1 files changed, 658 insertions, 0 deletions

diff --git a/net/ipv4/ipvs/ip_vs_app.c b/net/ipv4/ipvs/ip_vs_app.c
new file mode 100644
index 000000000000..d9212addd193
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_app.c
@@ -0,0 +1,658 @@
+/*
+ * ip_vs_app.c: Application module support for IPVS
+ *
+ * Version:     $Id: ip_vs_app.c,v 1.17 2003/03/22 06:31:21 wensong Exp $
+ *
+ * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ * 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>
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <net/protocol.h>
+#include <asm/system.h>
+#include <linux/stat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.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);
+
+/* ipvs application list head */
+static LIST_HEAD(ip_vs_app_list);
+static DECLARE_MUTEX(__ip_vs_app_mutex);
+
+
+/*
+ *	Get an ip_vs_app object
+ */
+static inline int ip_vs_app_get(struct ip_vs_app *app)
+{
+	/* test and get the module atomically */
+	if (app->module)
+		return try_module_get(app->module);
+	else
+		return 1;
+}
+
+
+static inline void ip_vs_app_put(struct ip_vs_app *app)
+{
+	if (app->module)
+		module_put(app->module);
+}
+
+
+/*
+ *	Allocate/initialize app incarnation and register it in proto apps.
+ */
+static int
+ip_vs_app_inc_new(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 = kmalloc(sizeof(struct ip_vs_app), GFP_KERNEL);
+	if (!inc)
+		return -ENOMEM;
+	memcpy(inc, app, sizeof(*inc));
+	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(inc);
+	if (ret)
+		goto out;
+
+	list_add(&inc->a_list, &app->incs_list);
+	IP_VS_DBG(9, "%s application %s:%u registered\n",
+		  pp->name, inc->name, inc->port);
+
+	return 0;
+
+  out:
+	if (inc->timeout_table)
+		kfree(inc->timeout_table);
+	kfree(inc);
+	return ret;
+}
+
+
+/*
+ *	Release app incarnation
+ */
+static void
+ip_vs_app_inc_release(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(inc);
+
+	IP_VS_DBG(9, "%s App %s:%u unregistered\n",
+		  pp->name, inc->name, inc->port);
+
+	list_del(&inc->a_list);
+
+	if (inc->timeout_table != NULL)
+		kfree(inc->timeout_table);
+	kfree(inc);
+}
+
+
+/*
+ *	Get reference to app inc (only called from softirq)
+ *
+ */
+int ip_vs_app_inc_get(struct ip_vs_app *inc)
+{
+	int result;
+
+	atomic_inc(&inc->usecnt);
+	if (unlikely((result = ip_vs_app_get(inc->app)) != 1))
+		atomic_dec(&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)
+{
+	ip_vs_app_put(inc->app);
+	atomic_dec(&inc->usecnt);
+}
+
+
+/*
+ *	Register an application incarnation in protocol applications
+ */
+int
+register_ip_vs_app_inc(struct ip_vs_app *app, __u16 proto, __u16 port)
+{
+	int result;
+
+	down(&__ip_vs_app_mutex);
+
+	result = ip_vs_app_inc_new(app, proto, port);
+
+	up(&__ip_vs_app_mutex);
+
+	return result;
+}
+
+
+/*
+ *	ip_vs_app registration routine
+ */
+int register_ip_vs_app(struct ip_vs_app *app)
+{
+	/* increase the module use count */
+	ip_vs_use_count_inc();
+
+	down(&__ip_vs_app_mutex);
+
+	list_add(&app->a_list, &ip_vs_app_list);
+
+	up(&__ip_vs_app_mutex);
+
+	return 0;
+}
+
+
+/*
+ *	ip_vs_app unregistration routine
+ *	We are sure there are no app incarnations attached to services
+ */
+void unregister_ip_vs_app(struct ip_vs_app *app)
+{
+	struct ip_vs_app *inc, *nxt;
+
+	down(&__ip_vs_app_mutex);
+
+	list_for_each_entry_safe(inc, nxt, &app->incs_list, a_list) {
+		ip_vs_app_inc_release(inc);
+	}
+
+	list_del(&app->a_list);
+
+	up(&__ip_vs_app_mutex);
+
+	/* decrease the module use count */
+	ip_vs_use_count_dec();
+}
+
+
+#if 0000
+/*
+ *	Get reference to app by name (called from user context)
+ */
+struct ip_vs_app *ip_vs_app_get_by_name(char *appname)
+{
+	struct ip_vs_app *app, *a = NULL;
+
+	down(&__ip_vs_app_mutex);
+
+	list_for_each_entry(ent, &ip_vs_app_list, a_list) {
+		if (strcmp(app->name, appname))
+			continue;
+
+		/* softirq may call ip_vs_app_get too, so the caller
+		   must disable softirq on the current CPU */
+		if (ip_vs_app_get(app))
+			a = app;
+		break;
+	}
+
+	up(&__ip_vs_app_mutex);
+
+	return a;
+}
+#endif
+
+
+/*
+ *	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, "vs_fix_seq(): added delta (%d) to seq\n",
+				  vseq->delta);
+		} else {
+			th->seq = htonl(seq + vseq->previous_delta);
