More Sysdig / system event support.

Add REC_TYPE_SYSCALL to wiretap and use it for Sysdig events. Call the
Sysdig event dissector from the frame dissector. Create a "syscall"
protocol for system calls, but add "frame" items to it for now.

Add the ability to write Sysdig events. This lets us merge packet
capture and syscall capture files.

Change-Id: I12774ec69c89d8e329b6130c67f29aade4e3d778
Reviewed-on: https://code.wireshark.org/review/15078
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

6 files changed, 184 insertions, 13 deletions

diff --git a/epan/dissectors/packet-frame.c b/epan/dissectors/packet-frame.c
index 7b4ab0950b..b761e193c7 100644
--- a/epan/dissectors/packet-frame.c
+++ b/epan/dissectors/packet-frame.c
@@ -51,6 +51,8 @@ void proto_reg_handoff_frame(void);
 
 static int proto_frame = -1;
 static int proto_pkt_comment = -1;
+static int proto_syscall = -1;
+
 static int hf_frame_arrival_time = -1;
 static int hf_frame_shift_offset = -1;
 static int hf_frame_arrival_time_epoch = -1;
@@ -98,6 +100,7 @@ static expert_field ei_incomplete = EI_INIT;
 static int frame_tap = -1;
 
 static dissector_handle_t docsis_handle;
+static dissector_handle_t sysdig_handle;
 
 /* Preferences */
 static gboolean show_file_off       = FALSE;
@@ -250,6 +253,10 @@ dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void*
 		pinfo->current_proto = "Report";
 		break;
 
+	case REC_TYPE_SYSCALL:
+		pinfo->current_proto = "System Call";
+		break;
+
 	default:
 		g_assert_not_reached();
 		break;
@@ -283,17 +290,37 @@ dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void*
 		cap_plurality = plurality(cap_len, "", "s");
 		frame_plurality = plurality(frame_len, "", "s");
 
-		ti = proto_tree_add_protocol_format(tree, proto_frame, tvb, 0, tvb_captured_length(tvb),
-		    "Frame %u: %u byte%s on wire",
-		    pinfo->num, frame_len, frame_plurality);
-		if (generate_bits_field)
-			proto_item_append_text(ti, " (%u bits)", frame_len * 8);
-		proto_item_append_text(ti, ", %u byte%s captured",
-		    cap_len, cap_plurality);
-		if (generate_bits_field) {
-			proto_item_append_text(ti, " (%u bits)",
-			    cap_len * 8);
+		switch (pinfo->phdr->rec_type) {
+		case REC_TYPE_PACKET:
+		case REC_TYPE_FT_SPECIFIC_EVENT:
+		case REC_TYPE_FT_SPECIFIC_REPORT:
+			ti = proto_tree_add_protocol_format(tree, proto_frame, tvb, 0, tvb_captured_length(tvb),
+			"Frame %u: %u byte%s on wire",
+			pinfo->num, frame_len, frame_plurality);
+			if (generate_bits_field)
+				proto_item_append_text(ti, " (%u bits)", frame_len * 8);
+			proto_item_append_text(ti, ", %u byte%s captured",
+			cap_len, cap_plurality);
+			if (generate_bits_field) {
+				proto_item_append_text(ti, " (%u bits)",
+				cap_len * 8);
+			}
+			break;
+
+		case REC_TYPE_SYSCALL:
+			/*
+			 * This gives us a top-of-tree "syscall" protocol
+			 * with "frame" fields underneath. Should we create
+			 * corresponding syscall.time, .time_epoch, etc
+			 * fields and use them instead or would frame.*
+			 * be preferred?
+			 */
+			ti = proto_tree_add_protocol_format(tree, proto_syscall, tvb, 0, tvb_captured_length(tvb),
+			"System Call %u: %u byte%s",
+			pinfo->num, frame_len, frame_plurality);
+			break;
 		}
+
 		if (pinfo->phdr->presence_flags & WTAP_HAS_INTERFACE_ID) {
 			proto_item_append_text(ti, " on interface %u",
 			    pinfo->phdr->interface_id);
@@ -501,6 +528,15 @@ dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void*
 					}
 				}
 				break;
+
+			case REC_TYPE_SYSCALL:
+				/* Sysdig is the only type we currently handle. */
+				if (sysdig_handle) {
+					call_dissector_with_data(sysdig_handle,
+					    tvb, pinfo, parent_tree,
+					    (void *)pinfo->pseudo_header);
+				}
+				break;
 			}
 #ifdef _MSC_VER
 		} __except(EXCEPTION_EXECUTE_HANDLER /* handle all exceptions */) {
@@ -867,6 +903,8 @@ proto_register_frame(void)
 
