddr_in6);
break;
default:
g_assert_not_reached();
}
ret = getnameinfo((const struct sockaddr *) &inso->lhost.ss, addrlen, addrstr, sizeof(addrstr), portstr, sizeof(portstr), NI_NUMERICHOST|NI_NUMERICSERV);
g_assert(ret == 0);
DEBUG_ARG("ip = [%s]:%s", addrstr, portstr);
DEBUG_ARG("so_state = 0x%x", inso->so_state);
/* Perform lazy guest IP address resolution if needed. */
if (inso->so_state & SS_HOSTFWD) {
/*
* We can only reject the connection request by accepting it and
* then immediately closing it. Note that SS_FACCEPTONCE sockets can't
* get here.
*/
if (soassign_guest_addr_if_needed(inso) < 0) {
/*
* Guest address isn't available yet. We could either try to defer
* completing this connection request until the guest address is
* available, or punt. It's easier to punt. Otherwise we need to
* complicate the mechanism by which we're called to defer calling
* us again until the guest address is available.
*/
DEBUG_MISC(" guest address not available yet");
addrlen = sizeof(addr);
s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
if (s >= 0) {
close(s);
}
return;
}
}
/*
* If it's an SS_ACCEPTONCE socket, no need to socreate()
* another socket, just use the accept() socket.
*/
if (inso->so_state & SS_FACCEPTONCE) {
/* FACCEPTONCE already have a tcpcb */
so = inso;
} else {
so = socreate(slirp, IPPROTO_TCP);
tcp_attach(so);
so->lhost = inso->lhost;
so->so_ffamily = inso->so_ffamily;
}
tcp_mss(sototcpcb(so), 0);
addrlen = sizeof(addr);
s = accept(inso->s, (struct sockaddr *)&addr, &addrlen);
if (s < 0) {
tcp_close(sototcpcb(so)); /* This will sofree() as well */
return;
}
slirp_set_nonblock(s);
so->slirp->cb->register_poll_fd(s, so->slirp->opaque);
slirp_socket_set_fast_reuse(s);
opt = 1;
setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
slirp_socket_set_nodelay(s);
so->fhost.ss = addr;
sotranslate_accept(so);
/* Close the accept() socket, set right state */
if (inso->so_state & SS_FACCEPTONCE) {
/* If we only accept once, close the accept() socket */
so->slirp->cb->unregister_poll_fd(so->s, so->slirp->opaque);
closesocket(so->s);
/* Don't select it yet, even though we have an FD */
/* if it's not FACCEPTONCE, it's already NOFDREF */
so->so_state = SS_NOFDREF;
}
so->s = s;
so->so_state |= SS_INCOMING;
so->so_iptos = tcp_tos(so);
tp = sototcpcb(so);
tcp_template(tp);
tp->t_state = TCPS_SYN_SENT;
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
tp->iss = slirp->tcp_iss;
slirp->tcp_iss += TCP_ISSINCR / 2;
tcp_sendseqinit(tp);
tcp_output(tp);
}
/*
* Attach a TCPCB to a socket.
*/
void tcp_attach(struct socket *so)
{
so->so_tcpcb = tcp_newtcpcb(so);
insque(so, &so->slirp->tcb);
}
/*
* Set the socket's type of service field
*/
static const struct tos_t tcptos[] = {
{ 0, 20, IPTOS_THROUGHPUT, 0 }, /* ftp data */
{ 21, 21, IPTOS_LOWDELAY, EMU_FTP }, /* ftp control */
{ 0, 23, IPTOS_LOWDELAY, 0 }, /* telnet */
{ 0, 80, IPTOS_THROUGHPUT, 0 }, /* WWW */
{ 0, 513, IPTOS_LOWDELAY, EMU_RLOGIN | EMU_NOCONNECT }, /* rlogin */
{ 0, 544, IPTOS_LOWDELAY, EMU_KSH }, /* kshell */
{ 0, 543, IPTOS_LOWDELAY, 0 }, /* klogin */
{ 0, 6667, IPTOS_THROUGHPUT, EMU_IRC }, /* IRC */
{ 0, 6668, IPTOS_THROUGHPUT, EMU_IRC }, /* IRC undernet */
{ 0, 7070, IPTOS_LOWDELAY, EMU_REALAUDIO }, /* RealAudio control */
{ 0, 113, IPTOS_LOWDELAY, EMU_IDENT }, /* identd protocol */
{ 0, 0, 0, 0 }
};
/*
* Return TOS according to the above table
*/
uint8_t tcp_tos(struct socket *so)
{
int i = 0;
while (tcptos[i].tos) {
if ((tcptos[i].fport && (ntohs(so->so_fport) == tcptos[i].fport)) ||
(tcptos[i].lport && (ntohs(so->so_lport) == tcptos[i].lport))) {
if (so->slirp->enable_emu)
so->so_emu = tcptos[i].emu;
return tcptos[i].tos;
}
i++;
}
return 0;
}
/*
* Emulate programs that try and connect to us
* This includes ftp (the data connection is
* initiated by the server) and IRC (DCC CHAT and
* DCC SEND) for now
*
* NOTE: It's possible to crash SLiRP by sending it
* unstandard strings to emulate... if this is a problem,
* more checks are needed here
*
* XXX Assumes the whole command came in one packet
* XXX If there is more than one command in the packet, the others may
* be truncated.
