/* * libnetlink.c	RTnetlink service routines. * *		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. * * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * */#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <syslog.h>#include <fcntl.h>#include <net/if_arp.h>#include <sys/socket.h>#include <netinet/in.h>#include <string.h>#include <errno.h>#include <time.h>#include <sys/uio.h>#include "libnetlink.h"int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions){	int addr_len;	memset(rth, 0, sizeof(rth));	rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);	if (rth->fd < 0) {		perror("Cannot open netlink socket");		return -1;	}	memset(&rth->local, 0, sizeof(rth->local));	rth->local.nl_family = AF_NETLINK;	rth->local.nl_groups = subscriptions;	if (bind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local)) < 0) {		perror("Cannot bind netlink socket");		return -1;	}	addr_len = sizeof(rth->local);	if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {		perror("Cannot getsockname");		return -1;	}	if (addr_len != sizeof(rth->local)) {		fprintf(stderr, "Wrong address length %d\n", addr_len);		return -1;	}	if (rth->local.nl_family != AF_NETLINK) {		fprintf(stderr, "Wrong address family %d\n", rth->local.nl_family);		return -1;	}	rth->seq = time(NULL);	return 0;}int rtnl_wilddump_request(struct rtnl_handle *rth, int family, int type){	struct {		struct nlmsghdr nlh;		struct rtgenmsg g;	} req;	struct sockaddr_nl nladdr;	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	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 = rth->dump = ++rth->seq;	req.g.rtgen_family = family;	return sendto(rth->fd, (void*)&req, sizeof(req), 0, (struct sockaddr*)&nladdr, sizeof(nladdr));}int rtnl_send(struct rtnl_handle *rth, char *buf, int len){	struct sockaddr_nl nladdr;	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	return sendto(rth->fd, buf, len, 0, (struct sockaddr*)&nladdr, sizeof(nladdr));}int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len){	struct nlmsghdr nlh;	struct sockaddr_nl nladdr;	struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } };	struct msghdr msg = {		(void*)&nladdr, sizeof(nladdr),		iov,	2,		NULL,	0,		0	};	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	nlh.nlmsg_len = NLMSG_LENGTH(len);	nlh.nlmsg_type = type;	nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;	nlh.nlmsg_pid = 0;	nlh.nlmsg_seq = rth->dump = ++rth->seq;	return sendmsg(rth->fd, &msg, 0);}int rtnl_dump_filter(struct rtnl_handle *rth,		     int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),		     void *arg1,		     int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),		     void *arg2){	char	buf[8192];	struct sockaddr_nl nladdr;	struct iovec iov = { buf, sizeof(buf) };	while (1) {		int status;		struct nlmsghdr *h;		struct msghdr msg = {			(void*)&nladdr, sizeof(nladdr),			&iov,	1,			NULL,	0,			0		};		status = recvmsg(rth->fd, &msg, 0);		if (status < 0) {			if (errno == EINTR)				continue;			perror("OVERRUN");			continue;		}		if (status == 0) {			fprintf(stderr, "EOF on netlink\n");			return -1;		}		if (msg.msg_namelen != sizeof(nladdr)) {			fprintf(stderr, "sender address length == %d\n", msg.msg_namelen);			exit(1);		}		h = (struct nlmsghdr*)buf;		while (NLMSG_OK(h, status)) {			int err;			if (h->nlmsg_pid != rth->local.nl_pid ||			    h->nlmsg_seq != rth->dump) {				if (junk) {					err = junk(&nladdr, h, arg2);					if (err < 0)						return err;				}				goto skip_it;			}			if (h->nlmsg_type == NLMSG_DONE)				return 0;			if (h->nlmsg_type == NLMSG_ERROR) {				struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);				if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {					fprintf(stderr, "ERROR truncated\n");				} else {					errno = -err->error;					perror("RTNETLINK answers");				}				return -1;			}			err = filter(&nladdr, h, arg1);			if (err < 0)				return err;skip_it:			h = NLMSG_NEXT(h, status);		}		if (msg.msg_flags & MSG_TRUNC) {			fprintf(stderr, "Message truncated\n");			continue;		}		if (status) {			fprintf(stderr, "!!!Remnant of size %d\n", status);			exit(1);		}	}}int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,	      unsigned groups, struct nlmsghdr *answer,	      int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),	      void *jarg){	int status;	unsigned seq;	struct nlmsghdr *h;	struct sockaddr_nl nladdr;	struct iovec iov = { (void*)n, n->nlmsg_len };	char   buf[8192];	struct msghdr msg = {		(void*)&nladdr, sizeof(nladdr),		&iov,	1,		NULL,	0,		0	};	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	nladdr.nl_pid = peer;	nladdr.nl_groups = groups;	n->nlmsg_seq = seq = ++rtnl->seq;	if (answer == NULL)		n->nlmsg_flags |= NLM_F_ACK;	status = sendmsg(rtnl->fd, &msg, 0);	if (status < 0) {		perror("Cannot talk to rtnetlink");		return -1;	}	iov.iov_base = buf;	iov.iov_len = sizeof(buf);	while (1) {		status = recvmsg(rtnl->fd, &msg, 0);		if (status < 0) {			if (errno == EINTR)				continue;			perror("OVERRUN");			continue;		}		if (status == 0) {			fprintf(stderr, "EOF on netlink\n");			return -1;		}		if (msg.msg_namelen != sizeof(nladdr)) {			fprintf(stderr, "sender address length == %d\n", msg.msg_namelen);			exit(1);		}		for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {			int err;			int len = h->nlmsg_len;			int l = len - sizeof(*h);			if (l<0 || len>status) {				