Network traffic dumping via netfilter

index 02c8064..f8afb83 100644
@@ -25,6 +25,7 @@
 #include "clients.h"
 #include "qemu-common.h"
 #include "qemu/error-report.h"
+#include "qemu/iov.h"
 #include "qemu/log.h"
 #include "qemu/timer.h"
 #include "hub.h"

@@ -57,12 +58,15 @@ struct pcap_sf_pkthdr {
     uint32_t len;
 };
 
-static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
+static ssize_t dump_receive_iov(NetClientState *nc, const struct iovec *iov,
+                                int cnt)
 {
     DumpState *s = DO_UPCAST(DumpState, nc, nc);
     struct pcap_sf_pkthdr hdr;
     int64_t ts;
     int caplen;
+    size_t size = iov_size(iov, cnt);
+    struct iovec dumpiov[cnt + 1];
 
     /* Early return in case of previous error. */
     if (s->fd < 0) {

@@ -76,8 +80,12 @@ static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
     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) {
+
+    dumpiov[0].iov_base = &hdr;
+    dumpiov[0].iov_len = sizeof(hdr);
+    cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, 0, caplen);
+
+    if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
         qemu_log("-net dump write error - stop dump\n");
         close(s->fd);
         s->fd = -1;

@@ -86,6 +94,15 @@ static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
     return size;
 }
 
+static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
+{
+    struct iovec iov = {
+        .iov_base = (void *)buf,
+        .iov_len = size
+    };
+    return dump_receive_iov(nc, &iov, 1);
+}
+
 static void dump_cleanup(NetClientState *nc)
 {
     DumpState *s = DO_UPCAST(DumpState, nc, nc);

@@ -97,6 +114,7 @@ static NetClientInfo net_dump_info = {
     .type = NET_CLIENT_OPTIONS_KIND_DUMP,
     .size = sizeof(DumpState),
     .receive = dump_receive,
+    .receive_iov = dump_receive_iov,
     .cleanup = dump_cleanup,
 };
 

index f8afb83..27083d4 100644
@@ -118,13 +118,10 @@ static NetClientInfo net_dump_info = {
     .cleanup = dump_cleanup,
 };
 
-static int net_dump_init(NetClientState *peer, const char *device,
-                         const char *name, const char *filename, int len,
-                         Error **errp)
+static int net_dump_state_init(DumpState *s, const char *filename,
+                               int len, Error **errp)
 {
     struct pcap_file_hdr hdr;
-    NetClientState *nc;
-    DumpState *s;
     struct tm tm;
     int fd;
 

@@ -148,13 +145,6 @@ static int net_dump_init(NetClientState *peer, const char *device,
         return -1;
     }
 
-    nc = qemu_new_net_client(&net_dump_info, peer, device, name);
-
-    snprintf(nc->info_str, sizeof(nc->info_str),
-             "dump to %s (len=%d)", filename, len);
-
-    s = DO_UPCAST(DumpState, nc, nc);
-
     s->fd = fd;
     s->pcap_caplen = len;
 

@@ -167,10 +157,11 @@ static int net_dump_init(NetClientState *peer, const char *device,
 int net_init_dump(const NetClientOptions *opts, const char *name,
                   NetClientState *peer, Error **errp)
 {
-    int len;
+    int len, rc;
     const char *file;
     char def_file[128];
     const NetdevDumpOptions *dump;
+    NetClientState *nc;
 
     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_DUMP);
     dump = opts->dump;

@@ -200,5 +191,13 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
         len = 65536;
     }
 
-    return net_dump_init(peer, "dump", name, file, len, errp);
+    nc = qemu_new_net_client(&net_dump_info, peer, "dump", name);
+    snprintf(nc->info_str, sizeof(nc->info_str),
+             "dump to %s (len=%d)", file, len);
+
+    rc = net_dump_state_init(DO_UPCAST(DumpState, nc, nc), file, len, errp);
+    if (rc) {
+        qemu_del_net_client(nc);
+    }
+    return rc;
 }

index 27083d4..afff78e 100644
@@ -31,7 +31,6 @@
 #include "hub.h"
 
 typedef struct DumpState {
-    NetClientState nc;
     int64_t start_ts;
     int fd;
     int pcap_caplen;

