hi all,
pls find attached a patch that stops TLV processing
at the boundary indicated in the pdu_len field
in the IS-IS header;
this stops tcpdump from printing a lot of bogus
TLVs when the interface driver does not correctly
report the frame-length;
/hannes
Index: print-isoclns.c
===================================================================
RCS file: /tcpdump/master/tcpdump/print-isoclns.c,v
retrieving revision 1.33
diff -u -r1.33 print-isoclns.c
--- print-isoclns.c 2001/12/09 03:43:22 1.33
+++ print-isoclns.c 2001/12/13 07:36:51
@@ -226,7 +226,7 @@
u_char circuit_type;
u_char source_id[SYSTEM_ID_LEN];
u_char holding_time[2];
- u_char packet_len[2];
+ u_char pdu_len[2];
u_char priority;
u_char lan_id[SYSTEM_ID_LEN+1];
};
@@ -235,7 +235,7 @@
u_char circuit_type;
u_char source_id[SYSTEM_ID_LEN];
u_char holding_time[2];
- u_char packet_len[2];
+ u_char pdu_len[2];
u_char circuit_id;
};
@@ -677,7 +677,7 @@
u_char pdu_type, max_area, type, len, tmp, alen, subl, subt, tslen, ttslen;
const u_char *optr, *pptr, *tptr;
- u_short packet_len;
+ u_short packet_len,pdu_len;
u_int i,j,bit_length,byte_length,metric;
u_char prefix[4]; /* copy buffer for ipv4 prefixes */
#ifdef INET6
@@ -750,8 +750,15 @@
header->fixed_len, (unsigned long)ISIS_IIH_LAN_HEADER_SIZE);
return (0);
}
- printf(", L%s Lan IIH",
- ISIS_MASK_LEVEL_BITS(pdu_type) ? "1" : "2");
+
+ pdu_len=EXTRACT_16BITS(header_iih_lan->pdu_len);
+ if (packet_len>pdu_len)
+ packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
+
+ printf(", L%s Lan IIH (%u)",
+ ISIS_MASK_LEVEL_BITS(pdu_type) ? "1" : "2",
+ pdu_len);
+
TCHECK(*header_iih_lan);
printf("\n\t\t source-id: ");
isis_print_sysid(header_iih_lan->source_id);
@@ -788,7 +795,12 @@
header->fixed_len, (unsigned long)ISIS_IIH_PTP_HEADER_SIZE);
return (0);
}
- printf(", PTP IIH");
+
+ pdu_len=EXTRACT_16BITS(header_iih_ptp->pdu_len);
+ if (packet_len>pdu_len)
+ packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
+
+ printf(", PTP IIH (%u)",pdu_len);
TCHECK(*header_iih_ptp);
printf("\n\t\t source-id: ");
isis_print_sysid(header_iih_ptp->source_id);
@@ -824,10 +836,15 @@
header->fixed_len, (unsigned long)ISIS_LSP_HEADER_SIZE);
return (0);
}
+
+ pdu_len=EXTRACT_16BITS(header_lsp->pdu_len);
+ if (packet_len>pdu_len)
+ packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
+
if (pdu_type == L1_LSP)
- printf(", L1 LSP");
+ printf(", L1 LSP (%u)",pdu_len);
else if (pdu_type == L2_LSP)
- printf(", L2 LSP");
+ printf(", L2 LSP (%u)",pdu_len);
TCHECK(*header_lsp);
printf("\n\t\t lsp-id: ");
@@ -859,7 +876,12 @@
header->fixed_len, (unsigned long)ISIS_CSNP_HEADER_SIZE);
return (0);
}
- printf(", L%s CSNP", ISIS_MASK_LEVEL_BITS(pdu_type) ? "2" : "1");
+
+ pdu_len=EXTRACT_16BITS(header_csnp->pdu_len);
+ if (packet_len>pdu_len)
+ packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
+
+ printf(", L%s CSNP (%u)", ISIS_MASK_LEVEL_BITS(pdu_type) ? "2" : "1", pdu_len);
TCHECK(*header_csnp);
printf("\n\t\t source-id: ");
isis_print_nodeid(header_csnp->source_id);
@@ -879,7 +901,12 @@
header->fixed_len, (unsigned long)ISIS_PSNP_HEADER_SIZE);
return (0);
}
- printf(", L%s PSNP", ISIS_MASK_LEVEL_BITS(pdu_type) ? "2" : "1");
+
+ pdu_len=EXTRACT_16BITS(header_psnp->pdu_len);
+ if (packet_len>pdu_len)
+ packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
+
+ printf(", L%s PSNP (%u)", ISIS_MASK_LEVEL_BITS(pdu_type) ? "2" : "1", pdu_len);
TCHECK(*header_psnp);
printf("\n\t\t source-id: ");
isis_print_nodeid(header_psnp->source_id);
