PPP options in LCP, IPCP, etc. are like IP and TCP options - one octet

of option code, one octet of length (which includes the two option code
and length bytes), followed by 0 or more octets of option data, with
some options being fixed-length and some being variable-length.  Put
some stuff from the PPP control protocol option parsing code into the
IP-and-TCP option parsing code, and use the latter instead of the
former.

(That code might also be usable for CDP as well, with some stuff added
to it.)

Shuffle the arguments to "dissect_ip_tcp_options()" to resemble those of
various other dissectors (i.e., with the "proto_tree *" at the end).

Add in code to dissect a pile of PPP options documented in various RFCs.

svn path=/trunk/; revision=601

1 files changed, 46 insertions, 35 deletions

diff --git a/packet-ip.c b/packet-ip.c
index a67ef6b4a9..db4d4305d7 100644
--- a/packet-ip.c
+++ b/packet-ip.c
@@ -1,7 +1,7 @@
 /* packet-ip.c
  * Routines for IP and miscellaneous IP protocol packet disassembly
  *
- * $Id: packet-ip.c,v 1.42 1999/08/28 03:56:03 gram Exp $
+ * $Id: packet-ip.c,v 1.43 1999/08/28 08:31:26 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@zing.org>
@@ -259,8 +259,8 @@ capture_ip(const u_char *pd, int offset, guint32 cap_len, packet_counts *ld) {
 }
 
 static void
-dissect_ipopt_security(proto_tree *opt_tree, const char *name,
-    const u_char *opd, int offset, guint optlen)
+dissect_ipopt_security(const ip_tcp_opt *optp, const u_char *opd, int offset,
+			guint optlen, proto_tree *opt_tree)
 {
   proto_tree *field_tree = NULL;
   proto_item *tf;
@@ -283,8 +283,8 @@ dissect_ipopt_security(proto_tree *opt_tree, const char *name,
     {IPSEC_RESERVED8,    "Reserved"    },
     {0,                  NULL          } };
 
-  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s:", name);
-  field_tree = proto_item_add_subtree(tf, ETT_IP_OPTION_SEC);
+  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s:", optp->name);
+  field_tree = proto_item_add_subtree(tf, optp->subtree_index);
   offset += 2;
 
   val = pntohs(opd);
@@ -309,8 +309,8 @@ dissect_ipopt_security(proto_tree *opt_tree, const char *name,
 }
 
 static void
-dissect_ipopt_route(proto_tree *opt_tree, const char *name,
-    const u_char *opd, int offset, guint optlen)
+dissect_ipopt_route(const ip_tcp_opt *optp, const u_char *opd, int offset,
+			guint optlen, proto_tree *opt_tree)
 {
   proto_tree *field_tree = NULL;
   proto_item *tf;
@@ -318,9 +318,9 @@ dissect_ipopt_route(proto_tree *opt_tree, const char *name,
   int optoffset = 0;
   struct in_addr addr;
 
-  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s (%d bytes)", name,
-              optlen);
-  field_tree = proto_item_add_subtree(tf, ETT_IP_OPTION_ROUTE);
+  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s (%d bytes)",
+				optp->name, optlen);
+  field_tree = proto_item_add_subtree(tf, optp->subtree_index);
 
   optoffset += 2;	/* skip past type and length */
   optlen -= 2;		/* subtract size of type and length */
@@ -356,17 +356,17 @@ dissect_ipopt_route(proto_tree *opt_tree, const char *name,
 }
 
 static void
-dissect_ipopt_sid(proto_tree *opt_tree, const char *name, const u_char *opd,
-    int offset, guint optlen)
+dissect_ipopt_sid(const ip_tcp_opt *optp, const u_char *opd, int offset,
+			guint optlen, proto_tree *opt_tree)
 {
   proto_tree_add_text(opt_tree, offset,      optlen,
-    "%s: %d", name, pntohs(opd));
+    "%s: %d", optp->name, pntohs(opd));
   return;
 }
 
 static void
-dissect_ipopt_timestamp(proto_tree *opt_tree, const char *name, const u_char *opd,
-    int offset, guint optlen)
+dissect_ipopt_timestamp(const ip_tcp_opt *optp, const u_char *opd,
+    int offset, guint optlen, proto_tree *opt_tree)
 {
   proto_tree *field_tree = NULL;
   proto_item *tf;
@@ -382,8 +382,8 @@ dissect_ipopt_timestamp(proto_tree *opt_tree, const char *name, const u_char *op
   struct in_addr addr;
   guint ts;
 
-  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s:", name);
-  field_tree = proto_item_add_subtree(tf, ETT_IP_OPTION_TIMESTAMP);
+  tf = proto_tree_add_text(opt_tree, offset,      optlen, "%s:", optp->name);
+  field_tree = proto_item_add_subtree(tf, optp->subtree_index);
 
   optoffset += 2;	/* skip past type and length */
   optlen -= 2;		/* subtract size of type and length */
@@ -450,10 +450,11 @@ dissect_ipopt_timestamp(proto_tree *opt_tree, const char *name, const u_char *op
   }
 }
 
