tinc: implement experimental mash peer to peer VPN from http://www.tinc-vpn.org/

3 files changed, 1782 insertions, 0 deletions

diff --git a/sys/man/8/tinc b/sys/man/8/tinc
new file mode 100644
index 000000000..18163e88a
--- /dev/null
+++ b/sys/man/8/tinc
@@ -0,0 +1,119 @@
+.TH TINC 8
+.SH NAME
+tinc - mash peer to peer VPN
+.SH SYNOPSIS
+.B ip/tinc
+[
+.B -d
+] [
+.B -p
+.I maxprocs
+] [
+.B -x
+.I inside
+] [
+.B -o
+.I outside
+] [
+.B -c
+.I confdir
+] [
+.B -n
+.I myname
+]
+.I localip
+.I localmask
+[
+.I hosts...
+]
+.SH DESCRIPTION
+Tinc implements the mash peer to peer VPN protocol from
+.I https://www.tinc-vpn.org/
+as of version 1.0.32. Within a tinc VPN one can reach all
+the subnets of all hosts within the network even when not
+directly connected to the owning host of the subnet.
+.PP
+Each host that is directly connected to us has its own hostfile under
+.IR confdir /hosts/ hostname
+containing its public address, owned subnets, options and RSA public key.
+The hostfile format is the same as the original tinc implementation.
+The
+.I confdir
+is specified with the
+.B -c
+option or defaults to the current working directory.
+Other hosts might exist behind these directly connected nodes but
+this information is distributed automatically within the protocol.
+.PP
+On startup,
+.I tinc
+creates an ip interface with the address
+.I localip
+and network mask
+.I localmask
+on the
+.I inside
+ip stack (specified with
+.B -x
+option) and starts listening for incoming connections on the
+.I outside
+ip stack (specified with the
+.B -o
+option). When optional
+.I hosts
+are specified on the command line, then it will also do outgoing connections
+using the
+.I outside
+ip stack. The
+.I localmask
+usually is a supernet of all the subnets within the VPN. Our own hostname
+.I myhost
+can be specified with
+.B -n
+option or is asssumed to be the
+.I sysname
+when not specified.
+This hosts RSA private key needs to be present in factotum and tagged with
+.BR "service=tinc"
+and
+.BI "host=" myhost .
+.PP
+The options:
+.TP
+.B -d
+Enable debug outout and do not fork to the background.
+.TP
+.B -p
+Limit the number of client processes to
+.IR  maxprocs .
+.TP
+.B -x
+Specifies the
+.I inside
+and
+.I outside
+network stack directory where the tinc ip interface it bound. Defaults to
+.BR /net .
+.TP
+.B -o
+Specifies the
+.I outside
+network stack directory where incoming and outgoing tinc connections
+are made. Defaults to
+.BR inside .
+.TP
+.B -c
+Specifies the configuration directory
+.I confdir
+for the VPN.
+.TP
+.B -n
+Sets our hostname to
+.IR myhost .
+.SH "SEE ALSO"
+.IR rsa (8),
+.IR ip (3)
+.br
+.I https://www.tinc-vpn.org/documentation/
+.SH SOURCE
+.B /sys/src/cmd/ip/tinc.c
diff --git a/sys/src/cmd/ip/mkfile b/sys/src/cmd/ip/mkfile
index 900bb17f7..702a2e01e 100644
--- a/sys/src/cmd/ip/mkfile
+++ b/sys/src/cmd/ip/mkfile
@@ -21,6 +21,7 @@ TARG = 	6in4\
 	telnetd\
 	tftpd\
 	tftpfs\
+	tinc\
 	traceroute\
 	torrent\
 	udpecho\
diff --git a/sys/src/cmd/ip/tinc.c b/sys/src/cmd/ip/tinc.c
new file mode 100644
index 000000000..31ac6e380
--- /dev/null
+++ b/sys/src/cmd/ip/tinc.c
@@ -0,0 +1,1662 @@
+#include <u.h>
+#include <libc.h>
+#include <mp.h>
+#include <libsec.h>
+#include <auth.h>
+#include <ip.h>
+
+enum {
+	OptIndirect	= 1,
+	OptTcpOnly	= 3,
+	OptPmtuDiscov	= 4,
+	OptClampMss	= 8,
+
+	MaxWeight	= 0x7fffffff,
+	AESkeylen	= 256/8,
+	MAClen		= 4,
+
+	Eaddrlen	= 6,
+	EtherType	= 2*Eaddrlen,
+	EtherHdr	= EtherType+2,
+
+	Ip4Hdr		= 20,
+	Ip6Hdr		= 40,
+	UdpHdr		= 8,
+	TcpHdr		= 20,
+
+	/* worst case: UDPv6 over 6in4 over PPPoE */
+	DefPMTU		= 1500-8-Ip4Hdr-Ip6Hdr-UdpHdr-4-AESbsize-MAClen,
+
+	MaxPacket	= 4096,
+
+	/* messages */
+	ID		= 0,
+	META_KEY	= 1,
+	CHALLENGE	= 2,
+	CHAL_REPLY	= 3,
+	ACK		= 4,
+	PING		= 8,
+	PONG		= 9,
+	ADD_SUBNET	= 10,
+	DEL_SUBNET	= 11,
+	ADD_EDGE	= 12,
+	DEL_EDGE	= 13,
+	KEY_CHANGED	= 14,
+	REQ_KEY		= 15,
+	ANS_KEY		= 16,
+	TCP_PACKET	= 17,
+
+	/* openssl crap */
+	EVP_AES256CBC	= 427,
+	EVP_AES256CFB	= 429,
+	EVP_SHA256	= 672,
+};
+
+typedef struct Snet Snet;
+typedef struct Edge Edge;
+typedef struct Ciph Ciph;
+typedef struct Host Host;
+typedef struct Conn Conn;
+
+struct Snet
+{
+	Host	*owner;
+
+	Snet	*next;	/* next subnet on owner */
+	uchar	mask[IPaddrlen];
+	uchar	ip[IPaddrlen];
+	int	prefixlen;
+	int	weight;
+	char	reported;
+	char	deleted;
+};
+
+struct Edge
+{
+	Host	*src;
+	Host	*dst;
+	Edge	*next;	/* next edge on src */
+	Edge	*rev;	/* reverse drection edge */
+