+			IP_VS_DBG(9, "vs_fix_seq(): added previous_delta "
+				  "(%d) to seq\n", 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, "vs_fix_ack_seq(): subtracted delta "
+				  "(%d) from ack_seq\n", vseq->delta);
+
+		} else {
+			th->ack_seq = htonl(ack_seq - vseq->previous_delta);
+			IP_VS_DBG(9, "vs_fix_ack_seq(): subtracted "
+				  "previous_delta (%d) from ack_seq\n",
+				  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 flag, __u32 seq, int diff)
+{
+	/* spinlock is to keep updating cp->flags atomic */
+	spin_lock(&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(&cp->lock);
+}
+
+static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb,
+				  struct ip_vs_app *app)
+{
+	int diff;
+	unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4;
+	struct tcphdr *th;
+	__u32 seq;
+
+	if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
+		return 0;
+
+	th = (struct tcphdr *)((*pskb)->nh.raw + 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, pskb, &diff))
+		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 **pskb)
+{
+	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, pskb, app);
+
+	/*
+	 *	Call private output hook function
+	 */
+	if (app->pkt_out == NULL)
+		return 1;
+
+	return app->pkt_out(app, cp, pskb, NULL);
+}
+
+
+static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb,
+				 struct ip_vs_app *app)
+{
+	int diff;
+	unsigned int tcp_offset = (*pskb)->nh.iph->ihl*4;
+	struct tcphdr *th;
+	__u32 seq;
+
+	if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
+		return 0;
+
+	th = (struct tcphdr *)((*pskb)->nh.raw + 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, pskb, &diff))
+		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 **pskb)
+{
+	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, pskb, app);
+
+	/*
+	 *	Call private input hook function
+	 */
+	if (app->pkt_in == NULL)
+		return 1;
+
+	return app->pkt_in(app, cp, pskb, NULL);
+}
+
+
+#ifdef CONFIG_PROC_FS
+/*
+ *	/proc/net/ip_vs_app entry function
+ */
+
+static struct ip_vs_app *ip_vs_app_idx(loff_t pos)
+{
+	struct ip_vs_app *app, *inc;
+
+	list_for_each_entry(app, &ip_vs_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)
+{
+	down(&__ip_vs_app_mutex);
+
+	return *pos ? ip_vs_app_idx(*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;
+
+	++*pos;
+	if (v == SEQ_START_TOKEN)
+		return ip_vs_app_idx(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 != &ip_vs_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)
+{
+	up(&__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 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,
+};
+
+static int ip_vs_app_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &ip_vs_app_seq_ops);
+}
+
+static struct file_operations ip_vs_app_fops = {
+	.owner	 = THIS_MODULE,
+	.open	 = ip_vs_app_open,
+	.read	 = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+#endif
+
+
+/*
+ *	Replace a segment of data with a new segment
+ */
+int ip_vs_skb_replace(struct sk_buff *skb, int pri,
+		      char *o_buf, int o_len, char *n_buf, int n_len)
+{
+	struct iphdr *iph;
+	int diff;
+	int o_offset;
+	int o_left;
+
+	EnterFunction(9);
+
+	diff = n_len - o_len;
+	o_offset = o_buf - (char *)skb->data;
+	/* The length of left data after o_buf+o_len in the skb data */
+	o_left = skb->len - (o_offset + o_len);
+
+	if (diff <= 0) {
+		memmove(o_buf + n_len, o_buf + o_len, o_left);
+		memcpy(o_buf, n_buf, n_len);
+		skb_trim(skb, skb->len + diff);
+	} else if (diff <= skb_tailroom(skb)) {
+		skb_put(skb, diff);
+		memmove(o_buf + n_len, o_buf + o_len, o_left);
+		memcpy(o_buf, n_buf, n_len);
+	} else {
+		if (pskb_expand_head(skb, skb_headroom(skb), diff, pri))
+			return -ENOMEM;
+		skb_put(skb, diff);
+		memmove(skb->data + o_offset + n_len,
+			skb->data + o_offset + o_len, o_left);
+		memcpy(skb->data + o_offset, n_buf, n_len);
+	}
+
+	/* must update the iph total length here */
+	iph = skb->nh.iph;
+	iph->tot_len = htons(skb->len);
+
+	LeaveFunction(9);
+	return 0;
+}
+
+
+int ip_vs_app_init(void)
+{
+	/* we will replace it with proc_net_ipvs_create() soon */
+	proc_net_fops_create("ip_vs_app", 0, &ip_vs_app_fops);
+	return 0;
+}
+
+
+void ip_vs_app_cleanup(void)
+{
+	proc_net_remove("ip_vs_app");
+}