 	proto_frame = proto_register_protocol("Frame", "Frame", "frame");
 	proto_pkt_comment = proto_register_protocol("Packet comments", "Pkt_Comment", "pkt_comment");
+	proto_syscall = proto_register_protocol("System Call", "Syscall", "syscall");
+
 	proto_register_field_array(proto_frame, hf, array_length(hf));
 	proto_register_field_array(proto_frame, &hf_encap, 1);
 	proto_register_subtree_array(ett, array_length(ett));
@@ -914,6 +952,7 @@ void
 proto_reg_handoff_frame(void)
 {
 	docsis_handle = find_dissector_add_dependency("docsis", proto_frame);
+	sysdig_handle = find_dissector_add_dependency("sysdig", proto_frame);
 }
 
 /*
diff --git a/epan/dissectors/packet-sysdig-event.c b/epan/dissectors/packet-sysdig-event.c
index 15536903df..90ea1a2b34 100644
--- a/epan/dissectors/packet-sysdig-event.c
+++ b/epan/dissectors/packet-sysdig-event.c
@@ -2176,6 +2176,8 @@ proto_register_sysdig_event(void)
     /* Required function calls to register the header fields and subtrees */
     proto_register_field_array(proto_sysdig_event, hf, array_length(hf));
     proto_register_subtree_array(ett, array_length(ett));
+
+    register_dissector("sysdig", dissect_sysdig_event, proto_sysdig_event);
 }
 
 #define BLOCK_TYPE_SYSDIG_EVENT 0x00000204
diff --git a/epan/packet.c b/epan/packet.c
index 8deef8fdef..a3b024747b 100644
--- a/epan/packet.c
+++ b/epan/packet.c
@@ -474,6 +474,10 @@ dissect_record(epan_dissect_t *edt, int file_type_subtype,
 		record_type = "Report";
 		break;
 
+	case REC_TYPE_SYSCALL:
+		record_type = "System Call";
+		break;
+
 	default:
 		/*
 		 * XXX - if we add record types that shouldn't be
diff --git a/wiretap/merge.c b/wiretap/merge.c
index c0c26e2852..eced520ac7 100644
--- a/wiretap/merge.c
+++ b/wiretap/merge.c
@@ -699,11 +699,14 @@ map_phdr_interface_id(struct wtap_pkthdr *phdr, const merge_in_file_t *in_file)
 
     if (phdr->presence_flags & WTAP_HAS_INTERFACE_ID) {
         current_interface_id = phdr->interface_id;
+    } else {
+        return TRUE;
     }
 
     if (current_interface_id >= in_file->idb_index_map->len) {
         /* this shouldn't happen, but in a malformed input file it could */
-        merge_debug("merge::map_phdr_interface_id: current_interface_id >= in_file->idb_index_map->len (ERROR?)");
+        merge_debug("merge::map_phdr_interface_id: current_interface_id (%u) >= in_file->idb_index_map->len (%u) (ERROR?)",
+            current_interface_id, in_file->idb_index_map->len);
         return FALSE;
     }
 
diff --git a/wiretap/pcapng.c b/wiretap/pcapng.c
index 4f2d90428e..305a252d46 100644
--- a/wiretap/pcapng.c
+++ b/wiretap/pcapng.c
@@ -146,7 +146,8 @@ typedef struct pcapng_name_resolution_block_s {
 /*
  * Minimum Sysdig size = minimum block size + packed size of sysdig_event_phdr.
  */
-#define MIN_SYSDIG_EVENT_SIZE    ((guint32)(MIN_BLOCK_SIZE)) + ((16 + 64 + 64 + 32 + 16) / 8)
+#define SYSDIG_EVENT_HEADER_SIZE ((16 + 64 + 64 + 32 + 16)/8) /* CPU ID + TS + TID + Event len + Event type */
+#define MIN_SYSDIG_EVENT_SIZE    ((guint32)(MIN_BLOCK_SIZE + SYSDIG_EVENT_HEADER_SIZE))
 
