netfilter: qtaguid: add tag delete command, expand stats output.

* Add a new ctrl command to delete stored data.
  d <acct_tag> [<uid>]
The uid will default to the running process's.
The accounting tag can be 0, in which case all counters and socket tags
associated with the uid will be cleared.

* Simplify the ctrl command handling at the expense of duplicate code.
This should make it easier to maintain.

* /proc/net/xt_qtaguid/stats now returns more stats
  idx iface acct_tag_hex uid_tag_int
  {rx,tx}_{bytes,packets}
  {rx,tx}_{tcp,udp,other}_{bytes,packets}
the {rx,tx}_{bytes,packets} are the totals.

* re-tagging will now allow changing the uid.

Change-Id: I9594621543cefeab557caa3d68a22a3eb320466d
Signed-off-by: JP Abgrall <jpa@google.com>

1 files changed, 291 insertions, 123 deletions

diff --git a/net/netfilter/xt_qtaguid.c b/net/netfilter/xt_qtaguid.c
index 49ed432d793c..0aa33daabedc 100644
--- a/net/netfilter/xt_qtaguid.c
+++ b/net/netfilter/xt_qtaguid.c
@@ -8,7 +8,8 @@
  * published by the Free Software Foundation.
  */
 
-/* TODO: support ipv6 for iface_stat */
+/* TODO: support ipv6 for iface_stat.
+ * Currently if an iface is only v6 it will not have stats collected. */
 
 #include <linux/file.h>
 #include <linux/inetdevice.h>
@@ -96,9 +97,6 @@ struct tag_stat {
 	struct proc_dir_entry *proc_ptr;
 };
 
-static LIST_HEAD(iface_stat_list);
-static DEFINE_SPINLOCK(iface_stat_list_lock);
-
 struct iface_stat {
 	struct list_head list;
 	char *ifname;
@@ -113,9 +111,8 @@ struct iface_stat {
 	spinlock_t tag_stat_list_lock;
 };
 
-
-static struct rb_root sock_tag_tree = RB_ROOT;
-static DEFINE_SPINLOCK(sock_tag_list_lock);
+static LIST_HEAD(iface_stat_list);
+static DEFINE_SPINLOCK(iface_stat_list_lock);
 
 /*
  * Track tag that this socket is transferring data for, and not necesseraly
@@ -128,6 +125,9 @@ struct sock_tag {
 	tag_t tag;
 };
 
+static struct rb_root sock_tag_tree = RB_ROOT;
+static DEFINE_SPINLOCK(sock_tag_list_lock);
+
 static bool qtaguid_mt(const struct sk_buff *skb, struct xt_action_param *par);
 
 /*----------------------------------------------*/
@@ -181,6 +181,14 @@ static inline uint64_t dc_sum_bytes(struct data_counters *counters,
 		+ counters->bpc[direction][IFS_PROTO_OTHER].bytes;
 }
 
+static inline uint64_t dc_sum_packets(struct data_counters *counters,
+				      enum ifs_tx_rx direction)
+{
+	return counters->bpc[direction][IFS_TCP].packets
+		+ counters->bpc[direction][IFS_UDP].packets
+		+ counters->bpc[direction][IFS_PROTO_OTHER].packets;
+}
+
 static struct tag_stat *tag_stat_tree_search(struct rb_root *root, tag_t tag)
 {
 	struct rb_node *node = root->rb_node;
@@ -397,12 +405,11 @@ void iface_stat_create(const struct net_device *net_dev)
 		return;
 	}
 
