DCCP: Modernize packet parsing

Enable ND_LONGJMP_FROM_TCHECK.
Use ND_ICHECK*() for length checks.
Fix some length checks.
Add and use standard "invalid" sections.
Remove the redundant ND_TCHECK*() instances.
Add a ND_TCHECK_1().
Factorize some codes.
Update default format for tok2str() calls.
Indicate better invalid packet types, invalid option types,
invalid reset codes and invalid features.
Fix process for DCCP_OPTION_CHANGE_L/DCCP_OPTION_CHANGE_R, not the
same that DCCP_OPTION_CONFIRM_L/DCCP_OPTION_CONFIRM_R process.
Remove spaces in some dccp_feature_num_str[] strings.
Update the output of a test accordingly.

diff --git a/print-dccp.c b/print-dccp.c
index d4131afbf3faf059287eda81d5e1c989b3be2f4b..5a0890a9a481923ca5b423ac1665593be9cc66eb 100644 (file)
--- a/print-dccp.c
+++ b/print-dccp.c
@@ -17,6 +17,7 @@
 
 #include "netdissect-stdinc.h"
 
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 #include "addrtoname.h"
 #include "extract.h"
@@ -182,8 +183,8 @@ static const struct tok dccp_feature_num_str[] = {
        { 5, "ack_ratio" },
        { 6, "send_ack_vector" },
        { 7, "send_ndp_count" },
-       { 8, "minimum checksum coverage" },
-       { 9, "check data checksum" },
+       { 8, "minimum_checksum_coverage" },
+       { 9, "check_data_checksum" },
        { 0, NULL }
 };
 
@@ -280,23 +281,12 @@ dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
        else
                ip6 = NULL;
 
-       /* make sure we have enough data to look at the X bit */
        cp = (const u_char *)(dh + 1);
-       if (cp > ndo->ndo_snapend)
-               goto trunc;
-       if (length < sizeof(struct dccp_hdr)) {
-               ND_PRINT("truncated-dccp - %zu bytes missing!",
-                        sizeof(struct dccp_hdr) - length);
-               return;
-       }
+       ND_ICHECK_ZU(length, <, sizeof(struct dccp_hdr));
 
        /* get the length of the generic header */
        fixed_hdrlen = dccp_basic_hdr_len(ndo, dh);
-       if (length < fixed_hdrlen) {
-               ND_PRINT("truncated-dccp - %u bytes missing!",
-                         fixed_hdrlen - length);
-               return;
-       }
+       ND_ICHECK_U(length, <, fixed_hdrlen);
        ND_TCHECK_LEN(dh, fixed_hdrlen);
 
        sport = GET_BE_U_2(dh->dccph_sport);
@@ -316,18 +306,14 @@ dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
        nd_print_protocol_caps(ndo);
 
        if (ndo->ndo_qflag) {
+               ND_ICHECK_U(length, <, hlen);
                ND_PRINT(" %u", length - hlen);
-               if (hlen > length) {
-                       ND_PRINT(" [bad hdr length %u - too long, > %u]",
-                                 hlen, length);
-               }
                return;
        }
 
        /* other variables in generic header */
        if (ndo->ndo_vflag) {
                ND_PRINT(" (CCVal %u, CsCov %u", DCCPH_CCVAL(dh), DCCPH_CSCOV(dh));
-
                /* checksum calculation */
                if (ND_TTEST_LEN(bp, length)) {
                        uint16_t sum = 0, dccp_sum;
@@ -345,125 +331,67 @@ dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
                }
                ND_PRINT(")");
        }
-       ND_PRINT(" ");
 
