Changeset b39eaee

Timestamp:

01/07/19 10:35:41 (2 years ago)

Author:

Jacob Van Walraven <jcv9@…>

Branches:

develop

Children:

89ed4a0

Parents:

51276bd

git-author:

Jacob Van Walraven <jcv9@…> (12/14/18 11:54:41)

git-committer:

Jacob Van Walraven <jcv9@…> (01/07/19 10:35:41)

Message:

cleanup some code and handle some cases where fields need to be byteswapped

File:

• lib/format_pcapng.c (modified) (10 diffs)

lib/format_pcapng.c

@@ -234 +234 @@
 }
 
-static inline uint32_t pcapng_get_header_type(const libtrace_packet_t *packet) {
-        uint32_t *type = (uint32_t *)packet->buffer;
-
-        /* Section blocks, interface blocks, name resolution blocks, stats blocks and
-         * Custom blocks are all of type trace_type_pcapng_meta */
-        if (packet->type == TRACE_RT_PCAPNG_META) {
-                return *type;
-        }
-
-        if (packet->type == 0x00000006 || packet->type == 0x00000003) {
-                return *type;
-        }
-        /* not a pcapng header type */
-        return 0;
+static inline uint32_t pcapng_swap32(libtrace_packet_t *packet, uint32_t value) {
+        if (DATAOUT(packet->trace)->byteswapped) {
+                return byteswap32(value);
+        } else {
+                return value;
+        }
+}
+static inline uint32_t pcapng_swap16(libtrace_packet_t *packet, uint32_t value) {
+        if (DATAOUT(packet->trace)->byteswapped) {
+                return byteswap16(value);
+        } else {
+                return value;
+        }
 }
 static inline uint32_t pcapng_get_blocklen(const libtrace_packet_t *packet) {
         struct pcapng_peeker *hdr = (struct pcapng_peeker *)packet->buffer;
 
-        if (DATAOUT(packet->trace)->byteswapped) {
+        if (DATA(packet->trace)->byteswapped) {
                 return byteswap32(hdr->blocklen);
         } else {
@@ -578 +577 @@
 
         /* If the packet is already encapsulated in a pcapng frame just output it */
-        switch (pcapng_get_header_type(packet)) {
+        switch (pcapng_get_record_type(packet)) {
                 case PCAPNG_SECTION_TYPE: {
-                        /* If we get a section header we need to calculate the
-                         * the byte ordering */
-                        pcapng_sec_t *sechdr = (pcapng_sec_t *)packet->buffer;
-                        if (sechdr->ordering == 0x1A2B3C4D) {
+                        /* If the section header passed in is byteswapped, everything we output
+                         * till the next section header needs to be byteswapped. The next header
+                         * will determine if we need to continue swapping bytes */
+                        if (DATA(libtrace)->byteswapped) {
+                                DATAOUT(libtrace)->byteswapped = true;
+                        } else {
                                 DATAOUT(libtrace)->byteswapped = false;
-                        } else if (sechdr->ordering == 0x4D3C2B1A) {
-                                DATAOUT(libtrace)->byteswapped = true;
                         }
 
@@ -618 +617 @@
                                 return -1;
                         }
+
                         wandio_wwrite(DATAOUT(libtrace)->file, packet->buffer,
-                                pcapng_get_blocklen(packet));
+                                pcapng_get_blocklen(packet));
 
                         return pcapng_get_blocklen(packet);
@@ -636 +636 @@
                                 return -1;
                         }
+
                         wandio_wwrite(DATAOUT(libtrace)->file, packet->buffer,
-                                pcapng_get_blocklen(packet));
+                                pcapng_get_blocklen(packet));
 
                         return pcapng_get_blocklen(packet);
@@ -648 +649 @@
                                 return -1;
                         }
+
                         wandio_wwrite(DATAOUT(libtrace)->file, packet->buffer,
                                 pcapng_get_blocklen(packet));
@@ -654 +656 @@
                 }
                 case PCAPNG_CUSTOM_TYPE: {
-                        wandio_wwrite(DATAOUT(libtrace)->file, packet->buffer,
-                                pcapng_get_blocklen(packet));
+                        if (DATA(libtrace)->byteswapped == DATAOUT(libtrace)->byteswapped) {
+                                wandio_wwrite(DATAOUT(libtrace)->file, packet->buffer,
+                                        pcapng_get_blocklen(packet));
+                        } else {
+
+                        }
 