-	new_iface = kmalloc(sizeof(*new_iface), GFP_KERNEL);
+	new_iface = kzalloc(sizeof(*new_iface), GFP_KERNEL);
 	if (new_iface == NULL) {
 		pr_err("iface_stat: create(): failed to alloc iface_stat\n");
 		return;
 	}
-	memset(new_iface, 0, sizeof(*new_iface));
 	new_iface->ifname = kstrdup(ifname, GFP_KERNEL);
 	if (new_iface->ifname == NULL) {
 		pr_err("iface_stat: create(): failed to alloc ifname\n");
@@ -531,12 +538,11 @@ static struct tag_stat *create_if_tag_stat(struct iface_stat *iface_entry,
 	pr_debug("iface_stat: create_if_tag_stat(): ife=%p tag=0x%llx"
 		 " (uid=%d)\n",
 		 iface_entry, tag, get_uid_from_tag(tag));
-	new_tag_stat_entry = kmalloc(sizeof(*new_tag_stat_entry), GFP_ATOMIC);
+	new_tag_stat_entry = kzalloc(sizeof(*new_tag_stat_entry), GFP_ATOMIC);
 	if (!new_tag_stat_entry) {
 		pr_err("iface_stat: failed to alloc new tag entry\n");
 		goto done;
 	}
-	memset(new_tag_stat_entry, 0, sizeof(*new_tag_stat_entry));
 	new_tag_stat_entry->tag = tag;
 	tag_stat_tree_insert(new_tag_stat_entry, &iface_entry->tag_stat_tree);
 done:
@@ -852,7 +858,7 @@ static bool qtaguid_mt(const struct sk_buff *skb, struct xt_action_param *par)
 		pr_debug("xt_qtaguid[%d]: leaving (sk?sk->sk_socket)=%p\n",
 			par->hooknum,
 			sk ? sk->sk_socket : NULL);
-		res =  (info->match ^ info->invert) == 0;
+		res = (info->match ^ info->invert) == 0;
 		goto put_sock_ret_res;
 	} else if (info->match & info->invert & XT_QTAGUID_SOCKET) {
 		res = false;
@@ -922,7 +928,7 @@ static int qtaguid_ctrl_proc_read(char *page, char **num_items_returned,
 	struct rb_node *node;
 	int item_index = 0;
 
-	pr_debug("xt_qtaguid:proc ctrl page=%p off=%ld char_count=%d *eof=%d\n",
+	pr_debug("xt_qtaguid: proc ctrl page=%p off=%ld char_count=%d *eof=%d\n",
 		page, items_to_skip, char_count, *eof);
 
 	if (*eof)
@@ -934,7 +940,7 @@ static int qtaguid_ctrl_proc_read(char *page, char **num_items_returned,
 	     node = rb_next(node)) {
 		if (item_index++ < items_to_skip)
 			continue;
-		sock_tag_entry =  rb_entry(node, struct sock_tag, node);
+		sock_tag_entry = rb_entry(node, struct sock_tag, node);
 		uid = get_uid_from_tag(sock_tag_entry->tag);
 		pr_debug("xt_qtaguid: proc_read(): sk=%p tag=0x%llx (uid=%d)\n",
 			sock_tag_entry->sk,
@@ -957,7 +963,103 @@ static int qtaguid_ctrl_proc_read(char *page, char **num_items_returned,
 	return outp - page;
 }
 
