From 6dd1aea74b5e9b8294711367c327e14752c83a00 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Tue, 24 Mar 1998 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1998-03-24

---
 ip/devip.c |   5 +-
 ip/ip.h    |   3 +
 ip/ipmux.c | 728 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 pc/pci.c   |   2 +-
 4 files changed, 736 insertions(+), 2 deletions(-)
 create mode 100644 ip/ipmux.c

diff --git a/ip/devip.c b/ip/devip.c
index 3aef82aaa8b15512ac80b2d7fdeaea23e59c66c5..d92d24e93ed8e86aec668168bbe695fe1a2a8446 100644
--- a/ip/devip.c
+++ b/ip/devip.c
@@ -1080,7 +1080,10 @@ Fsconnected(Conv* c, char* msg)
 Proto*
 Fsrcvpcol(Fs* f, uchar proto)
 {
-	return f->t2p[proto];
+	if(f->t2m[proto] && f->ipmux)
+		return f->ipmux;
+	else
+		return f->t2p[proto];
 }
 
 Conv*
diff --git a/ip/ip.h b/ip/ip.h
index cc663d48388991e6f7970758225c5957db8ecd04..13033aea786f75841e648ce73099e72459b25b02 100644
--- a/ip/ip.h
+++ b/ip/ip.h
@@ -8,6 +8,7 @@ typedef struct	Ipselftab	Ipselftab;
 typedef struct	Iplink	Iplink;
 typedef struct	Iplifc	Iplifc;
 typedef struct	Ipmulti	Ipmulti;
+typedef struct	Ipmux	Ipmux;
 typedef struct	IProuter IProuter;
 typedef struct	Ipifc	Ipifc;
 typedef struct	Log	Log;
@@ -241,7 +242,9 @@ struct Fs
 	int	np;
 	Proto*	p[Maxproto+1];		/* list of supported protocols */
 	Proto*	t2p[256];		/* vector of all ip protocol handlers */
+	Ipmux*	t2m[256];		/* vector of all ip multiplexors */
 	Proto*	ipifc;			/* kludge for ipifcremroute & ipifcaddroute */
+	Proto*	ipmux;			/* kludge for finding an ip multiplexor */
 
 	IP	*ip;
 	Ipselftab	*self;
diff --git a/ip/ipmux.c b/ip/ipmux.c
new file mode 100644
index 0000000000000000000000000000000000000000..c4659fff29533862eabb667ecd34e1ba92275a9a
--- /dev/null
+++ b/ip/ipmux.c
@@ -0,0 +1,728 @@
+#include "u.h"
+#include "../port/lib.h"
+#include "mem.h"
+#include "dat.h"
+#include "fns.h"
+#include "../port/error.h"
+
+#include "ip.h"
+
+#define DPRINT if(0)print
+
+typedef struct Iphdr	Iphdr;
+
+enum
+{
+	IPHDR		= 20,		/* sizeof(Iphdr) */
+};
+
+struct Iphdr
+{
+	uchar	vihl;		/* Version and header length */
+	uchar	tos;		/* Type of service */
+	uchar	length[2];	/* packet length */
+	uchar	id[2];		/* ip->identification */
+	uchar	frag[2];	/* Fragment information */
+	uchar	ttl;		/* Time to live */
+	uchar	proto;		/* Protocol */
+	uchar	cksum[2];	/* Header checksum */
+	uchar	src[4];		/* IP source */
+	uchar	dst[4];		/* IP destination */
+};
+
+enum
+{
+	Tproto,
+	Tdata,
+	Tdst,
+	Tsrc,
+	Tifc,
+};
+
+char *ftname[] = 
+{
+[Tproto]	"proto",
+[Tdata]		"data",
+[Tdst]		"dst",
+[Tsrc]		"src",
+[Tifc]		"ifc",
+};
+
+typedef struct Ipmux Ipmux;
+
+struct Ipmux
+{
+	Ipmux	*yes;
+	Ipmux	*no;
+	uchar	type;
+	ushort	len;		/* length in bytes of item to compare */
+	ushort	off;		/* offset of comparison */
+	int	n;		/* number of items val points to */
+	uchar	*val;
+	uchar	*mask;
+
+	int	ref;		/* so we can garbage collect */
+};
+
+static char*
+skipwhite(char *p)
+{