+	uchar	ip[IPaddrlen];
+	int	port;
+
+	int	options;
+	int	weight;
+	char	reported;
+	char	deleted;
+};
+
+struct Ciph
+{
+	void	(*crypt)(uchar*, int, AESstate*);
+	uint	seq;
+	uchar	key[AESkeylen+AESbsize];
+	AESstate cs[1];
+	Lock;
+};
+
+struct Host
+{
+	Host	*next;
+	char	*name;
+	char	*addr;
+
+	Conn	*conn;
+	Host	*from;
+	Edge	*link;
+
+	Snet	*snet;
+
+	uchar	ip[IPaddrlen];
+	int	port;
+
+	int	connected;
+	int	options;
+	int	pmtu;
+	int	udpfd;
+
+	uvlong	ooo;	/* out of order replay window */
+	Ciph	cin[1];
+	Ciph	cout[1];
+
+	RSApub	*rsapub;
+};
+
+struct Conn
+{
+	Host	*host;
+	Edge	*edge;
+
+	int	fd;
+	int	port;
+	uchar	ip[IPaddrlen];
+
+	vlong	pingtime;
+
+	QLock	sendlk;
+
+	Ciph	cin[1];
+	Ciph	cout[1];
+
+	char	*rp;
+	char	*wp;
+	char	buf[MaxPacket+16];
+};
+
+QLock	hostslk;
+Host	*hosts;
+
+Edge	**edges;
+int	nedges;
+Snet	**snet;
+int	nsnet;
+
+int	debug;
+int	maxprocs = 100;
+
+char	*confdir = ".";
+char	*myname = nil;
+Host	*myhost = nil;
+
+Conn	*bcast = (void*)-1;
+Conn	*lconn = nil;
+RWLock	netlk;
+
+char	*outside = "/net";
+char	*inside = "/net";
+int	ipifn = 0;
+int	ipcfd = -1;
+int	ipdfd = -1;
+uchar	localip[IPaddrlen];
+uchar	localmask[IPaddrlen];
+
+void	deledge(Edge*);
+void	delsubnet(Snet*);
+void	netrecalc(void);
+
+void	procsetname(char *fmt, ...);
+int	consend(Conn *c, char *fmt, ...);
+void	routepkt(Host *s, uchar *p, int n);
+void	needkey(Host *from);
+void	clearkey(Host *from);
+
+#pragma varargck argpos procsetname 1
+#pragma varargck argpos consend 2
+
+void*
+emalloc(ulong len)
+{
+	void *v = malloc(len);
+	if(v == nil)
+		sysfatal("malloc: %r");
+	setmalloctag(v, getcallerpc(&len));
+	memset(v, 0, len);
+	return v;
+}
+void*
+erealloc(void *v, ulong len)
+{
+	if((v = realloc(v, len)) == nil && len != 0)
+		sysfatal("realloc: %r");
+	setrealloctag(v, getcallerpc(&v));
+	return v;
+}
+char*
+estrdup(char *s)
+{
+	if((s = strdup(s)) == nil)
+		sysfatal("strdup: %r");
+	setmalloctag(s, getcallerpc(&s));
+	return s;
+}
+
+void
+procsetname(char *fmt, ...)
+{
+	int fd, n;
+	char buf[128];
+	va_list arg;
+
+	snprint(buf, sizeof buf, "#p/%d/args", getpid());
+	if((fd = open(buf, OWRITE)) < 0)
+		return;
+	va_start(arg, fmt);
+	n = vsnprint(buf, sizeof buf, fmt, arg);
+	va_end(arg);
+	write(fd, buf, n+1);
+	close(fd);
+}
+
+char*
+fd2dir(int fd, char *dir, int len)
+{
+	char *p;
+
+	*dir = 0;
+	if(fd2path(fd, dir, len) < 0)
+		return nil;
+	p = strrchr(dir, '/');
+	if(p == nil || p == dir)
+		return nil;
+	*p = 0;
+	return dir;
+}
+
+int
+dir2ipport(char *dir, uchar ip[IPaddrlen])
+{
+	NetConnInfo *nci;
+	int port = -1;
+
+	if((nci = getnetconninfo(dir, -1)) == nil)
+		return -1;
+	if(parseip(ip, nci->rsys) != -1)
+		port = atoi(nci->rserv);
+	freenetconninfo(nci);
+	return port;
+}
+
+void
+hangupfd(int fd)
+{
+	char buf[128];
+
+	if(fd < 0 || fd2dir(fd, buf, sizeof(buf)-5) == nil)
+		return;
+	strcat(buf, "/ctl");
+	if((fd = open(buf, OWRITE)) >= 0){
+		hangup(fd);
+		close(fd);
+	}
+}
+
+void
+netlock(Conn *c)
+{
+	if(c != nil) {
+		wlock(&netlk);
+		assert(lconn == nil);
+		lconn = c;
+	} else {
+		rlock(&netlk);
+		assert(lconn == nil);
+	}
+}
+void
+netunlock(Conn *c)
+{
+	if(c != nil){
+		assert(c == lconn);
+		netrecalc();
+		lconn = nil;
+		wunlock(&netlk);
+	}else {
+		assert(lconn == nil);
+		runlock(&netlk);
+	}
+}
+
+int
+edgecmp(Edge *a, Edge *b)
+{
+	int c;
+
+	if((c = a->deleted - b->deleted) != 0)
+		return c;
+	return a->weight - b->weight;
+}
+int
+edgepcmp(void *a, void *b)
+{
+	return edgecmp(*(Edge**)a, *(Edge**)b);
+}
+
+int
+subnetcmp(Snet *a, Snet *b)
+{
+	int c;
+
+	if((c = a->deleted - b->deleted) != 0)
+		return c;
+	if((c = memcmp(b->mask, a->mask, IPaddrlen)) != 0)
+		return c;
+	if((c = memcmp(a->ip, b->ip, IPaddrlen)) != 0)
+		return c;
+	return a->weight - b->weight;
+}
+int
+subnetpcmp(void *a, void *b)
+{
+	return subnetcmp(*(Snet**)a, *(Snet**)b);
+}
+
+Snet*
+lookupnet(uchar ip[IPaddrlen])
+{
+	int i;
+	Snet *t;
+	uchar x[IPaddrlen];
+
+	for(i=0; i<nsnet; i++){
+		t = snet[i];
+		maskip(ip, t->mask, x);
+		if(memcmp(x, t->ip, IPaddrlen) == 0)
+			return t;
+	}
+	return nil;
+}
+
+void
+reportsubnet(Conn *c, Snet *t)
+{
+	if(c == nil || !(t->deleted || t->owner->connected))
+		return;
+	if(c == bcast){
+		Edge *x;
+
+		if(t->deleted != t->reported)
+			return;
+		t->reported = !t->deleted;
+		for(x = myhost->link; x != nil; x = x->next)
+			if(x->dst->conn != lconn && x->dst->from == myhost)
+				reportsubnet(x->dst->conn, t);
+		return;
+	}
+	if(t->owner == c->host)
