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Commit 86e8cf98 authored by Johannes Berg's avatar Johannes Berg
Browse files

nl80211: use small state buffer for wiphy_dump 



Avoid parsing the original dump message again and again by
allocating a small state struct that is used by the functions
involved in the dump, storing this struct in cb->args[0].
This reduces the memory allocation size as well.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent f93beba7

net/wireless/nl80211.c

+116 −94
Original line number Diff line number Diff line
@@ -1111,10 +1111,16 @@ nl80211_send_mgmt_stypes(struct sk_buff *msg, 
	return 0;

}



struct nl80211_dump_wiphy_state {

	s64 filter_wiphy;

	long start;

	long split_start, band_start, chan_start;

	bool split;

};



static int nl80211_send_wiphy(struct cfg80211_registered_device *dev,

			      struct sk_buff *msg, u32 portid, u32 seq,

			      int flags, bool split, long *split_start,

			      long *band_start, long *chan_start)

			      int flags, struct nl80211_dump_wiphy_state *state)

{

	void *hdr;

	struct nlattr *nl_bands, *nl_band;
@@ -1125,19 +1131,14 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
	int i;

	const struct ieee80211_txrx_stypes *mgmt_stypes =

				dev->wiphy.mgmt_stypes;

	long start = 0, start_chan = 0, start_band = 0;

	u32 features;



	hdr = nl80211hdr_put(msg, portid, seq, flags, NL80211_CMD_NEW_WIPHY);

	if (!hdr)

		return -ENOBUFS;



	/* allow always using the variables */

	if (!split) {

		split_start = &start;

		band_start = &start_band;

		chan_start = &start_chan;

	}

	if (WARN_ON(!state))

		return -EINVAL;



	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, dev->wiphy_idx) ||

	    nla_put_string(msg, NL80211_ATTR_WIPHY_NAME,
@@ -1146,7 +1147,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
			cfg80211_rdev_list_generation))

		goto nla_put_failure;



	switch (*split_start) {

	switch (state->split_start) {

	case 0:

		if (nla_put_u8(msg, NL80211_ATTR_WIPHY_RETRY_SHORT,

			       dev->wiphy.retry_short) ||
@@ -1192,8 +1193,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		    nla_put_flag(msg, WIPHY_FLAG_SUPPORTS_5_10_MHZ))

			goto nla_put_failure;



		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 1:

		if (nla_put(msg, NL80211_ATTR_CIPHER_SUITES,
@@ -1237,22 +1238,23 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
			}

		}



		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 2:

		if (nl80211_put_iftypes(msg, NL80211_ATTR_SUPPORTED_IFTYPES,

					dev->wiphy.interface_modes))

				goto nla_put_failure;

		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 3:

		nl_bands = nla_nest_start(msg, NL80211_ATTR_WIPHY_BANDS);

		if (!nl_bands)

			goto nla_put_failure;



		for (band = *band_start; band < IEEE80211_NUM_BANDS; band++) {

		for (band = state->band_start;

		     band < IEEE80211_NUM_BANDS; band++) {

			struct ieee80211_supported_band *sband;



			sband = dev->wiphy.bands[band];
@@ -1264,12 +1266,12 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
			if (!nl_band)

				goto nla_put_failure;



			switch (*chan_start) {

			switch (state->chan_start) {

			case 0:

				if (nl80211_send_band_rateinfo(msg, sband))

					goto nla_put_failure;

				(*chan_start)++;

				if (split)

				state->chan_start++;

				if (state->split)

					break;

			default:

				/* add frequencies */
@@ -1278,7 +1280,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
				if (!nl_freqs)

					goto nla_put_failure;



				for (i = *chan_start - 1;

				for (i = state->chan_start - 1;

				     i < sband->n_channels;

				     i++) {

					nl_freq = nla_nest_start(msg, i);
@@ -1287,26 +1289,27 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 


					chan = &sband->channels[i];



					if (nl80211_msg_put_channel(msg, chan,

								    split))

					if (nl80211_msg_put_channel(

							msg, chan,

							state->split))

						goto nla_put_failure;



					nla_nest_end(msg, nl_freq);

					if (split)

					if (state->split)

						break;

				}

				if (i < sband->n_channels)

					*chan_start = i + 2;

					state->chan_start = i + 2;

				else

					*chan_start = 0;

					state->chan_start = 0;

				nla_nest_end(msg, nl_freqs);

			}



			nla_nest_end(msg, nl_band);



			if (split) {

			if (state->split) {

				/* start again here */

				if (*chan_start)

				if (state->chan_start)

					band--;

				break;

			}
@@ -1314,14 +1317,14 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		nla_nest_end(msg, nl_bands);



		if (band < IEEE80211_NUM_BANDS)