if (msg.msg_flags & MSG_TRUNC) {					fprintf(stderr, "Truncated message\n");					return -1;				}				fprintf(stderr, "!!!malformed message: len=%d\n", len);				exit(1);			}			if (h->nlmsg_pid != rtnl->local.nl_pid ||			    h->nlmsg_seq != seq) {				if (junk) {					err = junk(&nladdr, h, jarg);					if (err < 0)						return err;				}				continue;			}			if (h->nlmsg_type == NLMSG_ERROR) {				struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);				if (l < sizeof(struct nlmsgerr)) {					fprintf(stderr, "ERROR truncated\n");				} else {					errno = -err->error;					if (errno == 0) {						if (answer)							memcpy(answer, h, h->nlmsg_len);						return 0;					}					perror("RTNETLINK answers");				}				return -1;			}			if (answer) {				memcpy(answer, h, h->nlmsg_len);				return 0;			}			fprintf(stderr, "Unexpected reply!!!\n");			status -= NLMSG_ALIGN(len);			h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));		}		if (msg.msg_flags & MSG_TRUNC) {			fprintf(stderr, "Message truncated\n");			continue;		}		if (status) {			fprintf(stderr, "!!!Remnant of size %d\n", status);			exit(1);		}	}}int rtnl_listen(struct rtnl_handle *rtnl, 	      int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),	      void *jarg){	int status;	struct nlmsghdr *h;	struct sockaddr_nl nladdr;	struct iovec iov;	char   buf[8192];	struct msghdr msg = {		(void*)&nladdr, sizeof(nladdr),		&iov,	1,		NULL,	0,		0	};	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	nladdr.nl_pid = 0;	nladdr.nl_groups = 0;	iov.iov_base = buf;	iov.iov_len = sizeof(buf);	while (1) {		status = recvmsg(rtnl->fd, &msg, 0);		if (status < 0) {			if (errno == EINTR)				continue;			perror("OVERRUN");			continue;		}		if (status == 0) {			fprintf(stderr, "EOF on netlink\n");			return -1;		}		if (msg.msg_namelen != sizeof(nladdr)) {			fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen);			exit(1);		}		for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {			int err;			int len = h->nlmsg_len;			int l = len - sizeof(*h);			if (l<0 || len>status) {				if (msg.msg_flags & MSG_TRUNC) {					fprintf(stderr, "Truncated message\n");					return -1;				}				fprintf(stderr, "!!!malformed message: len=%d\n", len);				exit(1);			}			err = handler(&nladdr, h, jarg);			if (err < 0)				return err;			status -= NLMSG_ALIGN(len);			h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));		}		if (msg.msg_flags & MSG_TRUNC) {			fprintf(stderr, "Message truncated\n");			continue;		}		if (status) {			fprintf(stderr, "!!!Remnant of size %d\n", status);			exit(1);		}	}}int rtnl_from_file(FILE *rtnl, 	      int (*handler)(struct sockaddr_nl *,struct nlmsghdr *n, void *),	      void *jarg){	int status;	struct sockaddr_nl nladdr;	char   buf[8192];	struct nlmsghdr *h = (void*)buf;	memset(&nladdr, 0, sizeof(nladdr));	nladdr.nl_family = AF_NETLINK;	nladdr.nl_pid = 0;	nladdr.nl_groups = 0;	while (1) {		int err, len, type;		int l;		status = fread(&buf, 1, sizeof(*h), rtnl);		if (status < 0) {			if (errno == EINTR)				continue;			perror("rtnl_from_file: fread");			return -1;		}		if (status == 0)			return 0;		len = h->nlmsg_len;		type= h->nlmsg_type;		l = len - sizeof(*h);		if (l<0 || len>sizeof(buf)) {			fprintf(stderr, "!!!malformed message: len=%d @%lu\n",				len, ftell(rtnl));			return -1;		}		status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl);		if (status < 0) {			perror("rtnl_from_file: fread");			return -1;		}		if (status < l) {			fprintf(stderr, "rtnl-from_file: truncated message\n");			return -1;		}		err = handler(&nladdr, h, jarg);		if (err < 0)			return err;	}}int addattr32(struct nlmsghdr *n, int maxlen, int type, __u32 data){	int len = RTA_LENGTH(4);	struct rtattr *rta;	if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)		return -1;	rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));	rta->rta_type = type;	rta->rta_len = len;	memcpy(RTA_DATA(rta), &data, 4);	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;	return 0;}int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen){	int len = RTA_LENGTH(alen);	struct rtattr *rta;	if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)		return -1;	rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));	rta->rta_type = type;	rta->rta_len = len;	memcpy(RTA_DATA(rta), data, alen);	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;	return 0;}int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data){	int len = RTA_LENGTH(4);	struct rtattr *subrta;	if (RTA_ALIGN(rta->rta_len) + len > maxlen)		return -1;	subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));	subrta->rta_type = type;	subrta->rta_len = len;	memcpy(RTA_DATA(subrta), &data, 4);	rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;	return 0;}int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen){	struct rtattr *subrta;	int len = RTA_LENGTH(alen);	if (RTA_ALIGN(rta->rta_len) + len > maxlen)		return -1;	subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));	subrta->rta_type = type;	subrta->rta_len = len;	memcpy(RTA_DATA(subrta), data, alen);	rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;	return 0;}int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len){	while (RTA_OK(rta, len)) {		if (rta->rta_type <= max)			tb[rta->rta_type] = rta;		rta = RTA_NEXT(rta,len);	}	if (len)		fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);	return 0;}