1 files changed, 173 insertions, 0 deletions
diff --git a/src/cmd/ip/snoopy/llc.c b/src/cmd/ip/snoopy/llc.c
new file mode 100644
index 00000000..bbc21986
--- /dev/null
+++ b/src/cmd/ip/snoopy/llc.c
@@ -0,0 +1,173 @@
+/* 
+ * LLC.  Only enough to dispatch to SNAP and IP.
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <ip.h>
+#include "dat.h"
+#include "protos.h"
+
+enum
+{
+	UFmt = 3,
+	Gsap = 1,
+	IG = 1,
+	SFmt = 1,
+	UPoll = 0x10,
+	IsPoll = 0x100,
+	XidFi = 0x81,
+	
+	SapNull = 0,
+	SapGlobal = 0xff,
+	Sap8021BI = 0x02,
+	Sap8021BG = 0x03,
+	SapSNA = 0x04,
+	SapIP = 0x06,
+	SapProwayNM = 0x0e,
+	Sap8021D = 0x42,
+	SapRS511 = 0x4e,
+	SapISO8208 = 0x7e,
+	SapProway = 0x8e,
+	SapSnap = 0xaa,
+	SapIpx = 0xe0,
+	SapNetbeui = 0xf0,
+	SapIsons = 0xfe,
+};
+
+static Mux p_mux[] =
+{
+// Linux gives llc -> snap not llc -> ip.
+// If we don't tell snoopy about llc -> ip, then the default patterns
+// like snoopy -h radiotap -f dns work better.
+//	{ "ip", SapIP },	
+	{ "snap", SapSnap },
+	{ 0 }
+};
+
+typedef struct Hdr Hdr;
+struct Hdr
+{
+	uchar dsap;
+	uchar ssap;
+	uchar dsapf;
+	uchar ssapf;
+	ushort ctl;
+	uchar isu;
+	int hdrlen;
+};
+
+static int
+unpackhdr(uchar *p, uchar *ep, Hdr *h)
+{
+	if(p+3 > ep)
+		return -1;
+	h->dsapf = p[0];
+	h->dsap = h->dsapf & ~IG;
+	h->ssapf = p[1];
+	h->ssap = h->ssapf & ~Gsap;
+	h->ctl = p[2];
+	h->hdrlen = 3;
+	if((h->ctl&UFmt) == UFmt)
+		h->isu = 1;
+	else{
+		if(p+4 > ep)
+			return -1;
+		h->hdrlen = 4;
+		h->ctl = LittleS(p+2);
+	}
+	return 0;
+}
+
+enum
+{
+	Ossap,
+	Odsap,
+	Ot,
+};
+
+static Field p_fields[] =
+{
+	{ "ssap",	Fnum,	Ossap,	"ssap" },
+	{ "dsap",	Fnum,	Odsap,	"dsap" },
+	{ 0 }
+};
+
+static void
+p_compile(Filter *f)
+{
+	Mux *m;
+
+	if(f->op == '='){
+		compile_cmp(llc.name, f, p_fields);
+		return;
+	}
+	for(m = p_mux; m->name != nil; m++){
+		if(strcmp(f->s, m->name) == 0){
+			f->pr = m->pr;
+			f->ulv = m->val;
+			f->subop = Ot;
+			return;
+		}
+	}
+	sysfatal("unknown llc field or protocol: %s", f->s);
+}
+
+static int
+p_filter(Filter *f, Msg *m)
+{
+	Hdr h;
+
+	memset(&h, 0, sizeof h);
+	if(unpackhdr(m->ps, m->pe, &h) < 0)
+		return 0;
+	m->ps += h.hdrlen;
+
+	switch(f->subop){
+	case Ossap:
+		return f->ulv == h.ssap;
+	case Odsap:
+		return f->ulv == h.dsap;
+	case Ot:
+		return f->ulv == h.ssap && f->ulv == h.dsap;
+	}
+	return 0;
+}
+
+static int
+p_seprint(Msg *m)
+{
+	Hdr h;
+	
+	memset(&h, 0, sizeof h);
+	if(unpackhdr(m->ps, m->pe, &h) < 0)
+		return -1;
+
+	m->pr = &dump;
+	m->p = seprint(m->p, m->e, "ssap=%02x dsap=%02x ctl=%04x", h.ssap, h.dsap, h.ctl);
+	m->ps += h.hdrlen;
+	m->pr = &dump;
+	if(h.ssap == h.dsap){
+		switch(h.ssap){
+		case SapIP:
+			m->pr = &ip;
+			break;
+		case SapSnap:
+			m->pr = &snap;
+			break;
+		}
+	}	
+	return 0;
+}
+
+Proto llc =
+{
+	"llc",
+	p_compile,
+	p_filter,
+	p_seprint,
+	p_mux,
+	nil,
+	nil,
+	defaultframer
+};