X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/e070cf232ffadbdbbca68b132ef369675890e566..1fb50928ce27360c1c987312774f686b23c69b51:/print-sll.c

diff --git a/print-sll.c b/print-sll.c
index 2cd90f72..6148569e 100644
--- a/print-sll.c
+++ b/print-sll.c
@@ -18,91 +18,189 @@
  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
-#ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-sll.c,v 1.10 2002-12-18 08:53:24 guy Exp $ (LBL)";
-#endif
+
+/* \summary: Linux cooked sockets capture printer */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
+#include <netdissect-stdinc.h>
 
-#include <stdio.h>
-#include <string.h>
-#include <pcap.h>
-
-#include "interface.h"
+#include "netdissect.h"
 #include "addrtoname.h"
 #include "ethertype.h"
+#include "extract.h"
 
 #include "ether.h"
-#include "sll.h"
 
-static inline void
-sll_print(register const struct sll_header *sllp, u_int length)
-{
-	u_short halen;
+/*
+ * For captures on Linux cooked sockets, we construct a fake header
+ * that includes:
+ *
+ *	a 2-byte "packet type" which is one of:
+ *
+ *		LINUX_SLL_HOST		packet was sent to us
+ *		LINUX_SLL_BROADCAST	packet was broadcast
+ *		LINUX_SLL_MULTICAST	packet was multicast
+ *		LINUX_SLL_OTHERHOST	packet was sent to somebody else
+ *		LINUX_SLL_OUTGOING	packet was sent *by* us;
+ *
+ *	a 2-byte Ethernet protocol field;
+ *
+ *	a 2-byte link-layer type;
+ *
+ *	a 2-byte link-layer address length;
+ *
+ *	an 8-byte source link-layer address, whose actual length is
+ *	specified by the previous value.
+ *
+ * All fields except for the link-layer address are in network byte order.
+ *
+ * DO NOT change the layout of this structure, or change any of the
+ * LINUX_SLL_ values below.  If you must change the link-layer header
+ * for a "cooked" Linux capture, introduce a new DLT_ type (ask
+ * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
+ * a value that collides with a value already being used), and use the
+ * new header in captures of that type, so that programs that can
+ * handle DLT_LINUX_SLL captures will continue to handle them correctly
+ * without any change, and so that capture files with different headers
+ * can be told apart and programs that read them can dissect the
+ * packets in them.
+ *
+ * This structure, and the #defines below, must be the same in the
+ * libpcap and tcpdump versions of "sll.h".
+ */
 
-	switch (ntohs(sllp->sll_pkttype)) {
+/*
+ * A DLT_LINUX_SLL fake link-layer header.
+ */
+#define SLL_HDR_LEN	16		/* total header length */
+#define SLL_ADDRLEN	8		/* length of address field */
 
-	case LINUX_SLL_HOST:
-		(void)printf("< ");
-		break;
+struct sll_header {
+	uint16_t	sll_pkttype;	/* packet type */
+	uint16_t	sll_hatype;	/* link-layer address type */
+	uint16_t	sll_halen;	/* link-layer address length */
+	uint8_t		sll_addr[SLL_ADDRLEN];	/* link-layer address */
+	uint16_t	sll_protocol;	/* protocol */
+};
 
-	case LINUX_SLL_BROADCAST:
-		(void)printf("B ");
-		break;
+/*
+ * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
+ * PACKET_ values on Linux, but are defined here so that they're
+ * available even on systems other than Linux, and so that they
+ * don't change even if the PACKET_ values change.
+ */
+#define LINUX_SLL_HOST		0
+#define LINUX_SLL_BROADCAST	1
+#define LINUX_SLL_MULTICAST	2
+#define LINUX_SLL_OTHERHOST	3
+#define LINUX_SLL_OUTGOING	4
 
-	case LINUX_SLL_MULTICAST:
-		(void)printf("M ");
-		break;
+/*
+ * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
+ * ETH_P_ values on Linux, but are defined here so that they're
+ * available even on systems other than Linux.  We assume, for now,
+ * that the ETH_P_ values won't change in Linux; if they do, then:
+ *
+ *	if we don't translate them in "pcap-linux.c", capture files
+ *	won't necessarily be readable if captured on a system that
+ *	defines ETH_P_ values that don't match these values;
+ *
+ *	if we do translate them in "pcap-linux.c", that makes life
+ *	unpleasant for the BPF code generator, as the values you test
+ *	for in the kernel aren't the values that you test for when
+ *	reading a capture file, so the fixup code run on BPF programs
+ *	handed to the kernel ends up having to do more work.
+ *
+ * Add other values here as necessary, for handling packet types that
+ * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
+ * in the Linux "if_ether.h" will, I suspect, actually show up in
+ * captures.)
+ */
+#define LINUX_SLL_P_802_3	0x0001	/* Novell 802.3 frames without 802.2 LLC header */
+#define LINUX_SLL_P_802_2	0x0004	/* 802.2 frames (not D/I/X Ethernet) */
 
