/*
	Create/manage IP aliases maping long name to short name to please
	the limitation of the kernel. The short names all start with V.
	The program use the file /var/run/vipaliases to store the name.
	The name at line 5 correspond to V5 and so on.

	vipalias set name ip netmask broadcast
	vipalias unset name
	vipalias list
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>

#include <vector>
#include <map>
#include <string>

using namespace std;

static const char *statefile = "/var/run/vipaliases";
static const char *lockfile = "/var/run/vipaliases.lock";

static void usage()
{
	fprintf (stderr,"vipalias version %s\n",VERSION);
	fprintf (stderr,
		"\n"
		"vipalias set device name ip netmask broadcast\n"
		"vipalias unset device name\n"
		"vipalias list\n");
}

#include "vipalias.lock.h"

static int vipalias_find (vector<string> &tb, const char *name)
{
	int ret = -1;
	for (vector<string>::iterator it = tb.begin();
		it != tb.end(); it++){
		if (strcmp(it->c_str(),name)==0){
			ret = it - tb.begin();
			break;
		}
	}
	return ret;
}

static void vipalias_read (vector<string> &tb)
{
	FILE *fin = fopen (statefile,"r");
	if (fin != NULL){
		char line[1000];
		while (fgets(line,sizeof(line)-1,fin)!=NULL){
			char *pt = strchr(line,'\n');
			if (pt != NULL) *pt = '\0';
			if (line[0] > ' '){
				tb.push_back(line);
			}
		}
		fclose (fin);
	}
}

static void vipalias_write (vector<string> &tb)
{
	FILE *fout = fopen (statefile,"w");
	if (fout != NULL){
		for (vector<string>::iterator it = tb.begin();
			it != tb.end(); it++){
			fprintf (fout,"%s\n",it->c_str());
		}
		fclose (fout);
	}
}

static void ipnum_ip2a(unsigned long ip, char *buf)
{
	sprintf (buf,"%u.%u.%u.%u"
		,(unsigned)(ip >> 24)
		,(unsigned)((ip >> 16 ) & 0xff)
		,(unsigned)((ip >> 8 ) & 0xff)
		,(unsigned)(ip & 0xff));
}

static int ifconfig_ioctl(
	int fd,
	const char *ifname,
	int cmd,
	struct ifreq &ifr)
{
	strcpy(ifr.ifr_name, ifname);
	return ioctl(fd, cmd,&ifr);
}

static void ifconfig_format (struct sockaddr &adr, char *buf)
{
	struct sockaddr_in *sin = (struct sockaddr_in*)&adr;
	ipnum_ip2a (htonl(sin->sin_addr.s_addr),buf);
}


static int ifconfig_getinfo (
	const char *ifname,
	char ip[20],
	char mask[20],
	char bcast[20])
{
	int ret = -1;
	strcpy (ip,"0.0.0.0");
	strcpy (mask,"0.0.0.0");
	strcpy (bcast,"0.0.0.0");
	int skfd = socket(AF_INET, SOCK_DGRAM, 0);
	if (skfd != -1){
		struct ifreq ifr;
		if (ifconfig_ioctl(skfd, ifname, SIOCGIFFLAGS, ifr) >= 0){
			ret = 0;
			if (ifconfig_ioctl(skfd,ifname,SIOCGIFADDR, ifr) >= 0){
				ifconfig_format (ifr.ifr_addr,ip);
				if (ifconfig_ioctl(skfd, ifname,SIOCGIFNETMASK, ifr) >= 0) {
					ifconfig_format (ifr.ifr_netmask,mask);
					if (ifconfig_ioctl(skfd, ifname,SIOCGIFBRDADDR, ifr) >= 0) {
						ifconfig_format (ifr.ifr_broadaddr,bcast);
					}
				}
			}
		}
		close (skfd);
	}
	return ret;
}