* XXX If the command is too long, it may be truncated.
*
* XXX Some ftp clients will have their TOS set to
* LOWDELAY and so Nagel will kick in. Because of this,
* we'll get the first letter, followed by the rest, so
* we simply scan for ORT instead of PORT...
* DCC doesn't have this problem because there's other stuff
* in the packet before the DCC command.
*
* Return 1 if the mbuf m is still valid and should be
* sbappend()ed
*
* NOTE: if you return 0 you MUST m_free() the mbuf!
*/
int tcp_emu(struct socket *so, struct mbuf *m)
{
Slirp *slirp = so->slirp;
unsigned n1, n2, n3, n4, n5, n6;
char buff[257];
uint32_t laddr;
unsigned lport;
char *bptr;
DEBUG_CALL("tcp_emu");
DEBUG_ARG("so = %p", so);
DEBUG_ARG("m = %p", m);
switch (so->so_emu) {
int x, i;
/* TODO: IPv6 */
case EMU_IDENT:
/*
* Identification protocol as per rfc-1413
*/
{
struct socket *tmpso;
struct sockaddr_in addr;
socklen_t addrlen = sizeof(struct sockaddr_in);
char *eol = g_strstr_len(m->m_data, m->m_len, "\r\n");
if (!eol) {
return 1;
}
*eol = '\0';
if (sscanf(m->m_data, "%u%*[ ,]%u", &n1, &n2) == 2) {
HTONS(n1);
HTONS(n2);
/* n2 is the one on our host */
for (tmpso = slirp->tcb.so_next; tmpso != &slirp->tcb;
tmpso = tmpso->so_next) {
if (tmpso->so_laddr.s_addr == so->so_laddr.s_addr &&
tmpso->so_lport == n2 &&
tmpso->so_faddr.s_addr == so->so_faddr.s_addr &&
tmpso->so_fport == n1) {
if (getsockname(tmpso->s, (struct sockaddr *)&addr,
&addrlen) == 0)
n2 = addr.sin_port;
break;
}
}
NTOHS(n1);
NTOHS(n2);
m_inc(m, g_snprintf(NULL, 0, "%d,%d\r\n", n1, n2) + 1);
m->m_len = slirp_fmt(m->m_data, M_ROOM(m), "%d,%d\r\n", n1, n2);
} else {
*eol = '\r';
}
return 1;
}
case EMU_FTP: /* ftp */
m_inc(m, m->m_len + 1);
*(m->m_data + m->m_len) = 0; /* NUL terminate for strstr */
if ((bptr = (char *)strstr(m->m_data, "ORT")) != NULL) {
/*
* Need to emulate the PORT command
*/
x = sscanf(bptr, "ORT %u,%u,%u,%u,%u,%u\r\n%256[^\177]", &n1, &n2,
&n3, &n4, &n5, &n6, buff);
if (x < 6)
return 1;
laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
lport = htons((n5 << 8) | (n6));
if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr, lport,
SS_FACCEPTONCE)) == NULL) {
return 1;
}
n6 = ntohs(so->so_fport);
n5 = (n6 >> 8) & 0xff;
n6 &= 0xff;
laddr = ntohl(so->so_faddr.s_addr);
n1 = ((laddr >> 24) & 0xff);
n2 = ((laddr >> 16) & 0xff);
n3 = ((laddr >> 8) & 0xff);
n4 = (laddr & 0xff);
m->m_len = bptr - m->m_data; /* Adjust length */
m->m_len += slirp_fmt(bptr, M_FREEROOM(m),
"ORT %d,%d,%d,%d,%d,%d\r\n%s",
n1, n2, n3, n4, n5, n6, x == 7 ? buff : "");
return 1;
} else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
/*
* Need to emulate the PASV response
*/
x = sscanf(
bptr,
"27 Entering Passive Mode (%u,%u,%u,%u,%u,%u)\r\n%256[^\177]",
&n1, &n2, &n3, &n4, &n5, &n6, buff);
if (x < 6)
return 1;
laddr = htonl((n1 << 24) | (n2 << 16) | (n3 << 8) | (n4));
lport = htons((n5 << 8) | (n6));
if ((so = tcp_listen(slirp, INADDR_ANY, 0, laddr, lport,
SS_FACCEPTONCE)) == NULL) {
return 1;
}
n6 = ntohs(so->so_fport);
n5 = (n6 >> 8) & 0xff;
n6 &= 0xff;
laddr = ntohl(so->so_faddr.s_addr);
n1 = ((laddr >> 24) & 0xff);
n2 = ((laddr >> 16) & 0xff);
n3 = ((laddr >> 8) & 0xff);
n4 = (laddr & 0xff);
m->m_len = bptr - m->m_data; /* Adjust length */
m->m_len += slirp_fmt(bptr, M_FREEROOM(m),
"27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
n1, n2, n3, n4, n5, n6, x == 7 ? buff : "");
return 1;
}
return 1;
case EMU_KSH:
/*
* The kshell (Kerberos rsh) and shell services both pass
* a local port port number to carry signals to the server
* and stderr to the client. It is passed at the beginning
* of the connection as a NUL-terminated decimal ASCII string.