+		return;
+	if(t->deleted)
+		consend(c, "%d %x %s %I/%d#%d", DEL_SUBNET, rand(),
+			t->owner->name, t->ip, t->prefixlen, t->weight);
+	else
+		consend(c, "%d %x %s %I/%d#%d", ADD_SUBNET, rand(), t->owner->name,
+			t->ip, t->prefixlen, t->weight);
+}
+void
+reportedge(Conn *c, Edge *e)
+{
+	if(c == nil || !(e->deleted || e->src->connected && e->dst->connected))
+		return;
+	if(c == bcast){
+		Edge *x;
+
+		if(e->deleted != e->reported)
+			return;
+		e->reported = !e->deleted;
+		for(x = myhost->link; x != nil; x = x->next)
+			if(x->dst->conn != lconn && x->dst->from == myhost)
+				reportedge(x->dst->conn, e);
+		return;
+	}
+	if(e->src == c->host)
+		return;
+	if(e->deleted){
+		if(e->dst == c->host)
+			return;
+		consend(c, "%d %x %s %s", DEL_EDGE, rand(),
+			e->src->name, e->dst->name);
+	} else
+		consend(c, "%d %x %s %s %s %d %x %d", ADD_EDGE, rand(),
+			e->src->name, e->dst->name,
+			e->dst->addr, e->dst->port, e->dst->options, e->weight);
+}
+
+void
+netrecalc(void)
+{
+	Host *h;
+	Edge *e;
+	Snet *t;
+	int i;
+
+	if(myhost == nil)
+		return;
+
+	qsort(edges, nedges, sizeof(edges[0]), edgepcmp);
+	while(nedges > 0 && edges[nedges-1]->deleted){
+		reportedge(bcast, edges[--nedges]);
+		free(edges[nedges]);
+		edges[nedges] = nil;
+	}
+	for(h = hosts; h != nil; h = h->next) h->from = nil;
+
+	myhost->from = myhost;
+	myhost->connected = 1;
+
+Loop:
+	for(i=0; i<nedges; i++){
+		e = edges[i];
+		if(e->src->from == nil || (h = e->dst)->from != nil)
+			continue;
+		memmove(h->ip, e->ip, IPaddrlen);
+		h->port = e->port;
+		h->options = e->options;
+		h->from = e->src;
+		if(h->connected == 0){
+			h->connected = 1;
+			for(t = h->snet; t != nil; t = t->next)
+				t->reported = 0;
+			e->reported = 0;
+		}
+		goto Loop;
+	}
+
+	for(h = hosts; h != nil; h = h->next){
+		if(h->from == nil && h->connected){
+			h->connected = 0;
+			clearkey(h);
+			while(h->link != nil) {
+				deledge(h->link->rev);
+				deledge(h->link);
+			}
+			while(h->snet != nil) delsubnet(h->snet);
+		}
+	}
+
+	qsort(snet, nsnet, sizeof(snet[0]), subnetpcmp);
+	for(i = nsnet-1; i >= 0; i--){
+		reportsubnet(bcast, snet[i]);
+		if(snet[i]->deleted){
+			assert(i == nsnet-1);
+			nsnet = i;
+			free(snet[i]);
+			snet[i] = nil;
+		}
+	}
+
+	qsort(edges, nedges, sizeof(edges[0]), edgepcmp);
+	for(i = nedges-1; i >= 0; i--){
+		reportedge(bcast, edges[i]);
+		if(edges[i]->deleted){
+			assert(i == nedges-1);
+			nedges = i;
+			free(edges[i]);
+			edges[i] = nil;
+		}
+	}
+}
+
+Snet*
+getsubnet(Host *h, char *s, int new)
+{
+	uchar ip[IPaddrlen], mask[IPaddrlen];
+	Snet *t;
+	char *p, *e;
+	int i, prefixlen, weight;
+
+	if(parseip(ip, s) == -1)
+		return nil;
+
+	weight = 10;
+	prefixlen = 128;
+	if((p = strchr(s, '/')) != nil){
+		if((e = strchr(p+1, '#')) != nil)
+			*e = 0;
+		prefixlen = atoi(p+1) + (isv4(ip)!=0)*(128-32);
+		if(e != nil){
+			*e = '#';
+			weight = atoi(e+1);
+		}
+	}
+	memset(mask, 0, IPaddrlen);
+	for(i=0; i<prefixlen; i++)
+		mask[i/8] |= 0x80>>(i%8);
+	maskip(ip, mask, ip);
+
+	for(t = h->snet; t != nil; t = t->next)
+		if(memcmp(t->ip, ip, IPaddrlen) == 0
+		&& memcmp(t->mask, mask, IPaddrlen) == 0){
+			if(new)
+				t->weight = weight;
+			return t;
+		}
+
+	if(!new)
+		return nil;
+
+	t = emalloc(sizeof(Snet));
+	memmove(t->ip, ip, IPaddrlen);
+	memmove(t->mask, mask, IPaddrlen);
+	t->prefixlen = prefixlen - (isv4(ip)!=0)*(128-32);
+	t->weight = weight;
+	t->owner = h;
+	t->next = h->snet;
+	h->snet = t;
+	if((nsnet % 16) == 0)
+		snet = erealloc(snet, sizeof(snet[0])*(nsnet+16));
+	snet[nsnet++] = t;
+	return t;
+}
+
+void
+delsubnet(Snet *t)
+{
+	Snet **tp;
+
+	if(t == nil || t->deleted)
+		return;
+	for(tp = &t->owner->snet; *tp != nil; tp = &(*tp)->next){
+		if(*tp == t){
+			*tp = t->next;
+			break;
+		}
+	}
+	t->next = nil;
+	t->deleted = 1;
+}
+
+Edge*
+getedge(Host *src, Host *dst, int new)
+{
+	Edge *e;
+
+	for(e = src->link; e != nil; e = e->next)
+		if(e->dst == dst)
+			return e;
+	if(!new)
+		return nil;
+	e = emalloc(sizeof(Edge));
+	e->weight = MaxWeight;
+	e->src = src;
+	e->dst = dst;
+	e->next = src->link;
+	src->link = e;
+	if((e->rev = getedge(dst, src, 0)) != nil)
+		e->rev->rev = e;
+	if((nedges % 16) == 0)
+		edges = erealloc(edges, sizeof(edges[0])*(nedges+16));
+	edges[nedges++] = e;
+	return e;
+}
+
+void
+deledge(Edge *e)
+{
+	Edge **ep;
+
+	if(e == nil || e->deleted)
+		return;
+	if(e->rev != nil){
+		if(e->rev->rev != nil){
+			assert(e->rev->rev == e);
+			e->rev->rev = nil;
+		}
