dpp: send presence announcements on StartEnrollee
The presence procedure implemented is a far cry from what the spec actually wants. There are two reason for this: a) the kernels offchannel support is not at a level where it will work without rather annoying work arounds, and b) doing the procedure outlined in the spec will result in terrible discovery performance. Because of this a simpler single channel announcement is done by default and the full presence procedure is left out until/if it is needed.
This commit is contained in:
James Prestwood
Denis Kenzior
parent
76d9a2e702
commit
683d3a3f04
243
src/dpp.c
243
src/dpp.c
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@ -24,15 +24,32 @@
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#include <config.h>
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#endif
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#include <errno.h>
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#include <ell/ell.h>
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#include "linux/nl80211.h"
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#include "src/dbus.h"
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#include "src/netdev.h"
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#include "src/module.h"
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#include "src/dpp-util.h"
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#include "src/band.h"
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#include "src/frame-xchg.h"
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#include "src/offchannel.h"
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#include "src/wiphy.h"
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#include "src/ie.h"
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#include "src/iwd.h"
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#include "src/util.h"
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static uint32_t netdev_watch;
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static struct l_genl_family *nl80211;
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static uint8_t broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
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enum dpp_state {
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DPP_STATE_NOTHING,
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DPP_STATE_PRESENCE,
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};
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struct dpp_sm {
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struct netdev *netdev;
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@ -48,6 +65,17 @@ struct dpp_sm {
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size_t nonce_len;
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struct l_ecc_scalar *boot_private;
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struct l_ecc_point *boot_public;
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enum dpp_state state;
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uint32_t *freqs;
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size_t freqs_len;
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size_t freqs_idx;
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uint32_t dwell;
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uint32_t current_freq;
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struct scan_freq_set *presence_list;
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uint32_t offchannel_id;
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};
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static void dpp_reset(struct dpp_sm *dpp)
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@ -56,6 +84,18 @@ static void dpp_reset(struct dpp_sm *dpp)
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l_free(dpp->uri);
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dpp->uri = NULL;
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}
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if (dpp->freqs) {
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l_free(dpp->freqs);
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dpp->freqs = NULL;
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}
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if (dpp->offchannel_id) {
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offchannel_cancel(dpp->wdev_id, dpp->offchannel_id);
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dpp->offchannel_id = 0;
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}
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dpp->state = DPP_STATE_NOTHING;
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}
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static void dpp_free(struct dpp_sm *dpp)
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@ -80,12 +120,106 @@ static void dpp_free(struct dpp_sm *dpp)
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l_free(dpp);
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}
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static void dpp_send_frame_cb(struct l_genl_msg *msg, void *user_data)
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{
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if (l_genl_msg_get_error(msg) < 0)
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l_error("Error sending frame");
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}
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static void dpp_send_frame(uint64_t wdev_id, struct iovec *iov, size_t iov_len,
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uint32_t freq)
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{
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struct l_genl_msg *msg;
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msg = l_genl_msg_new_sized(NL80211_CMD_FRAME, 512);
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l_genl_msg_append_attr(msg, NL80211_ATTR_WDEV, 8, &wdev_id);
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l_genl_msg_append_attr(msg, NL80211_ATTR_WIPHY_FREQ, 4, &freq);
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l_genl_msg_append_attr(msg, NL80211_ATTR_OFFCHANNEL_TX_OK, 0, NULL);
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l_genl_msg_append_attrv(msg, NL80211_ATTR_FRAME, iov, iov_len);
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l_debug("Sending frame on frequency %u", freq);
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if (!l_genl_family_send(nl80211, msg, dpp_send_frame_cb, NULL, NULL))
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l_error("Could not send CMD_FRAME");
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}
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static size_t dpp_append_attr(uint8_t *to, enum dpp_attribute_type type,
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void *attr, size_t attr_len)
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{
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l_put_le16(type, to);
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l_put_le16(attr_len, to + 2);
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memcpy(to + 4, attr, attr_len);
