ipv6addr.c

在LINUX下实现HA的源代码

/*
 * This program manages IPv6 address.
 *
 * Author: Huang Zhen <[e-mail]>
 * Copyright (c) 2004 International Business Machines
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
 
/*
 * It can add an IPv6 address, or remove one.
 *
 * Usage:  IPv6addr ipv6-address {start|stop|status|monitor}
 *
 * The "start" arg adds an IPv6 address.
 * The "stop" arg removes one.
 * The "status" arg shows whether the IPv6 address exists
 * The "monitor" arg shows whether the IPv6 address can be pinged (ICMPv6 ECHO)
 */
 
/*
 * ipv6-address:
 *
 * currently the following forms are legal:
 *	address
 *	address/prefix
 *
 *     E.g.
 *	3ffe:ffff:0:f101::1
 *	3ffe:ffff:0:f101::1/64
 *
 */
 
/*
 * start:
 * 	1.IPv6addr will choice a proper interface for the new address.
 *	2.Then assign the new address to the interface.
 *	3.Wait until the new address is available (reply ICMPv6 ECHO packet)
 *	4.Send out the unsolicited advertisements.
 *
 *	return 0(LSB_EXIT_OK) for success
 *	return 1(LSB_EXIT_GENERIC) for failure
 *
 *
 * stop:
 *	remove the address from the inferface.
 *
 *	return 0(LSB_EXIT_OK) for success
 *	return 1(LSB_EXIT_GENERIC) for failure
 *
 * status:
 *	return the status of the address. only check whether it exists.
 *
 *	return 0(LSB_STATUS_OK) for existing
 *	return 1(LSB_STATUS_STOPPED) for not existing
 *
 *
 * monitor:
 *	ping the address by ICMPv6 ECHO request.
 *
 *	return 0(LSB_STATUS_OK) for response correctly.
 *	return 1(LSB_STATUS_STOPPED) for no response.
 *
 */
 
#include <config.h>
#include <asm/types.h>
#include <libgen.h>
#include <syslog.h>
#include <clplumbing/cl_log.h>
#include <libnet.h>
#include <linux/icmpv6.h>
#include <clplumbing/lsb_exitcodes.h>

#if defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ < 2
#	include <sys/uio.h>
#endif 


#define PIDDIR HA_VARRUNDIR
#define PIDFILE_BASE PIDDIR "/IPv6addr-"



const char* IF_INET6	 	= "/proc/net/if_inet6";
const char* APP_NAME		= "IPv6addr";

const char*	START_CMD 	= "start";
const char*	STOP_CMD  	= "stop";
const char*	STATUS_CMD 	= "status";
const char*	MONITOR_CMD 	= "monitor";
const char*	ADVT_CMD	= "advt";
char		BCAST_ADDR[]	= "ff02::1";
const int	UA_REPEAT_COUNT	= 5;
const int	QUERY_COUNT	= 5;

struct in6_ifreq {
    struct in6_addr ifr6_addr;
    __u32 ifr6_prefixlen;
    unsigned int ifr6_ifindex;
};

static int start_addr6(struct in6_addr* addr6, int prefix_len);
static int stop_addr6(struct in6_addr* addr6, int prefix_len);
static int status_addr6(struct in6_addr* addr6, int prefix_len);
static int monitor_addr6(struct in6_addr* addr6, int prefix_len);
static int advt_addr6(struct in6_addr* addr6, int prefix_len);


static void usage(const char* self);
int write_pid_file(const char *pid_file);
int create_pid_directory(const char *pid_file);
static void byebye(int nsig);

static char* find_if(struct in6_addr* addr_target, int* plen_target);
static char* get_if(struct in6_addr* addr_target, int* plen_target);
static int assign_addr6(struct in6_addr* addr6, int prefix_len, char* if_name);
static int unassign_addr6(struct in6_addr* addr6, int prefix_len, char* if_name);
int is_addr6_available(struct in6_addr* addr6);
static int send_ua(struct in6_addr* src_ip, char* if_name);

int
main(int argc, char* argv[])
{
	char		pid_file[256];
	int		ret;
	char*		cp;
	int		prefix_len;
	struct in6_addr	addr6;