+		e->rev = nil;
+	}
+	for(ep = &e->src->link; *ep != nil; ep = &((*ep)->next))
+		if(*ep == e){
+			*ep = e->next;
+			break;
+		}
+	e->next = nil;
+	e->options = 0;
+	e->weight = MaxWeight;
+	e->port = 0;
+	memset(e->ip, 0, IPaddrlen);
+	e->deleted = 1;
+}
+
+Host*
+gethost(char *name, int new)
+{
+	char buf[8*1024], *s, *e, *x;
+	Host *h;
+	int fd, n;
+
+	if(*name == 0 || *name == '.' || strchr(name, '/') != nil)
+		return nil;
+	qlock(&hostslk);
+	for(h = hosts; h != nil; h = h->next)
+		if(strcmp(h->name, name) == 0)
+			goto out;
+	snprint(buf, sizeof(buf), "%s/hosts/%s", confdir, name);
+	if((fd = open(buf, OREAD)) < 0){
+		if(!new)
+			goto out;
+		buf[0] = 0;
+	} else {
+		n = read(fd, buf, sizeof(buf)-1);
+		close(fd);
+		if(n <= 0)
+			goto out;
+		buf[n] = 0;
+	}
+	h = emalloc(sizeof(Host));
+	h->name = estrdup(name);
+	h->addr = estrdup(name);
+	h->port = 655;
+	h->pmtu = DefPMTU;
+	h->options = OptClampMss;
+	h->udpfd = -1;
+	h->connected = 0;
+	h->next = hosts;
+	hosts = h;
+	if((s = (char*)decodePEM(buf, "RSA PUBLIC KEY", &n, nil)) == nil)
+		goto out;
+	h->rsapub = asn1toRSApub((uchar*)s, n);
+	free(s);
+	if(h->rsapub == nil)
+		goto out;
+	for(s = buf; s != nil; s = e){
+		char *f[2];
+
+		if((e = strchr(s, '\n')) != nil)
+			*e++ = 0;
+		if((x = strchr(s, '=')) == nil)
+			continue;
+		*x = ' ';
+		if((n = tokenize(s, f, nelem(f))) != 2)
+			continue;
+		if(cistrcmp(f[0], "Address") == 0){
+			free(h->addr);
+			h->addr = estrdup(f[1]);
+			continue;
+		}
+		if(cistrcmp(f[0], "IndirectData") == 0){
+			h->options |= OptIndirect*(cistrcmp(f[1], "yes") == 0);
+			continue;
+		}
+		if(cistrcmp(f[0], "TCPonly") == 0){
+			h->options |= OptTcpOnly*(cistrcmp(f[1], "yes") == 0);
+			continue;
+		}
+		if(cistrcmp(f[0], "ClampMSS") == 0){
+			h->options &= ~(OptClampMss*(cistrcmp(f[1], "no") == 0));
+			continue;
+		}
+		if(cistrcmp(f[0], "PMTU") == 0){
+			h->pmtu = atoi(f[1]);
+			if(h->pmtu > MaxPacket)
+				h->pmtu = MaxPacket;
+			else if(h->pmtu < 512)
+				h->pmtu = 512;
+			continue;
+		}
+		if(cistrcmp(f[0], "Port") == 0){
+			h->port = atoi(f[1]);
+			continue;
+		}
+		if(cistrcmp(f[0], "Subnet") == 0){
+			if(myhost == nil)
+				getsubnet(h, f[1], 1);
+			continue;
+		}
+	}
+	if(myhost == nil && h->snet == nil){
+		snprint(buf, sizeof(buf), "%I/%d", localip, isv4(localip) ? 32 : 128);
+		getsubnet(h, buf, 1);
+	}
+	parseip(h->ip, h->addr);
+out:
+	qunlock(&hostslk);
+	return h;
+}
+
+Host*
+findhost(uchar ip[IPaddrlen], int port)
+{
+	Host *h;
+
+	qlock(&hostslk);
+	for(h = hosts; h != nil; h = h->next){
+		if(memcmp(ip, h->ip, IPaddrlen) == 0
+		&& (port == -1 || port == h->port))
+			break;
+	}
+	qunlock(&hostslk);
+	return h;
+}
+
+AuthRpc*
+getrsarpc(void)
+{
+	AuthRpc *rpc;
+	int afd, r;
+	char *s;
+	mpint *m;
+
+	if(myhost->rsapub == nil){
+		werrstr("no RSA public key");
+		return nil;
+	}
+	if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)
+		return nil;
+	if((rpc = auth_allocrpc(afd)) == nil){
+		close(afd);
+		return nil;
+	}
+	m = mpnew(0);
+	s = smprint("proto=rsa service=tinc role=client host=%q", myhost->name);
+	r = auth_rpc(rpc, "start", s, strlen(s));
+	free(s);
+	if(r != ARok){
+		goto Err;
+	}
+	werrstr("no key found");
+	while(auth_rpc(rpc, "read", nil, 0) == ARok){
+		s = rpc->arg;
+		if(strtomp(s, &s, 16, m) == nil)
+			continue;
+		if(mpcmp(m, myhost->rsapub->n) != 0)
+			continue;
+		mpfree(m);
+		return rpc;
+	}
+Err:
+	mpfree(m);
+	auth_freerpc(rpc);
+	close(afd);
+	return nil;
+}
+void
+putrsarpc(AuthRpc *rpc)
+{
+	if(rpc == nil)
+		return;
+	close(rpc->afd);
+	auth_freerpc(rpc);
+}
+
+
+int
+conread(Conn *c)
+{
+	int n;
+
+	if(c->rp > c->buf){
+		memmove(c->buf, c->rp, c->wp - c->rp);
+		c->wp -= (c->rp - c->buf);
+		c->rp = c->buf;
+	}
+	if((n = read(c->fd, c->wp, &c->buf[sizeof(c->buf)] - c->wp)) <= 0)
+		return n;
+	if(c->cin->crypt != nil)
+		(*c->cin->crypt)((uchar*)c->wp, n, c->cin->cs);
+	c->wp += n;
+	return n;
+}
+int
+conwrite(Conn *c, char *s, int n)
+{
+	if(c->cout->crypt != nil)
+		(*c->cout->crypt)((uchar*)s, n, c->cout->cs);
+	if(write(c->fd, s, n) != n)
+		return -1;
+	return 0;
+}
+
+int
+conrecv(Conn *c, char **f, int nf)
+{
+	char *s, *e;
+
+	do {
+		if(c->wp > c->rp && (e = memchr(s = c->rp, '\n', c->wp - c->rp)) != nil){
+			*e++ = 0;
+			c->rp = e;
+if(debug) fprint(2, "<-%s %s\n", c->host != nil ? c->host->name : "???", s);
+			return tokenize(s, f, nf);
+		}
+	} while(conread(c) > 0);
+	return 0;
+}
+int
+consend(Conn *c, char *fmt, ...)
