WB: Modernize packet parsing style.

Enable ND_LONGJMP_FROM_TCHECK. Remove ND_TTEST*() instances that were
excess and convert the rest to ND_TCHECK*() with comments. Do not guard
ndo_snapend directly. Make sure that functions specific to message types
do not return on truncated data and return -1 when they have looked deep
enough to tell an invalid packet. In wb_print() deduplicate some code and
report invalid packets as invalid instead of truncated, also consider an
unknown packet type invalid. Update a test.

diff --git a/print-wb.c b/print-wb.c
index 3e562af45cc1e4d9edef33385484ccafd58166f4..184809cb9412dc6c985a966b60d0623878cdbbf4 100644 (file)
--- a/print-wb.c
+++ b/print-wb.c
@@ -27,6 +27,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"
@@ -203,7 +204,7 @@ wb_id(netdissect_options *ndo,
        u_int nid;
 
        ND_PRINT(" wb-id:");
-       if (len < sizeof(*id) || !ND_TTEST_SIZE(id))
+       if (len < sizeof(*id))
                return (-1);
        len -= sizeof(*id);
 
@@ -214,6 +215,8 @@ wb_id(netdissect_options *ndo,
               GET_BE_U_4(id->pi_mslot),
               GET_IPADDR_STRING(id->pi_mpage.p_sid),
               GET_BE_U_4(id->pi_mpage.p_uid));
+       /* now the rest of the fixed-size part of struct pkt_id */
+       ND_TCHECK_SIZE(id);
 
        nid = GET_BE_U_2(id->pi_ps.nid);
        if (len < sizeof(*io) * nid)
@@ -223,18 +226,15 @@ wb_id(netdissect_options *ndo,
        sitename = (const u_char *)(io + nid);
 
        c = '<';
-       for (i = 0; i < nid && ND_TTEST_SIZE(io); ++io, ++i) {
+       for (i = 0; i < nid; ++io, ++i) {
                ND_PRINT("%c%s:%u",
                    c, GET_IPADDR_STRING(io->id), GET_BE_U_4(io->off));
                c = ',';
        }
-       if (i >= nid) {
-               ND_PRINT("> \"");
-               (void)nd_print(ndo, sitename, sitename + len);
-               ND_PRINT("\"");
-               return (0);
-       }
-       return (-1);
+       ND_PRINT("> \"");
+       (void)nd_print(ndo, sitename, sitename + len);
+       ND_PRINT("\"");
+       return (0);
 }
 
 static int
@@ -242,7 +242,7 @@ wb_rreq(netdissect_options *ndo,
         const struct pkt_rreq *rreq, u_int len)
 {
        ND_PRINT(" wb-rreq:");
-       if (len < sizeof(*rreq) || !ND_TTEST_SIZE(rreq))
+       if (len < sizeof(*rreq))
                return (-1);
 
        ND_PRINT(" please repair %s %s:%u<%u:%u>",
@@ -259,13 +259,15 @@ wb_preq(netdissect_options *ndo,
         const struct pkt_preq *preq, u_int len)
 {
        ND_PRINT(" wb-preq:");
-       if (len < sizeof(*preq) || !ND_TTEST_SIZE(preq))
+       if (len < sizeof(*preq))
                return (-1);
 
        ND_PRINT(" need %u/%s:%u",
               GET_BE_U_4(preq->pp_low),
               GET_IPADDR_STRING(preq->pp_page.p_sid),
               GET_BE_U_4(preq->pp_page.p_uid));
+       /* now the rest of the fixed-size part of struct pkt_req */
+       ND_TCHECK_SIZE(preq);
        return (0);
 }
 
@@ -275,14 +277,13 @@ wb_prep(netdissect_options *ndo,
 {
        u_int n;
        const struct pgstate *ps;
-       const u_char *ep = ndo->ndo_snapend;
 
        ND_PRINT(" wb-prep:");
-       if (len < sizeof(*prep) || !ND_TTEST_SIZE(prep))
+       if (len < sizeof(*prep))
                return (-1);
        n = GET_BE_U_4(prep->pp_n);
        ps = (const struct pgstate *)(prep + 1);
-       while (n != 0 && ND_TTEST_SIZE(ps)) {
+       while (n != 0) {
                const struct id_off *io, *ie;
                char c = '<';
 
@@ -290,8 +291,10 @@ wb_prep(netdissect_options *ndo,
                    GET_BE_U_4(ps->slot),
                    GET_IPADDR_STRING(ps->page.p_sid),
                    GET_BE_U_4(ps->page.p_uid));
+               /* now the rest of the fixed-size part of struct pgstate */
+               ND_TCHECK_SIZE(ps);
                io = (const struct id_off *)(ps + 1);
-               for (ie = io + GET_U_1(ps->nid); io < ie && ND_TTEST_SIZE(io); ++io) {
+               for (ie = io + GET_U_1(ps->nid); io < ie; ++io) {
                        ND_PRINT("%c%s:%u", c, GET_IPADDR_STRING(io->id),
                            GET_BE_U_4(io->off));
                        c = ',';
@@ -300,7 +303,7 @@ wb_prep(netdissect_options *ndo,
                ps = (const struct pgstate *)io;
                n--;
        }
-       return ((const u_char *)ps <= ep? 0 : -1);
+       return 0;
 }
 
 static void
@@ -313,10 +316,6 @@ wb_dops(netdissect_options *ndo, const struct pkt_dop *dop,
        for ( ; ss <= es; ++ss) {
                u_int t;
 
