1 files changed, 617 insertions, 0 deletions

diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c
new file mode 100644
index 000000000..fdacbc3c1
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_app.c
@@ -0,0 +1,617 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ip_vs_app.c: Application module support for IPVS
+ *
+ * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
+ *
+ * Most code here is taken from ip_masq_app.c in kernel 2.2. The difference
+ * is that ip_vs_app module handles the reverse direction (incoming requests
+ * and outgoing responses).
+ *
+ *		IP_MASQ_APP application masquerading module
+ *
+ * Author:	Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar>
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/netfilter.h>
+#include <linux/slab.h>
+#include <net/net_namespace.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <linux/stat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/mutex.h>
+
+#include <net/ip_vs.h>
+
+EXPORT_SYMBOL(register_ip_vs_app);
+EXPORT_SYMBOL(unregister_ip_vs_app);
+EXPORT_SYMBOL(register_ip_vs_app_inc);
+
+static DEFINE_MUTEX(__ip_vs_app_mutex);
+
+/*
+ *	Get an ip_vs_app object
+ */
+static inline int ip_vs_app_get(struct ip_vs_app *app)
+{
+	return try_module_get(app->module);
+}
+
+
+static inline void ip_vs_app_put(struct ip_vs_app *app)
+{
+	module_put(app->module);
+}
+
+static void ip_vs_app_inc_destroy(struct ip_vs_app *inc)
+{
+	kfree(inc->timeout_table);
+	kfree(inc);
+}
+
+static void ip_vs_app_inc_rcu_free(struct rcu_head *head)
+{
+	struct ip_vs_app *inc = container_of(head, struct ip_vs_app, rcu_head);
+
+	ip_vs_app_inc_destroy(inc);
+}
+
+/*
+ *	Allocate/initialize app incarnation and register it in proto apps.
+ */
+static int
+ip_vs_app_inc_new(struct netns_ipvs *ipvs, struct ip_vs_app *app, __u16 proto,
+		  __u16 port)
+{
+	struct ip_vs_protocol *pp;
+	struct ip_vs_app *inc;
+	int ret;
+
+	if (!(pp = ip_vs_proto_get(proto)))
+		return -EPROTONOSUPPORT;
+
+	if (!pp->unregister_app)
+		return -EOPNOTSUPP;
+
+	inc = kmemdup(app, sizeof(*inc), GFP_KERNEL);
+	if (!inc)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&inc->p_list);
+	INIT_LIST_HEAD(&inc->incs_list);
+	inc->app = app;
+	inc->port = htons(port);
+	atomic_set(&inc->usecnt, 0);
+
+	if (app->timeouts) {
+		inc->timeout_table =
+			ip_vs_create_timeout_table(app->timeouts,
+						   app->timeouts_size);
+		if (!inc->timeout_table) {
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	ret = pp->register_app(ipvs, inc);
+	if (ret)
+		goto out;
+
+	list_add(&inc->a_list, &app->incs_list);
+	IP_VS_DBG(9, "%s App %s:%u registered\n",
+		  pp->name, inc->name, ntohs(inc->port));
+
+	return 0;
+
+  out:
+	ip_vs_app_inc_destroy(inc);
+	return ret;
+}
+
+
+/*
+ *	Release app incarnation
+ */
+static void
+ip_vs_app_inc_release(struct netns_ipvs *ipvs, struct ip_vs_app *inc)
+{
+	struct ip_vs_protocol *pp;
+
+	if (!(pp = ip_vs_proto_get(inc->protocol)))
+		return;
+
+	if (pp->unregister_app)
+		pp->unregister_app(ipvs, inc);
+
+	IP_VS_DBG(9, "%s App %s:%u unregistered\n",
+		  pp->name, inc->name, ntohs(inc->port));
+
+	list_del(&inc->a_list);
+
+	call_rcu(&inc->rcu_head, ip_vs_app_inc_rcu_free);
+}
+
+
+/*
+ *	Get reference to app inc (only called from softirq)
+ *
+ */
+int ip_vs_app_inc_get(struct ip_vs_app *inc)
+{
+	int result;
+
+	result = ip_vs_app_get(inc->app);
+	if (result)
+		atomic_inc(&inc->usecnt);
+	return result;
+}