+{
+	char buf[1024];
+	va_list a;
+	int n;
+
+	if(c == nil)
+		return -1;
+
+	va_start(a, fmt);
+	n = vsnprint(buf, sizeof(buf)-2, fmt, a);
+	va_end(a);
+
+	buf[n++] = '\n';
+	buf[n] = 0;
+
+	qlock(&c->sendlk);
+if(debug) fprint(2, "->%s %s", c->host != nil ? c->host->name : "???", buf);
+	n = conwrite(c, buf, n);
+	qunlock(&c->sendlk);
+
+	return n;
+}
+
+int
+recvudp(Host *h)
+{
+	uchar buf[4+MaxPacket+AESbsize+MAClen], mac[SHA2_256dlen];
+	AESstate cs[1];
+	uint seq;
+	int n, o;
+
+	if((n = read(h->udpfd, buf, sizeof(buf))) <= 0)
+		return -1;
+	lock(h->cin);
+	if(h->cin->crypt == nil || (n -= MAClen) < AESbsize){
+		unlock(h->cin);
+		return -1;
+	}
+	hmac_sha2_256(buf, n, h->cin->key, sizeof(h->cin->key), mac, nil);
+	if(tsmemcmp(mac, buf+n, MAClen) != 0){
+		unlock(h->cin);
+		return -1;
+	}
+	memmove(cs, h->cin->cs, sizeof(cs));
+	(*h->cin->crypt)(buf, n, cs);
+
+	seq  = buf[0]<<24;
+	seq |= buf[1]<<16;
+	seq |= buf[2]<<8;
+	seq |= buf[3]<<0;
+
+	if((o = (int)(seq - h->cin->seq)) > 0){
+		h->cin->seq = seq;
+		h->ooo = o < 64 ? h->ooo<<o | 1ULL : 0ULL;
+	} else {
+		o = -o;
+		if(o >= 64 || (h->ooo & 1ULL<<o) != 0){
+			unlock(h->cin);
+			return 0;
+		}
+		h->ooo |= 1ULL<<o;
+	}
+	unlock(h->cin);
+	if((n -= buf[n-1]) < 4+EtherHdr)
+		return -1;
+	routepkt(h, buf+4, n-4);
+	return 0;
+}
+int
+sendudp(Host *h, uchar *p, int n)
+{
+	uchar buf[4+MaxPacket+AESbsize+SHA2_256dlen];
+	AESstate cs[1];
+	uint seq;
+	int pad;
+
+	if(h->udpfd < 0 || n > MaxPacket || n > h->pmtu)
+		return -1;
+	lock(h->cout);
+	if(h->cout->crypt == nil){
+		unlock(h->cout);
+		needkey(h);
+		return -1;
+	}
+
+	seq = ++h->cout->seq;
+	buf[0] = seq>>24;
+	buf[1] = seq>>16;
+	buf[2] = seq>>8;
+	buf[3] = seq>>0;
+
+	memmove(buf+4, p, n), n += 4;
+	pad = AESbsize - ((uint)n % AESbsize);
+	memset(buf+n, pad, pad), n += pad;
+	memmove(cs, h->cout->cs, sizeof(cs));
+	(*h->cout->crypt)(buf, n, cs);
+	hmac_sha2_256(buf, n, h->cout->key, sizeof(h->cout->key), buf+n, nil);
+	unlock(h->cout);
+	n += MAClen;
+	if(write(h->udpfd, buf, n) != n)
+		return -1;
+	if((seq & 0xFFFFF) == 0) needkey(h);
+	return 0;
+}
+
+int
+sendtcp(Host *h, uchar *p, int n)
+{
+	char buf[24];
+	Conn *c;
+	int m;
+
+	if((c = h->conn) == nil)
+		return -1;
+	m = snprint(buf, sizeof(buf), "17 %d\n", n);
+	qlock(&c->sendlk);
+	if(conwrite(c, buf, m) < 0
+	|| conwrite(c, (char*)p, n) < 0)
+		n = -1;
+	else
+		n = 0;
+	qunlock(&c->sendlk);
+	return n;
+}
+
+void
+forward(Host *s, Host *d, uchar *p, int n)
+{
+	if(d->from == nil)
+		return;
+	while(d != s && d != myhost){
+		if(sendudp(d, p, n) == 0)
+			return;
+		if(sendtcp(d, p, n) == 0)
+			return;
+		d = d->from;
+	}
+}
+
+int
+updatebyte(int csum, uchar *b, uchar *p, int v)
+{
+	int o;
+
+	o = *p;
+	v &= 255;
+	*p = v;
+	if(((p - b) & 1) == 0){
+		o <<= 8;
+		v <<= 8;
+	}
+	csum += o^0xFFFF;
+	csum += v;
+	while(v = csum >> 16)
+		csum = (csum & 0xFFFF) + v;
+	return csum;
+}
+
+void
+clampmss(Host *d, uchar *p, int n, int o)
+{
+	int oldmss, newmss, csum;
+	uchar *h, *e;
+
+	if(n <= TcpHdr || (p[13]&2) == 0 || (d->options & OptClampMss) == 0)
+		return;
+	if((e = p+(p[12]>>4)*4) > p+n)
+		return;
+	for(h = p+TcpHdr; h+4 <= e && h[1] > 0; h += h[1])
+		if(h[0] == 2 && h[1] == 4)
+			goto Found;
+	return;
+Found:
+	oldmss = h[2]<<8 | h[3];
+	newmss = myhost->pmtu;
+	if(d->pmtu < newmss)
+		newmss = d->pmtu;
+	newmss -= o + TcpHdr;
+	if(oldmss <= newmss)
+		return;
+if(debug) fprint(2, "clamping tcp mss %d -> %d for %s\n", oldmss, newmss, d->name);
+	csum = (p[16]<<8 | p[17]) ^ 0xFFFF;
+	csum = updatebyte(csum, p, h+2, newmss>>8);
+	csum = updatebyte(csum, p, h+3, newmss);
+	csum ^= 0xFFFF;
+	p[16] = csum>>8;
+	p[17] = csum;
+}
+
+void
+routepkt(Host *s, uchar *p, int n)
+{
+	uchar src[IPaddrlen], dst[IPaddrlen];
+	int o, type;
+	Snet *t;
+
+Ether:
+	if(n <= EtherHdr)
+		return;
+	switch(p[EtherType+0]<<8 | p[EtherType+1]){
+	default:
+		return;
+	case 0x8100:	/* VLAN */
+		memmove(p+4, p, 2*Eaddrlen);
+		p += 4, n -= 4;
+		goto Ether;
+	case 0x0800:	/* IP */
+		break;
+	}
+	switch(p[EtherHdr] & 0xF0){
+	default:
+		return;
+	case 0x40:
+		o = EtherHdr+(p[EtherHdr] & 15)*4;
+		if(n < EtherHdr+Ip4Hdr || n < o)
+			return;
+		type = p[EtherHdr+9];
+		v4tov6(src, p+EtherHdr+12);
+		v4tov6(dst, p+EtherHdr+16);
+		break;
+	case 0x60:
+		o = EtherHdr+Ip6Hdr;
+		if(n < o)
+			return;
+		type = p[EtherHdr+6];
+		memmove(src, p+EtherHdr+8, 16);
+		memmove(dst, p+EtherHdr+24, 16);
+		break;
+	}
+	netlock(nil);
+	if((t = lookupnet(dst)) != nil){
+		if(type == 6)	/* TCP */
+			clampmss(t->owner, p+o, n-o, o);
+		if(t->owner == myhost)
+			write(ipdfd, p+EtherHdr, n-EtherHdr);
+		else
+			forward(s, t->owner, p, n);
+	}
