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6dd778e837
Receiving a message in libmnl is a somewhat involved operation. Devlink's mnlg library has an implementation that is going to be handy for other tools as well. Extract it into a new helper. Signed-off-by: Petr Machata <me@pmachata.org> Signed-off-by: David Ahern <dsahern@gmail.com>
111 lines
2.3 KiB
C
111 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* mnl_utils.c Helpers for working with libmnl.
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*/
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#include <errno.h>
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#include <string.h>
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#include <time.h>
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#include <libmnl/libmnl.h>
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#include "libnetlink.h"
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#include "mnl_utils.h"
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#include "utils.h"
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struct mnl_socket *mnlu_socket_open(int bus)
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{
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struct mnl_socket *nl;
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int one = 1;
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nl = mnl_socket_open(bus);
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if (nl == NULL)
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return NULL;
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mnl_socket_setsockopt(nl, NETLINK_CAP_ACK, &one, sizeof(one));
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mnl_socket_setsockopt(nl, NETLINK_EXT_ACK, &one, sizeof(one));
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if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0)
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goto err_bind;
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return nl;
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err_bind:
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mnl_socket_close(nl);
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return NULL;
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}
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struct nlmsghdr *mnlu_msg_prepare(void *buf, uint32_t nlmsg_type, uint16_t flags,
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void *extra_header, size_t extra_header_size)
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{
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struct nlmsghdr *nlh;
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void *eh;
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nlh = mnl_nlmsg_put_header(buf);
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nlh->nlmsg_type = nlmsg_type;
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nlh->nlmsg_flags = flags;
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nlh->nlmsg_seq = time(NULL);
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eh = mnl_nlmsg_put_extra_header(nlh, extra_header_size);
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memcpy(eh, extra_header, extra_header_size);
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return nlh;
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}
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static int mnlu_cb_noop(const struct nlmsghdr *nlh, void *data)
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{
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return MNL_CB_OK;
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}
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static int mnlu_cb_error(const struct nlmsghdr *nlh, void *data)
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{
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const struct nlmsgerr *err = mnl_nlmsg_get_payload(nlh);
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/* Netlink subsystems returns the errno value with different signess */
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if (err->error < 0)
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errno = -err->error;
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else
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errno = err->error;
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if (nl_dump_ext_ack(nlh, NULL))
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return MNL_CB_ERROR;
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return err->error == 0 ? MNL_CB_STOP : MNL_CB_ERROR;
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}
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static int mnlu_cb_stop(const struct nlmsghdr *nlh, void *data)
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{
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int len = *(int *)NLMSG_DATA(nlh);
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if (len < 0) {
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errno = -len;
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nl_dump_ext_ack_done(nlh, len);
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return MNL_CB_ERROR;
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}
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return MNL_CB_STOP;
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}
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static mnl_cb_t mnlu_cb_array[NLMSG_MIN_TYPE] = {
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[NLMSG_NOOP] = mnlu_cb_noop,
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[NLMSG_ERROR] = mnlu_cb_error,
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[NLMSG_DONE] = mnlu_cb_stop,
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[NLMSG_OVERRUN] = mnlu_cb_noop,
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};
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int mnlu_socket_recv_run(struct mnl_socket *nl, unsigned int seq, void *buf, size_t buf_size,
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mnl_cb_t cb, void *data)
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{
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unsigned int portid = mnl_socket_get_portid(nl);
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int err;
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do {
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err = mnl_socket_recvfrom(nl, buf, buf_size);
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if (err <= 0)
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break;
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err = mnl_cb_run2(buf, err, seq, portid,
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cb, data, mnlu_cb_array,
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ARRAY_SIZE(mnlu_cb_array));
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} while (err > 0);
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return err;
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}
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