-	case LINUX_SLL_OTHERHOST:
-		(void)printf("P ");
-		break;
+static const struct tok sll_pkttype_values[] = {
+    { LINUX_SLL_HOST, "In" },
+    { LINUX_SLL_BROADCAST, "B" },
+    { LINUX_SLL_MULTICAST, "M" },
+    { LINUX_SLL_OTHERHOST, "P" },
+    { LINUX_SLL_OUTGOING, "Out" },
+    { 0, NULL}
+};
 
-	case LINUX_SLL_OUTGOING:
-		(void)printf("> ");
-		break;
+static inline void
+sll_print(netdissect_options *ndo, register const struct sll_header *sllp, u_int length)
+{
+	u_short ether_type;
 
-	default:
-		(void)printf("? ");
-		break;
-	}
+        ND_PRINT((ndo, "%3s ",tok2str(sll_pkttype_values,"?",EXTRACT_16BITS(&sllp->sll_pkttype))));
 
 	/*
 	 * XXX - check the link-layer address type value?
 	 * For now, we just assume 6 means Ethernet.
 	 * XXX - print others as strings of hex?
 	 */
-	halen = ntohs(sllp->sll_halen);
-	if (halen == 6)
-		(void)printf("%s ", etheraddr_string(sllp->sll_addr));
+	if (EXTRACT_16BITS(&sllp->sll_halen) == 6)
+		ND_PRINT((ndo, "%s ", etheraddr_string(ndo, sllp->sll_addr)));
+
+	if (!ndo->ndo_qflag) {
+		ether_type = EXTRACT_16BITS(&sllp->sll_protocol);
+
+		if (ether_type <= ETHERMTU) {
+			/*
+			 * Not an Ethernet type; what type is it?
+			 */
+			switch (ether_type) {
+
+			case LINUX_SLL_P_802_3:
+				/*
+				 * Ethernet_802.3 IPX frame.
+				 */
+				ND_PRINT((ndo, "802.3"));
+				break;
 
-	if (!qflag)
-		(void)printf("%s ", etherproto_string(sllp->sll_protocol));
-	(void)printf("%d: ", length);
+			case LINUX_SLL_P_802_2:
+				/*
+				 * 802.2.
+				 */
+				ND_PRINT((ndo, "802.2"));
+				break;
+
+			default:
+				/*
+				 * What is it?
+				 */
+				ND_PRINT((ndo, "ethertype Unknown (0x%04x)",
+				    ether_type));
+				break;
+			}
+		} else {
+			ND_PRINT((ndo, "ethertype %s (0x%04x)",
+			    tok2str(ethertype_values, "Unknown", ether_type),
+			    ether_type));
+		}
+		ND_PRINT((ndo, ", length %u: ", length));
+	}
 }
 
 /*
  * This is the top level routine of the printer.  'p' points to the
  * Linux "cooked capture" header of the packet, 'h->ts' is the timestamp,
- * 'h->length' is the length of the packet off the wire, and 'h->caplen'
+ * 'h->len' is the length of the packet off the wire, and 'h->caplen'
  * is the number of bytes actually captured.
  */
-void
-sll_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
+u_int
+sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char *p)
 {
 	u_int caplen = h->caplen;
 	u_int length = h->len;
 	register const struct sll_header *sllp;
 	u_short ether_type;
-	u_short extracted_ethertype;
-
-	++infodelay;
-	ts_print(&h->ts);
+	int llc_hdrlen;
+	u_int hdrlen;
 
 	if (caplen < SLL_HDR_LEN) {
 		/*
@@ -110,33 +208,30 @@ sll_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
 		 * adds this many bytes of header to every packet in a
 		 * cooked socket capture.
 		 */
-		printf("[|sll]");
-		goto out;
+		ND_PRINT((ndo, "[|sll]"));
+		return (caplen);
 	}
 
 	sllp = (const struct sll_header *)p;
 
-	if (eflag)
-		sll_print(sllp, length);
+	if (ndo->ndo_eflag)
+		sll_print(ndo, sllp, length);
 