+	netunlock(nil);
+}
+
+void
+updateweight(Edge *e, int ms)
+{
+	e->weight = (e->weight + ms) / 2;
+	if(e->weight < 0)
+		e->weight = 0;
+}
+
+int
+metaauth(Conn *c)
+{
+	mpint *m, *h;
+	uchar b[256];
+	AuthRpc *rpc;
+	char *f[8];
+	int n, n1, n2, ms;
+	Edge *e;
+
+	c->pingtime = nsec();
+	if(consend(c, "%d %s 17", ID, myhost->name) < 0)
+		return -1;
+	n = conrecv(c, f, nelem(f));
+	if(n != 3 || atoi(f[0]) != ID || atoi(f[2]) != 17)
+		return -1;
+	if((c->host = gethost(f[1], 0)) == nil
+	|| c->host == myhost || c->host->rsapub == nil)
+		return -1;
+
+	n1 = (mpsignif(c->host->rsapub->n)+7)/8;
+	if(n1 < AESkeylen+AESbsize || n1 > sizeof(b))
+		return -1;
+	n2 = (mpsignif(myhost->rsapub->n)+7)/8;
+	if(n2 < AESkeylen+AESbsize || n2 > sizeof(b))
+		return -1;
+
+	m = mpnrand(c->host->rsapub->n, genrandom, nil);
+	mptober(m, b, n1);
+	setupAESstate(c->cout->cs, b+n1-AESkeylen, AESkeylen, b+n1-AESkeylen-AESbsize);
+	rsaencrypt(c->host->rsapub, m, m);
+	mptober(m, b, n1);
+	mpfree(m);
+	if(consend(c, "%d %d %d 0 0 %.*H", META_KEY, EVP_AES256CFB, EVP_SHA256, n1, b) < 0)
+		return -1;
+	c->cout->crypt = aesCFBencrypt;
+
+	n = conrecv(c, f, nelem(f));
+	if(n != 6 || atoi(f[0]) != META_KEY || strlen(f[5]) != 2*n2)
+		return -1;
+	if(atoi(f[1]) != EVP_AES256CFB || atoi(f[2]) != EVP_SHA256){
+		fprint(2, "%s uses unknown cipher/digest agorithms: %s %s\n",
+			c->host->name, f[1], f[2]);
+		return -1;
+	}
+
+	if((rpc = getrsarpc()) == nil
+	|| auth_rpc(rpc, "write", f[5], strlen(f[5])) != ARok
+	|| auth_rpc(rpc, "read", nil, 0) != ARok){
+		putrsarpc(rpc);
+		return -1;
+	}
+
+	m = strtomp(rpc->arg, nil, 16, nil);
+	putrsarpc(rpc);
+	mptober(m, b, n2);
+	mpfree(m);
+	setupAESstate(c->cin->cs, b+n2-AESkeylen, AESkeylen, b+n2-AESkeylen-AESbsize);
+	c->cin->crypt = aesCFBdecrypt;
+
+	h = mpnrand(c->host->rsapub->n, genrandom, nil);
+	mptober(h, b, n1);
+	if(consend(c, "%d %.*H", CHALLENGE, n1, b) < 0){
+		mpfree(h);
+		return -1;
+	}
+	sha2_256(b, n1, b, nil);
+	betomp(b, SHA2_256dlen, h);
+
+	n = conrecv(c, f, nelem(f));
+	if(n != 2 || atoi(f[0]) != CHALLENGE){
+		mpfree(h);
+		return -1;
+	}
+	m = strtomp(f[1], nil, 16, nil);
+	mptober(m, b, n2);
+	mpfree(m);
+	sha2_256(b, n2, b, nil);
+	if(consend(c, "%d %.*H", CHAL_REPLY, SHA2_256dlen, b) < 0){
+		mpfree(h);
+		return -1;
+	}
+	n = conrecv(c, f, nelem(f));
+	if(n != 2 || atoi(f[0]) != CHAL_REPLY){
+		mpfree(h);
+		return -1;
+	}
+	m = strtomp(f[1], nil, 16, nil);
+	n = mpcmp(m, h);
+	mpfree(m);
+	mpfree(h);
+	if(n != 0)
+		return -1;
+	ms = (nsec() - c->pingtime)/1000000LL;
+	if(consend(c, "%d %d %d %x", ACK, myhost->port, ms, myhost->options) < 0)
+		return -1;
+	n = conrecv(c, f, nelem(f));
+	if(n != 4 || atoi(f[0]) != ACK)
+		return -1;
+
+	netlock(c);
+	e = getedge(myhost, c->host, 1);
+	memmove(e->ip, c->ip, IPaddrlen);
+	e->port = atoi(f[1]);
+	e->weight = atoi(f[2]);
+	e->options = strtol(f[3], nil, 16);
+	updateweight(e, ms);
+	c->pingtime = 0;
+	c->edge = e;
+	c->host->conn = c;
+	netunlock(c);
+
+	return 0;
+}
+
+Conn*
+nearcon(Host *to)
+{
+	while(to != nil && to != myhost){
+		if(to->conn != nil)
+			return to->conn;
+		to = to->from;
+	}
+	return nil;
+}
+
+void
+sendkey(Host *to)
+{
+	lock(to->cin);
+	to->ooo = 0;
+	to->cin->seq = 0;
+	genrandom(to->cin->key, sizeof(to->cin->key));
+	setupAESstate(to->cin->cs, to->cin->key, AESkeylen, to->cin->key+AESkeylen);
+	to->cin->crypt = aesCBCdecrypt;
+	unlock(to->cin);
+
+	consend(nearcon(to), "%d %s %s %.*H %d %d %d %d", ANS_KEY,
+		myhost->name, to->name,
+		sizeof(to->cin->key), to->cin->key,
+		EVP_AES256CBC, EVP_SHA256, MAClen, 0);
+}
+void
+needkey(Host *from)
+{
+	consend(nearcon(from), "%d %s %s", REQ_KEY, myhost->name, from->name);
+}
+void
+recvkey(Host *from, char **f)
+{
+	uchar key[sizeof(from->cout->key)];
+	mpint *m;
+
+	if(atoi(f[1]) != EVP_AES256CBC || atoi(f[2]) != EVP_SHA256
+	|| atoi(f[3]) != MAClen || atoi(f[4]) != 0){
+		fprint(2, "%s key uses unknown parameters: %s %s %s %s\n",
+			from->name, f[1], f[2], f[3], f[4]);
+		return;
+	}
+	if(strlen(f[0]) != sizeof(key)*2)
+		return;
+	if((m = strtomp(f[0], nil, 16, nil)) == nil)
+		return;
+	mptober(m, key, sizeof(key));
+	mpfree(m);
+	lock(from->cout);
+	if(tsmemcmp(key, from->cout->key, sizeof(key)) == 0)
+		goto Out;
+	from->cout->seq = 0;
+	memmove(from->cout->key, key, sizeof(key));
+	setupAESstate(from->cout->cs, from->cout->key, AESkeylen, from->cout->key+AESkeylen);
+	from->cout->crypt = aesCBCencrypt;
+Out:
+	unlock(from->cout);
+	memset(key, 0, sizeof(key));
+}
+void
+clearkey(Host *from)
+{
+	lock(from->cout);
+	from->cout->crypt = nil;
+	from->cout->seq = 0;
+	memset(from->cout->cs, 0, sizeof(from->cout->cs));
