#include <u.h>#include <sys/ioctl.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <asm/types.h>#include <net/if_arp.h>#include <linux/netlink.h>#include <linux/rtnetlink.h>#include <net/if.h>#include <libc.h>#include <ip.h> /* * Use netlink sockets to find interfaces. * Thanks to Erik Quanstrom. */static intnetlinkrequest(int fd, int type, int (*fn)(struct nlmsghdr *h, Ipifc**, int), 	Ipifc **ifc, int index){	char buf[1024];	int n;	struct sockaddr_nl nl;	struct {		struct nlmsghdr nlh;		struct rtgenmsg g;	} req;	struct nlmsghdr *h; 	memset(&nl, 0, sizeof nl);	nl.nl_family = AF_NETLINK; 	memset(&req, 0, sizeof req);	req.nlh.nlmsg_len = sizeof req;	req.nlh.nlmsg_type = type;	req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;	req.nlh.nlmsg_pid = 0;	req.nlh.nlmsg_seq = 1;	req.g.rtgen_family = AF_NETLINK; 	if(sendto(fd, (void*)&req, sizeof req, 0, (struct sockaddr*)&nl, sizeof nl) < 0)		return -1; 	while((n=read(fd, buf, sizeof buf)) > 0){		for(h=(struct nlmsghdr*)buf; NLMSG_OK(h, n); h = NLMSG_NEXT(h, n)){			if(h->nlmsg_type == NLMSG_DONE)				return 0;			if(h->nlmsg_type == NLMSG_ERROR){				werrstr("netlink error");				return -1;			}			if(fn(h, ifc, index) < 0)				return -1;		}	}	werrstr("netlink error");	return -1;} static intdevsocket(void){	/* we couldn't care less which one; just want to talk to the kernel! */	static int dumb[3] = { AF_INET, AF_PACKET, AF_INET6 };	int i, fd;		for(i=0; i<nelem(dumb); i++)		if((fd = socket(dumb[i], SOCK_DGRAM, 0)) >= 0)			return fd;	return -1;} static intparsertattr(struct rtattr **dst, int ndst, struct nlmsghdr *h, int type, int skip){	struct rtattr *src;	int len;		len = h->nlmsg_len - NLMSG_LENGTH(skip);	if(len < 0 || h->nlmsg_type != type){		werrstr("attrs too short");		return -1;	}	src = (struct rtattr*)((char*)NLMSG_DATA(h) + NLMSG_ALIGN(skip)); 	memset(dst, 0, ndst*sizeof dst[0]);	for(; RTA_OK(src, len); src = RTA_NEXT(src, len))		if(src->rta_type < ndst)			dst[src->rta_type] = src;	return 0;} static voidrta2ip(int af, uchar *ip, struct rtattr *rta){	memset(ip, 0, IPaddrlen);		switch(af){	case AF_INET:		memmove(ip, v4prefix, IPv4off);		memmove(ip+IPv4off, RTA_DATA(rta), IPv4addrlen);		break;	case AF_INET6:		memmove(ip, RTA_DATA(rta), IPaddrlen);		break;	}} static intgetlink(struct nlmsghdr *h, Ipifc **ipifclist, int index){	char *p;	int fd;	struct rtattr *attr[IFLA_MAX+1];	struct ifinfomsg *ifi;	Ipifc *ifc;		ifi = (struct ifinfomsg*)NLMSG_DATA(h);	if(index >= 0 && ifi->ifi_index != index)		return 0; 	ifc = mallocz(sizeof *ifc, 1);	if(ifc == nil)		return -1;	ifc->index = ifi->ifi_index; 	while(*ipifclist)		ipifclist = &(*ipifclist)->next;	*ipifclist = ifc; 	if(parsertattr(attr, nelem(attr), h, RTM_NEWLINK, sizeof(struct ifinfomsg)) < 0)		return -1; 	if(attr[IFLA_IFNAME])		p = (char*)RTA_DATA(attr[IFLA_IFNAME]);	else		p = "nil";	strecpy(ifc->dev, ifc->dev+sizeof ifc->dev, p); 	if(attr[IFLA_MTU])		ifc->mtu = *(int*)RTA_DATA(attr[IFLA_MTU]); 	/*	 * Does not work on old Linux systems,	 * and not really necessary for my purposes.	 * Uncomment if you want it bad.	 *	if(attr[IFLA_STATS]){		struct rtnl_link_stats *s; 		s = RTA_DATA(attr[IFLA_STATS]);		ifc->pktin = s->rx_packets;		ifc->pktout = s->tx_packets;		ifc->errin = s->rx_errors;		ifc->errout = s->tx_errors;	}	 *	 */ 	if((fd = devsocket()) > 0){		struct ifreq ifr; 		memset(&ifr, 0, sizeof ifr);		strncpy(ifr.ifr_name, p, IFNAMSIZ);		ifr.ifr_mtu = 0;		if(ioctl(fd, SIOCGIFMTU, &ifr) >= 0)			ifc->rp.linkmtu = ifr.ifr_mtu; 		memset(&ifr, 0, sizeof ifr);		strncpy(ifr.ifr_name, p, IFNAMSIZ);		if(ioctl(fd, SIOCGIFHWADDR, &ifr) >= 0		&& ifr.ifr_hwaddr.sa_family == ARPHRD_ETHER)			memmove(ifc->ether, ifr.ifr_hwaddr.sa_data, 6);				close(fd);	}	return 0;} static intgetaddr(struct nlmsghdr *h, Ipifc **ipifclist, int index){	int mask;	Ipifc *ifc;	Iplifc *lifc, **l;	struct ifaddrmsg *ifa;	struct rtattr *attr[IFA_MAX+1];		USED(index); 	ifa = (struct ifaddrmsg*)NLMSG_DATA(h);	for(ifc=*ipifclist; ifc; ifc=ifc->next)		if(ifc->index == ifa->ifa_index)			break;	if(ifc == nil)		return 0;	if(parsertattr(attr, nelem(attr), h, RTM_NEWADDR, sizeof(struct ifaddrmsg)) < 0)		return -1;		lifc = mallocz(sizeof *lifc, 1);	if(lifc == nil)		return -1;	for(l=&ifc->lifc; *l; l=&(*l)->next)		;	*l = lifc; 	if(attr[IFA_ADDRESS] == nil)		attr[IFA_ADDRESS] = attr[IFA_LOCAL];	if(attr[IFA_ADDRESS] == nil)		return 0; 	rta2ip(ifa->ifa_family, lifc->ip, attr[IFA_ADDRESS]);		mask = ifa->ifa_prefixlen/8;	if(ifa->ifa_family == AF_INET)		mask += IPv4off;	memset(lifc->mask, 0xFF, mask);	memmove(lifc->net, lifc->ip, mask);		if(attr[IFA_CACHEINFO]){		struct ifa_cacheinfo *ci; 		ci = RTA_DATA(attr[IFA_CACHEINFO]);		lifc->preflt = ci->ifa_prefered;		lifc->validlt = ci->ifa_valid;	}	return 0;} Ipifc*readipifc(char *net, Ipifc *ifc, int index){	int fd; 	USED(net);	freeipifc(ifc);	ifc = nil;		fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);	if(fd < 0)		return nil;	ifc = nil;	if(netlinkrequest(fd, RTM_GETLINK, getlink, &ifc, index) < 0	|| netlinkrequest(fd, RTM_GETADDR, getaddr, &ifc, index) < 0){		close(fd);		freeipifc(ifc);		return nil;	}	close(fd);	return ifc;}