X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/3a7639e545c0543bcec19c4321dd3ba397fbe6fa..2e63bc0ec11f2b041ee53e2ed986c9d50f135700:/print-openflow.c

diff --git a/print-openflow.c b/print-openflow.c
index 687b16d6..3b85dd7a 100644
--- a/print-openflow.c
+++ b/print-openflow.c
@@ -33,17 +33,16 @@
 /* \summary: version-independent OpenFlow printer */
 
 #ifdef HAVE_CONFIG_H
-#include "config.h"
+#include <config.h>
 #endif
 
-#include <netdissect-stdinc.h>
+#include "netdissect-stdinc.h"
 
 #include "netdissect.h"
 #include "extract.h"
 #include "openflow.h"
 #include "oui.h"
 
-static const char tstr[] = " [|openflow]";
 
 #define OF_VER_1_0    0x01
 
@@ -70,73 +69,90 @@ static void
 of_header_print(netdissect_options *ndo, const uint8_t version, const uint8_t type,
                       const uint16_t length, const uint32_t xid)
 {
-	ND_PRINT((ndo, "\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
-	       version, type, length, xid));
-}
-
-/* Print a single OpenFlow message. */
-static const u_char *
-of_header_body_print(netdissect_options *ndo, const u_char *cp, const u_char *ep)
-{
-	uint8_t version, type;
-	uint16_t length;
-	uint32_t xid;
-
-	if (ep < cp + OF_HEADER_LEN)
-		goto invalid;
-	/* version */
-	ND_TCHECK_1(cp);
-	version = EXTRACT_U_1(cp);
-	cp += 1;
-	/* type */
-	ND_TCHECK_1(cp);
-	type = EXTRACT_U_1(cp);
-	cp += 1;
-	/* length */
-	ND_TCHECK_2(cp);
-	length = EXTRACT_BE_U_2(cp);
-	cp += 2;
-	/* xid */
-	ND_TCHECK_4(cp);
-	xid = EXTRACT_BE_U_4(cp);
-	cp += 4;
-	/* Message length includes the header length and a message always includes
-	 * the basic header. A message length underrun fails decoding of the rest of
-	 * the current packet. At the same time, try decoding as much of the current
-	 * message as possible even when it does not end within the current TCP
-	 * segment. */
-	if (length < OF_HEADER_LEN) {
-		of_header_print(ndo, version, type, length, xid);
-		goto invalid;
-	}
-	/* Decode known protocol versions further without printing the header (the
-	 * type decoding is version-specific. */
-	switch (version) {
-	case OF_VER_1_0:
-		return of10_header_body_print(ndo, cp, ep, type, length, xid);
-	default:
-		of_header_print(ndo, version, type, length, xid);
-		ND_TCHECK2(*cp, length - OF_HEADER_LEN);
-		return cp + length - OF_HEADER_LEN; /* done with current message */
-	}
-
-invalid: /* fail current packet */
-	ND_PRINT((ndo, "%s", istr));
-	ND_TCHECK2(*cp, ep - cp);
-	return ep;
-trunc:
-	ND_PRINT((ndo, "%s", tstr));
-	return ep;
+	ND_PRINT("\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
+	       version, type, length, xid);
 }
 
 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
  * on a message boundary. */
 void
-openflow_print(netdissect_options *ndo, const u_char *cp, const u_int len)
+openflow_print(netdissect_options *ndo, const u_char *cp, u_int len)
 {
-	const u_char *ep = cp + len;
+	ndo->ndo_protocol = "openflow";
+	ND_PRINT(": OpenFlow");
+	while (len) {
+		/* Print a single OpenFlow message. */
+		uint8_t version, type;
+		uint16_t length;
+		uint32_t xid;
 
-	ND_PRINT((ndo, ": OpenFlow"));
-	while (cp < ep)
-		cp = of_header_body_print(ndo, cp, ep);
+		if (len < OF_HEADER_FIXLEN)
+			goto invalid;
+		/* version */
+		version = GET_U_1(cp);
+		OF_FWD(1);
+		/* type */
+		type = GET_U_1(cp);
+		OF_FWD(1);
+		/* length */
+		length = GET_BE_U_2(cp);
+		OF_FWD(2);
+		/* xid */
+		xid = GET_BE_U_4(cp);
+		OF_FWD(4);
+		/*
+		 * When a TCP packet can contain several protocol messages,
+		 * and at the same time a protocol message can span several
+		 * TCP packets, decoding an incomplete message at the end of
+		 * a TCP packet requires attention to detail in this loop.
+		 *
+		 * Message length includes the header length and a message
+		 * always includes the basic header. A message length underrun
+		 * fails decoding of the rest of the current packet. At the
+		 * same time, try decoding as much of the current message as
+		 * possible even when it does not end within the current TCP
+		 * segment.
+		 *
+		 * Specifically, to try to process the message body in this
+		 * iteration do NOT require the header "length" to be small
+		 * enough for the full declared OpenFlow message to fit into
+		 * the remainder of the declared TCP segment, same as the full
+		 * declared TCP segment is not required to fit into the
+		 * captured packet buffer.
+		 *
+		 * But DO require the same at the end of this iteration to
+		 * decrement "len" and to proceed to the next iteration.
+		 * (Ideally the declared TCP payload end will be at or after
+		 * the captured packet buffer end, but stay safe even when
+		 * that's somehow not the case.)
+		 */
+		if (length < OF_HEADER_FIXLEN) {
+			of_header_print(ndo, version, type, length, xid);
+			goto invalid;
+		}
+		/*
+		 * Decode known protocol versions further without printing the
+		 * header (the type decoding is version-specific).
+		 */
+		switch (version) {
+		case OF_VER_1_0:
+			of10_header_body_print(ndo, cp, type,
+			                       length - OF_HEADER_FIXLEN, xid);
+			break;
+		default:
+			of_header_print(ndo, version, type, length, xid);
+			ND_TCHECK_LEN(cp, length - OF_HEADER_FIXLEN);
+		}
+		if (length - OF_HEADER_FIXLEN > len)
+			break;
+		OF_FWD(length - OF_HEADER_FIXLEN);
+	} /* while (len) */
+	return;
+
+invalid: /* fail the current packet */
+	nd_print_invalid(ndo);
+	ND_TCHECK_LEN(cp, len);
+	return;
+trunc:
+	nd_trunc(ndo);
 }