*/
so->so_emu = 0;
for (lport = 0, i = 0; i < m->m_len - 1; ++i) {
if (m->m_data[i] < '0' || m->m_data[i] > '9')
return 1; /* invalid number */
lport *= 10;
lport += m->m_data[i] - '0';
}
if (m->m_data[m->m_len - 1] == '\0' && lport != 0 &&
(so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
htons(lport), SS_FACCEPTONCE)) != NULL)
m->m_len = slirp_fmt0(m->m_data, M_ROOM(m),
"%d", ntohs(so->so_fport));
return 1;
case EMU_IRC:
/*
* Need to emulate DCC CHAT, DCC SEND and DCC MOVE
*/
m_inc(m, m->m_len + 1);
*(m->m_data + m->m_len) = 0; /* NULL terminate the string for strstr */
if ((bptr = (char *)strstr(m->m_data, "DCC")) == NULL)
return 1;
/* The %256s is for the broken mIRC */
if (sscanf(bptr, "DCC CHAT %256s %u %u", buff, &laddr, &lport) == 3) {
if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
htons(lport), SS_FACCEPTONCE)) == NULL) {
return 1;
}
m->m_len = bptr - m->m_data; /* Adjust length */
m->m_len += slirp_fmt(bptr, M_FREEROOM(m),
"DCC CHAT chat %lu %u%c\n",
(unsigned long)ntohl(so->so_faddr.s_addr),
ntohs(so->so_fport), 1);
} else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport,
&n1) == 4) {
if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
htons(lport), SS_FACCEPTONCE)) == NULL) {
return 1;
}
m->m_len = bptr - m->m_data; /* Adjust length */
m->m_len += slirp_fmt(bptr, M_FREEROOM(m),
"DCC SEND %s %lu %u %u%c\n", buff,
(unsigned long)ntohl(so->so_faddr.s_addr),
ntohs(so->so_fport), n1, 1);
} else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport,
&n1) == 4) {
if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
htons(lport), SS_FACCEPTONCE)) == NULL) {
return 1;
}
m->m_len = bptr - m->m_data; /* Adjust length */
m->m_len += slirp_fmt(bptr, M_FREEROOM(m),
"DCC MOVE %s %lu %u %u%c\n", buff,
(unsigned long)ntohl(so->so_faddr.s_addr),
ntohs(so->so_fport), n1, 1);
}
return 1;
case EMU_REALAUDIO:
/*
* RealAudio emulation - JP. We must try to parse the incoming
* data and try to find the two characters that contain the
* port number. Then we redirect an udp port and replace the
* number with the real port we got.
*
* The 1.0 beta versions of the player are not supported
* any more.
*
* A typical packet for player version 1.0 (release version):
*
* 0000:50 4E 41 00 05
* 0000:00 01 00 02 1B D7 00 00 67 E6 6C DC 63 00 12 50 ........g.l.c..P
* 0010:4E 43 4C 49 45 4E 54 20 31 30 31 20 41 4C 50 48 NCLIENT 101 ALPH
* 0020:41 6C 00 00 52 00 17 72 61 66 69 6C 65 73 2F 76 Al..R..rafiles/v
* 0030:6F 61 2F 65 6E 67 6C 69 73 68 5F 2E 72 61 79 42 oa/english_.rayB
*
* Now the port number 0x1BD7 is found at offset 0x04 of the
* Now the port number 0x1BD7 is found at offset 0x04 of the
* second packet. This time we received five bytes first and
* then the rest. You never know how many bytes you get.