+
+
+/*
+ *	Put the app inc (only called from timer or net softirq)
+ */
+void ip_vs_app_inc_put(struct ip_vs_app *inc)
+{
+	atomic_dec(&inc->usecnt);
+	ip_vs_app_put(inc->app);
+}
+
+
+/*
+ *	Register an application incarnation in protocol applications
+ */
+int
+register_ip_vs_app_inc(struct netns_ipvs *ipvs, struct ip_vs_app *app, __u16 proto,
+		       __u16 port)
+{
+	int result;
+
+	mutex_lock(&__ip_vs_app_mutex);
+
+	result = ip_vs_app_inc_new(ipvs, app, proto, port);
+
+	mutex_unlock(&__ip_vs_app_mutex);
+
+	return result;
+}
+
+
+/* Register application for netns */
+struct ip_vs_app *register_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app)
+{
+	struct ip_vs_app *a;
+	int err = 0;
+
+	mutex_lock(&__ip_vs_app_mutex);
+
+	/* increase the module use count */
+	if (!ip_vs_use_count_inc()) {
+		err = -ENOENT;
+		goto out_unlock;
+	}
+
+	list_for_each_entry(a, &ipvs->app_list, a_list) {
+		if (!strcmp(app->name, a->name)) {
+			err = -EEXIST;
+			/* decrease the module use count */
+			ip_vs_use_count_dec();
+			goto out_unlock;
+		}
+	}
+	a = kmemdup(app, sizeof(*app), GFP_KERNEL);
+	if (!a) {
+		err = -ENOMEM;
+		/* decrease the module use count */
+		ip_vs_use_count_dec();
+		goto out_unlock;
+	}
+	INIT_LIST_HEAD(&a->incs_list);
+	list_add(&a->a_list, &ipvs->app_list);
+
+out_unlock:
+	mutex_unlock(&__ip_vs_app_mutex);
+
+	return err ? ERR_PTR(err) : a;
+}
+
+
+/*
+ *	ip_vs_app unregistration routine
+ *	We are sure there are no app incarnations attached to services
+ *	Caller should use synchronize_rcu() or rcu_barrier()
+ */
+void unregister_ip_vs_app(struct netns_ipvs *ipvs, struct ip_vs_app *app)
+{
+	struct ip_vs_app *a, *anxt, *inc, *nxt;
+
+	mutex_lock(&__ip_vs_app_mutex);
+
+	list_for_each_entry_safe(a, anxt, &ipvs->app_list, a_list) {
+		if (app && strcmp(app->name, a->name))
+			continue;
+		list_for_each_entry_safe(inc, nxt, &a->incs_list, a_list) {
+			ip_vs_app_inc_release(ipvs, inc);
+		}
+
+		list_del(&a->a_list);
+		kfree(a);
+
+		/* decrease the module use count */
+		ip_vs_use_count_dec();
+	}
+
+	mutex_unlock(&__ip_vs_app_mutex);
+}
+
+
+/*
+ *	Bind ip_vs_conn to its ip_vs_app (called by cp constructor)
+ */
+int ip_vs_bind_app(struct ip_vs_conn *cp,
+		   struct ip_vs_protocol *pp)
+{
+	return pp->app_conn_bind(cp);
+}
+
+
+/*
+ *	Unbind cp from application incarnation (called by cp destructor)
+ */
+void ip_vs_unbind_app(struct ip_vs_conn *cp)
+{
+	struct ip_vs_app *inc = cp->app;
+
+	if (!inc)
+		return;
+
+	if (inc->unbind_conn)
+		inc->unbind_conn(inc, cp);
+	if (inc->done_conn)
+		inc->done_conn(inc, cp);
+	ip_vs_app_inc_put(inc);
+	cp->app = NULL;
+}
+
+
+/*
+ *	Fixes th->seq based on ip_vs_seq info.
+ */
+static inline void vs_fix_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
+{
+	__u32 seq = ntohl(th->seq);
+
+	/*
+	 *	Adjust seq with delta-offset for all packets after
+	 *	the most recent resized pkt seq and with previous_delta offset
+	 *	for all packets	before most recent resized pkt seq.
+	 */
+	if (vseq->delta || vseq->previous_delta) {
+		if(after(seq, vseq->init_seq)) {
+			th->seq = htonl(seq + vseq->delta);
+			IP_VS_DBG(9, "%s(): added delta (%d) to seq\n",
+				  __func__, vseq->delta);
+		} else {
+			th->seq = htonl(seq + vseq->previous_delta);
+			IP_VS_DBG(9, "%s(): added previous_delta (%d) to seq\n",
+				  __func__, vseq->previous_delta);
+		}
+	}
+}
+
+
+/*
+ *	Fixes th->ack_seq based on ip_vs_seq info.
