/* * 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. */intip_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 voidip_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 */intregister_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 voidvs_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");}