LISP: Modernize packet parsing

Define ND_LONGJMP_FROM_TCHECK and remove a 'trunc' label.
Make a bounds check conditional.
Use ND_ICHECK_U() for a length test.
Fix a bounds check, not invalid, but truncated.
(The bounds check is done by hex_print_with_offset() via hex_print().)
Use ND_TTEST_LEN() instead of testing ndo->ndo_snapend.
Remove an useless variable ('packet_iterator' same as 'bp').

Remove/update some comments.
Fix some indentations.
Remove some extra blank lines.

Update the outputs of two tests accordingly.

diff --git a/print-lisp.c b/print-lisp.c
index b995f2dfb8722cb8bf798b31be46b600a688bd6c..24255564d8dc3f5d16ad80fe9fd998629ffbe965 100644 (file)
--- a/print-lisp.c
+++ b/print-lisp.c
@@ -97,6 +97,8 @@
 #include <config.h>
 
 #include "netdissect-stdinc.h"
+
+#define ND_LONGJMP_FROM_TCHECK
 #include "netdissect.h"
 
 #include "ip.h"
@@ -105,7 +107,6 @@
 #include "extract.h"
 #include "addrtoname.h"
 
-
 #define IPv4_AFI                       1
 #define IPv6_AFI                       2
 #define TYPE_INDEX                     4
@@ -239,28 +240,26 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
        uint16_t packet_offset;
        uint16_t auth_data_len;
        uint32_t ttl;
-       const u_char *packet_iterator;
        const lisp_map_register_hdr *lisp_hdr;
        const lisp_map_register_eid *lisp_eid;
        const lisp_map_register_loc *lisp_loc;
 
        ndo->ndo_protocol = "lisp";
-       /* Check if enough bytes for header are available */
-       ND_TCHECK_LEN(bp, MAP_REGISTER_HDR_LEN);
        lisp_hdr = (const lisp_map_register_hdr *) bp;
        lisp_hdr_flag(ndo, lisp_hdr);
        /* Supporting only MAP NOTIFY and MAP REGISTER LISP packets */
        type_and_flag = GET_U_1(lisp_hdr->type_and_flag);
        type = extract_lisp_type(type_and_flag);
-       if ((type != LISP_MAP_REGISTER) && (type != LISP_MAP_NOTIFY))
+       if ((type != LISP_MAP_REGISTER) && (type != LISP_MAP_NOTIFY)) {
+               ND_TCHECK_LEN(bp, MAP_REGISTER_HDR_LEN);
                return;
+       }
 
        /* Find if the packet contains xTR and Site-ID data */
        xtr_present = is_xtr_data_present(type, type_and_flag);
 
        /* Extract the number of EID records present */
        auth_data_len = GET_BE_U_2(lisp_hdr->auth_data_len);
-       packet_iterator = (const u_char *)(lisp_hdr);
        packet_offset = MAP_REGISTER_HDR_LEN;
        record_count = GET_U_1(lisp_hdr->record_count);
 
@@ -268,25 +267,22 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
                key_id = GET_BE_U_2(lisp_hdr->key_id);
                ND_PRINT("\n    %u record(s), ", record_count);
                ND_PRINT("Authentication %s,",
-                       tok2str(auth_type, "unknown-type", key_id));
-               hex_print(ndo, "\n    Authentication-Data: ", packet_iterator +
-                                               packet_offset, auth_data_len);
+                        tok2str(auth_type, "unknown-type", key_id));
+               hex_print(ndo, "\n    Authentication-Data: ",
+                         bp + packet_offset, auth_data_len);
        } else {
                ND_PRINT(" %u record(s),", record_count);
        }
        packet_offset += auth_data_len;
 
-       if (record_count == 0)
-               goto invalid;
+       ND_ICHECK_U(record_count, ==, 0);
 
        /* Print all the EID records */
        while ((length > packet_offset) && (record_count != 0)) {
                record_count--;
-               ND_TCHECK_LEN(packet_iterator + packet_offset,
-                             MAP_REGISTER_EID_LEN);
+               ND_TCHECK_LEN(bp + packet_offset, MAP_REGISTER_EID_LEN);
                ND_PRINT("\n");
-               lisp_eid = (const lisp_map_register_eid *)
-                               ((const u_char *)lisp_hdr + packet_offset);
+               lisp_eid = (const lisp_map_register_eid *) (bp + packet_offset);
                packet_offset += MAP_REGISTER_EID_LEN;
                mask_len = GET_U_1(lisp_eid->eid_prefix_mask_length);
                eid_afi = GET_BE_U_2(lisp_eid->eid_prefix_afi);
@@ -303,14 +299,14 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
                switch (eid_afi) {
                case IPv4_AFI:
                        ND_PRINT(" EID %s/%u,",
-                               GET_IPADDR_STRING(packet_iterator + packet_offset),
-                               mask_len);
+                                GET_IPADDR_STRING(bp + packet_offset),
+                                mask_len);
                        packet_offset += 4;
                        break;
                case IPv6_AFI:
                        ND_PRINT(" EID %s/%u,",
-                               GET_IP6ADDR_STRING(packet_iterator + packet_offset),
-                               mask_len);
+                                GET_IP6ADDR_STRING(bp + packet_offset),
+                                mask_len);
                        packet_offset += 16;
                        break;
                default:
@@ -324,9 +320,8 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
 
                while (loc_count != 0) {
                        loc_count--;
-                       ND_TCHECK_LEN(packet_iterator + packet_offset,
-                                     MAP_REGISTER_LOC_LEN);
-                       lisp_loc = (const lisp_map_register_loc *) (packet_iterator + packet_offset);
+                       ND_TCHECK_LEN(bp + packet_offset, MAP_REGISTER_LOC_LEN);
+                       lisp_loc = (const lisp_map_register_loc *) (bp + packet_offset);
                        packet_offset += MAP_REGISTER_LOC_LEN;
                        loc_afi = GET_BE_U_2(lisp_loc->locator_afi);
 