+	while(*p == ' ' || *p == '\t')
+		p++;
+	return p;
+}
+
+static char*
+follows(char *p, char c)
+{
+	char *f;
+
+	f = strchr(p, c);
+	if(f == nil)
+		return nil;
+	*f++ = 0;
+	f = skipwhite(f);
+	if(*f == 0)
+		return nil;
+	return f;
+}
+
+static Ipmux*
+parseop(char **pp)
+{
+	char *p = *pp;
+	int type, off, end, len;
+	Ipmux *f;
+
+	off = 0;
+	p = skipwhite(p);
+	if(strncmp(p, "dst", 3) == 0){
+		type = Tdst;
+		len = IPaddrlen;
+		p += 3;
+	}
+	else if(strncmp(p, "src", 3) == 0){
+		type = Tsrc;
+		len = IPaddrlen;
+		p += 3;
+	}
+	else if(strncmp(p, "ifc", 3) == 0){
+		type = Tifc;
+		len = IPaddrlen;
+		p += 3;
+	}
+	else if(strncmp(p, "proto", 5) == 0){
+		type = Tproto;
+		len = 1;
+		p += 5;
+	}
+	else if(strncmp(p, "data", 4) == 0){
+		type = Tdata;
+		p += 4;
+		p = skipwhite(p);
+		if(*p != '[')
+			return nil;
+		p++;
+		off = strtoul(p, &p, 0);
+		p = skipwhite(p);
+		if(*p != ':')
+			end = off;
+		else {
+			p++;
+			p = skipwhite(p);
+			end = strtoul(p, &p, 0);
+			if(end < off)
+				return nil;
+			p = skipwhite(p);
+		}
+		if(*p != ']')
+			return nil;
+		len = end - off + 1;
+		p++;
+	}
+	else 
+		return nil;
+
+	f = smalloc(sizeof(*f));
+	f->type = type;
+	f->len = len;
+	f->off = off;
+	f->val = nil;
+	f->mask = nil;
+	f->n = 1;
+	f->ref = 1;
+
+	return f;	
+}
+
+static int
+htoi(char x)
+{
+	if(x >= '0' && x <= '9')
+		x -= '0';
+	else if(x >= 'a' && x <= 'f')
+		x -= 'a' - 10;
+	else if(x >= 'A' && x <= 'F')
+		x -= 'A' - 10;
+	else
+		x = 0;
+	return x;
+}
+
+static int
+hextoi(char *p)
+{
+	return (htoi(p[0])<<4) | htoi(p[1]);
+}
+
+static void
+parseval(uchar *v, char *p, int len)
+{
+	while(*p && len-- > 0){
+		*v++ = hextoi(p);
+		p += 2;
+	}
+}
+
+static Ipmux*
+parsedemux(char *p)
+{
+	int n;
+	Ipmux *f;
+	char *val;
+	char *mask;
+	char *vals[20];
+	uchar *v;
+
+	/* parse operand */
+	f = parseop(&p);
+	if(f == nil)
+		return nil;
+
+	/* find value */
+	val = follows(p, '=');
+	if(val == nil)
+		goto parseerror;
+
+	/* parse mask */
+	mask = follows(p, '&');
+	if(mask != nil){
+		switch(f->type){
+		case Tsrc:
+		case Tdst:
+		case Tifc:
+			f->mask = smalloc(f->len);
+			parseipmask(f->mask, mask);
+			break;
+		case Tdata:
+			f->mask = smalloc(f->len);
+			parseval(f->mask, mask, f->len);
+			break;
+		default:
+			goto parseerror;
+		}
+	} else
+		f->mask = nil;
+
+	/* parse vals */
+	f->n = tokenize(val, vals, sizeof(vals)/sizeof(char*));
+	if(f->n == 0)
+		goto parseerror;
+	f->val = smalloc(f->n*f->len);
+	v = f->val;
+	for(n = 0; n < f->n; n++){
+		switch(f->type){
+		case Tsrc:
+		case Tdst:
+		case Tifc:
+			parseip(v, vals[n]);
+			break;
+		case Tproto:
+		case Tdata:
+			parseval(v, vals[n], f->len);
+			break;
+		}
+		v += f->len;
+	}
+
+	return f;
+
+parseerror:
+	if(f->mask)
+		free(f->mask);
+	if(f->val)
+		free(f->val);
+	free(f);
+	return nil;
+}
+
+/*
+ *  Compare relative ordering of two ipmuxs.  This doesn't compare the
+ *  values, just the fields being looked at.  
