net: Add support for capturing VLANs (Jan Kiszka)
This patch is derived from Tristan Gingold's patch. It adds a new VLAN
client type that writes all traffic on the VLAN it is attached to into a
pcap file. Such a file can then be analyzed offline with Wireshark or
tcpdump.
Besides rebasing and some minor cleanups, the major differences to the
original version are:
- support for enabling/disabling via the monitor (host_net_add/remove)
- no special ordering of VLAN client list, qemu_send_packet now takes
care of properly ordered packets
- 64k default capturing limit (I hate tcpdump's default)
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7200 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/net.c b/net.c
index c6b196f..7139f4f 100644
--- a/net.c
+++ b/net.c
@@ -118,6 +118,7 @@
#include "qemu-char.h"
#include "audio/audio.h"
#include "qemu_socket.h"
+#include "qemu-log.h"
#if defined(CONFIG_SLIRP)
#include "libslirp.h"
@@ -1558,6 +1559,106 @@
}
+typedef struct DumpState {
+ VLANClientState *pcap_vc;
+ int fd;
+ int pcap_caplen;
+} DumpState;
+
+#define PCAP_MAGIC 0xa1b2c3d4
+
+struct pcap_file_hdr {
+ uint32_t magic;
+ uint16_t version_major;
+ uint16_t version_minor;
+ int32_t thiszone;
+ uint32_t sigfigs;
+ uint32_t snaplen;
+ uint32_t linktype;
+};
+
+struct pcap_sf_pkthdr {
+ struct {
+ int32_t tv_sec;
+ int32_t tv_usec;
+ } ts;
+ uint32_t caplen;
+ uint32_t len;
+};
+
+static void dump_receive(void *opaque, const uint8_t *buf, int size)
+{
+ DumpState *s = opaque;
+ struct pcap_sf_pkthdr hdr;
+ int64_t ts;
+ int caplen;
+
+ /* Early return in case of previous error. */
+ if (s->fd < 0) {
+ return;
+ }
+
+ ts = muldiv64 (qemu_get_clock(vm_clock),1000000, ticks_per_sec);
+ caplen = size > s->pcap_caplen ? s->pcap_caplen : size;
+
+ hdr.ts.tv_sec = ts / 1000000000LL;
+ hdr.ts.tv_usec = ts % 1000000;
+ hdr.caplen = caplen;
+ hdr.len = size;
+ if (write(s->fd, &hdr, sizeof(hdr)) != sizeof(hdr) ||
+ write(s->fd, buf, caplen) != caplen) {
+ qemu_log("-net dump write error - stop dump\n");
+ close(s->fd);
+ s->fd = -1;
+ }
+}
+
+static void net_dump_cleanup(VLANClientState *vc)
+{
+ DumpState *s = vc->opaque;
+
+ close(s->fd);
+ qemu_free(s);
+}
+
+static int net_dump_init(VLANState *vlan, const char *device,
+ const char *name, const char *filename, int len)
+{
+ struct pcap_file_hdr hdr;
+ DumpState *s;
+
+ s = qemu_malloc(sizeof(DumpState));
+
+ s->fd = open(filename, O_CREAT | O_WRONLY, 0644);
+ if (s->fd < 0) {
+ fprintf(stderr, "-net dump: can't open %s\n", filename);
+ return -1;
+ }
+
+ s->pcap_caplen = len;
+
+ hdr.magic = PCAP_MAGIC;
+ hdr.version_major = 2;
+ hdr.version_minor = 4;
+ hdr.thiszone = 0;
+ hdr.sigfigs = 0;
+ hdr.snaplen = s->pcap_caplen;
+ hdr.linktype = 1;
+
+ if (write(s->fd, &hdr, sizeof(hdr)) < sizeof(hdr)) {
+ perror("-net dump write error");
+ close(s->fd);
+ qemu_free(s);
+ return -1;
+ }
+
+ s->pcap_vc = qemu_new_vlan_client(vlan, device, name, dump_receive, NULL,
+ net_dump_cleanup, s);
+ snprintf(s->pcap_vc->info_str, sizeof(s->pcap_vc->info_str),
+ "dump to %s (len=%d)", filename, len);
+ return 0;
+}
+
/* find or alloc a new VLAN */
VLANState *qemu_find_vlan(int id)
{
@@ -1883,7 +1984,17 @@
ret = net_vde_init(vlan, device, name, vde_sock, vde_port, vde_group, vde_mode);
} else
#endif
- {
+ if (!strcmp(device, "dump")) {
+ int len = 65536;
+
+ if (get_param_value(buf, sizeof(buf), "len", p) > 0) {
+ len = strtol(buf, NULL, 0);
+ }
+ if (!get_param_value(buf, sizeof(buf), "file", p)) {
+ snprintf(buf, sizeof(buf), "qemu-vlan%d.pcap", vlan_id);
+ }
+ ret = net_dump_init(vlan, device, name, buf, len);
+ } else {
fprintf(stderr, "Unknown network device: %s\n", device);
ret = -1;
goto out;
@@ -1908,7 +2019,7 @@
static int net_host_check_device(const char *device)
{
int i;
- const char *valid_param_list[] = { "tap", "socket"
+ const char *valid_param_list[] = { "tap", "socket", "dump"
#ifdef CONFIG_SLIRP
,"user"
#endif
