hostap/src/drivers/netlink.c

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/*
* Netlink helper functions for driver wrappers
* Copyright (c) 2002-2009, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "eloop.h"
#include "priv_netlink.h"
#include "netlink.h"
struct netlink_data {
struct netlink_config *cfg;
int sock;
};
static void netlink_receive_link(struct netlink_data *netlink,
void (*cb)(void *ctx, struct ifinfomsg *ifi,
u8 *buf, size_t len),
struct nlmsghdr *h)
{
if (cb == NULL || NLMSG_PAYLOAD(h, 0) < sizeof(struct ifinfomsg))
return;
cb(netlink->cfg->ctx, NLMSG_DATA(h),
(u8 *) NLMSG_DATA(h) + NLMSG_ALIGN(sizeof(struct ifinfomsg)),
NLMSG_PAYLOAD(h, sizeof(struct ifinfomsg)));
}
static void netlink_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
struct netlink_data *netlink = eloop_ctx;
char buf[8192];
int left;
struct sockaddr_nl from;
socklen_t fromlen;
struct nlmsghdr *h;
int max_events = 10;
try_again:
fromlen = sizeof(from);
left = recvfrom(sock, buf, sizeof(buf), MSG_DONTWAIT,
(struct sockaddr *) &from, &fromlen);
if (left < 0) {
if (errno != EINTR && errno != EAGAIN)
wpa_printf(MSG_INFO, "netlink: recvfrom failed: %s",
strerror(errno));
return;
}
h = (struct nlmsghdr *) buf;
while (NLMSG_OK(h, left)) {
switch (h->nlmsg_type) {
case RTM_NEWLINK:
netlink_receive_link(netlink, netlink->cfg->newlink_cb,
h);
break;
case RTM_DELLINK:
netlink_receive_link(netlink, netlink->cfg->dellink_cb,
h);
break;
}
h = NLMSG_NEXT(h, left);
}
if (left > 0) {
wpa_printf(MSG_DEBUG, "netlink: %d extra bytes in the end of "
"netlink message", left);
}
if (--max_events > 0) {
/*
* Try to receive all events in one eloop call in order to
* limit race condition on cases where AssocInfo event, Assoc
* event, and EAPOL frames are received more or less at the
* same time. We want to process the event messages first
* before starting EAPOL processing.
*/
goto try_again;
}
}
struct netlink_data * netlink_init(struct netlink_config *cfg)
{
struct netlink_data *netlink;
struct sockaddr_nl local;
netlink = os_zalloc(sizeof(*netlink));
if (netlink == NULL)
return NULL;
netlink->sock = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (netlink->sock < 0) {
wpa_printf(MSG_ERROR, "netlink: Failed to open netlink "
"socket: %s", strerror(errno));
netlink_deinit(netlink);
return NULL;
}
os_memset(&local, 0, sizeof(local));
local.nl_family = AF_NETLINK;
local.nl_groups = RTMGRP_LINK;
if (bind(netlink->sock, (struct sockaddr *) &local, sizeof(local)) < 0)
{
wpa_printf(MSG_ERROR, "netlink: Failed to bind netlink "
"socket: %s", strerror(errno));
netlink_deinit(netlink);
return NULL;
}
eloop_register_read_sock(netlink->sock, netlink_receive, netlink,
NULL);
netlink->cfg = cfg;
return netlink;
}
void netlink_deinit(struct netlink_data *netlink)
{
if (netlink == NULL)
return;
if (netlink->sock >= 0) {
eloop_unregister_read_sock(netlink->sock);
close(netlink->sock);
}
os_free(netlink->cfg);
os_free(netlink);
}
int netlink_send_oper_ifla(struct netlink_data *netlink, int ifindex,
int linkmode, int operstate)
{
struct {
struct nlmsghdr hdr;
struct ifinfomsg ifinfo;
char opts[16];
} req;
struct rtattr *rta;
static int nl_seq;
ssize_t ret;
os_memset(&req, 0, sizeof(req));
req.hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.hdr.nlmsg_type = RTM_SETLINK;
req.hdr.nlmsg_flags = NLM_F_REQUEST;
req.hdr.nlmsg_seq = ++nl_seq;
req.hdr.nlmsg_pid = 0;
req.ifinfo.ifi_family = AF_UNSPEC;
req.ifinfo.ifi_type = 0;
req.ifinfo.ifi_index = ifindex;
req.ifinfo.ifi_flags = 0;
req.ifinfo.ifi_change = 0;
if (linkmode != -1) {
rta = aliasing_hide_typecast(
((char *) &req + NLMSG_ALIGN(req.hdr.nlmsg_len)),
struct rtattr);
rta->rta_type = IFLA_LINKMODE;
rta->rta_len = RTA_LENGTH(sizeof(char));
*((char *) RTA_DATA(rta)) = linkmode;
req.hdr.nlmsg_len = NLMSG_ALIGN(req.hdr.nlmsg_len) +
RTA_LENGTH(sizeof(char));
}
if (operstate != -1) {
rta = aliasing_hide_typecast(
((char *) &req + NLMSG_ALIGN(req.hdr.nlmsg_len)),
struct rtattr);
rta->rta_type = IFLA_OPERSTATE;
rta->rta_len = RTA_LENGTH(sizeof(char));
*((char *) RTA_DATA(rta)) = operstate;
req.hdr.nlmsg_len = NLMSG_ALIGN(req.hdr.nlmsg_len) +
RTA_LENGTH(sizeof(char));
}
wpa_printf(MSG_DEBUG, "netlink: Operstate: linkmode=%d, operstate=%d",
linkmode, operstate);
ret = send(netlink->sock, &req, req.hdr.nlmsg_len, 0);
if (ret < 0) {
wpa_printf(MSG_DEBUG, "netlink: Sending operstate IFLA "
"failed: %s (assume operstate is not supported)",
strerror(errno));
}
return ret < 0 ? -1 : 0;
}