+	genrandom(from->cout->key, sizeof(from->cout->key));
+	unlock(from->cout);
+}
+
+void
+metapeer(Conn *c)
+{
+	char *f[8];
+	Host *h, *r;
+	Edge *e;
+	Snet *t;
+	int i, n;
+
+	netlock(nil);
+	for(i=0; i<nsnet; i++)
+		reportsubnet(c, snet[i]);
+	for(i=0; i<nedges; i++)
+		reportedge(c, edges[i]);
+	netunlock(nil);
+
+	sendkey(c->host);
+	while((n = conrecv(c, f, nelem(f))) > 0){
+		switch(atoi(f[0])){
+		case PING:
+			if(consend(c, "%d %x", PONG, rand()) < 0)
+				return;
+			continue;
+		case PONG:
+			netlock(c);
+			if(c->pingtime != 0){
+				if((e = getedge(myhost, c->host, 0)) != nil)
+					updateweight(e, (nsec() - c->pingtime) / 1000000LL);
+				c->pingtime = 0;
+			}
+			netunlock(c);
+			continue;
+		case ADD_SUBNET:
+			if(n != 4 || (h = gethost(f[2], 1)) == nil || h == myhost)
+				break;
+			netlock(c);
+			getsubnet(h, f[3], 1);
+			netunlock(c);
+			continue;
+		case DEL_SUBNET:
+			if(n != 4 || (h = gethost(f[2], 0)) == nil || h == myhost)
+				break;
+			netlock(c);
+			if((t = getsubnet(h, f[3], 0)) != nil)
+				delsubnet(t);
+			netunlock(c);
+			continue;
+		case ADD_EDGE:
+			if(n != 8 || (h = gethost(f[2], 1)) == nil || h == myhost
+			|| (r = gethost(f[3], 1)) == nil)
+				break;
+			netlock(c);
+			if((e = getedge(h, r, 1)) != nil){
+				if(parseip(e->ip, f[4]) == -1)
+					memmove(e->ip, r->ip, IPaddrlen);
+				e->port = atoi(f[5]);
+				e->weight = atoi(f[7]);
+				e->options = strtol(f[6], nil, 16);
+			}
+			netunlock(c);
+			continue;
+		case DEL_EDGE:
+			if(n != 4 || (h = gethost(f[2], 0)) == nil || h == myhost
+			|| (r = gethost(f[3], 1)) == nil)
+				break;
+			netlock(c);
+			if((e = getedge(h, r, 0)) != nil)
+				deledge(e);
+			netunlock(c);
+			continue;
+		case KEY_CHANGED:
+			if(n != 3 || (h = gethost(f[2], 0)) == nil || h == myhost)
+				break;
+			netlock(c);
+			clearkey(h);
+			for(e = myhost->link; e != nil; e = e->next)
+				if(e->dst->conn != c && e->dst->from == myhost)
+					consend(e->dst->conn, "%s %s %s", f[0], f[1], f[2]);
+			netunlock(c);
+			continue;
+		case REQ_KEY:
+			if(n != 3 || (h = gethost(f[1], 0)) == nil || h == myhost
+			|| (r = gethost(f[2], 0)) == nil)
+				break;
+			netlock(nil);
+			if(r != myhost)
+				consend(nearcon(r), "%s %s %s", f[0], f[1], f[2]);
+			else
+				sendkey(h);
+			netunlock(nil);
+			continue;
+		case ANS_KEY:
+			if(n != 8 || (h = gethost(f[1], 0)) == nil || h == myhost
+			|| (r = gethost(f[2], 0)) == nil)
+				break;
+			netlock(nil);
+			if(r != myhost)
+				consend(nearcon(r), "%s %s %s %s %s %s %s %s",
+					f[0], f[1], f[2], f[3],
+					f[4], f[5], f[6], f[7]);
+			else
+				recvkey(h, &f[3]);
+			netunlock(nil);
+			continue;
+		case TCP_PACKET:
+			if(n != 2)
+				return;
+			n = atoi(f[1]);
+			if(n < 0 || n > MaxPacket)
+				return;
+			while((c->wp - c->rp) < n && conread(c) > 0)
+				;
+			if(c->wp - c->rp < n)
+				return;
+			routepkt(c->host, (uchar*)c->rp, n);
+			c->rp += n;
+			continue;
+		}
+	}
+}
+
+void
+tcpclient(int fd)
+{
+	Conn *c;
+	char dir[128];
+
+	c = emalloc(sizeof(Conn));
+	c->host = nil;
+	c->fd = fd;
+	c->rp = c->wp = c->buf;
+	c->port = dir2ipport(fd2dir(fd, dir, sizeof(dir)), c->ip);
+	procsetname("tcpclient %s %s %I!%d", myhost->name,
+		dir, c->ip, c->port);
+	if(metaauth(c) == 0){
+		procsetname("tcpclient %s %s %I!%d %s", myhost->name,
+			dir, c->ip, c->port, c->host->name);
+		metapeer(c);
+	}
+	netlock(c);
+	if(c->host != nil && c->host->conn == c){
+		c->host->conn = nil;
+		if(c->edge != nil && c->edge->dst == c->host){
+			deledge(c->edge->rev);
+			deledge(c->edge);
+		}
+		hangupfd(c->host->udpfd);
+	}
+	netunlock(c);
+	memset(c, 0, sizeof(*c));
+	free(c);
+	close(fd);
+}
+
+void
+udpclient(int fd)
+{
+	uchar ip[IPaddrlen];
+	char dir[128];
+	Host *h;
+
+	if((h = findhost(ip, dir2ipport(fd2dir(fd, dir, sizeof(dir)), ip))) != nil
+	&& h != myhost){
+		procsetname("udpclient %s %s %I!%d %s", myhost->name,
+			dir, h->ip, h->port, h->name);
+		h->udpfd = fd;
+		do {
+			alarm(15*1000);
+		} while(recvudp(h) == 0);
+		if(h->udpfd == fd)
+			h->udpfd = -1;
+	}
+	close(fd);
+}
+
+int
+dialer(char *proto, char *host, int rport, int lport)
+{
+	char addr[40], local[16];
+	int dfd;
+
+	snprint(local, sizeof(local), "%d", lport);
+	snprint(addr, sizeof(addr), "%s/%s!%s!%d", outside, proto, host, rport);
+	procsetname("dialer %s %s", myhost->name, addr);
+
+	for(;;){
+		if((dfd = dial(addr, lport ? local : nil, nil, nil)) >= 0){
+			switch(rfork(RFPROC|RFMEM)){
+			case 0:
+				return dfd;
+			case -1:
+				close(dfd);
+				continue;
+			}
+			if(waitpid() < 0)
+				return -1;
+		}
+		sleep(10000);
+	}
+}
+
+int
+listener(char *proto, int port, int nprocs)
+{
+	char addr[40], adir[40], ldir[40];