        dccph_type = DCCPH_TYPE(dh);
+       ND_PRINT(" %s ", tok2str(dccp_pkt_type_str, "packet-type-%u",
+                dccph_type));
        switch (dccph_type) {
        case DCCP_PKT_REQUEST: {
                const struct dccp_hdr_request *dhr =
                        (const struct dccp_hdr_request *)(bp + fixed_hdrlen);
                fixed_hdrlen += 4;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_TCHECK_SIZE(dhr);
-               ND_PRINT("%s (service=%u) ",
-                         tok2str(dccp_pkt_type_str, "", dccph_type),
-                         GET_BE_U_4(dhr->dccph_req_service));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
+               ND_PRINT("(service=%u) ", GET_BE_U_4(dhr->dccph_req_service));
                break;
        }
        case DCCP_PKT_RESPONSE: {
                const struct dccp_hdr_response *dhr =
                        (const struct dccp_hdr_response *)(bp + fixed_hdrlen);
                fixed_hdrlen += 12;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_TCHECK_SIZE(dhr);
-               ND_PRINT("%s (service=%u) ",
-                         tok2str(dccp_pkt_type_str, "", dccph_type),
-                         GET_BE_U_4(dhr->dccph_resp_service));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
+               ND_PRINT("(service=%u) ", GET_BE_U_4(dhr->dccph_resp_service));
                break;
        }
        case DCCP_PKT_DATA:
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
                break;
        case DCCP_PKT_ACK: {
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        }
        case DCCP_PKT_DATAACK: {
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        }
        case DCCP_PKT_CLOSEREQ:
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_CLOSE:
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_RESET: {
                const struct dccp_hdr_reset *dhr =
                        (const struct dccp_hdr_reset *)(bp + fixed_hdrlen);
                fixed_hdrlen += 12;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                ND_TCHECK_SIZE(dhr);
-               ND_PRINT("%s (code=%s) ",
-                         tok2str(dccp_pkt_type_str, "", dccph_type),
-                         tok2str(dccp_reset_code_str, "invalid", GET_U_1(dhr->dccph_reset_code)));
+               ND_PRINT("(code=%s) ", tok2str(dccp_reset_code_str,
+                        "reset-code-%u (invalid)", GET_U_1(dhr->dccph_reset_code)));
                break;
        }
        case DCCP_PKT_SYNC:
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        case DCCP_PKT_SYNCACK:
                fixed_hdrlen += 8;
-               if (length < fixed_hdrlen) {
-                       ND_PRINT("truncated-%s - %u bytes missing!",
-                                 tok2str(dccp_pkt_type_str, "", dccph_type),
-                                 fixed_hdrlen - length);
-                       return;
-               }
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "", dccph_type));
+               ND_ICHECK_U(length, <, fixed_hdrlen);
                break;
        default:
-               ND_PRINT("%s ", tok2str(dccp_pkt_type_str, "unknown-type-%u", dccph_type));
+               goto invalid;
                break;
        }
 
@@ -486,7 +414,7 @@ dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
                while(1){
                        optlen = dccp_print_option(ndo, cp, hlen);
                        if (!optlen)
-                               break;
+                               goto invalid;
                        if (hlen <= optlen)
                                break;
                        hlen -= optlen;
@@ -496,8 +424,8 @@ dccp_print(netdissect_options *ndo, const u_char *bp, const u_char *data2,
                ND_PRINT(">");
        }
        return;
-trunc:
-       nd_print_trunc(ndo);
+invalid:
+       nd_print_invalid(ndo);
 }
 
 enum dccp_option_type {
@@ -545,35 +473,20 @@ dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)
        uint8_t option, optlen, i;
 
        option = GET_U_1(bp);
+       if (option >= 128)
+               ND_PRINT("CCID option %u", option);
+       else
+               ND_PRINT("%s",
+                        tok2str(dccp_option_values, "option-type-%u", option));
        if (option >= 32) {
                optlen = GET_U_1(bp + 1);
-               if (optlen < 2) {
-                       if (option >= 128)
-                               ND_PRINT("CCID option %u optlen too short",
-                                        option);
-                       else
-                               ND_PRINT("%s optlen too short",
-                                         tok2str(dccp_option_values,
-                                                 "Option %u", option));
-                       return 0;
-               }
+               ND_ICHECK_U(optlen, <, 2);
        } else
                optlen = 1;
 
-       if (hlen < optlen) {
-               if (option >= 128)
-                       ND_PRINT("CCID option %u optlen goes past header length",
-                                 option);
-               else
-                       ND_PRINT("%s optlen goes past header length",
-                                 tok2str(dccp_option_values, "Option %u",
-                                         option));
-               return 0;
-       }
-       ND_TCHECK_LEN(bp, optlen);
+       ND_ICHECKMSG_U("remaining length", hlen, <, optlen);
 
