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387 lines
8.9 KiB
C
387 lines
8.9 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* libnetlink.c RTnetlink service routines.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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*/
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#include <sys/socket.h>
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#include <sys/uio.h>
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#include "libbb.h"
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#include "libnetlink.h"
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void rtnl_close(struct rtnl_handle *rth)
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{
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close(rth->fd);
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}
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int xrtnl_open(struct rtnl_handle *rth/*, unsigned subscriptions*/)
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{
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socklen_t addr_len;
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memset(rth, 0, sizeof(rth));
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rth->fd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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memset(&rth->local, 0, sizeof(rth->local));
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rth->local.nl_family = AF_NETLINK;
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/*rth->local.nl_groups = subscriptions;*/
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xbind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local));
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addr_len = sizeof(rth->local);
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if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0)
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bb_perror_msg_and_die("cannot getsockname");
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if (addr_len != sizeof(rth->local))
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bb_error_msg_and_die("wrong address length %d", addr_len);
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if (rth->local.nl_family != AF_NETLINK)
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bb_error_msg_and_die("wrong address family %d", rth->local.nl_family);
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rth->seq = time(NULL);
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return 0;
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}
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int xrtnl_wilddump_request(struct rtnl_handle *rth, int family, int type)
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{
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struct {
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struct nlmsghdr nlh;
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struct rtgenmsg g;
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} req;
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struct sockaddr_nl nladdr;
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memset(&nladdr, 0, sizeof(nladdr));
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nladdr.nl_family = AF_NETLINK;
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req.nlh.nlmsg_len = sizeof(req);
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req.nlh.nlmsg_type = type;
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req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
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req.nlh.nlmsg_pid = 0;
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req.nlh.nlmsg_seq = rth->dump = ++rth->seq;
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req.g.rtgen_family = family;
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return xsendto(rth->fd, (void*)&req, sizeof(req),
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(struct sockaddr*)&nladdr, sizeof(nladdr));
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}
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int rtnl_send(struct rtnl_handle *rth, char *buf, int len)
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{
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struct sockaddr_nl nladdr;
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memset(&nladdr, 0, sizeof(nladdr));
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nladdr.nl_family = AF_NETLINK;
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return xsendto(rth->fd, buf, len, (struct sockaddr*)&nladdr, sizeof(nladdr));
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}
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int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req, int len)
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{
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struct nlmsghdr nlh;
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struct sockaddr_nl nladdr;
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struct iovec iov[2] = { { &nlh, sizeof(nlh) }, { req, len } };
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struct msghdr msg = {
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(void*)&nladdr, sizeof(nladdr),
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iov, 2,
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NULL, 0,
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0
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};
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memset(&nladdr, 0, sizeof(nladdr));
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nladdr.nl_family = AF_NETLINK;
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nlh.nlmsg_len = NLMSG_LENGTH(len);
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nlh.nlmsg_type = type;
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nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
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nlh.nlmsg_pid = 0;
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nlh.nlmsg_seq = rth->dump = ++rth->seq;
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return sendmsg(rth->fd, &msg, 0);
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}
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static int rtnl_dump_filter(struct rtnl_handle *rth,
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int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
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void *arg1/*,
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int (*junk)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
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void *arg2*/)
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{
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char buf[8192];
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struct sockaddr_nl nladdr;
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struct iovec iov = { buf, sizeof(buf) };
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while (1) {
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int status;
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struct nlmsghdr *h;
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struct msghdr msg = {
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(void*)&nladdr, sizeof(nladdr),
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&iov, 1,
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NULL, 0,
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0
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};
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status = recvmsg(rth->fd, &msg, 0);
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if (status < 0) {
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if (errno == EINTR)
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continue;
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bb_perror_msg("OVERRUN");
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continue;
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}
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if (status == 0) {
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bb_error_msg("EOF on netlink");
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return -1;
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}
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if (msg.msg_namelen != sizeof(nladdr)) {
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bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
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}
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h = (struct nlmsghdr*)buf;
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while (NLMSG_OK(h, status)) {
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int err;
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if (nladdr.nl_pid != 0 ||
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h->nlmsg_pid != rth->local.nl_pid ||
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h->nlmsg_seq != rth->dump) {
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/* if (junk) {
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err = junk(&nladdr, h, arg2);
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if (err < 0)
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return err;
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} */
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goto skip_it;
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}
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if (h->nlmsg_type == NLMSG_DONE) {
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return 0;
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}
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if (h->nlmsg_type == NLMSG_ERROR) {
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struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
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if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
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bb_error_msg("ERROR truncated");
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} else {
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errno = -l_err->error;
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bb_perror_msg("RTNETLINK answers");
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}
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return -1;
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}
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err = filter(&nladdr, h, arg1);
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if (err < 0)
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return err;
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skip_it:
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h = NLMSG_NEXT(h, status);
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}
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if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("message truncated");
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continue;
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}
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if (status) {
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bb_error_msg_and_die("remnant of size %d!", status);
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}
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}
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}
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int xrtnl_dump_filter(struct rtnl_handle *rth,
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int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
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void *arg1)
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{
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int ret = rtnl_dump_filter(rth, filter, arg1/*, NULL, NULL*/);
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if (ret < 0)
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bb_error_msg_and_die("dump terminated");
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return ret;
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}
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int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
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unsigned groups, struct nlmsghdr *answer,
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int (*junk)(struct sockaddr_nl *,struct nlmsghdr *n, void *),