@@ -336,14 +331,12 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
                        switch (loc_afi) {
                        case IPv4_AFI:
                                ND_PRINT(" LOC %s",
-                                        GET_IPADDR_STRING(packet_iterator +
-                                        packet_offset));
+                                        GET_IPADDR_STRING(bp + packet_offset));
                                packet_offset += 4;
                                break;
                        case IPv6_AFI:
                                ND_PRINT(" LOC %s",
-                                        GET_IP6ADDR_STRING(packet_iterator +
-                                        packet_offset));
+                                        GET_IP6ADDR_STRING(bp + packet_offset));
                                packet_offset += 16;
                                break;
                        default:
@@ -363,27 +356,23 @@ lisp_print(netdissect_options *ndo, const u_char *bp, u_int length)
        }
 
        /*
-        * Print xTR and Site ID. Handle the fact that the packet could be invalid.
-        * If the xTR_ID_Present bit is not set, and we still have data to display,
-        * show it as hex data.
+        * Print xTR and Site ID.
+        * If the xTR_ID_Present bit is not set, and we still have data to
+        * display, show it as hex data.
         */
        if (xtr_present) {
-               if (!ND_TTEST_LEN(packet_iterator + packet_offset, 24))
-                       goto invalid;
-               hex_print(ndo, "\n    xTR-ID: ", packet_iterator + packet_offset, 16);
+               hex_print(ndo, "\n    xTR-ID: ", bp + packet_offset, 16);
                ND_PRINT("\n    SITE-ID: %" PRIu64,
-                       GET_BE_U_8(packet_iterator + packet_offset + 16));
+                        GET_BE_U_8(bp + packet_offset + 16));
        } else {
-               /* Check if packet isn't over yet */
-               if (packet_iterator + packet_offset < ndo->ndo_snapend) {
-                       hex_print(ndo, "\n    Data: ", packet_iterator + packet_offset,
-                               ND_BYTES_AVAILABLE_AFTER(packet_iterator + packet_offset));
+               /* If there's at least one byte to print */
+               if (ND_TTEST_LEN(bp + packet_offset, 1)) {
+                       hex_print(ndo, "\n    Data: ", bp + packet_offset,
+                                 ND_BYTES_AVAILABLE_AFTER(bp + packet_offset));
                }
        }
        return;
-trunc:
-       nd_print_trunc(ndo);
-       return;
+
 invalid:
        nd_print_invalid(ndo);
 }
@@ -411,12 +400,9 @@ static void lisp_hdr_flag(netdissect_options *ndo, const lisp_map_register_hdr *
 {
        uint8_t type = extract_lisp_type(GET_U_1(lisp_hdr->type_and_flag));
 
-       if (!ndo->ndo_vflag) {
-               ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type));
+       ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type));
+       if (!ndo->ndo_vflag)
                return;
-       } else {
-               ND_PRINT("%s,", tok2str(lisp_type, "unknown-type-%u", type));
-       }
 
        if (type == LISP_MAP_REGISTER) {
                ND_PRINT(" flags [%s],", bittok2str(map_register_hdr_flag,
@@ -447,4 +433,3 @@ static void loc_hdr_flag(netdissect_options *ndo, uint16_t flag)
 {
        ND_PRINT(" flags [%s],", bittok2str(lisp_loc_flag, "none", flag));
 }
-

diff --git a/tests/lisp_eid_notify-v.out b/tests/lisp_eid_notify-v.out
index 155fbb38ae8da153fa54798428f371620c556087..70eac74f288916c59dd21afee10667f193e60d5d 100644 (file)
--- a/tests/lisp_eid_notify-v.out
+++ b/tests/lisp_eid_notify-v.out
@@ -44,7 +44,7 @@
           Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none],
       Record TTL 1440, Authoritative, No-Action, Map Version: 0, EID 10.30.1.80/32, 1 locator(s)
         LOC 20.20.8.239
-          Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none], (invalid)
+          Priority/Weight 1/100, Multicast Priority/Weight 1/100, flags [none], [|lisp]
     4  2015-08-22 11:09:07.451778 IP (tos 0x0, ttl 64, id 1, offset 0, flags [none], proto UDP (17), length 156)
     192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, flags [none],
     2 record(s), Authentication SHA1,

diff --git a/tests/lisp_eid_notify.out b/tests/lisp_eid_notify.out
index 9e953d7139db860ade5f79c64b8b0f43439e168a..e89db25d41f518efbae65dc1e7112b0f28a2b3ca 100644 (file)
--- a/tests/lisp_eid_notify.out
+++ b/tests/lisp_eid_notify.out
@@ -10,7 +10,7 @@
     3  2015-08-22 11:09:06.507423 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 3 record(s),
  EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253
  EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252
- EID 10.30.1.80/32, 1 locator(s) LOC 20.20.8.239 (invalid)
+ EID 10.30.1.80/32, 1 locator(s) LOC 20.20.8.239 [|lisp]
     4  2015-08-22 11:09:07.451778 IP 192.168.0.105.4342 > 127.0.0.1.4342: LISP-Map-Notify, 2 record(s),
  EID 10.30.1.100/32, 1 locator(s) LOC 20.20.8.253
  EID 10.30.1.96/32, 2 locator(s) LOC 20.20.8.251 LOC 20.20.8.252