+ */
+static inline void
+vs_fix_ack_seq(const struct ip_vs_seq *vseq, struct tcphdr *th)
+{
+	__u32 ack_seq = ntohl(th->ack_seq);
+
+	/*
+	 * Adjust ack_seq with delta-offset for
+	 * the packets AFTER most recent resized pkt has caused a shift
+	 * for packets before most recent resized pkt, use previous_delta
+	 */
+	if (vseq->delta || vseq->previous_delta) {
+		/* since ack_seq is the number of octet that is expected
+		   to receive next, so compare it with init_seq+delta */
+		if(after(ack_seq, vseq->init_seq+vseq->delta)) {
+			th->ack_seq = htonl(ack_seq - vseq->delta);
+			IP_VS_DBG(9, "%s(): subtracted delta "
+				  "(%d) from ack_seq\n", __func__, vseq->delta);
+
+		} else {
+			th->ack_seq = htonl(ack_seq - vseq->previous_delta);
+			IP_VS_DBG(9, "%s(): subtracted "
+				  "previous_delta (%d) from ack_seq\n",
+				  __func__, vseq->previous_delta);
+		}
+	}
+}
+
+
+/*
+ *	Updates ip_vs_seq if pkt has been resized
+ *	Assumes already checked proto==IPPROTO_TCP and diff!=0.
+ */
+static inline void vs_seq_update(struct ip_vs_conn *cp, struct ip_vs_seq *vseq,
+				 unsigned int flag, __u32 seq, int diff)
+{
+	/* spinlock is to keep updating cp->flags atomic */
+	spin_lock_bh(&cp->lock);
+	if (!(cp->flags & flag) || after(seq, vseq->init_seq)) {
+		vseq->previous_delta = vseq->delta;
+		vseq->delta += diff;
+		vseq->init_seq = seq;
+		cp->flags |= flag;
+	}
+	spin_unlock_bh(&cp->lock);
+}
+
+static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb,
+				  struct ip_vs_app *app,
+				  struct ip_vs_iphdr *ipvsh)
+{
+	int diff;
+	const unsigned int tcp_offset = ip_hdrlen(skb);
+	struct tcphdr *th;
+	__u32 seq;
+
+	if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
+		return 0;
+
+	th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
+
+	/*
+	 *	Remember seq number in case this pkt gets resized
+	 */
+	seq = ntohl(th->seq);
+
+	/*
+	 *	Fix seq stuff if flagged as so.
+	 */
+	if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
+		vs_fix_seq(&cp->out_seq, th);
+	if (cp->flags & IP_VS_CONN_F_IN_SEQ)
+		vs_fix_ack_seq(&cp->in_seq, th);
+
+	/*
+	 *	Call private output hook function
+	 */
+	if (app->pkt_out == NULL)
+		return 1;
+
+	if (!app->pkt_out(app, cp, skb, &diff, ipvsh))
+		return 0;
+
+	/*
+	 *	Update ip_vs seq stuff if len has changed.
+	 */
+	if (diff != 0)
+		vs_seq_update(cp, &cp->out_seq,
+			      IP_VS_CONN_F_OUT_SEQ, seq, diff);
+
+	return 1;
+}
+
+/*
+ *	Output pkt hook. Will call bound ip_vs_app specific function
+ *	called by ipvs packet handler, assumes previously checked cp!=NULL
+ *	returns false if it can't handle packet (oom)
+ */
+int ip_vs_app_pkt_out(struct ip_vs_conn *cp, struct sk_buff *skb,
+		      struct ip_vs_iphdr *ipvsh)
+{
+	struct ip_vs_app *app;
+
+	/*
+	 *	check if application module is bound to
+	 *	this ip_vs_conn.
+	 */
+	if ((app = cp->app) == NULL)
+		return 1;
+
+	/* TCP is complicated */
+	if (cp->protocol == IPPROTO_TCP)
+		return app_tcp_pkt_out(cp, skb, app, ipvsh);
+
+	/*
+	 *	Call private output hook function
+	 */
+	if (app->pkt_out == NULL)
+		return 1;
+
+	return app->pkt_out(app, cp, skb, NULL, ipvsh);
+}
+
+
+static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb,
+				 struct ip_vs_app *app,
+				 struct ip_vs_iphdr *ipvsh)
+{
+	int diff;
+	const unsigned int tcp_offset = ip_hdrlen(skb);
+	struct tcphdr *th;
+	__u32 seq;
+
+	if (skb_ensure_writable(skb, tcp_offset + sizeof(*th)))
+		return 0;
+
+	th = (struct tcphdr *)(skb_network_header(skb) + tcp_offset);
+
+	/*
+	 *	Remember seq number in case this pkt gets resized
+	 */
+	seq = ntohl(th->seq);
+
+	/*
+	 *	Fix seq stuff if flagged as so.
+	 */
+	if (cp->flags & IP_VS_CONN_F_IN_SEQ)
+		vs_fix_seq(&cp->in_seq, th);
+	if (cp->flags & IP_VS_CONN_F_OUT_SEQ)
+		vs_fix_ack_seq(&cp->out_seq, th);
+
+	/*
+	 *	Call private input hook function
+	 */
+	if (app->pkt_in == NULL)
+		return 1;
+
+	if (!app->pkt_in(app, cp, skb, &diff, ipvsh))
+		return 0;
+
+	/*
+	 *	Update ip_vs seq stuff if len has changed.
