Add debug command to receive and print selected management frames.
Frames are selected by their type and pattern containing the first
several bytes of the frame that should match.
Note that Linux wireless core does not support multiple listeners
for management frames. So this debug command can be used together
with hostapd or other wireless software only in the case if it
subscribes for different set of management frames.
Format:
$ iw dev <devname> frame <type> <pattern> [frame <type> <pattern>]* [count <frames>]
Example:
$ iw dev wlan0 mgmt dump frame 40 00 frame 40 01:02 count 10
Frame type is supplied as hex w/o leading 0x. Frame pattern is supplied
as hex pattern of the form aa:bb:cc w/o leading 0x as well.
Count is a number of frames to receive.
Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@xxxxxxxxxxxxx>
-------
Changes v1->v2:
- fix rssi type
- rename command to avoid confusion: dump rather than capture
- add note to commit message: multiple mgmt frame listeners are not supported
---
Makefile | 2 +-
mgmt.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 151 insertions(+), 1 deletion(-)
create mode 100644 mgmt.c
diff --git a/Makefile b/Makefile
index e61825e..38d782d 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ OBJS = iw.o genl.o event.o info.o phy.o \
interface.o ibss.o station.o survey.o util.o ocb.o \
mesh.o mpath.o mpp.o scan.o reg.o version.o \
reason.o status.o connect.o link.o offch.o ps.o cqm.o \
- bitrate.o wowlan.o coalesce.o roc.o p2p.o vendor.o
+ bitrate.o wowlan.o coalesce.o roc.o p2p.o vendor.o mgmt.o
OBJS += sections.o
OBJS-$(HWSIM) += hwsim.o
diff --git a/mgmt.c b/mgmt.c
new file mode 100644
index 0000000..60f544b
--- /dev/null
+++ b/mgmt.c
@@ -0,0 +1,150 @@
+#include <string.h>
+#include <errno.h>
+
+#include <netlink/genl/genl.h>
+#include <netlink/genl/family.h>
+#include <netlink/genl/ctrl.h>
+#include <netlink/msg.h>
+#include <netlink/attr.h>
+
+#include "nl80211.h"
+#include "iw.h"
+
+SECTION(mgmt);
+
+static int seq_handler(struct nl_msg *msg, void *arg)
+{
+ return NL_OK;
+}
+
+static int dump_mgmt_frame(struct nl_msg *msg, void *arg)
+{
+ struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+ struct nlattr *tb_msg[NL80211_ATTR_MAX + 1];
+
+ nla_parse(tb_msg, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+ genlmsg_attrlen(gnlh, 0), NULL);
+
+ if (tb_msg[NL80211_ATTR_WIPHY_FREQ]) {
+ uint32_t freq = nla_get_u32(tb_msg[NL80211_ATTR_WIPHY_FREQ]);
+ printf("freq %u MHz\n", freq);
+ }
+
+ if (tb_msg[NL80211_ATTR_RX_SIGNAL_DBM]) {
+ /* nl80211_send_mgmt sends signed dBm value as u32 */
+ int dbm = nla_get_u32(tb_msg[NL80211_ATTR_RX_SIGNAL_DBM]);
+ printf("rssi %d dBm\n", dbm);
+ }
+
+ if (tb_msg[NL80211_ATTR_FRAME]) {
+ int len = nla_len(tb_msg[NL80211_ATTR_FRAME]);
+ uint8_t *data = nla_data(tb_msg[NL80211_ATTR_FRAME]);
+ iw_hexdump("mgmt", data, len);
+ }
+
+ return 0;
+}
+
+static int register_mgmt_frame(struct nl80211_state *state,
+ struct nl_msg *msg, int argc, char **argv,
+ enum id_input id)
+{
+ unsigned int type;
+ unsigned char *match;
+ size_t match_len;
+ int ret;
+
+ ret = sscanf(argv[0], "%x", &type);
+ if (ret != 1) {
+ printf("invalid frame type: %s\n", argv[0]);
+ return 2;
+ }
+
+ match = parse_hex(argv[1], &match_len);
+ if (!match) {
+ printf("invalid frame pattern: %s\n", argv[1]);
+ return 2;
+ }
+
+ NLA_PUT_U16(msg, NL80211_ATTR_FRAME_TYPE, type);
+ NLA_PUT(msg, NL80211_ATTR_FRAME_MATCH, match_len, match);
+
+ return 0;
+
+nla_put_failure:
+ return -ENOBUFS;
+}
+
+static int handle_mgmt_reg(struct nl80211_state *state,
+ struct nl_msg *msg, int argc,
+ char **argv, enum id_input id)
+{
+ return register_mgmt_frame(state, msg, argc, argv, id);
+}
+
+HIDDEN(mgmt, reg, "", NL80211_CMD_REGISTER_FRAME, 0, CIB_NETDEV, handle_mgmt_reg);
+
+static int handle_mgmt_dump(struct nl80211_state *state,
+ struct nl_msg *msg, int argc,
+ char **argv, enum id_input id)
+{
+ struct nl_cb *mgmt_cb;
+ char *ndev = argv[0];
+ int mgmt_argc = 5;
+ char **mgmt_argv;
+ unsigned int count = 0;
+ int err = 0;
+ int i;
+
+ mgmt_argv = calloc(mgmt_argc, sizeof(char*));
+ if (!mgmt_argv)
+ return -ENOMEM;
+
+ mgmt_argv[0] = ndev;
+ mgmt_argv[1] = "mgmt";
+ mgmt_argv[2] = "reg";
+
+ for (i = 3; i < argc; i += 3) {
+ if (strcmp(argv[i], "count") == 0) {
+ count = 1 + atoi(argv[i + 1]);
+ break;
+ }
+
+ if (strcmp(argv[i], "frame") != 0) {
+ err = 1;
+ goto out;
+ }
+
+ mgmt_argv[3] = argv[i + 1];
+ mgmt_argv[4] = argv[i + 2];
+
+ err = handle_cmd(state, II_NETDEV, mgmt_argc, mgmt_argv);
+ if (err)
+ goto out;
+ }
+
+ mgmt_cb = nl_cb_alloc(iw_debug ? NL_CB_DEBUG : NL_CB_DEFAULT);
+ if (!mgmt_cb) {
+ err = 1;
+ goto out;
+ }
+
+ /* need to turn off sequence number checking */
+ nl_cb_set(mgmt_cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, seq_handler, NULL);
+ nl_cb_set(mgmt_cb, NL_CB_VALID, NL_CB_CUSTOM, dump_mgmt_frame, NULL);
+
+ while (--count)
+ nl_recvmsgs(state->nl_sock, mgmt_cb);
+
+ nl_cb_put(mgmt_cb);
+out:
+ free(mgmt_argv);
+ return err;
+}
+
+COMMAND(mgmt, dump, "frame <type as hex ab> <pattern as hex ab:cd:..> [frame <type> <pattern>]* [count <frames>]",
+ 0, 0, CIB_NETDEV, handle_mgmt_dump,
+ "Register for receiving certain mgmt frames and print them.\n"
+ "Frames are selected by their type and pattern containing\n"
+ "the first several bytes of the frame that should match.\n\n"
+ "Example: iw dev wlan0 mgmt dump frame 40 00 frame 40 01:02 count 10\n");
--
2.11.0