-static ip_tcp_opt ipopts[] = {
+static const ip_tcp_opt ipopts[] = {
   {
     IPOPT_END,
     "EOL",
+    -1,
     NO_LENGTH,
     0,
     NULL,
@@ -461,6 +462,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_NOOP,
     "NOP",
+    -1,
     NO_LENGTH,
     0,
     NULL,
@@ -468,6 +470,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_SEC,
     "Security",
+    ETT_IP_OPTION_SEC,
     FIXED_LENGTH,
     IPOLEN_SEC,
     dissect_ipopt_security
@@ -475,6 +478,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_SSRR,
     "Strict source route",
+    ETT_IP_OPTION_ROUTE,
     VARIABLE_LENGTH,
     IPOLEN_SSRR_MIN,
     dissect_ipopt_route
@@ -482,6 +486,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_LSRR,
     "Loose source route",
+    ETT_IP_OPTION_ROUTE,
     VARIABLE_LENGTH,
     IPOLEN_LSRR_MIN,
     dissect_ipopt_route
@@ -489,6 +494,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_RR,
     "Record route",
+    ETT_IP_OPTION_ROUTE,
     VARIABLE_LENGTH,
     IPOLEN_RR_MIN,
     dissect_ipopt_route
@@ -496,6 +502,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_SID,
     "Stream identifier",
+    -1,
     FIXED_LENGTH,
     IPOLEN_SID,
     dissect_ipopt_sid
@@ -503,6 +510,7 @@ static ip_tcp_opt ipopts[] = {
   {
     IPOPT_TIMESTAMP,
     "Time stamp",
+    ETT_IP_OPTION_TIMESTAMP,
     VARIABLE_LENGTH,
     IPOLEN_TIMESTAMP_MIN,
     dissect_ipopt_timestamp
@@ -513,12 +521,13 @@ static ip_tcp_opt ipopts[] = {
 
 /* Dissect the IP or TCP options in a packet. */
 void
-dissect_ip_tcp_options(proto_tree *opt_tree, const u_char *opd, int offset,
-    guint length, ip_tcp_opt *opttab, int nopts, int eol)
+dissect_ip_tcp_options(const u_char *opd, int offset, guint length,
+			const ip_tcp_opt *opttab, int nopts, int eol,
+			proto_tree *opt_tree)
 {
-  u_char      opt;
-  ip_tcp_opt *optp;
-  guint       len;
+  u_char            opt;
+  const ip_tcp_opt *optp;
+  guint             len;
 
   while (length > 0) {
     opt = *opd++;
@@ -527,7 +536,7 @@ dissect_ip_tcp_options(proto_tree *opt_tree, const u_char *opd, int offset,
         break;
     }
     if (optp == &opttab[nopts]) {
-      proto_tree_add_text(opt_tree, offset,      1, "Unknown");
+      proto_tree_add_text(opt_tree, offset,      1, "Unknown (0x%02x)", opt);
       /* We don't know how long this option is, so we don't know how much
          of it to skip, so we just bail. */
       return;
@@ -539,7 +548,7 @@ dissect_ip_tcp_options(proto_tree *opt_tree, const u_char *opd, int offset,
         /* Bogus - packet must at least include option code byte and
            length byte! */
         proto_tree_add_text(opt_tree, offset,      1,
-              "%s (length byte past end of header)", optp->name);
+              "%s (length byte past end of options)", optp->name);
         return;
       }
       len = *opd++;  /* total including type, len */
@@ -548,34 +557,36 @@ dissect_ip_tcp_options(proto_tree *opt_tree, const u_char *opd, int offset,
         /* Bogus - option length is too short to include option code and
            option length. */
         proto_tree_add_text(opt_tree, offset,      2,
-              "%s (with too-short option length = %u bytes)", optp->name, 2);
+              "%s (with too-short option length = %u byte%s)", optp->name,
+              plurality(len, "", "s"));
         return;
       } else if (len - 2 > length) {
         /* Bogus - option goes past the end of the header. */
         proto_tree_add_text(opt_tree, offset,      length,
-              "%s (option goes past end of header)", optp->name);
+              "%s (option length = %u byte%s says option goes past end of options)",
+	      optp->name, len, plurality(len, "", "s"));
         return;
       } else if (optp->len_type == FIXED_LENGTH && len != optp->optlen) {
         /* Bogus - option length isn't what it's supposed to be for this
            option. */
         proto_tree_add_text(opt_tree, offset,      len,
-              "%s (with option length = %u bytes; should be %u)", optp->name,
-              len, optp->optlen);
+              "%s (with option length = %u byte%s; should be %u)", optp->name,
+              len, plurality(len, "", "s"), optp->optlen);
         return;
       } else if (optp->len_type == VARIABLE_LENGTH && len < optp->optlen) {
         /* Bogus - option length is less than what it's supposed to be for
            this option. */
         proto_tree_add_text(opt_tree, offset,      len,
-              "%s (with option length = %u bytes; should be >= %u)", optp->name,
-              len, optp->optlen);
+              "%s (with option length = %u byte%s; should be >= %u)", optp->name,
+              len, plurality(len, "", "s"), optp->optlen);
         return;
       } else {
         if (optp->dissect != NULL) {
           /* Option has a dissector. */
-          (*optp->dissect)(opt_tree, optp->name, opd, offset, len);
+          (*optp->dissect)(optp, opd, offset,      len, opt_tree);
         } else {
           /* Option has no data, hence no dissector. */
-          proto_tree_add_text(opt_tree, offset,      len, "%s", optp->name);
+          proto_tree_add_text(opt_tree, offset,    len, "%s", optp->name);
         }
         len -= 2;	/* subtract size of type and length */
         offset += 2 + len;
@@ -767,8 +778,8 @@ dissect_ip(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) {
       tf = proto_tree_add_text(ip_tree, offset +  20, optlen,
         "Options: (%d bytes)", optlen);
       field_tree = proto_item_add_subtree(tf, ETT_IP_OPTIONS);
-      dissect_ip_tcp_options(field_tree, &pd[offset + 20], offset + 20, optlen,
-         ipopts, N_IP_OPTS, IPOPT_END);
+      dissect_ip_tcp_options(&pd[offset + 20], offset + 20, optlen,
+         ipopts, N_IP_OPTS, IPOPT_END, field_tree);
     }
   }