/*
	Read all the aliases, find the DEV:Vnn ones, and map nn to DEV
*/
static void devlist_read(
	map<int,string> &v2dev)
{
	int ret = -1;
	int skfd = socket (AF_INET,SOCK_DGRAM,0);
	if (skfd < 0) {
		perror ("socket");
	}else{
		struct ifconf ifc;
		int numreqs = 30;
		ifc.ifc_buf = NULL;
		ret = 0;
		while (1) {
			ifc.ifc_len = sizeof(struct ifreq) * numreqs;
			ifc.ifc_buf = (char*)realloc(ifc.ifc_buf, ifc.ifc_len);

			if (ioctl(skfd, SIOCGIFCONF, &ifc) < 0) {
				perror("SIOCGIFCONF");
				ret = -1;
				break;
			}
			if (ifc.ifc_len == (int)sizeof(struct ifreq) * numreqs) {
				/* assume it overflowed and try again */
				numreqs += 10;
				continue;
			}
			break;
		}
		if (ret == 0){
			struct ifreq *ifr = ifc.ifc_req;
			for (int n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
				const char *name = ifr->ifr_name;
				const char *pt = strchr(name,':');
				if (pt != NULL && pt[1] == 'V' && isdigit(pt[2])){
					int pos = atoi(pt+2);
					string dev(name,pt);
					v2dev[pos] = dev;
				}
				ifr++;
			}
		}
		free(ifc.ifc_buf);
	}
}


int main (int argc, char *argv[])
{
	int ret = -1;
	vector<string> tb;
	if (argc == 7 && strcmp(argv[1],"set")==0){
		const char *device = argv[2];
		const char *name = argv[3];
		const char *ip = argv[4];
		const char *mask = argv[5];
		const char *bcast = argv[6];
		if (vipalias_lock() != -1){
			vipalias_read(tb);
			int pos = vipalias_find (tb,name);
			if (pos == -1){
				pos = vipalias_find(tb,"-");
				if (pos != -1){
					tb[pos] = name;
				}else{
					pos = tb.size();
					tb.push_back(name);
				}
				vipalias_write (tb);
			}
			
			char tmp[200];
			snprintf (tmp,sizeof(tmp)-1
					,"/sbin/ifconfig %s:V%d %s netmask %s broadcast %s"
					,device,pos,ip,mask,bcast);
			ret = system(tmp);
			vipalias_unlock();
		}
	}else if (argc == 4 && strcmp(argv[1],"unset")==0){
		const char *device = argv[2];
		const char *name = argv[3];
		if (vipalias_lock() != -1){
			vipalias_read(tb);
			int pos = vipalias_find (tb,name);
			if (pos != -1){
				tb[pos] = "-";
				char tmp[100];
				snprintf (tmp,sizeof(tmp)-1,"/sbin/ifconfig %s:V%d down"
					,device,pos);
				ret = system(tmp);
				vipalias_write (tb);
			}
			vipalias_unlock();
		}
	}else if ((argc == 2 || argc == 3) && strcmp(argv[1],"list")==0){
		if (vipalias_lock() != -1){
			vipalias_read(tb);
			map<string,int> mp;
			for (vector<string>::iterator it=tb.begin();
				it != tb.end(); it++){
				if (strcmp(it->c_str(),"-")!=0){
					mp[*it] = it - tb.begin();
				}
			}
			map<int,string> v2dev;
			devlist_read (v2dev);
			if (argc == 3){
				// List the IP of one vserver
				bool found = false;
				for (map<string,int>::iterator it=mp.begin();
					it != mp.end(); it++){
					const char *key = it->first.c_str();
					key = strchr(key,'-');
					if (key != NULL && strcmp(argv[2],key+1)==0){
						int pos = it->second;
						const char *device = v2dev[pos].c_str();
						char tmp[100],ip[20],mask[20],bcast[20];
						snprintf (tmp,sizeof(tmp)-1,"%s:V%u",device,pos);
						ifconfig_getinfo (tmp,ip,mask,bcast);
						printf ("%s\t%s\n",ip,mask);
						found = true;
					}
				}
				if (!found){
					fprintf (stderr,"No IP defined for vserver %s\n",argv[2]);
				}
			}else{
				for (map<string,int>::iterator it=mp.begin();
					it != mp.end(); it++){
					int pos = it->second;
					const char *device = v2dev[pos].c_str();
					char tmp[100],ip[20],mask[20],bcast[20];
					snprintf (tmp,sizeof(tmp)-1,"%s:V%u",device,pos);
					ifconfig_getinfo (tmp,ip,mask,bcast);
					char ali[100],ipmask[100];
					snprintf (ali,sizeof(ali)-1,"%s:V%d",device,pos);
					snprintf (ipmask,sizeof(ipmask)-1,"%s/%s",ip,mask);
					printf ("%-10s %-30s %s\n",ali,ipmask,it->first.c_str());
				}
			}
			vipalias_unlock();
		}
	}else{
		usage();
	}
	return ret;
}