 	/*
-	 * Some printers want to check that they're not walking off the
-	 * end of the packet.
-	 * Rather than pass it all the way down, we set this global.
+	 * Go past the cooked-mode header.
 	 */
-	snapend = p + caplen;
-
 	length -= SLL_HDR_LEN;
 	caplen -= SLL_HDR_LEN;
 	p += SLL_HDR_LEN;
+	hdrlen = SLL_HDR_LEN;
 
-	ether_type = ntohs(sllp->sll_protocol);
+	ether_type = EXTRACT_16BITS(&sllp->sll_protocol);
 
+recurse:
 	/*
 	 * Is it (gag) an 802.3 encapsulation, or some non-Ethernet
 	 * packet type?
 	 */
-	extracted_ethertype = 0;
 	if (ether_type <= ETHERMTU) {
 		/*
 		 * Yes - what type is it?
@@ -147,7 +242,7 @@ sll_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
 			/*
 			 * Ethernet_802.3 IPX frame.
 			 */
-			ipx_print(p, length);
+			ipx_print(ndo, p, length);
 			break;
 
 		case LINUX_SLL_P_802_2:
@@ -155,37 +250,61 @@ sll_if_print(u_char *user _U_, const struct pcap_pkthdr *h, const u_char *p)
 			 * 802.2.
 			 * Try to print the LLC-layer header & higher layers.
 			 */
-			if (llc_print(p, length, caplen, NULL, NULL,
-			    &extracted_ethertype) == 0)
+			llc_hdrlen = llc_print(ndo, p, length, caplen, NULL, NULL);
+			if (llc_hdrlen < 0)
 				goto unknown;	/* unknown LLC type */
+			hdrlen += llc_hdrlen;
 			break;
 
 		default:
+			/*FALLTHROUGH*/
+
 		unknown:
-			/* ether_type not known, print raw packet */
-			if (!eflag)
-				sll_print(sllp, length + SLL_HDR_LEN);
-			if (extracted_ethertype) {
-				printf("(LLC %s) ",
-			       etherproto_string(htons(extracted_ethertype)));
-			}
-			if (!xflag && !qflag)
-				default_print(p, caplen);
+			/* packet type not known, print raw packet */
+			if (!ndo->ndo_suppress_default_print)
+				ND_DEFAULTPRINT(p, caplen);
 			break;
 		}
-	} else if (ether_encap_print(ether_type, p, length, caplen,
-	    &extracted_ethertype) == 0) {
-		/* ether_type not known, print raw packet */
-		if (!eflag)
-			sll_print(sllp, length + SLL_HDR_LEN);
-		if (!xflag && !qflag)
-			default_print(p, caplen);
+	} else if (ether_type == ETHERTYPE_8021Q) {
+		/*
+		 * Print VLAN information, and then go back and process
+		 * the enclosed type field.
+		 */
+		if (caplen < 4) {
+			ND_PRINT((ndo, "[|vlan]"));
+			return (hdrlen + caplen);
+		}
+		if (length < 4) {
+			ND_PRINT((ndo, "[|vlan]"));
+			return (hdrlen + length);
+		}
+	        if (ndo->ndo_eflag) {
+	        	uint16_t tag = EXTRACT_16BITS(p);
+
+			ND_PRINT((ndo, "%s, ", ieee8021q_tci_string(tag)));
+		}
+
+		ether_type = EXTRACT_16BITS(p + 2);
+		if (ether_type <= ETHERMTU)
+			ether_type = LINUX_SLL_P_802_2;
+		if (!ndo->ndo_qflag) {
+			ND_PRINT((ndo, "ethertype %s, ",
+			    tok2str(ethertype_values, "Unknown", ether_type)));
+		}
+		p += 4;
+		length -= 4;
+		caplen -= 4;
+		hdrlen += 4;
+		goto recurse;
+	} else {
+		if (ethertype_print(ndo, ether_type, p, length, caplen, NULL, NULL) == 0) {
+			/* ether_type not known, print raw packet */
+			if (!ndo->ndo_eflag)
+				sll_print(ndo, sllp, length + SLL_HDR_LEN);
+			if (!ndo->ndo_suppress_default_print)
+				ND_DEFAULTPRINT(p, caplen);
+		}
 	}
-	if (xflag)
-		default_print(p, caplen);
- out:
-	putchar('\n');
-	--infodelay;
-	if (infoprint)
-		info(0);
+
+	return (hdrlen);
 }