-static int qtaguid_ctrl_parse(const char *input, int count)
+/* Delete socket tags, and stat tags associated with a given
+ * accouting tag and uid. */
+static int ctrl_cmd_delete(const char *input)
+{
+	char cmd;
+	uid_t uid = 0;
+	uid_t entry_uid;
+	tag_t acct_tag = 0;
+	tag_t tag;
+	int res, argc;
+	unsigned long flags, flags2;
+	struct iface_stat *iface_entry;
+	struct rb_node *node;
+	struct sock_tag *st_entry;
+	struct tag_stat *ts_entry;
+
+	pr_debug("xt_qtaguid: ctrl_delete(%s): entered\n", input);
+	argc = sscanf(input, "%c %llu %u", &cmd, &acct_tag, &uid);
+	pr_debug("xt_qtaguid: ctrl_delete(%s): argc=%d cmd=%c "
+		 "acct_tag=0x%llx uid=%u\n", input, argc, cmd,
+		 acct_tag, uid);
+	if (argc < 2) {
+		res = -EINVAL;
+		goto err;
+	}
+	if (!valid_atag(acct_tag)) {
+		pr_info("xt_qtaguid: ctrl_delete(%s): invalid tag\n", input);
+		res = -EINVAL;
+		goto err;
+	}
+	if (argc < 3)
+		uid = current_fsuid();
+
+	/* TODO: check that the uid == current_fsuid()
+	 * except for special uid/gid. */
+
+	spin_lock_irqsave(&sock_tag_list_lock, flags);
+	node = rb_first(&sock_tag_tree);
+	while (node) {
+		st_entry = rb_entry(node, struct sock_tag, node);
+		entry_uid = get_uid_from_tag(st_entry->tag);
+		node = rb_next(node);
+		if (entry_uid != uid)
+			continue;
+
+		if (!acct_tag || st_entry->tag == tag) {
+			pr_debug("xt_qtaguid: ctrl_delete(): "
+				 "erase sk=%p tag=0x%llx (uid=%d)\n",
+				 st_entry->sk,
+				 st_entry->tag,
+				 entry_uid);
+			rb_erase(&ts_entry->node, &sock_tag_tree);
+			kfree(st_entry);
+		}
+	}
+	spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+
+	/* If acct_tag is 0, then all entries belonging to uid are
+	 * erased. */
+	tag = combine_atag_with_uid(acct_tag, uid);
+	spin_lock_irqsave(&iface_stat_list_lock, flags);
+	list_for_each_entry(iface_entry, &iface_stat_list, list) {
+
+		spin_lock_irqsave(&iface_entry->tag_stat_list_lock, flags2);
+		node = rb_first(&iface_entry->tag_stat_tree);
+		while (node) {
+			ts_entry = rb_entry(node, struct tag_stat, node);
+			entry_uid = get_uid_from_tag(ts_entry->tag);
+			node = rb_next(node);
+			if (entry_uid != uid)
+				continue;
+			if (!acct_tag || ts_entry->tag == tag) {
+				pr_debug("xt_qtaguid: ctrl_delete(): erase "
+					 "%s 0x%llx %u\n",
+					 iface_entry->ifname,
+					 get_atag_from_tag(ts_entry->tag),
+					 entry_uid);
+				rb_erase(&ts_entry->node,
+					 &iface_entry->tag_stat_tree);
+				kfree(ts_entry);
+			}
+		}
+		spin_unlock_irqrestore(&iface_entry->tag_stat_list_lock,
+				       flags2);
+
+	}
+	spin_unlock_irqrestore(&iface_stat_list_lock, flags);
+
+	res = 0;
+
+err:
+	pr_debug("xt_qtaguid: ctrl_delete(%s) res=%d\n", input, res);
+	return res;
+}
+
+
+static int ctrl_cmd_tag(const char *input)
 {
 	char cmd;
 	int sock_fd = 0;
@@ -968,117 +1070,139 @@ static int qtaguid_ctrl_parse(const char *input, int count)
 	struct sock_tag *sock_tag_entry;
 	unsigned long flags;
 
-	pr_debug("xt_qtaguid: ctrl(%s): entered\n", input);
 	/* Unassigned args will get defaulted later. */
-	/* TODO: get acct_tag_str, keep a list of available tags for the
-	 * uid, use num as acct_tag. */
 	argc = sscanf(input, "%c %d %llu %u", &cmd, &sock_fd, &acct_tag, &uid);
-	pr_debug("xt_qtaguid: ctrl(%s): argc=%d cmd=%c sock_fd=%d "
-		"acct_tag=0x%llx uid=%u\n", input, argc, cmd, sock_fd,
-		acct_tag, uid);
+	pr_debug("xt_qtaguid: ctrl_tag(%s): argc=%d cmd=%c sock_fd=%d "
+		 "acct_tag=0x%llx uid=%u\n", input, argc, cmd, sock_fd,
+		 acct_tag, uid);
+	if (argc < 2) {
+		res = -EINVAL;
+		goto err;
+	}
+	el_socket = sockfd_lookup(sock_fd, &res);
+	if (!el_socket) {
+		pr_info("xt_qtaguid: ctrl_tag(%s): failed to lookup"
+			" sock_fd=%d err=%d\n", input, sock_fd, res);
+		goto err;
+	}
+	if (argc < 3) {
+		acct_tag = 0;
+	} else if (!valid_atag(acct_tag)) {
+		pr_info("xt_qtaguid: ctrl_tag(%s): invalid tag\n", input);
+		res = -EINVAL;
+		goto err;
+	}
+	if (argc < 4)
+		uid = current_fsuid();
 