*
* A typical packet for player version 2.0 (beta):
*
* 0000:50 4E 41 00 06 00 02 00 00 00 01 00 02 1B C1 00 PNA.............
* 0010:00 67 75 78 F5 63 00 0A 57 69 6E 32 2E 30 2E 30 .gux.c..Win2.0.0
* 0020:2E 35 6C 00 00 52 00 1C 72 61 66 69 6C 65 73 2F .5l..R..rafiles/
* 0030:77 65 62 73 69 74 65 2F 32 30 72 65 6C 65 61 73 website/20releas
* 0040:65 2E 72 61 79 53 00 00 06 36 42 e.rayS...6B
*
* Port number 0x1BC1 is found at offset 0x0d.
*
* This is just a horrible switch statement. Variable ra tells
* us where we're going.
*/
bptr = m->m_data;
while (bptr < m->m_data + m->m_len) {
uint16_t p;
static int ra = 0;
char ra_tbl[4];
ra_tbl[0] = 0x50;
ra_tbl[1] = 0x4e;
ra_tbl[2] = 0x41;
ra_tbl[3] = 0;
switch (ra) {
case 0:
case 2:
case 3:
if (*bptr++ != ra_tbl[ra]) {
ra = 0;
continue;
}
break;
case 1:
/*
* We may get 0x50 several times, ignore them
*/
if (*bptr == 0x50) {
ra = 1;
bptr++;
continue;
} else if (*bptr++ != ra_tbl[ra]) {
ra = 0;
continue;
}
break;
case 4:
/*
* skip version number
*/
bptr++;
break;
case 5:
if (bptr == m->m_data + m->m_len - 1)
return 1; /* We need two bytes */
/*
* The difference between versions 1.0 and
* 2.0 is here. For future versions of
* the player this may need to be modified.
*/
if (*(bptr + 1) == 0x02)
bptr += 8;
else
bptr += 4;
break;
case 6:
/* This is the field containing the port
* number that RA-player is listening to.
*/
if (bptr == m->m_data + m->m_len - 1)
return 1; /* We need two bytes */
lport = (((uint8_t *)bptr)[0] << 8) + ((uint8_t *)bptr)[1];
if (lport < 6970)
lport += 256; /* don't know why */
if (lport < 6970 || lport > 7170)
return 1; /* failed */
/* try to get udp port between 6970 - 7170 */
for (p = 6970; p < 7071; p++) {
if (udp_listen(slirp, INADDR_ANY, htons(p),
so->so_laddr.s_addr, htons(lport),
SS_FACCEPTONCE)) {
break;
}
}
if (p == 7071)
p = 0;
*(uint8_t *)bptr++ = (p >> 8) & 0xff;
*(uint8_t *)bptr = p & 0xff;
ra = 0;
return 1; /* port redirected, we're done */
break;
default:
ra = 0;
}
ra++;
}
return 1;
default:
/* Ooops, not emulated, won't call tcp_emu again */
so->so_emu = 0;
return 1;
}
}
/*
* Do misc. config of SLiRP while its running.
* Return 0 if this connections is to be closed, 1 otherwise,
* return 2 if this is a command-line connection
*/
int tcp_ctl(struct socket *so)
{
Slirp *slirp = so->slirp;
struct sbuf *sb = &so->so_snd;
struct gfwd_list *ex_ptr;
DEBUG_CALL("tcp_ctl");
DEBUG_ARG("so = %p", so);
/* TODO: IPv6 */
if (so->so_faddr.s_addr != slirp->vhost_addr.s_addr) {
/* Check if it's pty_exec */
for (ex_ptr = slirp->guestfwd_list; ex_ptr; ex_ptr = ex_ptr->ex_next) {
if (ex_ptr->ex_fport == so->so_fport &&
so->so_faddr.s_addr == ex_ptr->ex_addr.s_addr) {
if (ex_ptr->write_cb) {
so->s = -1;
so->guestfwd = ex_ptr;
return 1;
}
DEBUG_MISC(" executing %s", ex_ptr->ex_exec);
if (ex_ptr->ex_unix)
return open_unix(so, ex_ptr->ex_unix);
else
return fork_exec(so, ex_ptr->ex_exec);
}
}
}
sb->sb_cc = slirp_fmt(sb->sb_wptr, sb->sb_datalen - (sb->sb_wptr - sb->sb_data),
"Error: No application configured.\r\n");
sb->sb_wptr += sb->sb_cc;
return 0;
}