RIP: Modernize packet parsing style.

[tcpdump] / print-rip.c

diff --git a/print-rip.c b/print-rip.c
index 0a2bef3e6874537e4cec17c57b9671c4d8d6da94..e9262e10c0f68a10835978725502624e992dca66 100644 (file)
--- a/print-rip.c
+++ b/print-rip.c
@@ -29,6 +29,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"
@@ -195,7 +196,7 @@ rip_entry_print_v1(netdissect_options *ndo, const u_char *p,
 
        /* RFC 1058 */
        if (remaining < RIP_ROUTELEN)
-               return (0);
+               goto invalid;
        ND_TCHECK_SIZE(ni);
        family = GET_BE_U_2(ni->rip_family);
        if (family != BSD_AFNUM_INET && family != 0) {
@@ -220,7 +221,7 @@ rip_entry_print_v1(netdissect_options *ndo, const u_char *p,
                 GET_IPADDR_STRING(ni->rip_dest),
                 GET_BE_U_4(ni->rip_metric));
        return (RIP_ROUTELEN);
-trunc:
+invalid:
        return 0;
 }
 
@@ -233,7 +234,7 @@ rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
        const struct rip_netinfo_v2 *ni;
 
        if (remaining < sizeof(*eh))
-               return (0);
+               goto invalid;
        ND_TCHECK_SIZE(eh);
        family = GET_BE_U_2(eh->rip_family);
        if (family == 0xFFFF) { /* variable-sized authentication structures */
@@ -248,9 +249,8 @@ rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
                        const struct rip_auth_crypto_v2 *ch;
 
                        ch = (const struct rip_auth_crypto_v2 *)p;
-                       ND_TCHECK_SIZE(ch);
                        if (remaining < sizeof(*ch))
-                               return (0);
+                               goto invalid;
                        ND_PRINT("\n\t  Auth header:");
                        ND_PRINT(" Packet Len %u,",
                                 GET_BE_U_2(ch->rip_packet_len));
@@ -275,9 +275,8 @@ rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
                print_unknown_data(ndo, p + sizeof(*eh), "\n\t  ", RIP_ROUTELEN - sizeof(*eh));
        } else { /* BSD_AFNUM_INET or AFI 0 */
                ni = (const struct rip_netinfo_v2 *)p;
-               ND_TCHECK_SIZE(ni);
                if (remaining < sizeof(*ni))
-                       return (0);
+                       goto invalid;
                ND_PRINT("\n\t  AFI %s, %15s/%-2d, tag 0x%04x, metric: %u, next-hop: ",
                         tok2str(bsd_af_values, "%u", family),
                         GET_IPADDR_STRING(ni->rip_dest),
@@ -290,37 +289,26 @@ rip_entry_print_v2(netdissect_options *ndo, const u_char *p,
                        ND_PRINT("self");
        }
        return (RIP_ROUTELEN);
-trunc:
+invalid:
        return 0;
 }
 
 void
 rip_print(netdissect_options *ndo,
-         const u_char *dat, u_int length)
+         const u_char *p, u_int len)
 {
        const struct rip *rp;
        uint8_t vers, cmd;
-       const u_char *p;
-       u_int len, routecount;
        unsigned entry_size;
 
        ndo->ndo_protocol = "rip";
-       if (ndo->ndo_snapend < dat) {
-               nd_print_trunc(ndo);
-               return;
-       }
-       len = ND_BYTES_AVAILABLE_AFTER(dat);
-       if (len > length)
-               len = length;
        if (len < sizeof(*rp)) {
-               nd_print_trunc(ndo);
-               return;
+               ND_PRINT(" (packet length %u)", len);
+               goto invalid;
        }
-       len -= sizeof(*rp);
 
-       rp = (const struct rip *)dat;
+       rp = (const struct rip *)p;
 
-       ND_TCHECK_SIZE(rp);
        vers = GET_U_1(rp->rip_vers);
        ND_PRINT("%sRIPv%u",
                 (ndo->ndo_vflag >= 1) ? "\n\t" : "",
@@ -330,10 +318,13 @@ rip_print(netdissect_options *ndo,
        cmd = GET_U_1(rp->rip_cmd);
        ND_PRINT(", %s, length: %u",
                tok2str(rip_cmd_values, "unknown command (%u)", cmd),
-               length);
+               len);
 
+       ND_TCHECK_SIZE(rp);
        if (ndo->ndo_vflag < 1)
                return;
+       p += sizeof(*rp);
+       len -= sizeof(*rp);
 
        switch (cmd) {
 
@@ -342,21 +333,17 @@ rip_print(netdissect_options *ndo,
                switch (vers) {
 
                case 1:
-                       routecount = length / RIP_ROUTELEN;
-                       ND_PRINT(", routes: %u", routecount);
-                       p = (const u_char *)(rp + 1);
+                       ND_PRINT(", routes: %u", len / RIP_ROUTELEN);
                        while (len != 0) {
                                entry_size = rip_entry_print_v1(ndo, p, len);
                                if (entry_size == 0) {
                                        /* Error */
-                                       nd_print_trunc(ndo);
-                                       break;
+                                       goto invalid;
                                }
                                if (len < entry_size) {
                                        ND_PRINT(" [remaining entries length %u < %u]",
                                                 len, entry_size);
-                                       nd_print_invalid(ndo);
-                                       break;
+                                       goto invalid;
                                }
                                p += entry_size;
                                len -= entry_size;
@@ -364,21 +351,17 @@ rip_print(netdissect_options *ndo,
                        break;
 
                case 2:
-                       routecount = length / RIP_ROUTELEN;
-                       ND_PRINT(", routes: %u or less", routecount);
-                       p = (const u_char *)(rp + 1);
+                       ND_PRINT(", routes: %u or less", len / RIP_ROUTELEN);
                        while (len != 0) {
                                entry_size = rip_entry_print_v2(ndo, p, len);
                                if (entry_size == 0) {
                                        /* Error */
-                                       nd_print_trunc(ndo);
-                                       break;
+                                       goto invalid;
                                }
                                if (len < entry_size) {
                                        ND_PRINT(" [remaining entries length %u < %u]",
                                                 len, entry_size);
-                                       nd_print_invalid(ndo);
-                                       break;
+                                       goto invalid;
                                }
                                p += entry_size;
                                len -= entry_size;
@@ -403,16 +386,18 @@ rip_print(netdissect_options *ndo,
 
        default:
                if (ndo->ndo_vflag <= 1) {
-                       if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
+                       if (!print_unknown_data(ndo, p, "\n\t", len))
                                return;
                }
                break;
        }
        /* do we want to see an additionally hexdump ? */
        if (ndo->ndo_vflag> 1) {
-               if (!print_unknown_data(ndo, (const uint8_t *)rp, "\n\t", length))
+               if (!print_unknown_data(ndo, p, "\n\t", len))
                        return;
        }
-trunc:
        return;
+invalid:
+       nd_print_invalid(ndo);
+       ND_TCHECK_LEN(p, len);
 }