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void *jarg)
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{
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int status;
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unsigned seq;
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struct nlmsghdr *h;
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struct sockaddr_nl nladdr;
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struct iovec iov = { (void*)n, n->nlmsg_len };
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char buf[8192];
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struct msghdr msg = {
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(void*)&nladdr, sizeof(nladdr),
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&iov, 1,
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NULL, 0,
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0
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};
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memset(&nladdr, 0, sizeof(nladdr));
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nladdr.nl_family = AF_NETLINK;
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nladdr.nl_pid = peer;
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nladdr.nl_groups = groups;
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n->nlmsg_seq = seq = ++rtnl->seq;
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if (answer == NULL) {
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n->nlmsg_flags |= NLM_F_ACK;
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}
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status = sendmsg(rtnl->fd, &msg, 0);
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if (status < 0) {
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bb_perror_msg("cannot talk to rtnetlink");
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return -1;
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}
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iov.iov_base = buf;
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while (1) {
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iov.iov_len = sizeof(buf);
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status = recvmsg(rtnl->fd, &msg, 0);
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if (status < 0) {
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if (errno == EINTR) {
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continue;
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}
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bb_perror_msg("OVERRUN");
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continue;
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}
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if (status == 0) {
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bb_error_msg("EOF on netlink");
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return -1;
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}
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if (msg.msg_namelen != sizeof(nladdr)) {
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bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
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}
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for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
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int l_err;
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int len = h->nlmsg_len;
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int l = len - sizeof(*h);
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if (l<0 || len>status) {
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if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("truncated message");
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return -1;
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}
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bb_error_msg_and_die("malformed message: len=%d!", len);
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}
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if (nladdr.nl_pid != peer ||
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h->nlmsg_pid != rtnl->local.nl_pid ||
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h->nlmsg_seq != seq) {
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if (junk) {
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l_err = junk(&nladdr, h, jarg);
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if (l_err < 0) {
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return l_err;
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}
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}
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continue;
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}
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if (h->nlmsg_type == NLMSG_ERROR) {
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struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
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if (l < sizeof(struct nlmsgerr)) {
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bb_error_msg("ERROR truncated");
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} else {
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errno = -err->error;
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if (errno == 0) {
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if (answer) {
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memcpy(answer, h, h->nlmsg_len);
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}
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return 0;
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}
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bb_perror_msg("RTNETLINK answers");
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}
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return -1;
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}
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if (answer) {
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memcpy(answer, h, h->nlmsg_len);
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return 0;
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}
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bb_error_msg("unexpected reply!");
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status -= NLMSG_ALIGN(len);
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h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
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}
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if (msg.msg_flags & MSG_TRUNC) {
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bb_error_msg("message truncated");
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continue;
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}
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if (status) {
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bb_error_msg_and_die("remnant of size %d!", status);
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}
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}
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}
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int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data)
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{
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int len = RTA_LENGTH(4);
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struct rtattr *rta;
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if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
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return -1;
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rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
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rta->rta_type = type;
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rta->rta_len = len;
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memcpy(RTA_DATA(rta), &data, 4);
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n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
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return 0;
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}
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int addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, int alen)
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{
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int len = RTA_LENGTH(alen);
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struct rtattr *rta;
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if (NLMSG_ALIGN(n->nlmsg_len) + len > maxlen)
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return -1;
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rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
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rta->rta_type = type;
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rta->rta_len = len;
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memcpy(RTA_DATA(rta), data, alen);
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n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
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return 0;
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}
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int rta_addattr32(struct rtattr *rta, int maxlen, int type, uint32_t data)
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{
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int len = RTA_LENGTH(4);
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struct rtattr *subrta;
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if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
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return -1;
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}
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subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
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subrta->rta_type = type;
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subrta->rta_len = len;
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memcpy(RTA_DATA(subrta), &data, 4);
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rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
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return 0;
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}
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int rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data, int alen)
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{
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struct rtattr *subrta;
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int len = RTA_LENGTH(alen);
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if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
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return -1;
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}
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subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
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subrta->rta_type = type;
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subrta->rta_len = len;
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memcpy(RTA_DATA(subrta), data, alen);
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rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
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return 0;
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}
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int parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
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{
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while (RTA_OK(rta, len)) {
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if (rta->rta_type <= max) {
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tb[rta->rta_type] = rta;
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}
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rta = RTA_NEXT(rta,len);
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}
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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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}
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return 0;
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}
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