Add printing support for vsockmon devices.

Print Linux 4.12 vsockmon captures:

  # modprobe vsockmon
  # ip link add type vsockmon
  # ip link set vsockmon0 up
  # tcpdump -i vsockmon0
  16:25:24.987917 VIRTIO 3.1025 > 2.1234 CONNECT, length 76
  16:25:24.987963 VIRTIO 2.1234 > 3.1025 CONNECT, length 76
  16:25:26.568271 VIRTIO 3.1025 > 2.1234 PAYLOAD, length 82
  16:25:26.568512 VIRTIO 2.1234 > 3.1025 CONTROL, length 76
  16:25:28.411335 VIRTIO 3.1025 > 2.1234 DISCONNECT, length 76
  16:25:28.411628 VIRTIO 2.1234 > 3.1025 DISCONNECT, length 76

For more information about vsock see:
http://wiki.qemu.org/Features/VirtioVsock

1 files changed, 257 insertions, 0 deletions

diff --git a/print-vsock.c b/print-vsock.c
new file mode 100644
index 00000000..6d8a44e1
--- /dev/null
+++ b/print-vsock.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright (c) 2016 Gerard Garcia <nouboh@gmail.com>
+ * Copyright (c) 2017 Red Hat, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in
+ *      the documentation and/or other materials provided with the
+ *      distribution.
+ *   3. The names of the authors may not be used to endorse or promote
+ *      products derived from this software without specific prior
+ *      written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+/* \summary: Linux vsock printer */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "netdissect-stdinc.h"
+#include <stddef.h>
+
+#include "netdissect.h"
+#include "extract.h"
+
+enum af_vsockmon_transport {
+	AF_VSOCK_TRANSPORT_UNKNOWN = 0,
+	AF_VSOCK_TRANSPORT_NO_INFO = 1,		/* No transport information */
+	AF_VSOCK_TRANSPORT_VIRTIO = 2,		/* Virtio transport header */
+};
+
+static const struct tok vsock_transport[] = {
+	{AF_VSOCK_TRANSPORT_UNKNOWN, "UNKNOWN"},
+	{AF_VSOCK_TRANSPORT_NO_INFO, "NO_INFO"},
+	{AF_VSOCK_TRANSPORT_VIRTIO, "VIRTIO"},
+	{ 0, NULL }
+};
+
+enum af_vsockmon_op {
+	AF_VSOCK_OP_UNKNOWN = 0,
+	AF_VSOCK_OP_CONNECT = 1,
+	AF_VSOCK_OP_DISCONNECT = 2,
+	AF_VSOCK_OP_CONTROL = 3,
+	AF_VSOCK_OP_PAYLOAD = 4,
+};
+
+static const struct tok vsock_op[] = {
+	{AF_VSOCK_OP_UNKNOWN, "UNKNOWN"},
+	{AF_VSOCK_OP_CONNECT, "CONNECT"},
+	{AF_VSOCK_OP_DISCONNECT, "DISCONNECT"},
+	{AF_VSOCK_OP_CONTROL, "CONTROL"},
+	{AF_VSOCK_OP_PAYLOAD, "PAYLOAD"},
+	{ 0, NULL }
+};
+
+enum virtio_vsock_type {
+	VIRTIO_VSOCK_TYPE_STREAM = 1,
+};
+
+static const struct tok virtio_type[] = {
+	{VIRTIO_VSOCK_TYPE_STREAM, "STREAM"},
+	{ 0, NULL }
+};
+
+enum virtio_vsock_op {
+	VIRTIO_VSOCK_OP_INVALID = 0,
+	VIRTIO_VSOCK_OP_REQUEST = 1,
+	VIRTIO_VSOCK_OP_RESPONSE = 2,
+	VIRTIO_VSOCK_OP_RST = 3,
+	VIRTIO_VSOCK_OP_SHUTDOWN = 4,
+	VIRTIO_VSOCK_OP_RW = 5,
+	VIRTIO_VSOCK_OP_CREDIT_UPDATE = 6,
+	VIRTIO_VSOCK_OP_CREDIT_REQUEST = 7,
+};
+
+static const struct tok virtio_op[] = {
+	{VIRTIO_VSOCK_OP_INVALID, "INVALID"},
+	{VIRTIO_VSOCK_OP_REQUEST, "REQUEST"},
+	{VIRTIO_VSOCK_OP_RESPONSE, "RESPONSE"},
+	{VIRTIO_VSOCK_OP_RST, "RST"},
+	{VIRTIO_VSOCK_OP_SHUTDOWN, "SHUTDOWN"},
+	{VIRTIO_VSOCK_OP_RW, "RW"},
+	{VIRTIO_VSOCK_OP_CREDIT_UPDATE, "CREDIT UPDATE"},
+	{VIRTIO_VSOCK_OP_CREDIT_REQUEST, "CREDIT REQUEST"},
+	{ 0, NULL }
+};
+
+/* All fields are little-endian */
+
+struct virtio_vsock_hdr {
+	nd_uint64_t	src_cid;
+	nd_uint64_t	dst_cid;
+	nd_uint32_t	src_port;
+	nd_uint32_t	dst_port;
+	nd_uint32_t	len;
+	nd_uint16_t	type;		/* enum virtio_vsock_type */
+	nd_uint16_t	op;		/* enum virtio_vsock_op */
+	nd_uint32_t	flags;
+	nd_uint32_t	buf_alloc;
+	nd_uint32_t	fwd_cnt;
+};
+
+struct af_vsockmon_hdr {
+	nd_uint64_t	src_cid;
+	nd_uint64_t	dst_cid;
