slirp: move sources to src/ subdirectory

Prepare for making slirp/ a standalone project.

Remove some useless includes while at it.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190212162524.31504-5-marcandre.lureau@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

1 files changed, 989 insertions, 0 deletions

diff --git a/slirp/src/tcp_subr.c b/slirp/src/tcp_subr.c
new file mode 100644
index 0000000000..1db59caa89
--- /dev/null
+++ b/slirp/src/tcp_subr.c
@@ -0,0 +1,989 @@
+/*
+ * 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.
+ *
+ * Please read the file COPYRIGHT for the
+ * terms and conditions of the copyright.
+ */
+
+#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 = (struct tcpcb *)malloc(sizeof(*tp));
+	if (tp == NULL)
+		return ((struct tcpcb *)0);
+
+	memset((char *) tp, 0, sizeof(struct tcpcb));
+	tp->seg_next = tp->seg_prev = (struct tcpiphdr*)tp;
+	tp->t_maxseg = (so->so_ffamily == AF_INET) ? TCP_MSS : TCP6_MSS;
+
+	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;
+		(void) 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);
+	}
+	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;
+		tp = tcp_close(tp);
+		break;
+
+	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) {
+    int opt, s=so->s;
+    struct sockaddr_storage addr;
+
+    slirp_set_nonblock(s);
+    so->slirp->cb->register_poll_fd(so->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");
+    sotranslate_out(so, &addr);
+
+    /* 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 = sizeof(struct sockaddr_storage);
+    struct tcpcb *tp;
+    int s, opt;
+
+    DEBUG_CALL("tcp_connect");
+    DEBUG_ARG("inso = %p", inso);
+
+    /*
+     * 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);
+        if (tcp_attach(so) < 0) {
+            g_free(so); /* NOT sofree */
+            return;
+        }
+        so->lhost = inso->lhost;
+        so->so_ffamily = inso->so_ffamily;
+    }
+
+    tcp_mss(sototcpcb(so), 0);
+
+    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(so->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.
+ */
+int
+tcp_attach(struct socket *so)
+{
+	if ((so->so_tcpcb = tcp_newtcpcb(so)) == NULL)
+	   return -1;
+
+	insque(so, &so->slirp->tcb);
+
+	return 0;
+}
+
+/*
+ * 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}
+};
+
+static struct emu_t *tcpemu = NULL;
+
+/*
+ * Return TOS according to the above table
+ */
+uint8_t
+tcp_tos(struct socket *so)
+{
+	int i = 0;
+	struct emu_t *emup;
+
+	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))) {
+			so->so_emu = tcptos[i].emu;
+			return tcptos[i].tos;
+		}
+		i++;
+	}
+
+	/* Nope, lets see if there's a user-added one */
+	for (emup = tcpemu; emup; emup = emup->next) {
+		if ((emup->fport && (ntohs(so->so_fport) == emup->fport)) ||
+		    (emup->lport && (ntohs(so->so_lport) == emup->lport))) {
+			so->so_emu = emup->emu;
+			return emup->tos;
+		}
+	}
+
+	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 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);
+			struct sbuf *so_rcv = &so->so_rcv;
+
+			if (m->m_len > so_rcv->sb_datalen
+					- (so_rcv->sb_wptr - so_rcv->sb_data)) {
+			    return 1;
+			}
+
+			memcpy(so_rcv->sb_wptr, m->m_data, m->m_len);
+			so_rcv->sb_wptr += m->m_len;
+			so_rcv->sb_rptr += m->m_len;
+			m->m_data[m->m_len] = 0; /* NULL terminate */
+			if (strchr(m->m_data, '\r') || strchr(m->m_data, '\n')) {
+				if (sscanf(so_rcv->sb_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);
+					so_rcv->sb_cc = snprintf(so_rcv->sb_data,
+								 so_rcv->sb_datalen,
+								 "%d,%d\r\n", n1, n2);
+					so_rcv->sb_rptr = so_rcv->sb_data;
+					so_rcv->sb_wptr = so_rcv->sb_data + so_rcv->sb_cc;
+				}
+			}
+			m_free(m);
+			return 0;
+		}
+
+        case EMU_FTP: /* ftp */
+                *(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 += snprintf(bptr, m->m_size - m->m_len,
+                                             "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 += snprintf(bptr, m->m_size - m->m_len,
+                                             "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 = snprintf(m->m_data, m->m_size, "%d",
+                                        ntohs(so->so_fport)) + 1;
+		return 1;
+
+	 case EMU_IRC:
+		/*
+		 * Need to emulate DCC CHAT, DCC SEND and DCC MOVE
+		 */
+		*(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 += snprintf(bptr, m->m_size,
+                                             "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 += snprintf(bptr, m->m_size,
+                                             "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 += snprintf(bptr, m->m_size,
+                                             "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:
+				/*
+				 * 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.
+				 */
+				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);
+                return fork_exec(so, ex_ptr->ex_exec);
+            }
+        }
+    }
+    sb->sb_cc =
+        snprintf(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;
+}