+ *
+ *  returns:	<0 if a is a more specific match
+ *		 0 if a and b are matching on the same fields
+ *		>0 if b is a more specific match
+ */
+static int
+ipmuxcmp(Ipmux *a, Ipmux *b)
+{
+	int n;
+
+	/* compare types, lesser ones are more important */
+	n = a->type - b->type;
+	if(n != 0)
+		return n;
+
+	/* compare offsets, call earlier ones more specific */
+	n = a->off - b->off;
+	if(n != 0)
+		return n;
+
+	/* compare match lengths, longer ones are more specific */
+	n = b->len - a->len;
+	if(n != 0)
+		return n;
+
+	/*
+	 *  if we get here we have two entries matching
+	 *  the same bytes of the record.  Now check
+	 *  the mask for equality.  Longer masks are
+	 *  more specific.
+	 */
+	if(a->mask != nil && b->mask == nil)
+		return -1;
+	if(a->mask == nil && b->mask != nil)
+		return 1;
+	if(a->mask != nil && b->mask != nil){
+		n = memcmp(b->mask, a->mask, a->len);
+		if(n != 0)
+			return n;
+	}
+	return 0;
+}
+
+/*
+ *  Compare the values of two ipmuxs.  We're assuming that ipmuxcmp
+ *  returned 0 comparing them.
+ */
+static int
+ipmuxvalcmp(Ipmux *a, Ipmux *b)
+{
+	int n;
+
+	n = b->len*b->n - a->len*a->n;
+	if(n != 0)
+		return n;
+	return memcmp(a->val, b->val, a->len*a->n);
+} 
+
+/*
+ *  add onto an existing ipmux chain in the canonical comparison
+ *  order
+ */
+static void
+ipmuxchain(Ipmux **l, Ipmux *f)
+{
+	for(; *l; l = &(*l)->yes)
+		if(ipmuxcmp(f, *l) < 0)
+			break;
+	f->yes = *l;
+	*l = f;
+}
+
+/*
+ *  copy a tree
+ */
+static Ipmux*
+ipmuxcopy(Ipmux *f)
+{
+	Ipmux *nf;
+
+	if(f == nil)
+		return nil;
+	nf = smalloc(sizeof *nf);
+	*nf = *f;
+	nf->no = ipmuxcopy(f->no);
+	nf->yes = ipmuxcopy(f->yes);
+	nf->val = smalloc(f->n*f->len);
+	memmove(nf->val, f->val, f->n*f->len);
+	return nf;
+}
+
+static void
+ipmuxfree(Ipmux *f)
+{
+	if(f->val != nil)
+		free(f->val);
+	free(f);
+}
+
+static void
+ipmuxtreefree(Ipmux *f)
+{
+	if(f->no != nil)
+		ipmuxfree(f->no);
+	if(f->yes != nil)
+		ipmuxfree(f->yes);
+	ipmuxfree(f);
+}
+
+/*
+ *  merge two trees
+ */
+static Ipmux*
+ipmuxmerge(Ipmux *a, Ipmux *b)
+{
+	int n;
+	Ipmux *f;
+
+	if(a == nil)
+		return b;
+	if(b == nil)
+		return a;
+	n = ipmuxcmp(a, b);
+	if(n < 0){
+		f = ipmuxcopy(b);
+		a->yes = ipmuxmerge(a->yes, b);
+		a->no = ipmuxmerge(a->no, f);
+		return a;
+	}
+	if(n > 0){
+		f = ipmuxcopy(a);
+		b->yes = ipmuxmerge(b->yes, a);
+		b->no = ipmuxmerge(b->no, f);
+		return b;
+	}
+	if(ipmuxvalcmp(a, b) == 0){
+		a->yes = ipmuxmerge(a->yes, b->yes);
+		a->no = ipmuxmerge(a->no, b->no);
+		a->ref++;
+		ipmuxfree(b);
+		return a;
+	}
+	a->no = ipmuxmerge(a->no, b);
+	return a;
+}
+
+/*
+ *  remove a chain from a demux tree.  This is like merging accept that
+ *  we remove instead of insert.
+ */
+int
+ipmuxremove(Ipmux **l, Ipmux *f)
+{
+	int n, rv;
+	Ipmux *ft;
+
+	if(f == nil)
+		return 0;		/* we've removed it all */
+	if(*l == nil)
+		return -1;
+
+	ft = *l;
+	n = ipmuxcmp(ft, f);
+	if(n < 0){
+		/* *l is maching an earlier field, descend both paths */
+		rv = ipmuxremove(&ft->yes, f);
+		rv += ipmuxremove(&ft->no, f);
+		return rv;
+	}
+	if(n > 0){
+		/* f represents an earlier field than *l, this should be impossible */
+		return -1;
+	}
+
+	/* if we get here f and *l are comparing the same fields */
+	if(ipmuxvalcmp(ft, f) != 0){
+		/* different values mean mutually exclusive */
+		return ipmuxremove(&ft->no, f);
+	}
+
+	/* we found a match */
+	if(--(ft->ref) == 0){
+		/*
+		 *  a dead node implies the whole yes side is also dead.