+	 */
+	if (diff != 0)
+		vs_seq_update(cp, &cp->in_seq,
+			      IP_VS_CONN_F_IN_SEQ, seq, diff);
+
+	return 1;
+}
+
+/*
+ *	Input pkt hook. Will call bound ip_vs_app specific function
+ *	called by ipvs packet handler, assumes previously checked cp!=NULL.
+ *	returns false if can't handle packet (oom).
+ */
+int ip_vs_app_pkt_in(struct ip_vs_conn *cp, struct sk_buff *skb,
+		     struct ip_vs_iphdr *ipvsh)
+{
+	struct ip_vs_app *app;
+
+	/*
+	 *	check if application module is bound to
+	 *	this ip_vs_conn.
+	 */
+	if ((app = cp->app) == NULL)
+		return 1;
+
+	/* TCP is complicated */
+	if (cp->protocol == IPPROTO_TCP)
+		return app_tcp_pkt_in(cp, skb, app, ipvsh);
+
+	/*
+	 *	Call private input hook function
+	 */
+	if (app->pkt_in == NULL)
+		return 1;
+
+	return app->pkt_in(app, cp, skb, NULL, ipvsh);
+}
+
+
+#ifdef CONFIG_PROC_FS
+/*
+ *	/proc/net/ip_vs_app entry function
+ */
+
+static struct ip_vs_app *ip_vs_app_idx(struct netns_ipvs *ipvs, loff_t pos)
+{
+	struct ip_vs_app *app, *inc;
+
+	list_for_each_entry(app, &ipvs->app_list, a_list) {
+		list_for_each_entry(inc, &app->incs_list, a_list) {
+			if (pos-- == 0)
+				return inc;
+		}
+	}
+	return NULL;
+
+}
+
+static void *ip_vs_app_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct net *net = seq_file_net(seq);
+	struct netns_ipvs *ipvs = net_ipvs(net);
+
+	mutex_lock(&__ip_vs_app_mutex);
+
+	return *pos ? ip_vs_app_idx(ipvs, *pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *ip_vs_app_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct ip_vs_app *inc, *app;
+	struct list_head *e;
+	struct net *net = seq_file_net(seq);
+	struct netns_ipvs *ipvs = net_ipvs(net);
+
+	++*pos;
+	if (v == SEQ_START_TOKEN)
+		return ip_vs_app_idx(ipvs, 0);
+
+	inc = v;
+	app = inc->app;
+
+	if ((e = inc->a_list.next) != &app->incs_list)
+		return list_entry(e, struct ip_vs_app, a_list);
+
+	/* go on to next application */
+	for (e = app->a_list.next; e != &ipvs->app_list; e = e->next) {
+		app = list_entry(e, struct ip_vs_app, a_list);
+		list_for_each_entry(inc, &app->incs_list, a_list) {
+			return inc;
+		}
+	}
+	return NULL;
+}
+
+static void ip_vs_app_seq_stop(struct seq_file *seq, void *v)
+{
+	mutex_unlock(&__ip_vs_app_mutex);
+}
+
+static int ip_vs_app_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_puts(seq, "prot port    usecnt name\n");
+	else {
+		const struct ip_vs_app *inc = v;
+
+		seq_printf(seq, "%-3s  %-7u %-6d %-17s\n",
+			   ip_vs_proto_name(inc->protocol),
+			   ntohs(inc->port),
+			   atomic_read(&inc->usecnt),
+			   inc->name);
+	}
+	return 0;
+}
+
+static const struct seq_operations ip_vs_app_seq_ops = {
+	.start = ip_vs_app_seq_start,
+	.next  = ip_vs_app_seq_next,
+	.stop  = ip_vs_app_seq_stop,
+	.show  = ip_vs_app_seq_show,
+};
+#endif
+
+int __net_init ip_vs_app_net_init(struct netns_ipvs *ipvs)
+{
+	INIT_LIST_HEAD(&ipvs->app_list);
+#ifdef CONFIG_PROC_FS
+	if (!proc_create_net("ip_vs_app", 0, ipvs->net->proc_net,
+			     &ip_vs_app_seq_ops,
+			     sizeof(struct seq_net_private)))
+		return -ENOMEM;
+#endif
+	return 0;
+}
+
+void __net_exit ip_vs_app_net_cleanup(struct netns_ipvs *ipvs)
+{
+	unregister_ip_vs_app(ipvs, NULL /* all */);
+#ifdef CONFIG_PROC_FS
+	remove_proc_entry("ip_vs_app", ipvs->net->proc_net);
+#endif
+}