busybox/networking/libiproute/libnetlink.c

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/*
* 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 "libbb.h"
#include <sys/socket.h>
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#include <errno.h>
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#include <string.h>
#include <time.h>
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#include <unistd.h>
#include <sys/uio.h>
#include "libnetlink.h"
void rtnl_close(struct rtnl_handle *rth)
{
close(rth->fd);
}
int rtnl_open(struct rtnl_handle *rth, unsigned subscriptions)
{
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socklen_t addr_len;
memset(rth, 0, sizeof(rth));
rth->fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (rth->fd < 0) {
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bb_perror_msg("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) {
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bb_perror_msg("Cannot bind netlink socket");
return -1;
}
addr_len = sizeof(rth->local);
if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0) {
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bb_perror_msg("Cannot getsockname");
return -1;
}
if (addr_len != sizeof(rth->local)) {
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bb_error_msg("Wrong address length %d", addr_len);
return -1;
}
if (rth->local.nl_family != AF_NETLINK) {
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bb_error_msg("Wrong address family %d", 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;
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bb_perror_msg("OVERRUN");
continue;
}
if (status == 0) {
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bb_error_msg("EOF on netlink");
return -1;
}
if (msg.msg_namelen != sizeof(nladdr)) {
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bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
}
h = (struct nlmsghdr*)buf;
while (NLMSG_OK(h, 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);
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if (err < 0) {
return err;
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}
}
goto skip_it;
}
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if (h->nlmsg_type == NLMSG_DONE) {
return 0;
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}
if (h->nlmsg_type == NLMSG_ERROR) {
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struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
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bb_error_msg("ERROR truncated");
} else {
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errno = -l_err->error;
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bb_perror_msg("RTNETLINK answers");
}
return -1;
}
err = filter(&nladdr, h, arg1);
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if (err < 0) {
return err;
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}
skip_it:
h = NLMSG_NEXT(h, status);
}
if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("Message truncated");
continue;
}
if (status) {
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bb_error_msg_and_die("!!!Remnant of size %d", status);
}
}
}
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;
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if (answer == NULL) {
n->nlmsg_flags |= NLM_F_ACK;
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}
status = sendmsg(rtnl->fd, &msg, 0);
if (status < 0) {
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bb_perror_msg("Cannot talk to rtnetlink");
return -1;
}
iov.iov_base = buf;
while (1) {
iov.iov_len = sizeof(buf);
status = recvmsg(rtnl->fd, &msg, 0);
if (status < 0) {
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if (errno == EINTR) {
continue;
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}
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bb_perror_msg("OVERRUN");
continue;
}
if (status == 0) {
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bb_error_msg("EOF on netlink");
return -1;
}
if (msg.msg_namelen != sizeof(nladdr)) {
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bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
}
for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
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int l_err;
int len = h->nlmsg_len;
int l = len - sizeof(*h);
if (l<0 || len>status) {
if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("Truncated message");
return -1;
}
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bb_error_msg_and_die("!!!malformed message: len=%d", len);
}
if (nladdr.nl_pid != peer ||
h->nlmsg_pid != rtnl->local.nl_pid ||
h->nlmsg_seq != seq) {
if (junk) {
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l_err = junk(&nladdr, h, jarg);
if (l_err < 0) {
return l_err;
}
}
continue;
}
if (h->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
if (l < sizeof(struct nlmsgerr)) {
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bb_error_msg("ERROR truncated");
} else {
errno = -err->error;
if (errno == 0) {
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if (answer) {
memcpy(answer, h, h->nlmsg_len);
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}
return 0;
}
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bb_perror_msg("RTNETLINK answers");
}
return -1;
}
if (answer) {
memcpy(answer, h, h->nlmsg_len);
return 0;
}
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bb_error_msg("Unexpected reply!!!");
status -= NLMSG_ALIGN(len);
h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
}
if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("Message truncated");
continue;
}
if (status) {
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bb_error_msg_and_die("!!!Remnant of size %d", status);
}
}
}
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;
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if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
return -1;
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}
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);
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if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
return -1;
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}
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)) {
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if (rta->rta_type <= max) {
tb[rta->rta_type] = rta;
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}
rta = RTA_NEXT(rta,len);
}
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if (len) {
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bb_error_msg("!!!Deficit %d, rta_len=%d", len, rta->rta_len);
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}
return 0;
}