+		 *  since our chain is constrained to be on that side,
+		 *  we're done.
+		 */
+		ipmuxtreefree(ft->yes);
+		*l = ft->no;
+		ipmuxfree(ft);
+		return 0;
+	}
+
+	/*
+	 *  free the rest of the chain.  it is constrained to match the
+	 *  yes side.
+	 */
+	return ipmuxremove(&ft->yes, f->yes);
+}
+
+void
+printtree(Biobuf *b, Ipmux *f, int level)
+{
+	int i, j;
+	uchar *p;
+
+	if(f == nil) {
+		Bprint(b, "\n");
+		return;
+	}
+	for(i = 0; i < level; i++)
+		Bprint(b, " ");
+	Bprint(b, "%s", ftname[f->type]);
+	if(f->type == Tdata)
+		Bprint(b, "[%d:%d]", f->off, f->off+f->len-1);
+	if(f->mask){
+		switch(f->type){
+		case Tifc:
+		case Tsrc:
+		case Tdst:
+			Bprint(b, " & %M", f->mask);
+			break;
+		case Tproto:
+		case Tdata:
+			Bprint(b, " & ");
+			for(j = 0; j < f->len; j++)
+				Bprint(b, "%2.2ux", f->mask[j]);
+			break;
+		}
+	}
+	p = f->val;
+	Bprint(b, " =");
+	for(i = 0; i < f->n; i++){
+		switch(f->type){
+		case Tifc:
+		case Tsrc:
+		case Tdst:
+			Bprint(b, " %I", p);
+			break;
+		case Tproto:
+		case Tdata:
+			Bprint(b, " ");
+			for(j = 0; j < f->len; j++)
+				Bprint(b, "%2.2ux", p[j]);
+			break;
+		}
+		p += f->len;
+	}
+	Bprint(b, "\n");
+	printtree(b, f->yes, level+1);
+	printtree(b, f->no, level+1);
+}
+
+void
+main(void)
+{
+	Ipmux *f, *f1, *f2, *f1copy, *f2copy;
+	Ipmux *root;
+	Biobuf out;
+
+	Binit(&out, 1, OWRITE);
+	fmtinstall('I', eipconv);
+	fmtinstall('M', eipconv);
+
+	Bprint(&out, "demux 1:\n");
+	f1 = parsedemux("data[0:3] = 12345678 23456789 3456789a");
+	f = parsedemux("ifc = 135.104.9.2");
+	ipmuxchain(&f1, f);
+	f = parsedemux("src & 255.255.255.0 = 135.104.9.2");
+	ipmuxchain(&f1, f);
+	f = parsedemux("proto = 17");
+	ipmuxchain(&f1, f);
+	printtree(&out, f1, 0);
+
+	f1copy = ipmuxcopy(f1);
+
+	Bprint(&out, "demux 2:\n");
+	f2 = parsedemux("data[0:3] = 12345678 23456789 3456789a");
+	f = parsedemux("ifc = 135.104.9.1");
+	ipmuxchain(&f2, f);
+	f = parsedemux("src & 255.255.255.0 = 135.104.9.3");
+	ipmuxchain(&f2, f);
+	printtree(&out, f2, 0);
+
+	f2copy = ipmuxcopy(f2);
+
+	Bprint(&out, "merged demux:\n");
+	root = ipmuxmerge(f1, f2);
+	printtree(&out, root, 0);
+	
+	Bprint(&out, "demux 1 removed:\n");
+	ipmuxremove(&root, f1copy);
+	printtree(&out, root, 0);
+	
+	Bprint(&out, "demux 2 removed:\n");
+	ipmuxremove(&root, f2copy);
+	printtree(&out, root, 0);
+}
+
+enum
+{
+	Tproto,
+	Tdata,
+	Tdst,
+	Tsrc,
+	Tifc,
+};
+
+char *ftname[] = 
+{
+[Tdata]	"data",
+[Tdst]	"dst",
+[Tsrc]	"src",
+[Tifc]	"ifc",
+};
+
+struct Ipmux
+{
+	Ipmux	*yes;
+	Ipmux	*no;
+	uchar	type;
+	ushort	len;		/* length in bytes of item to compare */
+	ushort	off;		/* offset of comparison */
+	int	n;		/* number of items val points to */
+	uchar	*val;
+	uchar	*mask;
+
+	Conv	*c;
+	int	ref;		/* so we can garbage collect */
+};
+
+/*
+ *  connection request is a semi separated list of filters
+ *  e.g. proto=17;dat[0:4]=11aa22bb;ifc=135.104.9.2
+ *
+ *  there's no protection against overlapping specs.