@@ -58,10 +57,8 @@ struct pcap_sf_pkthdr {
     uint32_t len;
 };
 
-static ssize_t dump_receive_iov(NetClientState *nc, const struct iovec *iov,
-                                int cnt)
+static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt)
 {
-    DumpState *s = DO_UPCAST(DumpState, nc, nc);
     struct pcap_sf_pkthdr hdr;
     int64_t ts;
     int caplen;

@@ -94,30 +91,12 @@ static ssize_t dump_receive_iov(NetClientState *nc, const struct iovec *iov,
     return size;
 }
 
-static ssize_t dump_receive(NetClientState *nc, const uint8_t *buf, size_t size)
-{
-    struct iovec iov = {
-        .iov_base = (void *)buf,
-        .iov_len = size
-    };
-    return dump_receive_iov(nc, &iov, 1);
-}
-
-static void dump_cleanup(NetClientState *nc)
+static void dump_cleanup(DumpState *s)
 {
-    DumpState *s = DO_UPCAST(DumpState, nc, nc);
-
     close(s->fd);
+    s->fd = -1;
 }
 
-static NetClientInfo net_dump_info = {
-    .type = NET_CLIENT_OPTIONS_KIND_DUMP,
-    .size = sizeof(DumpState),
-    .receive = dump_receive,
-    .receive_iov = dump_receive_iov,
-    .cleanup = dump_cleanup,
-};
-
 static int net_dump_state_init(DumpState *s, const char *filename,
                                int len, Error **errp)
 {

@@ -154,6 +133,49 @@ static int net_dump_state_init(DumpState *s, const char *filename,
     return 0;
 }
 
+/* Dumping via VLAN netclient */
+
+struct DumpNetClient {
+    NetClientState nc;
+    DumpState ds;
+};
+typedef struct DumpNetClient DumpNetClient;
+
+static ssize_t dumpclient_receive(NetClientState *nc, const uint8_t *buf,
+                                  size_t size)
+{
+    DumpNetClient *dc = DO_UPCAST(DumpNetClient, nc, nc);
+    struct iovec iov = {
+        .iov_base = (void *)buf,
+        .iov_len = size
+    };
+
+    return dump_receive_iov(&dc->ds, &iov, 1);
+}
+
+static ssize_t dumpclient_receive_iov(NetClientState *nc,
+                                      const struct iovec *iov, int cnt)
+{
+    DumpNetClient *dc = DO_UPCAST(DumpNetClient, nc, nc);
+
+    return dump_receive_iov(&dc->ds, iov, cnt);
+}
+
+static void dumpclient_cleanup(NetClientState *nc)
+{
+    DumpNetClient *dc = DO_UPCAST(DumpNetClient, nc, nc);
+
+    dump_cleanup(&dc->ds);
+}
+
+static NetClientInfo net_dump_info = {
+    .type = NET_CLIENT_OPTIONS_KIND_DUMP,
+    .size = sizeof(DumpNetClient),
+    .receive = dumpclient_receive,
+    .receive_iov = dumpclient_receive_iov,
+    .cleanup = dumpclient_cleanup,
+};
+
 int net_init_dump(const NetClientOptions *opts, const char *name,
                   NetClientState *peer, Error **errp)
 {

@@ -162,6 +184,7 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
     char def_file[128];
     const NetdevDumpOptions *dump;
     NetClientState *nc;
+    DumpNetClient *dnc;
 
     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_DUMP);
     dump = opts->dump;

@@ -195,7 +218,8 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
     snprintf(nc->info_str, sizeof(nc->info_str),
              "dump to %s (len=%d)", file, len);
 
-    rc = net_dump_state_init(DO_UPCAST(DumpState, nc, nc), file, len, errp);
+    dnc = DO_UPCAST(DumpNetClient, nc, nc);
+    rc = net_dump_state_init(&dnc->ds, file, len, errp);
     if (rc) {
         qemu_del_net_client(nc);
     }

index afff78e..5904f58 100644
@@ -28,7 +28,8 @@
 #include "qemu/iov.h"
 #include "qemu/log.h"
 #include "qemu/timer.h"
-#include "hub.h"
+#include "qapi/visitor.h"
+#include "net/filter.h"
 
 typedef struct DumpState {
     int64_t start_ts;

