/*
* 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;
}