-	/* Collect params for commands */
-	switch (cmd) {
-	case 't':
-	case 'u':
-		if (argc < 2) {
-			res = -EINVAL;
-			goto err;
-		}
-		el_socket = sockfd_lookup(sock_fd, &res);
-		if (!el_socket) {
-			pr_info("xt_qtaguid: ctrl(%s): failed to lookup"
-				" sock_fd=%d err=%d\n", input, sock_fd, res);
+	spin_lock_irqsave(&sock_tag_list_lock, flags);
+	sock_tag_entry = get_sock_stat_nl(el_socket->sk);
+	if (sock_tag_entry) {
+		/* TODO: check that the uid == current_fsuid()
+		 * except for special uid/gid. */
+		sock_tag_entry->tag = combine_atag_with_uid(acct_tag,
+							    uid);
+	} else {
+		spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+		sock_tag_entry = kzalloc(sizeof(*sock_tag_entry),
+					 GFP_KERNEL);
+		if (!sock_tag_entry) {
+			res = -ENOMEM;
 			goto err;
 		}
+		sock_tag_entry->sk = el_socket->sk;
+		/* TODO: check that uid==current_fsuid() except
+		 * for special uid/gid. */
+		sock_tag_entry->tag = combine_atag_with_uid(acct_tag,
+							    uid);
 		spin_lock_irqsave(&sock_tag_list_lock, flags);
-		/* TODO: optim: pass in the current_fsuid() to do lookups
-		 * as look ups will always be initiated form the same uid. */
-		sock_tag_entry = get_sock_stat_nl(el_socket->sk);
-		if (!sock_tag_entry)
-			spin_unlock_irqrestore(&sock_tag_list_lock, flags);
-		/* HERE: The lock is held if there was a matching sock tag entry */
-		break;
-	default:
+		sock_tag_tree_insert(sock_tag_entry, &sock_tag_tree);
+	}
+	spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+
+	pr_debug("xt_qtaguid: tag: sock_tag_entry->sk=%p "
+		 "...->tag=0x%llx (uid=%u)\n",
+		 sock_tag_entry->sk, sock_tag_entry->tag,
+		 get_uid_from_tag(sock_tag_entry->tag));
+	res = 0;
+
+err:
+	pr_debug("xt_qtaguid: ctrl_tag(%s) res=%d\n", input, res);
+	return res;
+}
+
+
+static int ctrl_cmd_untag(const char *input)
+{
+	char cmd;
+	int sock_fd = 0;
+	struct socket *el_socket;
+	int res, argc;
+	struct sock_tag *sock_tag_entry;
+	unsigned long flags;
+
+	pr_debug("xt_qtaguid: ctrl_untag(%s): entered\n", input);
+	argc = sscanf(input, "%c %d", &cmd, &sock_fd);
+	pr_debug("xt_qtaguid: ctrl_untag(%s): argc=%d cmd=%c sock_fd=%d\n",
+		 input, argc, cmd, sock_fd);
+	if (argc < 2) {
 		res = -EINVAL;
 		goto err;
 	}
-	/* HERE: The lock is held if there was a matching sock tag entry */
+	el_socket = sockfd_lookup(sock_fd, &res);
+	if (!el_socket) {
+		pr_info("xt_qtaguid: ctrl_untag(%s): failed to lookup"
+			" sock_fd=%d err=%d\n", input, sock_fd, res);
+		goto err;
+	}
+	spin_lock_irqsave(&sock_tag_list_lock, flags);
+	sock_tag_entry = get_sock_stat_nl(el_socket->sk);
+	if (!sock_tag_entry) {
+		spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+		res = -EINVAL;
+		goto err;
+	}
+
+	/* TODO: check that the uid==current_fsuid()
+	 * except for special uid/gid. */
+	rb_erase(&sock_tag_entry->node, &sock_tag_tree);
+	spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+	kfree(sock_tag_entry);
+
+	res = 0;
+err:
+	pr_debug("xt_qtaguid: ctrl_untag(%s): res=%d\n", input, res);
+	return res;
+}
 
