source: MondoRescue/branches/stable/mindi-busybox/networking/libiproute/libnetlink.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * 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 <sys/socket.h>
#include <sys/uio.h>

#include "libbb.h"
#include "libnetlink.h"

void rtnl_close(struct rtnl_handle *rth)
{
    close(rth->fd);
}

int xrtnl_open(struct rtnl_handle *rth/*, unsigned subscriptions*/)
{
    socklen_t addr_len;

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

    rth->fd = xsocket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

    memset(&rth->local, 0, sizeof(rth->local));
    rth->local.nl_family = AF_NETLINK;
    /*rth->local.nl_groups = subscriptions;*/

    xbind(rth->fd, (struct sockaddr*)&rth->local, sizeof(rth->local));
    addr_len = sizeof(rth->local);
    if (getsockname(rth->fd, (struct sockaddr*)&rth->local, &addr_len) < 0)
        bb_perror_msg_and_die("cannot getsockname");
    if (addr_len != sizeof(rth->local))
        bb_error_msg_and_die("wrong address length %d", addr_len);
    if (rth->local.nl_family != AF_NETLINK)
        bb_error_msg_and_die("wrong address family %d", rth->local.nl_family);
    rth->seq = time(NULL);
    return 0;
}

int xrtnl_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 xsendto(rth->fd, (void*)&req, sizeof(req),
                 (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 xsendto(rth->fd, buf, len, (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);
}

static 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;
            bb_perror_msg("OVERRUN");
            continue;
        }
        if (status == 0) {
            bb_error_msg("EOF on netlink");
            return -1;
        }
        if (msg.msg_namelen != sizeof(nladdr)) {
            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);
                    if (err < 0)
                        return err;
                } */
                goto skip_it;
            }

            if (h->nlmsg_type == NLMSG_DONE) {
                return 0;
            }
            if (h->nlmsg_type == NLMSG_ERROR) {
                struct nlmsgerr *l_err = (struct nlmsgerr*)NLMSG_DATA(h);
                if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
                    bb_error_msg("ERROR truncated");
                } else {
                    errno = -l_err->error;
                    bb_perror_msg("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) {
            bb_error_msg("message truncated");
            continue;
        }
        if (status) {
            bb_error_msg_and_die("remnant of size %d!", status);
        }
    }
}

int xrtnl_dump_filter(struct rtnl_handle *rth,
        int (*filter)(struct sockaddr_nl *, struct nlmsghdr *n, void *),
        void *arg1)
{
    int ret = rtnl_dump_filter(rth, filter, arg1/*, NULL, NULL*/);
    if (ret < 0)
        bb_error_msg_and_die("dump terminated");
    return ret;
}

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) {
        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) {
            if (errno == EINTR) {
                continue;
            }
            bb_perror_msg("OVERRUN");
            continue;
        }
        if (status == 0) {
            bb_error_msg("EOF on netlink");
            return -1;
        }
        if (msg.msg_namelen != sizeof(nladdr)) {
            bb_error_msg_and_die("sender address length == %d", msg.msg_namelen);
        }
        for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
            int l_err;
            int len = h->nlmsg_len;
            int l = len - sizeof(*h);

            if (l<0 || len>status) {
                if (msg.msg_flags & MSG_TRUNC) {
                    bb_error_msg("truncated message");
                    return -1;
                }
                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) {
                    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)) {
                    bb_error_msg("ERROR truncated");
                } else {
                    errno = -err->error;
                    if (errno == 0) {
                        if (answer) {
                            memcpy(answer, h, h->nlmsg_len);
                        }
                        return 0;
                    }
                    bb_perror_msg("RTNETLINK answers");
                }
                return -1;
            }
            if (answer) {
                memcpy(answer, h, h->nlmsg_len);
                return 0;
            }

            bb_error_msg("unexpected reply!");

            status -= NLMSG_ALIGN(len);
            h = (struct nlmsghdr*)((char*)h + NLMSG_ALIGN(len));
        }
        if (msg.msg_flags & MSG_TRUNC) {
            bb_error_msg("message truncated");
            continue;
        }
        if (status) {
            bb_error_msg_and_die("remnant of size %d!", status);
        }
    }
}

int addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t 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, uint32_t 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) {
        bb_error_msg("deficit %d, rta_len=%d!", len, rta->rta_len);
    }
    return 0;
}