@@ -225,3 +226,129 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
     }
     return rc;
 }
+
+/* Dumping via filter */
+
+#define TYPE_FILTER_DUMP "filter-dump"
+
+#define FILTER_DUMP(obj) \
+    OBJECT_CHECK(NetFilterDumpState, (obj), TYPE_FILTER_DUMP)
+
+struct NetFilterDumpState {
+    NetFilterState nfs;
+    DumpState ds;
+    char *filename;
+    uint32_t maxlen;
+};
+typedef struct NetFilterDumpState NetFilterDumpState;
+
+static ssize_t filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr,
+                                       unsigned flags, const struct iovec *iov,
+                                       int iovcnt, NetPacketSent *sent_cb)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(nf);
+
+    dump_receive_iov(&nfds->ds, iov, iovcnt);
+    return 0;
+}
+
+static void filter_dump_cleanup(NetFilterState *nf)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(nf);
+
+    dump_cleanup(&nfds->ds);
+}
+
+static void filter_dump_setup(NetFilterState *nf, Error **errp)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(nf);
+
+    if (!nfds->filename) {
+        error_setg(errp, "dump filter needs 'file' property set!");
+        return;
+    }
+
+    net_dump_state_init(&nfds->ds, nfds->filename, nfds->maxlen, errp);
+}
+
+static void filter_dump_get_maxlen(Object *obj, Visitor *v, void *opaque,
+                                   const char *name, Error **errp)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(obj);
+    uint32_t value = nfds->maxlen;
+
+    visit_type_uint32(v, &value, name, errp);
+}
+
+static void filter_dump_set_maxlen(Object *obj, Visitor *v, void *opaque,
+                                   const char *name, Error **errp)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(obj);
+    Error *local_err = NULL;
+    uint32_t value;
+
+    visit_type_uint32(v, &value, name, &local_err);
+    if (local_err) {
+        goto out;
+    }
+    if (value == 0) {
+        error_setg(&local_err, "Property '%s.%s' doesn't take value '%u'",
+                   object_get_typename(obj), name, value);
+        goto out;
+    }
+    nfds->maxlen = value;
+
+out:
+    error_propagate(errp, local_err);
+}
+
+static char *file_dump_get_filename(Object *obj, Error **errp)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(obj);
+
+    return g_strdup(nfds->filename);
+}
+
+static void file_dump_set_filename(Object *obj, const char *value, Error **errp)
+{
+   NetFilterDumpState *nfds = FILTER_DUMP(obj);
+
+    g_free(nfds->filename);
+    nfds->filename = g_strdup(value);
+}
+
+static void filter_dump_instance_init(Object *obj)
+{
+    NetFilterDumpState *nfds = FILTER_DUMP(obj);
+
+    nfds->maxlen = 65536;
+
+    object_property_add(obj, "maxlen", "int", filter_dump_get_maxlen,
+                        filter_dump_set_maxlen, NULL, NULL, NULL);
+    object_property_add_str(obj, "file", file_dump_get_filename,
+                            file_dump_set_filename, NULL);
+}
+
+static void filter_dump_class_init(ObjectClass *oc, void *data)
+{
+    NetFilterClass *nfc = NETFILTER_CLASS(oc);
+
+    nfc->setup = filter_dump_setup;
+    nfc->cleanup = filter_dump_cleanup;
+    nfc->receive_iov = filter_dump_receive_iov;
+}
+
+static const TypeInfo filter_dump_info = {
+    .name = TYPE_FILTER_DUMP,
+    .parent = TYPE_NETFILTER,
+    .class_init = filter_dump_class_init,
+    .instance_init = filter_dump_instance_init,
+    .instance_size = sizeof(NetFilterDumpState),
+};
+
+static void filter_dump_register_types(void)
+{
+    type_register_static(&filter_dump_info);
+}
+
+type_init(filter_dump_register_types);

index 9be4d22..aa99ef3 100644
@@ -2761,8 +2761,12 @@ static bool object_create_initial(const char *type)
         return false;
     }
 
-    /* return false for concrete netfilters */
-    if (g_str_equal(type, "filter-buffer")) {
+    /*
+     * return false for concrete netfilters since
+     * they depend on netdevs already existing
+     */
+    if (g_str_equal(type, "filter-buffer") ||
+        g_str_equal(type, "filter-dump")) {
         return false;
     }