			*band_start = band + 1;

			state->band_start = band + 1;

		else

			*band_start = 0;

			state->band_start = 0;



		/* if bands & channels are done, continue outside */

		if (*band_start == 0 && *chan_start == 0)

			(*split_start)++;

		if (split)

		if (state->band_start == 0 && state->chan_start == 0)

			state->split_start++;

		if (state->split)

			break;

	case 4:

		nl_cmds = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_COMMANDS);
@@ -1387,7 +1390,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		}

		CMD(start_p2p_device, START_P2P_DEVICE);

		CMD(set_mcast_rate, SET_MCAST_RATE);

		if (split) {

		if (state->split) {

			CMD(crit_proto_start, CRIT_PROTOCOL_START);

			CMD(crit_proto_stop, CRIT_PROTOCOL_STOP);

		}
@@ -1411,8 +1414,8 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		}



		nla_nest_end(msg, nl_cmds);

		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 5:

		if (dev->ops->remain_on_channel &&
@@ -1428,29 +1431,30 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 


		if (nl80211_send_mgmt_stypes(msg, mgmt_stypes))

			goto nla_put_failure;

		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 6:

#ifdef CONFIG_PM

		if (nl80211_send_wowlan(msg, dev, split))

		if (nl80211_send_wowlan(msg, dev, state->split))

			goto nla_put_failure;

		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

#else

		(*split_start)++;

		state->split_start++;

#endif

	case 7:

		if (nl80211_put_iftypes(msg, NL80211_ATTR_SOFTWARE_IFTYPES,

					dev->wiphy.software_iftypes))

			goto nla_put_failure;



		if (nl80211_put_iface_combinations(&dev->wiphy, msg, split))

		if (nl80211_put_iface_combinations(&dev->wiphy, msg,

						   state->split))

			goto nla_put_failure;



		(*split_start)++;

		if (split)

		state->split_start++;

		if (state->split)

			break;

	case 8:

		if ((dev->wiphy.flags & WIPHY_FLAG_HAVE_AP_SME) &&
@@ -1464,7 +1468,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		 * dump is split, otherwise it makes it too big. Therefore

		 * only advertise it in that case.

		 */

		if (split)

		if (state->split)

			features |= NL80211_FEATURE_ADVERTISE_CHAN_LIMITS;

		if (nla_put_u32(msg, NL80211_ATTR_FEATURE_FLAGS, features))

			goto nla_put_failure;
@@ -1491,7 +1495,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
		 * case we'll continue with more data in the next round,

		 * but break unconditionally so unsplit data stops here.

		 */

		(*split_start)++;

		state->split_start++;

		break;

	case 9:

		if (dev->wiphy.extended_capabilities &&
@@ -1510,7 +1514,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
			goto nla_put_failure;



		/* done */

		*split_start = 0;

		state->split_start = 0;

		break;

	}

	return genlmsg_end(msg, hdr);
@@ -1520,66 +1524,76 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *dev, 
	return -EMSGSIZE;

}



static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)

static int nl80211_dump_wiphy_parse(struct sk_buff *skb,

				    struct netlink_callback *cb,

				    struct nl80211_dump_wiphy_state *state)

{

	int idx = 0, ret;

	int start = cb->args[0];

	struct cfg80211_registered_device *dev;

	s64 filter_wiphy = -1;

	bool split = false;

	struct nlattr **tb;

	int res;



	/* will be zeroed in nlmsg_parse() */

	tb = kmalloc(sizeof(*tb) * (NL80211_ATTR_MAX + 1), GFP_KERNEL);

	if (!tb)

		return -ENOMEM;

	struct nlattr **tb = nl80211_fam.attrbuf;

	int ret = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,

			      tb, nl80211_fam.maxattr, nl80211_policy);

	/* ignore parse errors for backward compatibility */

	if (ret)

		return 0;



	rtnl_lock();

	res = nlmsg_parse(cb->nlh, GENL_HDRLEN + nl80211_fam.hdrsize,

			  tb, NL80211_ATTR_MAX, nl80211_policy);

	if (res == 0) {

		split = tb[NL80211_ATTR_SPLIT_WIPHY_DUMP];

	state->split = tb[NL80211_ATTR_SPLIT_WIPHY_DUMP];

	if (tb[NL80211_ATTR_WIPHY])

			filter_wiphy = nla_get_u32(tb[NL80211_ATTR_WIPHY]);

		state->filter_wiphy = nla_get_u32(tb[NL80211_ATTR_WIPHY]);

	if (tb[NL80211_ATTR_WDEV])

			filter_wiphy = nla_get_u64(tb[NL80211_ATTR_WDEV]) >> 32;

		state->filter_wiphy = nla_get_u64(tb[NL80211_ATTR_WDEV]) >> 32;

	if (tb[NL80211_ATTR_IFINDEX]) {

		struct net_device *netdev;

		struct cfg80211_registered_device *rdev;

		int ifidx = nla_get_u32(tb[NL80211_ATTR_IFINDEX]);



		netdev = dev_get_by_index(sock_net(skb->sk), ifidx);

			if (!netdev) {

				rtnl_unlock();

				kfree(tb);

		if (!netdev)

			return -ENODEV;