+	nd_uint32_t	src_port;
+	nd_uint32_t	dst_port;
+	nd_uint16_t	op;		/* enum af_vsockmon_op */
+	nd_uint16_t	transport;	/* enum af_vosckmon_transport */
+	nd_uint16_t	len;		/* size of transport header */
+	nd_uint8_t	reserved[2];
+};
+
+static void
+vsock_virtio_hdr_print(netdissect_options *ndo, const struct virtio_vsock_hdr *hdr)
+{
+	uint16_t u16_v;
+	uint32_t u32_v;
+
+	u32_v = GET_LE_U_4(&hdr->len);
+	ND_PRINT("len %u", u32_v);
+
+	u16_v = GET_LE_U_2(&hdr->type);
+	ND_PRINT(", type %s",
+		 tok2str(virtio_type, "Invalid type (%hu)", u16_v));
+
+	u16_v = GET_LE_U_2(&hdr->op);
+	ND_PRINT(", op %s",
+		 tok2str(virtio_op, "Invalid op (%hu)", u16_v));
+
+	u32_v = GET_LE_U_4(&hdr->flags);
+	ND_PRINT(", flags %x", u32_v);
+
+	u32_v = GET_LE_U_4(&hdr->buf_alloc);
+	ND_PRINT(", buf_alloc %u", u32_v);
+
+	u32_v = GET_LE_U_4(&hdr->fwd_cnt);
+	ND_PRINT(", fwd_cnt %u", u32_v);
+}
+
+static size_t
+vsock_transport_hdr_size(uint16_t transport)
+{
+	switch (transport) {
+		case AF_VSOCK_TRANSPORT_VIRTIO:
+			return sizeof(struct virtio_vsock_hdr);
+		default:
+			return 0;
+	}
+}
+
+/* Returns 0 on success, -1 on truncation */
+static int
+vsock_transport_hdr_print(netdissect_options *ndo, uint16_t transport,
+                          const u_char *p, const u_int len)
+{
+	size_t transport_size = vsock_transport_hdr_size(transport);
+	const void *hdr;
+
+	if (len < sizeof(struct af_vsockmon_hdr) + transport_size) {
+		return -1;
+	}
+
+	hdr = p + sizeof(struct af_vsockmon_hdr);
+	switch (transport) {
+		case AF_VSOCK_TRANSPORT_VIRTIO:
+			ND_PRINT(" (");
+			vsock_virtio_hdr_print(ndo, hdr);
+			ND_PRINT(")");
+			break;
+		default:
+			break;
+	}
+	return 0;
+}
+
+static void
+vsock_hdr_print(netdissect_options *ndo, const u_char *p, const u_int len)
+{
+	const struct af_vsockmon_hdr *hdr = (const struct af_vsockmon_hdr *)p;
+	uint16_t hdr_transport, hdr_op;
+	uint32_t hdr_src_port, hdr_dst_port;
+	uint64_t hdr_src_cid, hdr_dst_cid;
+	size_t total_hdr_size;
+	int ret = 0;
+
+	hdr_transport = GET_LE_U_2(&hdr->transport);
+	ND_PRINT("%s",
+		 tok2str(vsock_transport, "Invalid transport (%u)",
+			  hdr_transport));
+
+	/* If verbose level is more than 0 print transport details */
+	if (ndo->ndo_vflag) {
+		ret = vsock_transport_hdr_print(ndo, hdr_transport, p, len);
+		if (ret == 0)
+			ND_PRINT("\n\t");
+	} else
+		ND_PRINT(" ");
+
+	hdr_src_cid = GET_LE_U_8(&hdr->src_cid);
+	hdr_dst_cid = GET_LE_U_8(&hdr->dst_cid);
+	hdr_src_port = GET_LE_U_4(&hdr->src_port);
+	hdr_dst_port = GET_LE_U_4(&hdr->dst_port);
+	hdr_op = GET_LE_U_2(&hdr->op);
+	ND_PRINT("%" PRIu64 ".%u > %" PRIu64 ".%u %s, length %u",
+		 hdr_src_cid, hdr_src_port,
+		 hdr_dst_cid, hdr_dst_port,
+		 tok2str(vsock_op, " invalid op (%u)", hdr_op),
+		 len);
+
+	if (ret < 0)
+		goto trunc;
+
+	/* If debug level is more than 1 print payload contents */
+	total_hdr_size = sizeof(struct af_vsockmon_hdr) +
+			 vsock_transport_hdr_size(hdr_transport);
+	if (ndo->ndo_vflag > 1 && hdr_op == AF_VSOCK_OP_PAYLOAD) {
+		if (len > total_hdr_size) {
+			const u_char *payload = p + total_hdr_size;
+
+			ND_PRINT("\n");
+			print_unknown_data(ndo, payload, "\t",
+					   len - total_hdr_size);
+		} else
+			goto trunc;
+	}
+	return;
+
+trunc:
+	nd_print_trunc(ndo);
+}
+
+u_int
+vsock_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h,
+	       const u_char *cp)
+{
+	u_int len = h->caplen;
+
+	ndo->ndo_protocol = "vsock";
+
+	if (len < sizeof(struct af_vsockmon_hdr))
+		nd_print_trunc(ndo);
+	else
+		vsock_hdr_print(ndo, cp, len);
+
+	return len;
+}