PPPoE: Modernize packet parsing style.

Enable ND_LONGJMP_FROM_TCHECK, remove a redundant custom bounds check and
a variable, report an undersized header as an invalid packet with the
reason.

diff --git a/print-pppoe.c b/print-pppoe.c
index 50ae0996af72e1df251b65ff37b484063d32a4c5..65518dff16d97adde75b1d7eb537d602354f7998 100644 (file)
--- a/print-pppoe.c
+++ b/print-pppoe.c
@@ -31,6 +31,7 @@
 
 #include "netdissect-ctype.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "extract.h"
 
@@ -97,18 +98,13 @@ u_int
 pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length)
 {
        uint16_t pppoe_ver, pppoe_type, pppoe_code, pppoe_sessionid;
-       u_int pppoe_length, caplen;
+       u_int pppoe_length;
        const u_char *pppoe_packet, *pppoe_payload;
 
        ndo->ndo_protocol = "pppoe";
-       caplen = ndo->ndo_snapend - bp;
-       if (caplen < PPPOE_HDRLEN) {
-               nd_print_trunc(ndo);
-               return caplen;
-       }
        if (length < PPPOE_HDRLEN) {
-               nd_print_trunc(ndo);
-               return length;
+               ND_PRINT(" (length %u < %u)", length, PPPOE_HDRLEN);
+               goto invalid;
        }
        length -= PPPOE_HDRLEN;
        pppoe_packet = bp;
@@ -202,8 +198,9 @@ pppoe_print(netdissect_options *ndo, const u_char *bp, u_int length)
                ND_PRINT(" ");
                return (PPPOE_HDRLEN + ppp_print(ndo, pppoe_payload, pppoe_length));
        }
+       /* NOTREACHED */
 
-trunc:
-       nd_print_trunc(ndo);
-       return PPPOE_HDRLEN;
+invalid:
+       nd_print_invalid(ndo);
+       return 0;
 }