 /* pcapng: common option header file encoding for every option type */
 typedef struct pcapng_option_header_s {
@@ -2144,7 +2145,7 @@ pcapng_read_sysdig_event_block(FILE_T fh, pcapng_block_header_t *bh, pcapng_t *p
     pcapng_debug("pcapng_read_sysdig_event_block: block_total_length %u",
                   bh->block_total_length);
 
-    wblock->packet_header->rec_type = REC_TYPE_FT_SPECIFIC_EVENT;
+    wblock->packet_header->rec_type = REC_TYPE_SYSCALL;
     wblock->packet_header->pseudo_header.sysdig_event.record_type = BLOCK_TYPE_SYSDIG_EVENT;
     wblock->packet_header->presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN /*|WTAP_HAS_INTERFACE_ID */;
     wblock->packet_header->pkt_tsprec = WTAP_TSPREC_NSEC;
@@ -2175,6 +2176,7 @@ pcapng_read_sysdig_event_block(FILE_T fh, pcapng_block_header_t *bh, pcapng_t *p
     block_read -= MIN_SYSDIG_EVENT_SIZE;
     wblock->packet_header->pseudo_header.sysdig_event.byte_order = G_BYTE_ORDER;
 
+    /* XXX Use Gxxx_FROM_LE macros instead? */
     if (pn->byte_swapped) {
         wblock->packet_header->pseudo_header.sysdig_event.byte_order =
                 G_BYTE_ORDER == G_LITTLE_ENDIAN ? G_BIG_ENDIAN : G_LITTLE_ENDIAN;
@@ -2202,6 +2204,8 @@ pcapng_read_sysdig_event_block(FILE_T fh, pcapng_block_header_t *bh, pcapng_t *p
                                 block_read, err, err_info))
         return FALSE;
 
+    /* XXX Read comment? */
+
     return TRUE;
 }
 
@@ -3097,6 +3101,118 @@ pcapng_write_enhanced_packet_block(wtap_dumper *wdh,
     return TRUE;
 }
 
