/*

 * 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>

 *

 * Modified by Ted Felix (www.tedfelix.com) to fix warnings.

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.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 "libc_compat.h"

#include "libnetlink.h"

void rtnl_close(struct rtnl_handle *rth)

{

	if (rth->fd >= 0) {

		close(rth->fd);

		rth->fd = -1;

	}

}

int rtnl_open_byproto(struct rtnl_handle *rth, unsigned subscriptions,

		      int protocol)

{

	socklen_t addr_len;

	int sndbuf = 32768;

	int rcvbuf = 32768;

	memset(rth, 0, sizeof(struct rtnl_handle));

	rth->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);

	if (rth->fd < 0) {

		perror("Cannot open netlink socket");

		return -1;

	}

	if (setsockopt(rth->fd,SOL_SOCKET,SO_SNDBUF,&sndbuf,sizeof(sndbuf)) < 0) {

		perror("SO_SNDBUF");

		return -1;

	}

	if (setsockopt(rth->fd,SOL_SOCKET,SO_RCVBUF,&rcvbuf,sizeof(rcvbuf)) < 0) {

		perror("SO_RCVBUF");

		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_open(struct rtnl_handle *rth, unsigned subscriptions)

{

	return rtnl_open_byproto(rth, subscriptions, NETLINK_ROUTE);

}

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;

	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 = 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, const 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] = {

		{ .iov_base = &nlh, .iov_len = sizeof(nlh) },

		{ .iov_base = req, .iov_len = len }

	};

	struct msghdr msg = {

		.msg_name = &nladdr,

		.msg_namelen = 	sizeof(nladdr),

		.msg_iov = iov,

		.msg_iovlen = 2,

	};

	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,

		     rtnl_filter_t filter,

		     void *arg1,

		     rtnl_filter_t junk,

		     void *arg2)

{

	struct sockaddr_nl nladdr;

	struct iovec iov;

	struct msghdr msg = {

		.msg_name = &nladdr,

		.msg_namelen = sizeof(nladdr),

		.msg_iov = &iov,

		.msg_iovlen = 1,

	};

	char buf[16384];

	iov.iov_base = buf;

	while (1) {

		int status;

		struct nlmsghdr *h;

		iov.iov_len = sizeof(buf);

		status = TEMP_FAILURE_RETRY ( recvmsg(rth->fd, &msg, MSG_CMSG_CLOEXEC) );

		if (status < 0) {

			perror("OVERRUN");

			continue;

		}

		if (status == 0) {

			fprintf(stderr, "EOF on netlink\n");

			return -1;

		}

		h = (struct nlmsghdr*)buf;

		while (NLMSG_OK(h, (unsigned)status)) {

			int err;

			if (nladdr.nl_pid != 0 ||

			    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 *msgerr = (struct nlmsgerr*)NLMSG_DATA(h);

				if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {

					fprintf(stderr, "ERROR truncated\n");

				} else {

					errno = -msgerr->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,

	      rtnl_filter_t junk,

	      void *jarg)

{

	int status;

	unsigned seq;

	struct nlmsghdr *h;

	struct sockaddr_nl nladdr;

	struct iovec iov = {

		.iov_base = (void*) n,

		.iov_len = n->nlmsg_len

	};

	struct msghdr msg = {

		.msg_name = &nladdr,

		.msg_namelen = sizeof(nladdr),

		.msg_iov = &iov,

		.msg_iovlen = 1,

	};

	char   buf[16384];

	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;

	}

	memset(buf,0,sizeof(buf));

	iov.iov_base = buf;

	while (1) {

		iov.iov_len = sizeof(buf);

		status = TEMP_FAILURE_RETRY ( recvmsg(rtnl->fd, &msg, MSG_CMSG_CLOEXEC) );

		if (status < 0) {

			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; (unsigned)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 (nladdr.nl_pid != (unsigned)peer ||

			    h->nlmsg_pid != rtnl->local.nl_pid ||

			    h->nlmsg_seq != seq) {

				if (junk) {

					err = junk(&nladdr, h, jarg);

					if (err < 0)

						return err;

				}

				/* Don't forget to skip that message. */

				status -= NLMSG_ALIGN(len);

				h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));

				continue;