-	/* Process commands */
+static int qtaguid_ctrl_parse(const char *input, int count)
+{
+	char cmd;
+	int res;
+
+	pr_debug("xt_qtaguid: ctrl(%s): entered\n", input);
+	cmd = input[0];
+	/* Collect params for commands */
 	switch (cmd) {
+	case 'd':
+		res = ctrl_cmd_delete(input);
+		break;
 
 	case 't':
-		if (argc < 2) {
-			res = -EINVAL;
-			/* HERE: The lock is held if there was a matching sock
-			 * tag entry */
-			goto err_unlock;
-		}
-		if (argc < 3) {
-			acct_tag = 0;
-		} else if (!valid_atag(acct_tag)) {
-			res = -EINVAL;
-			/* HERE: The lock is held if there was a matching sock
-			 * tag entry */
-			goto err_unlock;
-		}
-		if (argc < 4)
-			uid = current_fsuid();
-		if (!sock_tag_entry) {
-			/* HERE: There is no lock held because there was no
-			 * sock tag entry */
-			sock_tag_entry = kmalloc(sizeof(*sock_tag_entry),
-						GFP_KERNEL);
-			if (!sock_tag_entry) {
-				res = -ENOMEM;
-				goto err;
-			}
-			memset(sock_tag_entry, 0, sizeof(*sock_tag_entry));
-			sock_tag_entry->sk = el_socket->sk;
-			/* TODO: check that uid==current_fsuid() except
-			 * for special uid/gid. */
-			sock_tag_entry->tag = combine_atag_with_uid(acct_tag,
-								uid);
-			spin_lock_irqsave(&sock_tag_list_lock, flags);
-			sock_tag_tree_insert(sock_tag_entry, &sock_tag_tree);
-		} else {
-			/* HERE: The lock is held because there is a matching
-			 * sock tag entry */
-			/* Just update the acct_tag portion. */
-			uid_t orig_uid = get_uid_from_tag(sock_tag_entry->tag);
-			sock_tag_entry->tag = combine_atag_with_uid(acct_tag,
-								orig_uid);
-		}
-		spin_unlock_irqrestore(&sock_tag_list_lock, flags);
-		pr_debug("xt_qtaguid: tag: sock_tag_entry->sk=%p "
-			"...->tag=0x%llx (uid=%u)\n",
-			sock_tag_entry->sk, sock_tag_entry->tag,
-			get_uid_from_tag(sock_tag_entry->tag));
+		res = ctrl_cmd_tag(input);
 		break;
 
 	case 'u':
-		if (!sock_tag_entry) {
-			res = -EINVAL;
-			goto err;
-		}
-		/* TODO: check that the uid==current_fsuid()
-		 * except for special uid/gid. */
-		rb_erase(&sock_tag_entry->node, &sock_tag_tree);
-		spin_unlock_irqrestore(&sock_tag_list_lock, flags);
-		kfree(sock_tag_entry);
+		res = ctrl_cmd_untag(input);
 		break;
-	}
-
-	/* All of the input has been processed */
-	res = count;
-	goto ok;
 
-err_unlock:
-	if (sock_tag_entry)
-		spin_unlock_irqrestore(&sock_tag_list_lock, flags);
+	default:
+		res = -EINVAL;
+		goto err;
+	}
+	if (!res)
+		res = count;
 err:
-ok:
 	pr_debug("xt_qtaguid: ctrl(%s): res=%d\n", input, res);
 	return res;
 }
@@ -1099,6 +1223,57 @@ static int qtaguid_ctrl_proc_write(struct file *file, const char __user *buffer,
 	return qtaguid_ctrl_parse(input_buf, count);
 }
 