+static gboolean
+pcapng_write_sysdig_event_block(wtap_dumper *wdh,
+                                   const struct wtap_pkthdr *phdr,
+                                   const union wtap_pseudo_header *pseudo_header, const guint8 *pd, int *err)
+{
+    pcapng_block_header_t bh;
+    const guint32 zero_pad = 0;
+    guint32 pad_len;
+    guint32 phdr_len;
+#if 0
+    gboolean have_options = FALSE;
+    struct option option_hdr;
+    guint32 comment_len = 0, comment_pad_len = 0;
+#endif
+    guint32 options_total_length = 0;
+    guint16 cpu_id;
+    guint64 hdr_ts;
+    guint64 ts;
+    guint64 thread_id;
+    guint32 event_len;
+    guint16 event_type;
+
+    /* Don't write anything we're not willing to read. */
+    if (phdr->caplen > WTAP_MAX_PACKET_SIZE) {
+        *err = WTAP_ERR_PACKET_TOO_LARGE;
+        return FALSE;
+    }
+
+    phdr_len = (guint32)pcap_get_phdr_size(phdr->pkt_encap, pseudo_header);
+    if ((phdr_len + phdr->caplen) % 4) {
+        pad_len = 4 - ((phdr_len + phdr->caplen) % 4);
+    } else {
+        pad_len = 0;
+    }
+
+#if 0
+    /* Check if we should write comment option */
+    if (phdr->opt_comment) {
+        have_options = TRUE;
+        comment_len = (guint32)strlen(phdr->opt_comment) & 0xffff;
+        if ((comment_len % 4)) {
+            comment_pad_len = 4 - (comment_len % 4);
+        } else {
+            comment_pad_len = 0;
+        }
+        options_total_length = options_total_length + comment_len + comment_pad_len + 4 /* comment options tag */ ;
+    }
+    if (have_options) {
+        /* End-of options tag */
+        options_total_length += 4;
+    }
+#endif
+
+    /* write sysdig event block header */
+    bh.block_type = BLOCK_TYPE_SYSDIG_EVENT;
+    bh.block_total_length = (guint32)sizeof(bh) + SYSDIG_EVENT_HEADER_SIZE + phdr_len + phdr->caplen + pad_len + options_total_length + 4;
+
+    if (!wtap_dump_file_write(wdh, &bh, sizeof bh, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof bh;
+
+    /* Sysdig is always LE? */
+    cpu_id = GUINT16_TO_LE(pseudo_header->sysdig_event.cpu_id);
+    hdr_ts = (((guint64)phdr->ts.secs) * 1000000000) + phdr->ts.nsecs;
+    ts = GUINT64_TO_LE(hdr_ts);
+    thread_id = GUINT64_TO_LE(pseudo_header->sysdig_event.thread_id);
+    event_len = GUINT32_TO_LE(pseudo_header->sysdig_event.event_len);
+    event_type = GUINT16_TO_LE(pseudo_header->sysdig_event.event_type);
+
+    if (!wtap_dump_file_write(wdh, &cpu_id, sizeof cpu_id, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof cpu_id;
+
+    if (!wtap_dump_file_write(wdh, &ts, sizeof ts, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof ts;
+
+    if (!wtap_dump_file_write(wdh, &thread_id, sizeof thread_id, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof thread_id;
+
+    if (!wtap_dump_file_write(wdh, &event_len, sizeof event_len, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof event_len;
+
+    if (!wtap_dump_file_write(wdh, &event_type, sizeof event_type, err))
+        return FALSE;
+    wdh->bytes_dumped += sizeof event_type;
+
+    /* write event data */
+    if (!wtap_dump_file_write(wdh, pd, phdr->caplen, err))
+        return FALSE;
+    wdh->bytes_dumped += phdr->caplen;
+
+    /* write padding (if any) */
+    if (pad_len != 0) {
+        if (!wtap_dump_file_write(wdh, &zero_pad, pad_len, err))
+            return FALSE;
+        wdh->bytes_dumped += pad_len;
+    }
+
+    /* XXX Write comment? */
+
+    /* write block footer */
+    if (!wtap_dump_file_write(wdh, &bh.block_total_length,
+                              sizeof bh.block_total_length, err))
+        return FALSE;
+
+    return TRUE;
+
+}
+
 /* Arbitrary. */
 #define NRES_REC_MAX_SIZE ((WTAP_MAX_PACKET_SIZE * 4) + 16)
 static gboolean
@@ -3842,6 +3958,12 @@ static gboolean pcapng_dump(wtap_dumper *wdh,
             }
             break;
 
+        case REC_TYPE_SYSCALL:
+            if (!pcapng_write_sysdig_event_block(wdh, phdr, pseudo_header, pd, err)) {
+                return FALSE;
+            }
+            break;
+
         default:
             /* We don't support writing this record type. */
             *err = WTAP_ERR_UNWRITABLE_REC_TYPE;
diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 6d257ea002..acffcb3d0a 100644
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -1203,6 +1203,7 @@ union wtap_pseudo_header {
 #define REC_TYPE_PACKET               0    /**< packet */
 #define REC_TYPE_FT_SPECIFIC_EVENT    1    /**< file-type-specific event */
 #define REC_TYPE_FT_SPECIFIC_REPORT   2    /**< file-type-specific report */
+#define REC_TYPE_SYSCALL              3    /**< system call */
 
 struct wtap_pkthdr {
     guint     rec_type;         /* what type of record is this? */