        if (option >= 128) {
-               ND_PRINT("CCID option %u", option);
                switch (optlen) {
                        case 4:
                                ND_PRINT(" %u", GET_BE_U_2(bp + 2));
@@ -582,60 +495,58 @@ dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)
                                ND_PRINT(" %u", GET_BE_U_4(bp + 2));
                                break;
                        default:
+                               ND_PRINT(" 0x");
+                               for (i = 0; i < optlen - 2; i++)
+                                       ND_PRINT("%02x", GET_U_1(bp + 2 + i));
                                break;
                }
        } else {
-               ND_PRINT("%s",
-                        tok2str(dccp_option_values, "Option %u", option));
                switch (option) {
+               case DCCP_OPTION_PADDING:
+               case DCCP_OPTION_MANDATORY:
+               case DCCP_OPTION_SLOW_RECEIVER:
+                       ND_TCHECK_1(bp);
+                       break;
                case DCCP_OPTION_CHANGE_L:
-               case DCCP_OPTION_CONFIRM_L:
                case DCCP_OPTION_CHANGE_R:
+                       ND_ICHECK_U(optlen, <, 4);
+                       ND_PRINT(" %s", tok2str(dccp_feature_num_str,
+                                               "feature-number-%u (invalid)", GET_U_1(bp + 2)));
+                       for (i = 0; i < optlen - 3; i++)
+                               ND_PRINT(" %u", GET_U_1(bp + 3 + i));
+                       break;
+               case DCCP_OPTION_CONFIRM_L:
                case DCCP_OPTION_CONFIRM_R:
-                       if (optlen < 3) {
-                               ND_PRINT(" optlen too short");
-                               return optlen;
-                       }
+                       ND_ICHECK_U(optlen, <, 3);
                        ND_PRINT(" %s", tok2str(dccp_feature_num_str,
-                                               "invalid (%u)", GET_U_1(bp + 2)));
+                                               "feature-number-%u (invalid)", GET_U_1(bp + 2)));
                        for (i = 0; i < optlen - 3; i++)
                                ND_PRINT(" %u", GET_U_1(bp + 3 + i));
                        break;
                case DCCP_OPTION_INIT_COOKIE:
-                       if (optlen > 2) {
-                               ND_PRINT(" 0x");
-                               for (i = 0; i < optlen - 2; i++)
-                                       ND_PRINT("%02x",
-                                                GET_U_1(bp + 2 + i));
-                       }
+                       ND_ICHECK_U(optlen, <, 3);
+                       ND_PRINT(" 0x");
+                       for (i = 0; i < optlen - 2; i++)
+                               ND_PRINT("%02x", GET_U_1(bp + 2 + i));
                        break;
                case DCCP_OPTION_NDP_COUNT:
+                       ND_ICHECK_U(optlen, <, 3);
+                       ND_ICHECK_U(optlen, >, 8);
                        for (i = 0; i < optlen - 2; i++)
                                ND_PRINT(" %u", GET_U_1(bp + 2 + i));
                        break;
                case DCCP_OPTION_ACK_VECTOR_NONCE_0:
-                       if (optlen > 2) {
-                               ND_PRINT(" 0x");
-                               for (i = 0; i < optlen - 2; i++)
-                                       ND_PRINT("%02x",
-                                                GET_U_1(bp + 2 + i));
-                       }
-                       break;
                case DCCP_OPTION_ACK_VECTOR_NONCE_1:
-                       if (optlen > 2) {
-                               ND_PRINT(" 0x");
-                               for (i = 0; i < optlen - 2; i++)
-                                       ND_PRINT("%02x",
-                                                GET_U_1(bp + 2 + i));
-                       }
+                       ND_ICHECK_U(optlen, <, 3);
+                       ND_PRINT(" 0x");
+                       for (i = 0; i < optlen - 2; i++)
+                               ND_PRINT("%02x", GET_U_1(bp + 2 + i));
                        break;
                case DCCP_OPTION_DATA_DROPPED:
-                       if (optlen > 2) {
-                               ND_PRINT(" 0x");
-                               for (i = 0; i < optlen - 2; i++)
-                                       ND_PRINT("%02x",
-                                                GET_U_1(bp + 2 + i));
-                       }
+                       ND_ICHECK_U(optlen, <, 3);
+                       ND_PRINT(" 0x");
+                       for (i = 0; i < optlen - 2; i++)
+                               ND_PRINT("%02x", GET_U_1(bp + 2 + i));
                        break;
                case DCCP_OPTION_TIMESTAMP:
                /*
@@ -646,10 +557,8 @@ dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)
                 *  +--------+--------+--------+--------+--------+--------+
                 *   Type=41  Length=6
                 */
-                       if (optlen == 6)
-                               ND_PRINT(" %u", GET_BE_U_4(bp + 2));
-                       else
-                               ND_PRINT(" [optlen != 6]");
+                       ND_ICHECK_U(optlen, !=, 6);
+                       ND_PRINT(" %u", GET_BE_U_4(bp + 2));
                        break;
                case DCCP_OPTION_TIMESTAMP_ECHO:
                /*
@@ -686,30 +595,35 @@ dccp_print_option(netdissect_options *ndo, const u_char *bp, u_int hlen)
                                break;
                        default:
                                ND_PRINT(" [optlen != 6 or 8 or 10]");
+                               goto invalid;
                                break;
                        }
                        break;
                case DCCP_OPTION_ELAPSED_TIME:
-                       if (optlen == 6)
-                               ND_PRINT(" %u", GET_BE_U_4(bp + 2));
-                       else if (optlen == 4)
+                       switch (optlen) {
+                       case 4:
                                ND_PRINT(" %u", GET_BE_U_2(bp + 2));
-                       else
+                               break;
+                       case 6:
+                               ND_PRINT(" %u", GET_BE_U_4(bp + 2));
+                               break;
+                       default:
                                ND_PRINT(" [optlen != 4 or 6]");
+                               goto invalid;
+                       }
                        break;
                case DCCP_OPTION_DATA_CHECKSUM:
-                       if (optlen > 2) {
-                               ND_PRINT(" ");
-                               for (i = 0; i < optlen - 2; i++)
-                                       ND_PRINT("%02x",
-                                                GET_U_1(bp + 2 + i));
-                       }
+                       ND_ICHECK_U(optlen, !=, 6);
+                       ND_PRINT(" 0x");
+                       for (i = 0; i < optlen - 2; i++)
+                               ND_PRINT("%02x", GET_U_1(bp + 2 + i));
                        break;
+               default:
+                       goto invalid;
                }
        }
 