			}

			if (h->nlmsg_type == NLMSG_ERROR) {

				struct nlmsgerr *msgerr = (struct nlmsgerr*)NLMSG_DATA(h);

				if ((unsigned)l < sizeof(struct nlmsgerr)) {

					fprintf(stderr, "ERROR truncated\n");

				} else {

					errno = -msgerr->error;

					if (errno == 0) {

						if (answer)

							memcpy(answer, h, h->nlmsg_len);

						return 0;

					}

					perror("RTNETLINK1 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,

		rtnl_filter_t handler,

		void *jarg)

{

	int status;

	struct nlmsghdr *h;

	struct sockaddr_nl nladdr;

	struct iovec iov;

	struct msghdr msg = {

		.msg_name = &nladdr,

		.msg_namelen = sizeof(nladdr),

		.msg_iov = &iov,

		.msg_iovlen = 1,

	};

	char   buf[8192];

	memset(&nladdr, 0, sizeof(nladdr));

	nladdr.nl_family = AF_NETLINK;

	nladdr.nl_pid = 0;

	nladdr.nl_groups = 0;

	iov.iov_base = buf;

	while (1) {

		iov.iov_len = sizeof(buf);

		status = TEMP_FAILURE_RETRY ( recvmsg(rtnl->fd, &msg, MSG_CMSG_CLOEXEC) );

		if (status < 0) {

			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; (unsigned)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, rtnl_filter_t handler,

		   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;

		int l;

		status = TEMP_FAILURE_RETRY ( fread(&buf, 1, sizeof(*h), rtnl) );

		if (status < 0) {

			perror("rtnl_from_file: fread");

			return -1;

		}

		if (status == 0)

			return 0;

		len = h->nlmsg_len;

		l = len - sizeof(*h);

		if (l<0 || (unsigned)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 ((int)NLMSG_ALIGN(n->nlmsg_len) + len > maxlen) {

		fprintf(stderr,"addattr32: Error! max allowed bound %d exceeded\n",maxlen);

		return -1;

	}

	rta = NLMSG_TAIL(n);

	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, const void *data,

	      int alen)

{

	int len = RTA_LENGTH(alen);

	struct rtattr *rta;

	if ((int)NLMSG_ALIGN(n->nlmsg_len) + (int)RTA_ALIGN(len) > maxlen) {

		fprintf(stderr, "addattr_l ERROR: message exceeded bound of %d\n",maxlen);

		return -1;

	}

	rta = NLMSG_TAIL(n);

	rta->rta_type = type;

	rta->rta_len = len;

	memcpy(RTA_DATA(rta), data, alen);

	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);

	return 0;

}

int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)

{

	if ((int)NLMSG_ALIGN(n->nlmsg_len) + (int)NLMSG_ALIGN(len) > maxlen) {

		fprintf(stderr, "addraw_l ERROR: message exceeded bound of %d\n",maxlen);

		return -1;

	}

	memcpy(NLMSG_TAIL(n), data, len);

	memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);

	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);

	return 0;

}

int rta_addattr32(struct rtattr *rta, int maxlen, int type, __u32 data)

{

	int len = RTA_LENGTH(4);

	struct rtattr *subrta;

	if ((int)RTA_ALIGN(rta->rta_len) + len > maxlen) {

		fprintf(stderr,"rta_addattr32: Error! max allowed bound %d exceeded\n",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,

		  const void *data, int alen)

{

	struct rtattr *subrta;

	int len = RTA_LENGTH(alen);

	if ((int)RTA_ALIGN(rta->rta_len) + (int)RTA_ALIGN(len) > maxlen) {

		fprintf(stderr,"rta_addattr_l: Error! max allowed bound %d exceeded\n",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) + RTA_ALIGN(len);

	return 0;

}

int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)

{

	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));

	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;

}

int parse_rtattr_byindex(struct rtattr *tb[], int max, struct rtattr *rta, int len)

{

	int i = 0;

	memset(tb, 0, sizeof(struct rtattr *) * max);

	while (RTA_OK(rta, len)) {

		if (rta->rta_type <= max && i < max)

			tb[i++] = rta;

		rta = RTA_NEXT(rta,len);

	}

	if (len)

		fprintf(stderr, "!!!Deficit %d, rta_len=%d\n", len, rta->rta_len);

	return i;

}