	/* Check the count of parameters first */
	if (argc < 3) {
		usage(argv[0]);
		return EXIT_FAILURE;
	}

	/* set termination signal */
	siginterrupt(SIGTERM, 1);
	signal(SIGTERM, byebye);

	/* open system log */
	openlog(APP_NAME, LOG_CONS | LOG_PID, LOG_USER);

	/* check the first parameter, should be a IPv6 address */
	if ((cp = strchr(argv[1], '/'))) {
		prefix_len = atol(cp + 1);
		if ((prefix_len < 0) || (prefix_len > 128)) {
			usage(argv[0]);
			return EXIT_FAILURE;
		} 
		*cp=0;
	} else {
		prefix_len = 0;
	}
	
	if (inet_pton(AF_INET6, argv[1], &addr6) <= 0) {
		usage(argv[0]);
		return EXIT_FAILURE;
	}
	
	/* Check whether this system supports IPv6 */
	if (access(IF_INET6, R_OK)) {
		cl_log(LOG_ERR, "No support for INET6 on this system.");
		return EXIT_FAILURE;
	}
	
	/* create the pid file so we can make sure that only one IPv6addr
	 * for this address is running
	 */
	if (snprintf(pid_file, sizeof(pid_file), "%s%s", PIDFILE_BASE, argv[1])
		>= (int)sizeof(pid_file)) {
		cl_log(LOG_ERR, "Pid file truncated");
		return EXIT_FAILURE;
	}

	if (write_pid_file(pid_file) < 0) {
		return EXIT_FAILURE;
	}


	/* switch the command */
	if (0 == strncmp(START_CMD,argv[2], strlen(START_CMD))) {
		ret = start_addr6(&addr6, prefix_len);
	}else if (0 == strncmp(STOP_CMD,argv[2], strlen(STOP_CMD))) {
		ret = stop_addr6(&addr6, prefix_len);
	}else if (0 == strncmp(STATUS_CMD,argv[2], strlen(STATUS_CMD))) {
		ret = status_addr6(&addr6, prefix_len);
	}else if (0 ==strncmp(MONITOR_CMD,argv[2], strlen(MONITOR_CMD))) {
		ret = monitor_addr6(&addr6, prefix_len);
	}else if (0 ==strncmp(ADVT_CMD,argv[2], strlen(MONITOR_CMD))) {
		ret = advt_addr6(&addr6, prefix_len);
	}else{
		usage(argv[0]);
		ret = EXIT_FAILURE;
	}
	
	/* release the pid file */
	unlink(pid_file);

	return ret;
}
int
start_addr6(struct in6_addr* addr6, int prefix_len)
{
	/* First, we need to find a proper device to assign the address */
	int	i;
	char*	if_name = find_if(addr6, &prefix_len);
	if (NULL == if_name) {
		cl_log(LOG_ERR, "no valid mecahnisms");
		return LSB_EXIT_GENERIC;
	}

	/* Assign the address */
	if (0 != assign_addr6(addr6, prefix_len, if_name)) {
		cl_log(LOG_ERR, "failed to assign the address to %s", if_name);
		return LSB_EXIT_GENERIC;
	}

	/* Check whether the address available */
	for (i = 0; i < QUERY_COUNT; i++) {
		if (0 == is_addr6_available(addr6)) {
			break;
		}
		sleep(1);
	}
	if (i == QUERY_COUNT) {
		cl_log(LOG_ERR, "failed to ping the address");
		return LSB_EXIT_GENERIC;
	}
	
	/* Send unsolicited advertisement packet to neighbor */
	for (i = 0; i < UA_REPEAT_COUNT; i++) {
		send_ua(addr6, if_name);
		sleep(1);
	}
	return LSB_EXIT_OK;
}

int
advt_addr6(struct in6_addr* addr6, int prefix_len)
{
	/* First, we need to find a proper device to assign the address */
	char*	if_name = get_if(addr6, &prefix_len);
	int	i;
	if (NULL == if_name) {
		cl_log(LOG_ERR, "no valid mecahnisms");
		return LSB_EXIT_GENERIC;
	}
	/* Send unsolicited advertisement packet to neighbor */
	for (i = 0; i < UA_REPEAT_COUNT; i++) {
		send_ua(addr6, if_name);
		sleep(1);
	}
	return LSB_STATUS_OK;
}
	
int
stop_addr6(struct in6_addr* addr6, int prefix_len)
{
	char* if_name = get_if(addr6, &prefix_len);

	if (NULL == if_name) {
		cl_log(LOG_ERR, "no valid mechanisms.");
		/* I think this should be a success exit according to LSB. */
		return LSB_EXIT_GENERIC;
	}