-               if (!ND_TTEST_SIZE(dh)) {
-                       nd_print_trunc(ndo);
-                       break;
-               }
                t = GET_U_1(dh->dh_type);
 
                ND_PRINT(" %s", tok2str(dop_str, "dop-%u!", t));
@@ -342,7 +341,7 @@ wb_rrep(netdissect_options *ndo,
        const struct pkt_dop *dop = &rrep->pr_dop;
 
        ND_PRINT(" wb-rrep:");
-       if (len < sizeof(*rrep) || !ND_TTEST_SIZE(rrep))
+       if (len < sizeof(*rrep))
                return (-1);
        len -= sizeof(*rrep);
 
@@ -365,7 +364,7 @@ wb_drawop(netdissect_options *ndo,
           const struct pkt_dop *dop, u_int len)
 {
        ND_PRINT(" wb-dop:");
-       if (len < sizeof(*dop) || !ND_TTEST_SIZE(dop))
+       if (len < sizeof(*dop))
                return (-1);
        len -= sizeof(*dop);
 
@@ -391,13 +390,13 @@ wb_print(netdissect_options *ndo,
 {
        const struct pkt_hdr *ph;
        uint8_t type;
+       int print_result;
 
        ndo->ndo_protocol = "wb";
        ph = (const struct pkt_hdr *)hdr;
-       if (len < sizeof(*ph) || !ND_TTEST_SIZE(ph)) {
-               nd_print_trunc(ndo);
-               return;
-       }
+       if (len < sizeof(*ph))
+               goto invalid;
+       ND_TCHECK_SIZE(ph);
        len -= sizeof(*ph);
 
        if (GET_U_1(ph->ph_flags))
@@ -410,43 +409,37 @@ wb_print(netdissect_options *ndo,
                return;
 
        case PT_ID:
-               if (wb_id(ndo, (const struct pkt_id *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_id(ndo, (const struct pkt_id *)(ph + 1), len);
                break;
 
        case PT_RREQ:
-               if (wb_rreq(ndo, (const struct pkt_rreq *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_rreq(ndo, (const struct pkt_rreq *)(ph + 1), len);
                break;
 
        case PT_RREP:
-               if (wb_rrep(ndo, (const struct pkt_rrep *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_rrep(ndo, (const struct pkt_rrep *)(ph + 1), len);
                break;
 
        case PT_DRAWOP:
-               if (wb_drawop(ndo, (const struct pkt_dop *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_drawop(ndo, (const struct pkt_dop *)(ph + 1), len);
                break;
 
        case PT_PREQ:
-               if (wb_preq(ndo, (const struct pkt_preq *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_preq(ndo, (const struct pkt_preq *)(ph + 1), len);
                break;
 
        case PT_PREP:
-               if (wb_prep(ndo, (const struct pkt_prep *)(ph + 1), len) >= 0)
-                       return;
-               nd_print_trunc(ndo);
+               print_result = wb_prep(ndo, (const struct pkt_prep *)(ph + 1), len);
                break;
 
        default:
                ND_PRINT(" wb-%u!", type);
-               return;
+               print_result = -1;
        }
+       if (print_result < 0)
+               goto invalid;
+       return;
+
+invalid:
+       nd_print_invalid(ndo);
 }

diff --git a/tests/rsvp_uni-oobr-3.out b/tests/rsvp_uni-oobr-3.out
index e5643135b8a4a40d0f54e90d0f9dfddad7586b27..4f5560d3ed9a8bb1052e94d01b1854a5c9060209 100644 (file)
--- a/tests/rsvp_uni-oobr-3.out
+++ b/tests/rsvp_uni-oobr-3.out
@@ -1,5 +1,5 @@
     1  14:35:06.131862 IP (tos 0x0, ttl 48, id 25615, offset 0, flags [+, DF, rsvd], proto UDP (17), length 61735, bad cksum 8ef1 (->10e1)!)
-    1.2.3.3.1812 > 64.112.0.96.4567:  wb-29!
+    1.2.3.3.1812 > 64.112.0.96.4567:  wb-29! (invalid)
     2  00:00:20.3980395268 IP (tos 0x2,ECT(0), ttl 248, id 0, offset 0, flags [none], proto RSVP (46), length 54312, bad cksum 3701 (->8972)!)
     54.35.0.0 > 47.16.0.0: 
        RSVPv1 Hello Message (20), Flags: [Refresh reduction capable], length: 65527, ttl: 15, checksum: 0x0902