+	int acfd, lcfd, dfd;
+
+	snprint(addr, sizeof(addr), "%s/%s!*!%d", outside, proto, port);
+	procsetname("listener %s %s", myhost->name, addr);
+
+	if((acfd = announce(addr, adir)) < 0)
+		return -1;
+	while((lcfd = listen(adir, ldir)) >= 0){
+		if((dfd = accept(lcfd, ldir)) >= 0)
+			switch(rfork(RFPROC|RFMEM)){
+			default:
+				if(nprocs > 1 || waitpid() < 0) nprocs--;
+				break;
+			case 0:
+				return dfd;
+			case -1:
+				close(dfd);
+			}
+		close(lcfd);
+	}
+	close(acfd);
+	return -1;
+}
+
+void
+pingpong(void)
+{
+	Edge *e;
+	Conn *c;
+
+	procsetname("pingpong %s", myhost->name);
+	for(;;){
+		sleep(15*1000 + (rand() % 3000));
+		netlock(nil);
+		for(e = myhost->link; e != nil; e = e->next){
+			if((c = e->dst->conn) != nil){
+				if(c->pingtime != 0){
+					hangupfd(c->fd);
+					continue;
+				}
+				c->pingtime = nsec();
+				consend(c, "%d %x", PING, rand());
+			}
+		}
+		netunlock(nil);
+	}
+}
+
+void
+ipifcsetup(void)
+{
+	char buf[128];
+	int n;
+
+	snprint(buf, sizeof buf, "%s/ipifc/clone", inside);
+	if((ipcfd = open(buf, ORDWR)) < 0)
+		sysfatal("can't open ip interface: %r");
+	if((n = read(ipcfd, buf, sizeof buf - 1)) <= 0)
+		sysfatal("can't read interface number: %r");
+	buf[n] = 0;
+	ipifn = atoi(buf);
+	snprint(buf, sizeof buf, "%s/ipifc/%d/data", inside, ipifn);
+	if((ipdfd = open(buf, ORDWR)) < 0)
+		sysfatal("can't open ip data: %r");
+	fprint(ipcfd, "bind pkt");
+	fprint(ipcfd, "mtu %d", myhost->pmtu-EtherHdr);
+	fprint(ipcfd, "add %I %M", localip, localmask);
+}
+
+void
+ip2tunnel(void)
+{
+	uchar buf[MaxPacket];
+	int n;
+
+	procsetname("ip2tunnel %s %s %I %M", myhost->name,
+		fd2dir(ipdfd, (char*)buf, sizeof(buf)),
+		localip, localmask);
+	while((n = read(ipdfd, buf+EtherHdr, sizeof buf-EtherHdr)) > 0){
+		memset(buf, 0, 2*Eaddrlen);
+		buf[EtherType+0] = 0x08;
+		buf[EtherType+1] = 0x00;
+		routepkt(myhost, buf, n+EtherHdr);
+	}
+}
+
+void
+catch(void*, char *msg)
+{
+	if(strcmp(msg, "alarm") == 0 || strcmp(msg, "interrupt") == 0)
+		noted(NCONT);
+	noted(NDFLT);
+}
+void
+shutdown(void)
+{
+	postnote(PNGROUP, getpid(), "shutdown");
+}
+
+void
+usage(void)
+{
+	fprint(2, "%s [-d] [-p maxprocs] [-x inside] [-o outside] [-c confdir] [-n myname] "
+		"localip localmask [host...]\n", argv0);
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	Host *h;
+	Snet *t;
+	AuthRpc *rpc;
+	int i;
+
+	quotefmtinstall();
+	fmtinstall('I', eipfmt);
+	fmtinstall('M', eipfmt);
+	fmtinstall('H', encodefmt);
+
+	ARGBEGIN {
+	case 'd':
+		debug++;
+		break;
+	case 'p':
+		if((maxprocs = atoi(EARGF(usage()))) < 1)
+			sysfatal("bad number of procs");
+		break;
+	case 'c':
+		confdir = EARGF(usage());
+		break;
+	case 'n':
+		myname = EARGF(usage());
+		break;
+	case 'x':
+		outside = inside = EARGF(usage());
+		break;
+	case 'o':
+		outside = EARGF(usage());
+		break;
+	default:
+		usage();
+	} ARGEND;
+
+	if(argc < 2)
+		usage();
+	if(parseip(localip, argv[0]) == -1)
+		sysfatal("bad local ip: %s", argv[0]);
+	if(parseipmask(localmask, argv[1]) == -1)
+		sysfatal("bad local mask: %s", argv[1]);
+	argv += 2, argc -= 2;
+
+	srand(fastrand());
+	if(myname == nil)
+		myname = sysname();
+	if((myhost = gethost(myname, 0)) == nil)
+		sysfatal("can't get my host: %r");
+	if((rpc = getrsarpc()) == nil)
+		sysfatal("can't find my key in factotum: %r");
+	putrsarpc(rpc);
+
+	for(i = 0; i < argc; i++){
+		if((h = gethost(argv[i], 0)) == nil)
+			sysfatal("unknown host: %s", *argv);
+		if(h == myhost)
+			sysfatal("will not connect to myself");
+		if(h->rsapub == nil)
+			sysfatal("no RSA public key for: %s", h->name);
+	}
+
+	if((t = lookupnet(localip)) == nil)
+		sysfatal("no subnet found for local ip %I", localip);
+	if(t->owner != myhost)
+		sysfatal("local ip %I belongs to host %s subnet %I/%d",
+			localip, t->owner->name, t->ip, t->prefixlen);
+
+	ipifcsetup();
+	notify(catch);
+	switch(rfork(RFPROC|RFFDG|RFREND|RFNOTEG)){
+	case -1:
+		sysfatal("can't fork: %r");
+	case 0:
+		break;
+	default:
+		if(debug){
+			waitpid();
+			fprint(ipcfd, "unbind");
+		}
+		exits(nil);
+	}
+	atexit(shutdown);
+	if(rfork(RFPROC|RFMEM) == 0){
+		tcpclient(listener("tcp", myhost->port, maxprocs));
+		exits(nil);
+	}
+	if(rfork(RFPROC|RFMEM) == 0){
+		udpclient(listener("udp", myhost->port, maxprocs));
+		exits(nil);
+	}
+	for(i = 0; i < argc; i++){
+		if((h = gethost(argv[i], 0)) == nil)
+			continue;
+		if(rfork(RFPROC|RFMEM) == 0){
+			tcpclient(dialer("tcp", h->addr, h->port, myhost->port));
+			exits(nil);
+		}
+		if(rfork(RFPROC|RFMEM) == 0){
+			udpclient(dialer("udp", h->addr, h->port, myhost->port));
+			exits(nil);
+		}
+	}
+	if(rfork(RFPROC|RFMEM) == 0){
+		pingpong();
+		exits(nil);
+	}
+	ip2tunnel();
+}