	/* Unassign the address */
	if (0 != unassign_addr6(addr6, prefix_len, if_name)) {
		cl_log(LOG_ERR, "failed to assign the address to %s", if_name);
		return LSB_EXIT_GENERIC;
	}

	return LSB_EXIT_OK;
}

int
status_addr6(struct in6_addr* addr6, int prefix_len)
{
	char* if_name = get_if(addr6, &prefix_len);
	if (NULL == if_name) {
		return LSB_STATUS_STOPPED;
	}
	return LSB_STATUS_OK;
}
	
int
monitor_addr6(struct in6_addr* addr6, int prefix_len)
{
	if(0 == is_addr6_available(addr6)) {
		return LSB_STATUS_OK;
	}
	return LSB_STATUS_STOPPED;

}

/* Send an unsolicited advertisement packet
 * Please refer to rfc2461
 */
int
send_ua(struct in6_addr* src_ip, char* if_name)
{
	libnet_t *l;
	char errbuf[LIBNET_ERRBUF_SIZE];

	struct libnet_in6_addr dst_ip;
	struct libnet_ether_addr *mac_address;
	char payload[24];


	if ((l=libnet_init(LIBNET_RAW6, if_name, errbuf)) == NULL) {
		cl_log(LOG_ERR, "libnet_init failure on %s", if_name);
		return -1;
	}

	mac_address = libnet_get_hwaddr(l);
	if (!mac_address) {
		cl_log(LOG_ERR, "libnet_get_hwaddr: %s", errbuf);
		return -1;
	}

	dst_ip = libnet_name2addr6(l, BCAST_ADDR, LIBNET_DONT_RESOLVE);

	memcpy(payload,src_ip->s6_addr,16);
	payload[16] = 2; /* 2 for Target Link-layer Address */
	payload[17] = 1; /* The length of the option */
	memcpy(payload+18,mac_address->ether_addr_octet, 6);

	libnet_seed_prand(l);
	/* 0x2000: RSO */
	libnet_build_icmpv4_echo(136,0,0,0x2000,0,(unsigned char*)payload,sizeof(payload),
				 l,LIBNET_PTAG_INITIALIZER);
	libnet_build_ipv6(0,0,LIBNET_ICMPV6_H + sizeof(payload),IPPROTO_ICMP6,
				255,*(struct libnet_in6_addr*)src_ip,
				dst_ip,NULL,0,l,0);

        if (libnet_write(l) == -1)
        {
		cl_log(LOG_ERR, "libnet_write: %s", libnet_geterror(l));
		return -1;
	}

	return 0;
}

/* find a proper network interface to assign the address */
char*
find_if(struct in6_addr* addr_target, int* plen_target)
{
	FILE *f;
	char addr6[40];
	static char devname[20]="";
	struct in6_addr addr;
	struct in6_addr mask;
	int		plen;
	int		scope;
	int		dad_status;
	int		if_idx;
	char addr6p[8][5];

	/* open /proc/net/if_inet6 file */
	if ((f = fopen(IF_INET6, "r")) == NULL) {
		return NULL;
	}

	/* Loop for each entry */
	while ( fscanf(f,"%4s%4s%4s%4s%4s%4s%4s%4s %02x %02x %02x %02x %20s\n",
			addr6p[0], addr6p[1], addr6p[2], addr6p[3],
			addr6p[4], addr6p[5], addr6p[6], addr6p[7],
			&if_idx, &plen, &scope, &dad_status, devname) != EOF){

		int		i;
		int		n;
		int		s;
		gboolean	same = TRUE;

		sprintf(addr6, "%s:%s:%s:%s:%s:%s:%s:%s",
			addr6p[0], addr6p[1], addr6p[2], addr6p[3],
			addr6p[4], addr6p[5], addr6p[6], addr6p[7]);