Avoiding conditional directives that break statements

[tcpdump] / print-udld.c

diff --git a/print-udld.c b/print-udld.c
index a5488dda451ff3f56f70b6614d927e9b2bc29138..0dc10d3c62a9c4d70a97a2f798f183ad6beebe1e 100644 (file)
--- a/print-udld.c
+++ b/print-udld.c
@@ -12,8 +12,7 @@
  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE.
  *
- * UNIDIRECTIONAL LINK DETECTION (UDLD) as per 
- * http://www.ietf.org/internet-drafts/draft-foschiano-udld-02.txt
+ * UNIDIRECTIONAL LINK DETECTION (UDLD) as per RFC5171
  *
  * Original code by Carles Kishimoto <[email protected]>
  */
@@ -22,15 +21,13 @@
 #include "config.h"
 #endif
 
-#include <tcpdump-stdinc.h>
+#include <netdissect-stdinc.h>
 
-#include <stdio.h>
-#include <string.h>
+#include "netdissect.h"
+#include "extract.h"
 
-#include "interface.h"
-#include "addrtoname.h"
-#include "extract.h"           
-#include "nlpid.h"
+static const char tstr[] = " [|udld]";
+static const char istr[] = " (invalid)";
 
 #define UDLD_HEADER_LEN                        4
 #define UDLD_DEVICE_ID_TLV             0x0001
@@ -41,7 +38,7 @@
 #define UDLD_DEVICE_NAME_TLV           0x0006
 #define UDLD_SEQ_NUMBER_TLV            0x0007
 
-static struct tok udld_tlv_values[] = {
+static const struct tok udld_tlv_values[] = {
     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
     { UDLD_ECHO_TLV, "Echo TLV"},
@@ -52,7 +49,7 @@ static struct tok udld_tlv_values[] = {
     { 0, NULL}
 };
 
-static struct tok udld_code_values[] = {
+static const struct tok udld_code_values[] = {
     { 0x00, "Reserved"},
     { 0x01, "Probe message"},
     { 0x02, "Echo message"},
@@ -60,30 +57,43 @@ static struct tok udld_code_values[] = {
     { 0, NULL}
 };
 
-static struct tok udld_flags_values[] = {
+static const struct tok udld_flags_values[] = {
     { 0x00, "RT"},
     { 0x01, "RSY"},
     { 0, NULL}
 };
 
 /*
+ * UDLD's Protocol Data Unit format:
  *
- * 0                   1                   2                   3 
- * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
- * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
- * | Ver | Opcode  |     Flags     |           Checksum            | 
- * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
- * |               List of TLVs (variable length list)             | 
- * |                              ...                              | 
- * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Ver | Opcode  |     Flags     |           Checksum            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |               List of TLVs (variable length list)             |
+ * |                              ...                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *
+ * TLV format:
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |             TYPE              |            LENGTH             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                             VALUE                             |
+ * |                              ...                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * LENGTH: Length in bytes of the Type, Length, and Value fields.
  */
 
-#define        UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5) 
-#define        UDLD_EXTRACT_OPCODE(x) ((x)&0x1f) 
+#define        UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
+#define        UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
 
 void
-udld_print (const u_char *pptr, u_int length)
+udld_print (netdissect_options *ndo, const u_char *pptr, u_int length)
 {
     int code, type, len;
     const u_char *tptr;
@@ -91,78 +101,92 @@ udld_print (const u_char *pptr, u_int length)
     if (length < UDLD_HEADER_LEN)
         goto trunc;
 
-    tptr = pptr; 
+    tptr = pptr;
 
-    if (!TTEST2(*tptr, UDLD_HEADER_LEN))       
-       goto trunc;
+    ND_TCHECK2(*tptr, UDLD_HEADER_LEN);
 
     code = UDLD_EXTRACT_OPCODE(*tptr);
 
-    printf("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u", 
+    ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
            UDLD_EXTRACT_VERSION(*tptr),
            tok2str(udld_code_values, "Reserved", code),
            code,
            bittok2str(udld_flags_values, "none", *(tptr+1)),
            *(tptr+1),
-           length);
+           length));
 
     /*
      * In non-verbose mode, just print version and opcode type
      */
-    if (vflag < 1) {
+    if (ndo->ndo_vflag < 1) {
        return;
     }
 
-    printf("\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2));
+    ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2)));
 
     tptr += UDLD_HEADER_LEN;
 
     while (tptr < (pptr+length)) {
 
-        if (!TTEST2(*tptr, 4)) 
-            goto trunc;
-
+        ND_TCHECK2(*tptr, 4);
        type = EXTRACT_16BITS(tptr);
-        len  = EXTRACT_16BITS(tptr+2); 
-        len -= 4;
-        tptr += 4;
+        len  = EXTRACT_16BITS(tptr+2);
+
+        ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
+               tok2str(udld_tlv_values, "Unknown", type),
+               type, len));
+
+        if (type == 0)
+            goto invalid;
 
         /* infinite loop check */
-        if (type == 0 || len == 0) {
-            return;
-        }
+        if (len <= 4)
+            goto invalid;
 
-        printf("\n\t%s (0x%04x) TLV, length %u",
-               tok2str(udld_tlv_values, "Unknown", type),
-               type, len);
+        len -= 4;
+        tptr += 4;
+
+        ND_TCHECK2(*tptr, len);
 
         switch (type) {
         case UDLD_DEVICE_ID_TLV:
         case UDLD_PORT_ID_TLV:
+        case UDLD_DEVICE_NAME_TLV:
+            ND_PRINT((ndo, ", "));
+            fn_printzp(ndo, tptr, len, NULL);
+            break;
+
         case UDLD_ECHO_TLV:
-        case UDLD_DEVICE_NAME_TLV: 
-            printf(", %s", tptr);
+            ND_PRINT((ndo, ", "));
+            (void)fn_printn(ndo, tptr, len, NULL);
             break;
 
-        case UDLD_MESSAGE_INTERVAL_TLV: 
+        case UDLD_MESSAGE_INTERVAL_TLV:
         case UDLD_TIMEOUT_INTERVAL_TLV:
-            printf(", %us", (*tptr));
+            if (len != 1)
+                goto invalid;
+            ND_PRINT((ndo, ", %us", (*tptr)));
             break;
 
         case UDLD_SEQ_NUMBER_TLV:
-            printf(", %u", EXTRACT_32BITS(tptr));
+            if (len != 4)
+                goto invalid;
+            ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr)));
             break;
 
         default:
             break;
-        }      
+        }
         tptr += len;
     }
 
     return;
 
- trunc:
-    printf("[|udld]");
+invalid:
+    ND_PRINT((ndo, "%s", istr));
+    return;
+trunc:
+    ND_PRINT((ndo, "%s", tstr));
 }
 
 /*