+static int print_stats_line(char *outp, int char_count, int item_index,
+			    char *ifname, tag_t tag,
+			    struct data_counters *counters)
+{
+	int len;
+	if (!item_index)
+		len = snprintf(outp, char_count,
+			 "idx iface acct_tag_hex uid_tag_int "
+			 "rx_bytes rx_packets "
+			 "tx_bytes tx_packets "
+			 "rx_tcp_packets rx_tcp_bytes "
+			 "rx_udp_packets rx_udp_bytes "
+			 "rx_other_packets rx_other_bytes "
+			 "tx_tcp_packets tx_tcp_bytes "
+			 "tx_udp_packets tx_udp_bytes "
+			 "tx_other_packets tx_other_bytes\n");
+	else
+		len = snprintf(outp, char_count,
+			       "%d %s 0x%llx %u "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu "
+			       "%llu %llu\n",
+			       item_index,
+			       ifname,
+			       get_atag_from_tag(tag),
+			       get_uid_from_tag(tag),
+			       dc_sum_bytes(counters, IFS_RX),
+			       dc_sum_packets(counters, IFS_RX),
+			       dc_sum_bytes(counters, IFS_TX),
+			       dc_sum_packets(counters, IFS_TX),
+			       counters->bpc[IFS_RX][IFS_TCP].bytes,
+			       counters->bpc[IFS_RX][IFS_TCP].packets,
+			       counters->bpc[IFS_RX][IFS_UDP].bytes,
+			       counters->bpc[IFS_RX][IFS_UDP].packets,
+			       counters->bpc[IFS_RX][IFS_PROTO_OTHER].bytes,
+			       counters->bpc[IFS_RX][IFS_PROTO_OTHER].packets,
+			       counters->bpc[IFS_TX][IFS_TCP].bytes,
+			       counters->bpc[IFS_TX][IFS_TCP].packets,
+			       counters->bpc[IFS_TX][IFS_UDP].bytes,
+			       counters->bpc[IFS_TX][IFS_UDP].packets,
+			       counters->bpc[IFS_TX][IFS_PROTO_OTHER].bytes,
+			       counters->bpc[IFS_TX][IFS_PROTO_OTHER].packets);
+	return len;
+}
+
+
 /*
  * Procfs reader to get all tag stats using style "1)" as described in
  * fs/proc/generic.c
@@ -1126,9 +1301,8 @@ static int qtaguid_stats_proc_read(char *page, char **num_items_returned,
 
 	if (!items_to_skip) {
 		/* The idx is there to help debug when things go belly up. */
-		len = snprintf(outp, char_count,
-			"idx iface acct_tag_hex uid_tag_int rx_bytes "
-			"tx_bytes\n");
+		len = print_stats_line(outp, char_count, /*index*/0, NULL,
+				       make_tag_from_uid(0), NULL);
 		/* Don't advance the outp unless the whole line was printed */
 		if (len >= char_count) {
 			*outp = '\0';
@@ -1137,7 +1311,6 @@ static int qtaguid_stats_proc_read(char *page, char **num_items_returned,
 		outp += len;
 		char_count -= len;
 	}
-
 	spin_lock_irqsave(&iface_stat_list_lock, flags);
 	list_for_each_entry(iface_entry, &iface_stat_list, list) {
 		struct rb_node *node;
@@ -1145,26 +1318,21 @@ static int qtaguid_stats_proc_read(char *page, char **num_items_returned,
 		for (node = rb_first(&iface_entry->tag_stat_tree);
 		     node;
 		     node = rb_next(node)) {
-			ts_entry =  rb_entry(node, struct tag_stat, node);
+			ts_entry = rb_entry(node, struct tag_stat, node);
 			if (item_index++ < items_to_skip)
 				continue;
-			len = snprintf(outp, char_count,
-				       "%d %s 0x%llx %u %llu %llu\n",
-				       item_index,
-				       iface_entry->ifname,
-				       get_atag_from_tag(ts_entry->tag),
-				       get_uid_from_tag(ts_entry->tag),
-				       dc_sum_bytes(&ts_entry->counters,
-						    IFS_RX),
-				       dc_sum_bytes(&ts_entry->counters,
-						    IFS_TX));
+			len = print_stats_line(outp, char_count,
+					       item_index,
+					       iface_entry->ifname,
+					       ts_entry->tag,
+					       &ts_entry->counters);
 			if (len >= char_count) {
+				*outp = '\0';
 				spin_unlock_irqrestore(
 					&iface_entry->tag_stat_list_lock,
 					flags2);
 				spin_unlock_irqrestore(
 					&iface_stat_list_lock, flags);
-				*outp = '\0';
 				return outp - page;
 			}
 			outp += len;