			}

		if (netdev->ieee80211_ptr) {

				dev = wiphy_to_dev(

			rdev = wiphy_to_dev(

				netdev->ieee80211_ptr->wiphy);

				filter_wiphy = dev->wiphy_idx;

			state->filter_wiphy = rdev->wiphy_idx;

		}

		dev_put(netdev);

	}



	return 0;

}



static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)

{

	int idx = 0, ret;

	struct nl80211_dump_wiphy_state *state = (void *)cb->args[0];

	struct cfg80211_registered_device *dev;



	rtnl_lock();

	if (!state) {

		state = kzalloc(sizeof(*state), GFP_KERNEL);

		if (!state)

			return -ENOMEM;

		state->filter_wiphy = -1;

		ret = nl80211_dump_wiphy_parse(skb, cb, state);

		if (ret) {

			kfree(state);

			rtnl_unlock();

			return ret;

		}

		cb->args[0] = (long)state;

	}

	kfree(tb);



	list_for_each_entry(dev, &cfg80211_rdev_list, list) {

		if (!net_eq(wiphy_net(&dev->wiphy), sock_net(skb->sk)))

			continue;

		if (++idx <= start)

		if (++idx <= state->start)

			continue;

		if (filter_wiphy != -1 && dev->wiphy_idx != filter_wiphy)

		if (state->filter_wiphy != -1 &&

		    state->filter_wiphy != dev->wiphy_idx)

			continue;

		/* attempt to fit multiple wiphy data chunks into the skb */

		do {

			ret = nl80211_send_wiphy(dev, skb,

						 NETLINK_CB(cb->skb).portid,

						 cb->nlh->nlmsg_seq,

						 NLM_F_MULTI,

						 split, &cb->args[1],

						 &cb->args[2],

						 &cb->args[3]);

						 NLM_F_MULTI, state);

			if (ret < 0) {

				/*

				 * If sending the wiphy data didn't fit (ENOBUFS
@@ -1604,27 +1618,34 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb) 
				idx--;

				break;

			}

		} while (cb->args[1] > 0);

		} while (state->split_start > 0);

		break;

	}

	rtnl_unlock();



	cb->args[0] = idx;

	state->start = idx;



	return skb->len;

}



static int nl80211_dump_wiphy_done(struct netlink_callback *cb)

{

	kfree((void *)cb->args[0]);

	return 0;

}



static int nl80211_get_wiphy(struct sk_buff *skb, struct genl_info *info)

{

	struct sk_buff *msg;

	struct cfg80211_registered_device *dev = info->user_ptr[0];

	struct nl80211_dump_wiphy_state state = {};



	msg = nlmsg_new(4096, GFP_KERNEL);

	if (!msg)

		return -ENOMEM;



	if (nl80211_send_wiphy(dev, msg, info->snd_portid, info->snd_seq, 0,

			       false, NULL, NULL, NULL) < 0) {

			       &state) < 0) {

		nlmsg_free(msg);

		return -ENOBUFS;

	}
@@ -8418,6 +8439,7 @@ static struct genl_ops nl80211_ops[] = { 
		.cmd = NL80211_CMD_GET_WIPHY,

		.doit = nl80211_get_wiphy,

		.dumpit = nl80211_dump_wiphy,

		.done = nl80211_dump_wiphy_done,

		.policy = nl80211_policy,

		/* can be retrieved by unprivileged users */

		.internal_flags = NL80211_FLAG_NEED_WIPHY |
@@ -9038,13 +9060,13 @@ static struct genl_multicast_group nl80211_regulatory_mcgrp = { 
void nl80211_notify_dev_rename(struct cfg80211_registered_device *rdev)

{

	struct sk_buff *msg;

	struct nl80211_dump_wiphy_state state = {};



	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);

	if (!msg)

		return;



	if (nl80211_send_wiphy(rdev, msg, 0, 0, 0,

			       false, NULL, NULL, NULL) < 0) {

	if (nl80211_send_wiphy(rdev, msg, 0, 0, 0, &state) < 0) {

		nlmsg_free(msg);

		return;

	}