ip_vs_proto_icmp.c

h内核

/*
 * ip_vs_proto_icmp.c:	ICMP load balancing support for IP Virtual Server
 *
 * Authors:	Julian Anastasov <[e-mail]>, March 2002
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		version 2 as published by the Free Software Foundation;
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/icmp.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>

#include <net/ip_vs.h>


static int icmp_timeouts[1] =		{ 1*60*HZ };

static char * icmp_state_name_table[1] = { "ICMP" };

static struct ip_vs_conn *
icmp_conn_in_get(const struct sk_buff *skb,
		 struct ip_vs_protocol *pp,
		 const struct iphdr *iph,
		 unsigned int proto_off,
		 int inverse)
{
#if 0
	struct ip_vs_conn *cp;

	if (likely(!inverse)) {
		cp = ip_vs_conn_in_get(iph->protocol,
			iph->saddr, 0,
			iph->daddr, 0);
	} else {
		cp = ip_vs_conn_in_get(iph->protocol,
			iph->daddr, 0,
			iph->saddr, 0);
	}

	return cp;

#else
	return NULL;
#endif
}

static struct ip_vs_conn *
icmp_conn_out_get(const struct sk_buff *skb,
		  struct ip_vs_protocol *pp,
		  const struct iphdr *iph,
		  unsigned int proto_off,
		  int inverse)
{
#if 0
	struct ip_vs_conn *cp;

	if (likely(!inverse)) {
		cp = ip_vs_conn_out_get(iph->protocol,
			iph->saddr, 0,
			iph->daddr, 0);
	} else {
		cp = ip_vs_conn_out_get(IPPROTO_UDP,
			iph->daddr, 0,
			iph->saddr, 0);
	}

	return cp;
#else
	return NULL;
#endif
}

static int
icmp_conn_schedule(struct sk_buff *skb, struct ip_vs_protocol *pp,
		   int *verdict, struct ip_vs_conn **cpp)
{
	*verdict = NF_ACCEPT;
	return 0;
}

static int
icmp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
{
	if (!(skb->nh.iph->frag_off & __constant_htons(IP_OFFSET))) {
		if (skb->ip_summed != CHECKSUM_UNNECESSARY) {
			if (ip_vs_checksum_complete(skb, skb->nh.iph->ihl * 4)) {
				IP_VS_DBG_RL_PKT(0, pp, skb, 0, "Failed checksum for");
				return 0;
			}
		}
	}
	return 1;
}

static void
icmp_debug_packet(struct ip_vs_protocol *pp,
		  const struct sk_buff *skb,
		  int offset,
		  const char *msg)
{
	char buf[256];
	struct iphdr _iph, *ih;

	ih = skb_header_pointer(skb, offset, sizeof(_iph), &_iph);
	if (ih == NULL)
		sprintf(buf, "%s TRUNCATED", pp->name);
	else if (ih->frag_off & __constant_htons(IP_OFFSET))
		sprintf(buf, "%s %u.%u.%u.%u->%u.%u.%u.%u frag",
			pp->name, NIPQUAD(ih->saddr),
			NIPQUAD(ih->daddr));
	else {
		struct icmphdr _icmph, *ic;

		ic = skb_header_pointer(skb, offset + ih->ihl*4,
					sizeof(_icmph), &_icmph);
		if (ic == NULL)
			sprintf(buf, "%s TRUNCATED to %u bytes\n",
				pp->name, skb->len - offset);
		else
			sprintf(buf, "%s %u.%u.%u.%u->%u.%u.%u.%u T:%d C:%d",
				pp->name, NIPQUAD(ih->saddr),
				NIPQUAD(ih->daddr),
				ic->type, ic->code);
	}
	printk(KERN_DEBUG "IPVS: %s: %s\n", msg, buf);
}

static int
icmp_state_transition(struct ip_vs_conn *cp, int direction,
		      const struct sk_buff *skb,
		      struct ip_vs_protocol *pp)
{
	cp->timeout = pp->timeout_table[IP_VS_ICMP_S_NORMAL];
	return 1;
}

static int
icmp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
{
	int num;
	char **names;

	num = IP_VS_ICMP_S_LAST;
	names = icmp_state_name_table;
	return ip_vs_set_state_timeout(pp->timeout_table, num, names, sname, to);
}


static void icmp_init(struct ip_vs_protocol *pp)
{
	pp->timeout_table = icmp_timeouts;
}

static void icmp_exit(struct ip_vs_protocol *pp)
{
}

struct ip_vs_protocol ip_vs_protocol_icmp = {
	.name =			"ICMP",
	.protocol =		IPPROTO_ICMP,
	.dont_defrag =		0,
	.init =			icmp_init,
	.exit =			icmp_exit,
	.conn_schedule =	icmp_conn_schedule,
	.conn_in_get =		icmp_conn_in_get,
	.conn_out_get =		icmp_conn_out_get,
	.snat_handler =		NULL,
	.dnat_handler =		NULL,
	.csum_check =		icmp_csum_check,
	.state_transition =	icmp_state_transition,
	.register_app =		NULL,
	.unregister_app =	NULL,
	.app_conn_bind =	NULL,
	.debug_packet =		icmp_debug_packet,
	.timeout_change =	NULL,
	.set_state_timeout =	icmp_set_state_timeout,
};