                         return pcapng_get_blocklen(packet);
@@ -665 +671 @@
                                 /* Create section block */
                                 pcapng_sec_t sechdr;
-                                sechdr.blocktype = PCAPNG_SECTION_TYPE;
-                                sechdr.blocklen = 28;
-                                sechdr.ordering = 0x1A2B3C4D;
-                                sechdr.majorversion = 1;
+                                sechdr.blocktype = pcapng_swap32(packet, PCAPNG_SECTION_TYPE);
+                                sechdr.blocklen = pcapng_swap32(packet, 28);
+                                sechdr.ordering = pcapng_swap32(packet, 0x1A2B3C4D);
+                                sechdr.majorversion = pcapng_swap16(packet, 1);
                                 sechdr.minorversion = 0;
                                 sechdr.sectionlen = 0xFFFFFFFFFFFFFFFF;
@@ -683 +689 @@
                                 /* Create interface block*/
                                 pcapng_int_t inthdr;
-                                inthdr.blocktype = PCAPNG_INTERFACE_TYPE;
-                                inthdr.blocklen = 20;
-                                inthdr.linktype = libtrace_to_pcap_dlt(linktype);
+                                inthdr.blocktype = pcapng_swap32(packet, PCAPNG_INTERFACE_TYPE);
+                                inthdr.blocklen = pcapng_swap32(packet, 20);
+                                inthdr.linktype = pcapng_swap16(packet, libtrace_to_pcap_dlt(linktype));
                                 inthdr.reserved = 0;
                                 inthdr.snaplen = 0;
@@ -708 +714 @@
         uint32_t blocklen;
         uint32_t padding;
+        uint32_t caplen;
+        uint32_t wirelen;
         void *padding_data;
         pcapng_epkt_t epkthdr;
@@ -713 +721 @@
         link = trace_get_packet_buffer(packet, &linktype, &remaining);
 
-        epkthdr.wlen = trace_get_wire_length(packet);
-        epkthdr.caplen = trace_get_capture_length(packet);
+        wirelen = trace_get_wire_length(packet);
+        caplen = trace_get_capture_length(packet);
 
         /* trace_get_wirelength includes FCS, while pcapng doesn't */
         if (trace_get_link_type(packet)==TRACE_TYPE_ETH) {
-                if (epkthdr.wlen >= 4) {
-                        epkthdr.wlen -= 4;
+                if (wirelen >= 4) {
+                        wirelen -= 4;
                 } else {
-                        epkthdr.wlen = 0;
+                        wirelen = 0;
                 }
         }
         /* capture length should always be less than the wirelength */
-        if (epkthdr.caplen > epkthdr.wlen) {
-                epkthdr.caplen = epkthdr.wlen;
+        if (caplen > wirelen) {
+                caplen = wirelen;
         }
 
         /* calculate padding to 32bits */
-        padding = epkthdr.caplen % 4;
+        padding = caplen % 4;
         if (padding) { padding = 4 - padding; }
         padding_data = calloc(1, padding);
 
+        /* get pcapng_timestamp */
+        struct pcapng_timestamp ts = pcapng_get_timestamp(packet);
+
         /* calculate the block length */
-        blocklen = sizeof(epkthdr) + sizeof(epkthdr.blocklen) + epkthdr.caplen + padding;
-
-        epkthdr.blocktype = PCAPNG_ENHANCED_PACKET_TYPE;
-        epkthdr.blocklen = blocklen;
-        epkthdr.interfaceid = DATAOUT(libtrace)->nextintid-1;
-
-        /* get pcapng_timestamp */
-        struct pcapng_timestamp ts = pcapng_get_timestamp(packet);
-        epkthdr.timestamp_high = ts.timehigh;
-        epkthdr.timestamp_low = ts.timelow;
+        blocklen = sizeof(epkthdr) + sizeof(epkthdr.blocklen) + caplen + padding;
+
+        /* construct the packet */
+        epkthdr.blocktype = pcapng_swap32(packet, PCAPNG_ENHANCED_PACKET_TYPE);
+        epkthdr.blocklen = pcapng_swap32(packet, blocklen);
+        epkthdr.interfaceid = pcapng_swap32(packet, DATAOUT(libtrace)->nextintid-1);
+        epkthdr.timestamp_high = pcapng_swap32(packet, ts.timehigh);
+        epkthdr.timestamp_low = pcapng_swap32(packet, ts.timelow);
+        epkthdr.wlen = pcapng_swap32(packet, wirelen);
+        epkthdr.caplen = pcapng_swap32(packet, caplen);
 
         /* output enhanced packet header */
         wandio_wwrite(DATAOUT(libtrace)->file, &epkthdr, sizeof(epkthdr));
         /* output the packet */
-        wandio_wwrite(DATAOUT(libtrace)->file, link, (size_t)epkthdr.caplen);
+        wandio_wwrite(DATAOUT(libtrace)->file, link, (size_t)caplen);
         /* output padding */
         wandio_wwrite(DATAOUT(libtrace)->file, padding_data, (size_t)padding);