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return attr_len + 4;
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}
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static size_t dpp_build_header(const uint8_t *src, const uint8_t *dest,
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enum dpp_frame_type type,
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uint8_t buf[static 32])
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{
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uint8_t *ptr = buf + 24;
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memset(buf, 0, 32);
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l_put_le16(0x00d0, buf);
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memcpy(buf + 4, dest, 6);
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memcpy(buf + 10, src, 6);
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memcpy(buf + 16, broadcast, 6);
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*ptr++ = 0x04; /* Category: Public */
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*ptr++ = 0x09; /* Action: Vendor specific usage */
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memcpy(ptr, wifi_alliance_oui, 3);
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ptr += 3;
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*ptr++ = 0x1a; /* WiFi Alliance DPP OI type */
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*ptr++ = 1; /* Cryptosuite */
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*ptr++ = type;
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return ptr - buf;
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}
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static void dpp_presence_announce(struct dpp_sm *dpp)
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{
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struct netdev *netdev = dpp->netdev;
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uint8_t hdr[32];
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uint8_t attrs[32 + 4];
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uint8_t hash[32];
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uint8_t *ptr = attrs;
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const uint8_t *addr = netdev_get_address(netdev);
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struct iovec iov[2];
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iov[0].iov_len = dpp_build_header(addr, broadcast,
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DPP_FRAME_PRESENCE_ANNOUNCEMENT, hdr);
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iov[0].iov_base = hdr;
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dpp_hash(L_CHECKSUM_SHA256, hash, 2, "chirp", strlen("chirp"),
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dpp->pub_asn1, dpp->pub_asn1_len);
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ptr += dpp_append_attr(ptr, DPP_ATTR_RESPONDER_BOOT_KEY_HASH, hash, 32);
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iov[1].iov_base = attrs;
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iov[1].iov_len = ptr - attrs;
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l_debug("Sending presense annoucement on frequency %u and waiting %u",
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dpp->current_freq, dpp->dwell);
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dpp_send_frame(netdev_get_wdev_id(netdev), iov, 2, dpp->current_freq);
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}
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static void dpp_roc_started(void *user_data)
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{
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struct dpp_sm *dpp = user_data;
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dpp_presence_announce(dpp);
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}
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static void dpp_create(struct netdev *netdev)
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{
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struct l_dbus *dbus = dbus_get_bus();
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struct dpp_sm *dpp = l_new(struct dpp_sm, 1);
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dpp->netdev = netdev;
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dpp->state = DPP_STATE_NOTHING;
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dpp->wdev_id = netdev_get_wdev_id(netdev);
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dpp->curve = l_ecc_curve_from_ike_group(19);
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dpp->key_len = l_ecc_curve_get_scalar_bytes(dpp->curve);
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dpp->nonce_len = dpp_nonce_len_from_key_len(dpp->key_len);
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@ -123,6 +257,97 @@ static void dpp_netdev_watch(struct netdev *netdev,
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}
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}
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static void dpp_presence_timeout(int error, void *user_data)
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{
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struct dpp_sm *dpp = user_data;
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if (dpp->state != DPP_STATE_PRESENCE) {
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l_debug("DPP state changed, stopping presence announcements");
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dpp->freqs_idx = 0;
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return;
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}
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dpp->freqs_idx++;
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if (dpp->freqs_idx >= dpp->freqs_len) {
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l_debug("Max retries on presence announcements");
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dpp->freqs_idx = 0;
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}
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dpp->current_freq = dpp->freqs[dpp->freqs_idx];
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l_debug("Presence timeout, moving to next frequency %u, duration %u",
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dpp->current_freq, dpp->dwell);
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dpp->offchannel_id = offchannel_start(netdev_get_wdev_id(dpp->netdev),
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dpp->current_freq, dpp->dwell, dpp_roc_started,
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dpp, dpp_presence_timeout);
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}
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/*
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* EasyConnect 2.0 - 6.2.2
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*/
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static uint32_t *dpp_add_default_channels(struct dpp_sm *dpp, size_t *len_out)
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{