        return optlen;
-trunc:
-       nd_print_trunc(ndo);
+invalid:
        return 0;
 }

diff --git a/tests/dccp_options-oobr.out b/tests/dccp_options-oobr.out
index f714b35d821a8257318cf8f007a542b73da53506..3ee6118b2ef6be99a6bf00341e652fbb37d3b81c 100644 (file)
--- a/tests/dccp_options-oobr.out
+++ b/tests/dccp_options-oobr.out
@@ -1,9 +1,9 @@
     1  16:59:25.816632 IP (tos 0x0, ttl 64, id 65312, offset 0, flags [DF], proto DCCP (33), length 52)
     139.133.209.176.39420 > 139.133.209.65.5001: DCCP (CCVal 0, CsCov 0, cksum 0xaaf3 (incorrect -> 0x8bf3)) DCCP-Request (service=4105078398) seq 8 <nop, nop, nop, nop, change_l ack_ratio 2, change_r ccid 2, change_l ccid 2>
     2  14:27:00.817006 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto DCCP (33), length 68)
-    139.133.209.65.5001 > 139.133.209.176.39420: DCCP (CCVal 0, CsCov 0) DCCP-Response (service=0) (ack=38464816766) seq 1960341146 <nop, nop, change_l ack_ratio 2,  [|dccp]>
+    139.133.209.65.5001 > 139.133.209.176.39420: DCCP (CCVal 0, CsCov 0) DCCP-Response (service=0) (ack=38464816766) seq 1960341146 <nop, nop, change_l ack_ratio 2, confirm_r [|dccp]
     3  14:27:00.817125 IP (tos 0x0, ttl 64, id 65313, offset 0, flags [DF], proto DCCP (33), length 56)
-    139.133.209.176.39420 > 139.133.209.65.5001: DCCP (CCVal 0, CsCov 0, cksum 0xf53a (incorrect -> 0xf551)) DCCP-Ack (ack=1960341146) seq 38464816767 <nop, confirm_r ack_ratio 2, ack_vector0 0xe9, timestamp_echo [optlen != 6 or 8 or 10]>
+    139.133.209.176.39420 > 139.133.209.65.5001: DCCP (CCVal 0, CsCov 0, cksum 0xf53a (incorrect -> 0xf551)) DCCP-Ack (ack=1960341146) seq 38464816767 <nop, confirm_r ack_ratio 2, ack_vector0 0xe9, timestamp_echo [optlen != 6 or 8 or 10] (invalid)
     4  14:27:00.829614 IP (tos 0x0, ttl 64, id 65314, offset 0, flags [DF], proto DCCP (33), length 152)
     139.133.209.176.46076 > 139.133.209.65.48009: DCCP (CCVal 0, CsCov 6) DCCP-DataAck (ack=1960341146) seq 38464816768 <nop, nop, ack_vector0 0x00, elapsed_time 1249, ndp_count 1>
     5  14:27:00.830145 IP (tos 0x0, ttl 64, id 3176, offset 0, flags [DF], proto DCCP (33), length 52)