+ */
+static char*
+ipmuxconnect(Conv *c, char **argv, int argc)
+{
+	int n, proto;
+	char *field[10];
+	Ipmux *mux, *chain;
+	Fs *f;
+
+	f = c->p->f;
+
+	if(argc != 2)
+		return Ebadarg;
+
+	n = parsefields(argv[1], field, nelem(field), ";");
+	if(n <= 0)
+		return Ebadarg;
+
+	chain = nil; 
+	for(i = 0; i < n; i++){
+		mux = ipmuxparse(field[i]);
+		if(mux == nil){
+			ipmuxtreefree(chain);
+			return Ebadarg;
+		}
+		ipmuxchain(&chain, mux);
+	}
+
+	/* optimize the protocol into an array lookup */
+	if(chain->type != Tproto){
+		ipmuxtreefree(chain);
+		return "need proto rule";
+	}
+	mux = chain;
+	proto = mux->val;
+	chain = chain->yes;
+	ipmuxfree(mux);
+
+	/* save a copy of the chain so we can later remove it */
+	mux->conv = c;
+	mux = ipmuxcopy(chain);
+	*(Ipmux***)(c->ptcl) = chain;
+
+	/* add the chain to the protocol demultiplexor tree */
+	qlock(p);
+	f->t2m[proto] = ipmuxmerge(f->t2m[proto], mux);
+	qunlock(p);
+
+	Fsconnected(c, nil);
+	return nil;
+}
+
+static int
+ipmuxstate(Conv *c, char *state, int n)
+{
+	USED(c);
+	return snprint(state, n, "%s", "Datagram");
+}
+
+static void
+ipmuxcreate(Conv *c)
+{
+	c->rq = qopen(64*1024, 0, 0, c);
+	c->wq = qopen(64*1024, 0, 0, 0);
+	*(IPmux**)(c->ptcl) = nil;
+}
+
+static char*
+ipmuxannounce(Conv*, char**, int)
+{
+	return "ipmux does not support announce";
+}
+
+static void
+ipmuxclose(Conv *c)
+{
+	qclose(c->rq);
+	qclose(c->wq);
+	qclose(c->eq);
+	ipmove(c->laddr, IPnoaddr);
+	ipmove(c->raddr, IPnoaddr);
+	c->lport = 0;
+	c->rport = 0;
+
+	unlock(c);
+}
+
+/*
+ *  takes a fully formed ip packet and just passes it down
+ *  the stack
+ */
+static void
+ipmuxkick(Conv *c, int l)
+{
+}
+
+static void
+ipmuxiput(Proto *ipmux, uchar*, Block *bp)
+{
+}
+
+int
+ipmuxstats(Proto *ipmux, char *buf, int len)
+{
+	return 0;
+}
+
+void
+ipmuxinit(Fs *fs)
+{
+	Proto *ipmux;
+
+	ipmux = smalloc(sizeof(Proto));
+	ipmux->priv = smalloc(sizeof(GREpriv));
+	ipmux->name = "ipmux";
+	ipmux->kick = ipmuxkick;
+	ipmux->connect = ipmuxconnect;
+	ipmux->announce = ipmuxannounce;
+	ipmux->state = ipmuxstate;
+	ipmux->create = ipmuxcreate;
+	ipmux->close = ipmuxclose;
+	ipmux->rcv = ipmuxiput;
+	ipmux->ctl = nil;
+	ipmux->advise = nil;
+	ipmux->stats = ipmuxstats;
+	ipmux->ipproto = -1;
+	ipmux->nc = 64;
+	ipmux->ptclsize = sizeof(Ipmux*);
+
+	Fsproto(fs, ipmux);
+}
diff --git a/pc/pci.c b/pc/pci.c
index b7f6e4e90b6fae6862b41cde129e16f0bb9b44ab..4e0032215121df9789715a5968eef51480bfe153 100644
--- a/pc/pci.c
+++ b/pc/pci.c
@@ -205,7 +205,7 @@ pcicfginit(void)
 			list = &pciroot;
 			for(bno = 0; bno < 256; bno++){
 				bno = pciscan(bno, list);
-				while(*list && (*list)->link)
+				while(*list)
 					list = &(*list)->link;
 			}