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struct wiphy *wiphy = wiphy_find_by_wdev(
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netdev_get_wdev_id(dpp->netdev));
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const struct scan_freq_set *list = wiphy_get_supported_freqs(wiphy);
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uint32_t freq;
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if (!dpp->presence_list)
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dpp->presence_list = scan_freq_set_new();
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scan_freq_set_add(dpp->presence_list, band_channel_to_freq(6,
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BAND_FREQ_2_4_GHZ));
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/*
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* "5 GHz: Channel 44 (5.220 GHz) if local regulations permit operation
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* only in the 5.150 - 5.250 GHz band and Channel 149 (5.745 GHz)
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* otherwise"
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*/
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freq = band_channel_to_freq(149, BAND_FREQ_5_GHZ);
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if (scan_freq_set_contains(list, freq))
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scan_freq_set_add(dpp->presence_list, freq);
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else
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scan_freq_set_add(dpp->presence_list,
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band_channel_to_freq(44, BAND_FREQ_5_GHZ));
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/* TODO: 60GHz: Channel 2 */
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return scan_freq_set_to_fixed_array(dpp->presence_list, len_out);
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}
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/*
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* TODO: There is an entire procedure defined in the spec where you increase
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* the ROC timeout with each unsuccessful iteration of channels, wait on channel
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* for long periods of time etc. Due to offchannel issues in the kernel this
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* procedure is not being fully implemented. In reality doing this would result
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* in quite terrible DPP performance anyways.
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*/
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static void dpp_start_presence(struct dpp_sm *dpp, uint32_t *limit_freqs,
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size_t limit_len)
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{
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uint32_t max_roc = wiphy_get_max_roc_duration(
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wiphy_find_by_wdev(dpp->wdev_id));
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if (2000 < max_roc)
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max_roc = 2000;
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if (limit_freqs) {
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dpp->freqs = l_memdup(limit_freqs, sizeof(uint32_t) * limit_len);
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dpp->freqs_len = limit_len;
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} else
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dpp->freqs = dpp_add_default_channels(dpp, &dpp->freqs_len);
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dpp->dwell = max_roc;
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dpp->freqs_idx = 0;
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dpp->current_freq = dpp->freqs[0];
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dpp->offchannel_id = offchannel_start(netdev_get_wdev_id(dpp->netdev),
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dpp->current_freq, dpp->dwell, dpp_roc_started,
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dpp, dpp_presence_timeout);
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}
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static struct l_dbus_message *dpp_dbus_start_enrollee(struct l_dbus *dbus,
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struct l_dbus_message *message,
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void *user_data)
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@ -131,12 +356,24 @@ static struct l_dbus_message *dpp_dbus_start_enrollee(struct l_dbus *dbus,
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uint32_t freq = band_channel_to_freq(6, BAND_FREQ_2_4_GHZ);
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struct l_dbus_message *reply;
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if (dpp->state != DPP_STATE_NOTHING)
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return dbus_error_busy(message);
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dpp->uri = dpp_generate_uri(dpp->pub_asn1, dpp->pub_asn1_len, 2,
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netdev_get_address(dpp->netdev), &freq,
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1, NULL, NULL);
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dpp->state = DPP_STATE_PRESENCE;
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l_debug("DPP Start Enrollee: %s", dpp->uri);
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/*
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* Going off spec here. Select a single channel to send presence
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* announcements on. This will be advertised in the URI. The full
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* presence procedure can be implemented if it is ever needed.
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*/
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dpp_start_presence(dpp, &freq, 1);
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reply = l_dbus_message_new_method_return(message);
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l_dbus_message_set_arguments(reply, "s", dpp->uri);
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@ -172,6 +409,12 @@ static void dpp_destroy_interface(void *user_data)
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static int dpp_init(void)
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{
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nl80211 = l_genl_family_new(iwd_get_genl(), NL80211_GENL_NAME);
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if (!nl80211) {
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l_error("Failed to obtain nl80211");
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return -EIO;
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}
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netdev_watch = netdev_watch_add(dpp_netdev_watch, NULL, NULL);
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l_dbus_register_interface(dbus_get_bus(), IWD_DPP_INTERFACE,
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